GB1295092A - - Google Patents

Abstract

1295092 Gas turbine engines; air intakes ROTAX Ltd 5 Feb 1970 [19 Feb 1969] 8892/69 Heading F1G The invention relates to a hot air system for supplying heated air to an air jacket disposed around the air intake duct of a gas turbine engine, there being conduit means through which hot air can flow to the jacket from a source thereof such as a tapping from the compressor of the engine, a control valve being disposed in the conduit, the valve being controlled by temperature sensitive means responsive to temperature of intake of air flowing in the duct. In Fig. 3 air is tapped from the engine compressor 101 and supplied through conduit 100 to the air jacket 102 around the engine air intake duct. Two control valves 111, 112 are disposed in the conduit 100, the valves being similar in construction. The valve 111 is shown in Fig.4 and comprises a casing 113 forming part of the conduit 100, a piston member comprising a skirt portion 115 and a head 116 being slidably mounted therein. The piston is also slidably mounted in a fixed housing 119a which defines with the piston head a chamber 120 to which air under pressure may be supplied to control the piston. The piston is formed with an aperture 118 also with a stop 117 which in the closed position of the valve shown abuts the end of the housing 119a, the air under pressure acting against the stop 117 holding the piston in this position. Upon actuation of solenoid 124, the two-way valve 123 opens to allow air under pressure to pass through passage 121 to chamber 120 thus causing the piston to move to the open position in which heated air passes to the jacket space 102. The opening of the valve 112 is controlled in dependence on temperature of intake air flowing through the intake duct as sensed by the device 127. The device 127 is shown in Fig.1 and comprises a mounting 10, a tubular member 12 of material having a high coefficient of thermal expansion and a tubular member 16 of material having a low coefficient of thermal expansion, the member 16 acting at its lower end through a lever assembly 29, 30 against a plug member 31 slidable in casing 27 the plug member in turn acting through a spring-loaded tube member 37 to control the opening of a valve member 32. The inlet 35 of the valve is supplied with air through restrictor 125; a tapping from a point intermediate the restrictor 125 and the temperature sensing device communicates with the chamber 120 of the valve 112. Fluid under pressure is caused to flow through member 16 and discharges through nozzle 24 to induce ambient air-flow through inlet 25 between the tubular members 12, 16.