GB588535A - Improvements in or relating to hot air heating systems - Google Patents

Abstract

588,535. Controlling ventilation. ABBEY, A. (Miles, J. C.). Feb. 27, 1945, No. 4926. [Class 137] [Also in Groups XIII and XXIV] In a hot-air heating system with an air heating furnace or other unit 10, and a motor 17 driving a blower 15 which circulates air from the area to be heated through a return duct 12 to the air heating unit 10 and then through a conduit 11 to the area to be heated, a temperatureresponsive unit 25 mounted in the return duct 12 operates a change-speed device 20 to increase or decrease the speed of the blower as the temperature in the return duct decreases or increases respectively. The change-speed device (see Group XXIV) comprises a pulley composed of a part 30 fixed to a motor shaft 18 and a part 31 axially movable relatively to the fixed part 30 against the action of springs 35 by means of levers 53, which are moved through a spring 51, rod 52, and bellows 46, by the expansion of a fluid, e.g., ethyl chloride, in the chamber 40 of the temperature responsive device (see Group XIII). This chamber 40 has an extension 42 which screws on to the movable part 31 of the pulley so as to enable adjustment of the temperature range in which the effective diameter of the pulley is varied. When the distance between the pulley parts-30, 31 exceeds a certain amount, the belt 26 engages a ball race 38, and the blower stops. Air is caused to flow through the annular space between the chamber 40 and a surround ing shell 60 by means of fan vanes 63. In a modification, the spring 51 is omitted. A thermostat 21 operates the furnace dampers.