Gas turbine engine fuel system

Claim 1

IN A GAS TURBINE ENGINE HAVING A COMPRESSOR AND A CENTRIFUGAL FUEL PUMP, A FUEL SYSTEM COMPRISING A THROTTLE VALVE BODY HAVING A PORT THEREIN, AN OBTURATING MEMBER WHICH IS AXIALLY MOVABLE WITHIN THE THROTTLE VALVE BODY SO AS TO THROTTLE FUEL FLOW FROM SAID PUMP THROUGH SAID PORT, A VALVE MEMBER, THE VALVE MEMBER AND THE OBTURATING MEMBER BEING MOUNTED CONCENTRICALLY WITHIN EACH OTHER, MEANS FOR EFFECTING AXIAL POSITIONING OF THE VALVE MEMBER IN ACCORDANCE WITH THE VALUE OF A FIRST ENGINE VARIABLE DETERMINABLE FROM THE COMPRESSOR, MEANS CONTROLLED BY SAID VALVE MEMBER FOR ADJUSTING THE VALUE OF A FUEL FLUID PRESSURE UPSTREAM OF SAID PORT AND APPLIED TO ONE SIDE OF THE OBTURATING MEMBER, AND MEANS FOR APPLYING TO THE OTHER SIDE OF THE OBTURATING MEMBER A SECOND FUEL FLUID PRESSURE WHICH VARIES IN ACCORDANCE WITH THE VALUE OF A SECOND ENGINE VARIABLE DETERMINABLE BY PUMP OUTPUT PRESSURE, THE AXIAL POSITION OF THE OBTURATING MEMBER DEPENDING SOLELY ON THE FLUID FORCES ACTING ON IT.