FIELD OF THE INVENTION

The present invention relates to an aircraft fuel system ball valve.

BACKGROUND

Due to their relative simplicity and reliability, ball valves are commonly used as isolation valves in fluid systems. Ball valves advantageously provide positive shutoff with minimal pressure drop and flow turbulence across the valve. In aircraft fuel systems fuel valves may for example be used in applications such as refuelling/defueling, tank-to-tank transfer and emergency fuel jettison or fuel dumping.

A ball valve is typically a quarter turn valve which includes a "ball" (which may be generally spherical but is not specifically limited to such a shape) having a bore or port extending therethrough. In most isolation valves the port is a simple axial passage. The ball is pivotally located within the valve body and may be rotated between an "open" position in which the bore is aligned with the flow line of the valve and a "closed" position in which the ball is rotated 90- degrees. In the closed position the bore of the ball is generally perpendicular to the flow line of the valve and the sidewalls of the ball block the flow line to close off the flow.

A typical aircraft fuel system ball valve 10 is shown in Figure 1. The valve comprises a ball member 12 positioned between first and second end retainers 13, 14 which provide conduit sections extending out of the valve body. The retainers may for example be adapted to connect to a pipe end. A ball housing 15 surrounds and supports the ball member 12. The end retainers are connected to the ball housing 15 either side of the ball member 12 (which is therefore captive within the housing 15). A mounting flange 16 supports the valve in use (and in the illustrated valve is of a generally cantilever type arrangement extending away from the ball housing 15). A drive assembly 18 is provided for rotating the ball member 12 in use. The drive assembly includes a shaft 17 which extends along (and through) the mounting flange 16. The end of the drive assembly distal to the ball member 12 is adapted to allow operation of the valve (for example it may receive a handle or a gear which can be turned in use to rotate the ball member 12).

It is would be beneficial to provide an improved aircraft fuel system ball valve having a simplified and/or lightweight construction.

SUMMARY OF INVENTION According to a first aspect of the invention, there is provided an aircraft fuel system ball valve, the valve comprising: an integrated valve housing defining: a support member portion, a ball housing portion and a first conduit portion on a first side of the ball housing portion, and an aperture on a second side of the ball housing, the second side being generally opposite to the first side; a ball member rotatably received within the ball housing; and a second conduit member disposed on an opposing side of the ball member from the first conduit section; and wherein the second conduit member and aperture of the integrated valve housing have complimentary engagement features such that the second conduit member may be removably attached to the integrated valve housing.

When the second conduit member is attached to the housing the ball member may be captive between the first conduit portion and second conduit member. Thus, the ball valve may provide a flow path through the first conduit, second conduit and ball member in an assembled configuration. Thus, in embodiments of the invention the assembly of the ball valve is greatly simplified. Embodiments of the invention may remove the need for separate fastener elements such as screws between components of the valve assembly and may therefore significantly reduce the overall part count.

The second conduit member may include an interface portion having an external diameter which may be received within the aperture of the integrated valve housing. The interface portion may be arranged to sealingly engage an inner surface of the aperture. A seal member may be provided on one of the inner surface of the aperture or the outer surface of the interface portion.

The ball member may be positioned within the integral valve housing and may for example be rotatably retained therein by a spindle. For example, the ball member may be retained by a spindle member on one side and a drive shaft on a radially opposed side of the ball member. The spindle member and drive shaft may be coaxial. The drive shaft may extend through a drive passage defined in the integrated valve housing, for example a drive passage extending through the support member portion. The distal end of the drive shaft may be provided with an interface for connection to a drive assembly.

The integrated valve housing may be formed of a moulded material. For example the integrated valve housing may be formed from a plastic material, such as polyether ether ketone (PEEK). The plastic material may be carbon reinforced.

The complimentary engagement features of the integrated valve housing may be provided on the ball housing. For example the complimentary features may be arranged around the periphery of the aperture. The corresponding complimentary features of the second conduit member may be positioned around the periphery of a first end of the conduit member (generally the end proximal to the ball when assembled).

In some embodiments the complimentary engagement may comprise complimentary snap fit features. The complimentary snap fit features may comprise resilient features which may be deflected during assembly so as to pass over one another and then resiliently engage the second conduit member in the assembled configuration. For example, the snap fit features may comprise an external projection which is received into a corresponding internal recess. The outer surface of the second conduit member may be formed with at least one outwardly extending projection for engaging a corresponding recess on an inner surface of the aperture. The projection and/or recess may be at least partially circumferentially extending. The projection and/or recess may be annular and extend around the entire periphery of the aperture and conduit member. The projection and/or recess may be interrupted circumferentially (for example to provide a snap fit arrangement which also rotationally orients the components).

The ball valve of the invention may also be arranged such that disassembly is possible for example for maintenance or replacement of components. For example, the integrated valve housing may include at least one aperture aligned with the snap fit complimentary features such that the snap fit features may be deflected out of engagement. For example a plurality of apertures may be provided at circumferentially spaced apart positions to allow the snap fit complimentary features to be disengaged around substantially the entire circumference of the conduit during disassembly. A dedicated tool may be provided with aligned members for disengaging the snap fit features in use.

In other embodiments the complimentary engagement features may comprise a bayonet connection. For example, the second conduit portion may be provided with a series of projections (for example on its outer surface) and the aperture of the integral housing may be provided with corresponding tabs with which the projections may engage when rotationally aligned. The complimentary engagement features may further comprise a latch arrangement for maintaining the rotational alignment between the second conduit portion and the integral housing in the assembled position. The latch arrangement may comprise at least one sprung pin which engages a corresponding opening in the assembled configuration. A plurality of latch arrangements may be provided at circumferentially spaced apart positions. The latch may be provided with an externally accessible feature for reversing the engagement of the latch.

In a further aspect of the present invention, there is provided an aircraft fuel system comprising a ball valve according to an embodiment of the invention. While the invention has been described above, it extends to any inventive combination set out above, or in the following description or drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figures 1 is a cross sectional side view of a prior art aircraft fuel system ball valve showing the valve in both a closed and open configuration;

Figure 2a shows a three dimensional views of an aircraft fuel system ball valve in accordance with a first embodiment of the invention;

Figure 2b shows a cross sectional view of the valve of figure 2a;

Figure 2c shows a detailed section of the view of figure 2b;

Figures 3a to 3c show a cross sectional view of an aircraft fuel system ball valve in accordance with a second embodiment; and

Figures 4a and 4b show the interfaces of the components of the embodiment of figure 3 in a disassembled configuration. An aircraft fuel system ball valve 100 in accordance with a first embodiment of the invention is shown in Figure 2. The general configuration and operating function of the valve is similar to that of prior art ball valves. The valve 100 comprises a ball member 112 (not visible in Fig 2a) which includes a central axial bore and which may be turned through a quarter turn between an open and closed position to control flow therethrough. The valve is operated via a valve drive stem 117 which may for example be connected to a gear or handle depending upon the application of the valve. The valve stem 117 extends from one side of the ball member 112 and the ball member is rotatable mounted at the opposing side to the ball housing via a spindle 118.

In contrast to prior art ball valves which comprise a complex assembly of multiple components the ball valve 100 according to embodiments of the invention has an integral valve body housing 120 which includes a support member portion 116, a ball housing portion 115 and a first conduit portion 113. The integral housing 120 is formed from moulded PEEK plastic which may include carbon reinforcement for both strength and electrical bonding.

On the opposite side of the ball housing portion 115 to the first conduit portion 113 a separate component is provided in the form of a second conduit member 114. For easy of understanding the second conduit member 114 is show in a different shading in the figures (but it will be appreciated that it would typically be formed from the same carbon reinforced PEEK as the main body). The second conduit portion 114 is configured to be received in an aperture 122 of the integral body housing 120. The ball member 112 is captive within the housing mounted on the spindle 118 and the valve drive stem 117 and between the two conduit portions 113, 114.

As best seen in figures 2b and 2c, the end section 130 of the second conduit portion 114 and the aperture 122 are provided with complimentary engagement features to provide a snap fit engagement. The end section 130 is formed with a double walled end section including an inner 131 and outer 132 annular sections. Both the inner 131 and outer 132 walls include sealing surfaces which carry or engage with a compliant seal such as an O-ring 133a, 133b. The outer surface of the outer wall 132 further includes an external radially outwardly extending ridge or projection 134. The projection is configured to be received in a corresponding recess 124 formed on the inner face of the aperture 124 when the valve 100 is in the assembled configuration. As the body 120 and conduit member 114 are both formed from a plastic material they will resiliently when the conduit 114 is inserted into the aperture 122 during assembly. Once the axial alignment of the conduit 114 reaches the correct position the ridge or projection 134 will snap fit into the recess 124 and retain the conduit.

It may be noted that at least a portion of the recess 124 is provided with a through hole 125. This through hole enables external access to the outer surface of the ridge or projection 134 when in the assembled configuration. Thus, the ridge or projection 134 may be urged radially inwardly out of its seat in the recess 124 when disassembly of the valve is required (for example during maintenance).

An alternate embodiment of the invention is shown in figures 3 and 4. This embodiment replaces the snap fit engagement features of the previous embodiment with a bayonet fitting arrangement. Corresponding components in this embodiment are given like reference numerals to the preceding embodiment increased by 100. The general configuration of the valve assembly 200 corresponds to that of the previous embodiment (i.e. it includes an integral housing 220) and will not be described in further detail other than the interconnecting complimentary arrangement between the housing 220 and the conduit member 214. It will be appreciated that a bayonet connection is generally one in which parts may be assembled together in a first angular orientation and then rotated to a second angular orientation in which the parts are axially coupled together.

As best seen in figure 4, the corresponding faces of the conduit member 214 and integrated housing 220 are respectively provided with three circumferentially spaced apart bosses 232a, b and c and tabs 224a, b and c. When the parts are brought together the bosses 232 and tabs 224 are alternately interspersed; once the conduit is in the correct axial alignment within the aperture 222 of the housing 220 the conduit 214 may be relatively rotated such that the bosses 232 are rotated behind the tabs 224 and retain the axial alignment of the components.

As best seen in figure 3, the embodiment of figure 3 and 4 is also provided with a latching arrangement in the form of sprung pins 225 on the housing 220 arranged to engage corresponding apertures 235 on the conduit 214. The sprung pins 225 are biased outwardly and are pushed axially rearwardly (i.e. against their bias) into their recesses when the conduit 214 and housing 220 are first brought together. Rotation of the conduit into the position in which the tabs 224 and bosses 232 engage also brings the sprung pins 225 into alignment with the corresponding apertures 235. Thus the sprung pins 225 will be urged back into their forward position and will engage the apertures 235. The sprung pins 225 therefore latch the conduit 214 in the retained position and prevent further rotation or reverse rotation which would move the tabs 224 and bosses 232 out of engagement. In order to allow for disassembly, the apertures 235 which the sprung pins 225 engage are open at their opposing end. This allows a tool 250 to be inserted to urge the pins 225 back out of the aperture 235 and allow relative rotation to disconnect the bayonet fitting.

As exemplified by the two embodiments described above, embodiments of the invention may provide advantages of reduced complexity and component count. This may also simplify or reduce cost of manufacturing and/or allow for reduced manufacturing. Additionally, or alternatively, embodiments may provide a valve with reduced weight and/or cost in comparison to existing ball valve designs. Various modifications will be apparent to those skilled in the art without departing from the scope of the invention as defined in the appending claims.