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Adding to this the wonderful advance in the gas engine field - not only in the automobile type where requirements of lightness, speed, and reliability under trying conditions have developed a most perfect mechanism, but in the stationary type which has so many fields of application in competition with its steam-driven brother as well as in fields where the latter can not be of service - you have a brief survey of the almost unprecedented development in this most fascinating branch of Engineering.

This story has been developed in these volumes from the historical standpoint and along sound theoretical and practical lines. It is absorbingly interesting and instructive to the stationary engineer and also to all who wish to follow modern engineering development. The formulas of higher mathematics have been avoided as far as possible, and every care has been exercised to elucidate the text by abundant and appropriate illustrations.

The Cyclopedia has been compiled with the idea of making it a work thoroughly technical, yet easily comprehendible by the man who has but little time in which to acquaint himself with the fundamental branches of practical engineering. If, therefore, it should benefit any of the large number of workers who need, yet lack, technical training, the publishers will feel that its mission has been accomplished.

Grateful acknowledgment is due the corps of authors and collaborators - engineers and designers of wide practical experience, and teachers of well-recognized ability—without whose co-operation this work would have been impossible.

Table of Contents

By C. L. Hubbard† Page* 11

Systems of Warming-Hot-Air Furnaces-Direct and Indirect Steam and Hot-
Water Heating-Radiators-Exhaust Steam Heating-Ventilation-Heat Losses
-Direct- and Indirect-Draft Furnaces-Furnace Details-Smoke-Pipes-Flues
-Cold-Air Box-Warm-Air Pipes-Registers-Sectional, Tubular, and Water-
Tube Boilers-Circulation Coils-Systems of Piping-Air-Valves-Blow-Off Tank
-Expansion Tank-Back-Pressure Valve-Exhaust Head-Return Pumps and
Traps - Damper Regulators -Vacuum Systems - Fans and Blowers - Factory
Heating-Electric Heating-Automatic Regulators-Air-Filters and Washers-
Heating and Ventilating Schools, Churches, etc.

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INTERIOR OF NEW YORK SHIP BUILDING COMPANY WORKS, CAMDEN. NEW JERSEY, SHOWING HEATER FANS

HEATING AND VENTILATION

PART I

SYSTEMS OF WARMING

Any system of warming must include, first, the combustion of fuel, which may take place in a fireplace, stove, or furnace, or a steam, or hot-water boiler; second, a system of transmission, by means of which the heat may be carried, with as little loss as possible, to the place where it is to be used for warming; and third, a system of diffusion, which will convey the heat to the air in a room, and to its walls, floors, etc., in the most economical way.

Stoves. The simplest and cheapest form of heating is the stove. The heat is diffused by radiation and convection directly to the objects and air in the room, and no special system of transmission is required. The stove is used largely in the country, and is especially adapted to the warming of small dwelling-houses and isolated rooms.

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Furnaces. Next in cost of installation and in simplicity of operation, is the hot-air furnace. In this method, the air is drawn over heated surfaces and then transmitted through pipes, while at a high temperature, to the rooms where heat is required. Furnaces are used largely for warming dwelling-houses, also churches, halls, and schoolhouses of small size. They are more costly than stoves, but have certain advantages over that form of heating. They require less care, as several rooms may be warmed from a single furnace; and, being placed in the basement, more space is available in the rooms above, and the dirt and litter connected with the care of a stove are largely done away with. They require less care, as only one fire is necessary to warm all the rooms in a house of ordinary size. One great advantage in the furnace method of warming comes from the constant supply of fresh air which is required to bring the heat into the rooms. While this is greatly to be desired from a sanitary standpoint, it calls for the consumption of a larger amount of fuel than would otherwise be necessary. This is true because heat is required to warm the fresh air from out of doors up to the temperature of the

rooms, in addition to replacing the heat lost by leakage and conduction through walls and windows.

A more even temperature may be maintained with a furnace than by the use of stoves, owing to the greater depth and size of the fire, which allows it to be more easily controlled.

When a building is placed in an exposed location, there is often difficulty in warming rooms on the north and west sides, or on that side toward the prevailing winds. This may be overcome to some extent by a proper location of the furnace and by the use of extra large pipes for conveying the hot air to those rooms requiring special attention.

Direct Steam. Direct steam, so called, is widely used in all classes of buildings, both by itself and in combination with other systems. The first cost of installation is greater than for a furnace; but the amount of fuel required is less, as no outside air supply is necessary. If used for warming hospitals, schoolhouses, or other buildings where a generous supply of fresh air is desired, this method must be supplemented by some form of ventilating system.

One of the principal advantages of direct steam is the ability to heat all rooms alike, regardless of their location or of the action of winds.

When compared with hot-water heating, it has still another desirable feature-which is its freedom from damage by the freezing of water in the radiators when closed, which is likely to happen in unused rooms during very cold weather in the case of the former system.

On the other hand, the sizes of the radiators must be proportioned for warming the rooms in the coldest weather, and unfortunately there is no satisfactory method of regulating the amount of heat in mild weather, except by shutting off or turning on steam in the radiaators at more or less frequent intervals as may be required, unless one of the expensive systems of automatic control is employed. In large rooms, a certain amount of regulation can be secured by dividing the radiation into two or more parts, so that different combinations may be used under varying conditions of outside temperature. If two radiators are used, their surface should be proportioned, when convenient, in the ratio of 1 to 2, in which case one-third, two-thirds, or the whole power of the radiation can be used as desired.

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