GB1316308A - Air conditioning systems and the like - Google Patents

Abstract

1316308 Air conditioning HONEYWELL Inc 15 Oct 1970 49119/70 Heading F4V [Also in Division G3] In an air-conditioning system for a number of separate zones 11-13, air is supplied through heat exchanger 24 and blower 17 and entry into zones 11-13 is controlled by dampers 21 operated by respective pneumatic thermostats 14 providing 0-16 p.s.i. signals to motors 22. The thermostat signals are also transmitted to selector 28 which admits the weakest signal, i.e. that corresponding to the zone of lowest temperature, to a relay 27 (Figs. 3 and.4) controlling supply of heating fluid to heat exchanger 24 via a valve 26 biased to an open condition. When the signal fed to relay 27 is below 3 p.s.i., the relay provides a falling output pressure at 30 thereby allowing valve 26 to increase flow to the heat exchanger. With signals between 3 and 4 p.s.i., the output at 30 remains constant, and with signals above 4 p.s.i. the output increases, thereby causing valve 26 to decrease flow to the heat exchange. In a modification, each zone connects additionally with a. cooled air supply controlled by further dampers (83) which are operated by the same thermostat as the corresponding warm air damper. A selector (88) similar to selector 28 admits the weakest signal to relay 27 as above, but also admits the strongest signal, i.e. that corresponding to the zone of highest temperature, via inverting relay (90), i.e. one providing 16-0 p.s.i., to a relay (92) corresponding to relay 27, and relay (92) controls the flow of cooling medium via valve (86) to cooler (84) in the cooled air supply duct. Valve (86) is controlled similarly to valve 26 above but the critical pressure range about which the cooling system cycles is 12-13 p.s.i. as opposed to 3-4 p.s.i. for the heating system.