GB2515551A - Non-return device - Google Patents

Abstract

The invention relates to a non-return device 12 which may be used for waste and or odour traps for domestic plumbing. The device comprises a housing 18 for connection between a fluid inlet 14 and a fluid outlet 16 and a flexible non-return valve 26 positioned within the housing. The non-return valve has an inlet opening through which fluid enters the valve, and an outlet through which fluid exits the valve. The fluid outlet is defined by a pair of opposing wall members 28, 30. Opposing closure devices 40 are arranged such that each clamps a respective lateral edge of the outlet. The wall members are moveable between open and closed conditions. In the open condition the wall members define a passageway for fluid to flow out of the valve from the inlet. In the closed condition the wall members are in face to face contact to prevent fluid flow from the outlet to the inlet. The non return valve may be made by injection moulding.

Description

Non-return device

FIELD OF THE INVENTION

The present invention relates to non-return devices, with particular but not exclusive reference to waste and!or odour traps for domestic and other plumbing.

BACKGROUND OF THE INVENTION

Waste traps are provided in plumbing systems between a waste outlet (e.g. a plug hole of a sink, bath or shower) and a waste pipe, for preventing unpleasant odours or unhealthy omissions travelling from the waste pipe to the waste outlet.

The most conventional form of waste trap is a bend containing water. However, waterless' mechanical waste traps are also known, e.g. as shown in GB23203 10.

Typically, these include a non-return device having a valve configured to permit waste water to flow through the device (e.g. from a sink to a waste pipe), and to create a barrier for preventing gas flow back up through the device (e.g. from the waste pipe to the sink).

In order to be fit-for-purpose, the non-return device needs to perform in a reliable manner.

SUMMARY OF THE INVENTION

The present invention seeks to provide a reliable non-return device for use in particular, but not exclusively, between a waste outlet and a waste pipe, e.g. in a domestic plumbing system.

A first aspect of the invention provides a non-return device comprising: a housing for connection between a fluid inlet and a fluid outlet (e.g. between a waste outlet and a waste pipe in a plumbing system); and a flexible non-return valve positioncd within the housing, the non-return valve comprising an inlet defining an opening through which fluid can enter the valve, and an outlet through which fluid can exit the valve, the outlet being defined by a pair of opposing wall members, the device further comprising opposing closurc dcviccs, each arranged for clamping a respective lateral edge of the outlet; wherein the wall members are moveable between an open condition and a closed condition; in the open condition the wall members define a passageway for fluid to flow out of the valve from the inlet, and in the closed condition the wall members are in face to face contact so as to prevent fluid flow from the outlet to the inlet.

The non-return device provides a reliable and effective solution for preventing waste gases travelling from an outlet pipe to an inlet pipe. The closure devices obviate the problems of gaps arising between the wall members when the valve is in a relaxed state, and permits the non-retum valve to be formed using moulding techniques (e.g. injection or compression moulding). The closure devices help to ensure a gas-tight seal across the width of the outlet in the closed condition. The closure device further permits a fairly thick core to be used during the moulding process (i.e. more robust in production and less likely to be bent or broken).

In exemplary embodiments, the closure devices arc offset from an outlet end of the wall members, e.g. the closure devices are offset by approximately 2 mm from the outlet end of the wall members. It has been found that positioning the closure devices offTsct from the outlet end of the wall members improves location of the closure devices, i.e. reduces the risk of the closure devices being displaced during use.

In exemplary embodiments the closure devices may apply a compressive force to the wall members, and in such embodiments it is believed that the uncompressed portion of the wall members surrounding the closure devices help to locate the closure devices.

In exemplary embodiments, the flexible non-return valve is of moulded construction (e.g. produced by an injection or compression moulding technique).

In exemplary embodiments, each closure device comprises a clip (e.g. a U-shaped clip).

In exemplary embodiments, the clips are configured to apply a compressive force to the wall members. The degree of compression may reduce the thickness of the wall members by approximately 10 % from their relaxed state.

The clips may be made from plastics material or metal.

In exemplary embodiments, each closure device is a dcformable U-shaped member (e.g. made from metal or plastic) that is crimped in place.

In exemplary embodiments, the wall members are formed with a key for retaining the closure devices in place (e.g. complimentary retention members may be provided between the wall members and the closure device, such as an angled end profile or a rib and groove arrangement).

In exemplary embodiments, the closure devices have an axial length equal to or less than an axial length of an outlet portion of the valve. The closure device may have an axial length equal to or in the region of I to 35 mm. For example, the closure device may have an axial lcngth greater than or cqual to 2 mm, grcater than or equal to 6mm, less than or equal to 20 mm or less than or equal to 10mm, e.g. 7 to 8mm.

In exemplary embodiments, the wall members each have a thickness equal to or greater than 3.2 % of the width of the outlet. However, in alternative embodiments the wall members may have a thickness less than 3.2 %.

The wall members may be made from silicon rubber, an elastomer, or a thermoplastic clastomcr.

In exemplary embodiments, the wall members may be shaped such that in a region between the two closure devices the wall members connect so as to be in interference.

Such an arrangement further biases the wall members of the non-retum valve to the closed position, which can further improve the performance of the valve. For example, at least one of the wall members may be convex such that one or both of the wall members curve towards each other in a central region.

A second aspect of the provides a non-return device comprising: a housing for connection between a fluid inlet and a fluid outlet (e.g. between a waste outlet and a waste pipe in a plumbing systcm); and a flexible non-return valve positioncd within the tubular housing, the valve comprising: an inlet defining an opening through which fluid can enter the valve; an outlet through which fluid can exit the valve, the outlet being defined by a pair of opposing wall members which are connected to one another along opposing lateral edges of the outlet; and an adhesive or weld arranged for holding the pair of wall members together immediately adjacent said lateral edges of the outlet; wherein the wall members are moveable between an open condition and a closed condition; in the open condition the wall members define a passageway for fluid to flow out of the valve from the inlet, and in the closed condition the wall members are in face to face contact so as to prevent fluid flow from the outlet to the inlet.

A third aspect of the invention provides a method of producing a non-return valve for a non-return device of the first aspect, the method comprising: moulding the outlet using a core to form a separation between the pair of wall members; and positioning a closure device on each lateral edge of the outlet.

A fourth aspect of the invention provides a method of producing a non-return valve for a non-return device of the second aspect, the method comprising: moulding the outlet using a core to form a separation between the pair of wall members; and adhering or welding a region immediately adjacent each lateral edge of the outlet.

BRTEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 shows a cross section of a pipe assembly including a non-return device; Figure 2 is a plan view of an inlet of a non-return valve forming part of the non-return device shown in Figure 1; Figure 3 shows an end view of the outlet of the non-return valve of Figures 1 and 2 in a closed configuration; Figure 4 is similar to Figure 3 and sho\vs the outlet of the non-return valve in an open configuration; Figure 5 is a sectional view of a clip of the non-return valve of Figures Ito 4; Figures 6 to 8 illustrate end views of the non-return valve of Figures 2 to 4 during a method of production; Figures 9 and 10 show alternative clips to that shown in Figure 5; Figures 11 and 12 show an end view of a non-return valve incorporating alternative closure devices during a method of production; Figure 13 shows alternative configurations clips or closure devices for use with a non-return valve; Figures 14 and 15 show an end view of a non-return valve at steps during an alternative method of production; Figures 16 and 17 show an end view of a non-return valve at steps during yet ñrther alternative method of production; and Figures 18 and 19 show an end view of a further alternative non-return valve at steps during a method of production.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Referring firstly to Figure 1, a pipe assembly is indicated generally at 10. The pipe assembly 10 includes a non-return device 12 connected between an inlet pipe 14 and an outlet pipe 16.

The non-return device 12 includes a housing 18 having upper and lower ends 22, 24.

The inlet pipe 14 is associated with the upper end 22 of the housing 18 and the outlet pipe 16 is associated with the lower end 24 of the housing 18. In the present embodiment, the housing 18 defines a tube. In the present embodiment the central region 20 has rigid straight sides. However, in alternative embodiments the central region may have a flexible configuration. The housing 18 includes a location means to locate the valve 26 in the upper end of the housing 18.

A flexible non-return valve 26 is mounted in the housing 18. In general terms, the valve 26 is arranged in the housing 18 so that fluid from the inlet pipe 14 will pass through the valve 26 en route to the outlet pipe 16. As such, the upper end of the valve 26 serves as an inlet 32 through which fluid can enter the valve 26, and the lower end of the valve 26 serves as an outlet 34 through which fluid can exit the valve 26 (as viewed in the orientation of Figure 1).

As can be seen from Figures 1 and 2, the inlet 32 of the valve 26 defines a circular opening 36. A rim 38 is formed at the upper end of the valve 26 and is configured to maintain an open configuration at the inlet 32.

As can be seen clearly in Figure 3, the outlet 34 is defined by opposing wall members 28, 30, which lay flat against one another when the valve 26 is in a relaxed state. The wall members 28, 30 are connected to one another along opposing lateral edges of the outlet 34.

In exemplary embodiments, the wall members 28, 30 define a generally square or rectangular region of the valve 26 (e.g. as can be seen in Figure 13), which would be apparent if the view shown in Figure 1 was rotated through 90 degrees about the longitudinal axis A of the device 10.

The outlet 34 is intended to switch from a closed configuration (e.g. as shown in Figure 3) to an open configuration (e.g. as shown in Figure 4) under the action of fluid entering the inlet 32 of the valve 26. In the open configuration, a central region 42 of the wall members 28, 30 defines a passageway 44 for fluid to flow through an outlet end 46 of the valve 26.

In the present embodiment, the flexible non-return valve 26 is a moulded component, e.g. produced by injection or compression moulding.

As mentioned above, the wall members 28, 30 arc intended to lay flat against each other in the relaxed state. This provides a seal against odours passing up through the valve 26, e.g. from the outlet pipe 16. In order to assist this sealing effect, the valve 26 is fitted with a pair of closure devices, for clamping the wall members 28, 30 together at the lateral edges of the outlet 34.

In the embodiment of Figures 1 to 4, the closure devices take the form of clips 40, which are configured to be a push-fit around the lateral edges of the outlet 34, and thereby clamp the wall members 28, 30 together in the region of the clips 40.

As can be seen in Figure 3 (with the valve 26 in a relaxed state), the wall members 28, are in contact with one another across the width of the outlet 34, which provides a gas tight seal. The clips 40 serve to reduce the risk of a gap arising between the wall members 28, 30 in the region immediately adjacent the lateral edges of the outlet 34, which might otherwise be present due to the moulding process used to form the non-return valve. Hence, the integrity of the sealing performance of the valve 26 is improved.

In the embodiment of Figures 1 to 4, the location of the clips 40 is offset from the outlet end 46 of the wall members 28, 30. The offset means that where the clips 40 actively engage the wall members 28, 30, the clips 40 are bordered by an uncompressed area of the flexible wall material. This has been found to improve retention of the clips 40 (i.e. reducing the risk of clips 40 being displaced during use).

In the present embodiment, the clips 40 are offset from the outlet end 46 by a distance of approximately 2 mm. However, in alternative embodiments the clips may be in line with the outlet end (i.e. no offset) or spaced a greater or lesser distance therefrom.

An example of a clip 40 is shown in more detail in Figure 5. The clip 40 has a U-shaped cross section. The inner sides 50 of the clip are flat to sit flush against the flat outer surface of the respective wall members 28, 30. The clips 40 arc configured to grip onto the valve 26 and compress the wall members 28, 30 together. Hence, the region 52 of the clip 40 into which the edge of the valve outlet is received is narrower than the thickness of the pair of wall members. In the present embodiment, the clips are configured to compress the wall members to 90 % of their wall thickness in the relaxed state.

The clips 40 of Figures 1 to S are made from plastics material (e.g. polypropylene, acetal or nylon). In other embodiments, the clip 40 may be produced from metal. The length of the clips 40 in an axial direction A of the valve is approximately 7.5 mm, but as will be described later, in alternative embodiments the axial length of the clips 40 may be greater than or less than 7.5 mm.

The wall members 28, 30 of the present embodiment are made from silicon rubber, but may alternatively be made from any other elastomer or thermoplastic elastomer.

In the present embodiment, the wall members 28, 30 each have a thickness (feature 54 in Figure 3) that is equal to or greater 3.2 % of the width (feature 56 in Figure 3) of the wall members 28, 30. However, in alternative embodiments the thickness of wall members maybe less than 3.2 %.

A method of producing the flexible non-return valve 26 will now be described with reference to Figures 6 to 8. The flexible non-return valve 26 is formed using standard injection moulding techniques (or alternatively compression moulding techniques), including the use of a mould (not shown) and a core 60 (see Figure 6). In the region of the outlet 34, the mould defines a substantially rectangular section and the core 60 has a substantially rectangular cross section. Accordingly, the wall members 28, 30 are formed in the space between the mould cavities and the core.

Once the valve 26 has been removed from the mould and the core has been removed from the valve 26, the central region 42 of the wall members 28, 30 rest in contact with one another, e.g. due to relaxation or residual stresses (see Figure 7). However, therc may be a tendency for a gap 62 to exist between the wall members 28, 30, on either side of the central region 42 (see Figure 8). To obviate this, the clips 40 are clipped into position, such that when no fluid is flowing from the inlet pipe to the device 10, a gas tight seal is formed across the outlet 34 of the valve 26.

The non-return device 12 provides a reliable and effective solution for preventing waste gases travelling from the outlet pipe 16 to the inlet pipe 14, and can be used for example in household plumbing between a waste pipe and a sink. The closure devices reduce the risk of gaps forming between the wall members 28, 30, and mean that it is possible to produce the valve outlet using a fairly thick, robust core which is less likely to be bent or broken during the moulding process.

Alternative embodiments will now be discussed. Similar features are given similar reference numerals, but different prefixes are added to the reference numerals to distinguish between embodiments.

Figures 9 and 10 show examples of modified clips 140, 240, wherein a mechanical key' is used to further improve retention of the clips 140, 240 on the wall members 128, 130, 228, 230. In the example shown in Figure 9, a nib 164 is moulded on the wall members 128, 130, and the clip 140 includes a slot 166 that positively engages the nib 164. In the example shown in Figure 10, the wall members 128, 130 are moulded to define an angled section 264 at the lateral edges of the outlet, and the clip 240 includes a complementary angled portion 266 that engages with the angled section 264.

Referring to Figures 11 to 12, an alternative closure device 340 is dimensioned to be a loose fit over the wall members 328, 330. A force F is then applied to the closure device 340 to crimp the closure device 340 in place, and thereby apply a compressive force to the wall members 328, 330. The closure device 340 is made from metal, but it may also bc made from plastic.

Tn a further alternative embodiment, the closure device may be dimensioned to be a close fit to the wall members (i.e. so as to apply little or no compression to the wall members), and an adhesive andior mechanical key mechanism may be used to locate the closure device on the wall members.

Referring to Figure 13, clips 440, 540 having different axial lengths are illustrated.

For example, the clip 440 only extends part of the length of the outlet portion, as previously described, whereas the clip 540 extends substantially the entire length of the outlet portion. Any practical length of clip can be used up to the maximum length of the outlet portion, but it has been found that a length of between 6 and 10 mm in length, for example 7 to 8 mm, gives good performance.

In further alternative embodiments, instead of using a closure device, adhesive or welding may be used to prevent the generation of undesired gaps between the wall members 28, 30 along the lateral sides of the outlet when the device is use. Referring to Figures 14 and 15, an adhesive 667 is applied at a lateral edge region 662 where such gaps might have a tendency to develop, or where a gap has been generated during the moulding process (e.g. as a result of the wall member or core thickness).

The wall members 628, 630 are then clamped together by a force C, and once the adhesive has set or cured, the clamp is removed. In thc present embodiment, the flexible non-return valve is made from silicon rubber, and the adhesive is cyanoacrylate contact adhesive, but other suitable adhesives may be used.

Referring to Figures 16 to 17, the wall members 728, 730 are pressed between an ultrasonic welding horn 768 and a metal platten 770, for forming a weld 772 between the wall members at a lateral edge region 762.

Referring to Figures 18 and 19, the wall members 828, 830 may be produced with a convex profile, so as to curve towards one another in a central region. To form such a profile, a core having a concave profile can be used. Both wall members are convex, but in alternative embodiments only one wall member may be convex. Forming such a profile further biases the wall members 828, 830 together in the central region, which can enhance the sealing performance. Larger gaps 862 might typically be formed as a result (i.e. in the moulding stage), but these can be closed using clips 840, or any other alternative closure device.

Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

In the present embodiment the rim is configured to support the wall members apart to form the opening, but in alternative embodiments an alternative means may be used to define the opening. *11