Mechanics of the Household
by E. S. Keene · English · Gutenberg #50846 · 793,688 chars · public domain (US)
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Title: Mechanics of the Household
Author: E. S. Keene
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MECHANICS OF THE HOUSEHOLD
* * * * * *
_McGraw-Hill Book Co., Inc._
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MECHANICS OF THE HOUSEHOLD
A Course of Study Devoted to Domestic Machinery and
Household Mechanical Appliances
E. S. KEENE
Dean of Mechanic Arts
North Dakota Agricultural College
FIRST EDITION
Mcgraw-Hill Book Company, Inc.
239 West 39th Street. New York
London: Hill Publishing Co., Ltd.
6 & 8 Bouverie St., E. C.
1918
Copyright, 1918, by the
Mcgraw-Hill Book Company, Inc.
INTRODUCTION
This book is intended to be a presentation of the physical principles
and mechanism employed in the equipment that has been developed for
domestic convenience. Its aim is to provide information relative to
the general practice of domestic engineering. The scope of the work is
such as to present: first, the use of household mechanical appliances;
second, the principles involved and the mechanism employed. It is not
exhaustive, neither does it touch many of the secondary topics that
might be discussed in connection with the various subjects. It does,
however, describe at least one representative piece of each type of
household apparatus that is used in good practice.
The mechanism used in the equipment of a modern dwelling is worthy of
greater attention, as a course of study, than it has been heretofore
accorded. The fact that any house, rural or urban, may be provided with
all domestic conveniences included in: furnace heating, mechanical
temperature regulation, lighting facilities, water supply, sewage
disposal and other appliances, indicates the general use of domestic
machinery in great variety. To comprehend the application and
adaptability of this mechanism requires a knowledge of its general plan
of construction and principles of operation.
Heating systems in great variety utilize steam, hot water, or hot air
as the vehicle of transfer of heat from the furnace, throughout the
house. Each of these is made in the form of special heating plants that
may be adapted, in some special advantage to the various conditions of
use. A knowledge of their working principles and general mechanical
arrangement furnishes a fund of information that is of every day
application.
The systems available for household water distribution take advantage
of natural laws, which aided by suitable mechanical devices and
conveniently arranged systems of pipes, provide water-supply plants to
satisfy any condition of service. They may be of simple form, to suit
a cottage, or elaborated to the requirements of large residences and
made entirely automatic in action. In each, the apparatus consists
of parts that perform definite functions. The parts may be obtained
from different makers and assembled as a working unit or the plant
may be purchased complete as some special system of water supply. An
acquaintance with domestic water supply apparatus may be of service in
every condition of life.
The type of illumination for a house or a group of buildings, may be
selected from a variety of lighting systems. In rural homes, choice may
be made between oil gas, gasolene, acetylene and electricity, each of
which is used in a number of successful plants that differ only in the
mechanism employed.
Any building arranged with toilet, kitchen and laundry conveniences
must be provided with some form of sewage disposal. Private disposal
plants are made to meet many conditions of service. The mechanical
construction and principles of operation are not difficult to
comprehend and their adaptation to a given service is only an
intelligent conception of the possible conditions of disposal,
dependent on the natural surroundings.
There are few communities where household equipment cannot be found to
illustrate each of the subjects discussed. Most modern school houses
are equipped for automatic control of temperature, ventilation and
humidity. They are further provided with systems of gas, water and
electric distribution and arrangements for sewage disposal. These
facilities furnish demonstration apparatus that are also examples of
their application. Additional examples of the various forms of plumbing
and pipe fittings, valves, traps and water fixtures may be found in the
shop of dealers in plumbers and steam-fitters supplies.
Attention is called to the value of observing houses in process of
construction and the means employed for the placement of the pipes for
the sewer, gas, water, electric conduits, etc. These are generally
located by direction of the specifications provided by the architect
but observation of their installation is necessary for a comprehension
of actual working conditions. It is suggested that the work be made
that of, first, acquiring an idea of established practice, and second,
that of investigating the examples of its application.
CONTENTS
PREFACE v
CHAPTER I
PAGE
THE STEAM HEATING PLANT 1
Heat of Vaporization--Steam Temperature--Gage Pressure--Absolute
Pressure--Two-pipe System--Separate-return System--Overhead
or Drop System--Water-filled Radiators--Air Vents--Automatic
Air Vents--Steam Radiator Valves--The House-heating Steam
Boiler--Boiler Trimmings--The Water Column--The Steam Gage--The
Safety Valve--The Draft Regulator--Rule for Proportioning
Radiators--Proportioning the Size of Mains--Forms of
Radiators--Radiator Finishings--Pipe Coverings--Vapor-system
Heating.
CHAPTER II
THE HOT-WATER HEATING PLANT 37
The Low-pressure Hot-water System--The High-pressure Hot-water
System--Heating-plant Design--Overhead System of Hot-water
Heating--Expansion Tanks--Radiator Connection--Hot-water
Radiators--Hot-water Radiator Valves--Air Vents--Automatic
Hot-water Air Vents.
CHAPTER III
THE HOT-AIR FURNACE 51
Construction--Furnace-gas Leaks--Location of the
Furnace--Flues--Combination Hot-air and Hot-water Heater.
CHAPTER IV
TEMPERATURE REGULATION 59
Hand Regulation--Damper Regulator for Steam Boiler--Damper
Regulators for Hot-water Furnaces--The Thermostat Motor--Combined
Thermostat and Damper Regulator--Thermostat-motor Connections.
CHAPTER V
MANAGEMENT OF HEATING PLANTS 70
General Advice--The Economy of Good Draft--General Firing
Rules--Weather and Time of Day--Night Firing--First-day
Firing--Other Day Firing--Economy and Fuels--For Burning Soft
Coal--For Burning Coke--Other Rules for Water Boilers--Air-vent
Valves on Radiators--The Air Valves--End of the Season--The Right
Chimney Flue--“Smokey” Chimneys.
CHAPTER VI
PLUMBING 82
Water Supply--Water Cocks--Bibb-cocks--Self-closing
Bibbs--Lever-handle Bibbs--Fuller Cocks--Wash-tray Bibbs--Basin
Cocks--Pantry Cocks--Sill Cocks--Valves--Kitchen and
Laundry Fixtures--The Bathroom--Bath Tubs--Wash Stands and
Lavatories--Traps--Back-venting--Soil Pipe--Water Closets--Washout
Closets--Washdown Closets--Siphon-jet Closet--Flush Tanks--Low-down
Flush Tank--Opening Stopped Pipes--Sewer Gas--Range Boilers--The
Water-back--Excessive Pressure--Blow-off Cock--Location of Range
Boiler--Double Heater Connections--Horizontal Range Boilers--Tank
Heaters--Overheater Water--Furnace Hot-water Heaters--Instantaneous
Heaters.
CHAPTER VII
WATER SUPPLY 125
Water Analysis--Pokegama Water--River Water--Artesian
Water--Medical Water--Organic Matter--Ammonia--Hardness
in Water--Iron in Water--Water Softening With Hydrated
Silicates--Chlorine--Polluted Water--Pollution of Wells--Safe
Distance in the Location of Wells--Surface Pollution of
Wells--Water Table--The Divining Rod--Selection of a Type of
Well--Flowing Wells--Construction of Wells--Dug Wells--Open
Wells--The Ideal Well--Coverings of Concrete--Artesian
Wells--Driven Wells--Bored Wells--Cleaning Wells--Gases in
Wells--Peculiarities of Wells--Breathing Well--Freezing
Wells--Pumps--The Lift Pump--The Force Pump--Tank Pump--Well
Pumps--Wooden Pump--Pumps for Driven Wells--Deep-well
Pumps--Tubular Well Cylinders--Chain Pumps--Rain Water
Cisterns--Filters--The Hydraulic Ram--Single-acting Hydraulic
Ram--The Double-acting Hydraulic Ram--Domestic Water-supply
Plants--Gravity Water Supply--Pressure-tank System of Water
Supply--The Pressure Tank--Power Water-supply Plants--Electric
Power Water Supply--The Water Lift.
CHAPTER VIII
SEWAGE DISPOSAL 168
The Septic Tank--The Septic Tank With a Sand-bed Filter--The Septic
Tank and Anaerobic Filter--Limit of Efficiency.
CHAPTER IX
COAL 182
Oxidation of Hydrocarbons--Graphitic Anthracite--Cannel
Coal--Lignite--Peat--Wood--Charcoal--Coke--Gas-coke--Briquettes
--Comparative Value of Coal to Other Fuels--Price of Coal.
CHAPTER X
ATMOSPHERIC HUMIDITY 196
Humidity of the Air--Relative Humidity--The Hygrometer--The
Hygrodeik--Dial Hygrometers--The Swiss Cottage
“Barometer”--Dew-point--To Determine the Dew-point--Frost
Prediction--Prevention of Frost--Humidifying Apparatus.
CHAPTER XI
VENTILATION 219
Quantity of Air Discharged by a Flue--Cost of Ventilation--The
Wolpert Air Tester--Pneumatic Temperature Regulation--Mechanical
Ventilation--The Plenum Method--Ventilation Apparatus--Air
Conditioning--Humidifying Plants--Vaporization as a Cooling
Agent--Air-cooling Plants--Humidity Control.
CHAPTER XII
GASEOUS AND LIQUID FUELS 250
Gaseous and Liquid Fuels--Coal Gas--All-oil Water Gas--Pintsch
Gas--Blau Gas--Water Gas--Measurement of Gas--Gas Meters How
to Read the Index--Prepayment Meters--Gas-service Rules--Gas
Ranges--Lighting and Heating with Gasoline--Gasoline--Kerosene--The
Cold-process Gas Machine--The Hollow-wire System of Gasoline
Lighting and Heating--Mantle Gas Lamps--Open-flame Gas Burners--The
Inverted-mantle Gasoline Lamp--Portable Gasoline Lamp--Central
Generator Plants--Central-generator Gas Lamps--Boulevard
Lamps--Gasoline Sad Irons--Alcohol Sad Irons--Alcohol Table
Stoves--Danger from Gaseous and Liquid Fuels--Acetylene-gas
Machine--Types of Acetylene Generators--Gas Lighters--Acetylene
Stoves.
CHAPTER XIII
ELECTRICITY 305
Incandescent Electric Lamps--The Mazda Lamp--Candlepower--Lamp
Labels--Illumination--The Foot-candle--The
Lumen--Reflectors--Choice of Reflector--Lamp Transformers--Units
of Electrical Measurements--Miniature Lamps--Effects of Voltage
Variations--Turn-down Electric Lamps--The Dim-a-lite--Gas-filled
Lamps--Daylight Lamps--Miniature Tungsten Lamps--Flash Lights--The
Electric Flat-iron--The Electric Toaster--Motors, Fuse
Plugs--Electric Heaters--Intercommunicating Telephones--Electric
Signals--Buzzers--Burglar Alarms--Annunciators--Table
Pushes--Bell-ringing Transformers--The Recording Wattmeter--To
Read the Meter--State Regulation of Meter Service--Electric
Batteries--Battery Formation--Battery Testers--Electric
Conductors--Lamp Cord--Portable Cord--Annunciator Wire--Private
Electric Generating Plants--Storage Batteries--The Pilot
Cell--National Electrical Code--Electric Light Wiring--Outlet
Boxes--Automatic Door Switch--Plug Receptacles--Heater Switch,
Pilot and Receptacle--Service Switch--Local Switches--Pilot
Lights--Wall and Ceiling Sockets--Drop Lights.
INDEX 385
MECHANICS OF THE HOUSEHOLD
CHAPTER I
THE STEAM HEATING PLANT
The use of steam as a means of heating dwellings is common in every
part of the civilized world. Plants of all sizes are constructed, that
not only give satisfactory service but are efficient in the use of
fuel, and require the minimum amount of attention.
The manufacture of steam heating apparatus has come to be a distinct
industry, and represents a special branch of engineering. Many
manufacturing companies, pursue this line of business exclusively.
The result has been the development of many distinctive features and
systems of steam heating, that are very excellent for the purposes
intended.
Practice has shown that large plants can be operated more economically
than small ones. Steam may be carried through underground, insulated
pipes to great distances with but small loss of heat. This has lead to
the sale of exhaust steam, from the engines of manufacturing plants,
for heating purposes and the establishment of community heating plants,
where the dwellings of a neighborhood are heated from a central heating
plant; each subscriber paying for his heat according to the number of
square feet of radiating surface his house contains.
In the practice most commonly followed, with small steam heating
plants, the steam is generated in a boiler located at any convenient
place, but commonly in the basement. The steam is distributed through
insulated pipes to the rooms, where it gives up its heat to cast-iron
radiators, and from them it is imparted to the air; partly by radiation
but most of the heat is transmitted to the air in direct contact with
the radiator surface.
The heating capacity of a radiator is determined by its outside surface
area, and is commonly termed, _radiating surface_ or _heating surface_.
Radiators of different styles and sizes are listed by manufacturers,
according to the amount of heating surface each possesses. Radiators
are sold at a definite amount per square foot, and may be made to
contain any amount of heating surface, for different heights from 12 to
45 inches.
The widespread use of steam as a means of heating buildings is due to
its remarkable heat content. When water is converted into vapor the
change is attended by the absorption of a large amount of heat. No
matter at what temperature water is evaporated, a definite quantity of
heat is required to merely change the water into vapor without changing
its temperature. The heat used to vaporize water in a steam boiler is
given up in the radiators when the steam is condensed. It is because of
this property that steam is such a convenient vehicle for transferring
heat from the furnace--where it is generated--to the place to be
warmed. This heat of vaporization is really the property which gives to
steam its usefulness as a means of heating.
=Heat of Vaporization.=--The temperature of the steam is comparatively
an unimportant factor in the amount of heat given up by the radiator.
It is the heat liberated at the time the steam changes from vapor to
water that produces the greatest effect in changing the temperature of
the house. This evolution of heat by condensation is sometimes called
the latent heat of vaporization. It is the heat that was used up in
changing the water to vapor. The following table of the properties of
steam shows the temperatures and exact amounts of latent heat that
correspond to various pressures.
When water at the boiling point is turned into steam at the same
temperature, there are required 965.7 B.t.u. for each pound of water
changed into steam. In the table, this is the latent heat of the
vapor of water at 0, gage pressure. As the pressure and corresponding
temperature rise, the latent heat becomes less. At 10 pounds gage
pressure, the temperature of the steam is practically 240°F., but the
heat of vaporization is 946 thermal units. When the steam is changed
back into water, as it is when condensed in the radiators, this latent
heat becomes sensible and is that which heats the rooms. The steam
enters the radiators and, coming into contact with the relatively
colder walls, is condensed. As condensation takes place, the latent
heat of the steam becomes sensible heat and is absorbed by the
radiators and then transferred to the air of the rooms.
PROPERTIES OF STEAM
---------+----------+-------------+---------
Absolute | Gage | Temperature | Latent
pressure | pressure | | heat
---------+----------+-------------+---------
0 | 14.7 | 212.00 | 965.70
1 | 15.0 | 213.04 | 964.96
2 | 16.0 | 216.33 | 962.63
3 | 17.0 | 219.45 | 960.49
4 | 18.0 | 220.40 | 958.32
5 | 19.0 | 225.25 | 958.30
6 | 20.0 | 227.95 | 954.38
7 | 21.0 | 230.60 | 952.50
8 | 22.0 | 233.10 | 950.62
9 | 23.0 | 235.49 | 949.03
10 | 24.0 | 237.81 | 947.37
11 | 25.0 | 240.07 | 945.76
12 | 26.0 | 242.24 | 944.25
13 | 27.0 | 244.32 | 942.74
14 | 28.0 | 246.35 | 941.29
15 | 29.0 | 248.33 | 939.88
16 | 30.0 | 250.26 | 938.50
17 | 31.0 | 252.13 | 937.17
18 | 32.0 | 253.98 | 935.45
19 | 33.0 | 255.77 | 934.57
20 | 34.0 | 257.52 | 933.32
21 | 35.0 | 259.22 | 932.10
22 | 36.0 | 260.88 | 930.92
23 | 37.0 | 262.50 | 929.76
24 | 38.0 | 264.09 | 928.62
25 | 39.0 | 265.65 | 927.51
---------+----------+-------------+---------
Whenever water is evaporated, heat is used up at a rate that in amount
depends on its temperature and the quantity of water vaporized.
This heat of vaporization is important, not only in problems which
relate to steam heating but in all others where vapor of water exerts
an influence--ventilation of buildings, atmospheric humidity, the
formation of frost, refrigeration, and many other applications in
practice; this factor is one of the important items in quantitative
determinations of heat. It will appear repeatedly in considering
ventilation and humidity.
At temperatures below the boiling point of water, the heat of
vaporization gradually increases until, at the freezing point,
it is 1092 B.t.u. Water vaporizes at all temperatures--even ice
evaporates--and the cooling effect produced by evaporation from
sprinkled streets in summer, or the chilling sensation brought about
by the winds of winter are caused largely because of its effect.
The evaporation of perspiration from the body is one of the means
of keeping it cool. At the temperature of the body 98.6 the heat of
vaporization is 1046 B.t.u.
=Steam Temperatures.=--While the temperature of steam is an unimportant
factor in the heating of buildings there are many uses in which it
is of the greatest consequence. When steam is employed for cooking
or baking it is not the quantity of heat but its intensity that is
necessary for the accomplishment of its purpose.
Steam cookers must work at a temperature suitable to the articles
under preparation, and the length of time required in the process.
Examination of the table on page 3, will show that steam at the
pressure of the air or 0, gage pressure, has a temperature of 212°F.,
which for boiling is sufficiently intense for ordinary cooking; but
for all conditions required of steam cooking, a pressure of 25 pounds
gage pressure is required. The temperature corresponding to 25 pounds
is shown in the table as 267°F. Baking temperatures for oven baking as
for bread requires temperatures of 400°F. or higher. To bake by steam
at that temperature would require a gage pressure of 185 pounds to the
square inch.
=The British thermal unit= is the English unit of measure of heat. It
is the amount of heat required to raise the temperature of a pound of
water 1°F. From the table it will be seen that steam at 10 pounds gage
pressure, is only 27.4° hotter than it was at 0 pounds. In raising the
pressure of a pound of steam from 0 to 10 pounds, the steam gained
only 27.4 B.t.u. of heat. The amount of heat gained by raising the
pressure to 10 pounds is small as compared with the heat it received on
vaporizing. The extra fuel used up in raising the pressure is not well
expended. It is customary, therefore, in heating plants, to use only
enough pressure in the boiler to carry the steam through the system.
This amount is rarely more than 10 pounds and oftener but 3 or 4 pounds
pressure.
=Gage Pressure--Absolute Pressure.=--In the practice of engineering
among English speaking people, pressures are stated in pounds per
square inch, above the atmosphere. This is termed gage pressure. It
is that indicated by the gages of boilers, tanks, etc., subjected
to internal pressure. Under ordinary conditions the term pressure
is understood to mean gage pressure, the 0 point being that of the
pressure of the atmosphere. This system requires pressures below that
of the atmosphere to be expressed as a partial vacuum, a complete
vacuum being 14.7 pounds below the normal atmospheric pressure.
In order to measure positively all pressures above a vacuum, the normal
atmosphere is 14.7 pounds; all pressures above that point are continued
on the same scale, thus:
Gage pressure 0 = 14.7 absolute
Gage pressure 10 = 10 + 14.7 = 24.7 absolute
Gage pressure 20 = 20 + 14.7 = 34.7 absolute
Absolute pressures are, therefore, those of the gage plus the
additional amount due to the atmosphere. All references to pressure in
this work are intended to indicate gage pressure unless specifically
mentioned as absolute pressure.
Steam heating as applied to buildings may be considered under two
general methods: the pressure system in which steam under pressure
above the atmosphere is utilized to procure circulation; and the
vacuum system in which the steam is used at a pressure below that of
the atmosphere. Each of these systems is used under a great variety of
conditions, and to some is applied specific names but the principle of
operation is very much the same in all of a single class.
Steam heating plants are now seldom installed in the average home
but they are very much employed in apartment houses and the larger
residences. In large buildings and in groups of buildings heated
from a central point, steam is used for heating almost exclusively.
The type of plant employed for any given condition will depend on
the architecture of the buildings and their surroundings. In very
large buildings and in groups of buildings, the vacuum system is very
generally employed. This system has, as a special field of heating, the
elaborate plants required in large units.
The low-pressure gravity system of heating is used in buildings of
moderate size, large residences, schools, churches, apartment houses,
and the like. Under this form of steam heating is to be included vapor
heating systems. This is the same as the low-pressure plant except
that it operates under pressure only slightly above the atmosphere and
possesses features that frequently recommend its use over any other
form of steam heating. The term vapor heating is used to distinguish it
from the low-pressure system.
=The low-pressure gravity system=, with which we are most concerned,
takes its name from the conditions under which it works. The low
pressure refers to the pressure of the steam in the boiler, which is
generally 3 or 4 pounds; and since the water of condensation flows back
to the boiler by reason of gravity, it is a gravity system.
The placing of the pipes which are to carry the steam to the radiators
and return the water of condensation to the boiler may consist of
one or both of two standard arrangements. They are known as the
_single-pipe system_ and the _two-pipe system_.
[Illustration: FIG. 1.--Diagram of a gravity system steam heating
plant.]
Fig. 1 shows a diagram of a single-pipe system in its simplest form.
In the figure the pipe marked _supply and return_, connects the boiler
with the radiators. From the vertical pipe called a _riser_, the steam
is taken to the radiators through branch pipes that all slope toward
the riser, so that the water of condensation may readily flow back into
the boiler. The water of condensation, returning to the boiler, must
under this condition, flow in a direction contrary to the course of the
steam supplying the radiators. In Fig. 2 is given a simple application
of this system. A single pipe from the top of the boiler, in the
basement, marked _supply and return pipe_, connects with one radiator
on the floor above. The radiator and all of the connecting pipes are
set to drain the water of condensation into the boiler.
[Illustration: FIG. 2.--A simple form of steam heating plant. The
furnace fire is controlled by a thermostat and a damper regulator.]
When the valve is opened to admit steam to the radiator, the air vent
must also be opened to allow the escape of the contained air. The steam
will not diffuse with the air in the radiator and unless the air is
allowed to escape, the steam will not enter. As the steam enters the
cold radiator, it is rapidly condensed, and collects on the walls in
the form of dew, at the same time giving up its latent heat. The heat
is liberated as condensation takes place, and as the dew forms on the
radiator walls the heat is conducted directly to the iron. The water
runs to the bottom of the radiator and then through the pipes; back
to the boiler. The water occupies but relatively a little space and
may return through the same pipe, while more steam is entering the
radiator. As the steam condenses in the radiator, its reduction in
volume tends to reduce the pressure and thus aids additional steam from
the boiler to enter. In this manner a constant supply of heat enters
the radiator in the form of steam which when condensed goes back to the
boiler at a temperature very near the boiling point to be revaporized.
It should be kept in mind that it is the heat of vaporization, not the
temperature of the steam that is utilized in the radiator, and that the
heat of vaporization is the vehicle of transfer. The water returning to
the boiler may be at the boiling point and the steam supplying the heat
to the radiators may be at the same temperature.
[Illustration: FIG. 3.--A gravity system steam heating plant of two
radiators. The furnace is governed by a thermostat.]
Fig. 3 is a slightly different arrangement of the same boiler as that
shown in Fig. 2, connected with two radiators on different floors. The
same riser supplies both radiators with steam and takes the water of
condensation back to the boiler.
Fig. 4 is an example of the single-pipe system applied to a small
house. In the drawing, the boiler in the basement is shown connected
with four radiators on the first floor and three on the second
floor. The pipes connecting with the more distant radiators are only
extensions of the pipes connecting the radiators near the boiler. As
in Figs. 1, 2 and 3, all of the pipes and radiators are set to drain
back into the boiler. If at any place the pipe is so graded that a part
of the water is retained, poor circulation will result, because of the
restricted area of the pipe, and the radiators will not be properly
heated. This lack of drainage is also a common cause of hammering and
pounding in steam systems, known as _water-hammer_. The formation of
water-hammer is caused by steam flowing through a water-restricted
area, into a cold part of the system, where condensation takes place
very rapidly. The condensation of the steam is so rapid and complete
that the resulting vacuum draws the trapped water into the space with
the force of a hammer stroke. The hammering will continue so long as
the conditions exist. The pipes in the basement are suspended from the
floor joists by hangers as shown in the drawing. In practice the pipes
in the basement are covered with some form of insulating material to
prevent loss of heat.
[Illustration: FIG. 4.--The gravity system steam heating plant
installed in a dwelling.]
As stated above, the single-pipe system may be successfully used in all
house-heating plants except those of large size. It requires the least
amount of pipe and labor for installation of the circulating system and
when well constructed performs very satisfactorily all of the functions
required in a small heating plant.
One of the commonest causes of trouble in a single-pipe system is due
to the radiator connections. The single radiator connection requires
the entering steam and escaping water of condensation to pass through
the same opening. Under ordinary conditions this double office of the
radiator valve is accomplished with satisfaction but occasionally it
is the cause of considerable noise. At any time the valve is left only
partly open the steam will enter and condense because of the lower
pressure inside the radiator but the condensed water will not be able
to escape. The water has only the force of gravity to carry it out of
the radiators and if it meets no opposition will flow back through
the pipe to the boiler; but if it is required to pass a small opening
through which steam is flowing in a contrary direction, the water will
be retained in the radiators. Single-pipe radiators, therefore, work
satisfactorily only under conditions which will permit the steam to
enter and the water to leave as fast as it is formed. In ordinary use
the valve at any time is apt to be left slightly open and this produces
undesirable working conditions.
In larger buildings, where greater distances require longer runs
of pipe and more complicated connections, and where the volume of
condensed steam is too great to be taken care of in a single pipe, this
system does not work satisfactorily.
=Two-pipe System.=--Fig. 5 is a diagram of a two-pipe system. Here,
each radiator has a _supply pipe_, through which the steam enters, and
a _return pipe_ which conducts the water away. The branch pipes from
a common supply pipe or riser, carry steam to the various radiators
and all of the return pipes empty into a single return pipe that takes
the water back to its source. It will be noticed that in this case
the _riser_ also connects at the bottom with the return pipe. This
connection is made for the purpose of conducting away the condensation
that takes place in the connecting pipes. The water will always
stand in these pipes, at the same height as the water in the boiler.
The supply pipe from the boiler, and the branch pipes connecting
the radiators all slope toward the _riser_. The condensation in the
connecting pipes does not pass through the radiators as it returns to
the boiler.
An exception to this general rule is shown in the radiator on the
second floor. In this case the supply pipe slopes downward as it
approaches the radiator. To prevent carrying water through the
radiator, a small pipe under the left-hand valve connects with the
return pipe and the water is thus conducted to the main return pipe.
[Illustration: FIG. 5.--Diagram showing the arrangement of a two-pipe
steam plant.]
Fig. 6 is a simple application of the arrangement shown in Fig. 5.
The steam may be easily traced from the boiler to the radiators, and
back through the return pipes to its source. The pipe marked _R_ is
the connection between the main supply pipe and the return pipe that
takes away the condensation of the riser. It is connected to the main
return pipe below the water line of the boiler and, therefore, does
not interfere in any way with the passage of the steam. Each radiator
empties its water of condensation into a common return pipe, that
finally connects with the boiler below the water line.
[Illustration: FIG. 6.--A two-pipe steam heating plant.]
This arrangement may be elaborated to almost any extent and is an
improvement over the single-pipe system. It is quite commonly used as
a method of steam distribution, but it lacks the required elements
necessary to a positive circulation. As an example: Suppose that the
plant shown in Fig. 6 is working and that the radiator on the first
floor is hot, but the valves of the radiator on the second floor are
closed and it is cold. The steam entering at the valve _A_ of the lower
radiator is being condensed as fast as the heat is radiated. The steam
will pass on through the valve _B_ into the return pipe and as soon as
the return pipe becomes hot it will contain steam at practically the
same pressure as that in the supply pipe. This is what takes place in
every working steam plant. Now suppose that it is desired to heat the
radiator on the floor above. The steam valve _A_ of the upper radiator
is opened to admit steam and the return valve is also opened to allow
the water to escape. There is steam in both the supply and return pipes
of the radiator below at the same pressure, each tending to send steam
into the radiator above at opposite ends. This would make a condition
exactly the same as a single-pipe system, with a supply pipe at both
ends of the radiator and the result would, of course, be the same as in
the single-pipe system. There being no place for the water to escape
except against the incoming steam, the water will sometimes surge back
and forth with the customary noises peculiar to such conditions. It
must not be understood that this will always occur, because systems of
this kind are in use with fairly good results, but noisy radiators are
not at all rare when working under this condition and the cause is from
that described. To overcome this difficulty and change the system into
one in which there would be a positive circulation from _A_ to _B_, in
each radiator, allowing the steam always to enter at the valve _A_ and
escape at _B_, the system must be changed to that of _separate returns_.
[Illustration: FIG. 7.--Diagram of a separate return steam system.]
=Separate-return System.=--A diagram of a _separate-return_ system is
shown in Fig. 7. In this figure, the radiator, boiler and supply pipes
are the same as those of Fig. 5, but there is a separate return pipe
from each of the radiators, connecting with the main return pipe at a
point below the water line of the boiler. Examination of this diagram
will show that there is an independent circuit for the steam through
each radiator. The steam is taken from a common riser as before but
after passing through the radiator the water is returned by a separate
pipe to the main return pipe at the bottom of the boiler. Fig. 8 is an
application of _separate-return_ system. It is exactly the same as Fig.
6, except that each radiator has an independent return pipe. Steam must
always enter the radiators at the valves _A_ and leave at the valves
_B_. This makes a positive circulation that renders each radiator
independent of the others. There is no opportunity for steam to pass
through one radiator and interfere with the return water of another;
it, therefore, prevents the possibility of hammering or surging so
common in poorly designed steam systems.
Of all the methods of steam heating where the water of condensation
is returned to the boiler by reason of gravity this is the most
satisfactory. This plant requires a larger amount of pipe than the
other systems described and as a consequence the cost of installation
is greater but it repays in excellence of service the extra expense
incurred.
[Illustration: FIG. 8.--A separate return heating plant.]
=Overhead or Drop System.=--There is yet another gravity system of
steam heating that is sometimes used in large buildings where economy
in the use of pipe is desired; this is the _overhead_ or _drop_ system
shown in Fig. 9. It is not a common method of piping and is given here
only because of its occasional use. In the arrangement of the _drop_
system, the supply pipe for the radiators rises from the boiler to the
highest point of the system and the branch pipes for the radiators are
taken off from the descending pipe. Its action is the same as that of
a single-pipe system but the advantage gained by the arrangement is
that the steam in the main supply pipes travels in the same direction
as the returning water of condensation; the cause of _surging_ in long
_risers_ is thus eliminated.
The two-pipe systems of steam heating are more certain in action than
the single-pipe methods because there is nothing to interfere with
the progress of the steam on its way to the radiators. In long branch
pipes of the _single-pipe_ system, the returning water is frequently
caught by the advancing steam and carried to the end of the pipe, when
_slugging_ and _surging_ is the result.
[Illustration: FIG. 9.--Diagram of the overhead or drop system steam
plant.]
=Water-filled Radiators.=--Radiators frequently fill with water and are
noisy because of the position of the valve. This may be true in any
gravity system but particularly so in radiators having a single pipe.
When the valve of a single-pipe radiator is opened a very small amount,
the entering steam is immediately condensed but the water cannot escape
because the incoming steam entirely fills the opening. Under this
condition, the radiator may entirely fill with water. If the valve is
then opened wide, the imprisoned water has an opportunity to escape
while the steam is entering, but the entering steam and escaping water
sets up a water-hammer that sometimes is terrific and lasts until the
water is discharged from the radiator. The same condition may exist
in a two-pipe system, if the steam valve is slightly opened while the
escape valve is closed, but in a well-designed system the radiator will
be immediately emptied when both valves are open.
=Air Vents.=--All radiators must be provided with air vents. The
vent is placed near the top of the last loop of the radiator, at the
end opposite from the entering steam, as indicated in Figs. 2, 3, 6,
etc. The object of the vent is to allow the air to escape from the
radiator as the steam enters. Steam will not diffuse with the air and,
therefore, cannot enter the radiator until the air is discharged.
The air vent may be a simple cock such as is shown in Fig. 10, that
must be opened by hand when the steam is turned on, to allow the air
to escape, and closed when the steam appears at the vent; or it may
be an automatic vent, that opens when the radiator cools and closes
automatically when the radiator is filled with steam. There are many
makes of air vents of both hand-regulating and automatic types; of
the former, Fig. 10 furnishes a common example. The part _A_, in the
figure, is threaded and screws tightly into a hole made to receive it
in the end loop of the radiator. The part _B_ is a screw-plug that
closes the passage _C_, leading to the inside of the radiator. When
the steam is turned on, the vent must be opened until the air is
discharged, after which it is closed by the hand-wheel _D_.
[Illustration: FIG. 10. FIG. 11. FIG. 12. FIG. 13.
FIG. 10.--A common form of air vent for radiators.
FIG. 11.--An inexpensive automatic radiator air vent.
FIG. 12.--Monash No. 16 automatic air vent.
FIG. 13.--The Allen float, radiator air vent.]
=Automatic Air Vents.=--These vents depend for their action on the
expansion of a part of the valve due to the temperature of the steam.
The valve remains closed when hot and opens when cold. The difference
in temperature between the steam and the expelled air from the radiator
is the controlling factor. In the automatic vent shown in Fig. 11, the
part _A_ is screwed into the radiator loop. The discharge _C_ is open
to the air or connected with a drip pipe, which returns the water to
the basement. The cylinder _D_, which closes the passage _B_, is made
of a material of a high coefficient of expansion. The piece _D_, when
cool, is contracted sufficiently to leave the passage _B_ open to the
air. When the steam is turned on, the expelled air from the radiator
escapes through _B_ and _C_, but when the steam reaches _D_ the heat
quickly expands the piece and closes the vent.
Most automatic vents require adjusting when put in place and
occasionally need readjustment. The cap _O_, of Fig. 11, may be removed
with a wrench and a screw-driver used to adjust the piece _D_, so as
to shut off the steam when the radiator is filled with steam. The
expanding piece is simply screwed down until the steam ceases to escape.
Fig. 12 is another style of automatic vent, constructed on the same
principle as that of Fig. 11, but probably more positive in action. In
this vent the part _A_ attaches to the radiator. The expanding portion
_B_ is made in the form of a hollow cylinder, through which the air and
steam escape to the atmosphere. It is longer than the corresponding
piece in the other vent and is more sensitive because of its greater
length and exposed surface. As the piece _B_ elongates from expansion,
the upper end makes a joint with the conical piece _D_. The shape of
this latter piece gives better opportunity for a tight joint than in
the other form of vent and in practice gives better service.
Fig. 13 is a cross-section of the Allen vent. This is an example of a
vent which depends for its action on a float. Whenever sufficient water
accumulates in the body of the vent to raise the float, it closes the
vent by means of its buoyancy. The body of the vent shown in Fig. 13 is
composed of two concentric cylinders. The float _E_ occupies the inner
cylinder, while surrounding it is the outer cylinder _D_. The outer
cylinder is entirely closed except a little hole at _G_. The float is
made of light metal and fits loosely in the inner cylinder. The steam
from the radiator condenses in the vent until the inner cylinder is
filled with water, up to the opening _A_. The float by its buoyancy
keeps the opening in _B_ stopped, and no steam can escape. The air of
the outer cylinder _D_ is expanded by the heat of the steam and most
of the air escapes through the hole _G_. When the radiator cools,
the rarefied air in _D_ contracts and draws the water from the inner
cylinder into the space _D_; this allows the float to fall and unstop
the opening in _B_. When the steam again reaches the vent, the heat
expands the air in _D_ and forces the water into the inner cylinder;
the float is again raised and stops the opening in _B_.
Many other air vents are in common use but most of them operate on
one or the other of the principles described. Fig. 11 is a relatively
inexpensive vent, while Fig. 12 is higher-priced.
[Illustration: FIG. 14.--Steam radiator valve.
FIG. 15.--Sectional view of a steam radiator valve.]
=Steam Radiator Valves.=--Like most other mechanical appliances that
are extensively used, radiator valves are made by a great number
of manufacturers and in many different forms. Some possess special
features that are intended to increase their working efficiency but the
type of radiator valve most commonly used for ordinary construction is
that illustrated in Figs. 14 and 15. It is a style of _angle valve_
that takes the place of an elbow and being made with _a union joint_,
also furnishes a means of disconnecting the radiator without disturbing
the pipes. Fig. 14 is an outside view of the valve and Fig. 15 shows
its mechanical construction. The part _B_ screws onto the end of the
steam pipe and _A_ connects with the radiator. The part _C-D_ is the
_union_. The nut _C_ screws onto the valve and makes a steam-tight
joint at _D_, between the parts. In case it is desired to remove the
radiator, it furnishes an easy means of detaching the valve. The
composition valve-disc _E_ makes a seat on the brass ring directly
under it, to shut off the steam. In case the valve leaks, the disc may
be removed by taking the valve casing apart at _G_. The worn disc can
then be replaced with a new one which may be obtained from the dealer
who furnished the valve. The only moving part of the valve exposed to
the air is at the point where the valve-stem _S_ enters the casing. The
joint is made steam-tight by the packing _P_. The packing is greased
candle wicking that is wound around the stem and held tightly in place
by the screw-cap _H_. If the valve leaks at this joint, a turn or two
with a wrench will stop the escape of the steam.
THE HOUSE-HEATING STEAM BOILER
House-heating boilers were formerly made of sheet metal and are still
so constructed to some extent, but by far the greater number are now
made of cast iron. Sheet-metal boilers are constructed at the factory,
ready to be installed, but the cast-iron type is made in sections
and assembled to make a complete boiler, at the time the plant is
erected. Sectional boilers are convenient to install, on account of the
possibility of handling the parts in a limited space, that would not
admit an assembled boiler without tearing down a part of the basement
for admission.
Cast-iron boilers as commonly used for heating dwellings are made in
two definite styles. The small sizes are cylindrical in form and are
used for either steam or hot-water heating. The larger sizes are made
as illustrated in Figs. 16 and 17, the former being an outside view,
and the latter showing the internal arrangement of the same boiler. The
fire-box, water space and smoke passages are easily recognized. Each
division represents a separate section which assembled as that in the
figures makes a complete boiler with a common opening as shown at the
top of Fig. 17. These boilers are used for residences of large size and
for buildings of less than 10,000 feet of radiating surface. For large
buildings, the steam is most commonly generated in boilers built for
high pressure.
In small plants, intended for either steam or hot-water heating,
the cylindrical style of boiler shown in Fig. 18 is commonly used.
As constructed by different manufacturers, the parts differ quite
materially but Fig. 18 shows all of the essential features and serves
to illustrate the different working parts. The sections into which the
boiler is divided are indicated on the left-hand side of the figure by
the numbers 1 to 6. The parts from 1 to 5 are screwed together with
threaded nipples, joining the central column. The part 6 contains the
grate and the ash-pit, with the draft and clean-out doors.
[Illustration: FIG. 16. FIG. 17.
FIG. 16.--Sectional cast-iron boiler for steam or hot-water heating.
FIG. 17.--Interior view of the boiler shown in Fig. 16.]
The drawing shows the boiler cut through the middle lengthwise and
exposes to view all of the essential features. The fire-box and the
spaces occupied by the steam and water are easily recognized. It will
be seen that the water space surrounds the fire-box except at the
bottom and that the space above the fire-box presents a large amount
of heating surface to the flame and heated gases as they pass to the
chimney. The arrows show their course; first through the openings near
the center, then through those further away. The object being to keep
the heat as long as possible in contact with the heating surfaces
without interfering with the draft.
[Illustration: FIG. 18.--Sectional view of the cylindrical type of
cast-iron, sectional boiler.]
There is no standard method of rating the heating capacity of boilers
of this kind and as a consequence, boilers of different makes--for the
same rating--are not the same in actual heating capacity. The boilers
are sold by their makers in sizes that are intended to furnish heat
sufficient to supply a definite number of square feet of radiating
surface. The ratings are quite generally too high for the weather
conditions of the Northwest. A common practice with contractors is to
select boilers for a given plant 50 per cent. and even 100 per cent.
larger than those rated by the manufacturers for the same amount of
radiation. Some manufacturers sell their boilers at honest ratings but
they are exceptions.
In specifying the capacity of a house-heating plant it is common
practice to require the boiler to be of such size as will easily heat
a definite number of square feet of radiating surface. The radiators
are required to possess sufficient radiating surface to keep the house
at 70°F. in any weather. In the absence of any rules or specifications
for determining the heating capacity of the boiler, the only means
of securing a satisfactory plant is to require a guarantee of the
contractor to install a boiler such as will fulfil the conditions
stated above.
=Boiler Trimmings.=--Attached to the boiler and required for its safe
operation are a number of appliances that demand special attention. The
office of each part should be thoroughly appreciated and the mechanical
construction should be fully understood. An intimate acquaintance with
the details of the plant, helps to make its operation satisfactory and
adds to the efficiency with which it can be made to perform its duty.
=The Water Column.=--In Fig. 18 the water column is shown at _C_.
It is attached to the boiler by pipes at points above and below the
water line, so as to allow a free passage of the water of the boiler
to the interior. The water line should be 3 or 4 inches above the top
heating surface. Attached to the water column is the _gage-glass_, the
_try-cocks_ _T_ and _T_ and the _steam gage_ _G_.
The object of the gage-glass is to show the height of the water in the
boiler. It is shown in place on the boiler in Figs. 16 and 18 and in
detail in Fig. 19. The lower part of the gage-glass occupies a position
on the boiler about 2 inches above the top heating surface. When the
boiler is working, the level of the water should always be visible in
the glass and should stand normally one-third to one-half full.
[Illustration: FIG. 19.--The water gage.]
The water gage is attached to the water column by two brass valves
_V_. The valves are provided so that in case the water glass should
be broken the openings may be closed. The ends of the glass are made
tight by “stuffing-boxes” marked _C_, in the figure. The packing _S_ is
generally in the form of rubber rings but greased wicking may be used
if necessary as in the case of valve-stems.
_The try-cocks_ _T_ and _T_ (Fig. 18) are also intended to indicate
the approximate height of the water in the boiler and should the
water glass be broken may be used in its place. The openings of the
try-cocks point toward the floor. When a cock is opened, should steam
alone escape, it will be absorbed by the air, but if water is escaping,
although much of it will be vaporized and look like steam, some of
the water will be carried to the floor and produce a wet spot. When
the cock is opened wide the escaping water from the lower cock should
always wet the floor.
_The drip-cock_ _P_ (Fig. 18) at the bottom of the gage-glass is for
draining the water column and for blowing out any deposit that may
collect in the opening of the column. This cock should be opened
occasionally to assure the correctness of the gage-glass.
[Illustration: FIG. 20.--Typical Bourdon pressure gage with the face
removed.]
=The Steam Gage.=--Steam pressure is measured in pounds to the
square inch above the pressure of the atmosphere. The gages used for
indicating the pressure of the steam are made in several forms but
the type most commonly used is that shown in Fig. 20. It is known as
the Bourdon type of gage and takes its name from the bent tube _A_,
which furnishes its active principle. The Bourdon barometer invented
in 1849 employed this form of sensitive tube. In the drawing the face
of the gage has been removed to show the working parts. The sensitive
part is the flat elastic tube _A_, which is bent in the form of a
circle. When the pressure of the steam enters at _S_ the air in the
tube is compressed and the tube tends to straighten. The movement of
the tube caused by the steam pressure is communicated to the pointer
by a link connection and gear as shown in the drawing. The amount of
straightening of the tube will be in proportion to the steam pressure
and is indicated by the numbers marked on the face of the gage. When
the pressure is released, the tube returns to its original position
and the spiral spring _C_ turns the hand back to its first position.
[Illustration: FIG. 21.--Cross-section of a pop valve.]
=The Safety Valve.=--All steam boilers should be provided with safety
valves as a safeguard against excessive steam pressures. Of the various
types of safety valves, that known as the _pop-valve_ is most commonly
used on house-heating boilers. It is indicated at _W_ in Fig. 18 and
is shown in section in Fig. 21. The part _A_ is screwed into the top
of the boiler at any convenient place. The pressure of the spring _C_
holds the valve _B_ on its seat until the internal pressure reaches a
certain intensity at which the valve is set, when it opens and allows
the excess steam to escape. When the pressure is reduced, the spring
forces the valve back on its seat. The handle _D_ permits the valve to
be lifted at any time as an assurance that it is in working order. This
should be done occasionally, as the valve may stick to the seat after
long standing and allow the pressure to rise above the point at which
it should “pop.”
The valve may be set to “blow off” at any desired pressure by the
adjusting piece _E_. House-heating boilers generally have their safety
valves set to blow off at 8 or 10 pounds.
=The Draft Regulator.=--As a means of automatic control of the steam
pressure, the draft regulator is frequently used to so govern the fire
that when a certain steam pressure is reached, the direct draft will
be automatically closed and the check-draft damper opened. The draft
regulator is shown in place at _D_ in Fig. 18, and will also be found
in Fig. 16. A detailed description of the regulator will be found on
pages 60 and 61.
RULE FOR PROPORTIONING RADIATORS
Rules for determining the amount of radiating surface that will
be required to satisfactorily heat a building to 70°F. regardless
of weather conditions are entirely empirical, that is, they are
derived from experience. It is evident that no definite rule can
be established that will take into account the method of building
construction, the kind and amount of materials that make up the walls
and the quality of workmanship employed. These variable quantities
coupled with the changing climatic conditions of temperature and wind
velocity produce a complication that cannot be overcome in a formula
that will give exact results.
Many rules are in use for this purpose, no two of which give exactly
the same results when applied to a problem. A common practice is to
apply one of the rules in use and then under conditions of exceptional
exposure, to add to the amount thus calculated as experience may
dictate.
The following rule by Professor R. G. Carpenter of Cornell University
was taken from a handbook published by the J. L. Mott Iron Works of New
York. This company manufactures and deals in all kinds of apparatus
entering into steam and hot-water heating and the rule is given as one
that has produced satisfactory results.
RULE.--Add the area of the glass surface in the room to one-quarter
of the exposed wall surface, and to this add from one-fifty-fifth
to three-fifty-fifths of the cubical contents (one-fifty-fifth for
rooms on upper floor, two-fifty-fifths for rooms on first floor and
three-fifty-fifths for large halls); then for steam multiply by 0.25,
and for hot water by 0.40.
_Example._--A room 20 by 12 by 10 feet with glass exposure of 48 feet,
1/4 of wall exposure (two sides exposed) 320 feet = 80, 1/55 of 2400 =
44.
48 + 80 + 44 = 172 × 0.25 = 43 feet.
If you add 2/55 the surface would be 54 feet.
If you add 3/55 the surface would be 65 feet.
PROPORTIONING THE SIZE OF MAINS
For any size system of steam or water heating the following rule will
be found entirely satisfactory for mains 100 feet long; for each 100
feet additional use a size larger ratio.
RULE.--
_r_ = (3.1416/_d_)_R_ = _a_/_r_ × 100.
_r_ represents ratio of main in inches for each 100 feet of surface;
_d_, diameter of pipe; _R_, quantity of radiation carried by size of
pipe; _a_, area of pipe in inches.
From this the following table has been constructed:
---------+---------+----------+-----------------
Diameter | Area | Ratio to | Quantity of
of pipe | of pipe | each 100 | radiation, steam
| | feet of | or water, on a
| | surface | given size pipe
---------+---------+----------+-----------------
1½ | 1.767 | 2.10 | 84
2 | 3.141 | 1.57 | 200
2½ | 4.908 | 1.25 | 400
3 | 7.069 | 1.04 | 700
3½ | 9.621 | 0.90 | 1,062
4 | 12.566 | 0.78 | 1,590
4½ | 15.904 | 0.70 | 2,272
5 | 19.625 | 0.63 | 3,120
6 | 28.274 | 0.52 | 5,440
7 | 38.484 | 0.45 | 8,550
8 | 50.265 | 0.40 | 12,556
9 | 63.617 | 0.35 | 18,100
10 | 78.540 | 0.30 | 25,300
---------+---------+----------+-----------------
FORMS OF RADIATORS
Radiators are much the same in appearance for both steam and hot-water
heating. They are hollow cast-iron columns so designed that they may
be fastened together in units of any number of sections. The sections
are made in size to present a definite number of square feet of outside
surface that is spoken of as radiating surface. The amount of radiating
surface in any radiator depends on its height and the contour of the
cross-section. The radiator sections may be made in the form of a
single column as Fig. 22 or they may be divided into two, three, four
or more columns to increase their radiating surface.
The following table, taken from a manufacturer’s catalogue, shows the
method of rating the heating capacity of a particular design. In the
table, the first column gives the number of sections in the radiator,
the second column states the length of the radiator in inches. The
columns headed heating surface give the heights of the sections in
inches and the amount of radiating surface in various radiators of
different heights and numbers of sections. As an example: This table
refers to the three-column radiators of Fig. 23. Such a radiator 32
inches high with 10 sections would contain 45 square feet of radiating
surface and would be 25 inches in length.
--------+--------+----------------------------------------------------
| | Heating surface--square feet
| +--------+--------+--------+--------+--------+-------
No. | Length | 45 in. | 38 in. | 32 in. | 26 in. | 23 in. | 20 in.
of | 2½ in. | high, | high, | high, | high, | high, | high,
sections| per | 6 sq. | 5 sq. | 4½ sq. | 3¾ sq. | 3¼ sq. | 2¾ sq.
| section| ft. | ft. | ft. | ft. | ft. | ft.
| | per | per | per | per | per | per
| | sec. | sec. | sec. | sec. | sec. | sec.
--------+--------+--------+--------+--------+--------+--------+-------
2 | 5 | 12 | 10 | 9 | 7½ | 6½ | 5½
3 | 7½ | 18 | 15 | 13½ | 11¼ | 9¾ | 8¼
4 | 10 | 24 | 20 | 18 | 15 | 13 | 11
5 | 12½ | 30 | 25 | 22½ | 18¾ | 16¼ | 13¾
6 | 15 | 36 | 30 | 27 | 22½ | 19½ | 16½
7 | 17½ | 42 | 35 | 31½ | 26¼ | 22¾ | 19¼
8 | 20 | 48 | 40 | 36 | 30 | 26 | 22
9 | 22½ | 54 | 45 | 40½ | 33¾ | 29¼ | 24¾
10 | 25 | 60 | 50 | 45 | 37½ | 32½ | 27½
11 | 27½ | 66 | 55 | 49½ | 41¼ | 35¾ | 30¼
12 | 30 | 72 | 60 | 54 | 45 | 39 | 33
13 | 32½ | 78 | 65 | 58½ | 48¾ | 42¼ | 35¾
14 | 35 | 84 | 70 | 63 | 52½ | 45½ | 38½
15 | 37½ | 90 | 75 | 67½ | 56¼ | 48¾ | 41¼
16 | 40 | 96 | 80 | 72 | 60 | 52 | 44
17 | 42½ | 102 | 85 | 76½ | 63¾ | 55¼ | 46¾
18 | 45 | 108 | 90 | 81 | 67½ | 58½ | 49½
19 | 47½ | 114 | 95 | 85½ | 71¼ | 61¾ | 52¼
20 | 50 | 120 | 100 | 90 | 75 | 65 | 55
21 | 52½ | 126 | 105 | 94½ | 78¾ | 68¼ | 57¾
22 | 55 | 132 | 110 | 99 | 82½ | 71½ | 60½
23 | 57½ | 138 | 115 | 103½ | 86¼ | 74¾ | 63¼
24 | 60 | 144 | 120 | 108 | 90 | 78 | 66
25 | 62½ | 150 | 125 | 112½ | 93¾ | 81¼ | 68¾
26 | 65 | 156 | 130 | 117 | 97½ | 84½ | 71½
27 | 67½ | 162 | 135 | 121½ | 101¼ | 87¾ | 74¼
28 | 70 | 168 | 140 | 126 | 105 | 91 | 77
29 | 72½ | 174 | 145 | 130½ | 108¾ | 94¼ | 79¾
30 | 75 | 180 | 150 | 135 | 112½ | 97½ | 82½
31 | 77½ | 186 | 155 | 139½ | 116¼ | 100¾ | 85¼
32 | 80 | 192 | 160 | 140 | 120 | 104 | 88
--------+--------+--------+--------+--------+--------+--------+-------
Fig. 22 is a radiator made up of eight single-column sections. In Fig.
23 is shown five three-column radiators, varying in height from 20 to
45 inches.
The sections of steam radiators are joined together at the bottom
with _close-nipples_, so as to leave an opening from end to end. The
sections of hot-water radiators are joined in the same manner, except
that there is an opening at both top and bottom. Fig. 30 shows the
openings of a hot-water radiator installed as _direct-indirect_ heater.
Fig. 24 illustrates a special form of radiator that is intended to be
placed under windows and in other places that will not admit the high
form. Such a radiator as that shown in the picture is often covered
with a window seat and in cold weather becomes the favorite place of
the sitting room. Another special form is that of Fig. 25. As a corner
radiator this style is much to be preferred to the ordinary method of
connection; here the angle is completely filled--there is no open space
in the corner.
[Illustration: FIG. 22. FIG. 23.
FIG. 22.--Single column steam radiator.
FIG. 23.--Three-column radiators of different heights; for steam or
hot-water heating.]
Wall radiators such as shown in Fig. 26 are made to set close to the
wall, where floor space is limited. They are particularly adapted for
use in narrow halls, bathrooms and other places where the ordinary type
could not be conveniently used.
A radiator that will appeal to all neat housekeepers is that of Fig.
27. It does not stand on the floor as in the case of the ordinary
type, but is hung from the wall by concealed brackets. The difficulty
of sweeping under this radiator is entirely avoided.
Fig. 28 is a radiator designed to furnish a warming oven for plates and
for heating the room at the same time. It is sometimes installed in
dining rooms.
[Illustration: FIG. 24.--Six-column, low form of hot-water radiators to
be placed under windows.]
[Illustration: FIG. 25.--Two-column corner radiator for steam heating.]
[Illustration: FIG. 26.--Wall form, radiator for steam or hot water.]
The ordinary method of heating by the use of radiators is known as the
_direct_ method. The air is heated by coming directly into contact with
the radiators and distributed through the room by convection. If the
arrangement is such that the air is brought from outdoors and heated
by the radiator before entering the room, it is called the _indirect_
method of heating. Such an arrangement is illustrated in Fig. 29. The
radiator is located beneath the floor, in a passage that takes the
air from outdoors and after being heated, enters the room through a
register located in the wall.
Fig. 30 is still another arrangement known as the _direct-indirect_
method of heating. The radiator is placed in position, as for direct
heating, but the air supply is taken from outdoors. The radiator base
is enclosed and a double damper _T_ regulates the amount of air that
comes from the outside. When the inside damper is closed and the
outside damper is open, as is shown in the drawing, the air comes from
outdoors and is heated as it passes through the radiator on its way to
the room. If the dampers are reversed, the air circulates through the
radiator as in the case of direct radiation.
[Illustration: FIG. 27.--Two-column radiator suspended from the wall by
brackets.]
[Illustration: FIG. 28.--Dining-room radiator containing a warming
oven.]
In the use of the _direct_ or the _direct-indirect_ method of heating
the principal object to be attained is that of ventilation, but quite
generally the passages are so arranged that the air may be taken from
outdoors or, if desired, the air of the house may be sent through the
radiators to be reheated. In extremely cold and windy weather it is
sometimes difficult to keep the house at the desired temperature when
all of the air supply comes from the outside. Under such conditions the
outside air is used only occasionally. In mild weather it is common to
use the outdoor air most of the time. The cost of heating, when these
methods are used, is higher than by direct radiation, because the air
is being constantly changed in temperature from that of the outside to
70°.
[Illustration: FIG. 29.--Ventilation by the indirect method of heating.]
[Illustration: FIG. 30.--Ventilation by the direct-indirect method of
heating.]
=Radiator Finishings.=--In steam and hot-water heating the decoration
of the radiators is a much more important item than that of a
good-looking surface or one which will harmonize with the setting.
Until recently radiator finishing has been considered a minor detail
and the familiar bronze has been looked upon as a standard covering,
while painted radiators were considered only a matter of taste. The
character of the surface is, however, the determining factor in the
quantity of heat given out by radiators. This has been determined in
the experimental laboratory of the University of Michigan by Professor
John A. Allen. Comparison was made of bare cast-iron radiators with
the same forms painted as indicated in the following table. The bare
radiator was taken at 100 per cent.; the other finishes are expressed
in per cent. above or below that of the bare radiator.
Condensing
capacity,
per cent.
No. 1, a cast-iron radiator, bare as received from the foundry 100
No. 2, a cast-iron radiator, coated with aluminum bronze 78
No. 3, a cast-iron radiator, three coats of white enamel paint 102
No. 4, a cast-iron radiator, coated with copper bronze 80
No. 5, a cast-iron radiator, three coats of green enamel paint 101
No. 6, a cast-iron radiator, three coats of black enamel paint 101
The author has stated further that, “It might be said in general that
all bronzes reduce the heating effect of the radiator about 25 per
cent. while lead paints and enamels give off the same amount of heat
as bare iron. The number of coats of paint on the radiator makes no
difference. The last coat is always the determining factor in heat
transmission.”
PIPE COVERINGS
All hot-water or steam pipes in the basement and in other places not
intended to be used for heating should be covered with some form of
insulating material. At ordinary working temperature a square foot of
hot pipe surface will radiate about 15 B.t.u. of heat per minute. To
prevent this loss of heat and the consequent waste of fuel the pipes
should be covered with some form of insulating material.
Pipe coverings are made of many kinds of material and some possess
insulating properties that may reduce the loss to as low a point as 15
per cent. of the amount radiated by a bare pipe. Many good insulating
materials do not give satisfactory results as pipe coverings because
they do not keep their shape, some cannot be considered in the average
plant because of high cost.
Wood-pulp paper is extensively used as a cheap covering; it is a good
insulator and under ordinary conditions makes a satisfactory covering.
A more efficient and also a more expensive covering that is extensively
used is that made of magnesia carbonate and known as magnesia covering.
Aside from these, other forms made of cork, hair-felt, asbestos and
composition coverings are sometimes used in house-heating plants.
In selecting a pipe covering, there should be taken into account not
only its insulating properties but its ability to resist fire, dampness
or breeding places for vermin. It rests entirely with the owner whether
he covers the pipes with a combustible or an incombustible material
when the insulating properties are about the same. Coverings made of
animal or vegetable materials under some conditions furnish a breeding
place for vermin.
Pipe coverings are made in sections about 3 feet in length and from 1
to 1-3/8 inches in thickness. The sections are usually cut in halves
lengthwise to permit being put in place. The sections are covered with
common muslin to keep the material in place and sometimes are painted
after being installed. Painting has nothing to do with their insulating
capabilities, but it preserves the cloth and makes a neat appearance.
The sections when put in place are secured by pasting one of the loose
edges of the cloth to the surface. The ends of the sections are bound
together with strips of metal. Fig. 31 shows the appearance of the pipe
when the covering is in place.
[Illustration: FIG. 31.--Pipe covering.]
Irregular surfaces like the body of the furnace, pipe connections,
etc., are insulated by coverings made from a plaster that is made
expressly for such work. It is known as asbestus plaster. The plaster
may be purchased in bulk and put in place with a trowel. As it is found
in the market the plaster requires only the addition of water to put
into working form.
The value of a pipe covering is not in proportion to its thickness.
Experiments with pipe coverings have shown that a thickness of 1-3/8
inches will reduce the radiation 90 per cent., but doubling the
thickness reduces the loss only 5 per cent. It, therefore, does not pay
to make a covering more than 1-3/8 inches thick.
=Vapor-system Heating.=--This system of heating is not greatly
different from the steam plants already described but it is operated
under conditions which do not permit the steam in the boiler to rise
beyond a few ounces of pressure. Since the plant is intended to work
at a pressure that is scarcely indicated by an ordinary steam gage, it
has been termed a _vapor system_ to distinguish it from the pressure
systems which employ steam, up to 5 pounds or more to the square inch.
The heat is transmitted to the radiators in the same manner as in the
pressure systems. The heat of vaporization of steam is somewhat greater
at the boiling point of water than at higher pressures, and the lack
of pressure, therefore, increases its heating capacity. This is shown
in the table, properties of steam, on page 3. The successful operation
of such a plant rests in the delivery of the vapor to the radiators at
only the slightest pressure and the return of the condensate to the
boiler without noise or obstruction to the circulation at the same time
ejecting the contained air.
The excellence of the system depends in the greatest measure on good
design and the employment of special facilities that allow all water
to be discharged from the radiators and returned to the boiler without
accumulation at any part of the circulating system. It requires,
further, the discharge of the air from the system at atmospheric
pressure. The system is, therefore, practically pressureless.
Various systems of vapor heating are sold under the names of their
manufacturers. Each possesses special appliances for producing positive
circulation that are advocated as features of particular excellence.
The vapor system of heating has met with a great deal of favor as a
more nearly universal form of heating than either the pressure-steam
plant or the hot-water method of heating.
Fig. 31_a_ is a diagram illustrating the C. A. Dunham system of
vapor heating. It will be noticed that there are no air vents on the
radiators. The air from the radiators is ejected through a special
form of trap that is indicated in the drawing. These traps permit
the water and air to pass from the radiators but close against the
slightly higher temperature of the vapor. This assures the condensation
of the vapor in the radiators and excludes it from the return pipes.
The water returns to the boiler in much the same manner as in the
pressure systems already described but the air escapes through the air
eliminator as indicated in the drawing. The system is, therefore, under
atmospheric pressure at this point and only a slight amount greater in
the boiler.
[Illustration: FIG. 31_a_.--Diagram showing the C. A. Dunham Co.’s
system of vapor heating.]
The water of condensation is returned to the boiler against the vapor
pressure, by a force exerted by the column of water in the pipe
connecting the air eliminator with the boiler. The main return is
placed 24 inches or more above the water line of the boiler. It is the
pressure of this column that forces the water into the boiler through
the check valve, against the vapor pressure in the boiler.
It might be imagined that the water in the boiler and that in the
air-eliminator pipe formed a “U-tube,” the vapor pressure on the water
surface in the boiler, and the atmospheric pressure on the water in
the eliminator standpipe. The slight vapor pressure in the boiler is
counterbalanced by a column of water in the eliminator pipe. It is this
condition that fixes a distance of 24 inches from the water line to the
return pipe; that is, the force exerted by a column of water 24 inches
high is required to send the water into the boiler.
The vapor pressure is controlled by means of the pressurestat, which
is an electrified Bourdon spring pressure gage, connected up by
simple wiring to the damper motor, which may be any form of damper
regulator. In residential work, the pressurestat is so connected with a
thermostat, that both pressure and temperature conditions operate and
control this damper regulator, which in turn controls the draft and the
fire.
The two instruments are so connected that if the pressure mounts to 8
ounces and the pressurestat caused the draft damper to close and the
check to open, the thermostat cannot reverse the damper, regardless
of the temperature in the room, until the pressure drops below the
limiting 8-ounce pressure. Just so long as the pressure is below 8
ounces, the thermostat is the master in the control of the dampers.
The minute that the pressure goes up to 8 ounces then the pressurestat
takes control.
CHAPTER II
THE HOT-WATER HEATING PLANT
Of the various systems of heating dwellings that by hot-water is
considered by many to be the most satisfactory. On account of its high
specific heat, water at a temperature much below the boiling point
furnishes the heat necessary to keep the temperature of the house at
the desired degree. The temperature of the radiators is generally much
lower than those heated by steam but the amount of radiating surface
is greater than for steam heating plants of the same capacity. It is
because of the relatively low temperature at which the water is used,
that the greater amount of heating surface is required.
One objection to the use of hot water as a means of heating is, that
once the heat of the house is much reduced, the furnace is a long time
in raising the temperature to normal. This is due to the fact that the
temperature of the water of the entire system must be uniformly raised,
because of its continuous passage through the heater. On the other
hand, this uniformity of the temperature of the water prevents sudden
changes in the temperature of the house. Water-heating plants work with
perfect quiet and may be so regulated to suit the outside temperature
that the heat of the water will just supply the amount to suit the
prevailing conditions.
The care required in the management of the boiler is less than that
required in the steam plant because of the fewer appliances necessary
for its safe operation. Another advantage in the use of the hot-water
plant is its adaptability to the temperature conditions during the
chilly weather of early fall and late spring, when a very small amount
of heat is required. At such times the temperature of the radiators is
but a few degrees warmer than the outside air. The amount of attention
necessary for maintaining the proper furnace fire under such conditions
is less then for any other form of heating. The increasing use of the
hot-water plant for heating the average-sized dwelling attests to its
excellence in service.
=The Low-pressure Hot-water System.=--A hot-water system consists of a
heater, in which the water receives its supply of heat, the circulating
pipes for conducting the heated water to and from the radiators that
supply heat to the rooms, and the expansion tank that receives the
excess of water caused when the temperature is raised from normal to
the working degree. In addition to the parts named there are a number
of appliances to be described later, that are required to make the
system complete.
[Illustration: FIG. 32.--Diagram of a simple form of hot-water heating
plant.]
A hot-water plant of the simplest form is shown in Fig. 32. The
illustration presents each of the features mentioned above, as in a
working plant. The different parts are shown cut across through the
middle, the black portion representing water. Not only does the water
fill the entire system but appears in the expansion tank when the plant
is cold.
Hot-water heaters are quite generally in the form of internally fired
boilers. The fire-box occupies a place inside the boiler and is
surrounded, except at the bottom, by the water space. Commonly, these
boilers are made of cast iron and are constructed in sections, the
same as the steam boiler shown in Fig. 16. Manufacturers sell a single
style for either steam or hot-water heating. The boiler in Fig. 32 is
cylindrical in form. It is made of wrought iron and contains a large
number of vertical tubes through which the heat from the furnace must
pass on its way to the chimney.
As the water is heated it expands and rises to the top of the boiler
because of its decreased weight. Since the water in the radiator is
really a part of the same body of water, the heated portion rises
through the supply pipe to the top of the radiator. As the hot water
rises in the radiator, it displaces an equal amount of cold water,
which enters the boiler at the bottom. This displacement is constant
and produces a circulation that begins as soon as the fire is started
and varies with the difference in temperature between the hot water
leaving the boiler at the top and the cold water entering at the bottom.
As the water in the system is heated and expands, there must be some
provision made to receive the enlarging volume. In this arrangement a
pipe connects the bottom of the boiler with the expansion tank located
at a point above the radiator. Under the conditions represented in
the drawing the water does not circulate through the tank and as a
consequence the water it contains is always cold.
In raising its temperature, water absorbs more heat than any other
fluid and on cooling it gives up an equal amount. As a consequence
it furnishes an excellent vehicle for transmitting the heat of the
furnace to the rooms to be heated. Water, however, is a poor conductor
and receives its heat by coming directly into contact with the hot
surfaces of the furnace, and gives it up by direct contact with the
radiator walls. To transmit heat rapidly and maintain a high radiator
temperature, the circulation of the water in the system must be
the best possible. The connecting pipes between the boiler and the
radiators must be as direct as circumstances will permit and the amount
of radiating surface in each room must be sufficient to easily give up
an ample supply of heat. Even though the furnace is able to furnish a
plentiful supply of heat to warm the house, it cannot be transmitted to
the rooms unless there is sufficient radiating surface. A plant might
prove unsatisfactory either because of a furnace too small to furnish
the necessary heat or from an insufficient amount of radiating surface.
Yet another factor in the design of a plant is that of the conducting
pipes. Both the boiler and the radiators might be in the right
proportion to produce a good plant, but if the distributing pipes are
too small to carry the water required, or the circulation is retarded
by many turns and long runs, the plant may fail to give satisfaction.
Fig. 33 shows a complete hot-water plant adapted to a dwelling. It
is just such a plant as is commonly installed in the average-sized
house but without any of the appliances used for automatic control of
temperature. The regulation of the temperature is made entirely by
hand, in so governing the fire as to provide the required amount of
heat. In the drawing the supply and return pipes may be traced to the
radiators as in the case of the simple plant. The supply pipe from the
top of the boiler branches into two circuits to provide the water for
the two groups of radiators at the right and left side of the house.
To provide any radiator with hot water, a pipe is taken from the main
supply pipe and passing through the radiator it is brought back and
connected with the return pipe which conducts the water back to the
boiler.
[Illustration: FIG. 33.--The low-pressure hot-water heating system
applied to a small dwelling.]
The expansion tank is located in the bathroom near the ceiling. It is
connected with the circulating system by a single pipe which joins the
supply pipe as it enters the radiator located in the kitchen. Like the
expansion tank in Fig. 31 the water it contains is always cold. It is
provided with a gage-glass which shows the level of the water in the
tank and an overflow pipe which discharges into the bathtub, in case
of an overflow. An overflow pipe must always be provided to take care
of the surplus when the water in the system becomes overheated. This
does not often occur but the provision must be made for the emergency.
The overflow pipe is frequently connected directly with the sewer or
discharged at some convenient place in the basement.
=The High-pressure Hot-water System.=--In the hot-water plant described
the expansion tank is open to the air and the water in the system is
subjected to the pressure of the atmosphere alone. The heat of the
furnace may be sufficiently great to bring the entire volume of water
of the system to the boiling point and cause it to overflow but the
temperature of the water cannot rise much above the boiling point due
to the pressure of the atmosphere.
If the expansion tank is closed, the pressure generated by the
expanding water and the formation of steam will permit the water to
reach a much higher temperature. In the table of temperatures and
pressures of water on page 3, it will be seen that should the pressure
rise to 10 pounds, that is, 10 pounds above the pressure of the
atmosphere, the temperature of the water would be very nearly 240°F.
(239.4°F.). The difference in heating effect in hot-water heating
plants under the two conditions is very marked. In the low-pressure
system the temperature of the radiators cannot be above 212° but the
high-pressure system set for 10 pounds pressure will heat the radiators
to 240°, and a still higher pressure would give a correspondingly
higher temperature. The amount of heat radiated by a hot body is in
proportion to the difference in temperature between the body and
the surrounding air. If we consider the surrounding air at 60° the
difference in amount of heat-radiation capacity of the two radiators
would be as 180 is to 132. The advantage of the high-pressure system
lies in its ability to heat a given space with less radiating surface
than the low-pressure system.
In Fig. 34 is illustrated an application of a simple and efficient
valve arrangement that converts a low-pressure hot-water system into
a high-pressure system without changing in any way the piping or
radiators. The drawing shows the boiler and two radiators connected as
for a low-pressure system, but attached to the end of the pipe as it
enters the expansion tank is a safety valve _B_ and a check valve _A_,
as indicated in the enlarged figure of the valve. The safety valve is
intended to allow the water to escape into the expansion tank when the
pressure in the system reaches a certain point for which the valve is
set. The check valve _A_ permits the water to reënter the system from
the tank whenever the pressure is restored to its normal amount.
[Illustration: FIG. 34.--The high-pressure system of hot-water heating.]
Suppose that such a system is working as a low-pressure plant. The hot
water from the top of the boiler is flowing to the radiators through
the supply pipe and the displaced cooler water is returning to the
bottom of the boiler through the return pipe as in the other plants
described. It is now found that the radiators are not sufficiently
large to heat the rooms to the desired degree except when the furnace
is fired very heavily. It is always poor economy to keep a very hot
fire in any kind of a heater, because a hot fire sends most of its heat
up the chimney. If the radiators could be safely raised in temperature,
they would, of course, give out more heat and as a result the rooms
would be more quickly heated and kept at the required temperature with
less effort by the furnace. The difficulty in this case lies solely in
there being insufficient radiator surface to supply heat as fast as
required.
The increase in radiator temperature is accomplished by the pressure
regulating valve _B_, attached to the end of the pipe as it enters the
expansion tank. The expansion tank with the regulating valve is shown
enlarged at the left of the figure. The valve _B_ is kept closed by
a weight marked _W_, that is intended to hold back a pressure of say
10 pounds to the square inch. A pressure of 10 pounds will require a
temperature of practically 240°F. (see table on page 3). The check
valve _A_ is kept closed by the pressure from the inside of the system.
When the pressure of the water goes above 10 pounds--or the amount of
the weight is intended to hold back--the valve is lifted and an amount
of water escapes through the valve _B_ into the tank, sufficient to
relieve the pressure. Should enough water be forced out of the system
to fill the tank to the top of the overflow pipe, the overflow water is
discharged through this pipe into the sink in the basement.
When the house has become thoroughly warmed, the demand for a high
radiator temperature is reduced, the furnace drafts are closed, the
water in the system cools and as it shrinks the system will not be
completely filled. It is then necessary to take back from the tank the
water that has been forced out by excess pressure. It is here that the
check valve comes into use. So long as there is pressure on the pipes,
this valve is held shut and no water can escape, but as the inside
pressure is released by the cooling there will come a point where the
water in the tank will flow back through the valve _A_ and fill the
system.
This is the type of valve used by the Andrews Heating Co. and
designated a regurgitating valve. In practice it gives excellent
service. The only danger of excessive pressure in the use of this
device is the possibility of the valve becoming stuck to the seat
through disuse. Any possible danger from such an occurrence may be
eliminated by the occasional lifting of the valve by hand.
=Heating-plant Design.=--A heating plant should be designed by a
person of experience. No set of rules has yet been devised that will
meet every condition. Carpenter’s rules given on page 25 serve for hot
water as well as for steam as a means of determining the radiating
surface required for an ordinary building, but the rules do not take
into account the method of construction of the house and the consequent
extra radiation demanded for poorly constructed buildings. In many
cases the designer must rely on experience as a guide where the rules
will not apply. In the case usually encountered, however, the rules
given will meet the conditions.
What was said regarding the size of steam boilers required for
definite amounts of heating surfaces, applies with equal force to
hot-water boilers, because house-heating boilers are commonly used
for either steam or hot-water heating. There are no established rules
for determining the heating capacities of house-heating boilers.
Manufacturers’ ratings are usually low. There are some manufacturers
who make honest ratings for their boilers but they are in the minority.
When the heating capacity of a boiler is not known from experience, the
only safeguard against installing a boiler too small for the radiators
to be heated, is to require a guarantee that the plant will give
satisfaction when in operation and when considered necessary a certain
percentage of the contract price should be withheld until the plant
proves itself by actual trial.
=Overhead System of Hot-water Heating.=--In Fig. 35 is illustrated
another system of high-pressure hot-water heating that corresponds to
the overhead system of steam heating. It differs from the high-pressure
system already described in the method of distribution and in the
radiator connections.
The flow pipe is taken to the attic and there joined to the expansion
tank as a point of distribution. On the expansion tank is a safety
valve set at 10 or more pounds pressure. The flow of the water is all
downward toward the radiators. The circulation through the radiators is
also different from the other plants described. The supply pipe joins
directly to the return pipe and the connections to the radiators are
made at the top and bottom of the same end. The circulation through
the radiators in this case is due to the difference in gravitational
effect between the hot and colder water at the top and bottom of the
radiator. The system requires no air vents on the radiators as all
air that might collect in the system goes up to the expansion tank.
The safety valve on the expansion tank in this case is the common
lever type. The overflow should empty into the sewer and be pitched to
prevent any water being retained in the discharge pipe. If water should
be retained in this pipe and should freeze, the system would become
dangerous, because of the possibility of high pressures from a hot fire.
[Illustration: FIG. 35.--The overhead system of hot-water heating.]
=Expansion Tanks.=--Fig. 36 is a form of expansion tank in common use.
It may be used for either the high-or low-pressure system. The body of
the tank is made of galvanized iron and is made to stand a considerable
amount of pressure. The gage-glass is attached at _B_, and the overflow
at _O_. The pipe _E_ connects the tank with the circulating system and
_D_ connects with the cold-water supply as a convenience for filling
the system with water. The object in placing the stop-cock _D_ near
the expansion tank is to avoid overflowing the system in filling. The
overflow pipe, as stated above, is most conveniently connected with the
sewer, into which the water will run in case of an overflow, but the
other methods shown are commonly used. There should be no valve in this
pipe nor in the pipe _E_.
[Illustration: FIG. 36.--The expansion tank.]
[Illustration: FIG. 37.--When the expansion tank of a hot-water heating
system must be so located that it is apt to freeze, it must be piped as
a radiator.]
The expansion tank must be so located that there will be no danger of
freezing. Should it be necessary to place the tank in the attic or
where freezing is possible, the tank must be so connected as to become
a part of the circulating system. Such an arrangement is shown in Fig.
37. The expansion tank is connected with a supply and return pipe as a
radiator. This arrangement is sometimes used but it is not desirable.
It is wasteful of heat and there is always a possibility of freezing
in case the fire in the furnace is extinguished a sufficient time to
allow the water to grow cold.
Any possibility of danger from excessive pressures in either the
low-pressure or the high-pressure system must originate in the
expansion tank. It is, therefore, desired to again mention the
possible causes of danger. Any closed-tank system is liable to become
overheated. The expansive force of water is irresistible and unless
some means is taken to prevent excessive pressure some part of the
apparatus is apt to burst. _No closed-tank system should be used
without a safety valve._
The low-pressure or open-tank system requires no safety appliances. So
long as there is open communication between the tank and the boiler the
pressure cannot rise but slightly above that of the atmosphere. There
is only one cause that will lead to high pressure in such a system. If
the pipe connecting the expansion tank is stopped an excessive pressure
might generate. There is little or no danger of this happening.
In the closed-tank system the expansion tank should be of greater
capacity than for the open-tank system. Its size is commonly about
one-ninth of the volume of water used. The larger tank is necessary
to prevent too rapid rise of pressure as the temperature of the water
rises. The air in the tank acts as a cushion against which the pressure
of the expanding water is exerted.
The extended use of hot-water heating has led to the invention of many
appliances for the improvement of the circulation and heating effects.
Pulsation valves are used for retaining the water in the boiler until
a definite pressure has been attained that will lift the valve long
enough to dissipate the pressure. Many of these systems possess merit
and some of them are great improvements over the simple plant.
=Radiator Connection.=--The method of connecting the radiators to
the distributing pipes depends entirely on local conditions. In a
well-balanced system any of the methods shown in Figs. 38, 39 or 40
might be used with good heating effects. The method of attaching the
supply pipe to the radiator is, however, an important factor in case
of accumulation of air. In Fig. 41 is shown the form of connection
most commonly used. The drawing is intended to represent a cast-iron
radiator with the valve at _D_, and the air vent at _B_. Should air
collect in the radiator it will rise to the top and displace the water.
The water will continue to circulate and heat as much of the radiator
as is in contact with the water, but that part not in contact will
receive no heat from the water and will, therefore, fail to fulfill its
function. As soon as the air vent is opened the air will escape and
allow the water to entirely fill the space.
[Illustration: FIG. 38. FIG. 39. FIG. 40.
FIGS. 38 TO 40.--Various methods of attaching the supply and return
pipes to hot-water radiators.]
[Illustration: FIG. 41.--The effect of accumulation of air in a
hot-water radiator with bottom connections.]
[Illustration: FIG. 42.--With this method of connections, if the
air collects sufficiently to force the water down to the level L,
circulation will stop.]
In Fig. 42 a much different condition exists, when air accumulates. In
this mode of connection the water enters through the valve _V_, and
escapes at the bottom of the opposite end. When air fills the radiator
to the line _L_, the circulation is stopped and the radiator will grow
cold.
The position of the valve on these radiators is of little consequence.
The valve is intended merely to interrupt the flow of the water and may
occupy a place on either end of the radiator with the same result.
=Hot-water Radiators.=--Radiators for hot-water heating are most
commonly of cast iron and in appearance are the same as those used for
steam heating. The only difference in the two forms is in the openings
between the sections. Those intended for steam have an opening at the
bottom joining the sections; while those for hot water have openings at
both top and bottom to permit circulation of the water.
[Illustration: FIG. 43.--The hot-water radiator valve.]
[Illustration: FIG. 43_a_.--Details of construction of the hot-water
radiator valve.]
=Hot-water Radiator Valves.=--Valves for hot-water radiators differ
materially from those used on steam radiators. Figs. 43 and 43a show
the outside appearance and the mechanical arrangement of the parts
of the Ohio hot-water valve. The part _A_ in Fig. 43_a_ is a hollow
brass cylinder attached to the valve-stem, one side of which has been
removed. When it is desired to shut off the supply of heat the handle
of the valve is given one-quarter turn and the part _A_ covers the
opening to the inlet pipe. The supply of water being shut off, the
radiator gradually cools. When the valve is closed a small amount of
water is admitted to the radiator through a 1/8-inch hole in the piece
_A_ to prevent the possibility of freezing.
=Air Vents.=--In the use of the systems of hot-water heating described,
every radiator must be supplied with an air vent of some kind to take
away the trapped air which accumulates through use. Any kind of a valve
will serve as a vent for hand regulation and generally such a cock as
is shown in Fig. 10 is employed.
=Automatic Hot-water Air Vents.=--It is sometimes desired to use
automatic air vents on hot-water radiators. For such work a vent is
used that remains closed as long as water is present and will open when
the water is displaced by the accumulating air, but will again close
when the air is discharged. In such vents the valve is controlled by
a float, the buoyancy of the float when surrounded by water serving
to keep the valve closed. These vents are not so positive in their
action as automatic air vents for steam. The change in temperature
which controls the steam vent does not take place with hot water. The
automatic hot-water vents are not perfectly reliable. They may work
with entire satisfaction for a long time and then fail from very slight
cause. The failure of a hot-water vent is generally discovered by
finding a pool of water on the floor or a wet spot on the ceiling or
wall of the floor below.
[Illustration: FIG. 44.--Automatic air vent for hot-water radiators.]
One type of the automatic hot-water vent that has proven quite
successful is shown in Fig. 44. The threaded lug is screwed into the
radiator at the proper point. As the water enters the radiator the air
is discharged through the vent, escaping at the opening _C_. When the
water has risen to a sufficient height it enters the openings _G_ and
_H_ until enough is present to raise the float _A_. The pointed stem
attached closed the hole _C_ with sufficient force to make an air-tight
joint. The float _A_ is a very light copper cylinder. Its buoyancy
supplies the force to close the vent and its weight opens the vent when
the water is displaced by air. It will be readily seen that very slight
cause might prevent the performance of its duty.
CHAPTER III
THE HOT-AIR FURNACE
Of the methods of heating dwellings other than by stoves, that of the
hot-air furnace is the most common. Of the various modes of furnace
heating it is the least expensive in first cost and most rapid in
effect. In the use of steam heat, the water in the boiler must be
vaporized before its heat is available. With hot-water heating, the
whole mass of water in the entire system must be raised considerably in
temperature before its heat can affect the temperature of the rooms,
and consequently in first effect it is very slow. In the use of the
hot-air furnace the heat from the register begins to warm the rooms
when the fire is started.
Hot-air furnaces are made by manufacturing companies in a great variety
of styles and forms to suit purposes of every kind. In practice the
furnace is built in sizes, to heat a definite amount of cubical space.
The maker designs a furnace to heat a certain number of cubic feet of
space contained in a building. It must be sufficiently large to keep
the temperature at 70°F. on the coldest nights of winter when the
wind is blowing a gale. It is evident that with the variable factors
entering the problem, the designer must be a person of experience in
order that the furnace meet the requirements.
The following table taken from a manufacturer’s catalogue shows the
method of adapting the product of the maker to any size of dwelling.
The volume of the house is calculated in cubic feet and from this
result the size of furnace most nearly suited is selected from the
table.
------------------------+--------+--------+--------+--------+--------
Furnace number | 1 | 2 | 3 | 4 | 5
------------------------+--------+--------+--------+--------+--------
Weight without casing, | 984 | 1,111 | 1,340 | 1,531 | 1,934
lb. | | | |
------------------------+--------+--------+--------+--------+--------
Estimated capacities in | 8,000 | 12,000 | 20,000 | 35,000 | 60,000
cubic feet | to | to | to | to | to
| 12,000 | 20,000 | 35,000 | 60,000 |100,000
------------------------+--------+--------+--------+--------+--------
Capacity in number of | | | | |
rooms of ordinary size | 3 to 5 | 5 to 7 | 7 to 9 |9 to 12 |12 to 15
in residence heating | | | | |
------------------------+--------+--------+--------+--------+--------
CONSTRUCTION
[Illustration: FIG. 45.--Interior view of a hot-air furnace.]
The furnace, in general construction, consists of a cast-iron fire-box
with its heating surfaces, through which the flames and heated gases
from the fire pass, on the way to the chimney; these with the passages
and heating surfaces for heating the air compose the essential
features. Fig. 45 shows such a furnace with the sides broken away to
show the internal construction. The flames and gases from the fire-box
_F_ circulate through the cast-iron drum _D_ and are discharged at _C_
to the chimney. The drum _D_ is made in such form that it presents to
the heat from the fire a large amount of heating surface and at the
same time offers as little opposition as possible to the furnace draft.
The air to be heated enters the furnace through the cold air duct at
the bottom, and after circulating through the drum, passes out at
the openings _R_ to the conducting pipes. The cast-iron box _W_ is a
water tank that should be attached to every hot-air furnace. The water
contained in the tank is for humidifying the air as it passes through
the furnace. In this furnace the outside casing is of sheet iron,
reinforced with wrought-iron flanges. The front, which contains the
doors of the fire-box, ash-pit, etc., are of cast iron of ornamented
design.
As the air to be heated passes through the furnace it receives part of
its warmth by radiation but most of it is absorbed by coming directly
into contact with the heating surfaces. Since air is a poor conductor
of heat its temperature is raised very slowly; it should, therefore,
be kept in contact with the heating surfaces as long as possible to
insure an economical furnace. In common practice the ratio of heating
surface to grate surface average 35 to 1; that is, for each square foot
of grate surface there is 35 square feet of heating surface to warm the
passing air. Should this ratio be increased to 50 to 1 the efficiency
of the furnace would be much improved.
If the ratio of heating surface to the grate surface is too small for
its requirements, the temperature of the air-heating surfaces must be
very high to provide the desired amount of heat. Under such a condition
the efficiency of the furnace would be low, since in all cases where
rapid combustion is required the available amount of heat per pound of
coal consumed is low. With a large amount of heating surface, the air
remains in contact with the hot surface a relatively longer period and
the desired temperature is reached with the expenditure of a smaller
amount of fuel. A momentary exposure of the air to a red-hot surface
is far less effective than a prolonged contact with a surface having
only a moderate temperature. Time is an element of great importance
in heating air. In considering the relative merits of two furnaces
with the same amount of grate surface, that with the larger amount of
heating surface will evidently be the most efficient.
The supply of heat comes primarily from the burning coal on the furnace
grate. The grate surface should be large enough in area to permit the
required quantity of heat to be generated by the burning fuel with
a moderate fire. If the grate surface is too small for the required
purpose, a hot fire will be necessary, when the normal amount of heat
is demanded by the house. During extremely cold weather, particularly
when accompanied by high wind, the extra heat demanded to keep the
house at the desired temperature makes necessary the use of an amount
of fuel that cannot be burned on the grate unless the fire is forced.
Hot fires can be kept up only at the expense of a large amount of heat,
and the resultant efficiency of the furnace is reduced.
High furnace temperatures are always attended by a large loss of heat.
The vastly greater quantity of air necessary to create the combustion,
the high temperature of the chimney gases and the increased velocity of
the heated gases through the furnace, all tend to increase the amount
of heat that is sent up the chimney, and to decrease the percentage
of heat that is delivered by the furnace. In order to heat the house
economically the furnace must be large enough to easily generate the
required amount of heat demanded in the most severe weather.
=Furnace-gas Leaks.=--The presence of furnace gas in the atmosphere of
a house is not only annoying but may be a source of danger. Gas leaks
are commonly due to the imperfect union of the various parts of which
the furnace is composed.
Cast-iron furnaces are constructed in sections that are assembled to
form a complete plant. In assembling, the various parts of contact must
be carefully joined to prevent the gases in the fire-box from escaping
into the air-heating space. In the manufacture of cast-iron furnaces it
is practically impossible to form gas-tight joints by the contact of
the metal alone. In the erection of the furnace all doubtful joints are
filled with stove putty. Furnaces of good design require the use of the
least amount of this material.
Stove putty is composed of finely divided graphitic carbon that is
made into a paste suitable for filling all imperfect joints. When
the putty hardens it withstands the heat to which it is subjected,
without shrinking. In the course of time, however, the putty may be
displaced and leave openings through which the furnace gases may leak
into heating space and thus enter the house. Leaks of the kind may be
stopped by renewing the putty which may be obtained from any dealer in
stoves.
=Location of the Furnace.=--The location of the furnace will generally
be governed by the exposure of the house and the location of the
chimney. In all exposed rooms on the windward side of the house the
temperature will be lower and the air pressure higher than in other
parts of the house. The increase in atmospheric pressure makes it
necessary to supply to such rooms the hottest air practicable. The
conducting pipes, therefore, should be most directly connected with the
furnace and with the least run of horizontal pipe. The proper place for
the furnace is as near as possible the coldest place of the house.
It is a common practice to place registers near the inner corner of
the room, in order to economize in conducting pipe, in horizontal
runs. A small amount of economy in first cost is thus secured but the
efficiency of the apparatus is sacrificed.
The greatest objection to placing the registers and conducting pipes in
the outer walls of buildings is that of loss of heat, due to exposure
to the outside cold and the resulting loss in circulation. Losses of
this kind may be prevented by covering the ducts with the necessary
non-conducting material. The registers should occupy a place in the
room nearest the entering cold air.
[Illustration: FIG. 46.--Method of conducting warm air from the furnace
to the registers.]
=Flues.=--It is customary to place the conducting pipes for the first
floor in such a way as to use only the shortest connections. The flues
used for the second floor produce, as in a chimney, a greater velocity
of flow to the air and as a consequence larger _horizontal_ pipes are
used at the furnace. All horizontal pipes should have upward slant, as
much as the basement will permit.
The velocity of the air in the conducting flues will depend on two
factors: the height of the flue, and the temperature of the air. To
prevent the loss of the temperature of the air, the flue should be
covered with at least two layers of asbestus paper bound with wire.
Wall flues are commonly flattened and occupy a place in the wall
between the studding. Each flue should have a damper at the furnace,
that will permit the heat to be shut off from any part of the house.
Rules for proportioning of registers and conducting flues to suit
rooms of various sizes are entirely empirical. The sizes of registers
and flues found satisfactory in practice is generally a guide for the
designer. The following table is taken from a manufacturer’s catalogue
and gives a list of sizes that have proven satisfactory under a great
variety of conditions and may be taken as good practice:
FIRST FLOOR
-----------+-------------+------------+-----------
Sizes of | Diameter of | Size of | Height of
registers | pipes | rooms | ceilings
in inches | in inches | in feet | in feet
-----------+-------------+------------+-----------
12 by 15 | 12 | 18 by 20 | 11
10 by 14 | 10 | 15 by 15 | 10
9 by 12 | 9 | 14 by 15 | 9
8 by 12 | 9 | 13 by 13 | 9
-----------+-------------+------------+-----------
SECOND FLOOR
-----------+-------------+------------+-----------
10 by 14 | 10 | 18 by 20 | 10
9 by 12 | 9 | 16 by 16 | 9
8 by 12 | 8 | 13 by 13 | 8
8 by 10 | 7 | 12 by 12 | 8
-----------+-------------+------------+-----------
The furnace is not only a means of heating the house but may be a means
of ventilation as well; to this end it is desirable to arrange the air
supply of the furnace to connect with the outside air. This arrangement
assures a supply of oxygen even though no special means is arranged for
discharging the vitiated air from the rooms.
[Illustration: FIG. 47.--Interior construction of a combination
hot-water and hot-air furnace.]
=Combination Hot-air and Hot-water Heater.=--In the case of large
houses heated by hot air it is sometimes better to use two or more
furnaces than to attempt to carry the heat long distances in the
customary pipes. Where heat is required in rooms located at a distance
more than 30 feet, it is advisable to use a combination hot-air and
hot-water heater, the distant rooms being heated by hot-water radiators.
A furnace arranged for such a combination is shown in Fig. 47. This
furnace contains, first, the essential features of a hot-air furnace;
next, it includes a hot-water plant. The fire-box and air-heating
surfaces are easily recognized. The arrows show the course of the air
entering at the bottom of the furnace, which after being heated by
passing over the heating surfaces, escapes at the openings marked _warm
air_, to the distributing pipes.
[Illustration: FIG. 48.--The hot-air furnace as it appears in the
house.]
Inside the air-heating surfaces are three hollow cast-iron pieces _W_,
that form a part of the walls of the fire-box. These pieces, with their
connecting pipes, form the water-heating part of the furnace, which
supplies the hot water for the radiators. The pieces _W_, with the
connecting pipes and radiators, form an independent heating plant, with
a fire-box in common with the hot-air furnace.
The returning water from the radiators enters the heating surfaces _W_,
through the pipe marked _return pipe_. The heated water is discharged
from the heaters into that marked _flow pipe_ which conducts it to the
radiators. Such a furnace is, therefore, two independent systems, one
for hot air and the other for hot water, but with a single fire-box.
This furnace, like the simple hot-air furnace, is rated, first in the
amount of space it will heat with hot air and in addition, by the
number of square feet of hot-water radiating surface that will be kept
hot by the hot-water heater.
In Fig. 48 is shown the location of the furnace in a cottage with the
conducting pipes to the various rooms. The registers in the first floor
are generally set in the floor but if desired they may be placed in the
walls. Those on the second floor are placed in the walls because of
convenience. The conducting pipes pass through the partitions between
the studding.
[Illustration: FIG. 49.--Details of air ducts and damper regulator used
with the hot-air furnace.]
In all well-arranged hot-air heating plants provision is made so that
the air for heating may be taken from the outside. It does not follow
that the supply of fresh air should always come from outdoors; there
are times during extremely cold weather, accompanied by high winds,
when ventilation is ample without the outside source of supply. Since
it is never desirable to take the air supply from the basement, such
an arrangement as is shown in Fig. 49, or a modification of the same
plan is commonly employed. The duct _A_ from the outside and _B_ from
the rooms above connect with the air supply for the furnaces. A damper
_C_ arranged to move on a hinge, is so placed as to admit the air from
either source as desired. The damper may be placed so as to take part
or all of the air from the outside by adjusting the handle at the
proper place.
CHAPTER IV
TEMPERATURE REGULATION
The method used for regulating the temperature of a house will depend
on its size, the conditions under which it is to be used and the method
of heating. In small houses the temperature may be satisfactorily
governed entirely by hand, that is, the furnace drafts may be changed
by hand to suit the varying conditions of temperature. A more
satisfactory method is that of thermostatic regulation, in which a
thermostatic governor and a motor automatically control the furnace
dampers so as to keep a constant temperature at one point, generally
the living room. Where hot-water or steam heating plants are used,
another device is frequently employed to keep the temperature of the
heat supply at a constant degree. This is known as the automatic damper
regulator. The damper regulator is one of the boiler accessories which
so governs the drafts of the furnace as to keep a constant water
temperature in the hot-water heater or a constant steam pressure in the
steam boiler.
In some cases both the damper regulator and the thermostat are used as
a more complete means of temperature control.
=Hand Regulation.=--As a means of changing the dampers of the
furnace from the floor above, to suit the prevailing conditions, the
arrangement shown in Fig. 49 does away with the necessity of a journey
to the basement, to remedy each change of temperature.
A plate is fastened to the wall at any convenient place, to which the
end of a chain is attached as shown in the figure. This connects with a
second chain, the ends of which are fastened, one to the direct draft
or ash-pit damper _F_, and the other to the check draft _E_, in the
chimney. As the furnace appears in the drawing, the direct draft is
closed and the check draft is open. By changing the ring from _G_ to
_H_, the movement of the chain opens _F_, and closes _E_, admitting
air to the furnace. When the temperature of the room is raised
sufficiently, the drafts are restored to their original position by
replacing the ring at _G_. Sometimes one or more intermediate points
are made on the plate between _G_ and _H_, which permits both drafts
to be kept partly open and fewer changes are required to keep the
temperature approximately normal.
[Illustration: FIG. 50.--Cross-section of damper regulator for steam
boiler.]
[Illustration: FIG. 51.--Steam boiler for house heating, with the
damper regulator, in place, attached to the dampers.]
=Damper Regulator for Steam Boiler.=--The damper regulator used on
a steam boiler is a simple device that automatically controls the
draft dampers by reason of the changing pressures of the steam. The
object of the damper regulator is to prevent the generation of steam
in the boiler beyond a certain pressure at which the valve is set.
This point is usually 3 or 4 pounds below the pressure at which the
safety valve would act. If in proper working order the damper regulator
will so control the dampers that the boiler will always contain a
supply of steam, but the pressure will not reach a point requiring
the action of the safety valve. Fig. 51 illustrates its connections
with the furnace dampers. In Fig. 18 the regulator appears at _D_. In
external appearance and in operation of the dampers, it is the same
as the regulator for a hot-water boiler but its internal construction
is simpler. Fig. 50 shows its construction. It is attached to the
steam space of the boiler at _E_. The steam pressure acts directly on
the flexible metallic diaphragm _B_. As the pressure of the steam
approaches the desired amount the diaphragm is raised and with it the
lever _V_. A chain _D_, attached to the end of the lever, opens the
check draft, and another at _C_ closes the draft damper. When the steam
pressure falls, the diaphragm lowers the lever and the dampers are
restored to their original position. The same movements are repeated
with each rise and fall of the steam pressure.
[Illustration: FIG. 52.--Damper regulator for hot-water boiler.]
=Damper Regulators for Hot-water Furnaces.=--The damper regulator for
a hot-water boiler automatically controls the dampers of the furnace
so as to keep the water of the boiler approximately at a constant
temperature. The regulator is shown in Fig. 52. The ends of the lever
are connected to the direct-draft and check-draft dampers, as in the
case of the damper regulator for the steam plant. A cross-section of
the working parts shows the details of construction. The lever _d_
is operated by a diaphragm _g_, which tightly covers a brass bowl,
containing a mixture of alcohol and water, of such proportions as will
produce a vapor pressure at the desired temperature, say 200°. The
hot water from the boiler passes through the valve, entering at _a_
and leaving at _b_. When the water reaches the desired temperature,
the contained liquid vaporizes and a pressure is produced that is
sufficient to lift the diaphragm and the lever. The chain attached to
the right-hand end closes the direct-draft damper; at the same time the
other end of the lever opens the check draft, and the supply of air to
the furnace fire is entirely cut off. As soon as the water has cooled
sufficiently, the vapor pressure in the bowl is reduced, allowing
the weight _W_ to depress the diaphragm and the lever is restored to
its first position. The weight _W_ is for adjusting the valve to the
desired temperature. The plug _f_ tightly closes the orifice through
which the liquid is introduced into the bowl.
The object of the damper regulator on a hot-water boiler is to govern
the fire of the furnace so as to keep the water in the boiler at the
desired temperature. In case there is a demand for heat at any part of
the house, a supply of hot water will always be on hand. It has nothing
to do with the regulation of the temperature of the house. The control
of the house temperature is the office of the _thermostat_.
=The thermostat= is a mechanical device for automatically regulating
temperature. It may be arranged to operate the valve of a single
radiator or register and so control the temperature of a room, or as
commonly used in the average dwelling, the controller may be placed
to govern the temperature of the living room and in so doing keep the
furnace in condition to satisfactorily heat the remainder of the house.
Thermostats are made in a variety of forms by different manufacturers
but they may be divided into two general classes: the electric, and
the pneumatic types. The electric thermostat depends on an electric
current as a means of controlling the action of the motor which in turn
operates the furnace dampers so as to maintain a constant heat supply.
The pneumatic thermostat regulates the supply of heat by means of
pneumatic valves. It will be considered later in discussing mechanical
ventilation. This type of temperature regulation is particularly
adapted to large buildings.
Fig. 53 illustrates one style of electric thermostat that is very
generally used for temperature regulation in the average dwelling. It
consists of three distinct parts--the controller, the electric battery
and the motor. In the drawing the motor is shown connected with a
steam valve, such as may be used for furnishing steam for a series of
radiators. It may with equal facility be attached to the dampers of a
furnace or other heating apparatus.
The controller occupies a place on the wall of the room to be heated
and makes electric connections between the battery and the motor.
Whenever the temperature varies from the required degree, a change of
electric contact in the controller starts the motor, and the radiator
valve or the furnace drafts are opened or closed as occasion requires.
The controller appears in Fig. 54 as commonly seen in use. The
upper part carries a thermometer and the pointer _A_ indicates the
temperature to be maintained in the room. The middle division indicates
70°F. Each division to the right of the middle point raises the
temperature 5°. Each division to the left lowers the temperature a like
amount.
In addition to the ordinary type this controller is furnished with
a time attachment by means of which the controller may permit the
temperature of the room to fall to any desired degree at night and
raise it again in the morning at the time for which it is set.
This is accomplished by a little alarm clock shown at the bottom of the
controller in Fig. 54. The indicator _B_ is arranged to correspond with
the indicator _A_; the middle point representing 70°F. To set the time
attachment, the alarm is wound and set as in any alarm clock, 1/2 hour
earlier than the desired time for rising. The indicator _B_ is set for
the day temperature and _A_ is set for the temperature desired during
the night. At the appointed time the alarm moves the indicator _A_ to
the desired point for the day and the controller raises the temperature
accordingly.
Fig. 55 shows the mechanism that is exposed to view when the cover
of the controller is removed. The bent strip _C_ is the part that is
influenced by the change of temperature. It is made of two thin strips
of metal, one of brass and the other of steel. The two strips are
soldered firmly together. Any change in temperature will affect the
strip and cause it to bend and touch the contact point--_K_ or _J_. The
bending of the strip is due to the unequal expansion of the brass and
steel due to the change of temperature. Brass expands 2.4 times as much
as steel with the same change of temperature. The amount of bending
is sufficient to make an appreciable movement in a small fraction of
a degree change. The brass part of _C_ is on the left and since it
expands the greater amount, a rising temperature causes _C_ to come
into contact with the point _J_. When this happens the motor is started
and makes one-half cycle. In so doing it shuts off the air supply
of the furnace, opens the check draft and at the same time the motor
changes the electric contact from _J_ to _K_. When the temperature
begins to fall, the brass contracts in the same ratio to the steel as
it expands during the rising temperature and as a consequence the bar
bends to the left. When the strip touches the point _K_ the motor again
makes one-half circle, admitting air once more to the furnace, closes
the check draft and shifts the electric contact back to _K_. When
properly started the thermostat will regulate the temperature within a
degree of temperature.
=The Thermostat Motor.=--The thermostat motor automatically opens
and closes the furnace dampers or the valve that admits steam to the
radiators as heat is demanded by the controller.
The motor, as shown in Fig. 53, consists of a system of gears and a
brake _S_, which regulates the speed, a cam _M_, and armature _I_, for
starting and stopping the motor, and the electromagnet _H-H_ which
operates the bar _I_. Two lever arms _L_, one in front and the other
at the back of the motor furnish means for attachment to the valve or
furnace dampers. An emergency switch at _D_ is shown in detail in Fig.
56. The battery _B_ furnishes the current which energizes the magnets
and an iron weight supplies the motive power for the motor.
The description of the operation of the motor applies to the steam
valve shown in Fig. 53. The same motor might be used for opening and
closing of the dampers of the furnace in any kind of heat supply. The
method of communicating the motion of the motor arms to the dampers of
the furnace will be described later. The connections with the furnace
drafts are shown in Figs. 3, 6, 8, 34, etc.
Suppose that the valve for admitting steam to the radiators, as
that in Fig. 53, is closed and that the temperature of the house is
falling. The strip _C_ of the thermostat controller is moving toward
_J_. When contact is made, the current from the battery _B_ energizes
the magnets _H-H_ and the bar _I_ is lifted. As the bar _I_ is raised
the catch _J_ is released and permits the motor to start. The bar _I_
is held suspended by the cam _M_ until the arm _L_ has made one-half
revolution, when the lug _K_ drops into the depression in the cam made
to receive it and the catch _J_ engages with the brake and stops the
motor.
[Illustration: FIG. 53.--Thermostat complete with the regulator,
battery and motor, attached to a steam supply valve.]
During this movement the arm _L_ has lifted the valve arm _N_ and the
valve admits steam to the radiators, at the same time the contact _M_
has been shifted from the right-hand contact to the left, and the
electric circuit is ready to be made in the controller at the point
_K_. When the temperature has fallen a sufficient amount the controller
bar _C_ will make contact at _K_ and the motor will again make a half
cycle, changing the valve back to its original position. This process
will be kept up so long as the motor is wound and there is sufficient
fuel in the furnace to raise the temperature.
Fig. 55 shows the method of connecting the electric wires from the
battery to the controller. A three-wire cable connects the battery, and
makes contacts as indicated at _H_, _K_ and _J_. The wires are shown
attached to the motor as in Fig. 55. A wire is taken from either pole
of the battery and attached to one of the ends of the magnet coil.
Passing through the magnet the wire is attached to the frame of the
motor. This makes the cam _M_ a part of the electric circuit. The other
two wires are attached to the brass strips on each side of the arm _L_.
The strips are insulated from the frame. The electric circuit through
the magnet is made alternately by contact with the strips at right and
left of the arm _L_.
[Illustration: FIG. 54.--Thermostatic regulator with clock attachment
for control of day and night temperature.]
In case the motor, through neglect, runs down, a safety switch at _D_
(Fig. 53) disconnects the battery and keeps it from being discharged.
This switch is shown in detail in Fig. 56. When the weight has reached
its limit, the piece _C_ on the chain comes into contact with _D_ and
lifting it out of contact, breaks the circuit. When the motor is again
wound, _C_ engages with _E_ and restores the contact. The switch is so
arranged that when open, the valve will always be closed.
[Illustration: FIG. 54_A_.--Showing the clock attachments to the
thermostatic regulator.]
[Illustration: FIG. 55.--Mechanism of the thermostatic regulator.]
=Combined Thermostat and Damper Regulator.=--It is evident that, in
heating a house by steam, the _damper regulator_ governs only the
steam pressure of the boiler. In the use of a thermostat alone, the
regulation is that of the temperature of the rooms only, and has
nothing to do with the steam pressure. As an example: Suppose that in
cold weather the house is cold and that the gage of the steam boiler
shows no pressure. The desire is to get up steam as soon as possible.
In so doing a hot fire is made with a large amount of fuel. As soon
as the steam begins to form, the pressure rises rapidly. When the
radiators have become hot and the steam is no longer taken away as
fast as it is formed, the pressure of the steam in the boiler keeps on
rising. The thermostat will not close the furnace dampers until the
temperature of the rooms is normal. This may require so great a length
of time as to produce a great excess of steam that cannot be used at
the time and the pressure will be relieved by the safety valve. This
may not be dangerous but it is disagreeable. To prevent the safety
valve from blowing except in case of emergency, a combined thermostat
and draft regulator is used. In such a combination, the draft
regulator closes the draft as soon as the pressure reaches the desired
point, after which the thermostat does the regulating according to suit
the temperature of the house.
In Fig. 2 is shown such a combination attached to a boiler. The cord
from the regulator, instead of extending directly to the direct-draft
damper, passes over the pulley _P_ and connects to the thermostat cord.
The regulator may now close the damper to suit the steam pressure,
but after the temperature in the rooms is normal, the amount of heat
necessary to maintain the desired degree is regulated entirely by
the thermostat which opens and closes the dampers regardless of the
position of the damper regulator.
If occasion should require but a very slight amount of steam to keep
the house at the desired temperature, the thermostat will govern
the drafts aright. If the steam pressure is in danger of becoming
excessive, the damper regulator will govern the drafts.
[Illustration: FIG. 56.--Automatic switch which opens the battery
circuit when the thermostat motor weight, reaches its limit.]
=Thermostat-motor Connections.=--The arrangement of cords and pulleys
used for attaching the thermostat motor to the furnace dampers will
depend very much on local conditions. The motor can be placed in
any convenient position so that the connecting cords will act most
directly. The motor opens and closes the direct draft and check draft
in accordance with the demand for heat. The connections for all kinds
of furnaces are made in much the same manner. The pulleys supplied
with the motor are placed to work as freely, and the cords to pull as
directly as possible.
In Fig. 57 the motor is connected with a hot-air furnace. The cord
_D_ is attached to the front arm of the motor and connects with the
direct-draft damper _F_. The cord _C_ connects the rear arm of the
motor with the check-draft damper at _E_. In the position of the
dampers shown, the direct-draft damper is closed and the air is
entering the chimney through the check draft _E_. While this damper is
open there is very little induced draft to supply the fire with air
that might leak through the crevices around the ash-pit door, but the
gases from the furnace are completely carried away to the chimney by
the air entering at _E_.
[Illustration: FIG. 57.--Thermostat motor connected with the dampers of
a hot-air furnace.]
In Figs. 3, 6, 8, 34, etc., the same motor is connected with the
furnaces of various other systems of heating. The object is the same
in all; when less heat is required, the air supply is cut off and the
furnace fire subsides; when more heat is demanded the air is again
admitted to produce greater combustion. The check draft is an important
feature as it checks the flow of air through the furnace regardless
of the position of the direct-draft damper. Even should the direct
draft be left open, the check draft when open would destroy in a great
measure the supply of air entering the furnace.
CHAPTER V
MANAGEMENT OF HEATING PLANTS
The following instructions on the care and management of steam and
hot-water heating plants is printed with permission of the American
Radiator Co. They were prepared as a guide to the successful operation
of the Ideal heating plants but apply with equal force to other plants
of a similar character.
=General Advice.=--No set rules can be given for caring for every
boiler alike--chimney flues are not alike--some have strong draft,
some are average and some are weak. There is much more difference in
the heat-making qualities of coal than is commonly known, and it is
important that the right size coal for the draft be used. These rules
apply to most all fuels. A little trying of this way or that way of
leaving the dampers (when regulators are not used) often discovers the
better way. It is well to vary from the rules a little if any of them
do not seem to bring about the best results.
With good, average chimney flue draft and the right kind of fuel, these
rules will govern the large majority of cases.
=The Economy of Good Draft.=--In many cases a boiler with sluggish
draft will burn more coal than a boiler with good draft. In the first
case the fuel may be said to “rot”--in lacking air supply the gases
pass off unburned. The “nagging” which a boiler has to take under these
conditions increases the waste of fuel. A boiler under sharp, strong
draft maintains a clear intense fire and burns the gases--getting the
larger amount of heat from the coal.
=General Firing Rules.=--
1. Put but little coal on a low fire.
2. When adding coal to the boiler, open the smoke-pipe damper (inside
the smoke pipe) and close the cold-air check damper. This will make a
draft through the feed doorway inward and prevent the escape of dust or
gas into the cellar when the feed door is open to take fuel. Put these
parts back to their regular places after feeding.
3. When it can be done, in feeding a large amount of coal (as for
night) leave a part of the fire or flame exposed, so that the gases may
be burned as they arise.
4. When a regulator is not used, learn to use the dampers correctly
and according to the force of the chimney draft. Learn to use cold-air
check damper. Often, when closing, the ash-pit draft damper does not
check the fire enough; opening the cold-air check damper will check it
about right. Increasing or lessening the pressure of a steam boiler
must be done by changing the weight on the regulator bar.
5. Carry a deep fire or a high fire; let the live coals come up to the
feed door--even in mild weather when from 4 to 6 inches of ashes stand
on the grate.
[Illustration: FIG. 57_a_.--Indicates the general condition of the
furnace fire during very cold weather. The fuel should fill the
fire-pot to _C_. The ashes should not be allowed to accumulate beyond
_B_, on the grate. There should be no more ashes than appear at _H_, in
the ashpit.]
6. In severe weather give the heater the most careful attention the
last thing at night.
7. Do not overshake or poke the fire in mild weather; once in a while
shake enough to give place for a little more fuel.
8. Do not let ashes bank up under the grate in ash-pit. Grate bars are
very hardy, but it is possible to warp them with carelessness. Taking
up the ashes once a day is the best rule, even if but little has fallen
into the pit.
9. Keep the boiler surfaces and flues clean; a crust of soot 1/4 inch
in thickness causes the boiler to require half as much more fuel than
when the surfaces are clean.
10. If convenient, have a water hose to spray the ashes when cleaning
out the pit.
11. Attend the boiler from two to four times per day. In mild weather,
running with a checked fire, morning and night is usually often enough.
In severe weather, once in early morning, again at mid-day, again at
five or six o’clock and finally thorough attention at from nine to
eleven o’clock in the evening.
12. If, through burning poor coal, the fire pot gets full of ashes,
or slate and clinkers massed together, the quickest way to get a good
active fire is to dump the grate and then build a new fire--from the
kindling up.
13. If a _hard clinker_ lodges between the grate bars, do not force the
shaking, but first dislodge the mass with a poker or slicing bar. Then
the grate will operate without damage.
=Weather and Time of Day.=--In _severe weather_ keep the fire pot full
of coal, and run the heater by the dampers or regulator (if one is
used). Thoroughly clean the grate twice a day. Let the top of the fire
in front be level with the feed door sill. Bank up the coal higher to
the rear.
In _moderate weather_ there should be from 2 to 6 inches of ashes
between the live coal and the grate. As the weather grows colder keep
the grate and the fire pot a little cleaner--sometimes it helps to run
the poker or slicing bar over it through the clinker door. With some
fuels this is never necessary.
=Night Firing.=--In very _cold weather_, when the house should be kept
warm all night, clean the grate well at a late hour--the last thing.
Clear the bottom of the fire pot of all ashes and clinkers so that the
grate is covered with clear-burning, red-hot coals, then fill the pot
full of fuel. If possible, leave some of the flame exposed to burn the
gases. Leave the drafts on long enough to burn off some of the gas,
then check the heater for the night. Thus there is plenty of coal
to burn during the night and some on which to commence early in the
morning. Some drafts do not make it necessary to leave the dampers on
to burn off the gas after feeding.
With the ash-pit draft damper closed and the cold-air check damper
open at night, but part of the coal is burned and there is much of it
not burned in the morning. So, by reversing the dampers in the early
morning the fire starts up quickly and often the house may be well
warmed before any coal is put into the fire pot.
Some boilers are run the other way--a very poor way. If the grate is
cleared off in very cold weather and coal added at five or six o’clock
in the afternoon, by eleven o’clock at night nearly one-half of the
coal is burned and the grate is covered over with a mass of ashes and
clinkers. With little coal remaining, to shake the grate will quite
likely put out the remaining fire; to put fresh coal on a low fire
reduces further its declining temperature. The result is a cold house
that will grow colder until a new fire is started.
Often in cold weather with this poor way of night firing, it takes one
or more hours of forced firing to warm the house in the morning, and
all the coal saved the night before is more than used to get the house
or building “heated up”--while the people who should be comfortable
have to get up, bathe and take breakfast in chilly rooms. At no time
in the day is heat more wanted than about the time of getting up and
starting the day. A fire well cared for late in the evening makes a
warm house all night. And so it follows that it is much easier to add
a little more heat in the morning. And surely less coal is burned, for
the forcing of a fire part of the time often overheats, and wastes coal.
=First-day Firing.=--In the morning of _moderate winter weather_,
with the ash-pit draft damper open, before adding any coal allow the
fire to brighten up if it seems to be low; then (for such conditions)
spread over a thin layer of fresh coal and set the drafts for a brisk
fire. After the new fire is well started add as much coal as may be
necessary to last until next firing. Do not shake much if any--just
enough to give space for more coal. Then by setting the regulator (if
one is used), or, by closing the ash-pit draft damper and opening the
cold-air check damper a little, the boiler should keep up its work
until the next firing time.
In _severe weather_, if the boiler has been attended to at night as
directed in the section on “night firing,” the drafts can be turned on
and the boiler run for half an hour before adding coal. Or, if more
convenient to give it immediate attention, the grate can be thoroughly
shaken and enough coal added to last until mid-day. Often the cold-air
check damper will need to be entirely closed and the ash-pit draft
damper partly open if the heater is a water boiler. If a steam boiler,
the regulator should then be set to maintain the number of pounds of
pressure wanted and so left.
=Other-day Firing.=--In _severe weather_ more coal should be added
about noon, sometimes the draft may be left on for a few minutes and
then checked. And in such weather it is often well to give the boiler
further attention at five or six o’clock. In severest weather the
boiler should not be attended more than four times a day; and generally
not less than three times.
Often much coal is wasted by “nagging” the fire--poking, shaking and
feeding it until it becomes “dyspeptic.” A sure cure is a little common
sense in regular feeding, etc.
=Economy and Fuels.=--In running many boilers for _moderate weather_
better results follow if the grate is not shaken too much or too often.
Sometimes in _moderate_ weather a body of ashes on the grate checks the
fire and there is enough heat without a useless burning of fuel. Many
houses are overheated in _moderate_ weather and too much coal burned by
running the boiler as for zero weather.
So we repeat--_it is not wise to overshake or overfeed a boiler in
moderate weather_. The fire should be in such shape that if a change
comes at night there is a basis for a good fire to start on. When
the grate is shaken but once during the 24 hours (during _moderate_
weather) late at night is the best time.
When one stops to think that heating is needed during about 7 months
out of the year, and that _a greater portion of this time is usually
moderate weather_ when a very little heat is needed, it must be seen
that the science of running the heater to save coal is to apply common
sense rules of limiting the feeding and the attention in such periods.
In _severe weather_ we believe in giving the boiler a liberal quantity
of fuel regularly and at the right time. The time to save coal is when
there is no need for burning it. This is where a great many people make
errors in running the boiler--in forgetting to “let up” on the shaking
and feeding in moderate weather.
With some drafts and for boilers using hard coal or coke, good
economical results often are secured by opening the feed door a little
when it is desired to check the fire in moderate weather. This depends
on the draft.
=For Burning Soft Coal.=--Some types of boilers are made to burn
soft coal with economy, with least work. Some types are made
specially to burn the meaner grades of soft coal. Firing to prevent
smoke is a source of economy and these ways of running should be
followed--specially with large sectional boilers.
There are two types of soft coal, viz.: The free-burning coal, which
breaks apart when burning, allowing the gases to freely escape; and
the fusing-coking coal, which, when burning, first fuses into a solid
burning mass with a hard crust over the top, slowly coking as it burns.
The latter kind is most valuable for house-heating boilers because the
gases are more thoroughly consumed. The fusing-coking coal is worth
about 20 per cent. more for this purpose than the free-burning coal.
The gases should be allowed to pass off from the coal _slowly_. Leave
air inlet on the feed door open if draft permits. If possible, use
uniform sizes of coal. Avoid using coal having too much dust--the
“run-of-the-mine” may be lower in price but its heat-making value is
also low.
For the purpose of slow burning of soft coal, it is well in feeding at
night to let the fire burn up freely so that the coals are very live
with heat. Then fill in enough coal to last all night--leaving some of
the live coals uncovered if possible. With large sectional boilers this
exposure should be at the rear of the fire so that the flame will pass
over the live coals. Thus the gases coming off from the fresh coal are
burned and a larger amount of the full heat-producing value of soft
coal is made use of and with less smoke.
After a boiler is so fed, the dampers (unless an automatic regulator is
used) should be left about as follows:
Ash-pit draft damper open a little or closed, as draft may require.
Cold-air check damper open about one-eighth to one-third distance of
the opening.
Smoke-pipe damper about one-half closed.
A little experiment with the draft will usually tell the operator the
best way of leaving these dampers.
It will be found in the morning that the entire charge of coal is well
burned or partly coked.
The coked fuel, or that which sticks together in a mass, should be
broken up by the poker and more added generally as by rules given in
other sections.
It must always be remembered that the soft coals mined in different
parts of the country have widely varying heat-making capacities. To
obtain satisfactory results brands must be selected which have an
established reputation for excelling results in small boilers.
=For Burning Coke.=--It is best to keep the pot _full_ of fuel--keeping
a large body of coke under a low fire rather than a little fuel under a
strong fire.
It must be remembered that coke makes a very “hot fire” because the
coke is free-burning. Care should be taken not to leave drafts on too
long in boilers not having regulators.
Coke burns best for house-heating purposes with less draft than is
required for coal, therefore to keep a low fire the ash-pit draft
damper should be kept closed, and the smoke-pipe damper almost entirely
closed. The regulator (when used) can be set to keep the dampers about
as here advised. Coke is practically smokeless and its quick-burning
character makes a cut-off damper in the smoke pipe (which will stay
fixed as it may be set) quite necessary.
It is well to keep a layer of ashes on the grates and when shaking stop
before red-hot coals come through the grate. The coke then burns more
slowly, which increases its effectiveness.
With some drafts it may be well to “bank the fire” at night with
coke--pea coal size. This is a matter of experiment, and depends on the
character of the chimney draft.
Fire should be tended regularly--two times a day, or four at the
outside.
With an extra strong draft, at night the fuel should be packed down by
tamping with the back of a shovel.
With ordinary condition of draft, crushed coke, small egg size, should
be used.
=Other Rules for Water Boilers=--_To Fill System._--Open the feed-cock
when the heater is connected with a city or town water supply; if not,
fill by funnel at the expansion tank. Fill until the gage-glass on the
expansion tank shows about half full of water. In filling the system
see that all air cocks on the radiators are closed. Then beginning with
the lower floor, open the air cocks on each radiator, one at a time,
until each radiator is filled; then close the air cock and take the
next radiators on upper floors until all are filled, after which let
the water run until it shows in the gage-glass of the water tank. After
the water is heated and in circulation, vent the radiators by opening
the air valves as before. Then again allow the water to run into
the system until it rises to the proper level in the expansion tank
gage-glass.
Always keep the apparatus _full of water_ unless the building be
vacated during the winter months, when the water should be drawn off to
prevent freezing. _Never draw water off with fire in the heater._
To draw off water, open the draw-off cock at the lowest point in the
system, and then open air cocks on all radiators as fast as the water
lowers beginning with the highest radiator.
=Air-vent Valves on Radiators.=--In order to secure the full benefit of
the heating surface of a hot-water radiator, the inside of the section
must be free of air. When a radiator is “air-bound” it means that parts
of the sections are filled with air in pockets which remain until the
air is allowed to pass off through the vent valve.
Air will gather from time to time at the highest points inside the
radiators, especially in those placed in the upper stories of the
building. These air accumulations inside cut down the working power of
a radiator exactly in proportion as they rob the inside of the casting
of proper contact with heated water. Air pockets not only reduce
effective heating surface, but they also prevent the circulation of hot
water.
Therefore, it is well once in a while to take the little key provided
by the heating contractor and open the air valves on radiators to allow
the air (if any) to escape. When a radiator does not work as well as
usual, open the air valves until the water flows, which indicates that
the air has been fully released. Then close the valve.
=Valves on Cellar Mains.=--If cut-off valves have been placed on the
main and return pipes in the cellar, see that the valves on one line
of main and return pipes (at least) are open when the boiler is under
operation. Be sure that the system is open to circulate water through
the supply and return pipes before building a fire in the boiler.
=End of the Season.=--At the close of the heating season clean all
the fire and flue surfaces of the boiler. Let the water remain in the
system during the summer months. No bad results will follow if the
system is not refilled more often than once in 2 or 3 years. But,
generally, it is thought that best results are secured by emptying the
system once a year (after fire is out) and refilling with fresh water.
It is a very good idea to take down the smoke pipe in the spring,
thoroughly clean and put it back in place. Leave all doors open on the
boiler in the summer time.
=Other Rules for Steam Boilers=--_To Fill Boiler._--Open the feed-cock
when the heater is connected with city or town water supply; if not,
fill through the funnel. Let the water run until the gage-glass shows
about half full of water.
In the first filling, after the water has boiled, get up a pressure
of at least 10 pounds, draw the fire and blow off the boiler under
pressure through draw-off cock to remove oil and sediment, after which
refill with fresh water to the water line. This is best done usually by
the steam-fitter.
The damper regulator will control the pressure of steam, closing the
damper when the pressure is raised beyond the desired point and opening
the damper when the pressure falls below that point. By removing the
weight on the lever, different degrees of pressure can be kept up. The
regulator should be allowed to control the drafts without interference.
Examine the water glass often to see that the _water line_ is at the
proper height. If lower than normal open the supply pipe until the
water runs in and stands at the proper level. It is best when no water
stands in the glass, nor shows at the bottom of the try-cock, to
quickly dump the grate and do not put water into the boiler again until
it is cooled off.
If there is one or more shut-off valves on the main or return pipes,
before starting a fire see that one line of piping at least (main and
return) is open to circulate the steam.
=To Control Radiators.=--When it is desired to shut off steam from any
radiator (if the regular radiator valves are used), close the valve
_tight_, and when it is turned on see that the valve is _wide open_.
A valve partly turned off will cause the radiator to fill with water.
This rule applies only to one-pipe heating systems.
=The Air Valves.=--If little keyed air valves (sometimes called
“pet-cocks”) are used, follow generally the same directions as outlined
for hot-water radiators on page 49--only, of course, in releasing the
air from the radiator open the valve with the key provided and close it
just as soon as the steam unmixed with air comes through the nose of
the valve.
If “automatic” air valves are used they must be carefully adjusted by
the steam-fitter and then left to operate without undue interference.
=End of the Season.=--At the close of the heating season fill the steam
boiler with water to the safety valve and let it thus stand through the
summer.
Also thoroughly clean all the fire and flue surfaces of the boiler and
at the opening of the next season withdraw the water and refill with
fresh water to the water line, starting the boiler as before.
It is advisable to have a competent steam-fitter blow off the boiler
under pressure and thus give the inside a thorough cleaning when the
boiler is first set up and ready for fire.
A low-pressure boiler, using good water, rarely needs blowing off after
it is once cleaned at time of setting up.
THE RIGHT CHIMNEY FLUE
The area of the flue should never be less than 8 inches in diameter
if round, or 8 by 8 inches if square--unless for a very small heating
boiler or tank heater. Nine or 10 inches round, or 8 by 12 rectangular
is a good average size. The flue should generally have a little more
area than that of the connecting smoke pipes.
Draft force depends very much on the height of the flue.
The chimney top should run above the highest part of the roof and
should be so located with reference to any higher buildings nearby that
the prevailing wind currents will not form eddies which will force the
air downward in the shaft. Often a shifting cowl which will always turn
the outlet away from the source of adverse currents will promote better
draft.
The flue should run as nearly straight up from the base to the top
outlet as possible. It should have no other openings into it but the
boiler smoke pipe. Sharp bends and offsets in the flue will often
reduce the area and choke the draft. The flue must be free of any
feature which prevents a free area for the passage of smoke. The outlet
must not be capped with any device which makes the area of the outlet
less than the area of the flue.
The best form of flue is a round tile--in such there is less friction
than in the square form and the spiral ascent of the draft moves in the
easiest and most natural manner.
If the flue is made of brick only, the stack should be at least two
4-inch courses in thickness.
If there is a soot pocket in the flue below the smoke-pipe opening, the
clean-out door should always be closed. If this soot pocket has other
openings in it--from fireplaces or other connections--such arrangements
are very liable to check the draft and prevent best action in the
boiler.
The smoke pipe should not extend into the flue beyond the inside
surface of the flue, otherwise the end of the pipe cuts down the area
of the flue and injures its drawing capacity.
The inside of a flue should be smooth (pointed or plastered). When
the courses are laid with the mortar bulging out from the joints the
friction within the flue is very much increased. Often a troublesome
flue is corrected by lowering some sharp-edged weight by a rope which
should be worked against the sides of the flue until the clogging is
scraped off.
A new chimney when “green” will not have a good drawing capacity. Short
use dries out the mortar and better results follow.
=“Smokey” Chimneys.=--The failure of draft in flues may be due to a
variety of causes, one of which is illustrated in Fig. 57_b_. The short
chimney on the left side of the roof shows the course of the wind
as it passes over the ridge of the roof and why the draft in such a
chimney is retarded whenever this condition exists. The force of the
wind, as it comes into contact with the roof, causes a compression of
the air on the windward side and a rarification on the lee side. This
inequality of pressure causes a downward sweep of the wind as indicated
by the arrows. The effect on the low chimney is to retard the draft and
sometimes the pressure is great enough to reverse the action of the
flue and force the smoke into the house. The only remedy for such a
condition is an extension of the chimney that will raise its top above
the ridge.
[Illustration: FIG. 57_b_.--Effect of the wind in causing down draft in
low chimneys.]
The same effect is often produced by a neighboring building or a border
of trees that are higher than the chimney and dense enough to effect
the wind pressure.
CHAPTER VI
PLUMBING
The term plumbing is usually understood to cover all piping and
fixtures that carry water into the house and remove the waste material
in the form of sewage. It does not include the pipes of the heating
system. Although the work of installing heating plants is frequently
done by plumbers, pipe fitting and plumbing are two distinct trades.
In the process of building a house the rough plumbing is put into place
as soon as the structure is enclosed and the rough floors are laid.
The rough plumbing includes the soil pipe, into which the waste pipes
from the various fixtures empty, and those pipes which must occupy a
position inside the partition walls and beneath the floors.
The connections here described are for a city dwelling and apply to the
custom of local conditions. The same system might be used for a country
residence except in regard to the water supply and method of sewage
disposal. Plants of this type are discussed in the chapter on _septic
tanks_.
Fig. 58 shows a cross-section of the street, exposing the sewer _S_,
the water main _W_, and the connections with the house. The side of the
house has been removed to permit a view of the water and sewer pipes,
connecting with the bathroom, kitchen, laundry and other basement
fixtures.
The lateral sewer or house drain, which connects the house with the
street sewer _S_, is provided with a trap _G_, located, in this case,
just outside the basement wall. The house drain is made of vitrified
tile, laid so as to grade into the street sewer with the greatest
possible pitch. The sections are laid as true as conditions will permit
and the joints are all carefully filled with cement mortar to prevent
leakage. The object of the trap _G_ is to prevent sewer gas from
entering the house from the main sewer. The trap prevents the gas from
passing because the water in the bend of the trap forms a water seal,
beyond which the polluted air from the sewer cannot travel.
[Illustration: FIG. 58.--Cross-section of a city street showing the
watermain and sewer pipe with their connections to a dwelling.]
Next inside the trap is the vent pipe _E_, that extends to the surface
of the ground. In this case it is just outside the basement wall.
The top is covered with a metal cap. Another arrangement often made
to accomplish the same purpose is shown in Figs. 61 and 62, where a
piece of soil pipe in the form of a bend is made to take the place of
the cap. Inside the basement and extending up through the partition
walls to the roof is the _waste stack_ or soil pipe _A_. This pipe as
is explained in detail later, is made of cast iron and is put together
with calked lead joints. The top of the stack at the point where it
passes through the roof is shown in Fig. 59. In extending through the
roof the pipe _A_ must make a water-tight joint to prevent water from
leaking through. This is accomplished by means of the metal plate _D_,
which is set under the shingles and the piece _C_, that is soldered to
_D_. The joint between _C_ and _A_ is best made with lead the same as
the other joints of the stack. In the case of very high stacks, the
bottom should be supported by a pier or iron pipe rest. Besides being
supported at the base the stack should be secured to the side walls or
floor beams at each floor. This is to keep the pipe from moving out of
place and the consequent opening of joints.
[Illustration: FIG. 59.--Detail of soil pipe connection.]
[Illustration: FIG. 60.--Cross-section of cellar-drain.]
All of the waste pipes from the bathroom, kitchen and basement drain
into the waste stack. The cellar drain for draining the basement is
shown at _T_ in Fig. 58. It also appears in detail in Fig. 60. The
plate _B_, in the latter figure, is set flush to the surface of a
depression in the floor that serves as a collecting point for water.
The floor is constructed to drain toward this point. The plate is
perforated to let the water through and is generally hinged so that
in case of stoppage the cover may be raised. The bell-shaped piece
under the cover surrounds the piece _C_, to form a water seal when the
level of the water is at _A_. In addition to this water seal there
is generally a trap between the drain and the sewer as shown in the
drawing.
The method of connecting the bathroom waste pipes with the stack is
shown in Fig. 99 and will be described later. All of the sewage of the
house is emptied into the stack by the most direct route, and from the
stack it is conducted as directly as possible into the sewer. From the
drawing it will be seen that all openings to the sewer are sealed in
two separate places, once at the outlet to prevent the air from the
street sewer entering the house drain _G_, and again at each opening to
prevent escape of the sewer gas from the drain into the house.
[Illustration: FIG. 61. FIG. 62.
FIG. 61.--House drain with outside vent, and running trap placed inside
the basement wall.
FIG. 62.--House drain with outside vent, and running trap placed
outside the basement wall.]
The openings at _E_ and _A_ at each end of the stack permit a constant
circulation of air for ventilation. The length of the stack and its
location causes it to act as a chimney and the draught produced takes
the air in at _E_, and discharges it at the top. In large houses there
is sometimes added a vent stack to produce further ventilation, but
in the average dwelling the arrangement here shown covers the common
practice.
In Figs. 61 and 62 are shown in detail two methods of arranging
the sewer connections in the basement to permit of the removal of
obstructions in case the pipes at any time become stopped. The trap,
vent, etc., are easily recognized. With the arrangement as shown in
Fig. 62, the clean-out is so placed as to give access to the inside
of the pipe. Should an accumulation or obstruction of any kind become
lodged in the pipe, the stop in the clean-out is removed and a
flexible metal rod is used to remove the stoppage. The trap outside the
wall has an opening through which the obstruction may be reached in
case it cannot be removed from the first clean-out. The disadvantage in
using the outside trap, as here shown, is that it can be reached only
by excavation.
Fig. 61 shows another common method of installation. Here the trap is
placed inside the basement wall. This gives an easier means of opening
the trap than Fig. 62 affords and accomplishes the same purpose. The
connections with the stack are the same as in Fig. 62. Obstructions in
the sewer pipe are most likely to become lodged in the trap and for
this reason the trap should occupy a position that is reasonably easy
of access.
The outside trap as described above is quite generally installed in
buildings of all kinds, but its use is by no means universal. In some
communities it is not used at all, and many plumbers consider it only
an added means of causing stoppage and an extra expense to install.
The object of the outside trap is to keep the air of the street sewer
from entering the house drain. It is at once inferred that the air
of the street sewer is more dangerous than that of the house drain.
The street sewers, however, are ventilated at each street corner and
at each manhole. There cannot then be much difference in the air of
the two places. The traps on the fixtures that prevent sewer gas from
entering the house would be just as efficient if the outside trap did
not exist.
While the methods shown in Figs. 61 and 62 are considered good
practice, there is considerable objection to the vent being placed near
the dwelling, because of the sewer gas that is forced out, whenever
a sudden discharge of water goes into the drain. Each time a closet
is flushed, a large volume of water enters the stack and completely
fills the pipe. When this occurs, the descending water forces out the
air of the pipe ahead of it, and a gush of offensive air filled with
sewer gases is forced out of the vent. It is evident that such a vent,
located near an open window or where it will reach the nostrils of the
inhabitants is a thing not greatly to be desired.
Outside traps when placed near the surface sometimes freeze. The
circulation of air through the vent is occasionally sufficient in cold
weather to freeze the water and stop the trap.
[Illustration: FIG. 63.--Corporation cock with lead connecting pipe.]
=Water Supply.=--The water supply taken from the street main is
conducted to the house by the pipe shown in Fig. 58, at _C_. This pipe
is generally of lead as piping of that metal is the most durable for
underground work. Iron used under the same conditions will last only
a few years. The connection is made with the water main by use of a
_corporation_ cock. This is a special style of cock that is shown in
Fig. 63. In the figure the cock is connected with a short piece of lead
pipe that is used for making connection with the service pipe in the
house.
[Illustration: FIG. 64.--Curb cock as it appears attached to the
service pipe.]
Located at the left of _C_, in Fig. 58, is the _curb-cock_, used
for shutting off the water from the city lot. The curb-cock, being
underground, is reached through an iron tube by means of a wrench
attached to a long iron rod. The curb-cock has a protective covering
in the form of an iron pipe. The lower end of the pipe screws into the
body of the cock. The top end comes just above the grade line of the
curb and is covered with an iron screw-cap. The curb-cock is shown in
detail in Fig. 64. The pipe _B_ is fastened to the valve at _D_ and A
is the screw-cap. In opening and closing the wrench fits over the part
_C_ of the valve.
On entering the building the supply pipe should be provided with a
_stop_ and _waste-cock_ for shutting off the water from the house and
draining the pipes that compose the system of circulation. At _V_, in
Fig. 58, is indicated a stop and waste-cock with the waste pipe _B_
connected with the sewer. This cock is shown in detail in Figs. 65 and
66. The cock is so made that when closed there is a small opening at
_A_, that allows the water from the system to escape through the waste
pipe.
From the water supply, the cold-water pipes may be traced in the
drawing directly to each of the fixtures of the house. The hot-water
pipe leaves the range boiler at the top and connects with each fixture
using hot water, thus making the circuit complete. Details of the
piping which provides hot water is described under range boiler, page
116.
[Illustration: FIG 65.--Stop and drain cock with lever handle.]
[Illustration: FIG. 66.--Stop and drain cock with =T= handle.]
WATER COCKS
The development of modern plumbing has brought about the use of a
great number of household mechanical appliances, that have received
trade names little understood by the average person. The lack of
distinguishing terms, or language in which to describe plumbing
fixtures, often leads to embarrassment, when such articles are to
be described to workmen. Common household valves and cocks are so
classified by the trade, that mistakes are often made in their
designation, because of a limited knowledge of the use of the various
articles. A little consideration of the different classes of fixtures
will make it possible to state to a tradesman the exact article in
question.
The term _valve_ is intended to define an appliance that is used to
permit, or prevent, the passage of a liquid through the opening or port
which it guards. The term is so general in its application that there
are hundreds of different kinds of valves. Even for a single purpose
there are many styles of a given kind.
A _cock_ was originally a rotary valve or spigot used for drawing
water. Today there are many kinds of cocks that are not rotary in their
movement.
It would be impossible in this work to describe in detail all of
the kinds of cocks and valves used in household plumbing. It will,
therefore, be the aim to confine attention to one article of a type
and to choose such examples as are in general use and that are good
representatives of their classes.
[Illustration: FIG. 66_a_.--Kitchen sink with Fuller bibb-cocks.]
=Bibb-cocks.=--On the kitchen sink, the water faucets, such as those
shown in Fig. 66_a_, are termed bibb-cocks by the plumber. If the
nozzle is plain, it is a _plain bibb_. If the nozzle is threaded so
that a hose connection may be attached as in Fig. 67, it is a _hose
bibb_. Bibb-cocks are found in three general styles: compression bibbs,
ground-key bibbs, and Fuller bibbs. The compression bibb takes its
name from the method of closing the valve. Fig. 68 gives an example
of its mechanical construction. This is a plain _solder bibb_ because
the shank _A_ is to be attached by a solder joint. If the part _A_
contained a thread to make a screw joint, such as Fig. 67, it would
be a plain, compression, _screw bibb_. Fig. 68 is another style of
compression bibb-cock, largely used on sinks; this cock, being finished
with a flange, is a _compression flange bibb_.
[Illustration: FIG. 67.--Compression hose bibb.]
[Illustration: FIG. 68.--Compression flange bibb.]
[Illustration: FIG. 69.--Cross-section of plain compression bibb-cock
for a solder joint.]
Fig. 69 shows quite clearly the mechanical arrangement of the
compression cock. When the handle is turned the nut _C_ lifts the valve
from its seat _B_, allowing the water to escape. The piece _D_ is
generally made of composition rubber that may be bought at the dealers
for a trifling amount but it may be replaced temporarily with a piece
of leather. The part _E_ is packing, to keep the water from leaking
out around the stem. The packing may be obtained from the dealer
especially for the purpose or it may be made of a disc of sheet rubber.
In fact, anything that can be put into the space will answer the
purpose temporarily. The valve is closed by compression, hence the name
compression cock. All cocks made to open and close in the same manner
are compression cocks.
[Illustration: FIG. 70.--Cross-section of plain self-closing bibb-cock
for lead pipe.]
[Illustration: FIG. 71.--Cross-section of lever handle, plain bibb.]
[Illustration: FIG. 72.--Cross-section of plain Fuller bibb for lead
pipe.]
=Self-closing Bibbs.=--In Fig. 70 is one example of the many styles of
self-closing bibb-cocks. When the handle of this cock is turned, the
steep-pitched screw _A_ opens the valve and at the same time compresses
the spiral spring _B_, when the handle is released, the valve is
pressed back on its seat by the spring. Self-closing cocks are used to
prevent the waste of water at drinking fountains, wash basins and other
places where the water is apt to be left running through carelessness.
=Lever-handle Bibbs.=--Fig. 71 is an example of the _lever-handle_,
_ground-key_ bibb-cock. The key is the piece _A_, which is tapered and
forms a ground joint with the part _B_. The cock takes its name from
the form of the handle. The term ground-key means that the key has been
ground into place with emery dust. This cock is kept from leaking by
adjustment of the screw _C_.
=Fuller Cocks.=--These cocks take their name from their inventor. They
are made to suit every condition for which water cocks are used. Their
universal use attests to their utility and excellence in service. Fig.
72 shows the principle on which all Fuller cocks work. The varying
conditions under which the cocks are used require a great many forms,
but the working principle is the same in all. In these cocks, the
valve is a rubber plug or ball that is drawn into the opening by an
eccentric piece attached to the handle. The piece _D_ in the drawing
is the rubber plug that is drawn against the opening by the crank _B_,
which is worked by the lever handle _A_. This cock may be repaired, in
case it leaks, by unscrewing it at the joint nearest the plug. A wrench
and a pair of pliers are all the tools required. The pieces _D_ must
be obtained from the dealer. The part _J_ is the packing that keeps
the water from leaking out around the stem. The screw-cap _H_ forces a
collar _I_ down on the packing to keep it water-tight.
[Illustration: FIG. 73.--Repairs for Fuller cocks.]
The parts for the Fuller cock that may be obtained for repair are shown
in detail on Fig. 73. The ball, which appears in Fig. 73 at _D_, is the
part that receives the greatest amount of wear. If the cock at any time
fails to stop the flow of water, a new ball may be put in place by the
aid of a wrench and a pair of pliers. The water being first shut off
from the system, the cock is unscrewed and the cap _E_ removed with a
pair of pliers. The worn ball is then removed and a new one substituted.
=Wash-tray Bibbs.=--A special style of cock is made for laundry wash
trays in both the Fuller and compression types. Of these the Fuller
type is the most convenient as the handle is placed on the side and but
one movement is required to open the cock. This style of cock is used
on the wash trays shown in Fig. 83.
=Basin Cocks.=--Water cocks for wash basins are made in two general
types--the compression and the Fuller types of cocks. Their mechanism
is much the same as for other similar styles adapted to the use for
basins. The self-closing cocks used so largely on wash basins are
compression cocks. Fig. 74 is an example of Fuller basin cock in
general use. Compression cocks for the same purpose are shown on the
wash basin in Fig. 90.
[Illustration: FIG. 74.--Fuller basin cock.]
=Pantry Cocks.=--In general form, pantry cocks are the same as those
used for basins except that the outlet is elongated.
[Illustration: FIG. 75.--Sill cock in place attached to the water pipe.]
[Illustration: FIG. 76.--Cross section of sill cock.]
=Sill Cocks.=--As a means of attaching garden hose or lawn sprinklers,
sill cocks are placed on the side of the building at any place
convenient for their use. Fig. 75 illustrates the method of attaching
the cock to the water supply. Fig. 76 shows in cross-section its
mechanical arrangement. The part _A_ is screwed into the water supply,
and _B_ furnishes the hose attachment. The valve is operated the same
as any other compression valve. In Fig. 75 the cock is shown at _A_
with a garden hose attached. The pipe to which _A_ is attached passes
into the basement and connects to the water supply. The stop-cock _B_
is used to shut off the water. When the stop-cock _B_ is closed, _A_
should be opened, so that the pipe will drain. If this is neglected
during freezing weather, the pipe is apt to freeze and burst.
=Valves.=--The distinction between a cock and a valve is not at
all definite. Custom has determined that in certain places a cock
shall stop the flow of a liquid but in another place, perhaps of a
similar nature, a valve shall accomplish the same purpose. The chief
distinction between a cock and a valve is that of its external form.
In Figs. 77, 78 and 79 are three examples of valves that are very
generally used on pipes carrying any kind of fluid. The valves are
shown in cross-section to display the arrangement of the mechanism.
[Illustration: FIG. 77.--Cross-section of globe valve with detachable
valve disc.]
[Illustration: FIG. 78.--Cross-section of angle globe valve.]
[Illustration: FIG. 79.--Cross-section of gate valve.]
Fig. 77 is an example of the common _globe-valve_. The name was
originally intended to define a valve the body of which was in the form
of a globe. The hand-wheel _H_, attached to the screw-stem _S_, raises
the valve _A_ when desired. The valve makes close contact with the
seat _C_, by means of a composition rubber disc _B_. The disc _B_ may
be renewed when worn out as in the case of the radiator valve already
described.
Fig. 78 represents an _angle globe-valve_. In general construction it
is quite similar to Figs. 14 and 15, but the valve _V_ in this case
is a cone-shaped piece of brass, which makes a seat in a depression
provided for it. The valve _V_ and the seat are formed as desired and
then ground into contact with emery dust or other abrasive material, to
assure a perfectly tight joint. When this valve becomes worn and begins
to leak, it may be repaired by regrinding, but such work requires the
services of a pipe-fitter. The tendency of modern practice is to use
valves with the detachable discs, such as that of Fig. 77, because they
are easily repaired.
The valve shown in Fig. 79 is known as a _gate-valve_. The upper part,
including the screw and stem, is the same as the globe style but the
valve proper is made in the form of two flat gates _A-A_. When the
valve is closed, as it appears in the drawing, the gates are forced
against the seats by the cone-shaped piece _B_, which acts as a wedge,
to tightly close the opening. When the hand-wheel is turned to open the
valve, the gates are raised and are taken entirely out of the path of
the flowing liquid. Gate-valves are used in places where it is desired
to obstruct the flow as little as possible. They are somewhat more
expensive than globe-valves but are considered worth the extra expense
in service.
=Kitchen and Laundry Fixtures.=--The development in modern plumbing has
wrought many changes in the styles of household fixtures but none has
been so great as that in the kitchen sink. The old style, insanitary,
wooden sink has been almost entirely replaced by those made of pressed
steel or enameled iron. They are made in every desired size and to
suit all purposes. They may be plain or galvanized as occasion may
require, or the enameled sink is obtainable at a very slight addition
in price. The enameled sink has reached a degree of perfection where
its durability is unquestioned, and as a consequence kitchen furniture
is vastly improved at but little advance in cost.
[Illustration: FIG. 80.--Model kitchen.]
[Illustration: FIG. 81.--White enamel kitchen sink.]
A modern kitchen in which gas is used as fuel is shown in Fig. 80.
Simplicity and neatness of arrangement are the noticeable features.
This kitchen is intended to suit the average-sized dwelling and
contains all necessary plumbing, cooking and heating apparatus. The
hot-water boiler is here shown attached to an instantaneous heater. The
common kitchen sink is supplemented with a slop sink and covered with
a drain board. This simple kitchen may be elaborated to any extent.
Fig. 81 shows a kitchen sink of white enamel with two enameled drain
boards. The drain boards are sometimes covered with perforated rubber
mats.
[Illustration: FIG. 82.--Model laundry.]
[Illustration: FIG. 83.--Enamel wash trays in a basement laundry.]
In Fig. 82 is shown an example of the modern basement laundry. The
wash-boiler heater is shown on the left. An automatic instantaneous
water heater is on the right. The stationary tubs or wash trays occupy
the center of the picture. In detail these wash trays appear in Fig.
83. These are enamel-covered ware and are provided with the wash-tray
bibb-cocks described above. This type of plumbing represents the most
modern of sanitary arrangements.
THE BATHROOM
With the present-day improvements in plumbing, and the perfection
in the manufacture of porcelain and enameled iron, the bathrooms of
houses of moderate cost have become places of cleanliness, attractive,
relatively free from offending odors and supplied with all necessary
sanitary fixtures.
[Illustration: FIG. 84.--Model bath room for the average dwelling.]
Enameled iron has reached a state of perfection where it rivals
porcelain in beauty. The forms of the various bathroom pieces have been
modeled for convenience in use and grace of form, at the same time the
strife of the designer has been to produce articles that not only look
well but are convenient and easily kept clean.
Bathrooms need not be expensive in order to be convenient, attractive
and useful. The bathroom shown in Fig. 84 is such as is installed in
dwellings of moderate price. It possesses every feature necessary
to usefulness and comfort. In this room the furnishings are all of
enameled iron. The floor is covered with linoleum and the wainscoting
with enamel paint.
=Bath Tubs.=--Bath tubs are made in sizes that vary in length from
4-1/2 to 6 feet. They are constructed in a variety of forms and of
materials to suit all conditions of service. For domestic use they
are very generally made of enameled iron. This form of construction
produces serviceable and handsome furnishings for the bathrooms of the
modest house as well as for the sumptuous bath of the most pretentious
residence. An elaboration of Fig. 84 might include the Sitz bath
shown in Fig. 85 and the fittings may be chosen from a great variety
of forms. The recent styles of enameled tubs are, in design, much
handsomer than those with the roll rim and in form such as permits a
clean room with the minimum of labor. They are also provided with more
convenient water and drainage fixtures.
[Illustration: FIG. 85.--Sitz bath.]
The tub of Fig. 86 sets flat on the floor and makes a close joint with
the wall. It thus prevents the accumulation of dust that is difficult
to remove. In addition the fixtures are arranged in a more commodious
manner and the general appearance is most pleasing. The arrangement
of the fixtures in Fig. 87 gives still greater convenience and being
arranged with a shower and protecting curtain, provides all of the
conveniences of a luxurious bath without greatly increased cost over
the simple tub. The fixtures in this design are all in position of
greatest convenience and attached to pipes that are concealed in the
wall.
[Illustration: FIG. 86.--Enameled iron bath tub.]
[Illustration: FIG. 87.--Bath tub with shower.]
The fixtures usually provided with the tub are double Fuller or
compression cocks for hot and cold water, the overflow and strainer,
for the discharge of the water into the sewer in case the tub
overflows, and a drain and bath plug.
The double Fuller cock is shown in Fig. 88. It is made to open
and close by the same sort of mechanism as is shown in Fig. 71, a
description of which appears on page 90.
[Illustration: FIG. 88.--Double Fuller cock for bath tubs.]
The overflow is shown in detail in Fig. 89. The part _A_ appears inside
the tub. It is made water-tight around the edge _C_ by a rubber washer
that is clamped tight to the surfaces by the nut _B_. In case of
leakage, the overflow may be removed for repair by unscrewing the union
attached to the piece _D_ and removing the nut _B_.
[Illustration: FIG. 89. FIG. 89_a_.
FIG. 89.--Overflow attachment for bath tubs, lavatories, etc.
FIG. 89_a_.--Drain attachment for bath tubs, lavatories, etc., showing
locknut and union connection.]
The drain-pipe connection is shown in Fig. 89_a_. The plug _D_ and the
flange _A_ show inside the tub. The flange is made water-tight by a
rubber washer that the nut _B_ clamps tight to the tub. The part _C_
is a union which permits the tub to be detached from the drain pipe.
Repairs to this joint may be made as in the overflow.
[Illustration: FIG. 90.--Old style marble finished lavatory.]
[Illustration: FIG. 91.--Types of lavatory plumbing not now used in
good practice.]
=Wash Stands and Lavatories.=--Wash stands for bathrooms are obtainable
in many forms, either plain or ornate, to suit every condition and
style of architectural finish.
[Illustration: FIG. 92.--Enameled iron wall wash basin.]
[Illustration: FIG. 93.--Enameled iron pedestal wash basin.]
They are made in marble, porcelain and enameled iron, the last being
the most commonly used. They are made to suit the part of the room to
be occupied, whether that is against a wall, a corner, or to stand on
a pedestal on the floor. Those intended to fasten to the wall may be
supported by brackets or suspended at the back from pieces secured in
the wall.
In Figs. 90 and 91 are shown samples of marble-finished wash basins.
In former years basins of this type were very much in use, and until
the introduction of the modern porcelain and enameled ware, it was the
highest type of sanitary plumbing. The water cocks and traps are of the
same style and grade as appear on the most modern examples of enameled
ware of Figs. 92, 93 and 94. The water cocks used in Fig. 90 are of the
compression type. All of the others are of the Fuller type. The basin
in Fig. 93 is provided with extra shut-off cocks on the water pipe
under the basin. They are added to the plumbing merely as a convenient
means of shutting off the water for repair. The wash stand is usually
provided with hot and cold water cocks, a waste pipe with its traps and
overflow connections.
[Illustration: FIG. 94.--Corner wash basin.]
=Traps.=--The waste pipes from the wash basin and bath tub are always
provided with some form of trap, to prevent air from entering the room
from the sewer, charged with offending odors. Traps are made in many
forms, but the purpose of all is to prevent the escape of sewer gas.
The plain trap _S_, shown in Fig. 95, is that used under the basin in
Fig. 91. It makes a tight joint by means of the nut _B_ and a rubber
washer as in the case of other joints of the kind. The parts _C_ and
_E_ are unions that permit the pipe or bowl to be removed without
disturbing the remainder of the plumbing. From the form of the trap
it will be seen that the U-shaped part below the dotted line _F_ will
always remain full of water and so prevents the escape of air from
the sewer. In case the trap becomes stopped the obstruction will
likely become lodged in this part of the pipe. To clean the trap the
screw-plug _D_ is taken out with a pair of pliers and the obstruction
removed with a wire.
The traps used in Figs. 90 and 92 are the same in principle as Fig. 95
but are made to discharge into a pipe placed in the wall instead of
under the floor. The trap in Fig. 94 is a form known as the bottle-trap
that is sometimes used in the more expensive plumbing.
[Illustration: FIG. 95.--The S trap of nickel-plated brass tubing.]
[Illustration: FIG. 96.--The Bower non-siphoning trap.]
[Illustration: FIG. 97.--The drum type of non-siphoning trap.]
[Illustration: FIG. 98.--An S trap made of lead pipe.]
Another style much used with lavatories is the Bower trap shown in Fig.
96. In this trap the water comes down the pipe _B_ and pushing aside
the hollow rubber ball _A_, enters the space surrounding it and is
discharged at _C_. The ball, being light, is held against the end of
the pipe by the water and acts as a stopper to prevent evaporation from
taking place. Open traps, such as Fig. 95, if left standing for a long
time, may lose sufficient water by evaporation to destroy the water
seal and allow the sewer gas to escape. In the use of the Bower trap
such occurrence is much less likely to take place.
Fig. 97 is another trap much used on sinks; it is known under the
trade name of the Clean Sweep trap. The part _C_ is much larger than
the common trap and the water seal is less likely to be broken. The
clean-out is larger and the interior is easy of access in case of
stoppage.
The simplest and most commonly used trap in cheap plumbing is that of
Fig. 98. It is a lead pipe bent in the form of an _S_. It is the same
in shape as Fig. 95 and performs its work as well but does not have the
means of detachment shown in the latter. Traps of many other forms are
in use but all have the same function to perform and the mechanical
make-up is much the same as those described.
[Illustration: FIG. 99.--A method of bath-room plumbing using the drum
trap.]
The plan of attachment of the various bathroom fixtures of the soil
pipe must always depend on local conditions. The object is to conduct
the waste water to the sewer in such a way as to give the least
opportunity for stoppage and to prevent sewer gas from escaping into
the house. To accomplish this purpose the pipes and traps are arranged
according to a plan proposed by the architect, plumber or other person
familiar with the principles of plumbing. Since these pipes are
placed in the walls and under the floors, where they are not readily
accessible, it is necessary that their arrangement be made with care
and that the workmanship be such as to assure correct installation.
In Fig. 99 is shown a common method of connecting bathroom fixtures
with the sewer. The drawing shows a bathroom with the floor broken away
to show the pipe connections with the bath tub, wash basin and closet.
The overflow pipes _O_ and _V_ and the drain pipes _D_ and _R_ from
the wash basin and bath tub empty into a large lead drum-trap _T_, set
under the floor. This trap takes its name from its shape. It is set
in position as dictated by the conditions under which it is used. The
nickeled plate _P_, screwed into the top of the trap, comes just above
the bathroom floor. This plate is easily removed in case of stoppage.
It is made air-tight by a rubber ring placed under the cover and which
makes a joint with the top edge of the drum.
It will be noticed that the waste pipes from the bath tub and wash
basin enter the trap near the bottom and discharge at the opposite side
near the top. The water will stand in the trap and pipes level with
the bottom of the discharge pipe and thus form a seal that prevents
the escape of sewer gas. This is a common form of non-siphoning trap.
It is non-siphoning because it cannot lose its seal by reason of the
siphoning effect of the water as it passes through the waste pipes
on its way to the sewer. Another form of non-siphoning trap is the
clean sweep trap shown in Fig. 97. Such traps as Figs. 95 and 98 are
siphoning traps, since it is possible, in this form of trap, for the
water to be so completely siphoned that not enough remains to form
a seal. The small drawing, marked _Detail L_, is another method of
connecting the same arrangement of fixtures. The waste pipe enters the
trap as before but discharges immediately opposite. The level of the
water stands in the pipes as indicated by the dotted line.
=Back-venting.=--To prevent the possibility of loss of seal by
siphoning and the escape of sewer gas, traps are back-vented to the
main stack or to a separate vent stack. The venting is accomplished by
joining a pipe to the top of the trap or to some point in its immediate
neighborhood, and connecting this with the main stack or the vent
stack. The water in a trap so vented will be open to the air from both
sides and consequently can never be subject to siphonic action.
In the average-sized dwelling where non-siphoning traps are used,
back-venting is not necessary, but in large houses and in plumbing
where siphon traps are used, vent pipes must be attached to the traps
to assure a satisfactory system.
Fig. 100 furnishes an example of back-venting, applied to the bathroom
shown in Fig. 99. In the former figure the bath tub and wash basin
are connected with the waste pipe by siphon traps. A siphon trap may
lose its seal in two ways: by self-siphonage, or by aspiration caused
by the discharge of the water from other fixtures. In the discharge
of the siphon trap, such as _B_, in Fig. 100, the long leg of the
siphon, formed by the discharge pipe, may carry away the water so
completely that not enough remains in the trap to form a seal. Again,
the discharge of the water from the bath tub through the waste pipe
tends to form a vacuum above it and in some cases the seal in _B_
is destroyed by the water being drawn into the vertical pipe. The
possibility of either of these occurrences is prevented by back-venting.
[Illustration: FIG. 100.--An example of back-vented plumbing as applied
to the bathroom.]
In Fig. 100, a pipe from the main stack is connected with the bend of
the trap at _B_ and also to the waste pipe outside the trap at _T_. A
vent is also taken from the drain _C_, at a point just below the trap
in the closet seat. The object of all of the vents is to prevent the
tendency of the formation of a vacuum from any cause that will carry
away the water seal of the trap and allow sewer gas to enter the house.
The closet seat also contains a trap which will be described later. It
connects with soil pipe _S_, leading to the sewer by a large lead pipe
_C_.
All of the pipes under the floor, leading to the soil pipe, should
be of lead. The pipes above the floor are generally of iron or
nickel-plated brass. All of the connections in the lead pipes are made
with _wiped joints_; that is, the connections are made by wiping hot
solder about the joint, in a manner peculiar to this kind of work, in
such a way as to solder the pipes together. The joints made in this
manner are perfectly and permanently tight. Lead pipes are used under
such conditions, because lead is the least affected by corrosion of any
of the metals that could be used for such work.
=Soil Pipe.=--The soil pipe, of which the waste stack or house drain is
composed, is made of cast iron and comes from the factory covered with
asphaltum paint. It may be obtained in two grades, the standard and
extra heavy. The only difference is in the thickness of the pipe. The
former is commonly used in the average dwelling. One end passes through
the roof and the other end joins to the vitrified sewer tile under the
basement floor. The joints must be perfectly tight, because a leak in
this pipe would allow sewer gas to escape into the house. One end of
each section is enlarged sufficiently to receive the small end of the
next section. The joints are made with soft lead. The pipes are set in
place and a roll of oakum is packed into the bottom of the joint, after
which molten lead is poured into the joint, filling it completely. The
oakum is used only to keep the lead in the joint until it cools. After
the lead has cooled it is packed solidly into the joint with a hammer
and calking tool. The calking is necessary because the lead shrinks
on cooling and makes a joint that is not tight. Well-calked joints
of this kind are air-tight and permanent. _Detail N_ (Fig. 99) shows
the arrangement of the parts of the joint as indicated at _A_. The
blackened portion represents the lead as it appears in the joint.
_Detail M_ (Fig. 99) shows the methods of attaching the closet seat
to the lead waste pipe _C_. The end of the lead pipe is flanged at
the level of the floor, as shown at _C_ in the detail drawing. The
depression _D_, around the connection, is then filled with glazier’s
putty and the seat is forced down tightly in place and fastened with
lag screws.
The pipe _C_, from the closet, and that from the trap _T_, being of
lead, a special joint is necessary in connecting them with the soil
pipe, because a wiped joint cannot be made with cast iron. To make such
a connection the end of the lead pipe is “wiped” onto a brass thimble,
heavy enough to allow it to be joined to the soil pipe by a calked lead
joint. The brass thimble is then joined to the cast-iron pipe by a
calked lead joint.
[Illustration: FIG. 101.--The wash-out closet.]
[Illustration: FIG. 102.--The wash-down closet.]
=Water Closets.=--Water closets are made in a great number of styles to
suit the architectural surroundings and the various conditions under
which they are to be used. Many forms of water closets are manufactured
to conform to special conditions, but those commonly used in the
bathrooms of dwellings are of three general types. The mechanical
construction of each is shown in the following drawings, Figs. 101,
102 and 103 showing respectively in cross-section the principle of
operation of the _washout_ closet, the _washdown_ closet and the
_siphon-jet_ closet.
_Washout Closets._--This type of closet has in the past been used to
a very great extent. It does not perform the work it has to do, so
perfectly as the others, because the shallowness of the water in the
bowl allows it to give off odors, and because it is difficult to keep
clean. The action of the closet is as follows: When the closet is
flushed the water enters the rim at _A_, and the greater portion of
it is washed downward at _B_ to dislodge the contents of the bowl. A
lighter flush is sent through the openings in the side, which serves
to wash the entire surface. The direction of discharge is forward,
where it da
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