WO2009004303A1

WO2009004303A1 - Sealing a leak in a pipe joint

Info

Publication number: WO2009004303A1
Application number: PCT/GB2008/002185
Authority: WO
Inventors: Michael David Wild
Original assignee: M W Polymer Products Ltd
Priority date: 2007-06-29
Filing date: 2008-06-26
Publication date: 2009-01-08
Also published as: GB0712555D0

Abstract

A method for sealing a leak in a pipe joint (16), the method comprising inserting a hose (60) through a hole to extend around an annular void (27) between a gasket (22) and the interior of a pipe (12,14), and injecting sealant into the hose (60) to inflate the same and also to pass out through holes in the hose (60). Thereby, a sealant plug (70) forms a circumferentially extending impervious barrier and seals the leak in the pipe joint (16).

Description

Sealing a Leak in a Pipe Joint

The present invention relates to methods for sealing leaks in pipe joints.

The most^, common type of joint in pipes carrying natural gas is known as a bell and spigot joint, also known as a spigot and socket joint. This joint consists of a bell-shaped end region on one section of the pipe which receives into it an end region of the adjacent section of the pipe. The annular void between the end regions of the two sections is packed with a hemp, jute or yarn material to form a gasket. Over this is provided packing material in the form of a lead or cement O-ring which extends between the gasket and the region external of the pipe. The O-ring is applied to provide mechanical strength to the seal in the joint.

The material used to form the gasket typically contains about 75% to

80% water, which gradually evaporates. This causes the gasket to shrink and decay over time. In addition, movement of the ground causes the O-ring to distort. As a result of these factors, there is often leakage of gas from such pipe joints.

One method for repairing such pipe joints is described in the applicant's earlier US patent no. US 6634074. The present invention aims to provide an alternative and/or improved method for sealing a leak in a pipe joint.

According to a first aspect of the present invention, there is provided a method for sealing a leak in a pipe joint between first and second pipe sections having an annular gasket at the joint, the gasket being located in an enlarged head at an end of the pipe section, which head receives an end of the second pipe section with the gasket provided around the second pipe section adjacent said end thereof, the method comprising inserting a sealant guiding member into an annular void adjacent to the gasket on an opposite side thereof to the remainder of the second pipe section and within the enlarged head, and thereafter injecting sealant into the sealant guiding member to provide a circumferential seal around the annular void and repair the leak.

The sealant guiding member may be elongate and may define a hollow passage. Injected sealant may be guided by the hollow passage circumferentially around the annular void and may flow along the hollow passage during the step of injecting sealant into the sealant guiding member.

The sealant guiding member may comprise a flexible tube, for example a hose. A plurality of holes may be provided through the walls of the tube, and a greater concentration of holes may be provided towards a distal end of the tube.

The sealant guiding member may be formed of a permeable material which may permit sealant to flow therethrough. The permeable material may be a braided material and the sealant guiding member may comprise a braided hose.

Sealant may flow through the permeable material during the step of injecting sealant into the sealant guiding member. The sealant may flow from the hollow passage, outwardly through the guiding member during the step of injecting sealant into the sealant guiding member.

The method may comprise inserting an insertion member into the sealant guiding member prior to inserting the sealant guiding member into the annular void. The method may thus comprise inserting the insertion member and the sealant guiding member into said annular void adjacent to the gasket, between the gasket and the internal region of the pipe. The method may comprise inserting the insertion member into the hollow passage so that it extends fully through the insertion member, along the full length of the passage.

The insertion member may be elongate and may comprise a stiff elongate member. The insertion member may be semi-rigid and may be malleable. The insertion member advantageously has sufficient rigidity to allow it to be inserted circumferentially into the annular void and may be sufficiently malleable to be deformed by the pipe wall so that it follows the circumferential path of the annular void.

The insertion member may comprise a wire, for example a single-piece wire which may be semi-rigid.

The method may comprise removing the insertion member from the sealant guiding member prior to injecting the sealant into the sealant guiding member.

The method may comprise creating a through bore in the first pipe section, between the exterior of the pipe joint and the annular void, advantageously prior to inserting the sealant guiding member into the annular void. This may advantageously provide access to the annular void from the exterior of the pipe joint. The method may comprise inserting the sealant guiding member through the created through bore into the annular void.

The step of creating the through bore in the first pipe section may comprise drilling a hole in the first pipe section. The step of drilling the hole may comprise initially drilling a blind hole and thereafter extending the blind hole to form the through bore, for example by further drilling.

The method may comprise inserting an injection facilitation member into the through bore, and may comprise inserting the injection facilitation member into the through bore prior to inserting the sealant guiding member into the annular void. The method may comprise inserting the injection facilitation member into the blind hole before the blind hole is extended to form the through bore. The method may comprise forming a thread in the blind hole, for example by tapping the blind hole, so that the injection facilitation member may be threadably inserted into the aforesaid blind hole.

The through bore may be inclined away from a radial direction, and may be inclined so as to extend into the annular void but not into the second pipe section.

The step of drilling the hole in the first pipe section to form the through bore may comprise locating a drilling jig on the first pipe section, and advantageously on an upper region of the first pipe section.

An elongate clearer member may be introduced into the through hole to remove any debris, and to confirm if the annular void is clear to receive the insertion member around the whole circumference of the void. If the annular void is not clear, a further through hole may be formed but extending in a different direction to the original through hole.

The drilling jig may define a fixing aperture, and the method may comprise forming a fixing hole in the first pipe section through the fixing aperture. The drilling jig may be secured to the first pipe section by suitable fastening means extending through the fixing aperture in the drilling jig. The fastening means may extend into the fixing hole in the first pipe section. The fastening means may comprise a fixing pin or a fixing bolt. The method may comprise hand tightening the fixing bolt into the hole in the first pipe section.

The drilling jig may comprise a first drill guide for drilling the through hole . The first drill guide may be spaced circumferentially from the fixing aperture and/or may be spaced longitudinally from the fixing aperture. The first drill guide may be connected to a parallel follower, which follower can rest tangentially on the second pipe section spaced from the first pipe section, to provide a required alignment of the first drill guide.

The first drill guide may be pivotally mounted on the drilling jig, and lockable at a required orientation thereon. The first drill guide may be movable in a longitudinal direction, and lockable in a required longitudinal position.

The method may also include the step of drilling through the gasket in a generally longitudinal direction to provide a gasket hole. A second drill guide may be provided for drilling the hole through the gasket at a required inclination. The second drill guide may be mounted on the drilling jig, and may be movably mounted on the drilling jig, and lockable in a required position.

The drilling jig may include an elongate guide extendable from the first pipe section parallel to and spaced from the second pipe section, with the second drill guide slidably mounted on the elongate guide. The second drill guide may include a guide passage inclined gently away from the elongate guide, such that movement of the second drill guide towards or away from the gasket, will determine the radial position of the hole being drilled through the gasket.

A feeler member may be extendable through the gasket hole to locate the position of the end of the second pipe section, and/or other features of the second pipe section and also the gasket. The feeler member may be elongate with an inclined end, and may be rotatable relative to the gasket hole to enable the features to be felt. The feeler member may be mounted in a sleeve extendable through the gasket hole. The drilling jig may include a mounting plate, slidably movable relative to the fixing aperture. A plurality of holes or other formations may be provided on the mounting plate to permit the first drill guide to be mounted thereqn at a required position.

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

Fig. 1 is a diagrammatic part cross-sectional view of a pipe joint;

Fig. 2 is a diagrammatic perspective view of part of the pipe joint of Fig. 1 in the process of being repaired by a first method according to the invention;

Figs. 3 to 6 are diagrammatic perspective views of the pipe joint of Fig. 2 during further stages of the first method;

Fig. 6a is a diagrammatic view of part of a sealant guiding member and of part of an insertion member used in the first method;

Fig. 7 is a diagrammatic part cross-sectional view of the pipe joint of

Figs. 2 to 6 during a further stage of the first method;

Figs. 8 and 9 are diagrammatic perspective views of the pipe joint of Figs. 2 to 7 during further stages of the first method;

Fig. 10 is a diagrammatic perspective cut-away view of part of a pipe joint repaired by the first method;

Fig. 11 is a diagrammatic part cross-sectional view of the repaired pipe joint of Fig. 10; Figs. 12 to 18 are sequential diagrammatic sectional side views of a pipe joint being repaired by a second method according to the invention;

Fig. 19 is a diagrammatic side view of apparatus usable in the second method according to the invention;

Fig. 20 is a diagrammatic rear view of the apparatus of Fig. 19;

Fig. 21 is a diagrammatic front perspective view of the apparatus of Fig. 19;

Fig. 22 is a part dissembled diagrammatic rear perspective view of part of the apparatus of Fig. 19;

Fig. 23 is a rear perspective view of the apparatus of Fig. 19 in use;

Fig. 24 is of a similar view to Fig. 23 but in a different stage of the method;

Fig. 25 is a diagrammatic cross sectional view through a further part of the apparatus usable in the invention;

Fig. 26 is a diagrammatic view through part of the apparatus shown in Fig. 25; and

Fig. 27 is a similar view to Fig. 26 but of a further part of the apparatus.

Referring initially to Fig. 1, a pipe 10 comprises first and second pipe sections 12, 14 which are connected together at a joint 16. The pipe centreline is denoted as A-A and the first and second pipe sections 12, 14 extend circumferentially about the centreline A-A. The joint 16 is provided by a bell-shaped end region 18 of the first pipe section 12 which is of larger inner diameter than the outer diameter of an end region 20 of the second pipe section 14, so that the end region 20 is received within the end region 18. Joints of this type are commonly known as a 'bell and spigot' joint, and also as a 'spigot and socket' joint.

A gasket 22 is provided in the annular region 23 defined between the bell-shaped end region 18 of the first pipe section 12 and the end region 20 of the second pipe section 14. The gasket 22 is of an annular configuration, and can be formed of hemp, yarn, jute, or of any other suitable material. At the outer end 24 of the bell-shaped end region 18 there is provided a lead or cement O-ring 26. This construction of pipe joint 16 is common in many pipes, and always includes an annular void 27 between the gasket 22 and the interior 25 of the pipe 10.

As indicated above, the material forming the gasket 22 is prone to decay over time. Moreover, ground movement can distort the O-ring 26. Consequently, the joint 16 can fail, allowing gas or other fluid flowing through the pipe to escape, thereby forming a leak in the pipe joint 16, as illustrated diagrammatically by the arrows L in Fig. 7.

Referring now to Figs. 2 to 11 , there are shown the stages in the repair of the leaking pipe 10, by sealing the leak in the pipe joint 16 using a first method according to the invention.

Referring initially to Figs. 2 to 4, a drilling jig 28 is arranged at an upper position, for example the twelve o'clock position, on the end region 18 of the first pipe section 12. The drilling jig 28 comprises a securing portion 30 which includes a curved region 32, to follow the curvature of a circumferential lip 18a at the outer end 24 of the end region 18, and side walls 34. The curved region 32 and the side walls 34 together define a recessed portion which in which the circumferential lip 18a can be snugly received to thereby enable accurate axial positional location of the drilling jig 28 on the first pipe section 12.

The securing portion 30 includes a fixing aperture 36 and is fixed to the end region 18 to prevent circumferential movement around the lip 18a by firstly drilling a blind hole into the lip 18a using a drill bit 38 having a depth limiting member 38a and by thereafter passing a locating pin 40 through the fixing aperture 36 and into the blind hole. If the locating pin 40 is threaded, the blind hole can be tapped to form a thread, thereby enabling the threaded locating pin 40 to be threadably located in the threaded fixing aperture, for example by hand tightening the threaded locating pin 40.

The drilling jig 28 further includes a guide portion 42 which extends longitudinally from the securing portion 30, axially along the first pipe section 12 in a direction away from the end region 18 thereof. The guide portion 42 includes drill guide means 44 for guiding a drill bit 46, and due to its location on the guide portion 42, the drill guide means 44 is spaced axially from the securing portion 30.

The axial spacing between the securing portion 30 and the drill guide means 44 is an important aspect of the present invention. In particular, in pipe joints 16 of the type described with reference to Fig. 1 , the position of the annular void 27 can be readily determined based on standard dimensions for pipes that employ such joints. Thus, by selecting a drilling jig 28 (for example from a selection of standard drilling jigs which are configured for use with varying sizes of pipe 10 illustrated in Fig. 1) with a suitable predetermined axial longitudinal spacing between the securing portion 30 and the drill guide means 44, the drill guide means 44 is readily aligned with the annular void 27 so that the drill bit 46 can be readily guided into the annular void 27. In some embodiments, the drill guide means 44 is spaced circumferentially from the top dead centre of the securing portion 30 so that it can guide the drill bit 46 tangentially relative to the first pipe section 12.

In order to gain access to the annular void 27, the drilling jig 28 is used to drill a tangential through bore 48 in the end region 18 of the first pipe section 12.

In more detail and referring to Fig. 4, the drill bit 46 is used to initially drill partially through the end region 18 of the first pipe section 12, to form a blind hole 50. The blind hole 50 is then tapped using a suitable tapping tool 52 to form a thread and, following removal of the drilling jig 28, an injection facilitation member 54 in the form of a threaded injection nipple 56 is then screwed into the tapped blind hole 50. Following this, a drill bit 49, which may be the drill bit 46 or a drill bit having a different size, is inserted into the injection nipple 56 and further drilling of the end region 18 is carried out to extend the blind hole 50 and form the through bore 48, extending into the annular void 27. The injection nipple 56 includes a sealing member (not shown) which closes the aperture in the injection nipple 56 to prevent fluid flow therethrough but which is resiliently deformable and which therefore deforms upon insertion of the drill bit 49 to extend the blind hole 50. Once the blind hole 50 has been extended to form the through bore 48, the drill bit 49 is withdrawn and the sealing member resumes its original shape, thereby closing the aperture. The provision of such a sealing member is important since it prevents the escape of fluid from the interior 25 of the pipe 10 through the through bore 48 and into the atmosphere. For example, where the fluid carried by the pipe 10 is natural gas, any such escape could present a hazard, for example an explosion risk.

Referring now to Fig. 6, the next stage in the repair process is to locate a sealant guiding member 58 in the annular void 27. In more detail, the sealant guiding member 58 is in the form of a generally flexible braided hose 60 defining a hollow longitudinal passage 59 into which sealant can be injected from an open end 80 thereof, via the injection nipple 56. Due to the braided nature of the hose 60, which is illustrated diagrammatically in Fig. 6a, it is permeable and sealant injected into the hollow passage 59 can flow from the hollow passage 59 outwardly through permeable braided material to the exterior of the hose 60. This is discussed in further detail later in the specification.

Due to the flexible nature of the hose 60, it cannot be guided into the annular void on its own. Accordingly, an insertion member 62 in the form of an elongate, single-piece semi-rigid wire 64 is inserted into the hollow passage

59 in the hose 60 prior to insertion of the hose 60 into the annular void 27.

The wire 64 is inserted into the full length of the hose 60, a distal end 66 of the hose having been sealed, for example by crimping or otherwise, to provide an abutment for a corresponding distal end 67 of the wire 64.

After insertion of the wire 64 into the hose 60, the wire 64 (and consequently the hose 60) is pushed through the injection nipple 56 to insert it and the hose 60 into the annular void 27, at a position substantially adjacent to the gasket 22. This is illustrated most clearly in Fig. 7. Due to the inherent stiffness and malleability of the wire 64, it is deformed by the wall of the first and/or second pipe sections 12, 14 and tends to follow the circumferential path of the annular void 27. Insertion of the wire 64, and hence the hose 60, by pushing the wire 64 continues until the wire 64 and the hose 60 extend fully around the circumference of the annular void 27. During insertion of the wire 64 by pushing, there may be some stretching of the hose 60 which may facilitate insertion and increase the permeability of the hose 60 by increasing the separation of the braided material that is used to form the hose 60.

After the wire 64 and hose 60 have been fully inserted so that they both extend fully around the circumference of the annular void 27, the wire 64 is withdrawn from the hollow passage 59 inside the hose 60, as shown in Fig. 8, and the hose 60 remains in its inserted position, extending fully around the circumference of the annular void 27. It will be appreciated that the sealing member inside the injection nipple 56 co-operates with the hose 60 and/or the wire 64 in the same way that it co-operates with the drill bit 49 to prevent the escape of fluid flowing through the pipe 10.

Referring to Fig. 9, after removal of the wire 64 from the hose 60, an injection arrangement (not shown) including an injection hose 68 is attached to the injection nipple 56 to permit the injection of sealant into the hose 60 via the injection nipple 56. The viscosity of the sealant is selected so that when it is injected into the hose 60, it is guided by the hose 60 therealong, towards the distal end 66 thereof, without substantially permeating outwardly through the braided material of the hose 60. When the sealant reaches the distal end 66 of the hose 60, it tends to back fill the hose 60 in a direction towards the injection nipple 56, and there is a natural increase in pressure inside the hose 60 due to this back fill. As the pressure increases, the sealant tends to permeate through the braided material of the hose 60 and flows to the outer surface of the hose 60, to eventually completely cover the outer surface and form an annular sealant plug 70 in the region surrounding the hose 60, as best seen in Figs. 10 and 11. The annular sealant plug 70 extends fully around the circumference of the annular void 27 and contacts a radially inner surface 72 of the end region 18 of the first pipe section 12 and a radially outer surface 74 of the end region 20 of the second pipe section 14. Upon curing, the sealant plug 74 thereby forms a circumferentially extending impervious barrier, essentially in the form of a rubber O-ring, which prevents the escape of fluid flowing through the pipe 10 and thereby seals the leak in the pipe joint 16.

The pressure of the fluid flowing through the pipe 10 tends to prevent ' flow of the sealant into the interior 25 of the pipe 10 prior to curing of the sealant and also tends to cause some penetration of the uncured sealant into the decayed material from which the gasket 22 is formed. This penetration is advantageous as it causes some saturation (rehydration) of the gasket material which further improves the leak repair.

Following injection of the sealant, the through bore 48 may be plugged and the injection nipple 56 may be removed to complete the repair of the leaking pipe joint 16. The sealant used is typically a two-part thermosetting sealant.

There is thus described a method for sealing a leak in a pipe joint 16 which is significantly simpler than, and offers significant advantages over, known methods. In particular, unlike the method described in US 6634074, is does not require removal of existing gasket material to enable a leak to be repaired.

Figs. 12 to 28 show a second method of repairing a leak in the pipe joint 16. A drilling jig 100 is provided which has a mounting bolt 102 engageable in a blind threaded hole 104 provided in the circumferential lip 18a of the first pipe section 12. A locking nut 106 is threadably engaged on the bolt 102.

The jig 100 includes a slide member 108 which is an elongate strip with a central slot 110 through which the bolt 102 extends, with the nut 106 engageable against the slide member 108 to lock the slide member 108 in a required position. The left hand end as shown in Figs. 12 to 19 of the slot 110 is closed. Provided beneath the left hand end of the slide member 108 is a transverse bracing block 112 with two threaded steadying bars 114 which extend to the right as shown in Figs. 12 to 19 and threadably engage with the bracing block 112.

A fixing plate 116 is provided on the right hand end of the slide member

108, and extends vertically. A plurality of mounting holes 118 are provided through the fixing plate 116. A finger 120 extends transversely from the bottom of the fixing plate 116 at each end parallel to the slide member 108. A vertical steadying bar 122 extends through each finger 120 and is threadably engageable therewith.

A first drill guide 124 may be provided on the right hand face of the fixing plate 116 as shown in Fig. 12, and is mounted thereto by appropriate ones of the mounting holes 118 dependent on the size of the pipe sections 12, 14. The first drill guide 124 comprises a block 126 with a through hole 128 which can guide a drill. A mounting hole 130 extends transversely to the through hole 128 and can receive a bolt 132 threadably engageable with a respective one of the mounting holes 118.

A mounting slot 134 is also provided through the block 126 perpendicular to the through hole 128 and spaced from the mounting hole 130. A further bolt 136 is provided extendable through the slot 134, and can retain the block 126 with the through hole 128 at a required alignment, through threadable engagement with another of the mounting holes 118.

A second drill guide 138 is provided which is slidably mountable on the slide member 108 by a pair of bolts 140 each engageable with the slide member 108 respectively on either side of the slot 110. The drill guide 138 again includes a block 142 with a through hole 144. In this instance the through hole 144 is inclined gently downwards to the right as shown in Fig. 12.

In use, the drilling jig 100 can be mounted on the lip 18A with the bolt

102 extending through the slot 110 at the right hand end thereof as shown in

Fig. 12. A drill 146 is introduced into the through hole 144 in the second drill guide 138. Dependent on the size of the pipe sections 12, 14, adjustment of the height of the block 142 relative to the side member 108 may be made. The second drill guide 142 can now be slidably moved along the slide member 108 to provide a required place for the drill 146 to engage an outer part of the O-ring 26. As can be seen in Fig. 12 the drill 146 is inclined gently downwards. A hole 148 can then be drilled as shown in Fig. 13. A closure member 150 with a gland valve 152 is then knocked into the hole 148 to close same, as shown in Fig. 14, and a cap 154 can be fitted onto the distal end of the gland valve 152. The plate 116 and slide member 108 can then be rotated through 90° to the position shown in Fig. 14, to avoid obstructing further steps.

A feeler member 156 can then be used to locate the end of the second pipe member 14 and also the end of the gasket 22. The feeler member 56 comprises a sleeve 58 which slidably fits through the hole 148. An elongate feeler tool 160 extends through the sleeve 158. The tool is a length of wire with an inclined right hand end 162 as shown in Fig. 15 and a perpendicular left hand end 164.

By rotation and sliding of the tool 160 the "sweetspof 166 can be located at the left hand end of the region 20 of the second pipe length 12. The position of the far end of the pipe 12 can also be located with the tool right hand end 162 engaging thereover as shown in Fig. 17. With these measurements a correct position of the fixing plate 116 can be found and locked with the bolt 102 and nut 106 engaging through an appropriate place in the slot 110. Once the measurements have been made with the feeler member 156, the fixing plate 116 will be turned back through 90° to be transverse to the slide member as shown in Figs. 12 and 13.

The first drill guide 124 is then fitted onto the rear face of the fixing plate 116. The correct position of the fixing plate 116 having been chosen following the measurements made with the feeler member 56. The bolts 132,

136 will be left loose such that the block 126 can pivot about the bolt 132. A

U-shaped follower frame 168 is provided with the end of one side limb of the U locatable in the through hole 128, and the other side limb being longer, and at least at its end 169 being of the same diameter as a drill to be used. This other side limb is located against the second pipe section 14.

The bolt 136 is tightened to hold the block 126 in position such that drilling through the hole 128 will be tangential to the second pipe section 14. The follower member 168 can now be removed. A blind hole 170 is now drilled in the pipe section 12 by a drill 172 extending through the through hole 128 as shown in Fig. 24. An injection facilitation member 174 is then screwed into the blind hole 170. The member 174 has a gland valve 176 in it to prevent gas leakage thereoutof. The blind hole 170 is then further drilled right through the pipe section 12 to provide a tangential opening into the annular void 27.

A clearing wire (not shown) is then introduced through the member 174 to remove any debris and to measure the length around the void 27. Knowing the length of the void 27, a sealant guiding member 178 can be produced. Ends of this are shown in Figs. 26 and 27, this is in the form of a fibre glass hose 180 with a number of small holes 182 extending therethrough, with a greater concentration of holes 182 at a distal end of the hose 180. A mounting block 184 is provided on the proximal end of the hose and a guide wire 186 in the form of a strip of steel extends from the mounting block 184. Once the length of the aperture has been determined with the clearing wire, then the hose 180 can be cut to length, with the distal end of the guide wire 186 being overlapped as shown in Fig. 27.

The sealant guiding member 178 can be introduced into the annular void 27 through the injection facilitation member 174, until the mounting block 184 engages against a lip 188 in the member 178 as shown in Fig. 26. A sealant such as a low viscosity thermosetting polyurethane polymer can then be injected through a static mixer 190 through the member 178 into the guiding member 178. Principally the sealant will inflate the hose 180, but some sealant will pass out through the holes 182 into the void 27 to provide a completed repair as shown in Fig. 18 showing the hose 180 and sealant 192 that has passed out of the holes 182. This method is particularly suited for use with different sizes of joints which may for instance have different size pipes and different size lips on the pipes.

There is thus described a further method for sealing a leak in a pipe joint 16. In this instance the end of the second pipe section 14 can be accurately measured to ensure that a hole enters the void 27 at a correct location. This method also provides for ensuring that the hole into the void 27 enters at a correct tangential inclination.

If it is found for instance with the clearing wire that the wire cannot pass wholly around the void, a further hole could be drilled into the void 27 again tangentially relative to the second pipe section 14, but in an opposite direction. This will allow sealant guiding members to be inserted into the void from opposite directions. If necessary sealant can also be introduced through the hole 148.

Although embodiments of the invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that various modifications to the examples given may be made without departing from the scope of the present invention. For example, it is possible that the sealant guiding member 58 could be sufficiently rigid that the use of an insertion member 62 is not required to facilitate its insertion into the annular void 27. The sealant guiding member 62 may be formed of any suitable permeable material. The various bores and holes, and in particular the through bore 48, could be formed with the use of a drilling jig 28 having an alternative configuration, or possibly without the use of a drilling jig.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance, it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings, whether or not particular emphasis has been placed thereon.

Claims

1. A method for sealing a leak in a pipe joint between first and second pipe sections having an annular gasket at the joint, the gasket being located in an enlarged head at an end of the pipe section, which head receives an end of the second pipe section with the gasket provided around the second pipe section adjacent said end thereof, the method comprising inserting a sealant guiding member into an annular void adjacent to the gasket on an opposite side thereof to the remainder of the second pipe section and within the enlarged head, and thereafter injecting sealant into the sealant guiding member to provide a circumferential seal around the annular void and repair the leak.

2. A method according to claim 1 , in which the sealant guiding member is elongate.

3. A method according to claim 2, in which the sealant guiding member defines a hollow passage.

4. A method according to claim 3, in which injected sealant is guided by the hollow passage circumferentially around the annular void.

5. A method according to claim 4, in which injected sealant flows along the hollow passage during the step of injecting sealant into the sealant guiding member.

6. A method according to claim 5, in which the sealant guiding member comprises a flexible tube.

7. A method according to claim 6, in which the sealant guiding member comprises a hose.

8. A method according to claims 6 or 7, in which a plurality of holes are provided through the walls of the tube.

9. A method according to claim 8, in a greater concentration of holes is provided towards a distal end of the tube.

10. A method according to any of claims 1 to 5, in which the sealant guiding member is formed of a permeable material which permits sealant to flow therethrough.

11. A method according to claim 10 , in which the permeable material is a braided material.

12. A method according to claim 11 , in which the sealant guiding member comprises a braided hose.

13. A method according to any of claims 10 to 12, in which sealant flows through the permeable material during the step of injecting sealant into the sealant guiding member.

14. A method according to claim 13 when dependent on claim 2, in which the sealant flows from the hollow passage, outwardly through the guiding member during the step of injecting sealant into the sealant guiding member.

15. A method according to any of the preceding claims, in which the method comprises inserting an insertion member into the sealant guiding member prior to inserting the sealant guiding member into the annular void.

16. A method according to claim 15, in which the method comprises inserting the insertion member and the sealant guiding member into said annular void adjacent to the gasket, between the gasket and the internal region of the pipe.

17. A method according to claims 15 or 16 when dependent on claim 3, in which the method comprises inserting the insertion member into the hollow passage so that it extends fully through the insertion member, along the full length of the passage.

18. A method according to any of claims 15 to 17, in which the insertion member comprises a stiff elongate member.

19. A method according to claim 18, in which the insertion member has sufficient rigidity to allow it to be inserted circumferentially into the annular void and is sufficiently malleable to be deformed by the pipe wall so that it follows the circumferential path of the annular void.

20. A method according to any of claims 15 to 19, in which the insertion member comprises a wire.

21. A method according to any of claims 15 to 20, in which the method comprises removing the insertion member from the sealant guiding member prior to injecting the sealant into the sealant guiding member.

22. A method according to any of the preceding claims, in which the method comprises creating a through bore in the first pipe section, between the exterior of the pipe joint and the annular void, prior to inserting the sealant guiding member into the annular void.

23. A method according to claim 22, in which the . method comprises inserting the sealant guiding member through the created through bore into the annular void.

24. A method according to claims 22 or 23, in which the step of creating the through bore in the first pipe section comprises drilling a hole in the first pipe section.

25. A method according to claim 24, in which the step of drilling the hole comprises initially drilling a blind hole and thereafter extending the blind hole to form the through bore

26. A method according to any of claims 22 to 25, characterised in that the method comprises inserting an injection facilitation member into the through bore.

27. A method according to claim 26 when dependent on claim 25, in which the method comprises inserting the injection facilitation member into the blind hole before the blind hole is extended to form the through bore.

28. A method according to any of claims 22 to 27, in which the through bore is inclined away from a radial direction.

29. A method according to claim 28, in which the through bore is inclined and may be inclined so as to extend into the annular void but not into the second pipe section.

30. A method according to any of claims 22 to 29, in which the step of drilling the hole in the first pipe section to form the through bore comprises locating a drilling jig on the first pipe section.

31. A method according to any of claims 22 to 30, in which an elongate clearer member is introduced into the through hole to remove any debris, and to confirm if the annular void is clear to receive the insertion member around the whole circumference of the void.

32. A method according to claim 31 , in which a further through hole is formed extending in a different direction to the original through hole.

33. A method according to any of claims 22 to 32, in which the drilling jig defines a fixing aperture, and the method comprises forming a fixing hole in the first pipe section through the fixing aperture with the drilling jig secured to the first pipe section by suitable fastening means extending through the fixing aperture in the drilling jig.

34. A method according to any of claims 22 to 33, in which the drilling jig comprises a first drill guide for drilling the through bore at a required inclination.

35. A method according to claim 34, in which the first drill guide is spaced circumferentially from the fixing aperture and/or spaced longitudinally from the fixing aperture.

36. A method according to claims 34 or 35, in which the first drill guide is connected to a parallel follower, which follower can rest tangentially on the second pipe section spaced from the first pipe section, to provide a required alignment of the first drill guide.

37. A method according to any of claims 34 to 36, in which the first drill guide is pivotally mounted on the drilling jig, and lockable at a required orientation thereon.

38. A method according to any of claims 34 to 37, in which the first drill guide is movable in a longitudinal direction, and lockable in a required longitudinal position.

39. A method according to any of the preceding claims, in which the method includes the step of drilling through the gasket in a generally longitudinal direction to provide a gasket hole.

40. A method according to claim 39, in which a second drill guide is provided for drilling the hole through the gasket at a required inclination.

41. A method according to claim 40, in which the second drill guide is mounted on the drilling jig.

42. A method according to claim 41 , in which the second drill guide is movably mounted on the drilling jig, and lockable in a required position.

43. A method according to claim 42, in which the drilling jig includes an elongate guide extendable from the first pipe section parallel to and spaced from the second pipe section, with the second drill guide slidably mounted on the elongate guide.

44. A method according to claim 43, in which the second drill guide includes a guide passage inclined gently away from the elongate guide, such that movement of the second drill guide towards or away from the gasket, will determine the radial position of the hole being drilled through the gasket.

45. A method according to any of claims 39 to 44, in which a feeler member is extendable through the gasket hole to locate the position of the end of the second pipe section, and/or other features of the second pipe section and also the gasket.

46. A method according to claim 45, in which the feeler member is elongate with an inclined end.

47. A method according to claim 46, in which the feeler member is rotatable relative to the gasket hole to enable the features to be felt.

48. A method according to claim 47, in which the feeler member is mounted in a sleeve extendable through the gasket hole.

49. A method according to any of claims 31 to 48, in which the drilling jig includes a mounting plate, slidably movable relative to the fixing aperture.

50. A method according to claim 49, in which a plurality of holes or other formations are provided on the mounting plate to permit the first drill guide to be mounted thereon at a required position.

51. A method for sealing a leak in a pipe, the method being substantially as hereinbefore described and with reference to Figs. 1 to 11 of the accompanying drawings.

52. A method for sealing a leak in a pipe, the method being substantially as hereinbefore described and with reference to Fig. 1 and Figs. 12 to 26

53. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.