Abstract: A fuel system includes a first fuel line carrying fuel at a first line pressure (P22), a second fuel line carrying fuel at a second line pressure (PFNC) greater than the first line pressure (P22), at least one pressure regulating section 102 having an input 101 connected to the second fuel line and at least one output (103), a first pressure regulator (120) connected to the input and a second pressure regulator (130) connected between the first pressure regulator (120) and the at least one output (103), and a controller (160) controlling the position of the first and second pressure regulators (120, 130) to produce at the output (103) one of a predetermined number of output pressures relative to the first line pressure (P22).

Abstract: A controlled piston (20, 62, 102) having a first end (24, 64, 104) mounted in a controlled piston sleeve (22) and a spool (16) movably mounted in a spool sleeve (18), a first fluid passage (40, 66, 108) from the spool (16) to the controlled piston first end (24, 64, 104), the position of the spool (16) affecting a position of the controlled piston (20, 62, 102), an FFV (42, 68, 110) in an FFV sleeve (44, 70, 112) in the first fluid passage (40, 66, 108) having a first end section (46, 74, 116), a second end section (48, 78, 120) and a central section (50, 82, 126) having a third diameter less than the diameters of the first and second sections, the FFV (42, 68, 110) being shiftable between a first position blocking the first fluid passage (40, 66, 108) and a second position allowing fluid flow past the central section (50, 82, 126) to the controlled piston (20, 62, 102), and a second fluid passage (56, 88, 134) from the spool (16) to the FFV first end section (46, 74, 116).

Abstract: The present invention discloses a relatively simple system and method to reduce fuel system pumping by automatically turning on and off servo flow to various non-needed devices or “start lockout” servos during engine start. The invention takes advantage of a fuel pressure rise provided by the fuel pump during the period from engine start until the pump speed is greater than windmill. This pressure rise is used to move a pressure activated piston in a servo shutoff valve from a normally closed position to an open position, which at higher pressures allow servo flow to the “start lockout” servos through the servo lockout valve. When the pressure is reduce, the piston return to a normally closed position due to a biasing spring closing the servo lockout valve. This opening and closing of the servo lockout valve occurs automatically with no other external input.

Abstract: A fuel flow dividing ecology valve conveys fuel from a fuel source to at least a secondary gas turbine engine intake manifold during engine operation and withdraws fuel therefrom upon cessation of engine operation. The valve includes a flow dividing valve portion having an inlet coupled to the fuel source and an outlet coupled to the secondary manifold. The valve also includes an ecology valve portion controlled by the fuel pressure differential between the fuel source and the flow restricting inlet. The ecology valve portion includes a housing with a movable piston disposed therein. The piston defines, in conjunction with the housing, a variable volume chamber for withdrawing fuel from the engine intake manifolds. When the engine is de-energized, the piston moves from a first position toward a second position thereby purging the manifolds of fuel.

Abstract: A purge air and fuel flow divider module (15) independently directs fuel flow to a plurality of manifolds (25, 27 and 29) and independently purges fuel from these manifolds with air when they are not flowing fuel. A secondary manifold (29) is filled with fuel before flowing metered burn flow to it and fuel flow is apportioned between a primary manifold (27) and the secondary manifold (29) during secondary manifold metered burn flow. Three manifolds are disclosed, a primary manifold (27), a secondary manifold (29) and a start or pilot manifold (25), each containing fuel nozzles (31, 33). A manifold main housing (61) contains a purge valve (41) and two three-way solenoids (37, 39) controlling respectively a secondary transfer valve (43) and a pilot nozzle transfer valve (45). Depending on the requirements, the solenoids position the valves to either provide manifold fill fuel, burn flow fuel or purge air to their respective manifolds.

Abstract: A fuel flow dividing ecology valve conveys fuel from a fuel source to at least a secondary gas turbine engine intake manifold during engine operation and withdraws fuel therefrom upon cessation of engine operation. The valve includes a flow dividing valve portion having an inlet coupled to the fuel source and an outlet coupled to the secondary manifold. The valve also includes an ecology valve portion controlled by the fuel pressure differential between the fuel source and the flow restricting inlet. The ecology valve portion includes a housing with a movable piston disposed therein. The piston defines, in conjunction with the housing, a variable volume chamber for withdrawing fuel from the engine intake manifolds. When the engine is de-energized, the piston moves from a first position toward a second position thereby purging the manifolds of fuel.

Abstract: A fuel control system for supplying metered quantities of fuel from a fuel supply (11), through a fuel pump (13), a metering valve (15) and a pressurizing valve (17) to a plurality of engine fuel manifolds (31a, 31b, 33) includes an ecology valve (43) for withdrawing fuel from the engine fuel manifolds (31a, 31b, 33) during cessation of engine operation and for returning fuel to the engine fuel manifolds (31a, 31b, 33) to be burned during normal engine operation. The ecology valve (43) includes a valve housing (44) having a plurality of ecology ports (50, 52, 54) adapted to be coupled to corresponding ones of the engine fuel manifolds (31a, 31b, 33) and a control port (46) adapted to be connected to a corresponding control port (45) of the fuel pressurizing valve (17).

Abstract: A fuel control system for supplying metered quantities of fuel from a fuel supply (11), through a fuel pump (13), a metering valve (15) and a pressurizing valve (17) to a plurality of engine fuel manifolds (31a, 31b, 33) includes an ecology valve (43) for withdrawing fuel from the engine fuel manifolds (31a, 31b, 33) during cessation of engine operation and for returning fuel to the engine fuel manifolds (31a, 31b, 33) to be burned during normal engine operation. The ecology valve (43) includes a valve housing (44) having a plurality of ecology ports (50, 52, 54) adapted to be coupled to corresponding ones of the engine fuel manifolds (31a, 31b, 33) and a control port (46) adapted to be connected to a corresponding control port (45) of the fuel pressurizing valve (17).

Abstract: A fuel control system for supplying metered quantities of fuel from a fuel supply (11), through a fuel pump (13), a metering valve (15) and a pressurizing valve (17) to a plurality of engine fuel manifolds (31a, 31b, 33) includes an ecology valve (43) for withdrawing fuel from the engine fuel manifolds (31a, 31b, 33) during cessation of engine operation and for returning fuel to the engine fuel manifolds (31a, 31b, 33) to be burned during normal engine operation. The ecology valve (43) includes a valve housing (44) having a plurality of ecology ports (50, 52, 54) adapted to be coupled to corresponding ones of the engine fuel manifolds (31a, 31b, 33) and a control port (46) adapted to be connected to a corresponding control port (45) of the fuel pressurizing valve (17).

Abstract: A fuel control system for supplying metered quantities of fuel from a fuel supply (11), through a fuel pump (13), a metering valve (15) and a pressurizing valve (17) to a plurality of engine fuel manifolds (31a, 31b, 33) includes an ecology valve (43) for withdrawing fuel from the engine fuel manifolds (31a, 31b, 33) during cessation of engine operation and for returning fuel to the engine fuel manifolds (31a, 31b, 33) to be burned during normal engine operation. The ecology valve (43) includes a valve housing (44) having a plurality of ecology ports (50, 52, 54) adapted to be coupled to corresponding ones of the engine fuel manifolds (31a, 31b, 33) and a control port (46) adapted to be connected to a corresponding control port (45) of the fuel pressurizing valve (17).

Abstract: An unbalance compensated bypass valve (14, 21, 23) for a gas turbine engine fuel supply system is responsive to the fuel pressure differential across a fuel metering valve (15) to open and close a bypass orifice (37, 39, 41; 89, 91, 93; 99, 101, 103). The bypass valve (14, 21, 23) selectively supplies high fuel pressure to a compensating cavity (45, 95, 120) providing a counterbalancing force against an annular area (47, 97, 124) of the bypass valve piston (34, 81, 83, 111, 112) to compensate for increased restorative forces of a helical reference spring (57, 112, 125) as that spring is collapsed as well as to compensate for other unbalance conditions within the valve (14, 21, 23). The compensating cavity may include a variable orifice inlet (37, 39, 41), (99, 101, 103), or (89, 91, 93) and a variable orifice outlet (105, 107, 109) or the inlet orifice may be variable while the outlet orifice (43, 96, 99) is fixed.

Abstract: A fuel control system for supplying metered quantities of fuel from a fuel supply (11), through a fuel pump (13), a metering valve (15) and a pressurizing valve (17) to a plurality of engine fuel manifolds (31a, 31b, 33) includes an ecology valve (43) for withdrawing fuel from the engine fuel manifolds (31a, 31b, 33) during cessation of engine operation and for returning fuel to the engine fuel manifolds (31a, 31b, 33) to be burned during normal engine operation. The ecology valve (43) includes a valve housing (44) having a plurality of ecology ports (50, 52, 54) adapted to be coupled to corresponding ones of the engine fuel manifolds (31a, 31b, 33) and a control port (46) adapted to be connected to a corresponding control port (45) of the fuel pressurizing valve (17).

Abstract: A fuel control system for supplying metered quantities of fuel from a fuel supply (11), through a boost pump (13), a filter (21), a high pressure fuel pump (14), a metering valve (15) and a pressurizing valve (17) to an engine fuel manifold (19) includes an ecology valve (43) which provides a fuel flow path (41, 42, 71, 46, 18) between the pressurizing valve (17) and the engine fuel manifold. The status of the ecology valve (43) is solely determined by the status of the pressurizing valve (17). The ecology valve (43) includes a housing (93, 95, 97) with a piston (61) disposed therein which is reciprocable between two extreme positions. The piston (61) defines, in conjunction with the housing, a variable volume chamber (55) for withdrawing a one piston stroke volume of fuel from the engine fuel manifold when the engine is de-energized and the piston (61) moves from one extreme position to the other thereby purging the fuel manifold of fuel.

Abstract: An unbalance compensated bypass valve (23) for a gas turbine engine fuel supply system is responsive to the fuel pressure differential across a fuel metering valve (15) to open and close a bypass orifice (37, 39, 41). The bypass valve (23) selectively supplies high fuel pressure to providing a counterbalancing force against an annular area (47) of the bypass valve piston 34 to compensate for increased restorative forces of a helical reference spring (57) as that spring is compressed as well as to compensate for other unbalance conditions within the valve (23). The piston (34) includes additional sidewall openings (69, 70, 71) which function during a "shut-off" condition to divert all fuel flow from an inlet of the metering valve (15) back to a fuel pump (13) inlet. The piston (34) also includes further sidewall openings (73, 75) which provide a controlled fuel leakage from a bypass valve inlet line (25) to the bypass valve pressure sensing inlet (29).

Abstract: A combination pressurizing valve (27) and fuel flow divider for a gas turbine is operable in three different fuel distribution modes utilizing three windows which are successively opened to control the flow distribution to the engine atomizing or start-up nozzles (23) and engine air blast or running nozzles (25) respectively by way of two fixed orifices (51, 55) in a way that satisfies the start-up flow distribution favoring the atomizing nozzles (23) as well as the need for balanced flow distribution between the different types of engine nozzles after a successful start. The first window position corresponds to an engine ignition mode and includes a range of intermediate valve spool (33, 133) positions where one outlet port (57) is open and the other outlet port (67) receives a restricted flow of fuel.

Abstract: A mechanical governor for use in a fuel management system having a fuel metering loop responsive to an electronic computer for supplying fuel to a combustion chamber of a turbine. The mechanical governor includes a cylindrical spinning spool valve assembly located in a bore which is responsive to an operational force derived from the rotation of the turbine. In a first mode of operation, communication of control pressure P.sub.c to an integrator valve assembly is inhibited by a first spring associated with the spool valve assembly while in a second mode of operation communication of an operational fluid pressure P.sub.x derived from the control pressure P.sub.c is communicated to the integrator valve assembly after an operational force corresponding to the rotation overcomes the first spring. In the first and second modes of operation, fuel is supplied to the combustion chamber as a function of a pressure differential across the fuel metering loop.

Abstract: A dual signal head sensor, which is a fluid pressure differential sensitive control valve, has a diaphragm responsive to changes in fluid pressure on opposite sides thereof and a ported sleeve having a spool valve axially movable in response to diaphragm motion. The head sensor monitors a fluid pressure differential and provides fluidic control signals in response to sensed variations in the pressure differential. A pair of chambers separated by the diaphragm receive variously pressurized fluids and thereby impress across the diaphragm the pressure differential being monitored. The head sensor has a ported sleeve with a high pressure inlet, a low pressure return, two control connections or dual signal outputs, and a movable spool having 4 lands.

Abstract: A seal for preventing leakage of pressurized fluid along a flow path along an engagement plane between a first and second members. The seal has a cylindrical body with a first elastomeric ring located on an end and a second elastomeric ring located on a peripheral surface of the cylindrical body. The cylindrical body is located in a passage in the second member. A spring urges the first elastomeric ring into engagement with a face on the first member when the first and second members are joined together. Pressurized fluid which flows from a passage in the first member into the second passage in the second member acts on the cylindrical body to further urge the end into engagement with the first member to prevent fluid leakage along the engagement plane there between.

Abstract: A filter arrangement (26) for a fuel system (10) having a cartridge (92) located in a bore (48) of a housing (42) for sequentially interruption flow communication from the bore (48) to a regulator (14) through an outlet port (44) and to the bore (48) through an inlet port (46) from a source (16) of fuel prior to the removal of the cartridge (94) from a housing (42). The housing (42) has a vent port (52) and a drain port (54) which are opened to allow fuel in the bore (48) to flow to a storage container (56) once the outlet (44) and inlet (46) ports are closed so that fuel is not lost from the fuel system (10) on the removal of the cartridge (94) from the bore (48).

Abstract: A pressuring valve having a housing with a bore therein for retaining concentric first and second pistons within a sleeve having an end wall with an entrance port connected to a first conduit. A spring within the bore urges a first face on the first piston toward a first seat which surrounds the entrance port and a second face on the second piston toward a second seat surrounding an annular opening in the first piston. The fluid pressure in the first conduit acts on the first face to overcome the spring and move the first piston away from the entrance port to allow fluid to flow to an exit port in the housing. This type flow continues until such time that the first piston fails to move when the fluid pressure thereafter acts on the second face to move the second piston and allow the fluid to flow to the exit by way of the annular opening and a plurality of axial opening in the first piston to maintain the fluid pressure in the first conduit substantially constant.