AU2010203067B2 - A reflux valve and a pipeline installation including the reflux valve - Google Patents

Abstract

This invention generally relates to a reflux valve and also extends to a reflux valve installation and a pipeline installation including the reflux valve. The reflux valve, 5 comprising: a valve housing defining an inlet and an outlet and a flow passage extending from the inlet to the outlet, the housing further defining an access port providing access to the flow passage. A removable closure removably mounted over the access port in a close position to close off the flow passage, and that can be removed to open up the flow passage for providing access to the flow passage 10 within the housing. A valve member received within the housing which permits flow through the housing in one direction and resists flow through the housing in an opposed direction. Figure 1 to accompany the abstract. I--40

Description

1 A REFLUX VALVE AND A PIPELINE INSTALLATION INCLUDING THE REFLUX VALVE FIELD OF THE INVENTION 5 This invention relates to a reflux valve. The invention also extends to a reflux valve installation and a pipeline installation including the reflux valve. The invention also extends to a series of components for being assembled into a reflux valve, a method of forming a reflux valve installation and a method of facilitating 10 inspection or maintenance of a reflux valve received within the ground. This invention relates particularly but not exclusively to a reflux valve that is operatively coupled to a water pipeline that is upstream of a sewerage pipeline, e.g. a sewerage main that is used to drain sewerage from a domestic dwelling. It 15 will therefore be convenient to hereinafter describe it with reference to this example application. However it needs to be understood that it is capable of broader application. For example the invention could equally be applied to pipeline installations other than those connected to sewerage pipelines. Further the invention applies to reflux valves in all applications. Further the invention is 20 not limited to domestic plumbing installations associated with residential dwellings. BACKGROUND TO THE INVENTION The reference to any prior art in this specification is not and should not be 25 taken as an acknowledgement or any form of suggestion that the referenced prior art forms part of the common general knowledge in Australia. A reflux valve is a valve that is operatively coupled in line with a pipeline for operatively resisting reflux flow or backflow through the pipeline. The reflux valve 2 permits the passage of water in one direction and actively resists the flow of water in an opposite direction through the valve. The reflux valve typically comprises a housing having an inlet and an outlet 5 and a flow passage extending between the inlet and the outlet. The valve includes a valve seat and a valve member for closing off the flow passage when it bears against the valve seat. The valve member is spaced away from the valve seat when in an open position for permitting the flow of water through the valve. 10 The valve member may be in the form of a flap that can pivot in one direction only whereby to permit flow in a downstream direction but resist flow in the reverse direction. Thus the inlet and outlet are operatively coupled to upstream and downstream sections of the pipeline to which the reflux valve is to be coupled. 15 In some plumbing environments an overflow pipe from a house or the like is operatively coupled to a sewerage pipe whereby to direct overflow water into the sewerage pipe. In these cases a reflux valve is required to resist flow of water in a reverse direction from the sewerage pipe back into the domestic water pipe. This 20 might typically occur when there is a blockage or the like in the sewerage pipe. Often the valve member of a reflux valve encounters wear over time and maintenance needs to be carried out on the reflux valve. For example the valve member can get stuck in its closed position thereby blocking the pipe. Instead in 25 another example the valve member can get stuck in the open or closed position thereby ceasing to perform its function of resisting flow in a reverse direction. Typically the sewerage pipes are subterranean pipes that are located under the ground. Accordingly if maintenance is required to be done on the reflux valve, 30 in the absence of any engineered access to the reflux valve, a pit will need to be 3 excavated to provide access to the reflux valve. It will be appreciated that this can be a very time consuming and expensive task Further gaining access to the interior of a pipeline that is coupled to a 5 sewerage pipeline is an unpleasant task for a worker. The environment is dirty and unpleasant and the odour is harsh. It would be advantageous if the task of accessing the reflux valve member to perform maintenance on the valve member could be eased. It would save time 10 and therefore money. It would also be advantageous if the task could be accomplished without a worker having to put their hands and arms into a sewerage environment. SUMMARY OF THE INVENTION 15 According to one aspect of this invention there is provided a reflux valve, comprising: a valve housing defining an inlet and an outlet and a flow passage extending from the inlet to the outlet, the housing further defining an access port 20 providing access to the flow passage; a removable closure removably mounted over the access port in a close position to close off the flow passage, and that can be removed to open up the flow passage for providing access to the flow passage within the housing; and a valve member received within the housing which permits flow through the 25 housing in one direction and resists flow through the housing in an opposed direction. The reflux valve may include a locking arrangement for releasably locking the removable closure on the housing in an operative position over the access 30 port.

4 The valve member may be mounted on the removable closure whereby to enable the valve member to be withdrawn from the housing when the removable closure is lifted off the housing, and to enable it to be lowered into the housing through the access port when the removable closure is returned to the housing. 5 The valve member may be movable between an open position in which it opens the flow passage to permit flow through the housing in one direction and a closed position in which it closes off flow through the flow passage in another direction. 10 The valve member may be pivotally mounted on the closure and the valve member may pivot between the open and closed positions. The valve member may comprise a substantially annular flap that is pivotally mounted to the closure such that it can pivot through a pivot range of 80 to 90 degrees. 15 The removable closure may be sized to permit the valve member to be withdrawn there through with some clearance. Conveniently the shape of the removable closure complements that of the access opening. In one form the removable closure may have a substantially circular configuration and the access 20 opening may have a substantially complementary circular configuration. The removable closure may have an inner surface facing into the flow passage when it is mounted on the housing and an outer surface facing away from the housing when it is mounted on the housing and the valve member may 25 be pivotally mounted to the inner surface of the removable closure. The housing may include a substantially planar operatively upper surface, and the access port may be defined in the substantially planar operatively upper surface. In one form the housing may be described as having a compact box-like 30 shape with the access port defined in an operatively upper the top surface of the box.

5 The housing may be configured so that the upper surface of the housing is offset a small distance from regions of the inlet and the outlet that are closest thereto. 5 In particular the housing may be sized so that the upper surface of the housing, e.g. and the closure, is laterally offset a small distance from the operatively uppermost regions or points on the inlet and the outlet. The closure may be offset a distance of less than 50mm, e.g. less than 20 mm, in a direction transverse to the direction of flow from the inlet to the outlet from the regions or 10 points on the inlet and the outlet that are closest thereto. Consequently the flow passage through the housing extends directly from the inlet to the outlet, e.g. in defines a substantially linear path, and there is no significant branch defined in the flow passage in between the inlet and the outlet. 15 In particular there is no significant branch defined in the flow passage adjacent to the access opening and no appreciable dead volume within the housing that is prone to low flow and accumulation of waste. The locking arrangement may include a locking plate that is mounted over 20 the removable closure and locked onto the housing to lock the removable closure in the close position extending across the access port, and the removable closure may be sandwiched between the locking plate and the housing when the locking plate is locked onto the housing. 25 The housing and the locking plate may have complementary locking formations that can be engaged to lock the closure onto the housing and which can be disengaged to permit the closure to be detached from the housing. In particular the housing may have housing locking formations and the 30 locking plate may have plate locking formations that are engaged with said 6 housing locking formations to lock the locking plate with the closure in the close position extending across the access port. The plate locking formations may be engaged with said housing locking 5 formations by displacing the plate locking formations in one direction past the housing locking formations and then rotating the plate locking formations in a direction that is transverse to said one direction whereby to lock the plate locking formations behind the housing locking formations. 10 The valve may further include a lock actuator for enabling a user to lock the removable closure onto the housing, and to unlock the removable closure to release it from the housing from a user position spaced away from the housing. The lock actuator may include a locking handle having a plate end that is 15 mounted on the locking plate and an opposed free end, wherein the locking handle co-operates with the locking plate in such a way that rotation of the locking handle is transmitted to the locking plate. The plate end of the locking handle may be fixed to the locking plate so as 20 to be fast therewith. The locking handle may have a gripping formation mounted over the opposed free end, whereby to assist a user to manually grip the locking handle and rotate it. 25 The gripping formation may include an enlarged head and stub arms projecting away from opposed sides of the head, and the stub arms may assist a user to apply sufficient rotational force to the locking handle to rotate the locking plate. 30 7 The locking handle may be hollow. Conveniently the locking handle may be circular and may be formed by a section of plastic pipe having one end and an opposed end, e.g. having a diameter of 50 mm, and the gripping formation may close off the open end of the plastic pipe at said opposed end. 5 The locking plate may include a mounting formation formed on its outer surface defining a bore within which said opposed end of the locking handle is received. 10 The closure may include a closure handle having a closure end that is attached to the closure and a free end, for lifting the closure off the access opening on the housing and for returning the closure to the access opening on the housing. The free end of the closure handle may be spaced from the closure whereby to enable a user to operate the closure arrangement from a position 15 spaced away from the closure. The closure handle may be received within the locking handle with some clearance, whereby to permit the locking handle to be rotated relative to the closure handle without interfering with the closure handle. 20 The closure handle may be circular and the closure handle may be permanently attached to the closure. The closure handle may be formed of a section of plastic pipe, e.g. having a diameter of 40mm. 25 The closure may include a mounting formation defined on its outer surface defining a bore within which the closure end of the closure handle is received. The closure handle may have a length that is selected so that its opposed free end terminates short of the opposed free end of the locking arrangement 30 handle, whereby the closure handle is received within the locking handle when the locking arrangement locks the closure onto the housing.

8 The housing may define a valve seat which is configured and positioned so that the valve member bears against the valve seat when the valve member is in the closed position. 5 The housing may include a housing wall defining an external form of the housing, and a pipe section projecting into the housing having one pipe end against which the valve member bears and another pipe end which forms the inlet of the housing. Said one pipe end may form the valve seat which is in the form of an annular valve seat. 10 Said one pipe end may form a stop for resisting the valve member from moving in a way that would permit matter to flow in a reverse direction through the flow passage. 15 Conveniently the pipe section may be formed integrally with the housing wall, e.g. in a moulding operation. The valve may further include a seal on the valve member for sealing the valve member to the valve seat, e.g. in the form of a flap seal or O-ring mounted 20 on the valve member. The valve may include a further seal for sealing the closure to the housing around the circumference of the access port, e.g. in the form of a ring mounted on the housing and extending around the circumference of the access port. 25 The valve may further include an access shaft. According to another aspect of this invention there is provided a reflux valve installation that is received within the ground, including: 9 a valve housing defining an inlet and an outlet and a flow passage extending from the inlet to the outlet, the housing further defining an access port providing access to the flow passage; a removable closure removably mounted over the access port in a close 5 position to close off the flow passage, that can be removed to open up the flow passage for providing access to the flow passage within the housing; a valve member received within the housing which permits flow through the housing in one direction and resists flow through the housing in an opposed direction; and 10 an access shaft extending up from the housing to the ground surface with the access port communicating with the access shaft, wherein the housing is received within the ground spaced beneath the surface thereof, and the access shaft provides access to the access port from the ground surface. 15 The reflux valve installation may include a locking arrangement for releasably locking the removable closure on the housing in an operative position over the access port. 20 The valve housing, the closure, the valve member and the locking arrangement may have any one or more of the optional features of these components that are defined in the first aspect of the invention above. The locking arrangement handle may be sized, e.g. cut to length, such that 25 it is accessible to a worker on the ground surface when the cover is removed. In particular the gripping formation on the locking arrangement handle may be positioned proximate the ground surface and the cover, e.g. it may be positioned 5cm to 60 cm below the cover. Conveniently it may be positioned 5 cm to 30 cm below the cover. 30 10 Similarly the closure handle may also be sized, e.g. cut to length, such that it is accessible to a worker on the ground surface when the cover is removed. In particular the gripping formation on the locking arrangement handle may be positioned proximate the ground surface and the cover, e.g. it may be positioned 5 5cm to 60 cm below the cover. Conveniently it may be positioned 5 cm to 30 cm below the cover. Naturally the closure handle will terminate at a lower position than the locking arrangement handle so that it can be received beneath the gripping 10 formation. The access shaft may have a height of 1 to 5 m. Often the pipe may be located 1-2m beneath the ground surface in which case the access shaft will be of a corresponding height. 15 The installation may further include a removable cover mounted over the access shaft adjacent to the ground surface. The removable cover need not be sealed against the passage of fluid including water from the shaft out onto the ground surface. 20 According to another aspect of this invention there is provided a pipeline installation, including a reflux valve installation as described in the preceding aspect of the invention; and an upstream pipe section operatively coupled to the inlet and a downstream 25 pipe section that is operatively coupled to the upstream pipe section, the upstream and downstream pipe sections being received within the ground spaced below the surface. According to another aspect of the invention there is provided a series of 30 components for being assembled into a reflux valve, the series of components including: 11 a valve housing defining an inlet and an outlet and a flow passage extending from the inlet to the outlet, the housing also defining an access port for providing access to the flow passage; a removable closure for being removably mounted on the access port to 5 close the access port when mounted thereon, and to provide access to the flow passage within the housing when removed therefrom; and a valve member for being mounted to the removable closure in a way that permits the valve member to be displaced relative to the housing whereby to permit flow through the housing in one direction and resist flow through the 10 housing in another direction. The series of components may include a locking arrangement for releasably locking the removable closure onto the housing extending across the access port 15 The locking arrangement may include a locking plate for mounting over the removable closure when it is placed in position extending across the access port, wherein the locking plate and the housing have complementary locking formations which can be engaged to lock the locking plate onto the housing with the 20 removable closure clamped between the locking plate and the housing, and which can be released to permit the locking plate to be lifted off the housing. The valve member may be mounted on the removable closure whereby to enable the valve member to be withdrawn from the housing when the removable 25 closure is lifted off the housing, and to enable it to be lowered into the housing through the access port when the removable closure is returned to the housing. The valve member may be movable between an open position in which it opens the flow passage to permit flow through the housing in one direction and a 30 closed position in which it closes off flow through the flow passage.

12 The valve member may be suitable for being pivotally mounted on the closure. In particular the valve member may comprise a substantially annular flap that is capable of being pivotally mounted to the closure such that it can pivot through a pivot range of 80 to 90 degrees. 5 The locking arrangement may include a locking plate that can be mounted over the removable closure and locked onto the housing, for locking the removable closure in the close position extending across the access port with the closure sandwiched between the locking plate and the housing. 10 The housing and the locking plate may have complementary locking formations for being engaged to lock the closure onto the housing and which can be disengaged to permit the closure to be detached from the housing. 15 The locking arrangement may further include a locking handle having a plate end for attachment to the locking plate and an opposed free end. The closure may have a closure handle having a closure end for attachment to the closure and an opposed free end. 20 The locking handle may comprise a section of pipe having open ends that can be cut to length. Similarly the closure handle may comprise a section of pipe having open ends that can be cut to length. 25 The closure handle may be sized to be received within the locking handle with some clearance. Further the closure handle may be sized so that the opposed free end thereof can be received within and spaced axially in from the opposed free end of the locking handle.

13 The locking arrangement may further include a gripping formation for mounting over the opposed free end of the locking handle. The series of components may further include a hollow member sized and 5 configured for use as an access shaft. According to another aspect of this invention there is provided a method of forming a reflux valve installation coupled inline with a pipeline received within the ground, the method including: 10 installing a valve housing inline with the pipeline, the valve housing having an inlet coupled to an upstream part of the pipeline, and an outlet coupled to a downstream part of the pipeline, with a flow passage extending from the inlet to the outlet, the valve housing also including an access port for providing access to the flow passage within the housing, and a removable closure that is removably 15 mounted on the housing extending across the access port; providing a valve member within the housing that permits flow through the housing in one direction and resists flow through the housing in an opposed direction; providing an access shaft over the housing that communicates with the 20 access port, the access shaft extending from the housing up to the ground surface whereby to facilitate access into the flow passage within the housing from the ground surface. The method may including mounting a valve member on the removable 25 closure whereby to remove the valve member from the housing when the closure is lifted off the housing. The method may include excavating ground when the reflux valve housing is coupled to the pipeline. 30 14 The method may include filling in the excavation when the access shaft has been installed in position over the access opening. The method may include mounting a cover plate over an upper end of the 5 access shaft. According to another aspect of this invention there is provided a method of facilitating inspection or maintenance of a reflux valve forming part of a reflux valve installation received within the ground below the ground surface, the reflux 10 valve installation including a valve housing defining an inlet and an outlet and a flow passage extending from the inlet to the outlet, the housing further defining an access port providing access to the flow passage; a removable closure removably mounted over the access port in a close position to close off the flow passage, and that can be removed to provide access to the flow passage; a valve member 15 received within the housing which permits flow through the housing in one direction and resists flow through the housing in an opposed direction; and an access shaft communicating with the access port and extending up to the ground surface, the method including: lifting the removable closure off the access port using access provided 20 through the access shaft; lifting the valve member out of the housing through the access port and up through the access shaft to the surface; inspecting or maintaining the valve member; lowering the valve member back into the housing through the access shaft 25 and through the access port; mounting the closure over the access port to close off the flow passage. The valve member may be mounted on the closure, in which case the method may include lifting the closure up the access shaft whereby to raise the 30 valve member attached thereto to the surface, and lowering the closure back down the access shaft and onto the housing over the access port whereby to 15 lower the valve member back down the access shaft and through the access opening into the housing. The closure may include a closure handle, in which case the closure may 5 be lifted up the access shaft and lowered down the access shaft by a user holding the handle. The reflux valve installation may include a locking arrangement for locking the closure in position on the housing extending across the access opening, in 10 which case the method may include unlocking the locking arrangement prior to lifting the closure up the access shaft, and locking the locking arrangement when the closure has been lowered into position on the housing extending across the access port. 15 The locking arrangement may include a locking plate and complementary locking formations on each of the housing and the locking plate, in which case unlocking and locking the locking arrangement may include rotating the locking plate relative to the housing 20 The reflux valve installation may include a cover plate removable mounted in a position extending across an upper end of the access shaft, in which case the method may include removing the cover plate to provide access to the access shaft, and then to cover up the access shaft once the work has been completed. 25 Inspecting or maintaining the valve member may include removing the valve member from its attachment to the closure and replacing it with another valve member. Further the valve member may include a peripheral seal, and inspecting or 30 maintaining the valve member may include removing the seal and replacing it with a new seal.

16 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A reflux valve and a reflux valve assembly in accordance with the invention may manifest itself in a variety of forms. It will be convenient to hereinafter 5 describe in detail a preferred embodiment of the invention with reference to accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of 10 the preceding broad description. In the accompanying diagrammatic drawings: Fig 1 is a schematic sectional front view of a reflux valve in accordance with one embodiment of the invention; 15 Fig 2 is an exploded three dimensional view of the reflux valve of Fig 1; Fig 3 is an upper three dimensional view of the reflux valve of Fig 1 shown in an assembled condition; 20 Fig 4 is a schematic sectional front view of a pipeline installation in accordance with one embodiment of the invention; Fig 5 is a schematic sectional front view of the pipeline installation of Fig 4 with the access cover removed exposing the locking arrangement including the 25 locking arrangement handle; Fig 6 is a schematic sectional front view of the pipeline installation of Fig 4 with the locking arrangement removed exposing the closure and the closure handle; 30 17 Fig 7 is a schematic sectional front view of the closure and attached handle being removed from the access shaft to enable maintenance to be performed thereon and to provide access to the interior of the valve housing. 5 In Figs 1 to 3 reference numeral 10 refers generally to a reflux valve in accordance with the invention. The reflux valve 10 comprises broadly a valve housing 12 defining an inlet 14 and an outlet 16 and a flow passage 18 extending from the inlet 14 to the outlet 10 16. The reflux valve 10 includes a valve member 22 positioned within the housing 12 so as to permit flow through the housing 12 in one direction and resist flow through the housing 12 in an opposite or reverse direction. The housing 12 also defines an access port 20 providing access to the flow passage 18 and a removable closure or lid 24 removably mounted over the access port 20 for 15 providing access to the valve member 22 within the housing 12. The reflux valve 10 includes a locking arrangement shown generally by numeral 26 for releasably locking the removable closure 24 on the housing 12 over the access port 20. The locking arrangement 26 includes a locking plate 28 20 for mounting over the closure 24 and locking it in a closed position closing off the access port 20. The locking plate 28 is locked to the housing 12 in a position in which it is on top of the closure 24 and thereby holds it in position over the access port 20 sealingly engaged therewith. 25 The locking arrangement 26 includes a lock actuator in the form of a locking arrangement handle 30 that is mounted on the locking plate 28. The handle enables a user to lock the removable closure 24 onto the housing 12 from a user position that is spaced away from the housing 12. The handle also facilitates a user being able to unlock the closure 24 to enable it to be released 30 from the housing 12 in a similar way.

18 The flow passage 18 extends substantially linearly from the inlet 14 to the outlet 16, e.g. in a straight line along a linear flow passage axis. The closure 24 is mounted on the housing 12 in a way that forms a continuation of a wall 29 of the housing 12 whereby to preserve this linearly extending flow passage. 5 Specifically the closure 24 and the associated region of the housing 12 does not form a detour or a blind end or a branch from the flow passage 18 extending in a line from the inlet 14 to the outlet 16. 10 The reflux valve 10 includes a valve seat 32 received within the housing 12 against which the valve member 22 seats in use. In the illustrated embodiment the valve seat 32 is spaced radially in from the wall of the housing 12 around the circumference of the seat 32. 15 The valve seat 32 is formed by a pipe section 34 of smaller radius than the width and height dimensions of the wall of the housing 12 in line with the valve seat 32. The end of the pipe section 34 forms said annular valve seat 32 against which the valve member 22 can bear around the perimeter of the flow passage 18. The valve seat 32 forms a stop that resists the valve member 22 from pivoting 20 past its closed position. The valve member 22 is mounted to the closure 24 so that the valve member 22 is removed from the housing 12 with the closure 24 when it is lifted off the housing 12, The valve member 22 comprises a flap of annular shape that can 25 pivot through a pivot range of 80 to 90 degrees. In the closed position the flap 22 extends at an angle of 70-90 degrees to a horizontal axis. The valve member 22 will tend to rest on the valve seat 32 due to its weight and this will bias the valve member 22 to the closed position, 30 The valve member 22 includes a seal 35 on the valve member 22 in the form of an annular O-ring for sealing the valve member 22 to the valve seat 32.

19 The access port or opening 20 defined in the housing 12 may be broadly circular in shape and the closure 24 may be of a corresponding circular shape. The closure 24 is sized to seal against a closure seat 36 on the outer surface of the wall of the housing 12 around the periphery of the access port 20. The 5 closure seat 36 has a gasket 38 or sealing material associated therewith for sealing the closure 24 to the closure seat 32 with a fluid tight seal around the access port. The housing 12 has an upstanding wall portion 40 extending up from the 10 access opening 20 and extending circumferentially around the access opening 20. The housing 12 defines a plurality of locking formations 44 on an inner surface of the wall portion 40 spaced a predetermined distance above the access opening 20. The housing locking formations 44 are spaced apart from each other 15 around the circumference of the wall portion 40 and define spaces between each pair of adjacent locking formations 44. The locking plate 26 defines complementary plate locking formations 46 on its outer surface at spaced apart intervals around the circumference of the locking 20 plate 26. In the locked position these plate locking formations 46 are positioned below the housing locking formations 44 whereby to lock the plate 26 onto the housing 12 with the closure 24 sandwiched there between. To unlock the locking plate 26, it is rotated until the plate locking formations 46 are positioned in between the housing locking formations 44, thereby enabling the plate locking 25 formations 46 to be displaced past the housing locking formations 44 and be lifted off the housing 12. The locking handle 30 is mounted on the locking plate 26 fast therewith so that rotation of the handle 30 is transmitted to the locking plate 26. Conveniently 30 the locking handle 30 is formed by cutting a piece of plastic pipe, e.g. of about 5mm diameter to a suitable length. The locking handle 30 can be permanently 20 attached to the locking plate by receiving it within a socket 60 on the locking plate 28 and solvent welding it thereto. The locking handle 30 also includes a gripping formation 62 that is mounted 5 on the free end of the locking handle 30 i.e. that is spaced away from the locking plate 26, for assisting a user to manually grip the handle 30 and rotate it. The gripping formation 62 includes a head 64 defining a socket within which the end of the pipe is received and two arms 66 extending away from opposed sides of the head 64. The gripping arms 66 assist a user to apply sufficient rotational force to 10 the locking arrangement to unlock it. The closure 24 includes a closure handle 70 mounted on the closure 24 and extending away therefrom. The closure handle 70 is used to lift the closure 24 off the housing 12 and the attached valve member 22 out of the housing 12 15 and to a point spaced away from the housing 12. The closure handle 70 is sized to be received within the locking handle 30. Conveniently the closure handle 70 is formed by cutting a piece of pipe to a suitable length that is shorter than the length of the locking handle 30. The pipe 20 may have a diameter of 40 mm so that it can be received within the locking handle 30 with some clearance. The locking handle 70 can be permanently attached to the locking plate by receiving it within a socket 72 on the locking plate 28 and solvent welding it thereto. 25 Further the length of the closure handle 70 is sized to terminate short of the end of the locking handle 30 so that it can be received therein. This way the closure handle 70 is fully received within the locking arrangement handle 30 until it is exposed by removal of the locking handle 30 and the locking plate 28 during use. 30 21 The reflux valve can conveniently be manufactured as follows. The pipe section forming the valve seat may be integrally moulded with a sidewall and bottom wall of the housing. A top wall of the housing is moulded separately. The two housing parts are then attached to each other permanently by solvent welding 5 or the like. The closure of the housing is moulded in a separate injection moulding operation as is the valve member and the locking plate. The locking handle and the closure handle are formed from standard pipe sections by cutting the pipe 10 sections to length. This is typically only done on site when the valve is about to be installed and the depth of the valve beneath the ground can be ascertained. The gripping formation that is mounted on the remote end of the locking handle is similarly moulded in a separate injection moulding operation. The two 15 seals may be purchased as 0 ring seals or separately moulded as appropriate. In use, a reflux valve is installed in a pipe line assembly where it is desired to resist liquid flow in a reverse direction along the pipeline. A typical application is where a domestic drain is coupled to a sewerage pipeline, e.g. a sewerage main, 20 and it is necessary to resist the flow of sewerage in a reverse direction into the domestic drain. If maintenance needs to be done on a valve member during the operation of an installed reflux valve, then the locking plate is unlocked and removed by 25 rotation of the locking handle. Thereafter the closure and attached valve member can be lifted off the valve through the access port. The necessary maintenance can then be done on the valve member and then it can be reinstalled. Figs 4 to 9 illustrate a pipeline installation in accordance with one 30 embodiment of the invention that is indicated generally by reference numeral 80.

22 The pipeline installation 80 includes a reflux valve 10 as described above with reference to Figs 1 to 3. Accordingly unless otherwise illustrated the same reference numerals will be used to describe the same components unless otherwise illustrated. 5 The pipeline installation 80 comprises broadly a subterranean pipeline including an upstream pipe section 82 and a downstream pipe section 84 received within the ground 86 and spaced beneath the ground surface 88. The installation 80 also includes a reflux valve 10 coupled in line with the pipeline between the 10 upstream and downstream sections 82, 84. The installation 80 also includes an access shaft 90 extending from the valve housing 12 to the ground surface 88. The access port 20 opens into the access shaft 90 such that the closure 24 faces into the access shaft 90. The pipe 15 sections 82, 84 may be located 1-2m beneath the ground surface 88 in which case the access shaft 90 will be of a corresponding height. The installation 80 further includes a removable cover 92 mounted over the access shaft 90 adjacent to the ground surface 88. The removable cover 92 is not 20 sealed against the passage of fluid including water from the shaft out onto the ground surface. The locking arrangement handle 30 is conveniently sized, e.g. cut to length, such that it is accessible to a worker on the ground surface 88 when the cover 92 25 is removed. In particular the gripping formation 62 on the locking arrangement handle 30 may be positioned proximate the ground surface 88 and the cover 92, e.g. positioned 5 cm to 30 cm below the cover 92. Similarly the closure handle 70 is sized, e.g. cut to length, such that it is 30 accessible to a worker on the ground surface 88 when the cover 92 is removed.

23 In particular the closure handle 70 may conveniently be positioned proximate the ground surface 88 and the cover 92, e.g. 5 cm to 30 cm below the cover 92. Naturally the closure handle 70 will terminate at a lower position than the 5 locking arrangement handle 30 as it is received within the locking handle 30 both in radial and axial directions. In use the reflux valve 1 is installed in line with the upstream and downstream pipe sections 82, 84 when it is originally installed in the ground 86. 10 An access shaft 90 is installed in the ground 86 that extends from the housing 12, e.g. above the access port 20, up to the ground surface 88. As a final step the removable cover 92 is mounted over the top of the access shaft 90. When it is desired to inspect the interior of the reflux valve 10, e.g. the 15 valve member 22, then the cover 92 at the top of the shaft 90 is removed exposing the interior of the access shaft 90. Thereafter the locking handle 30 and particularly the gripping formation 62 thereof is rotated to unlock the locking plate 26. This moves the plate locking formations on the locking plate 26 out from behind their retaining engagement behind the housing locking formations on the 20 housing 12. This enables the locking plate 26 and locking handle 30 to be lifted up off the housing 12 and then be lifted out of the access shaft 90. This exposes the closure 24 and the closure handle 70 to a plumber positioned at the top of the access shaft 90. The plumber can then grasp the top 25 of the closure handle 70 and lift the closure 24 and attached valve member 22 out of the housing 12 and then out of the shaft 90. The valve member 22 can then be cleaned or repaired as the case may be and then returned to the valve housing 12. Further any other maintenance that is required to be carried out inside the housing 12 can be done through the open access port 20 to the housing 12. 30 24 The valve 10 can then be reassembled as follows. Firstly the closure 24 and attached valve member 24 can be reinserted into the shaft 90 and placed in position with the valve member received within the housing and the closure mounted over the access opening. The closure 24 is mounted back in its 5 operative position extending across the access port 20 with the valve member 22 suspended therefrom received within the valve housing 12. Thereafter the locking plate 26 and locking handle 30 are returned to the access shaft 90 with the locking plate 26 and locking handle 30 passed over the 10 closure handle 70. The locking plate 26 is passed into the upstanding wall on the housing to its fullest extent and is then rotated to retain its locking formations behind those on the housing 12. This locks the locking plate 26 in position and holds the closure 15 24 firmly in position over the access port 20 with sealing engagement around the edge of the access port 20. In a final step the closure 24 is mounted over the open top of the access shaft 90. Thereafter the reflux valve 10 can be used again in the normal way. 20 An advantage of the reflux valve described above with reference to the drawings is that it provides access to a reflux valve buried in the ground as a part of a subterranean pipe. This enables a plumber to gain access to the reflux valve, and particularly the valve member, to perform maintenance work without having to 25 dig a work pit. Another advantage of the reflux valve described above is that it provides an access shaft from the ground surface down to the reflux valve spaced beneath the ground surface while still sealing off the flow passage from the access shaft by 30 means of a closure. This resists the flow of fluid material being conveyed along the pipe into the access shaft.

25 Another advantage of the reflux valve described above with reference to the drawings is that the closure can be locked in position extending across the access port from a position spaced away from the valve, e.g. on the surface of the ground above the reflux valve and associated pipe. The locking plate can be 5 unlocked and withdrawn from the access shaft by a user manipulating the gripping formation and associated arms near the surface of the ground. Yet further the closure handle extends from the closure up to an upper end that is proximate to the ground surface enabling the closure and attached valve 10 member to be withdrawn from the housing and then lifted up the access shaft and then out of the shaft. A yet further advantage of the valve described above is that the closure handle is received within the locking handle. As such it presents a single stork or 15 column extending from the valve housing up to the surface within the access shaft. Further the upper end of the locking handle is closed off by a gripping formation. This presents a neat and aesthetic appearance that provides exceptional utility. 20 A yet further advantage of the reflux valve described above with reference to the drawings is that the housing including valve seat can be manufactured by a few injection moulding operations. Conveniently the housing and a cover may be moulded in separate moulding operations and the housing is then assembled by attaching these components to each other. 25 It will of course be realized that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto, as would be apparent to persons skilled in the art, are deemed to fall within the broad scope and ambit of the invention as is herein set forth. 30 26 In the specification the term "comprising" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition 5 also applies to variations on the term "comprising" such as "comprise" and "'comprises".

Claims (20)

1. A reflux valve, comprising: a valve housing defining an inlet and an outlet and a flow passage 5 extending from the inlet to the outlet, the housing further defining an access port providing access to the flow passage a removable closure removably mounted onto the housing over the access port in a close position to seal off the flow passage, a valve member received within the housing which permits flow through the 10 housing in one direction and resists flow through the housing in an opposed direction; a locking arrangement having a lock position in which the removable closure is locked in the close position and an unlocked position in which the removable closure can be removed from the housing so as to open up the flow 15 passage for providing access to the flow passage within the housing; and the access port is configured for communication with an access shaft such that the removable closure can be removed through the access shaft.

2. A reflux valve according to claim 1, wherein the valve member is mounted 20 on the removable closure whereby to enable the valve member to be withdrawn from the housing when the removable closure is removed from the housing, and to enable the valve member to be lowered into the housing through the access port when the removable closure is returned to the housing. 25

3. A reflux valve according to claim 1 or claim 2, wherein the locking arrangement includes a locking plate that is mounted over the removable closure and locked onto the housing to lock the removable closure in the close position extending across the access port, and the removable closure is sandwiched between the locking plate and the housing when the locking plate is locked onto 30 the housing. 28

4. A reflux valve according to claim 3, wherein the housing and the locking plate have complementary locking formations that can be engaged to lock the closure onto the housing and that can be disengaged to permit the closure to be 5 detached from the housing,

5. A reflux valve according to any one of claims I to 46, further including a lock actuator for enabling a user to lock the removable closure onto the housing, and to unlock the removable closure to release it from the housing from a user 10 position spaced away from the housing.

6. A reflux valve according to claim 5, wherein the lock actuator includes a locking handle having a plate end that is mounted on the locking plate and an opposed free end, and wherein the locking handle co-operates with the locking 15 plate in such a way that rotation of the locking handle is transmitted to the locking plate.

7. A reflux valve according to claim 6, wherein the locking handle has a gripping formation mounted over the opposed free end, whereby to assist a user 20 to manually grip the locking handle and rotate it, and wherein the gripping formation includes an enlarged head and stub arms projecting away from opposed sides of the head, and the stub arms assist a user to apply sufficient rotational force to the locking handle to rotate the locking plate. 25

8. A reflux valve according to claim 7, which includes a closure handle having a closure end that is attached to the closure and a free end, for lifting the closure off the access opening on the housing and for returning the closure to the access opening on the housing. 30 29

9. A reflux valve according to claim 8, wherein the closure handle is received within the locking handle with some clearance, whereby to permit the locking handle to be rotated relative to the closure handle without interfering with the 5 closure handle.

10. A reflux valve according to any one of claims 1 to 9, wherein the housing includes a substantially planar operatively upper surface, and the access port is defined in the substantially planar operatively upper surface, and wherein the 10 housing is configured so that the upper surface of the housing is offset a small distance from regions of the inlet and the outlet that are closest thereto.

11. A reflux valve according to claim 9, wherein the upper surface of the housing and the closure is offset a distance of less than 50mm in a direction 15 transverse to the direction of flow from the inlet to the outlet from the regions or points on the inlet and the outlet that are closest thereto so that there is no significant branch defined in the flow passage in between the inlet and the outlet.

12, A reflux valve according to claim any one of claims 1 to 11, wherein the 20 housing defines a valve seat which is configured and positioned so that the valve member bears against the valve seat when the valve member is in the closed position.

13. A reflux valve installation that is received within the ground, including: 25 a reflux valve of any one of claims I to 12 ; and an access shaft extending up from the housing to the ground surface with the access port communicating with the access shaft; wherein the housing is received within the ground spaced beneath the surface thereof, and the access shaft provides access to the access port from the 30 ground surface. 30

14. A reflux valve installation according to claim 13, the access shaft has a height of I to 5 m, and further including a removable cover mounted over the access shaft adjacent to the ground surface. 5

15. A series of components for being assembled into a reflux valve, the series of components including: a valve housing defining an inlet and an outlet and a flow passage extending from the inlet to the outlet, the housing also defining an access port for 10 providing access to the flow passage; a removable closure removeably mounted onto the housing over the access port in a close position to seal off the flow passage, a locking arrangement having a lock position in which the removable closure is locked in the close position and an unlocked position in which the 15 removable closure can be removed from the housing so as to open up the flow passage for providing access to the flow passage within the housing; and a valve member for being mounted to the removable closure in a way that permits the valve member to be displaced relative to the housing whereby to permit flow through the housing in one direction and resist flow through the 20 housing in another direction

16. A series of components according to claim 15, wherein the locking arrangement includes a locking plate for being mounted over the removable closure and locked onto the housing, for locking the removable closure in the 25 close position extending across the access port with the closure sandwiched between the locking plate and the housing and a locking handle having a plate end for attachment to the locking plate and an opposed free end, and further including a closure handle having a closure end for attachment to the closure and an opposed free end. 30 31

17. A series of components according to claim 15 or claim 16, wherein the valve member can be mounted on the removable closure whereby to enable the valve member to be withdrawn from the housing when the removable closure is lifted off the housing, and to enable it to be lowered into the housing through the 5 access port when the removable closure is returned to the housing.

18. A method of forming a reflux valve installation coupled inline with a pipeline received within the ground, the method including. installing a valve housing inline with the pipeline, the valve housing having 10 an inlet coupled to an upstream part of the pipeline, and an outlet coupled to a downstream part of the pipeline, with a flow passage extending from the inlet to the outlet, the valve housing also including an access port for providing access to the flow passage within the housing, and a removable closure that is removably mounted on the housing extending across the access port; 15 a locking arrangement having a lock position in which the removable closure is locked in the close position and an unlocked position in which the removable closure can be removed from the housing so as to open up the flow passage for providing access to the flow passage within the housing; the locking arrangement includes a locking plate that is mounted over the 20 removable closure and locked onto the housing to lock the removable closure in the close position extending across the access port, and the removable closure is sandwiched between the locking plate and the housing when the locking plate is locked onto the housing, providing a valve member within the housing that permits flow through the 25 housing in one direction and resists flow through the housing in an opposed direction wherein the valve member is mounted on the removable closure; providing an access shaft over the housing that communicates with the access port, the access shaft extending from the housing up to the ground surface whereby to facilitate access into the flow passage within the housing from the 30 ground surface providing a closure handle and mounting the closure handle to the removable closure; 32 providing a tubular locking handle and mounting the locking handle to the lock plate; wherein the closure handle and locking handle are relatively dimensioned such that the closure handle can be received within the locking handle with some 5 clearance, whereby to permit the locking handle to be rotated relative to the closure handle without interfering with the closure handle.

19. A method of facilitating inspection or maintenance of a valve member of a reflux valve forming part of a reflux valve installation received within the ground 10 below the ground surface, the reflux valve installation including a valve housing defining an inlet and an outlet and a flow passage extending from the inlet to the outlet, the housing further defining an access port providing access to the flow passage; a removable closure removably mounted over the access port in a close position to close off the flow passage, and that can be removed to provide access 15 to the flow passage; a valve member mounted on the closure and when the closure is mounted over the access port, the valve member is received within the housing so as to permit flow through the housing in one direction and resists flow through the housing in an opposed direction; a locking arrangement for locking the closure in position on the housing extending across the access opening and an 20 access shaft communicating with the access port and extending up to the ground surface, the method including: unlocking the locking arrangement lifting the removable closure off the access port using access provided through the access shaft; 25 lifting the valve member out of the housing through the access port and up through the access shaft to the surface; inspecting or maintaining the valve member; lowering the valve member back into the housing through the access shaft and through the access port; 30 mounting the closure over the access port to close off the flow passage and locking the locking arrangement 33 when the closure has been lowered into position on the housing extending across the access port.

20. A reflux valve substantially as herein described in the detailed description 5 with reference to the drawings.