FIELD OF THE INVENTION

The present invention relates to push-fit pipefittings for non-pressurised applications. In particular, the present invention relates to a push-fit pipefitting for wastewater applications, for example greywater.

BACKGROUND

Typically, acrylonitrile butadiene (ABS) and polyvinyl chloride (PVC) pipefitting joints, when used for wastewater/greywater applications, are glued/cemented together to create a watertight seal at the joint.

An alternative joint arrangement is using compression fittings. A compression fitting does not require glues or cements. In general, these fittings are made up a compression unit body (incorporating an external thread), a tapered rubber seal, a plastic washer and a screw cap/internally threaded nut. These parts are attached to each other by first sliding the nut onto a free end of a pipe and then connecting the plastic washer and the rubber seal. The body is attached by inserting the end of the pipe into a collar on one end of the body, pushing the washer into contact with the rubber seal and then screwing the cap/nut onto the body. Screwing/tightening the nut and body compresses the rubber seal to provide a seal between the pipe and the body of the compression fitting.

There are disadvantages to using glued/cemented joints, for example during installation curing/setting time must be factored into the time for installation, post installation repairs require the joint to be cut and replaced often with multiple joints. Typically, a period of 24 hours is allowed for the glue/cement to cure completely before testing water tightness of the joint. It will be appreciated; the properties of ABS and PVC are different. Therefore, the installer requires in his toolkit different glue/cement components for each, and often different preparatory cleaners are also required.

A disadvantage of compression fittings is that they are prone to wear and tear and the watertight/leak-free properties can fail over time. Another disadvantage of a compression fitting is that it can be over or under tightened, over or under tightening can affect water tightness of the joint that is created by using the fitting. If overtightened, it is possible the rubber seal could be damaged or distorted such that an efficient seal is not provided. Another disadvantage of a compression fitting is that they tend to be big and bulky which makes them unsuitable for use in confined spaces.

Joints that are glued/cemented are designed to keep pipes in place and restrain movement to keep the connections/joints watertight and leak-free. Compression joints should be used where movement is not expected and where space is available to include a compression fitting.

SUMMARY OF INVENTION

The present invention provides A push-fit pipefitting for wastewater applications, wherein the push-fit pipefitting comprises: a tubular body; a metal castellated ring; and a ring seal member; wherein the tubular body includes an internal stepped profile at each end, wherein the stepped profile provides a seat upon which a perimeter of the castellated ring is received and wherein the perimeter of the castellated ring is sandwiched between the seat and a face of the ring seal member; wherein the tubular body includes a radially projecting inner rib providing a limiter, which limits insertion of a section of pipe into the tubular body; and wherein a deformable seal of the ring seal member and castellations of the castellated ring are operable, in use, to deform and engage with an external wall of an end portion of a pipe being pushed into the pipefitting, wherein the castellations are operable to elastically deflect and grip the external wall of the end portion of the pipe and the deformable seal is operable to sealingly engage with the external wall of the end portion of the pipe to provide a watertight joint between the pipe (18) and the pipefitting, wherein the ring seal member and the castellated ring are arranged such that, in use, the end portion of the pipe engages first with the deformable seal, followed by the castellated ring and finally the radially extending rib.

The castellated ring may be made of stainless steel.

The castellated ring may include an external perimeter ring and radially projecting castellations. Each castellation may be inclined relative to the perimeter ring. The incline may be in the region of 45 to 60 degrees.

The angle of incline is selected as an angle suitable to allow elastic deformation of the castellations upon insertion of a pipe-section into the pipefitting such that the castellations deform and grip the outer wall of the pipe-section as it is inserted into the pipefitting.

The castellations may be oriented in the tubular body such that the incline is towards the inside of the tubular body i.e. sloping away from the end via which the castellated ring is inserted into the tubular body.

The direction of the incline/slope, the arrangement of the castellations and the material of the castellated ring is such that when a section of pipe is inserted into the pipefitting the castellations will each deform elastically and the free ends of the castellations will engage/grab the external wall of the pipe section to provide a secure assembly of the pipe and pipefitting. It will be appreciated the function of the castellations is like barbs/spikes.

The castellations may be uniformly circumferentially spaced. Alternatively, the castellations may be arranged in diametrically opposed clusters. For example, three clusters may be provided such that

A head of each castellation may be provided by a substantially square profile. Alternatively, the head of each castellation may be curved, triangular etc.

The ring seal may be defined by a tapered/sloping surface, wherein the sloping surface slopes towards the centre of the tubular body i.e. sloping away from the end via which the castellated ring is inserted into the tubular body.

The ring seal may be configured as part of a unitary ring seal member, wherein the ring seal member includes at least a double wall structure, comprising an external wall, which defines the body of the ring seal member and an internal wall, wherein the internal wall defines the ring seal.

The internal wall/integral ring seal may include one end attached to the body and a free end, wherein the ring seal extends longitudinally from the attached end. The integral ring seal may include a tapered/sloping surface, wherein the tapered/sloping surface slopes towards the inside of the tubular body i.e. sloping away from the end via which the castellated ring is inserted into the tubular body

The free end of the integral ring seal may be displaced from an internal surface of the body of the ring seal member and from a second end of the body of the ring seal member. A ring seal, separate or integral, is configured to deform and engage with the external wall of a pipe-section as it is inserted into the push-fit pipefitting. The ring seal facilitates sealing engagement of the pipefitting with the external surface of the pipe.

The ring seal and ring seal member may be made of synthetic rubber such that ring seal is operable to sealingly engage with a pipe inserted in the pipefitting.

External dimensions of the ring seal member may correspond substantially with internal dimensions of receiving ends of the tubular body.

The pipefitting may include collars operable to be connected to each end of the tubular body such that longitudinal displacement of the castellated ring and ring seal member is prevented. Connection of the collars and the tubular body may be by threaded connection. Alternatively, or in addition, connection of the collars and the tubular body may be by solvent welding, gluing, cement etc.

The radially extending rib may be located substantially mid-length of the tubular body.

An embodiment of the present invention is described below, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 A illustrates an exploded view of a push-fit pipefitting;

Fig.l B illustrates a section of a castellated ring to illustrate the incline of the castellations relative to the perimeter ring;

Fig. 2 illustrates an assembled push-fit pipefitting comprising the components illustrated in Fig. 1 ; Fig. 3 illustrates an assembled push-fit pipefitting comprising the components illustrated in Fig. 1 and an end portion of a pipe inserted in one end; and

Fig. 4 illustrates a cross-section view of the assembled push-fit pipefitting as illustrated in Fig. 2.

DESCRIPTION

Fig. 1 to 4 represent a push-fit pipefitting 10, which is suitable for non-pressurised applications, for example wastewater/greywater applications.

The push-fit pipefitting 10 includes a tubular body 12, two castellated rings 14, two ring seal members 15 and two retaining end caps/collars 16.

Fig. 2 and Fig. 3 represent the assembled pipefitting 10, where Fig. 4 shows a pipe 18 extending from one end 20 of the pipefitting 10.

It will be appreciated the pipefitting 10 is configured to receive a pipe in both ends 20, 22 of the tubular body 12, but for illustrative purposes only one pipe 18 is illustrated.

Fig. 4 represents a section drawing of the assembled components of the pipefitting 10 and makes visible the internal and external configuration of the tubular body 12, the castellated rings 14, the ring seal members 15 and the end caps/collars 16.

The tubular body 12 is made of plastic material, for example acrylonitrile butadiene (ABS), polyvinyl chloride (PVC) etc.

The internal surface 24 of the tubular body 12 includes a stepped profile 26 proximate each end. The stepped profile 26 is configured to provide a seat for the castellated ring 14 and the ring seal member 15. The internal surface 24 also includes an internal rib 28, which radially projects from the internal wall/surface 24 of the tubular body 12. The rib 28 is located approximately mid-length of the tubular body 12. The rib 28 provides a stop, which limits how far a pipe 18 can extend into the tubular body 12 from each open end 20, 22 of the pipefitting 10. It will be appreciated, the location of the rib 28, relative to the ends 20, 22 of the pipefitting 10, is evident to an installer and therefore during installation the installer can be sure the pipe 18 is fully inserted.

In the illustrated example, the external surface 30 of the tubular body 12 includes a threaded section 32, which corresponds with internal threads 34 on the end caps/collars 16. The configuration of the external surface 30 and the end caps/collars 16 is such that when screwed together each cap 16 retains the castellated ring 14 and the ring seal member 15 within the tubular body 12 between the step/seat 26 and the inner face of the end cap/collar 16 such that longitudinal movement of the castellated ring 14 and ring seal member 15 is prevented.

It will be appreciated that threaded engagement is one example of how the end caps 16 are secured to the tubular body 12. Other arrangements are possible, for example bonding/cementing the mating surfaces of the external surface 32 of the tubular body 12 and the internal surface of the cap 16. It will be appreciated the function of the caps 16 is to retain the castellated ring 14 and the ring seal member 15 within the tubular body 12.

In the illustrated example, the cap 16 is made from the same or similar plastic material from which the tubular body 12 is made.

In the illustrated example, the castellated ring 12 is made from stainless steel. It will be appreciated that other metals are suitable, but due to the application in wastewater/greywater pipe systems it will be appreciated that rust proof materials are preferred such that longevity of the pipefitting 10 is ensured.

The castellated ring 42, includes an external perimeter ring 40 and radially projecting castellations 42. In the illustrated example, the castellations 42 are each separated by similar shaped indentations 43 to define a castellated profile. In the illustrated example, the castellations 42 and indentations 43 are uniformly shaped and spaced around the circumference of the perimeter ring 40. Each castellation 42 is substantially square and projects from an internal edge 44 of the perimeter ring 40; the internal edge 44 defines the root of each castellation 42.

It will be appreciated, some uniformity of the castellations is desired to ensure stable support of a pipe within the pipefitting 10. Other arrangements such as clusters of castellations distributed around the perimeter or a triangular distribution may provide suitable/stable support.

The shape and form of the head/tip 41 of each castellation may be substantially square (as illustrated). Alternatively, the head/tip 41 of each castellation may be curved or pointed etc.

Referring to Fig. 1A, Fig. 1 B, Fig. 2 and Fig. 4, each castellation 42 is inclined relative to the perimeter ring 40. The castellations 42 each slope from their root 44. In the illustrated example the slope/incline 45 is in the region of 45 to 60 degrees. It will be appreciated, the angle of incline 45 is selected as an angle suitable to allow elastic deformation of the castellations 42 upon insertion of a pipe-section 18 into the pipefitting 10 such that the castellations 42 deform and grip the outer wall of the pipe-section as it is inserted into the pipefitting 10. In the assembled push-fit pipefitting 10, the perimeter ring 40 rests on the step/seat

26 and the castellations 42 are oriented such that the castellations 42 slope from their root 43 towards the inside of the tubular body 12 i.e. towards the rib 28.

The direction of slope, the arrangement of the castellations 42 and the material of the castellated ring 14 is such that when a section of pipe 18 is inserted into the pipefitting 10 the castellations 42 will each deform elastically and the tip 41 of the castellations 42 will engage/grab the external wall of the end section of pipe 18 to provide a secure assembly of the pipe 18 and pipefitting 10. It will be appreciated the function of the castellations 42 is like barbs/spikes.

In the illustrated example, the ring seal member 15 is made of deformable synthetic rubber such that an internal member/deformable ring seal 48 of the ring seal member 15 facilitates sealing engagement between the pipefitting 10 and the external wall of an inserted section of pipe 18.

In the illustrated example the ring seal member 15 is a moulded unitary piece, where the ring seal member 15 includes a double wall structure. A first wall i.e. the external wall 46 is straight and perpendicular to the ends of the ring seal member 15. The external dimensions of the ring seal member 15 are such that it corresponds substantially with the internal circumference of the receiving ends 20, 22 of the tubular body 12 and with the dimension between the step/seat 26 and the ends 20, 22 of the tubular body 12 such that an outer face 47 of the ring seal member 15 engages with a grooved internal face 50 of the end cap 16. The ring seal member 15 acts as a retainer for the castellated ring 14, where the perimeter ring 40 of the castellated ring 14 is sandwiched between a retaining face of the ring seal member 15 and the step 26 when the pipefitting 10 is fully assembled as illustrated in Fig. 2, 3 and 4.

The second wall of the ring seal member 15 i.e. the internal wall defines the deformable ring seal 48. The deformable ring seal 48 is defined by a tapered/sloping surface, which extends longitudinally from one end (proximate the outer face) of the ring seal member 15 to a free end 49. The free end 49 of the deformable ring seal 48 is displaced from the internal surface of the first wall 46 and from the second end/inner face 51 of the ring seal member 15.

In the illustrated example, the deformable ring seal 48 and the ring seal member 15 are manufactured as a unitary piece. However, it will be appreciated that the ring seal member 15 and deformable ring seal 48 could be manufactured as separate components, where the ring seal member 15 would be provided by a housing into which the deformable ring seal 48 would be inserted/housed such that both components would be received in the tubular body 12 in a similar manner to the ring seal member 15 as described above in respect of a unitary piece.

The deformable ring seal 48 is configured to deform and engage with the external wall of a pipe-section 18 as it is inserted into the push-fit pipefitting 10 via the ends 20, 22.

When assembled with a section of pipe 18 the deformable ring seal 48 facilitates sealing engagement of the pipefitting 10 with the external surface of the section of pipe 18 received in the pipefitting 10.

As illustrated in Fig. 2 to Fig. 4, the assembled push-fit pipefitting 10, including a combination of the castellated ring 14 and a deformable ring seal 48, ensures a secure and watertight/leak proof assembly when combined with a section of pipe 18 inserted via each end 20, 22 of the pipefitting 10.

Installation of a section of pipe /pipe-end 18 into the pipefitting 10 is simplified compared with welded/cemented joints or compression fittings because each pipeend can be installed/assembled with the pipefitting 10 by a single action and without the need for cements/solvents or screw fittings. It will be appreciated the single action involves the installer inserting a prepared pipe-end 18 into an end 20, 22 of the pipefitting 10 with an applied slight force to first overcome the resilience of the internal deformable ring seal 48 and second to overcome the resistance to deform of the castellations 42 and thirdly coming to rest when the end face of the pipe 18 abuts the stop/rib 28 as an indication that the pipe 18 is fully installed. It will be appreciated, both the deformable ring seal 48 and the castellations 42 deform elastically to confirm with the surface profile of the pipe 18 to ensure a secure and leakproof pipe assembly.

To simplify assembly, and to ensure the desired secure and leakproof assembly is achieved, it will be appreciated that some preparation is recommended, for example ensuring the end face of the pipe 18 is perpendicular to the pipe wall, include a slight chamfer on the outer edge of the pipe-end and cleaning the pipe-end of debris or burrs. This preparation, which is typical for most pipe installations, ensures the deformable ring seal 48 is not damaged when the end of a pipe 18 is inserted into the pipefitting 10. In addition to preparing the pipe 18, easier insertion of the pipesection 18 can be assisted by lubricating/priming the surface of deformable ring seal 48 with a suitable lubricant/substance, for example silicone grease. An added advantage of installing the push-fit pipefitting 10 is, once installed the installation can be used immediately i.e. without any waiting time for cements to set.

The pipefitting 10 is labour-saving and simpler to install than conventional cemented joints or compression fitting joints. It is anticipated the burst pressure for a push-fit pipefitting as described and illustrated is approximately 8 bar due to the retaining action of the castellated ring 14. This pressure is greater than the burst pressure of a bonded ABS to ABS or PVC to PVC joint and a joint comprising a compression fitting, which are typically less than 8 bar. Whilst specific embodiments of the present invention have been described above, it will be appreciated that departures from the described embodiments may still fall within the scope of the present invention.