Valve

The present invention relates to a valve and a method for assembling a valve and concerns particularly a poppet valve used for a pressure test point.

Background of the Invention Poppet valves are used widely as test points in fluid systems involving pressurised media, such as air brake systems on commercial vehicles. Such poppet valve test points can include a valve stem that is arranged within a valve housing with a spring element so that by pressing the stem inwards a channel is opened to the fluid system and testing of the pressure is possible. Existing test points are constructed in metal, such as brass, and are coupled to a building block assembly by helical threads. In known test points a holding element is provided to retain internal parts like valve stems, springs and O-rings within the valve housing.

Disclosure of the Invention

According to a first aspect of the present invention there is provided a valve device for testing pressure in a pressurised fluid system, the valve device comprising a housing formed with a channel for fluid communication, a valve member and a retaining component for retaining the valve member within the housing, the valve member and the retaining component being receivable by the housing, the retaining component being securable within the housing, the valve member being axially moveable relative to the housing from a closed position to an open position wherein fluid may pass from the valve device and hence to a fluid test device, characterised in that, the retaining component comprises means for limiting the axial movement of valve member relative to the housing.

Preferably, the retaining component comprises means for limiting the axial movement in the direction towards the closed position.

The retention component preferably comprises means for limiting the axial movement in the direction towards the open position.

The means for limiting the axial movement of the valve member preferably comprises a detent section and a corresponding abutment element, wherein the detent section maybe formed in the valve member and the abutment element is formed on the retaining component or alternatively the detent section maybe formed in the retaining component and the abutment element is formed on the valve member.

In a particularly preferable arrangement the distance of relative axial movement of the abutment element within the detent substantially defines the axial movement of the valve member.

The abutment element preferably comprises a cantilever arm.

In the assembled state the distal end of the cantilever arm is preferably urged in a direction towards the detent section.

The cantilever arm is preferably formed with a hook shaped distal end.

The means for limiting the axial movement of the valve member preferably comprises two abutment elements.

The retaining component preferably comprises means for securing the retaining component within the housing. The means for securing the retaining component within the housing preferably comprises a push- fit arrangement.

The means for securing the retaining component within the housing preferably comprises a snap-fit arrangement between a radially inner surface of the housing and a radially outer surface of the retaining component.

The snap-fit arrangement preferably comprises a raised element adapted to snap-fit into a detent form, wherein the detent element maybe formed in the radially inner surface of the housing and the abutment element is formed on the radially outer surface of the retaining component or alternatively the detent element maybe formed in the radially outer surface of the retaining component and the abutment element is formed on the radially inner surface of the housing.

The valve member preferably comprises a projection and the means for limiting axial movement of the valve member is a corresponding detent formed on retention component, the detent being arranged to engage the projection to limit outward movement of valve member relative to the housing.

The valve device is preferably a poppet valve, wherein the valve member is formed with an outwardly facing generally axial bore capable of communicating with a fluid test device (not forming part of this invention) and the valve member has an inwardly facing throughway communicating in an open relative position of the valve member and the retention component with the fluid to be tested.

Preferably, the valve member has a circumferential seating and the retaining component has a circumferential abutment and a sealing element is disposed

between the seating and the circumferential abutment to affect a seal between the valve member and the retaining component.

The valve device preferably comprises means for urging the valve member toward the closed position. The means for urging the valve member toward the closed position preferably comprises a compressible element. The compressible element may comprise any suitable form or material but preferably the element is a helical spring element.

Preferably, the valve member and the retaining component are insertable into the housing in the same direction along the longitudinal axis of the housing.

The channel formed in the housing comprises one end that is open to the atmosphere and preferably the valve member and the retaining component are insertable into the channel in the housing through the end open to the atmosphere.

It is also preferable that the means for urging the valve member toward the closed position and the sealing element are insertable into the housing in the same direction along the longitudinal axis of the housing.

Preferably, at least one of the valve member or the retaining component or the means for urging the valve member toward the closed position or the sealing element is extractable from the housing in the same direction along the longitudinal axis of the housing.

The fluid channel formed in the housing preferably has a decreasing diameter in the direction of insertion of the valve member.

The valve device is preferably made from a plastics material and the components of the device, such as the housing, the valve member and the retaining component are preferably made by an injection molding process. To aid the manufacture of the valve device in a composite or plastics material a cavity or boring must be made in the material. When doing this in composite material it is favourable that the diameter of the cavity is gradually decreasing in the direction of the bore. It is otherwise difficult to extrude the kernel.

Further, the present invention provides a valve device where all internal parts are assembled from the same direction, i.e. from the front of the valve device.

The distance of relative axial movement of the abutment element within the detent substantially defines the axial movement of the valve member and affects the

compressive force of the means for urging the valve member toward the closed position.

According to a second aspect of the present invention there is provided a method for assembling a valve device according to any one or more of the features of the first aspect of the invention, wherein the method comprises inserting the valve member into the housing before inserting the retaining component.

The valve device comprises a housing formed with a channel for fluid communication, a valve member and a retaining component for retaining the valve member within the housing, the valve member and the retaining component being receivable by the housing, the hosing being formed with a channel at one end that is open to the atmosphere, wherein the method preferably comprises inserting and the valve member and the retaining component into the channel in the housing through the end open to the atmosphere.

Brief Description of the Drawings

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

Figure 1 is a cross section view through A-A of Figure 3 and shows a valve device in a closed condition;

Figure 2 is a cross section view through B-B of Figure 1 and shows the valve device in a closed condition;

Figure 3 is a view along the axis of the valve and shows the valve device in a closed condition; Figure 4 is a cross section view through C-C of Figure 6 and shows the valve device in an open condition;

Figure 5 is a cross section view through D-D of Figure 4 and shows the valve device in an open condition;

Figure 6 is a view along the axis of the valve and shows the valve device in an open condition;

Figure 7 is a side view of a valve member and a retaining component of a valve according to the invention and shows the elements in a disassembled state;

Figure 8 is an isometric view of Figure 7;

Figure 9 is an isometric view of a housing, some seal elements, a valve member and a retaining component of a valve according to the invention and a push-in coupling connector and shows the elements in a disassembled state; and ^'

Figure 10 is an isometric view of the elements shown in Figure 9 and shows the elements in an assembled state.

With reference to the figures, there is shown a valve device 1 in the form of a poppet valve, for testing pressure in a pressurised fluid system. The valve device 1 comprises a housing 2 formed with a channel 4 extending along the longitudinal axis 6 of the housing 2. The channel 4 forms a fluid communication between the opposite ends 5, 7 of the housing 2. The end 5 of the housing 2 is formed with an axial fluid port 9. Disposed partially within the housing 2 there is a valve member 8 and a retaining component 10 for retaining the valve member 8 within the housing 2. The valve member 8 has a bore 12 extending from one end of the member 8 along the axis 6 to a region distant from the other closed end of the member 8. There are two radial ports 14 that extend radially outward from the bore 12. The valve member 8 and the retaining component 10 are both insertable into the housing 2 and may also be retractable from the housing 2.

The valve device 1 comprises means for urging the valve member toward the closed position in the form of a compressible helical spring 16. The means for urging the valve member 12 toward the closed position may alternatively comprise any other suitable compressible form or material. The spring 16 is disposed within the channel 4 and extends from the closed end of the valve 8 to the end 5 of the housing 2. One end of the spring 16 abuts a shoulder 18 formed on a radially outer surface of the closed end of the valve member 8.

Within the channel 4 there is a seal element in the form of an o-ring 20. The o-ring 20 is disposed between the shoulder 18 and an annular step formed on the inner surface of the housing 2.

The valve member 8 is axially moveable relative to the housing 2 from a closed position (as shown in Figures 1 and 2) to an open position (as shown in Figures 4 and 5). In the open position fluid may pass through the valve device and hence to a fluid test device.

The valve device 1 comprises means for limiting the axial movement of valve member 8 relative to the housing 2 in the form of an annular detent section 22 formed in the valve member 8 and two corresponding abutment elements 24 extending from the retaining component 10. In an alternative arrangement the

detent section 22 maybe formed in retaining component 10 and the abutment elements 24 maybe formed on the valve member 8. In a particularly preferable arrangement the distance of relative axial movement of the abutment element 24 within the detent section 22 substantially defines the axial movement of the valve member 8.

The abutment elements 24 comprise a cantilever arm formed with a hook shaped distal end. In the assembled state the distal end of the cantilever arm is urged in a direction towards the axis 6 and into the detent section 22.

The distance of relative axial movement of the abutment element 24 within the detent section 22 substantially defines the axial movement of the valve member 8. The distance of relative axial movement of the abutment element 24 within the detent section 22 may also be used to affect or control the compressive force of the spring 16. The abutment element 24 coming into contact with the end stop of the detent section 22 can be used to reduce the force of the spring 16 pressing the shoulder 18 into with the o-ring 20.

The retaining component 10 comprises means for securing the retaining component 10 within the housing 2. The means for securing the retaining component within the housing 2 preferably comprises a push-fit arrangement. The retaining component 10 is securable within the housing 2 in the form of an annular raised rim 26 formed in the radially outer surface of the retaining component 10 and being adapted to snap-fit into an annular detent 28 formed in a radially inner surface of the housing 2. The means for securing the retaining component 10 within the housing 2 preferably comprises a snap-fit arrangement between a radially inner surface of the housing 2 and a radially outer surface of the retaining component 10. In alternative arrangement the detent element 28 maybe formed in the radially outer surface of the retaining component 10 and the abutment element 26 is formed on the radially inner surface of the housing 2.

The valve device 1 shown is a poppet valve type, wherein the valve member 8 is formed with the outwardly facing generally axial bore 12 capable of communicating with a fluid test device (not shown) and the valve member 8 has an radially inwardly facing port 14 whereby there is fluid communication in an open relative position of the valve member 8 with the port 9 and hence the fluid to be tested.

Preferably, the valve member 8 has a circumferential seating and the retaining component 10 has a circumferential abutment and a sealing element is disposed between the seating and the circumferential abutment to affect a seal between the valve member 8 and the retaining component 10.

It shall be appreciated that the valve member 8 and the retaining component 10 are insertable into the housing 2 in the same direction along the longitudinal axis 6 of the housing 2. The housing 2 comprises an end that is formed with an outer helical thread 30 that is used to attach an instrument such as a pressure gauge. The other end of the housing 2 is formed with two annular recess 32. Retained in the recesses 32 there are two o-ring seals 34. One end of the housing 2 may be inserted into a tube connector 36 (as shown in figure 9). The o-rings 34 form a sealing arrangement with inner surfaces of the tube connector 36. The tube connector 36 may form part of a fluid pressurised system as previously describe above. It is also preferable that the spring 16 for urging the valve member 8 toward the closed position and the sealing element o-ring 20 are also insertable into the housing 2 in the same direction along the longitudinal axis 6 of the housing 2.

The fluid channel 4 formed in the housing 2 preferably has a decreasing radial diameter in the direction of insertion of the valve member 8 and the retaining component 10.

As shown in figures 7, 8 and 9, the valve member 8 and the retaining component 10 are assembled into the housing 2 through the open end of the housing 2 that is formed with the thread 30. The valve member 8 enters the housing 2 before the insertion of the retaining component 10. The o-ring 20 may be placed onto the valve member 8 before the member is placed into the housing 2. The spring 16 may be placed into the housing before the valve member 8 is inserted into the housing 2 or alternatively the spring 16 and/or the o-ring 20 may be placed on the member 8 before they are placed in the housing 2. The retaining component 10 is preferably placed onto the end of the valve member 8 before they are both placed into the housing 2.

The valve device 1 is preferably made from a plastics material and the components of the device 1, such as the housing 2, the valve member 8 and the retaining component are preferably made by an injection molding process.

It shall be appreciated that the housing 2 may form part of another device within a pressurised fluid system such as a tube connector or a manifold unit. The valve member 8 and the retaining component 10 may be received within a fluid port formed in such another device within the system. The valve device 1 may work similar to known pressure test points, i.e. fluid pressure can be tested by pressing the valve stem into the test point. In resting position the valve stem will be pressed outwardly by a spring.