GB713013A - Air conditioning system - Google Patents

Abstract

713,013. Air conditioning systems. GARRETT CORPORATION. Aug. 30, 1951 [Sept. 2, 1950], No. 20476/51. Class 137. [Also in Group XIII] An air conditioning system comprises air compressing means ; means for conducting air under pressure from the compressing means to an enclosure; means for cooling the air prior to delivery to the enclosure, including means for cooling the air by converting energy therein into mechanical energy ; bye-pass means around the energy converting means ; and means for controlling the bye-pass means in accordance. with a predetermined load condition on the compressing means. As shown in Fig. 1, a primary compressor 10 draws in air through an in'et 12 and de'ivers it to an aircraft cabin 16 partly through a conduit 13 and partly through a conduit 14 which has a valve 29 under control of a thermostat 32. Air passing through the conduit 13 is cooled in a first heat exchanger 19 and then passes through a secondary compressor 23 and a second heat exchanger 18. From the heat exchanger 18 the air passes through a mechanical energy converter 21 where it is further cooled or in certain conditions through a bye-pass conduit 27 which has a valve 28 also controlled by the thermostat 32 and finally through a device 24 for removing condensed water and into the cabin 16, mixing with air supplied through the conduit 14. A control 34 responsive to the pressure differential between the inlet and outlet of the primary compressor 10 is arranged to override the control of the thermostat 32 on the valve 28 in the byepass 27 and to prevent overloading of the primary compressor 10 opens the valve 28 when the pressure differential reaches a predetermined value, A conduit 25 with a valve 26 is arranged to bye-pass the secondary compressor 23 and is arranged to open during the opening of the valve 28. The converter 21 is adapted to drive the secondary compressor 23 and fans 38 and 39 are provided to give a flow of cooling air through the heat exchanger 18 during times of low ram pressure or when the aircraft is on the ground. In a modification (Fig. 2) the first heat exchanger is dispensed with and an aftercooler 40 is placed in the conduit between the heat exchanger 18 and the mechanical energy converter 21, the cooling air for the cooler 40 being exhausted air from the cabin 16 supplied through a conduit 41. This flow of air is controlled by a valve 42 which is arranged to be opened manually or automatically when the aircraft is on the ground for example by electrical means operated by the lowering of the landing wheels of the aircraft.