GB737393A - Enclosure air supply system - Google Patents

Abstract

737,393. Ventilation. GARRETT CORPORATION. Sept. 23, 1952 [Oct. 18, 1951], No. 23802/52. Class 137. In an air supply system, particularly for an aircraft compartment, a compressor 9 for ambient air discharges to atmosphere through a cabin supply duct 14 and a cabin exhaust duct 18, 20, 28, 29, the exhaust duct including combustion-power means 26, 27 which drive the compressor, and a valve-controlled duct 12 connects the compressor to the combustion-power means, the air inlet 14 to the cabin also being valve controlled. The compressor 9 receives ambient air at 10 and passes it to a duct 11 which branches at 12 through the check valve 23 to the combustion chamber 26 supplying the gas turbine 27 which drives the compressor 9. The duct 11 further branches at 13, 14, the branch 13 being for supplying pneumatic devices such as the starting equipment for the main engines. The branch 14 leads to the cabin 16 in which the pressure is maintained and regulated by a conventional outflow valve 17. Exhaust cabin air passes through the duct 18 to a positive displacement compressor 43, connected to the transmission shaft 41 of the turbine 27 by a shaft 44, which acts as positive control for the exhaust air outflow and serves to keep the pressure drop across the turbine 27 at a substantially constant value irrespective of the ratio of cabin air pressure to ambient air pressure. The exhaust air is led to atmosphere either through the duct 19, or through the duct 20 and check valve 22 to the combustion chamber 26 and from thence to atmosphere either through the duct 29, or, if the air to be admitted to the cabin needs to be warmed, through a heat exchanger 31, this being determined by a temperature-responsive means 34 controlling a valve 32. The flow of air to the cabin is controlled by a valve 35 having an actuator responsive to conditions in the venturi 36, and further responsive to heat-sensitive means 37 in the turbine exhaust duct 28. Refrigerating means 38 is positioned in the duct 14, the air being cooled thereby when necessary, and to an extent determined by the flow through a bypass 39, the valve 40 being controlled manually or automatically. A valve 47 prevents the formation of a vacuum in the cabin when starting up the air-supply apparatus. The compressor 43 may, at extreme altitudes, operate as a power-delivery device to assist the turbine 27. A conventional starter 42 and electric generator 46 are shown.