WO2004046603A1

WO2004046603A1 - Improved pipe connector

Info

Publication number: WO2004046603A1
Application number: PCT/AU2003/001545
Authority: WO
Inventors: Guy Malcolm Phillipps
Original assignee: JTL AUSTRALIA Pty Ltd
Current assignee: JTL AUSTRALIA Pty Ltd
Priority date: 2002-11-19
Filing date: 2003-11-19
Publication date: 2004-06-03
Anticipated expiration: 2005-05-19
Also published as: AU2002952729A0

Abstract

A telescopic pipe fitting (10) for joining two spaced apart axially aligned pipe ends (6 & 8) is disclosed. The pipe fitting comprises: a hollow body (20) defining an inner bore and having an end (28); an extension tube (30) telescopically mounted within the inner bore; an intermediate annular seal disposed between the tube (30) and the inner bore of the body (20) effecting a seal there-between; and a retaining means (40) for retaining the extension tube (30) within the inner bore. First and second joining means (50 & 70) are provided for mechanically and sealably joining the fitting (10) the pipe ends (6 & 8) respectively. The tube (30) is telescopically movable with respect to the body (20) so as to vary the spacing between the end of the body (28) and the end of the extension tube (38) so as to allow installation between the pipe ends (6 & 8) without the need to move the pipe ends.

Description

IMPROVED PIPE CONNECTOR

FIELD OF THE INVENTION

The present invention relates to pipe repair and pipe take-off methods and pipe fittings therefor. The invention relates in particular to methods and pipe fittings suitable for sealably joining spaced-apart axially aligned pipe ends.

BACKGROUND

Low cost irrigation pipes or "rural pipes" are commonly made with nominal diameters of VΪ, ³Λ, 1, VΛ, VA and 2 inches in polyethylene. Such pipes are typically joined by mechanical compression fittings. Generally, these imperial sized fittings require a barbed insert or liner to act as a stiffener to prevent the pipe wall from collapsing under compression and to provide a tail or spigot having a specific sized outer diameter for insertion into the fitting. In some cases metric sized fittings also require a barbed insert.

Rural compression fittings or mechanical couplings, whether they be straight joiners, tees, elbows or threaded end connectors typically comprise a central body, an insert (liner), collapsible gripper ring, a nut and a seal ring. The seal ring can either be attached to the insert or housed within the body of the main fitting. Alternatively, some fittings have the insert attached to the main body and a threaded nut that winds back over the pipe collapsing the pipe wall onto the insert to form a watertight seal.

The most common fitting to pipe assembly process requires a pipe to be cut to the required length. A nut is then passed over the outside of the pipe followed by a gripper ring prior to pushing an insert into the bore of the pipe. The fitting body is then pushed into the insert and a seal is created between the insert and fitting body by deformation of a seal. The nut is tightened forcing the gripping member to bite into the pipe, thereby collapsing the wall of the pipe onto an insert with raised barbs on the outside surface of the insert forming a watertight seal between the inside wall of the pipe and the outside of the insert.

In most applications, the pipe is buried in a trench below the surface of the ground. The fittings are usually installed prior to the trench being filled in. In this situation, there is usually adequate room to flex the pipe so as to adjust the path of the pipe and to manipulate the pipe end making assembly relatively easy and quick. Thus, mechanical compression fittings have become commonly used for the construction and repair of rural irrigation pipes. Difficulties do arise, however, with repairs and modifications to existing rural piping systems, particularly where the piping is buried.

Should a take-off be required, should insertion of an isolating valve be required or should the pipe form a leak, it is necessary to dig down to the pipe to expose the leak or area where the modification is required. To make a joint it is necessary to dig the pipe back some distance to enable sufficient flex in the pipe to manipulate the pipe end to push the tail of the insert (the spigot) into the body of the fitting to form a seal. In many instances in repair situations the repair may require two fittings and a piece of pipe to fix the damaged pipe. The pipe can also contract when the pipe is cut making the gap too long for a single coupling or joiner to be used.

The process of digging to clear around a significant length of pipe either side of the area to be repaired, or the area in which a modification is required, is time consuming and costly. Care must be taken to ensure the pipe is not further damaged in the process.

A further problem with existing techniques is that generally the user must allow time for glued joints to cure before the pipe can be pressurised.

A still further problem with existing techniques is that a clean and dry environment is required to achieve reliable mechanical and/or sealed joints. For example, existing techniques make repair difficult in a submerged environment or an environment where flow and hence pressure from the pipe to be repaired or modified cannot be isolated.

It is an object of the present invention to overcome at least some of the above problems.

It is a further object of the invention to provide a pipe fitting that provides sealed communication across a gap between two spaced apart axial line pipes without the need to move either of the pipe ends axially.

It is a further object of the invention to provide a pipe fitting that provides sealed communication across a gap between two spaced apart axial line pipes without curing time being required before pressurisation.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a telescopic pipe fitting for joining two spaced apart axially aligned pipe ends, the pipe fitting comprising: a hollow body defining an inner bore and having a proximal and a distal end; an extension tube telescopically mounted within the inner bore, the extension tube having a distal and a proximal end; an intermediate annular seal disposed between the proximal end of the extension tube and the inner bore of the body effecting a seal there-between; a retaining means for retaining the extension tube within the inner bore; a first joining means for mechanically and sealably joining the distal end of the extension tube to a first of the pipe ends, the first joining means mounted to, or integral with the distal end of the extension tube; and a second joining means for mechanically and sealably joining the distal end of the body to a second of the pipe ends, the second joining means mounted to, or integral with the distal end of the body; wherein the extension tube is telescopically movable with respect to the body so as to vary the spacing between the distal end of the body and the distal end of the extension tube so as to allow installation between the first and second pipe ends without the need to move the pipe ends axially.

Preferably the retaining means comprises a first abutment surface depending from the body and a second abutment surface depending from the extension tube.

Preferably the retaining means comprises: a retaining nut threadably mounted to the proximal end of the body, the retaining nut having an internally tapered end; and a retaining wedging ring extending circumferentially around the extension tube, the retaining wedging ring having a tapered surface co-operable with the internally tapered end of the retaining nut, wherein the first abutment surface is defined by a surface of the retaining wedging ring.

Preferably the second abutment surface is defined by a projection extending around the periphery of the proximal end of the extension tube.

Preferably tightening of the retaining nut causes wedging of the retaining wedging ring between the internally tapered end of the nut and the extension tube so as to centre the extension tube with respect to the body.

Preferably the first joining means comprises: a first end nut threadably mounted to the distal end of the extension tube, the first end nut having an internally tapered end; and a first end wedging ring having a tapered external surface co-operable with the internally tapered end of the first end nut and a barbed internal surface for gripping the outside of the first pipe end, the first end wedging ring held captive between the first end nut and the extension tube, wherein, in use, tightening of the first end nut causes wedging of the first end wedging ring between the internally tapered end of the first end nut and the first pipe end so as to lock the extension tube with respect to the first pipe end.

Preferably the second joining means comprises: a second end nut threadably mounted to the distal end of the extension tube, the second end nut having an internally tapered end; and a second end wedging ring having a tapered external surface co-operable with the internally tapered end of the second end nut and a barbed internal surface for gripping the outside of the second pipe end, the second end wedging ring held captive between the second end nut and the extension tube, wherein, in use, tightening of the second end nut causes wedging of the second end wedging ring between the internally tapered end of the second end nut and the second pipe end so as to lock the body with respect to the second pipe end.

Preferably the fitting further comprises: a first end annular seal; and a first insert having a first barbed end for insertion into the first pipe end and a first spigot end for sealably cooperating with the first annular seal to provide a seal between the first spigot end and the extension tube.

Preferably the fitting further comprises: a second end annular seal; and a second insert having a second barbed end for insertion into the second pipe end and a second spigot end for sealably cooperating with the second annular seal to provide a seal between the second spigot end and the body.

According to a second aspect of the invention there is provided a method of providing sealed communication across a gap between two spaced apart axially aligned pipe ends without the need to move either of the pipe ends axially, the method comprising the steps of: inserting a first barbed end of a first insert into a first of the two pipe ends, the first insert having a first spigot end for sealably cooperating with a first annular seal; inserting a second barbed end of a second insert into a second of the two pipe ends, the second insert having a second spigot end for sealably cooperating with a second annular seal; inserting a telescopically adjustable pipe fitting between the spigot ends, the fitting having a through-bore between a first fitting end and a second fitting end; sliding the first fitting end over the first spigot end; telescopically extending the fitting until the second fitting end slides over the second spigot end; effecting a seal between the first spigot end, the first annular seal and the first fitting end; and effecting a seal between the second spigot end, the second annular seal and the second fitting end.

Preferably the steps of effecting a seal occur as the fitting ends slide over the spigot ends.

Preferably the method further comprises the steps of: locking the extension tube with respect to the first pipe end; and locking the body with respect to the second pipe end.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

A preferred embodiment of the invention is illustrated in the accompanying representations in which:

Figure 1 shows an exploded perspective view of a telescopic pipe fitting according to a first embodiment of the invention; Figure 2 shows a trench exposing pipe ends ready to be joined by the telescopic pipe fittings shown in Figure 1;

Figure 3 shows the telescopic pipe fitting in Figure 1 being used to join the pipe ends shown in Figure 2; Figure 4 is a cross-sectional view of the telescopic pipe fitting shown in Figure 1 in a retracted condition;

Figure 5 is a similar view to that of Figure 4 but shows the telescopic fitting in an extended position;

Figure 6 is a side view of the body of the telescopic pipe fitting shown in Figure 1;

Figure 7 is a cross-section view of the body shown in Figure 6;

Figure 8 is an end view of the body shown in Figure 6;

Figure 9 is a side view of the extension tube of the telescopic pipe fitting shown in Figure 1; Figure 10 is a cross-sectional view of the extension tube shown in Figure 9;

Figure 11 is an end view of the extension tube shown in Figure 9; and

Figure 12 is a perspective view of an alternative body to the body shown in Figures 9, 10 and 11.

Referring to Figures 1 and 4, a telescopic pipe fitting 10 according to a first embodiment of the invention is shown. The pipe fitting 10 comprises of a hollow body 20, an extension tube 30 and a retaining means 40 for retaining the extension tube 30 within the body 20. The hollow body 20 defines an inner bore 25 and has a proximal end 22 and distal end 28. The inner bore 25 receives the proximal end 36 of the extension tube 30. A pair of intermediate annular seals in the form of "O" rings 34 are provided to affect a seal between the extension tube 30 and the inner bore 25 of the body 20. While in this embodiment of the invention a pair of annular O-ring seals are used, other sealing arrangements may be used. The extension tube 30 is telescopically movable with respect to the body 20 so as to vary the spacing between the distal end 28 of the body 20 and the distal end 38 of the extension tube 30 so as to allow installation of the fitting 10 between first and second pipe ends 6 and 8, such as those shown in Figures 2 and 3, without the need to move the pipe ends 6 and 8 axially. In contrast, with prior art techniques significant excavation involving breaking up of asphalt and /or concrete is often required to allow the pipe ends to be manipulated so as to achieve the axial movement necessary to position them within fitting ends.

Figure 2 shows the pipe ends 6 and 8 exposed within a trench in the ground 5. Installation of the telescopic pipe fitting 10 between the two spaced apart axially aligned pipe ends 6 and 8 is clearly shown in Figure 3.

The pipe fitting 10 includes a retaining means 40 best illustrated by Figure 4. Retaining means 40 retains the extension tube 30 within the inner bore 25 of the body 20. With the embodiment of the invention illustrated, the retaining means 40 comprises a retaining nut 42 that is threadably mounted to the proximal end 22 of the body 20. The retaining nut 42 has an internal tapered end 44 best shown in Figure 5. A retaining wedging ring 45 extends circumferentially around the extension tube 30 as is shown in Figure 5. The retaining wedging ring 45 has a tapered surface that is co-operable with the internally tapered end 44 of the retaining nut 42. The retaining wedging ring 45 has a plurality of barbs 47 that provide a first pair of annular abutment surfaces which effectively depend from the body by virtue of the nut 42 being threaded onto the body 20. A second pair of annular abutment surfaces are provided by corresponding barbs 37 that extend from the extension tube. Barbs 37 are most clearly illustrated in Figure 9.

The inter-engaging barbs 37 and 47 provide a positive lock that ensure the shaft 35 will not telescope completely out of the inner bore 25 under hydraulic pressure or due to excessive retraction of either of pipe ends 6 or 8.

A second function of the retaining means 40 is to centrally locate the shaft to prevent bending loads from occurring and possibly deforming the seal between the shaft 35 and the internal bore 25 to allow it to leak. The retaining means 40 is arranged and constructed to hold the extension tube 30 in a position coaxial with the body 20. The co-operable action between the wedging ring 45 and the internally tapered end 44 of the lock in nut 42 ensure that when tightened, the retaining means 40 holds the shaft 35 into the centre of the inner bore 25. Furthermore, at the proximal end 36 of the extension tube 30 the annular intermediate "O" ring seals 34, together with the small clearance between the proximal end 36 and the inner bore 25, ensure that the proximal end 36 remains centred with respect to the inner bore 25. This reduces the possibility of leakage.

An end stop 26 clearly shown in Figure 7 is provided at the end of the inner bore 25, limiting the inwards travel of the extension tube 30 with respect to the hollow body 20. An abutment surface 33 is provided towards the distal end 38 of the extension tube 30. This abutment surface 33 assists in releasing the retaining wedging ring 45 to allow free movement of the retaining wedging ring 45 along the outside of the extension tube 30.

To facilitate connection of the telescopic pipe fitting 10 to pipe ends, first and second joining means 50 and 70 are provided at its ends. These joining means 50 and 70 are shown in Figure 3.

A first joining means 50 is shown at the distal end 38 of the extension tube 30. This joining means 50 mechanically and sealably joins the distal end 38 to a first pipe end 6 as shown in Figure 3. The first end wedging ring 55 (not shown) can be identical to the corresponding retaining wedging ring 45 used for the retaining means 40 (shown in Figure 1). This allows for interchangeability of parts which has advantages both for the user and in relation to cost to manufacture and inventories. The nut 52 and nut 42 are identical, but in other embodiments of the invention may be constructed differently.

The insert 65 performs two functions. Firstly, the wall thickness of a typical plastics imperial pipe is inadequate to allow effective clamping by the wedging ring 55 (not shown). The insert stiffens the pipe end 6. Secondly the insert 65 provides a tail or spigot end 67 with an outer diameter of a standard metric size. The tail 67 or spigot end 67 engages an annular seal 60 as shown in Fig. 5. Various annular seals 60 may be used. In this embodiment, the seal has a "D" shaped cross-section. Thus, the first joining means 50 can be used to connect an imperial pipe end 6 with an insert 65 in its end.

Alternatively fitting 10 can be used to join a plain ended plastics metric pipe (without an insert 65) using a different sized wedging ring 55 (not shown) and metric nut 52.

While a specific first joining means 50 is shown in Figure 1, alternatives could be used. For instance the distal end 38 of the extension tube 30 could comprise a threaded section and /or the distal end 28 of the body 20 could comprise a threaded section. A further alternative would be a barbed tail piece and a nut with an internally threaded conical section arranged to grip into an outer wall of a plastic pipe upon tightening.

Again referring to Figure 1, a second joining means 70 is provided at the distal end 28 of the hollow body 20. With this embodiment of the invention, the second joining means 70 is the same as the first joining means 50. However as for first joining means 50, alternative joining means can be used.

Referring to Figure 12, a body 20 for a second embodiment of the invention is shown.

With the second embodiment of the invention, the body 20 includes a take off 90. In other respects, the fitting 10 is identical to the fitting 10 shown in Figures 1 to 11. With this embodiment, the take off 90 is orientated at right angles with respect to the extension tube shaft 35, however various angles may be used to create "T" joints, "Y" joints or other arrangements.

With further embodiments of the invention, not shown, isolation valves or other piping elements may be incorporated or connected into the telescopic pipe fitting 10. A method, according to a second aspect of the invention, of providing sealed communication across a gap between two spaced apart axial lined pipe ends without the need to significantly move either of the pipe ends will now be described. In particular, with this method it is not necessary to move the pipe ends axially or longitudinally. Typically, rural pipe will be buried below ground and the first step in repairing a leak in the underground pipe or inserting a take-off or isolation valve using this method is to dig around the area of the leak or the area in which the modification is required to expose the pipe. Figure 2 shows such an excavation. In Figure 2 it can be seen that the pipe ends 6 and 8 have been cut cleanly. It is then possible to insert a first barbed end of a first insert 65 into a first of the two pipe ends 6. The first insert 65 has a first spigot end 67 for sealably co-operating with a first annular seal 60 as is best seen in Figure 5. A second barbed end of a second insert 85 can be inserted into a second of the two pipe ends 8 in a similar way (see Figure 4). A telescopically adjustable pipe fitting 10, such as the fitting shown in Figure 1 can then be inserted between the spigot ends 67 and 87. The first fitting end 28 of the telescopically ajustable pipe fitting can then be slid over the first spigot end 67. Next the fitting can be telescopically extended until the second fitting end 38 slides over the second spigot end 87.

With the installation method described above, a seal is affected as the fitting ends slide over the spigot ends. This provides an immediate seal, thereby providing sealed communication across the gap between the two spaced apart pipe ends, 6 and 8, without the need to move either of the pipe ends, 6 and 8 to any great extent.

Before back-filling the trench, the extension tube 30 can be locked with respect to the first pipe end 6, for instance by tightening nut 52 and the body 20 can be locked with respect to the second pipe end 8, for instance by tightening nut 72 before the trench is back-filled. The method may also include tightening of a centre nut, such as the nut 40 shown in Figure 3 to centralise the shaft 35 (shown in Figure 4) to restrict movement that may be caused by bending loads. With the pipe fitting 10 shown in Figures 1 to 11, tightening of the centre nut 42 also has the effect of providing an abutment surface to prevent blow-out of the shaft 35 from the body 20.

While the present invention caters for imperial rural pipe applications it will also find application in metric pipe systems particularly where repair work is required in confined spaces or where modifications to underground lines are required. For example connection to a pumping system may be facilitated by the two embodiments of the telescope fitting 10 described above with reference to Figs 1 to 11 and 12 respectively.

While the present invention has been described in terms of preferred embodiments in order to facilitate better understanding of the invention, it should be appreciated that various modifications can be made without departing from the principles of the invention. Therefore, the invention should be understood to include all such modifications within its scope.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A telescopic pipe fitting for joining two spaced apart axially aligned pipe ends, the pipe fitting comprising: a hollow body defining an inner bore and having a proximal and a distal end; an extension tube telescopically mounted within the inner bore, the extension tube having a distal and a proximal end; an intermediate annular seal disposed between the proximal end of the extension tube and the inner bore of the body effecting a seal there-between; a retaining means for retaining the extension tube within the inner bore; a first joining means for mechanically and sealably joining the distal end of the extension tube to a first of the pipe ends, the first joining means mounted to, or integral with the distal end of the extension tube; and a second joining means for mechanically and sealably joining the distal end of the body to a second of the pipe ends, the second joining means mounted to, or integral with the distal end of the body; wherein the extension tube is telescopically movable with respect to the body so as to vary the spacing between the distal end of the body and the distal end of the extension tube so as to allow installation between the first and second pipe ends without the need to move the pipe ends axially.

2. A pipe fitting as claimed in claim 2 wherein the retaining means comprises a first abutment surface depending from the body and a second abutment surface depending from the extension tube.

3. A pipe fitting as claimed in claim 3 wherein the retaining means comprises: a retaining nut threadably mounted to the proximal end of the body, the retaining nut having an internally tapered end; and a retaining wedging ring extending circumf erentially around the extension tube, the retaining wedging ring having a tapered surface co-operable with the internally tapered end of the retaining nut, wherein the first abutment surface is defined by a surface of the retaining wedging ring.

4. A pipe fitting as claimed in claim 3 wherein the second abutment surface is defined by a projection extending around the periphery of the proximal end of the extension tube.

5. A pipe fitting as claimed in claim 4 whereby tightening of the retaining nut causes wedging of the retaining wedging ring between the internally tapered end of the nut and the extension tube so as to centre the extension tube with respect to the body.

6. A pipe fitting as claimed in claim 5 wherein the first joining means comprises: a first end nut threadably mounted to the distal end of the extension tube, the first end nut having an internally tapered end; and a first end wedging ring having a tapered external surface co-operable with the internally tapered end of the first end nut and a barbed internal surface for gripping the outside of the first pipe end, the first end wedging ring held captive between the first end nut and the extension tube, wherein, in use, tightening of the first end nut causes wedging of the first end wedging ring between the internally tapered end of the first end nut and the first pipe end so as to lock the extension tube with respect to the first pipe end.

7. A pipe fitting as claimed in claim 6 wherein the second joining means comprises: a second end nut threadably mounted to the distal end of the extension tube, the second end nut having an internally tapered end; and a second end wedging ring having a tapered external surface co-operable with the internally tapered end of the second end nut and a barbed internal surface for gripping the outside of the second pipe end, the second end wedging ring held captive between the second end nut and the extension tube, wherein, in use, tightening of the second end nut causes wedging of the second end wedging ring between the internally tapered end of the second end nut and the second pipe end so as to lock the body with respect to the second pipe end.

8. A pipe fitting as claimed in claim 7 further comprising: a first end annular seal; and a first insert having a first barbed end for insertion into the first pipe end and a first spigot end for sealably cooperating with the first annular seal to provide a seal between the first spigot end and the extension tube.

9. A pipe fitting as claimed in claim 8 further comprising: a second end annular seal; and a second insert having a second barbed end for insertion into the second pipe end and a second spigot end for sealably cooperating with the second annular seal to provide a seal between the second spigot end and the body.

10. A method of providing sealed communication across a gap between two spaced apart axially aligned pipe ends without the need to move either of the pipe ends axially, the method comprising the steps of: inserting a first barbed end of a first insert into a first of the two pipe ends, the first insert having a first spigot end for sealably cooperating with a first annular seal; inserting a second barbed end of a second insert into a second of the two pipe ends, the second insert having a second spigot end for sealably cooperating with a second annular seal; inserting a telescopically adjustable pipe fitting between the spigot ends, the fitting having a through-bore between a first fitting end and a second fitting end; sliding the first fitting end over the first spigot end; telescopically extending the fitting until the second fitting end slides over the second spigot end; effecting a seal between the first spigot end, the first annular seal and the first fitting end; and effecting a seal between the second spigot end, the second annular seal and the second fitting end.

11. A method as claimed in claim 10 wherein the steps of effecting a seal occur as the fitting ends slide over the spigot ends.

12. A method as claimed in claim 11 further comprising the steps of: locking the extension tube with respect to the first pipe end; and locking the body with respect to the second pipe end.