GB971163A - Cooling systems for aircraft - Google Patents

Abstract

971,163. Refrigeration; ventilating aircraft. NORMALAIR Ltd. Nov. 22, 1961 [Nov. 26, 1960], No. 40711/60. Headings F4H and F4V. Engine compressor bleed air for cooling and ventilating the enclosure of a supersonic aircraft is cooled by one or more evaporators of a closed circuit vapour cycle system comprising a multistage refrigerant compressor 1, a ram air or fuel cooled condenser 3, expansion valve means, and two or more evaporators each cooled by separate refrigerant flows which communicate with different stages of the refrigerant compressor so that they work at different, predetermined pressures and temperatures. In Fig. 1, the two sections of an evaporator 7 are connected respectively to the first and second stage inlets of a constant speed compressor 1, and expansion valves 10, 11 are controlled by temperature-sensing devices downstream of the two evaporator sections. A capacity control 14, e.g. a manually or automatically controlled restrictor, in line 9 regulates the pressure, and hence the evaporating temperature of refrigerant in the second evaporator section. In a second embodiment (Fig. 2, not shown), the vapour cycle system has a third branch including an evaporator which cools a mixture of cooled engine compressor bleed air and air recirculated from the enclosure. In a third embodiment, Fig. 3, the vapour cycle system comprises a multi-stage variable speed compressor 1 driven by bleed air passing through a turbine 30, an evaporator 7 in one branch cooling the bleed air, and an evaporator 15 cooling recirculated air which is pumped by a fan 33 driven by a bleed air turbine 32. Before reaching the evaporator 7, the bleed air is is cooled by ram air and by fuel in heat exchangers 40, 41, respectively.