GB696452A - Improvements in fuel supply systems for gas turbine engines - Google Patents

Abstract

696,452. Gas turbine plant. HOBSON, Ltd., H. M., and TYLER, S. R. April 25, 1952 [May 31, 1951], No. 12886/51. Class 110(iii) [Also in Group XXIX] In a fuel system for aircraft gas-turbine engines in which a spill valve 3 is actuated by a servo mechanism 5 governed by a flow control unit (not shown) for maintaining a required rate of flow of fuel selectable by the pilot but varied in response to changes in ambient atmospheric pressure, and by a maximum speed governor, one side of the servo mechanism being exposed to a high pressure fluid and the other side having a restricted connection 7 with the high pressure side and connections 9, 10 to the flow control unit and a governor operated valve 11, .respectively, the high pressure side of the servo mechanism is connected to the spill line 4 upstream of a pressurizing valve 18. The arrangement eliminates " speed run-up " which occurs if the high-pressure side of the servo mechanism is connected to the delivery side of the fuel pump 1, when reduction of pressure in the delivery conduit 2 due to decreased fuel consumption at altitude is transmitted to the governor valve 11 resulting in a smaller force acting on the valve in opposition to the force which is responsive to speed, so that the speed at which the valve opens to bleed fuel from the servo mechanism to increase the spill opening increases with altitude. The valve 11 is operated by a spring-loaded diaphragm 13 (or piston) which is subject to the pressure difference across an engine-driven impeller 15. Alternatively, the valve 11 may be operated by a mechanical governor. Instead of the spring-loaded servo piston 5, differential pistons may be employed.