# US 7,607,285 B2 · Four mode thermal recirculation throttle valve

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- Number: US 7,607,285 B2
- Document ID: US7607285B2
- Status: Granted
- Kind: B2
- Application number: 10/740,651
- Filed: 2003-12-18
- Published: 2005-02-03
- Granted: 2009-10-27
- Earliest claimed: 2003-08-01
- Assignees: Honeywell International Inc.
- Inventors: Paul W. Futa, Jr.; David J. Hauck; Gregory E. Kline; Steven A. Lewis; George S. Wieger
- Web page: https://patentgrep.com/patent/US7607285B2

## CPC

- F02C 7/232: Fuel valves {(control of fuel supply by means of fuel metering valves F02C9/263)}; Draining valves or systems (valves in general F16K)
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A thermal recirculation throttle valve (1) for an aircraft fuel system includes a housing (11) having a throttling valve chamber; a cover (5) operatively engaging a first side of the housing (11); a power piston (6) within a power piston sleeve (7), the power piston (6) having a first (21) and second face (22) for control pressure to act upon, the power piston (6) and power piston sleeve (7) operatively engaged with the housing (11) within the throttling valve chamber; a Linear Variable Differential Transformer (15) for measuring a linear position of the power piston (6) within the housing (11); a throttling valve (8) within a throttling valve sleeve (9), the throttling valve (8) operatively engaged with the power piston (60) to transfer the linear movement of the piston (6) between a fully extended and a fully retracted operating position; and a flow deflector (10) engaged with the throttling valve (8) for protecting the housing (11) from flow erosion from fuel exiting flow windows (37). The throttling valve (8) includes a pair of fail-safe operating positions, a fully open operating position, a low leakage shutoff operating position, and a variety of variable flow operating positions between the shutoff and fully open operating positions.

## Claims

### Claim 1

A thermal recirculation throttle valve for an aircraft fuel system, the thermal recirculation throttle valve comprising: a housing having a throttling valve chamber, an inlet, a first outlet, and a second outlet; a power piston disposed within the housing for translational movement therein; and a throttling valve mounted to the power piston and configured to move therewith between: (i) a fuel shut-off position wherein the throttling valve substantially blocks fuel flow from the inlet to the first outlet and substantially permits fuel flow from the throttling valve chamber to the second outlet, (ii) a fully open operating position wherein the throttling valve substantially permits fuel flow from the inlet to the first outlet and substantially blocks fuel flow from the throttling valve chamber to the second outlet, (iii) a failsafe extended position wherein the throttling valve permits a predetermined flow from the inlet to the first outlet, and (iv) a failsafe retracted position wherein the throttling valve permits a predetermined flow from the inlet to the first outlet;
wherein the fuel shut-off position resides between the failsafe extended position and the fully open operating position, and wherein the fully open operating position resides between the failsafe retracted position and fuel shut-off position;
and wherein the thermal recirculation throttle valve further comprises means for preventing the throttling valve from extending beyond the failsafe extended position, and means for preventing the throttling valve from retracting beyond the failsafe retracted position.

### Claim 2 (depends on 1)

The thermal recirculation throttle valve according to claim 1, wherein the fully open operating position of the throttling valve permits a maximum flow of fuel through the first outlet.

### Claim 3 (depends on 2)

The thermal recirculation throttle valve according to claim 2, wherein the maximum flow of fuel is approximately 10,500 lbs/hour of aircraft fuel.

### Claim 4 (depends on 1)

The thermal recirculation throttle valve according to claim 1, further comprising an inlet flow window control land and an outlet flow window control land being formed on the throttling valve, the control lands operatively controlling a flow of fuel from the inlet to the first outlet and to the second outlet.

### Claim 5

A main fuel throttle valve assembly for an aircraft fuel system including a fuel storage tank and a main pump, the main fuel throttle valve assembly comprising:
a main fuel throttle valve configured to receive fuel from the main pump and drawn from the fuel storage tank;
a thermal recirculation throttle valve, comprising:
a housing having a throttling valve chamber, an inlet configured to be fluidly coupled to an outlet of the main pump, a first outlet configured to be fluidly coupled to the inlet of the main pump, and a second outlet configured to be fluidly coupled to an inlet of the fuel storage tank;
a power piston disposed within the housing for translational movement therein;
a throttling valve mounted to the piston and configured to move therewith between: (i) a fuel shut-off position wherein the throttling valve substantially blocks fuel flow from the inlet to the first outlet and substantially permits fuel flow from the throttling valve chamber to the second outlet, (ii) a fully open operating position wherein the throttling valve substantially permits fuel flow from the inlet to the first outlet and substantially blocks fuel flow from the throttling valve chamber to the second outlet, (iii) a failsafe extended position wherein the throttling valve permits a predetermined flow from the inlet to the first outlet, and (iv) a failsafe retracted position wherein the throttling valve permits a predetermined restricted flow from the inlet to the first outlet;
a first structural element within the housing and configured to engage at least one of the power piston and the throttling valve to prevent the throttling valve from extending beyond the failsafe extended position; and a second structural element within the housing and configured to engage at least one of the power piston and the throttling valve to prevent the throttling valve from retracting beyond the failsafe retracted position;
wherein the fuel shut-off position resides between the fully open operating position and the failsafe extended position, and wherein the fully open operating position resides between the fuel shut-off position and the failsafe retracted position.

### Claim 6 (depends on 5)

The main fuel throttle valve assembly according to claim 5, wherein the fully open operating position of the throttling valve permits a maximum flow of fuel through the inlet.

### Claim 7 (depends on 6)

The main fuel throttle valve assembly according to claim 6, wherein the maximum flow of fuel is approximately 10,500 lbs/hour of aircraft fuel.

### Claim 8 (depends on 5)

The main fuel throttle valve assembly according to claim 5, further comprising an inlet flow window control land and an outlet flow window control land being formed on the throttling valve, the control lands operatively controlling a flow of fuel from the inlet to the first outlet and to the second outlet.

### Claim 9

A fuel system for an aircraft including a plurality of gas generator nozzles, the fuel system comprising: a fuel storage tank;
a main fuel throttle valve configured to be fluidly coupled to the plurality of gas generator nozzles and to supply metered fuel thereto;
a main fuel pump fluidly coupled between the main fuel throttle valve and the fuel storage tank, the main fuel pump configured to supply the main fuel throttle valve with pressurized fuel from the fuel storage tank; and
a thermal recirculation throttle valve, comprising:
a housing having a throttling valve chamber, an inlet fluidly coupled to an outlet of the main pump, a first outlet fluidly coupled to the inlet of the main pump, and a second outlet fluidly coupled to an inlet of the fuel storage tank;
a power piston disposed within said housing for translational movement therein; and
a throttling valve mounted to the piston and configured to move therewith between: (i) a fuel shut-off position wherein the throttling valve substantially blocks fuel flow from the inlet to the first outlet and substantially permits fuel flow from the throttling valve chamber to the second outlet, (ii) a fully open operating position wherein the throttling valve substantially permits fuel flow from the inlet to the first outlet and substantially blocks fuel flow from the throttling valve chamber to the second outlet, (iii) a failsafe extended position wherein the throttling valve permits a predetermined flow from the inlet to the first outlet, and (iv) a failsafe retracted position wherein the throttling valve permits a predetermined flow from the inlet to the first outlet; wherein the fuel shut-off position and the fully open operating position reside intermediate the failsafe extended position and the failsafe retracted position; and wherein the thermal recirculation throttle valve further comprises means for preventing the throttling valve from extending beyond the failsafe extended position, and means for preventing the throttling valve from retracting beyond the failsafe retracted position.

### Claim 10 (depends on 9)

The fuel system according to claim 9, wherein the thermal recirculation throttle valve includes a low pressure vent to a low pressure side of the fuel system.

### Claim 11 (depends on 10)

The fuel system according to claim 10 further comprising a booster pump fluidly coupled between the fuel storage tank and the main fuel pump, the low pressure side of the fuel system comprising an outlet of the booster pump.

### Claim 12 (depends on 9)

The fuel system according to claim 9 wherein the aircraft further includes an electronic control and wherein the fuel system further comprises:
a servo valve hydraulically coupled to the thermal recirculation throttle valve and operatively coupled to the electronic control, the servo valve cooperating with the electronic control to selectively move the power piston between the fuel shut-off position and the fully open position to apportion fuel between the fuel storage tank and the main pump and thereby regulate the temperature of the fuel conducted by the fuel system.

### Claim 13 (depends on 12)

The fuel system according to claim 12, further comprising:
a housing cover fixedly coupled to the housing;
a throttling valve sleeve fixedly mounted within the housing and including first and second windows therethrough aligning with the inlet and the first outlet, respectively; and
a power piston sleeve fixedly mounted within the housing between the housing cover and the throttling valve sleeve.

### Claim 14 (depends on 13)

The fuel system according to claim 13, wherein the power piston includes first and second opposing radial faces that cooperate with the power piston sleeve and the housing cover to define first and second chambers within the throttling valve sleeve, the servo valve fluidly coupled to the first and second chambers and configured to adjust the pressure therein to control the translational position of the piston.