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This reduction of area should not be quite as much as the area of the branch pipe.
The further the air travels from the fan, the less force it has, and this should be compensated for, as far as may be, by slight allowances in area as the various branches are taken off, bearing in mind that this allowance should finally lead up to 25 per cent excess of outlet areas over the area of the main pipe at the fan.
In offices and comparatively small rooms the outlets are usually in the form of rectangular registers placed in the side walls near the ceiling. The area of these should be from two to three times the area of the pipe lead
Branch leading from ing to them.
Main Heating Pipe. Fig. 59 shows the plan of the arrangement of the heating system of the machine shop
k 12" and Fig. 60 a cross-section of the same, giving the diañeters of the pipes at various distances from the heaters; and the number, direction, diameter, and location of the openings, not only for the machine shop proper but for the carpenter shop, wash rooms, etc.
The heating apparatus consists of a rectangular iron case containing a large number of steam pipes of practically U-shaped form, inverted and connected to a cast iron base in such a manner that one leg of the pipe connects with the space through which the steam is admitted and the other leg connects with the space from which the drip is taken. These pipes should be located as close to each other as practicable, the rows of pipes being set “staggering” so as to break up the currents of air. The casing which surrounds them and connects with the inlet of the fan should also be formed as closely to the pipes as may be, in order that all air which is drawn through may come into close contact with the heating surfaces of the pipes.
It is customary to allow one foot of 1-inch pipe, or its equivalent, to each 100 to 150 cubic feet of contents of the building to be heated, when all the air is taken from out-of-doors. In the case under consideration, with one half or more of the air from within the building the higher figure would probably be ample. At the end opposite the fan are located dampers for regulating the amount of air supply. One of these may be connected with a cold-air duct from out-of-doors, where necessary.
Referring to Figs. 59 and 60 the location of the apparatus is seen to be in the gallery floor, near the center of the building. The fan has two discharge
openings, one downward for warming the side wings of the first floor, and one at an upward angle for the same service on the gallery floor. The returning
currents of air flow into the central portion of the building and warm that portion in their upward course.
Two sets of apparatus are used, for the reason that the traveling crane over the central portion of the shop prevents convenient connections between the two sides; and further, that the space to be heated is so large that the questions of convenience and economy are best met by this arrangement.
The apparatus on the side nearest the power house will require a fan with a wheel say 100 inches diameter by 52 inches wide, and running at about 185 revolutions per minute. This will supply from its downward opening the pipes for the main floor, including that leading to the carpenter shop and to the wash room on the first floor; and from its upward opening it supplies the pipes from the gallery floor, including one for the wash room on the second floor.
The apparatus on the opposite side of the shop should have a fan with a wheel say go inches diameter by 48 inches wide, running at about 205 revolutions per minute. The pipe connections are similar to the first apparatus, except that there are no long branch pipes to be provided for. Hence, while a 36-inch pipe is necessary for the side toward the power house, in order to warm the carpenter shop and the wash rooms, one of 29 inches diameter will be quite sufficient for the opposite side. It should be said that the dimensions given on the drawings are from actual calculations, taking into consideration all the circumstances of the form and dimensions of the buildings, and they will probably be found correct in practice as in theory.
The openings for the discharge of warm air into the building are directed toward the outer walls and downward at an inclination of about 10 degrees. This arrangement is clearly shown in the drawings, Figs. 59 and 60.
The pipes should be well riveted as they are put up, and securely fastened so that they may not be loosened by any jarring or vibration, either of the building or that caused by the pressure of air passing through them.
The fans may be driven by an electric motor or by an engine attached to cach fan; or, if preferred, by belts from the main line of shafting. Any of these methods is efficient and has its particular advantages. If an engine is used, the large fan will require it to be of about 27 horse-power and that for the other fan should be of about 20 horse-power.
Live steam being used for heating, the large apparatus will probably require a supply pipe of 6 inches in diameter and the smaller one of 5 inches. The apparatus should be so constructed that a section of it may be separately connected for using the exhaust steam from the fan engine. In the same way the exhaust from the main engines of the works may be utilized and thus save a considerable portion of the live steam required.
In arranging for heating the foundry, different conditions are met with. With the exception of the chipping and pickling room heat is required hardly more than half the time, that is, during the forenoon, and perhaps for an hour or more after the dinner hour, as the heat from the cupolas is considerable.
The general plan of the system is the same as that employed in the ma
chine shop. The apparatus requires but little room on the floor and consists of a fan having a wheel about 78 inches in diameter and 24 inches wide, running at about 400 revolutions per minute, and will require about 6 horse-power to drive it.
An arrangement of pipes can, of course, be made whereby the chipping and pickling room could be warmed independently of the foundry proper, but it would probably not be necessary.
Figs. 61 and 62 show the arrangement of the foundry system of heating, with diameters of the pipes and openings. It will be preferable to run this fan by an electric motor or a small engine, and since these fan blowers for heating purposes are now made with simple and compact engines attached to them, which require very little attention, aside from starting, stopping, and oiling up, they are very convenient in such situations.
It is always important to have the heater as near the space to be warmed as possible.
The office building, including the pattern shop, drawing room, and tool department, is heated by an apparatus located in the tool room and forming a separate system.
Fig. 63 gives plans of the first floor and Fig. 64 that of the second
floor. Fig. 65 is a longitudinal section through the building. A heating apparatus of the same size and capacity as that used in the foundry is employed. It may be driven by a separate engine, or a motor, or belted from the shaft which drives the machines in
Fig. 61. — Cross Section through Foundry, Cupola, Platforms, etc.