| 摘要 |
1,076,510. Fluid-pressure servomotor systems, fluid regulation. ROLLS-ROYCE Ltd. May 13, 1966, No. 21483/66. Headings G3H and G3P. [Also in Division F1] . gas gas turbine engine is provided with means for shutting off fuel flow when surging conditions arise in the engine compressor. As shown, an engine 10 has a low pressure compressor 12 and high pressure compressor 13, some of the air from the compressor 12 being by-passed via duct 14 and mixed with the exhaust gases from the turbines (not shown). A fluid switch 21 has its power nozzle 20 supplied from compressor 13 via line 15 and filter 16, and the control nozzles 28, 31 are supplied from compressor 12 via line 26 and filter 27, a capacitor 29 and restrictor 30 being provided upstream of nozzle 31. During normal operation, the jet from nozzle 28 is more powerful than that from nozzle 31 and the power jet is deflected into exhaust line 22. If surge-promoting conditions arise, i. e. the output pressure from compressor 12 falls rapidly, the jet from nozzle 31 deflects the power jet into line 23, whereupon positive feedback via line 32 and nozzle 34 maintains this deflection of the power jet. The pressure rise in line 23 moves piston 25 leftwards against spring 66 and the piston unseats a disc 62 via grooved tappet 64. Fuel from a chamber housing a piston valve 39 leaks to an exhaust port 50 causing a pressure difference across the ends of valve 39 which moves rightwards against spring 56 to abut a collar 53 and cut off the main communication between fuel inlet 40 and outlet 41. A restricted passage 47 in valve 39 maintains pilot fuel flow. A valve 35 actuated by the pilots throttle lever is closed when the pilot selects reduced fuel flow and in the closed position valve 35 closes feedback line 32, separates chamber 24 from line 23 and vents chamber 24. The power jet is thus deflected back to line 22 and the fuel valve 39 opens.
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