Power plants – Combustion products used as motive fluid – Combined with regulation of power output feature
Reexamination Certificate
1999-04-16
2001-02-20
Casaregola, Louis J. (Department: 3746)
Power plants
Combustion products used as motive fluid
Combined with regulation of power output feature
C060S734000, C060S736000
Reexamination Certificate
active
06189313
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to a aircraft engine assembly. More particularly, the present invention pertains to an aircraft engine assembly minimizing the number of pipe connections which must be made during assembly, maintenance, and repair of the engine assembly.
Aircraft engine assemblies generally include a number of components such as a fuel pump, a fuel heat exchanger, and a burner or combustor. Many commercial and military aircraft include a fuel controller and an engine control actuator, in addition. It is common practice to connect the combustor, heat exchanger, fuel pump, engine control actuator and fuel controller with individual pipes or tubes. When a component, such as the fuel pump or the fuel controller, must be removed for maintenance or repair, it is necessary to detach each pipe connected to the component. Following reinstallation of the repaired component, each pipe must be reattached, and then the system must be checked for leaks, any leaking pipe connections requiring additional tightening or repair of the connection. This is a time consuming process. In particular, the number of pipe connections which must be made and then checked increases the time required, as well as the expense of engine maintenance and repair. The time requirements can result in prolonged delays in return of the aircraft to service.
The fuel pump and fuel controller are usually mounted on an engine gearbox which provides power to rotate pump. Aircraft engine fuel pumps generally have two sections, a low pressure centrifugal pump for boosting the pressure of the fuel to a low elevated pressure, and a high pressure positive displacement pump for boosting the pressure to a higher level. The boost pump pumps the fuel through a heat exchanger to heat the fuel and provides adequate pressure at the inlet of the high pressure pump to ensure proper operation. The high pressure pump is usually a gear, vane, or axial piston pump and provides the pressure needed to send the fuel to the combustor by way of the fuel controller. The high pressure pump also provides high pressure fuel to operate the engine control actuator, which, for example, might be one or more variable position inlet guide vanes.
The fuel controller receives the high pressure fuel and sends a portion of it to the combustor for burning to power the aircraft. The fuel controller sends another portion of the high pressure fuel to the engine control actuator to operate it. Excess high pressure fuel is recirculated from the fuel controller to the heat exchanger. As a consequence of all this, there a numerous pipe connections involved in removing and reinstalling either the fuel pump or the fuel controller.
SUMMARY OF THE INVENTION
The present invention is an aircraft engine assembly overcoming this problem. An aircraft engine assembly in accordance with a preferred embodiment of the present invention includes an engine which has at least one engine control and a combustion chamber or combustor with a fuel inlet, an engine control actuator for actuating the at least one engine control, a fuel heat exchanger for heating fuel, a fuel controller for controlling the flow of fuel in the aircraft engine assembly, a fuel pump, including a low pressure section for pressurizing the fuel to a low pressure and a high pressure section for pressurizing the fuel to a high pressure, an engine gearbox, and a manifold. The manifold is mounted on the engine gearbox, and the fuel pump and fuel controller are mounted on the manifold. Seal plates are positioned between the fuel pump and the manifold and between the fuel controller and the manifold. The fuel pump shaft passes through the manifold to the engine gearbox which rotates the pump shaft.
The manifold has a plurality of fuel flow paths within it. A first manifold inlet is coupled to an outlet of the fuel pump to receive the low pressure fuel from the fuel pump. This low pressure fuel passes through a first one of the manifold fuel flow paths to a first outlet which is connected to the fuel heat exchanger to provide the low pressure fuel to the heat exchanger for heating. The manifold includes a second inlet coupled to the fuel heat exchanger outlet and coupled by a second one of the fuel flow paths to a manifold second outlet which is coupled to an inlet of the fuel pump to provide the heated fuel to the fuel pump high pressure section. The manifold further includes a third inlet coupled to an outlet of the fuel pump to receive the high pressure fuel and coupled by a third one of the fuel flow paths to a manifold third outlet which is coupled to the fuel controller inlet to provide the high pressure fuel to the fuel controller. A fourth inlet of the manifold is coupled to a combustion fuel outlet of the fuel controller to receive the high pressure combustion fuel and is coupled by a fourth one of the fuel flow paths to a manifold fourth outlet which is coupled to the combustor inlet to supply the combustion fuel to the combustor. A fifth manifold inlet is coupled to a control fuel outlet of the fuel controller and is coupled by a fifth one of the fuel flow paths to a manifold fifth outlet which is coupled to the engine control actuator inlet to supply control fuel to the engine control actuator. A sixth manifold inlet is coupled to the engine control actuator outlet and is coupled to the manifold first outlet to recirculate the control fuel through the heat exchanger after actuation of the engine controls. A seventh manifold inlet is coupled to the fuel controller overflow outlet and to the manifold first outlet to recirculate any overflow fuel through the heat exchanger.
Accordingly, there are no pipe connections to the fuel pump or the fuel controller, other than the fuel pump inlet from the aircraft fuel tank. The seal plates assure fluid tight seals between the fuel pump and fuel controller and the manifold. Therefore, removal and reinstallation of the fuel pump and fuel controller can be accomplished without having to take apart or make pipe connections, and so leaking of pipe connections is not a problem.
REFERENCES:
patent: 4082324 (1978-04-01), Obrecht
patent: 4104873 (1978-08-01), Coffinberry
patent: 4245964 (1981-01-01), Rannenberg
patent: 4498693 (1985-02-01), Schindele
patent: 4646774 (1987-03-01), Hansen
patent: 4740018 (1988-04-01), Kenmochi
patent: 5090740 (1992-02-01), Creager
patent: 5159808 (1992-11-01), Kast
patent: 5203174 (1993-04-01), Meyer
patent: 5203384 (1993-04-01), Hansen
Cass Michael Andrew
Short Keith Everett
Antonelli Terry Stout & Kraus
Casaregola Louis J.
Hamilton Sundstrand Corporation
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