File:Mechanics of the household; a course of study devoted to domestic machinery and household mechanical appliances (1918) (14779473235).jpg

Identifier: mechanicsofhouse00keen (find matches)
Title: Mechanics of the household; a course of study devoted to domestic machinery and household mechanical appliances
Year: 1918 (1910s)
Authors: Keene, E. S. (Edward Spencer), b. 1864
Subjects: Heating Lighting Plumbing
Publisher: New York, McGraw-Hill book company, inc.
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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Text Appearing Before Image:
hot-water method ofheating. Fig. 31a is a diagram illustrating the C. A. Dunham systemof vapor heating. It will be noticed that there are no air ventson the radiators. The air from the radiators is ejected througha special form of trap that is indicated in the drawing. Thesetraps permit the water and air to pass from the radiators butclose against the slightly higher temperature of the vapor. Thisassures the condensation of the vapor in the radiators and ex-cludes it from the return pipes. The water returns to the boilerin much the same manner as in the pressure systems already de-scribed but the air escapes through the air eliminator as indi-cated in the drawing. The system is, therefore, under atmos- THE STEAM HEATING PLANT 35 pheric pressure at this point and only a slight amount greaterin the boiler. The water of condensation is returned to the boiler againstthe vapor pressure, by a force exerted by the column of waterin the pipe connecting the air eliminator with the boiler. The
Text Appearing After Image:
Fig. 31a.—Diagram showing the C. A. Dunham Co.s system of vapor heating. main return is placed 24 inches or more above the water line ofthe boiler. It is the pressure of this column that forces thewater into the boiler through the check valve, against the vaporpressure in the boiler. 36 MECHANICS OF THE HOUSEHOLD It might be imagined that the water in the boiler and thatin the air-ehminator pipe formed a ^U-tube/ the vapor pressureon the water surface in the boiler, and the atmospheric pressureon the water in the eliminator standpipe. The slight vapor pres-sure in the boiler is counterbalanced by a column of water in theeliminator pipe. It is this condition that fixes a distance of 24inches from the water line to the return pipe; that is, the forceexerted by a column of water 24 inches high is required to sendthe water into the boiler. The vapor pressure is controlled by means of the pressurestat,which is an electrified Bourdon spring pressure gage, connectedup by simple wiring to t

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