TECHNICAL FIELD

The present invention relates to the provision of junctions in pipes. Embodiments of the present invention find application, though not exclusively, in fields such as plumbing and the like.

BACKGROUND ART

Any discussion of documents, acts, materials, devices, articles or the like which has been included in this specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia or elsewhere before the priority date of this application.

When it is necessary to retro-fit a junction into an existing pipe various known prior art arrangements may be utilised. It has been appreciated by the inventors that the prior art arrangements may suffer from the following draw backs.

The prior art arrangements often do not effectively fix the depth by which the new pipe may extend into the existing pipe. Hence, there is a risk that over time the new pipe may protrude an unacceptably long distance into the existing pipe, which is likely to cause undesirable turbulence in the fluid flow in one or both of the pipes in the region of the junction, along with increasing the risk of blockages forming within the pipe.

To the best of the applicant's knowledge, the prior art arrangements are typically configured for mounting of the new pipe at right angles to the existing pipe. Forcing fluid to flow through such right angle junctions is also likely to cause undesirable turbulence.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome, or substantially ameliorate, one or more of the disadvantages of the prior art, or to provide a useful alternative. In one aspect of the present invention there is provided a pipe junction kit for creating a junction for the connection of a new pipe to an existing pipe, the kit including: a cylindrical grommet defining a proximal end and a distal end, wherein a flange is disposed at the proximal end at an oblique angle relative to a longitudinal axis of the grommet and wherein the distal end of the grommet is configured for connection to the new pipe; and a tensioning mechanism operable in use to exert a tension upon the grommet so as to abut the flange against an internal surface of the existing pipe.

Preferably the tensioning mechanism is a first lock nut threadedly engagable with the grommet so as to bear upon a distal end of a sleeve.

Preferably the distal end of the sleeve terminates at right angles relative to the longitudinal axis and a proximal end of the sleeve terminates at said oblique angle relative to the longitudinal axis.

Preferably the oblique angle is between 15° and 75°; more preferably it is between 30° and 60° and in a preferred embodiment it is 45°.

In one embodiment the distal end of the grommet is threadedly engagable with a second lock nut so as to clamp the new pipe onto the distal end of the grommet.

Preferably the flange is shaped so as, in use, to form a radially inwardly positioned gap between the flange and the internal surface of the existing pipe.

In one embodiment the flange resiliently deforms in response to said tension so as to reduce or eliminate the gap.

For cutting of the existing pipe a template may be used to define a cutting line. In this case the template is positioned upon the existing pipe so as to provide guidance for the cutting of the hole into the pipe.

In one embodiment the grommet is manufactured from a thermoplastic vulcanizate.

In another aspect of the present invention there is provided a method of creating a junction for the connection of a new pipe to an existing pipe, the method including the steps of: providing a pipe junction kit as described above; cutting an elongate hole into the existing pipe; threading a proximal end of the grommet into the elongate hole; and using the tensioning mechanism to exert a tension on the grommet so as to abut the flange against an internal surface of the existing pipe adjacent a periphery of the elongate hole.

Preferably the step of using the tensioning mechanism includes: threading the distal end of the grommet through a sleeve and seating a proximal end of the sleeve against an external surface of the existing pipe; and screwing a first lock nut onto the grommet such that the first lock nut bears upon a distal end of the sleeve so as to exert the tension.

In one embodiment of the method the step of cutting an elongate hole into the existing pipe includes: providing a template defining a cutting line; and cutting the pipe along the cutting line. In another embodiment of the method the step of cutting an elongate hole into the existing pipe includes: using a jig to mount a hole saw at the oblique angle relative to the pipe; and using the hole saw to cut the hole.

Preferably the method further includes the steps of engaging a new pipe with the distal end of the grommet screw; and screwing a second lock nut onto the distal end of the grommet so as to clamp the new pipe onto the grommet.

The features and advantages of the present invention will become further apparent from the following detailed description of preferred embodiments, provided by way of example only, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 is a cut away plan view of a pipe junction formed by an embodiment of the invention;

Figure 2 is a plan view showing some internal detail of a grommet used in the preferred embodiment;

Figure 3 is a cut away view of a pipe that is to be connected using the preferred embodiment;

Figure 4 is a cut away view of a pair of lock nuts used in the preferred embodiment; and

Figure 5 is a cut away view of a sleeve used in the preferred embodiment. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The preferred embodiment of the pipe junction kit can be used for creating a junction 2, as shown for example in figure 1, for the connection of a new pipe 3 to an existing pipe 4. The pipes 3 and 4 will typically be made from concrete, poly, plastic (PVC) or steel and will typically have an internal diameter of at least 225 mm. One particularly preferred application for the kit is for creating a pipe junction on corrugated plastic piping having a smooth inner bore and a corrugated outer surface.

As best shown in figure 2, the kit includes a cylindrical grommet 5 defining a proximal end 6 and a distal end 7. A flange 8 is disposed at the proximal end 6 at an oblique angle relative to the longitudinal axis of the cylindrical portion of the grommet 5. In the preferred embodiment the oblique angle is 45°. When measuring this oblique angle, it is necessary to ignore the curvature of the flange 8 that is needed to match the curvature of the interior side of the hole that is cut into the existing pipe 4. In other words, the oblique angle that the flange 8 makes relative to the longitudinal axis of the cylindrical portion of the grommet 5 is equal to the oblique angle between the existing pipe 4 and the new pipe 3 once the junction 2 has been fully installed. Other embodiments make use of alternative oblique angles which typically range between 15° and 75° and more preferably between 30° and 60°.

The distal end 7 of the grommet 5 is configured for connection to the new pipe 3. More specifically, the distal end 7 of the grommet 5 has a tapered portion 10 and an adjacent threaded portion 11. Lock nut 12, as shown in figure 4, can be screwed onto the threaded portion 11. The lock nut 12 has an internal tapered end 13, in which the tapering corresponds to the tapering of the tapered portion 10. When the lock nut 12 is screwed onto threaded portion, the two tapers eventually clamp against each other. This exerts a radially inward clamping force, which acts to clamp the new pipe 3 in place, thereby connecting the new pipe 3 to the grommet 5.

It will be appreciated by those skilled in the art that other connection means may be utilised to connect the new pipe 3 to the distal end 7 of the grommet 5. For example, other embodiments make use of a stainless steel hose clamp that either works in conjunction with, or replaces, the tapered portion 10, the threaded portion 11 and the lock nut 12. For this embodiment, the hose clamp encircles the grommet 5 and the portion of the new pipe 3 that is housed within the housing 25 of the grommet 5. This hose clamp is tightened by screwing a screw thread until the hose clamp exerts sufficient clamping force to retain the new pipe 3 within the housing 25.

The grommet 5 is manufactured from a thermoplastic vulcanizate. More specifically, it is injection moulded from a thermoplastic vulcanizate material sold commercially under the trade mark "Santoprene".

A tensioning mechanism 14 is operable in use to exert a tension upon the grommet 5 so as to abut the flange 8 against an internal surface 15 of the existing pipe 4. More specifically, another threaded portion 16 is disposed upon the grommet 5 on the proximal side of threaded portion 11. Another lock nut 17, as illustrated in figure 4, is threadable onto threaded portion 16. In use, this lock nut 17 bears upon a distal end 18 of sleeve 19. The sleeve 19 is best shown in figure 5 and it, along with the lock nuts 12 and 17 shown in figure 4, are made from PE100 Polyethylene, or a similar material. The distal end 18 of the sleeve 19 terminates at right angles relative to the longitudinal axis of the sleeve. However, as best illustrated in figure 5, the proximal end 22 of the sleeve 19 terminates at a 45° angle (ignoring the curvature of proximal edge 22, which is needed to match the curvature of the exterior side of the hole that is cut into the existing pipe 4).

As shown in figure 1, the sleeve 19 extends from lock nut 17 to abut against the external surface 20 of the existing pipe 4. Hence, once lock nut 17 is holding the sleeve 19 fast against the external surface 20 of the existing pipe 4, any further screwing of the lock nut 17 towards the existing pipe 4 tends to exert a tension down the length of the grommet 5. This forces the flange 8 hard up against the internal surface 15 of the existing pipe 4, which advantageously helps the flange 8 to form a water tight seal. The sandwiching of the existing pipe 4 between the flange 8 and the sleeve 19 advantageously resists against the junction 1 being pushed into, or pulled out of, the existing pipe 4.

As can be best seen in figure 1, the outer rim 21 of the flange 8 contacts against the internal surface 15 of the existing pipe 4 and the remainder of the flange 8 angles back from the internal surface 15. This shape forms a radially inwardly positioned gap 23 between the flange 8 and the internal surface 15 of the existing pipe 4, which provides some room for the flange 8 to resiliently deform in response to the tension exerted by the tensioning mechanism 14. If this tension is sufficiently strong, the flange 8 is deformed so as to reduce or eliminate the gap 23. It will be appreciated that if the gap 23 is eliminated, then the full length of the flange 8 is in contact with the internal surface 15 of the existing pipe 4.

The preferred embodiment of the pipe junction kit may be used in a method that commences with the cutting of an elongate hole into the existing pipe 4. The hole is a generally elliptical shape and it is a projection at the oblique angle of the cylindrical body of the grommet 5 onto the existing pipe. It will be appreciated that the shape of the hole is dependent upon the oblique angle selected for the junction 1. A larger oblique angle would generally require a less elliptical hole shape and vice versa. It will be appreciated that for the purposes of this document, the term "generally elliptical" is not to be construed in a formal mathematical sense. Rather, it is to be construed broadly enough to include any elongated hole shape.

One method for cutting the elongate hole into the existing pipe 4 is to include a template defining a cutting line in the kit. The template is positioned upon the existing pipe 4 and it is used to guide a reciprocating saw blade whilst cutting the hole into the pipe 4.

Another method for cutting the elongate hole into the existing pipe 4 includes the use of a jig to mount a circular hole saw at the selected oblique angle relative to the pipe 4. The hole saw then cuts the hole whilst it is being held in the desired position by the jig. Regardless of the particular method used to cut the hole, this step advantageously allows the user to precisely define the position at which the junction is to be installed.

Once the elongate hole has been formed in the pipe 4, the proximal end 6 of the grommet 5 is threaded into the elongate hole. This is possible despite the extra width of the flange 8 because of the elliptical shape of the hole in the pipe 4. The grommet 5 is held initially at or close to right angles to the pipe 4 and this allows the flange 8 to be inserted through the hole in the pipe 4. The grommet 5 is then rotated and pulled so as to position the outer rim 21 of the flange 8 against the internal surface 15 of the pipe 4.

Next the distal end 7 of the grommet 5 is threaded into the proximal end 22 of sleeve 19. The sleeve 19 is pushed towards the existing pipe until the curved proximal end 22 of the sleeve 19 is seated against the external surface 20 of the existing pipe 4. Next the tensioning mechanism is used to exert a tension on the grommet 5. More specifically, lock nut 17 is threaded onto threaded portion 16 until the lock nut 17 bears upon the distal end 18 of the sleeve 19. Further screwing of lock nut 17 exerts tension on the grommet 5, which causes the flange 8 to be abutted against the internal surface 15 of the existing pipe 4 around the periphery of the elongate hole.

To attach the new pipe 3 to the distal end 7 of the grommet 5, the new pipe is firstly loosely inserted into the pipe housing 25 defined within the grommet 5 until the proximal end of the new pipe 3 hits the stop 26 defined at the proximal end of the housing 25. Next, lock nut 12 is screwed onto threaded portion 11, which clamps the new pipe 3 onto the distal end of the grommet 5 in the manner described in detail above.

For some embodiments, it may be preferable to firstly loosely apply the lock nut 17, then to attach the new pipe 3 to the distal end of the grommet 5 and finally to tighten the locking nut 17 so as to force the flange 8 hard up against the internal surface 15.

The oblique angle pipe junctions provided by the present invention compare favourably with the prior art in which the pipe junctions are typically configured at 90°. An oblique angle such as 45° advantageously promotes smoother fluid flow in the region of the junction as compared with the fluid flow in the 90° prior art junctions. Additionally, the present invention ensures that the grommet 5 can only protrude a fixed length into the existing pipe 4, which assists with fluid flow and the avoidance of blockages. The use of the kit also typically provides substantial costs savings as compared to the option of custom fabricating a new junction. Advantageously, the preferred embodiment also helps to minimise wasted pipe offcuts. Additionally, the use of high quality materials, such as PE100 polyethylene and thermoplastic vulcanizate in the form of Santoprene, yields a high quality junction having favourable strength properties and a long anticipated service life.

While a number of preferred embodiments have been described, it will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.