PIPE COUPLING

The present invention relates to a pipe coupling.

It is often necessary to carry out a repair, alteration or replacement within a run of pipe. Several conventional methods and pipe couplings are known for filling a gap in pipe-work with a length of pipe.

Complications and problems arise when it is impossible or undesirable to draw together or move the pipe ends requiring coupling. It may be difficult to obtain or make the exact length of pipe coupling required.

Fitting the pipe coupling may be difficult without moving the pipe ends.

Damage may occur when trying to force the pipe coupling onto the pipe ends. Multiple components may be required - for example a section of pipe of shorter length than the gap to be filled may be joined to each of the pipe ends by rubber sleeves - thereby complicating the fitting process, increasing cost and leading to several potentially weak points which may be susceptible to leakage.

In a first aspect the present invention provides a pipe coupling comprising:- a) a first coupling section; and, b) a second coupling section, whereby, in use, the first and second coupling sections are co-joined and placed between opposed ends of a pipe to be coupled whereupon the first and second coupling sections are moved axially with respect one to the other to engage with respective ones of the opposed ends of the pipe, wherein the coupling sections each comprise a locking portion to facilitate, in use, mutual engagement between the respective locking portions and locking of the pipe coupling in place between the opposed ends of the pipe as aforesaid,

characterized in that the locking portion of the first coupling section is provided by a series of annular ribs extending part way about a peripheral external wall of the first coupling section and the locking portion of the second coupling section is provided by a series of annular grooves extending part way about an internal peripheral wall of the second coupling section for receiving, in use, the annular ribs of the first coupling section.

The ribs and grooves inter-engage to lock the first and second coupling sections to each other. At their point of joining, the first coupling section is of narrower diameter than the second coupling section so that the first coupling section, when not in a locked position, is moveable telescopically with respect to the second coupling section. The presence of several ribs and grooves means that the first and second coupling sections can be locked together to form a pipe coupling of variable length. Thus a single product can conveniently be used to act as a conduit for a range of gap lengths, thereby enabling a cost- and time- effective solution.

The product is usable in a confined space and is compatible with little or no pipe movement either vertically or horizontally.

ft is possible for the annular ribs to extend about the peripheral wall for approximately 90 degrees on opposite sides thereof and the annular grooves to extend about the internal peripheral wall for approximately 90 degrees at opposite sides thereof to facilitate, in use. co-joining of the first and second sections one with the other and locking of the pipe coupling in place as aforesaid. The extent of the ribs and/or grooves may of course be different to 90 degrees. For example, the extent of the ribs and/or grooves may be less than 90 degrees. It is merely required that there are sufficient projections and indentations for the first and second

coupling sections to be held together (or "locked") lengthwise. The rib segments may be discontinuous or toothed rather than continuous.

Preferably, when the pipe coupling is in use, locking of the pipe coupling in place between the opposed ends of a pipe is achieved by relative rotation of the coupling sections one with respect to the other whereby the annular ribs are accommodated within the annular grooves.

Thus it is possible to move the coupling sections longitudinally with respect to each other when they are in one orientation, and subsequently rotate one with respect to the other in order to prevent further lengthwise movement.

The process may be reversible; in other words, starting from the "locked" state, the coupling sections may be rotated with respect to each other in order to allow longitudinal movement, i.e. in order to "unlock" the pipe coupling. This allows the pipe coupling to be demountable, i.e. removable from the pipe ends, assuming that the method of attachment to the pipe ends is also reversible. The demountable design is a versatile product which may be interchanged easily, as may be required when fitting a temporary pipe coupling. Alternatively, the locking of the pipe coupling in place by rotation may be effectively irreversible: this provides extra security and helps prevent accidental decoupling or leakage.

The annular ribs and the annular grooves may extend about their respective peripheral walls in a plane at 90 degrees to a longitudinal axis of the pipe coupling or substantially so. In this scenario, a minor rotation whilst the ribs and grooves are inter-engaged will result in the coupling sections maintaining a fixed longitudinal position with respect to each other.

Alternatively, the annular ribs and the annular grooves may extend helically about their respective peripheral walls. The ribs and grooves still extend only part of the way around the walls (i.e. the ribs and grooves are discontinuously helical), so that quick longitudinal telescopic adjustment is possible, followed by rotation to inter-engage the first and second coupling sections. When the annular ribs and the annular grooves extend helically about their respective peripheral walls, this has the advantage that, rather than the coupling sections being lockable with respect to each other in a series of longitudinal discrete steps, each inter- engaged state is such that minor rotation can increase or decrease the overall length of the locked pipe coupling. This continuous rather than discrete locking facility enables the pipe coupling to precisely fit any gap length.

The first coupling section may comprise an upstream sleeve for accommodating, in use, an end portion of an upstream one of the opposed ends of a pipe to be coupled.

The second coupling section may comprise a downstream sleeve for accommodating, in use, an end portion of a downstream one of the opposed ends of a pipe to be coupled.

Alternatively, the first and second coupling sections may respectively comprise downstream and upstream sleeves.

Additionally or alternatively either or both of the coupling sections may also comprise an internal flange so that the pipe end fits like a sleeve over the coupling section.

The pipe coupling may comprise any suitable material including plastic, copper, brass and aluminium. The material depends on the application and of course the pipe coupling must be fit for the same purpose as the pipes with which is to be coupled. For example, the first and second coupling sections may be moulded from a suitable plastic composition commensurate with achieving durability and strength for purpose.

The pipe coupling may be used in several applications in the plumbing, drainage and building industries, amongst others. Other markets include the petrochemical industry, brewery compressed air lines, and hydraulic ducting. The pipe coupling is useful in domestic and commercial plumbing and drainage scenarios, in central heating systems, kitchen installations, bathroom installations, the solution of plumbing problems, and the adaptation of fittings when new products are installed.

Particular areas where the product is useful include: above ground drainage including "grey" waste, soil waste and rainwater; below ground drainage; hot and cold water supply in both gravity driven and pressurised systems; central heating; and gas pipe supply.

For example, when a WC is relocated, this may alter the fall of the waste pipe into the Y boss of the soil stack, thereby necessitating a pipe coupling. Similarly, relocation of other items such as showers, baths or basins may result in gaps which require a pipe coupling.

In another example, it may be necessary to unblock or replace a pipe within a fixed run of solvent weld or copper piping. For example, where there is a fixed run of pipes for public toilets, there may be a blockage, for example, between two of several urinals. The present invention allows the blocked section to be removed and replaced in a cost-effective way, rather than removing the urinals.

The pipe coupling may be used horizontally or vertically, or indeed in any orientation.

The pipe coupling may simply act as a conduit, or it may have additional features. For example, it may comprise an additional outlet or inlet or other feature. Thus, the pipe coupling may for example comprise a T branch, Y branch, multi boss, roding plate, isolator, stopcock valve, variable angle soil or drainage connector, radiator tail, tap connector, branch connector or pipe extension.

The pipe connector can be used to repair burst pipes within floor joist voids, or similarly a damaged drain below-ground. The use of functionalized pipe coupling enables the addition of further branches to existing pipe work, for example pipe work which is buried underground. The pipe connector is also useful in other confined spaces, for example where it is necessary to replace a stopcock where the pipes are located at the back of a hot water storage tank and are for example strapped onto a pipe board.

Whilst the method of locking the coupling sections to each other according to the present invention requires rib and groove segments as described above, the attachment of the coupling sections to the pipe ends themselves can be facilitated in a variety of ways. One alternative comprises the use of compression joints between the pipe connector and the pipe ends; for example each or both coupling section may carry an external thread onto which may screw a nut residing on the pipe end, whereby a seal is effected through use of an olive between the pipe and the coupling section. Another alternative may require the pipe connector to be welded to the pipe ends. A further alternative comprises the use of so-called "push-fit" ends on the coupling sections to enable them to be

simply pushed onto and seal with the pipe ends by means of teeth and seals. Yet another alternative comprises the use of so-called "demountable quick fit" ends on the coupling sections; these are effectively removable ''push-fit" fittings. Many other alternatives and examples are possible and any known fitting can be used for the attachment of the coupling sections to the pipe ends.

The product is suitable for use with pipes of any diameter, and the diameter, size and composition of the coupling sections are chosen accordingly. The product is particularly useful in pipe sizes of 8 mm to 316 mm. The product is however suitable for pipe sizes outside these ranges

The length of the pipe coupling is not particularly limited, and the skilled person is aware of the sizes that are useful in practice. In one specific example, a pipe connector when expanded in use in a soil pipe may be approximately 450 mm in length.

The present invention will now be described by way of non-limiting example only and with reference to the accompanying drawings in which:-

Figure 1 shows in partial cut-away view a pipe coupling according to one embodiment of the present invention;

Figure 2 shows in transverse cross-sectional view the first coupling section of the pipe coupling shown in Figure 1 ;

Figure 3 shows in transverse cross-sectional view the second coupling section of the pipe coupling shown in Figure 1 ; and

Figures 4a to 4e show other embodiments of the pipe coupling of the present invention.

With particular reference to Figure 1 , the invention provides a pipe coupling (2) for use in coupling opposed pipe ends (8, 10) of a waste water pipe (12). the pipe coupling (2) comprising first and second coupling sections (4, 16) that are co-joined and placed between the opposed ends (8. 10) whereupon locking of the pipe coupling (2) is effected to couple the pipe ends (8, 10) together.

The first and second coupling sections (4, 16) include ribs (18) and grooves (26) respectively that inter-engage upon rotation of the first and second coupling sections (4, 16) to lock the sections together and to lock the pipe coupling (2) in place. The ribs (18) and grooves (26) are shown in cross-section in Figures 2 and 3.

Appropriate seals (24, 34, 42) are provided in the coupling sections (4, 16) to prevent leakage therefrom.

The pipe coupling (2) is adapted for use both vertical and horizontal orientations in manifold applications some examples of which are shown in Figures 4a to 4e. These show, respectively: a joint with a T branch; a joint with a T branch and stop cock; a joint with a Y branch; a joint with a multi boss; and a joint with a roding plate.

The pipe coupling sections (4, 16) may be moulded from a plastics composition; alternatively, other materials may be used for making the sections.