| 摘要 |
<p>1,140,181. Compressors. UNITED AIRCRAFT CORP. June 5, 1967 [June 6, 1966], No. 25782/67. Heading F1C. An air-conditioning system is supplied from the compressor 1, Fig. 1, of an aircraft gas turbine engine via a duct 2 containing a control valve 8. If the pressure downstream of the valve 8 exceeds, say, 135 lb./sq. inch., it acts via a line 17 to move a diaphragm 16 against the action of a spring 18 to open a valve 21 which vents a servo-pressure supply line 54 to atmosphere. The resultant decrease in servo-pressure causes the actuator 10 of the valve 8 to move the valve 8 towards the closed position to reduce the downstream pressure. If the diaphragm 16 breaks or is punctured, the valve 21 will not be opened when the downstream pressure exceeds 135 lb. /sq inch. However, if the downstream pressure reaches 170 lb. /sq. inch, the pressure acts via lines 17, 36, 40 to move a diaphragm 24 against the action of a spring 26 to open an emergency valve 28 to vent the servo-pressure line 54 to atmosphere, thereby preventing further rise of the downstream pressure. In addition, a cam 56 attached to the diaphragm 24 opens a valve 42 to admit the pressure upstream of the control valve 8 via a line 39 to the space 34 above the diaphragm 24. Consequently, the diaphragm 24 is acted on by the upstream pressure instead of the downstream pressure and the valve 28 therefore remains open until the upstream pressure falls below 170 lb. /sq. inch. An orifice 43 restricts the flow from the space 34 to the line 17 when the valve 42 is open. Orifices 45, 46 and plenum chamber 44 reduce the possibility of the emergency valves 28, 42, being operated by rapid changes of upstream pressure. The loss of air-conditioning occurring while the valve 28 remains open warns the pilot of a failure of the primary control 16, 21. He can restore the air-conditioning by reducing the engine speed so as to reduce the upstream pressure. In a modification, Fig, 2, the diaphragm 24 operates a valve 57 to connect the line 39 to the space 34.</p> |
