Field of Invention

The following invention relates to the fields of pipes and pipe couplings. More specifically, the invention relates to transportation and testing caps for pipes and pipe couplings.

Background

Approved Document H of the Building Regulations 2010 sets out the requirements for drainage systems in construction works within the UK. As part of the regulations, it is required that waste plumbing for domestic and non-domestic buildings pass an air tightness test. As of 2015, the regulations require that the pipe fittings and joints of a sanitary pipework system should be capable of withstanding an air test of positive pressure of at least 38mm water gauge (approx. 373 Pa) for at least 3 minutes.

Commonly, soil stacks are assembled on site from pipes, bends, couplings and branched sections, depending on the requirements of the drain-waste-vent system. Air testing of the assembled soil stack requires the soil stack to be plugged at each end and at any branches along the length of the pipe system. This process can be slow and laborious, and requires the use of specially designed and relatively expensive plugs. Typical plugs for such applications comprise a flexible gasket which can be expanded to seal against the inside surface of the pipe. This testing process is carried out once installed to ensure that gas from the sewers is not vented into the building.

There is a growing market for preassembled soil stacks in order to reduce the installation time and labour costs on site. In order to ensure the quality of the preassembled soil stacks, the soil stacks are air tested prior to shipping to ensure they conform to the necessary regulations. Once the soil stack is installed, building contractors will then carry out a second air test to comply with regulations and ensure the installation is fault free. During shipping, the pre-assembled soil stacks are fitted with cover caps over any pipe couplings to minimise dirt ingress and damage to the pipe couplings which could compromise the quality of the seals with the rest of the plumbing system. It is thus desired to provide a pipe cap which mitigates or ameliorates some of the above problems.

Summary of Invention

According to the invention, there is provided a cap for a pipe or pipe coupling. The cap may comprise a plug portion insertable into an open end of a pipe or pipe coupling. The cap may comprise a lip extending from the plug portion. The cap may comprise a securing means for securing the cap in position.

The plug portion may comprise a cylindrical wall extending from the lip and a base portion closing an end of the cylindrical wall. In some embodiments, the wall may be frusto-conical. In some embodiments, the wall may have a cylindrical portion and/or a frusto-conical portion. In some embodiments, the wall may have a curved profile.

The base portion may be provided at the opposite end of the cylindrical wall, relative to the lip. In use, the base portion may be receivable within an open end of a pipe or pipe coupling.

The cylindrical wall may be rigid. In some embodiments, the cylindrical wall may be resilient and/or deformable. Resilient and/or deformable walls con be configured to provide better seals against pipe connectors, but may have a shorter product lifespan.

The plug portion may comprise a tapered surface. The tapered surface may be located between the cylindrical wall and the base portion. The tapered surface may be configured so as to narrow toward the base portion.

The lip may extend around the all or part of the perimeter of the plug portion. Preferably, the lip extends around the circumference of the plug portion.

The lip may extend perpendicularly from the plug portion. The lip may extend perpendicularly to the central axis of the plug portion. The lip may extend perpendicularly to the axis of a pipe or pipe connector to which the cap is to be fitted. The lip may comprise an annular surface for abutting an end of a pipe or pipe coupling. The lip may be configured to extend across the thickness of the walls of pipe or pipe coupling to which it is to be fitted.

The securing means comprises at least one arm extending from the lip. The at least one arm may be configured to extend around the exterior of a pipe or pipe coupling. The at least one arm may be curved, for example, around the same axis as the plug portion.

In some embodiments, the securing means comprises at least two arms extending from the lip. The at least two arms may be configured to extend around the exterior of a pipe or pipe coupling. The at least two arms may be curved, for example, around the same axis as the plug portion. The at least two arms may be provided on opposite sides of the plug portion.

The arm or arms may comprise a hook portion. The hook portion may be configured to engage a cooperating formation on a pipe or pipe connector. The hook may be configured to resist removal of the cap when the hook is engaged with the cooperating formation. The hook may be provided with an angled face. The angled face may be configured to apply an outward force to the at least one arm. The angled face may be configured to allow the hook portion to ride over the cooperating formation.

The arm or arms may be resiliently flexible and/or resiliently biased.

The lip may comprise at least one aperture therethrough adjacent to the at least one arm. The or each aperture may be arcuate. The or each aperture may have a width equal to the width of the at least one arm.

The securing means may comprise a plurality of arms spaced circumferentially around the lip. In some embodiments, the securing means comprises three or more arms extending from the lip. In embodiments comprising more than one arm, the arms may be spaced equidistantly around the perimeter of the lip. The lip may comprise an aperture therethrough adjacent to each of the arms. In embodiments comprising more than one arm, the plurality of arms may comprise at least one first arm with a first length and at least one second arm with a second length, greater than the first. Optionally, a third arm with a length greater than the first and second may be provided.

The cap may be formed from polypropylene. The cap may be moulded, for example injection moulded.

Brief Description of the Drawings

Embodiments of the invention will now be described with reference to the following figures, in which:

Figure 1a is a perspective view of a cap installed in a pipe or pipe coupling; Figure 1b is a cross-section through the plane A-A of Figure 1a;

Figures 2a to 2c are perspective, top and side views respectively of a cap for a pipe or pipe coupling;

Figure 2d is a perspective view of the cap of Figures 2a to 2c installed in a pipe connector;

Figure 2e is a cross-section through the plane B-B of Figure 2d;

Figure 3a and 3b are perspective and side views of an embodiment of pipe cap; Figures 3c is a perspective view of a cap installed in a pipe connector;

Figure 3d is a cross-section through the plane C-C of Figure 3c; and Figures 4a to 4c are plan, perspective and side views of a further embodiment of pipe cap.

Specific Description

Turning now to Figures 1a and 1b, there is shown a conventional transport cap 1 installed in a pipe or pipe coupling 2.

The cap 1 comprises a plug portion 11 and a lip 12 configured to prevent the plug portion from being inserted too far into the pipe coupling 2. The cap 1 is fitted to the pipe or pipe coupling 2 prior to transport so as to prevent damage during transit, especially to a flexible gasket 21 provided adjacent to the mouth of the pipe coupling 2. The cap 1 is of a simple push fit design and is retained by a friction fit with the inner surface of the pipe coupling 2 and the flexible gasket 21. During installation of the pipe coupling (whether as part of a pre-assembled soil stack or as a discrete component), the user can easily pull the cap 1 out of the pipe coupling 2 so as to connect the coupling to a pipe (not shown). During air testing procedures, the cap 1 is replaced with a more secure cap for sealing the pipe or pipe coupling 2.

Turning now to Figures 2a to 2c, there is shown a first embodiment of cap 100 for a pipe or pipe coupling according to the invention. The cap 100 is formed from a plug portion 110, lip 120 and securing means 130.

The plug portion 110 is generally cylindrical and formed from a wall portion 111, a tapered portion 113 and a base portion 115. The wall portion 111 is substantially cylindrical e.g. it may be provided with a small taper to aid de-moulding and/or location of the plug portion within a pipe or pipe coupling. The tapered portion 113 extends from the cylindrical wall 111 and narrows toward the base portion 115, which extends perpendicularly relative to the cylindrical wall 111. The tapered portion 115 is thus a small portion with a frusto-conical shape and an angled outer surface to assist with the location of the plug portion 110 within a pipe or pipe coupling (not shown). The plug portion 110 may be hollow. The end of the plug portion 110 opposite to the base portion 115 is open, thus defining an approximate U-shaped cross-section. The plug portion 110 is sized so as to be insertable within an open pipe or pipe coupling.

The lip 120 is an annular surface which extends radially from the plug portion 110. As shown in Figure 2c, the lip 120 extends perpendicularly from the cylindrical wall 111. The lip extends around the full circumference of the plug portion 110. The width of the lip 120 is designed to span the wall thickness of a pipe or pipe coupling with which the cap 100 is intended for use. The upper surface 121 of the lip 120 is flat, and can be provided with markings such as logos and/or branding or for other product information such as recycling information (not shown).

In Figures 2a to 2c, the securing means 130 comprise three arms 131. The arms 131 extend perpendicularly from the lip 120 and coaxially with (or parallel to) the plug portion 110. As shown in Figure 2b, each arm 131 has an arcuate cross-section when viewed from above (i.e. axially of the cap 100). The arms 131 are integrally formed with the lip 120, with the outer surface of the arms 131 extending continuously from the outer perimeter of the lip 120. The arms 131 are connected to the lip 120 at a first end and are joined by a curved corner 133 on either side of the arm 131. Adjacent to each of the arms 131, the lip 120 is provided with an aperture 123 extending through the thickness of the lip 120. The apertures 123 are arcuate and extend parallel to the arms 131 (i.e. the apertures 123 and the arms 131 are concentric). In the embodiment shown, the apertures 123 are approximately the same width as the arms 131. The apertures 123 are sized and positioned to reduce the rigidity of the arms 131 and allow a degree of flexibility, so that the head 135 of the arms 131 can flex outwardly i.e. away from the plug portion 110 as shown by the arrow X in Figure 2c. The curved corners 133 help to evenly distribute the internal stresses caused by flexing the arms 131 and serve to reinforce the connections between the arms 131 and the lip 120, since the positioning of the apertures 123 means the arms 131 are connected to the lip 120 only at each side. The head 135 of the arms 131 is provided with a hook portion 137. The hook portion projects perpendicularly from the arm 131. The hook portion 137 projects in the inwardly radial direction i.e. toward the plug portion 110. The hook portions 137 are configured to engage cooperating formations on a pipe or pipe coupling (not shown). The heads 135 have an angled face 139 thereon. The angled face 139 is configured so that the arms 131 are driven outwards when the angled face 139 contacts a cooperating formation on a pipe or pipe coupling as described below.

The cap 100 is formed from moulded plastic as a single integral component. Polypropylene is preferred, since it has the mechanical properties required to have both a sufficiently rigid plug portion and flexible arms 131. In alternative embodiments (not shown), the cap 100 could be formed from any other suitable plastic. In some embodiments (not shown), the cap may be formed from a composite or laminate material. For example, the cap may be formed from a fibre reinforced plastic, such as GRP. Alternatively, the cap may be formed from a coated cardboard material, such as a plastic coated cardboard.

Turning now to Figures 2d and 2e, there is shown the cap 100 when installed on a pipe coupling 200. The coupling 200 is a conventional expansion coupling for connecting to a pipe. The expansion coupling 200 is a straight tube which can be welded to further pipes at a first end, and which comprises a connection means at a second end. The connection means comprises a ridge 205 formed in the outer surface of the tube. The ridge 205 extends radially around the complete perimeter of the tube. The ridge 205 projects away from the tube e.g. in the radial direction.

The ridge 205 defines a recess 203 which extends circumferentially around the inner surface of the tube. The recess 203 retains a gasket 201. The gasket 201 is a flexible ring seal which provides a fluid-tight seal against the outer surface of a pipe (not shown) inserted into the coupling 200 in use.

When fitted to the coupling 200, the plug portion 110 of the cap 100 is received within the mouth of the coupling 200 and seals against the gasket 201. It is important that the plug portion is sufficiently rigid that the seal between the plug portion and the gasket 201 is strong enough to withstand the positive pressure of an air test without leaking.

When the cap 100 is seated, the lip 120 abuts the end of the coupling 200. The arms 131 of the securing means 130 extend parallel to the coupling 200. As the cap is being positioned, the angled faces 139 of the arms 131 contact a deflecting face 209 of the ridge 205, which deflect the arms 131 outwards and over the ridge 205. Once the heads 135 of the arms pass over the ridge 205, the resilience of the arms means they snap back into position with the hook portion 137 hooking over and engaging a shoulder 207 on the ridge 205. The resilience of the arms 131 thus retains the hooks portions 137 engaged with the shoulder 207. Thus, in the default state, the securing means 130 prevent removal of the cap 100 from the coupling 200 unless the arms 131 are manually flexed outwards by a user.

Manual removal of the cap 100 is relatively easy for a user, who simply flexes the arms 131 of the retaining means outwards to disengage the hook portions 137 and the shoulder 207, and pulls the cap out of the pipe coupling 200. However, the securing means 130 is sufficiently strong to prevent the cap 100 from being pushed out of the coupling by a positive pressure during an air test. During an air test, the plug portion is sealed to the coupling 200 by the gasket (and thus air will not leak around the plug portion during test conditions). The positive air pressure during a test applies a force to the base 115 of the cap 100 to push the cap out of the coupling 200. However, the force is withstood by the hook portions 137 of the arms 131 which engage the shoulder 207. As noted previously, a suitable material for the cap is polypropylene, since it is sufficiently strong to resist deformation during an air test, but still resiliently flexible to allow for easy installation/removal of the cap 100.

Turning now to Figures 3a to 3d there is shown a further embodiment of the invention. Figures 3a and 3b show a cap 300 for a pipe or pipe coupling 400, which is substantially the same as the cap 100 and for which like features will not be re described.

The cap 100 is configured to fit a much larger diameter pipe or pipe coupling 400 compared to the pipe coupling 200 described previously. The plug portion 310 is thus much wider than the plug portion 110 of Figures 2a-2e. The plug portion 310 comprises a tapered portion 313 of approximately the same depth and angle as the tapered portion 113. However, due to the overall increase in size, the tapered portion 313 forms a smaller proportion of the plug portion 310. As shown in Figures 3c and 3d, the plug portion 310 is thus configured to closely conform to the inner profile and dimensions of the larger pipe coupling 400.

Similarly, the lip 320 and securing means 330 are increased in size to accommodate the larger exterior profile and dimensions of the pipe coupling 400. In particular, the apertures 323 are wider (i.e. extend through a longer arc) than the adjacent arms 331. Because the arms 331 are wider than the arms 131 of the smaller cap, they would be much more rigid and less flexible than the smaller arms 131. Thus, the relative size of the apertures 323 is increased in order to weaken the arms, and thus configure the flexible resilience of the arms 331. In alternative embodiments, the relative sizes of the arms and apertures can be modified to ensure that the arms are sufficiently strong and resiliently flexible so as to allow simple installation and removal of the cap, while providing the necessary strength during air testing.

Overall, the cap 300 is taller than the cap 100. In other words, the wall portion 311 is taller than the wall portion 111, and the arms 331 are longer than arms 131. In Figure 3b, the arms 331 appear to not extend as far down the wall portion 311 compared to the smaller cap 100, however this is due to increased height of the cap 300. The increased height is configured to fit with the dimensions of the pipe coupling 400 and the relative size and position of the ridge 305. Turning now to Figures 4a to 4c, there is shown a further embodiment of the invention. The cap 500 is substantially the same as caps 100, 300, and like features will not be re-described. The cap 500 differs in that it has two sizes of arms 531, 532. The arms 531 are shorter than arms 532 and thus the cap 500 can be fit to two different sizes of pipe or pipe connector which have different configurations of ridge to which the arms 531, 532 can connect. For pipe connectors with longer and/or larger ridges, the longer arms 532 can hook over the ridge and retain the cap 500 in situ. Since the arms 531 cannot hook over the ridge, they are simply flexed outwards and sit on, but do not engage, the ridge. Similarly, for pipe connectors with smaller or shorter ridge configurations, the longer arms 532 are superfluous but the arms 531 are able to engage the ridge and secure the cap 500. The two types of arms 531 and 532 are arranged in an alternating pattern around the plug portion. The upper surface 521 of the lip 520 is provided with a manufacturers logo 522 to provide information to the user. This surface may be used to provide details on the cap 500 such as material, product size, pressure ratings, recycling information etc. In some embodiments (not shown) the upper surface may also be provided with logos or other information on the upper surfaces 121, 321.

The cap can be formed in a range of sizes in order to form a good fit with a range of different pipe sizes.