DE2410402

This variable displacement pump for a gas turbine fuel management system has a movable differential diaphragm assembly, one diaphragm of which pumps the fuel while another (the actuator diaphragm) effects movement of the assembly in response to forces applied thereto mechanically in response to engine operation, resiliently by spring force, and controlled fluid pressure. The displacement is varied to change the speed of the gas turbine controlled thereby by changing the pressure applied to the actuator diaphragm either through a flyweight governor driven by the gas turbine or such governor in combination with a throttle. In addition, the turbine speed may be varied by an electrically actuated valve disposed in the fuel line between the pump and the point of use. For starting purposes, a resilient force through the medium of a spring is applied to the actuator diaphragm. A combined spring and pressure actuated diaphragm is employed to maintain pressure on the fuel between the pump outlet and point of use, during the induction of fuel to the pump. In the event the gas turbine is provided with a free, or power turbine, a second flyweight governor could be utilized to change or limit the pressure applied to the actuator diaphragm and thus prevent undesired over-speed of the engine.