. Power, heating and ventilation ... a treatise for designing and constructing engineers, architects and students . eservoir and with the steam valve ordiaphragm. When the temperature rises the disk A expands, pressingagainst M and thus opening the valve /. This allows the air topass from H into / through the chamber K, and thus admits thepressure to the steam valve and closes it. When the temperaturefalls, the disk contracts and the valve / is closed by the actionof a coil spring. The air pressure is relieved from the steam SPECIAL DEVICES 241 valve through the small exhaust valve L. Fig. 164
. Power, heating and ventilation ... a treatise for designing and constructing engineers, architects and students . eservoir and with the steam valve ordiaphragm. When the temperature rises the disk A expands, pressingagainst M and thus opening the valve /. This allows the air topass from H into / through the chamber K, and thus admits thepressure to the steam valve and closes it. When the temperaturefalls, the disk contracts and the valve / is closed by the actionof a coil spring. The air pressure is relieved from the steam SPECIAL DEVICES 241 valve through the small exhaust valve L. Fig. 164 shows thethermostat as it appears enclosed in its casing. Hot-air Thermostat.—Fig. 165 is a side view of the Johnsonthermostat especially designed for insertion in the side of an airduct. These are used in connection with main or primary heatersat the fan, and are for regulating the temperature of the air usedfor ventilation. All thermostats have a certain range of regulation, generallyfrom 60° to 80°, so that they may be set to keep the room atany temperature desired within these limits. A change in tem-. Fig. 167. Powers Pneumatic Valve. perature of about 1° is sufficient to cause a thermostat to actwhen in proper adjustment. Valves.—^The pneumatic valves which replace the usual shut-off valves on the radiators are similar in construction to theordinary globe or angle valve, except the stem slides up anddown instead of being threaded and running in a nut. The topof the stem connects with a flat plate which rests against a rubberor corrugated metal diaphragm. The valve is held open by aspring, and is closed by admitting compressed air to the spaceabove the diaphragm. In connecting up the system, small con-cealed pipes are carried from the air reservoir to the thermostat,which is placed upon an inside wall of the room, and from hereto the pneumatic valve at the radiator. 242 HEATING AND VENTILATING PLANTS Fig. 166 shows a section through a pneumatic steam is the
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectventilation, bookyear
