FIELD OF THE I NVENTION

The present invention is concerned with providing an improved valve apparatus for fluid communication with a conduit, particularly but not exclusively a conduit for a fluid, the flow of which along the conduit may be regulated by said valve apparatus in use. Aspects of the invention relate to an apparatus, to a valve assembly, to a mounting assembly and to a method. BACKGROUND

It is common practice in industry to use valves for controlling the flow of fluid along a conduit or pipe. In some instances it is desirable to control or otherwise restrict the flow of the fluid in the conduit and to achieve this control, a one-way or non-return valve may be employed. A non-return valve in fluid communication with a conduit operates by opening, and thus permitting fluid flow, when the fluid is flowing in a direction along the conduit where fluid flow is desired, but closing, and thus preventing fluid flow, when the fluid starts to flow in a direction opposing that desired direction of flow. Generally, the flow of fluid along the conduit will be substantially axial flow along the conduit. Non-return valves are commonly used in plumbing, both commercial and domestic, hydraulic systems, pipelines and other industrial, residential and commercial applications where the flow of fluid along conduits or pipes must be controlled. The fluid being controlled may be any liquid, vapour or gas as may be required. The fluid may, for example, be water or air.

In many cases, non-return valves are bulky relative to the cross-section of the conduit with which they are in fluid communication, requiring additional packaging space around the conduit to provide suitable space for the valve in use. In addition, the presence of the nonreturn valve in-line with the conduit can lead to a reduction in the bore of the conduit in which they are used and so careful matching of the valve with the conduit and the desired flow characteristics is required to ensure the valve does not adversely affect the flow of fluid carried by the conduit in normal use. When a conventional non-return valve is open, permitting fluid flow in a first, preferred direction, the fluid flow is often at least partially impeded by the presence of the valve itself. Furthermore, these relatively bulky valves can be difficult and time consuming to fit, particularly in tight or confined spaces, especially where the valve is being inserted into an existing conduit system or pipework.

Conventional valves are generally housed within a valve body. The valve body typically has coupling formations such as shoulders, flanges or other such features, arranged to facilitate connection to corresponding formations on the conduit or pipe to which the valve is to be fitted. These coupling formations often increase the overall bulk of the valve and require considerable space to be provided around the pipe or conduit in order to accomodate the valve without the valve coming into contact with or otherwise disturbing adjacent components or structures. This requires early planning to determine the most suitable location of the valve, or significant reworking and/or re-routing of the conduit to provide appropriate clearance around the conduit to accommodate the valve may be required, if it is to be installed after the conduit or pipework has been assembled in place.

When a conventional valve is fitted in-line with a conduit or pipe, it is often necessary to sever the pipe completely in order to insert the valve into the conduit. A section of the pipe is thereby removed to install the valve. Disturbing the integrity of the conduit in this way can cause the pipe to lose some of its rigidity and strength and thus has a negative effect on the life expectancy of the conduit.

One approach known to the applicant for fitting a valve, in particular a non-return valve, into an existing conduit or pipe in a compact and efficient manner, is disclosed in GB2488877B and related published pending patent applications abroad to the same applicant. However, in some applications it would be desirable to have a non-return valve which could be inserted into a slot cut into the side of a pipe or conduit in the same or similar manner to that method described in GB2488877B, but with further improvements and enhancements to the valve member. In come installations it would be advantageous to improve upon the features of the valve described in GB2488877B arranged to facilitate installation of the valve into the conduit and to simplify the installation method for the user.

It is against this background that the present invention has been conceived. At least in certain embodiments the present invention seeks to provide a robust and reliable means for controlling the flow of fluid in a conduit or pipe, whilst requiring as little disturbance to the conduit to which the valve is fitted and being easy to install.

SUMMARY OF THE INVENTION

Aspects of the present invention relate to an apparatus, to a valve assembly, to a conduit assembly and to a method. At least in certain embodiments, the valve apparatus of the present invention may require less packaging space and access around and to the conduit in order to allow the user to install the valve into an existing conduit or pipework system. Other aims and advantages of the invention will become apparent from the following description, claims and drawings.

According to an aspect of the invention for which protection is sought, there is provided a valve assembly for controlling flow of a fluid in a conduit, the valve assembly comprising: a valve mounting member; a valve member movably mounted to the valve mounting member ,the valve member being movable in a first direction from a closed position for inhibiting fluid flow through the conduit to a first open position for permitting fluid flow through the conduit; and

a stop member operable to inhibit movement of the valve member from the closed position to the first open position;

wherein the stop member is removable from said valve assembly, the valve member being movable from the closed position to the first open position when the stop member is removed. When the stop member is installed, the valve member may be prevented from moving in said first direction from the closed position to the first open position. The valve member may function as a stop valve when the stop member is inserted. When the stop member is removed, the valve member may be free to move in said first direction from the closed position to the first open position. The valve member may function as a two-way valve when the stop member is removed. Thus a single valve apparatus installed unto a conduit may operate in two different modes of operation as may be desired.

The fluid could be a gas, such as air. Alternatively, the fluid may be a liquid, such as water.

The stop member may be locatable on a first side of the valve member to inhibit movement of the valve member in said first direction. The stop member may be replaced with an insert configured to enable the valve member to move in said first direction. The insert may be configured to form a seal between the valve assembly and the conduit. The insert may be part-annular, for example.

The valve member may be movable relative to the valve mounting member in a second direction. The first and second directions may be opposite to each other. The valve member may be movable in said second direction from the first open position to the closed position.

A stop may be provided to inhibit movement in said second direction beyond the closed position. The stop may comprise a valve seat for cooperating with the valve member. Alternatively, the stop may be a projection or protuberance configured to engage the valve member. In arrangements in which a stop is provided to inhibit movement in said second direction from the closed position, the insertion of the stop member may retain or lock the valve member in said closed position. The removal of the stop member allows the valve member to operate as a one-way valve.

Alternatively, the valve member may be movable in said second direction from the closed position to a second open position for permitting fluid flow through the conduit. The stop member may be operable to inhibit movement of the valve member from the closed position to the second open position. The valve member may be movable in said second direction from the closed position to the second open position when the stop member is removed. When the stop member is installed, the valve member may be prevented from moving from the closed position to the second open position. When the stop member is removed, the valve member may be free to move from the closed position to the first open position.

The stop member may be locatable on a second side of the valve member to prevent the valve member moving in said second direction. The stop member may be replaced with an insert configured to enable the valve member to move in said second direction. The insert may be configured to form a seal between the valve assembly and the conduit. The insert may be part-annular, for example. At least in certain embodiments, the stop member may be positioned on either the first side or the second side of the valve member to control the movement of the valve member. An insert may be disposed on the other side of the valve member to form a seal between the valve assembly and the conduit. In an alternative arrangement, the valve assembly may comprise more than one stop member. For example, the valve assembly may comprise first and second stop members. The first stop member may be arranged to inhibit movement of the valve member in said first direction; and the second stop member may be arranged to inhibit movement of the valve member in said second direction. The first and second stop members may be disposed on opposite sides of the valve member. The first stop member may be replaced with a first insert configured to enable the valve member to move in said first direction. The second stop member may be replaced with a second insert configured to enable the valve member to move in said second direction. The first insert and/or the second insert may be configured to form a seal between the valve assembly and the conduit. The first insert and/or the second insert may be part-annular.

The stop member may be configured to engage the valve member to retain the valve member in said closed position. The stop member may comprise a circular member. The circular member may be configured to form a seal in the conduit. Alternatively, the stop member may comprise a substantially annular member. The annular member may have an exterior dimension substantially the same as the exterior dimension of the valve member. The valve assembly may comprise a couplingwhich movably mounts the valve member to the valve mounting member. The stop member may be arranged to engage the coupling to inhibit movement of the valve member. The coupling may, for example, comprise a valve pivot for pivotably mounting the valve member to the valve mounting member. The valve member may pivot in said first direction and/or said second direction. The valve pivot may comprise a cam. The valve pivot may be in the form of a mounting cam. In an embodiment, the stop member may be arranged to engage the coupling and/or the valve member to inhibit movement of the valve member in said first direction. The valve member may be retained in the closed position for inhibiting fluid flow through the conduit when the stop member is in engagement with the valve member and/or the coupling; and the valve member may move to the first open position for permitting fluid flow through the conduit when the stop member is removed from the valve assembly.

At least in certain embodiments, the stop member may be removable from and/or insertable into the valve assembly while the valve member is installed in the conduit. The stop member may be displaced in a radial direction. This may allow the release of fluid collected in the conduit, for example when the valve member has been used as a stop valve.

The valve assembly may comprise alignment means, such as a slot or channel, for aligning the stop member.

In a further embodiment, the stop member may be configured to form a seal between the valve mounting member and the mounting assembly.

According to a further aspect of the present invention there is provided a valve apparatus comprising a valve assembly as described herein; and a mounting assembly for securing the valve apparatus to the conduit.

The orientation of the valve assembly may be reversible relative to the mounting assembly. The orientation of the valve member may thereby be reversed within the conduit. At least in certain embodiments, the valve member may be reversed while leaving the mounting assembly in situ on the conduit. The orientation of the valve mounting member may be reversed so as to change the direction in which the valve member is movable relative to the valve mounting assembly. Thus, the valve mounting member may be reversed so as to facilitate changing the direction of fluid flow in the conduit. In an example, once the orientation of the valve mounting member has been reversed, the valve member may be movable in a second direction opposite to the direction. In a first orientation, the valve member may be movable in a first direction to allow fluid flow through the conduit in said first direction. In a second orientation, the valve member is movable in a second direction to allow fluid flow through the conduit in said second direction. In this arrangement, the first and second directions are opposite to each other.

At least in certain embodiments, the orientation of the valve mounting member may be reversed so as to reverse the direction in which fluid may pass through the valve apparatus. According to a further aspect of the present invention there is provided a valve apparatus for controlling flow of a fluid in a conduit, the valve apparatus comprising:

a mounting assembly for securing the valve apparatus to the conduit; and

a valve assembly comprising a valve member movably mounted to a valve mounting member, the valve member being movable relative to the valve mounting member in a first direction from a closed position for inhibiting fluid flow through the conduit to a first open position for permitting fluid flow through the conduit;

wherein the orientation of the valve mounting member is reversible relative to the mounting assembly. The orientation of the valve mounting member may be reversed to change the direction in which fluid may pass through the valve apparatus.

According to a still further aspect of the present invention for which protection is sought, there is provided a valve assembly for controlling flow of a fluid in a conduit, the valve assembly comprising:

a valve mounting member;

a valve member movably mounted to the valve mounting member, the valve member being movable from a closed position for inhibiting fluid flow through the conduit to an open position for permitting fluid flow through the conduit; and

an adjustable biasing means for applying an adjustable biasing force to the valve member to bias the valve member towards said closed position. The biasing force applied by the adjustable biasing means may be adjusted by a user. The valve assembly may be used to allow the flow of fluid in one direction whilst preventing rodents travelling through the conduit in the opposite direction. The valve assembly may, for example, be installed in a downpipe to allow drainage of water whilst preventing rodents travelling up the downpipe to gain access to a loft space through roof eves.

The valve assembly may comprise a coupling which movably mounts the valve member to the valve mounting member. The coupling may, for example, comprise a valve pivot for pivotably mounting the valve member to the valve mounting member. The valve member may pivot in a first direction and/or a second direction. The valve member may pivot in said first direction from the closed position to a first open position. The valve member may pivot in said second direction from the closed position to a second open position.

The biasing force applied to the valve member may be adjusted to control a flow rate through a conduit. For example, the biasing force may be increased to reduce the flow rate through the conduit. Conversely, the biasing force may be reduced to increase the flow rate through the conduit.

At least in certain embodiments, the biasing means may facilitate the valve assembly being used in conjunction with a wide variety of different fluids, with different viscosities, densities and flow rates. The fluid could be a gas, such as air. Alternatively, the fluid may be a liquid, such as water. The user may select the valve assembly appropriate for the dimensions of the conduit and then adjust the biasing means to tune the properties of the valve for a given application. In this way, a valve apparatus of a given dimension may be equally appropriate for gas, steam, or liquid by virtue of its adjustability. At least in certain embodiments, this feature may reduce parts complexity and costs, especially for a large installation where a large number of valves may be required for only a limited number of different conduit cross- sections. In an example, the valve mounting member may be reversible in its orientation within the mounting assembly. This arrangement may facilitate changing the direction in which fluid may flow through the valve apparatus. The adjustable biasing means may be arranged to selectively apply a biasing force to the valve member to bias the valve member towards said closed position regardless of the orientation of the valve mounting member within the conduit.

The adjustable biasing means may further comprise at least one spring element and a spring tension adjuster, whereby the spring element is arranged to apply a biasing force between the valve mounting member and the valve member. The spring tension adjuster may be arranged to apply a user selectable pre-load to the spring element to vary the biasing force applied to the valve member. The spring tension adjuster may comprise a locking member arranged to hold a user adjustable pre-load force against the spring element. The locking member may be arranged to provide the user with multiple discreet detents arranged to facilitate adjustment of the spring pre-load. Alternatively, the locking member may be infinitely variable, for example by engaging a friction lock. Additionally or alternatively, at least a portion of the spring element may be accommodated within a recess formed in the valve assembly. The spring element of the biasing means may be arranged to bias the valve member towards the closed position. The valve member may return to said closed position when the forces applied to the valve by the fluid in the conduit drop below a pre-defined level. In this way, the valve member may operate as a pressure controlled flow valve or a pressure relief valve depending on how the user has adjusted the biasing means and the orientation of the valve member and valve mounting member in the conduit. In addition, the biasing means may comprise a ratchet. The ratchet may aid the user in adjusting multiple valves to the same value of pre-tension, thereby facilitating maintenance and installation. According to a further aspect of the present invention there is provided a valve apparatus comprising a valve assembly as described herein; and a mounting assembly for securing the valve apparatus to the conduit.

According to a still further aspect of the invention for which protection is sought, there is provided a mounting assembly for securing a valve to a conduit, the mounting assembly comprising: a mounting member arranged to substantially extend around the periphery of the conduit; and at least one closure member mounted to an end of the mounting member; wherein the mounting strap is arranged to provide sealing means for sealing the conduit and mounting the valve assembly in the conduit when the at least one closure member is in said closed position. In an example, the mounting strap comprises a resilient, substantially omega-shaped strap. The mounting strap may comprise at least one connector for connecting the at least one closure member. The at least one connector may, for example, each comprise a hook-like formation. The mounting assembly may comprise means for fastening the at least one closure member in said closed position.

The mounting assembly may comprise a tensioning device for clamping the mounting strap around the conduit. In an example, the tensioning device comprises an over-centre clamp. Additionally or alternatively, the tensioning device may further comprise a sealing surface arranged to seal against a portion of the conduit and the valve when the tensioning device is tightened around the conduit, the sealing surface being formed from a compliant material and arranged to seal against the valve and the conduit in use. Additionally or alternatively, the mounting strap may further comprise an aperture defining a cutting guide, arranged to guide the user to mark and/or cut a slot from the conduit. The cutting guide may be sized to enable the valve to be inserted into said conduit.

The at least one closure member may comprise a sealing surface arranged to seal against a portion of the conduit and/or the valve when in the closed position. The sealing surface may be formed from a compliant material and arranged to abut and seal against the valve and/or the conduit in use. The mounting strap may be a one-piece component. For example, the mounting strap may comprise a flexible or resilient member for locating around the conduit. Alternatively, the mounting strap may comprise a plurality of pieces connected to each other.

The mounting strap may provide a guide or template to help the user mark out the exact size, shape and orientation of the slot needed to facilitate installation of the valve. The cutting guide may optionally be removed from the conduit before commencement of the cutting so as not to be in the way of the cutting tool. The mounting strap may comprise an integrated cutting guide. The cutting guide is necessarily wider than the valve with which it is to be used, and this additional width serves to provide a suitable area with which to seal against the conduit and the valve once it has been installed. It will also be apparent to the users, that in some situations, access to the valve and the conduit to which it has been installed may sometimes be limited. In such circumstances, a tensioning device, such as an over-centre clamp, or worm-drive, may be tightened or removed substantially one-handed, further facilitating installation and maintenance.

The mounting assembly may comprise at least one air inlet valve for admitting air into an interior of the conduit. The at least one air inlet valve may comprise a resiliently deformable flap arranged to cooperate with an air inlet aperture. The flap may be formed from an elastomeric material. In use, the flap may deform to open said air inlet aperture in dependence on a pressure differential between an interior and an exterior of the conduit.

According to a still further aspect of the invention for which protection is sought, a method of fitting a valve to a conduit is provided, the method comprising: placing a mounting strap around an outer surface of the conduit, the mounting strap having a cutting guide; marking the exterior of the conduit by tracing the outline of the cutting guide onto the conduit, and/or cutting the conduit along the marked outline of the cutting guide to form a slot; capping two opposing surfaces of the slot with respective first and second end members which are partially inserted into the slot; inserting a valve into the slot between the end members; and sealing the valve in the conduit between the end members using at least one closure member attached to an end of the mounting strap. The method may comprise closing opposing closure members attached to respective ends of the mounting strap. When in a closed position, the at least one closure member may seal the conduit. The at least closure member may form a seal between the valve and the conduit. The at least one closure member may be movably connected to the mounting strap. A tensioning device may be provided to urge the closure member into a closed position to form said seal. The tensioning device may operate to mounting strap around the conduit. First and second closure members may be movably mounted to opposing ends of the mounting strap. The at least one sealing member may be removable from the mounting strap to facilitalte location of the mounting strap around the conduit. If there is limited access, for example due to the conduit being locating proximal to a wall or in a corner, the at least one sealing member may be removed to enable the mounting strap to be positioned around the conduit.

Advantageously, at least in certain embodiments this method may be used reliably to install a valve into a conduit, even if the conduit has already been installed in place, yet does not necessitate severing of the conduit, but maintains its structural integrity, by installing the valve into a slot formed into the side of the conduit rather than capping a free-end. Installation of such a valve may be achieved even with limited access to the conduit, greatly improving installation costs and making regular maintenance inspections simple.

Within the scope of this application it is envisaged that the various aspects, embodiments, examples, features and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings may be taken independently or in any combination thereof. In particular, features described in connection with one embodiment are applicable to the other embodiment, except where there is an incompatibility of features.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows an exploded view of a valve apparatus according to an aspect of the present invention;

Figure 2 shows a perspective view of a mounting strap for the valve apparatus of Figure 1 , showing how a cutting guide feature integrated into the mounting strap may be employed to assist in cutting a slot into a conduit prior to the installation of the valve apparatus of Figure 1 ;

Figure 3 shows a detailed perspective view of a valve mounting member, a component part of the valve apparatus shown in Figure 1 ;

Figure 4 shows multiple perspective views of component parts of the valve apparatus of Figure 1 together comprising a biasing means for the valve apparatus;

Figure 5 shows a detailed perspective view of a valve assembly with some key elements assembled for use and some shown in an exploded view to illustrate how the biasing means of Figure 4 is assembled;

Figure 6a shows a perspective view of a closure member, Figure 6b shows a detailed view of an inner surface of a torsion cap and Figure 6c shows a detailed perspective view of a pivot axis provided by a pair of mounting bosses integrally formed with the valve mounting member, all of which are component parts of an embodiment of the valve apparatus shown in Figure 1 ; Figure 7 shows an assembly diagram illustrating how the valve assembly of Figure 5 is installed into a slot cut into a conduit;

Figure 8 shows a perspective view of a fully assembled mounting strap along with detailed views of the component parts required to install the valve assembly of Figure 5 into a conduit;

Figure 9 shows a perspective view of the valve assembly being installed into the conduit shown in Figure 8;

Figure 10 shows a perspective view of the valve assembly of Figure 9 being withdrawn from the conduit and its orientation reversed before re-insertion and installation into the conduit;

Figure 1 1 shows a cross-section view through the mounting strap and biasing means of the valve apparatus to illustrate how these components fit together when installed into a conduit;

Figure 12 shows a perspective view of the assembled mounting strap fitted to a transparent section of conduit;

Figures 13 and 14 show a variant of the mounting strap which incorporates an air inlet valve for admitting air into the conduit;

Figure 15A illustrates a longitudinal section of a valve apparatus comprising a dual valve arrangement in accordance with a further embodiment of the present invention;

Figure 15B illustrates a transverse section of the valve apparatus shown in Figure

15A;

Figure 16 illustrates a longitudinal section of a modified arrangement of the valve apparatus shown in Figure 15A. DETAILED DESCRIPTION

Figure 1 shows an exploded view of a valve apparatus 100 according to an aspect of the present invention. The valve apparatus 100 is arranged for insertion into a slot cut into the side of a conduit carrying a fluid. The valve apparatus 100 is arranged to control the rate of flow and the direction of flow F of the fluid in the conduit when installed. The valve apparatus 100 in the present embodiment may be reversed such that the direction in which the fluid may flow through the conduit may be reversed. Figure 9 and Figure 10 show this removal and re-orientation process in more detail.

Figure 1 shows an example of the valve apparatus 100 in accordance with an aspect of the present invention, having a mounting assembly 30 comprising a mounting strap 3 for securing the valve apparatus 100 to the conduit (not shown in Figure 1). A valve assembly 40 comprises a valve housing in the form of a valve mounting member 4 and a coupling 7 for movably mounting a valve member 20. In the present embodiment, the coupling 7 comprises a valve pivot 7. The valve assembly 40 is configured to be inserted into the conduit such that the valve mounting member 4 is disposed within the conduit. The valve pivot 7 comprises a mounting cam in the example shown in Figure 1. The valve member 20 is pivotably connected to the valve mounting member 4 by the valve pivot 7. Once assembled, the valve member 20 is pivotable relative to the valve mounting member 4 in first and second directions, the first and second directions being opposite to each other. The valve member 20 thereby forms a two-way valve in the conduit. The valve member 20 is pivotable from a closed position for inhibiting fluid flow through the conduit to either a first open position or a second open position. In the closed position, the valve member 20 at least substantially closes the conduit to prevent fluid flow. In said first and second open positons, the valve member 20 is disposed substantially parallel to (or at an acute angle to) a longitudinal axis of the conduit. The valve member 20 pivots in said first direction from the closed position to the first open position; and in said second direction from the closed position to the second open position. In an aspect of the invention, and in the example shown in Figure 1 , the valve apparatus 100 is further provided with a removable stop member 2, which is also configured for insertion into the conduit along with the valve mounting member 4. The stop member 2, when inserted into the valve apparatus 100, restricts the movement of the valve member 20 in the first direction. The stop member 2 is arranged to prevent the valve member 20 moving in said first direction from the closed position to the first open position. In the present embodiment the stop member 2 does not prevent the valve member 20 pivoting in said second direction. Thus, the valve member 20 is still able to pivot from said closed position to the second open position when the stop member 2 is inserted. The stop member 2 changes the valve apparatus 100 to a one-way or non-return valve which at least substantially prevents fluid flow in the conduit in a first direction. The stop member 2 may be removed from the conduit with the rest of the valve apparatus 100 remaining in place. The removal of the stop member 2 allows the valve member 20 to open in the first direction (i.e. to operate as a two-way valve). The stop member 2 may subsequently be re-inserted into the valve apparatus 100 to restrict opening of the valve member 20 in said first direction.

The removable stop member 2 facilitates the use of the same valve apparatus 100 in two different modes of operation. With the stop member 2 inserted, the stop member 2 restricts pivoting of the valve member 20 relative to the valve mounting member 4 in said first direction. The valve apparatus 100 thereby acts as a one-way valve. However, when the stop member 2 is removed from the valve mounting member 4, the valve member 20 is free to pivot about the valve pivot 7 in said first and second directions, allowing the valve apparatus 100 to act as a two-way valve. The stop member 2 further provides the advantage to the user that the stop member 2 may be inserted into the conduit, as will be described below, such that the valve member 20 is supported in said closed position to prevent fluid flow through the conduit in a first flow direction. This may be useful to allow works, such as maintenance or repairs, to be performed downstream of the valve apparatus 100. When the works are complete, the stop member 2 may be removed to allow the valve member 20 to pivot in said first direction from the closed position to the first open position such that any liquid in the conduit is released. The stop member 2 may then be re-inserted into the valve apparatus 100. The valve mounting member 4, the valve member 20 and the stop member 2 may then be removed from the conduit as a single unit, their orientation relative to the conduit may be reversed before re-insertion. The orientation of the valve member 20 may thereby be reversed relative to the conduit. The opening direction of the valve member 20 is reversed and the direction in which the valve apparatus 100 allows fluid to flow through the conduit is reversed.

There will now follow a detailed description of the component parts of the valve apparatus 100 shown in Figure 1 and how the valve apparatus 100 is installed into a conduit.

Figure 2 shows a section of a conduit C into which the user wishes to install a valve apparatus 100 in accordance with an embodiment of the present invention. Initially, the conduit is completely intact, that is to say, the user will need to cut a slot S into the conduit in a suitable position into which the valve apparatus 100 should be installed.

The user selects where on the conduit C they wish to install the valve apparatus 100 and places the mounting strap 3 of the mounting assembly 30 around the conduit C in the desired location. The user will then rotate the mounting strap 3 around the conduit C as desired, to orientate a cutting guide 3cg formed in the mounting strap 3, so as to position the aperture of the cutting guide 3cg in such a way that will afford the best accessibility to the user to the valve apparatus 100 once installed.

Once the cutting guide 3cg is in the desired position and orientation on the conduit C, they will use a marker pen, scribe, or other suitable tool to trace around the periphery of the cutting guide 3cg aperture onto the outer surface of the conduit C, so as to mark out the desired position of the conduit slot S. Once the position of the cutting guide 3cg has been marked out clearly onto the conduit C, the mounting strap 3 is removed from the conduit C, or otherwise moved out of the way, to avoid damage. The user will then use an appropriate cutting tool (not shown) to cut along the marked out portion of the conduit C, taking care to dress the cut edges using a file or other suitable tool, to ensure that the cut edges are relatively smooth, precise and free from debris. Alternatively, the user may use the cutting guide 3cg as a guide for the cutting tool such that the slot is cut in the conduit C with the mounting strap 3 in situ. The conduit slot S in the present embodiment extends only partway through the conduit C. The conduit slot S comprises opposing longitudinal edges (extending parallel to a main axis of the conduit C) and opposing transverse edges (extending perpendicular to the main axis of the conduit C). The edges of the slot will provide a conduit sealing surface CS that will be engaged and sealed against by corresponding features in the valve apparatus 100 as will be described later. It will be appreciated that prior to cutting the slot S into the conduit C, the user will ensure that the conduit C has been drained and is not pressurised. Depending on the conduit material and the nature of the fluid the conduit is to carry, it may be necessary to remove any swarf or other debris produced during the cutting of the slot S from the inner surface of the conduit prior to installation of the valve apparatus 100. Once the user is satisfied that the slot S in the conduit C has been prepared following the appropriate standards for surface cleanliness, they will then start to install the component parts of the valve apparatus 100 shown in detail in Figure 1.

The first two components of the valve apparatus 100 to be installed into the conduit C will define the upper and lower extremities of the conduit slot S, these components are a first end member 1 and a second end member 1 1. The first and second end members 1 , 11 are shown in more detail in Figure 7 and Figure 12.

The first and second end members 1 , 1 1 , each take the form of an annular ring, with a substantially continuous inner surface and a stepped outer periphery. The outer periphery is defined by two different radii, defining two distinct regions of each said first and second end member 1 , 11 , namely an insertion portion 1 i, 1 1 i, and a sealing portion 1s, 11s. The transition between insertion portion 1 i and the sealing portion 1 s is defined on each side of the end member by a shoulder or step 1 c, 11c. These steps 1 c, 1 1c, shown clearly in Figure 3, are arranged to abut the two longitudinal cut sides of the slot that extend between where the first and second end members are to be installed in use and serve to provide both a sealing function with the conduit and a guide for the user to prevent unintentional over- insertion of the end member into the conduit. The first and second end members 1 , 1 1 are formed from a plastics material. The first and second end members 1 , 11 may have an elastomeric outer surface for forming a seal with the conduit C. In a modified arrangement, the first and second end members 1 , 11 may be formed from an elastomeric material.

The insertion portion 1 i, 11 i of each of the first and second end members 1 , 1 1 , is defined by a first radius, being substantially equal to the inner radius of the conduit C, into which the first and second end members 1 , 1 1 are to be inserted. The sealing portion 1 s, 11 s of the respective first and second end members 1 , 11 is defined by a second radius, larger than the first radius and substantially equal to an exterior radius defining the external periphery of the conduit C. It will be appreciated that the valve apparatus 100 described herein is used in conjunction with a substantially circular section conduit C, the cross-sections and surface formations of the component parts of the valva apparatus 100 may be readly configured to correspond with any desired cross-section of conduit, such as oval, square or any other shape as may be desired so as to be compatible with a given conduit. The insertion portion 1 i of the first end member 1 is arranged for insertion into the slot S. To complete the installation of the first end member 1 into the slot S, the user inserts the insertion portion 1 i into the slot S and once the first end member 1 is fully inserted and the insertion portion 1 i is in abutment with the inner wall of the conduit C, the user applies a seating force in the direction of the main axis of the conduit, until the sealing portion 1 s, is seated in abutment with the longitudinal edge of the slot S. It is the function of the first and second end members 1 , 1 1 , to seat around the upper and lower transverse edges of the slot S, which form part of the conduit sealing surface CS, ensuring that the other components of the valve apparatus 100 can abut and seal against surfaces in the slot S with a uniform surface finish, and provide a reliable surface with which to provide a suitable seal.

The sealing portion 1 s of the first end member 1 has an upper face 1 sc arranged to abut and seal against the upper transverse edge of the conduit slot S and lower face 1 sv arranged to support and seal against the valve mounting member 4 or the stop member 2. The upper face 1 sc may take the form of a resilient channel with a sealing member formed from an elastomeric or rubber-like material or a suitable foam material such as EPDM foam, the channel is arranged to cooperate with the cut surface of the slot and to seal against it in use. Additionally or alternatively, the user may choose to employ a strip of PTFE tape or other suitable sealing means, to fit around the cut edges of the slot S before the first and second end members 1 , 1 1 are installed. This may be useful if the conduit is likely to see significant temperature cycles in use due to the properties of the fluid it is carrying or due to the ambient conditions surrounding the conduit. It will be appreciated that the second end member 1 1 is substantially identical to the first end member and so also has a face 1 1 sc arranged to abut and seal against the cut edge of the conduit slot S and upper face 11 sv arranged to support and seal against the valve mounting member 4 and or the stop member 2.

The method of installation of the second end member 11 follows the steps used to install the first end member 1 , but the direction of the seating force will be opposite to that used in the installation of the first end member 1 , so as to seat the second end member 11 against the lower transverse edge (as opposed to the upper transverse edge) of the slot S. The first and second end members 1 , 11 , serve to cap and seal the upper and lower edges of the conduit slot S respectively. In addition, the first and second end members 1 , 11 , serve to guide and support the main functional parts of the valve apparatus 100 that are intended to operate inside the conduit, referred to as valve assembly 40.

lower transverse edges of the slot, the user can now turn to the assembly of the remaining components of the valve apparatus 100 and in particular to the assembly of the valve assembly 40, shown in detail in Figure 5.

The valve mounting member 4, shown in detail in Figure 3, in the present embodiment takes the form of a part-circular (omega-shaped) band, the exterior diameter of the part-circular band being substantially the same as that of the interior diameter of the conduit C into which the valve apparatus 100 is to be installed. The valve mounting member 4 is formed from a resilient material such as a plastics material. At least one of the sides of the valve mounting member 4 may comprise a sealing member (not shown) for forming a seal with the first and second end members 1 , 1 1 respectively. The sealing member may be applied as a coating, for example an elastomeric coating, or may comprise a sealing ring or gasket. It will be appreciated that the specification of the material(s) selected for the valve components must be chosen based on the suitability of those materials for reliable function in the intended environment in which the valve must operate in the conduit.

The valve mounting member 4 comprises opposing first and second mounting bosses 43 disposed at opposing ends thereof. The first and second mounting bosses 43 are spaced apart and are arranged to lie substantially parallel to one another when the valve mounting member 4 is installed into the conduit C. The valve mounting member 4 comprises an insertion portion 4i and a sealing portion 4s disposed between the first and second mounting bosses 43. The insertion portion 4i is arranged for insertion into the conduit C via the slot S and is intended to abut and seal against the inner wall of the conduit C in use. The sealing portion 4s is arranged to lie partially inside the slot S and partially extend out from the slot S and upper and lower surfaces of the sealing portion 4s are arranged to abut and thus seal against the lower face 1sv and upper face 1 1sv of the first and second end members 1 , 11 respectively. Defining the boundary on each side of the valve mounting member 4, between the insertion portion 4i and the sealing portion 4s, is a step or shoulder 4c. These shoulders 4c are arranged to abut and thus seal against the two sides of the slot S joining the upper and lower edges that are sealed by the first and second end members 1 , 1 1. There are two of these step or shoulder features formed on the valve mounting member 4, as shown clearly in Figure 3 as abutment shoulders 4c. The abutment shoulders 4c provide a seal between the valve mounting member 4 (and thus the valve assembly 40) and the conduit in use, and also prevent unintended over-insertion, which may compromise the seal between the sealing portion 4s and the first and second end members 1 , 11.

mounted to the valve mounting member 4 and intended to operate within the conduit C in use. Each of the first and second mounting bosses 43 extends substantially perpendicularly from each sealing portion 4s of the valve mounting member 4. The first and second mounting bosses 43 each have integrally formed apertures defining a pair of pivot receivers 45. The two pivot receivers 45 are arranged co-axially and their centres define a pivot axis shown by the chain-dashed line P-P, about which the valve pivot 7 and thus the valve member 20 will pivot in use. The valve assembly 40 comprises the valve pivot 7, a locking clip or locking bar 12 (shown in detail in Figure 1) and the valve mounting member or valve mounting member

In the illustrated example, the valve mounting member 4 is formed from a resilient material that allows some degree of elastic deformation to facilitate assembly and disassembly of the valve assembly 40. To assemble the valve assembly 40, the first and second mounting bosses 43 are displaced apart from each other and away from their resting position, sufficient to permit the insertion of the valve pivot 7 between the first and second mounting bosses 43. The valve pivot 7 is pivotably secured to the first and second mounting bosses 43 by engagement with the pivot receivers 45 when the first and second mounting bosses 43 return to their resting position.

Once the valve pivot 7 is secured between the first and second mounting bosses 43, the valve member 20 may be pivotably secured to the valve pivot 7. In the present embodiment, the valve member 20 is secured to the valve pivot 7 by a valve member locator 27, formed by a pair of resilient clips extending from the valve member 20 and arranged to engage with the valve pivot 7 by means of a snap-fit connection around the valve pivot 7. The valve member 20 is arranged to pivot about the valve pivot 7 via the valve member locators 27. The valve member locators 27 extend from the main body of the valve member 20 and provide an axis of rotation that is offset from the main body of the valve member 20. As may be seen from Figure 1 and Figure 5 at least, the valve member 20 comprises a series of live hinges 21 extending substantially perpendicularly from the pivot axis P-P. These live hinges allow the valve member 20 to flex slightly within the conduit, enhancing the seal against the inner wall of the conduit and the inner surface of the valve mounting member 4 in use and allowing the valve member 20 to bend when in the open position, to conform with the inner surface of the conduit, effectively allowing the valve member 20 to open wider than would otherwise be possible if the valve member 20 were rigidly formed.

The locking clip or locking bar 12 is arranged to hold the first and second mounting bosses 43 in a fixed, spaced apart condition once the valve pivot 7 and valve member 20 have been

terminated by short arms, extending substantially perpendicularly from the main body. These short arms are arranged to engage with corresponding recessed formations, shown as locking bar retainers 41 (shown in Figure 3) integrally formed in each of the first and second mounting bosses 43. Once the user has assembled the valve assembly 40, the first and second mounting bosses 43 are secured to one another by installing the locking bar 12 and the user can then insert the valve assembly 40 into the slot S between the first and second end members 1 , 11. The valve assembly 40 is secured in the slot by means of the mounting assembly 30.

The mounting assembly 30 comprises the mounting strap 3 and first and second closure members 5. The first and second closure members 5 are pivotably attached to respective ends of the mounting strap 3. The first and second closure members 5 are held securely against the conduit and the valve assembly 40 by a tensioning device or fastener 55 (an example of which is shown in Figure 12). This fastener 55 is arranged to clamp the mounting assembly 30 to the conduit in use and thus seal the valve assembly 40 into the conduit slot. The mounting strap 3 and the first and second closure members 5 are configured to form a seal between the valve apparatus 100 and the conduit C when the first and second closure members 5 are closed. The assembly of the mounting assembly 30 is shown in detail in Figure 8.

The mounting strap 3 is resiliently deformable to enable location around the conduit. In the present embodiment the mounting strap 3 is formed from a resilient material such as steel, or a plastics material such as nylon. Other materials are useful. The mounting strap 3 is substantially C-shaped (or omega-shaped), having a curved profile arranged to fit around a portion of an outer surface of the conduit. Once fitted around the conduit, the lateral portions of the mounting strap 3 are biased against the outer surface of the conduit and may temporarily hold or retain the mounting strap 3 in position. The mounting strap 3 comprises an aperture forming the cutting guide 3cg, as described above. The mounting strap 3 may be opened outwardly to enable the valve assembly 40 to be inserted into the conduit after the slot has been cut in the sidewall of the aperture. Each end of the mounting strap 3 comprises a connector 35 for connecting the first and second closure members 5. The connectors 35 in the present embodiment each comprise a hook-like formation 35 arranged to provide pivotable attachment means for the first and second closure members 5. In the present embodiment the first and second closure members 5 are removably connected to the mounting strap 3.

In the present embodiment, the first and second closure members 5 are arcuate in section and are arranged to fit around a portion of the exterior surface of the conduit in use. The

second closure members 5 are provided with a pivot axis 53 (shown in detail in figure 6) arranged to couple with a corresponding connector 35 of the mounting strap 3. When coupled to the mounting strap 3 in this way, the first and second closure members 5 are free to pivot around the connectors 35 of the mounting strap 3. With the first and second closure members 5 are folded back away from each other, an inspection window is formed between them, providing a useful visual indicator to the user as to the orientation of the valve assembly 40 without having to remove the valve apparatus from the conduit. It may be seen from Figure 6a that each of the first and second closure members 5 are provided with an integrally formed cap housing 56 arranged to accommodate component parts of the valve assembly 40 that extend beyond the slot when installed for use. The feature of the cap housing 56 in each of the first and second closure members 5 is required to avoid the protruding parts of the valve assembly 40 from preventing the first and second closure members 5 from completely closing and providing an adequate seal against the conduit C in use. On an exterior face of the cap housing 56 there is provided a clip guide feature 510 arranged to engage with a tensioning device such as a fastener 55 (shown in Figure 12) or clamping band (not shown), used to clamp the valve apparatus 100 in place in the conduit in use.

Once installed, the fastener 55 applies a biasing force to the first and second closure members 5, urging them together and holding them against the valve assembly 40 and the exposed parts of the first and second end members 1 , 1 1 , effectively sealing these components in the conduit, preventing leakage therefrom.

In use, the mounting strap is secured around the conduit C and forms a seal around the slot cut into the conduit C. The strap fastener may take the form of a spring-clip type fastener 55, as shown in Figure 12; or may take the form of an over-centre clamp (not shown). In an example, not shown, the fastener 55 and the mounting strap 3 comprise sealing surfaces 51 formed from a compliant material such as a rubber-like material or EPDM foam. Other compliant materials are useful for providing a sealing surface. These sealing surfaces may extend fully or partly around the interior surface of the mounting strap 3 and the interior faces of the first and second closure members 5 so as to be in direct contact with, and thus seal against, the exterior surface of the conduit and the surfaces of the valve assembly 40, the stop member 2 and the first and second end members 1 , 11 exposed in the slot, thus providing an effective seal in use.

The valve apparatus 100 comprises a removable stop member 2. The valve apparatus 100 may be installed into the conduit C and operated as a two-way valve without the stop

one-way valve, as may be the case during maintenance, the user will release the fastener 55, open the lateral portions of the mounting strap 3 to expose the valve assembly in the slot S and then insert the stop member 2 between the valve assembly 40 and one of the end members as may be desired.

Figure 5 shows the stop member 2 in detail. The stop member 2 comprises a substantially annular member whose periphery comprises an insertion portion 2i and a sealing portion 2s. As with the valve mounting member 4, the insertion portion 2i of the stop member 2 is separated from the sealing portion 2s by a clearly defined shoulder or step 2c. This step 2c is arranged to align with the shoulder 4c on the valve mounting member 4 when the stop member 2 is correctly installed. The shoulder or step 2c is also arranged to abut the two cut edges of the slot that extend between the first and second end members 1 , 1 1 when the stop member 2 is correctly installed.

As can be seen in Figure 5, extending from the sealing portion 2s of the stop member 2 is a tab portion 2t. The tab portion 2t is arranged to abut the first and second mounting bosses 43 of the valve mounting member 4. As described herein, the tab portion 2t engages formations of the first and second mounting bosses 43 so as to resist rotation of the stop member 2 relative to the conduit C in use. Finally, extending from the tab portion 2t is an anti-rotation arm 2a, arranged to provide added security against unwanted opening of the valve member 20 when the stop member 2 is in place.

The insertion portion 2i of the stop member 2 has an outer circumference substantially equal to the interior dimension of the conduit and matching the exterior diameter of the valve member 20. It will be appreciated that, as the examples of the valve apparatus shown in the Figures are arranged for insertion into a circular section conduit, thus the aforementioned exterior dimension of the insertion portion 2i and the interior dimension of the conduit are defined by the radius of the cross-section of the conduit. If the conduit were square in section then the exterior dimension would be half of the width of the cross-section of the conduit.

The stop member 2 is arranged to engage the valve pivot 7, as shown in Figure 5, once the stop member 2 is installed in the conduit alongside the valve assembly 40. The underside of tab portion 2t of the stop member 2 may abut a flattened region of the valve pivot 7 known as a mounting cam stop 75s. This abutment between the tab portion 2t and the mounting cam stop 75s serves to inhibit pivoting movement of the valve member 20 within the valve mounting member 4. Additional means for resisting rotation of the stop member 2 is provided by an engagement between a pair of anti-rotation features 24 extending from the tab portion 2t away from insertion portion 2i. These anti-rotation features cooperate with corresponding

mounting bosses 43. Alignment of the stop member 2 with the valve mounting member 4 is provided in part by the interaction of the anti-rotation features described above and partly by the shape and width of the anti-rotation arm 2a. The anti-rotation arm 2a is arranged to fit between the first and second mounting bosses 43, the cooperation between the parallel sides of the anti-rotation arm 2a and the two opposing faces of the mounting bosses prevent any possibility for lateral play between the stop member 2 and the valve mounting member 4.

The locking bar 12 is arranged to hold the first and second mounting bosses 43 in a fixed, spaced-apart condition when the valve assembly 40 is assembled. It will be noted from Figure 5 at least, that the locking bar 12 fixes the distance between the first and second mounting bosses 43; and also provides an indication when the stop member 2 is correctly inserted into the conduit. In particular, the free end of the anti-rotation arm 2a is arranged to curve forward slightly towards the sealing portion 2s of the stop member 2 so as to abut the locking bar 12 when the stop member 2 is correctly inserted. This abutment between the anti-rotation arm 2a and the locking bar 12 provides a reliable means to resist the rotation of the stop member 2 within the conduit.

Figure 7 illustrates how the first and second end members 1 , 11 are installed into the slot S cut into the conduit C before the valve assembly 40 is installed. The first and second end members 1 , 1 1 are substantially identical to one another, but their orientations are reversed in use so that they cooperate with and seal against the respective upper and lower edges of the slot S, whilst presenting respective valve mounting member support surfaces 114 towards the space formed between the first and second end members 1 , 11 , this space being provided to accommodate the valve assembly 40 in use.

The pivot assembly 60 is adapted to permit the valve member 20 to rotate relative to the valve mounting member 4. As shown in Figures 5 and 7, the pivot assembly 60 comprises biasing means (denoted generally by the reference numeral 22) configured to provide a user- adjustable biasing force to the valve member 20 to bias the valve member 20 towards a closed position relative to the valve mounting member 4. This biasing means 22 will now be described in detail with respect to Figures 1 , 3, 4, 5 and 6 together.

The valve pivot 7 is disposed between opposing first and second mounting bosses 43. The ends of the valve pivot 7 are pivotably secured within corresponding pivot receivers 45. With reference to Figures 4d-4f, the valve pivot 7 is prevented from being misaligned between the pivot receivers by a pair of pivot shoulders 74 extending radially from the valve pivot 7. These pivot shoulders 74 abut the corresponding opposing faces of the first and second mounting bosses 43, ensuring that the valve pivot 7 remains centred therebetween. As

the valve member locators 27. These valve member locators 27 are received by a pair of corresponding grooves or pivot channels 72, arranged to maintain the alignment of the valve member 20 relative to the valve pivot 7 in use. The valve pivot 7 has a cam lobe 75 arranged to provide a surface with which to bear against the valve member locators 27 and the valve member 20 so as to resist movement of the valve member locators 27 relative to the outer surface of the valve pivot 7.

The biasing means 22 comprises opposing first and second valve biasing springs 8 for applying a biasing force to the valve member 20. As shown in Figure 4d, the valve biasing springs 8 are at least partially disposed in respective pivot spring housings 78. The pivot spring housings 78 in the present embodiment are integrally formed in the valve pivot 7. The valve biasing springs 8 are torsion springs in the present embodiment, but other types of springs are also envisaged. The biasing force is arranged to urge the valve member 20 into a closed position, where it lies substantially parallel with the valve mounting member 4. As shown in Figure 4c, the valve biasing springs 8 are each terminated by abbreviated spring coils bent in towards the centreline of the spring so as to provide surfaces by which a torsional force can be applied to the spring. The biasing means 22 comprises means for adjusting the torsion of the valve biasing springs 8 to enable a user to adjust the biasing force applied to the valve member. The adjustment means in the present embodiment comprises a torsion adjuster or locking member 9. In the example shown in Figure 4c, one end of the valve biasing springs 8 is terminated in a cam drive-arm 87 arranged to engage with a slot or pivot spring locator, integrally formed at the base of the pivot spring housings 78. The end of the valve biasing spring 8 distal from the cam drive-arm 87 is terminated with a tension adjuster arm 89, arranged to engage with the locking member 9.

The locking member 9 is shown in detail in Figures 4a and 4b. The locking member 9 is a substantially cylindrical, cup-shaped component. A first end of the locking member 9 is closed and a second end is open. The interior of the locking member 9 is substantially hollow so as to accommodate a portion of the valve biasing spring 8, the hollow interior is referred to as a locking member spring housing 98. The closed first end of the locking member 9 has an inwardly facing surface, facing towards the hollow interior of the locking member 9 and which has integrally formed therewith a slot or locking member spring locator 97 arranged to engage the tension adjuster arm 89 of the valve biasing spring. On the opposing, outwardly facing surface of the closed first end of the locking member 9, there is integrally formed a locking member adjustment slot 91 arranged to cooperate with a tool such as a screwdriver, to facilitate a user in adjusting the biasing force applied to the valve member 20 via the valve biasing spring. The user accesses the adjustment slot 91 via a torsion cap adjuster aperture 67 formed on a cover or torsion cap 6 as will be described in further detail later. As shown in Figures 4a and 4b, disposed around the periphery of the cylindrical outer surface of the locking member 9 is a plurality of regularly spaced-apart spline formations 99 extending radially outwardly from the locking member 9. The inter-spline gaps are indicated generally at 96. The spline formations 99 of each locking member 9 are arranged to cooperate and engage with corresponding formations formed in a pair of torsion caps 6, one for each valve biasing spring 8. As shown in Figure 5 and Figure 6b, the torsion cap 6 comprises a plurality of regularly spaced-apart spline formations 66 extending radially inwardly towards the centre of the torsion cap adjuster aperture 67. The spline formations 66 are arranged to cooperate with the inter-spline gaps 96 of the locking member 9. It will be appreciated that the spine formations 99 may be formed separately from the valve mounting member 4 or may be integrally formed with the valve mounting member 4.

In the examples shown, the torsion caps 6 are secured to the first and second mounting bosses 43 of the valve mounting member 4 by means of cooperating features. In the present embodiment, a male dovetail formation or securing feature 68 is integrally formed with and extends from the torsion cap 6; and a corresponding female dovetail or torsion cap retainer 46 is integrally formed in each of the first and second mounting bosses 43. When the torsion cap 6 is installed onto the first and second mounting bosses 43, the torsion cap 6 encloses the locking member 9 and the valve biasing spring 8. Depending on the torsional pre-load applied by the user, the valve biasing spring 8 may exert an axial force between the valve pivot and the torsion cap 6, urging the torsion cap 6 away from the first and second mounting bosses 43, to exert a force on the male and female dovetail features 68, 46 respectively. To counter this force and to maintain the integrity of the torsion cap 6 as a means to enclose the valve biasing spring, the torsion cap 6 is further provided with an integrally formed snap feature 64 extending from the edge of the torsion cap 6 distal from the male dovetail securing feature 68. This snap feature is arranged to cooperate with a small recess or snap retainer 44 integrally formed in the sealing portion 4s of the valve mounting member 4 at the intersection with the first and second mounting bosses 43.

To adjust the pre-tension on the valve biasing spring 8 when the valve assembly 40 is assembled, the user inserts a flat-edged tool such as a screwdriver through the torsion cap adjuster aperture 67 in the torsion cap 6 and engages the tool with the locking member adjustment slot 91 of the locking member 9. The user then exerts an axial force to the locking member to force the spline formations 99 out of engagement with the cooperating spline formations 69 in the torsion cap 6. The user will feel that the spline formations have been displaced out of engagement when the spring tension force is felt at the handle of the tool. The user may then selectively increase or decrease the pre-load on the valve biasing spring 8 as desired. The user will then lock the desired pre-load into the biasing means by reducing

69, 99 to be forced back into engagement by the axial force applied by the valve biasing spring 8. It will be appreciated that the valve biasing spring 8 is arranged to be longer in its relaxed state than the space provided for it by the distance between the torsion cap 6 and the pivot spring locator in the valve pivot 7. In this way, the user may be permitted to increase the preload significantly above what would be provided by the valve biasing spring 8 in its relaxed state without risk that the torsionally loaded spring would never be reduced in length by the torsional load applied by the user that it might slip off the pivot spring locator or the locking member spring locator 97. Similarly, it will be appreciated that the valve biasing spring 8 is arranged with a suitable coil pitch so as to avoid becoming coil-bound in normal use.

As has been described above, the valve pivot 7 is pivotably held relative to the first and second mounting bosses 43 via the pivot receiver 45, a circular aperture sized to match the exterior diameter of the ends of the valve pivot 7 and formed in the two opposing faces of the first and second mounting bosses 43. However, these pivot receivers may not necessarily extend through the first and second mounting bosses 43 as through-holes with a constant diameter. Alternatively, the external faces of the first and second mounting bosses 43 that face away from one another may have formed a cylindrical aperture arranged concentrically with the pivot receiver 45, but with an internal diameter that is different from that of the pivot receiver 45 as may be required to accommodate the valve biasing spring 8 and the locking member 9 as may be desired. The cylindrical apertures formed in the external faces of the first and second mounting bosses 43 that face away from one another provide a locking member housing 49 and, whilst they are concentrically formed with the pivot receiver 45, the diameter of the locking member housing 49 need not necessarily be identical to that of the pivot receiver 45.

It will be appreciated that the biasing means 22 illustrated in the Figures is provided by way of example only, and that other arrangements are also contemplated. For example, the biasing means 22 may comprise a single valve biasing spring 8.

Figure 9 and Figure 10 show two alternative orientations of the valve assembly 40 as part of a conduit assembly 500, where the conduit assembly comprises both the conduit and the valve apparatus 100. In Figure 9, the desired direction of fluid flow is indicated by block arrow F, and as such, the user removes the stop member 2 from the valve assembly 40 and inserts the valve assembly 40 into the slot. The valve assembly 40 is sealed in place by closing and securing the first and second closure members 5. Figure 10 shows the same conduit assembly 500, but in this arrangement, the desired direction of fluid flow is reversed from that

the first and second closure members 5, withdraw the valve assembly 40 from the conduit and reverse its direction (by rotating the valve assembly 40 through 180° about a diametrical axis) before re-insertion into the slot. The user then seals the conduit C by securely closing the first and second closure members 5. In the arrangements shown in Figure 9 or in Figure 10, the user may change the operating mode of the valve apparatus 100 by inserting or removing the stop member 2. As described herein, the valve apparatus 100 may function as a one-way or non-return valve when the stop member 2 is inserted. The valve apparatus 100 may function as a two-way valve when the stop member 2 removed.

Figure 1 1 shows a cross-section view through the mounting strap 3 and pivot assembly 60 of the valve apparatus 100 to illustrate how these components fit together when installed into a conduit. In the example shown in Figure 11 and Figure 12, the opposing first and second closure members 5 are secured in a closed position via a fastener from a metal or plastics clip arranged to engage with integrally formed connectors 35 at each free end, with a fastener receiver 54 formed in the outer face of each of the first and second closure members 5. These fastener receivers 54 are shown clearly in Figure 1 and may be used either with the simple clip arrangement or fastener 55 of Figure 12, or may alternatively be used with an over-centre clamp or band clamp, which may offer more adjustment to the user to accommodate installation of the valve apparatus onto pieces of conduit that vary slightly in cross section as may be the case with some pre-existing conduit systems.

A variant of the mounting strap 3 is shown in Figures 13 and 14. In this arrangement, the mounting strap 3 comprises at least one air inlet valve 13 for admitting air into the conduit C. As shown in Figures 13 and 14, the mounting strap 3 in the illustrated arrangement comprises first and second air inlet valves 13 disposed in the cap housings 56 provided on opposing sides of the mounting strap 3. The first and second air inlet valves 13 each comprises a flap 14 disposed in a valve housing 15, as shown in Figure 14. The flap 14 is formed from a resiliently deformable material, such as rubber or an elastomeric material. An air inlet aperture 16 is formed in the valve housing 15. The flap 14 is mounted in the cap housing 56 at least substantially to seal the air inlet aperture 16. The flap 14 is mounted in the valve housing 15 so as to cover the air inlet aperture 16 (i.e. in a closed position). A gasket 17 is disposed between the exterior of the conduit C and the mounting strap 3 to form a seal around the slot cut in the sidewall of the conduit C. An aperture 18 is formed in the gasket 17 to form a fluid path PA to an interior of the conduit C, as illustrated by the arrows 19 in Figure 13. When the pressure inside the conduit is less than the external pressure, the flap 14 is deformed to open the first and second air inlet valves 13. Air may thereby be drawn into the conduit C through the first and second air inlet valves 13. When the pressure differential between the interior and exterior of the conduit C is reduced, the flap 14 returns to

thereby reduce the pressure differential within the conduit C.

A valve apparatus 100 comprising a dual valve arrangement is illustrated in Figures 15A and 15B. The dual valve arrangement may, for example, be appropriate as an anti-flooding device for a building. The valve apparatus 100 comprises first and second valve members 20-1 , 20-2 of the type described herein installed in a conduit C. Like reference numerals are used for like components, albeit including a suffix to differentiate between the first and second assemblies.

The first and second valve members 20-1 , 20-2 are pivotally mounted to respective first and second valve mounting members 4-1 , 4-2 disposed within the conduit C. The first and second valve mounting members 4-1 , 4-2 are fastened to the conduit C by respective first and second mounting assemblies 30-1 , 30-2. The first and second mounting assemblies 30- 1 , 30-2 comprise respective first and second mounting straps (not shown) extending around the outside of the conduit C. The first and second mounting straps are secured by closure members 5-1 , 5-2. As illustrated in Figure 15A, the first and second valve members 20-1 , 20- 2 are pivotally mounted to allow fluid flow through the conduit C. The pivoting movements of each of the first and second valve members 20-1 , 20-2 may be inhibited by respective first and second stop members (not shown). It will be understood that the first and second stop members may be used selectively to inhibit movement of the first valve member 20-1 and/or the second valve member 20-2. One or both of the first and second stop members can be inserted to provide the required functionality. The method of installing the valve apparatus 100 is a development of the technique described herein in respect of the earlier embodiments. The user selects where on the conduit C they wish to install the valve apparatus 100 and locates the first mounting strap around the conduit C in the desired location. The user positions the mounting strap such that the cutting guide is positioned in the appropriate orientation and a first conduit slot S1 is formed. The user then installs the first and second end members 1-1 , 11-1 within the conduit C and inserts the first valve mounting member 4-1 which supports the first valve member 20- 1 inside the conduit. The first mounting strap is fitted and the closure member 5-2 installed. This method is then repeated for installation of the second valve member 20-2. As shown in Figures 15A and 15B, the valve apparatus 100 comprises a channel 50. The channel 50 is provided to allow the passage of silt or debris past the valve apparatus 100. As shown in Figure 15B, the channel 50 is formed in an outer perimeter of the first and second valve mounting members 4-1 , 4-2; and the first and second end members 1-1 , 1 1-1. Thus, when the valve apparatus 100 is installed in the conduit C, the channel 50 extends alongside

longitudinal direction parallel to a longitudinal axis of the conduit C. The channel 50 is located at the bottom of the conduit C to allow silt or debris collected at the bottom of the conduit C to pass the valve apparatus 100. In use, the channel 50 remains open even when the first and second valve members 20-1 , 20-2 are closed. The channel 50 may be incorporated into the valve apparatus 100 described in the other embodiments herein. It is envisaged that the channel 50 would only be used in arrangements in which the conduit C extends substantially horizontally. A plug or closure member may be provided to close the channel 50 when the valve apparatus 100 is used in other installations.

The valve apparatus 100 in the present embodiment also comprises a control member 51 for controlling opening and closing of the first and second valve members 20-1 , 20-2. The control member 51 may be used instead of, or in addition to, the stop member 2 described herein. The control member 51 is operable selectively to lock the first valve member 20-1 and/or the second valve members 20-2 in an open position and/or a closed position. The control member 51 in the present embodiment comprises a rotatable actuator comprising one or more protuberance and/or one or more recess for cooperating with the first and second valve members 20-1 , 20-2. The control member 51 may be modified to provide sliding actuation. The valve apparatus 100 could comprise first and second control members 51 for controlling operation of the first and second valve members 20-1 , 20-2 respectively. The control member 51 may be incorporated into the valve apparatus 100 described in the other embodiments herein.

As shown in Figure 16, the valve apparatus 100 may be installed such that the first and second valve members 20-1 , 20-2 are spaced apart from each other along the longitudinal axis of the conduit C.

In a variant of the valve apparatus 100, the mounting assembly is modified to retain both the first and second valve mounting members 4-1 , 4-2. In this arrangement, the mounting strap comprises first and second cutting guides spaced apart from each other. The mounting strap is arranged to mount both the first and second valve mounting members 4-1 , 4-2. One or more closure member 5 may be provided to fasten the mounting strap.

In a further variant, the first and second valve mounting members 4-1 , 4-2 may be mounted alongside each other in the same conduit slot S1 formed in the conduit C. The first and second valve mounting members 4-1 , 4-2 may be formed separately or may be connected to each. The first and second valve mounting members 4-1 , 4-2 could be formed as a single member. This arrangement may facilitate installation of the valve apparatus 100 in the

end members 1 , 1 1 installed at respective ends thereof.

Other advantages will be apparent to one skilled in the art and the present examples and embodiments are to be considered illustrative and not restrictive. The invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.