Fuel float valve

Abstract

A fuel system includes a fuel tank that has a wall with an opening. A fuel float valve includes a float and a seal plate that are arranged on opposing ends of a beam. A support carries a connection of the beam. The beam is configured to translate along the support at the connection in response to a changing fuel level. The fuel float valve is movable between first and second positions in which the seal plate is respectively unsealed and sealed relative to the opening. The seal plate is movable relative to the opening in the second position.

Claims

1. A fuel system comprising: a fuel tank having a wall with an opening; a fuel float valve including a float and a seal plate on opposing free ends of a beam, and a support carrying a connection of the beam, the beam is configured to translate along the support at the connection in response to a changing fuel level, and wherein the float and the seal plate are configured to translate linearly with the beam, the fuel float valve is movable between first and second positions in which the seal plate is respectively arranged in unsealed and sealed positions relative to the opening; wherein the seal plate is movable relative to the opening in the second position; wherein the wall separates first and second sides, the first tank including a cavity and the first side arranged in the cavity, the plate on the second side outside the cavity; a surge tank fluidly connected to the fuel tank by a vent line, the seal plate blocking flow between the fuel tank and the surge tank in the sealed position; and a nitrogen gas system fluidly connected to the fuel tank at a first side of the opening, the surge tank at a second side of the opening opposite the first side.

2. The fuel system according to claim 1, wherein the support provides a linear path.

3. The fuel system according to claim 1, wherein the float is arranged in the cavity.

4. The fuel system according to claim 3, wherein the float and the seal plate are arranged on opposing sides of the connection on the beam.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

(2) FIG. 1 is a schematic view of a fuel system.

(3) FIG. 2A is a schematic view of an example fuel float valve in an unsealed position at a first fuel level.

(4) FIG. 2B is a schematic view of the fuel float valve illustrated in FIG. 2A in a sealed position at a second fuel level that is greater than the first level.

(5) FIG. 3A is a schematic view of a plate illustrated in FIG. 2B in a closed position.

(6) FIG. 3B is an elevational view of the plate illustrated in FIG. 3A.

(7) FIG. 3C is a schematic view of the plate illustrated in FIG. 3A in an open position.

(8) FIG. 4A is a schematic view of another fuel float valve in an unsealed position at a first fuel level.

(9) FIG. 4B is a schematic view of the fuel float valve shown in FIG. 4A in the sealed position at a second fuel level that is greater than the first level.

DETAILED DESCRIPTION

(10) A fuel system 10 is schematically illustrated in FIG. 1. The system 10 is typical of an aircraft fuel system, and includes a center tank 12 fluidly connected to lateral tanks 14 by fuel lines 16. The fuel system 10 supplies fuel F to a component 18, such as a gas turbine engine.

(11) A surge tank 20 is fluidly connected to at least one of the tanks, such as the center tank 12, by a vent line 22. A nitrogen generation system 26 is fluidly connected to the center tank 12 to provide nitrogen gas to the fuel system 10 to fill the gaseous cavities within the tanks with inert gas, such as cavity 28 in the center tank 12.

(12) A fuel float valve 24 selectively regulates the flow of gases from the cavity 28 to the surge tank 20. As the level of fuel F within the center tank 12 rises, the fuel flow valve 24 will close to block fuel flow from the center tank 12 to the surge tank 20, thus preventing fuel from pouring into the surge tank 20.

(13) It is desirable to prevent the fuel float valve from becoming stuck in a closed or sealed position even after the fuel level decreases. A stuck valve can prevent proper venting of the center tank 12 to the surge tank 20. To this end, the fuel float valve 24 includes a feature for insuring that it can still vent even if it becomes stuck.

(14) The fuel float valve 24′ includes a beam 32 having a float 34 and a plate 40 at opposing ends, as illustrated in FIGS. 2A-2B. The beam 32 pivots about a fulcrum 30. The plate 40 selectively blocks an opening 38 in a wall 36 of the center tank 12. The opening 38 fluidly connects the center tank 12 to the surge tank 20. Flow through the opening 38 is blocked in a closed position with the plate 40 sealed against the wall 36.

(15) Referring to FIGS. 3A-3C, the plate 40 includes first and second portions 42, 44 that are moveable relative to one another. The first portion 42 includes a central support 48 having a fastener 50 that secures the plate 40 to the beam 32. Legs 52 extend radially from the central support 48 and are interconnected to an annular portion 54, which provides a sealing surface configured to seal against the wall 36. Spaces 56 are provided between the central support 48, legs 52 and annular portion 54. The second portion 44 blocks the spaces 56 in a closed position (FIG. 3A).

(16) A biasing member 46, such as a spring, urges the second portion 44 to the closed position relative to the first portion 42. In response to a predetermined pressure differential across the plate 40, the force of the biasing spring is overcome permitting the second portion 44 to move out of engagement with the first portion 42, creating a gap 58. The gap 58 permits fluid flow through the plate 40 even with the first portion 42 sealed against the wall 36. Thus, the second portion 44 acts as a relief valve in the plate 40 should become stuck closed.

(17) Another fuel float valve 124 is illustrated in FIG. 4A-4B. A guide or support 60 is mounted within the cavity 128 of the fuel tank 112. The fuel float valve 124 includes a beam 132 that supports a float 134 and a plate 140 at opposing ends. The beam 132 is supported for translation by the support 60 at a connection 66. In one example, the support 60 provides a linear path L along which the fuel float valve 124 moves vertically in response to changes in the fuel level, as illustrated in the figures. The wall 136 defines first and second sides 62, 64. The first side 62 is provided within the cavity 128. The plate 140 is arranged on the second side 64, which is unpressurized, preventing an increased pressure from the nitrogen generation system from holding the plate 140 in a closed position. Rising pressure within the cavity 128 will force the plate out of engagement with the wall 136, and unobstruct the opening 138.

(18) Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content.