PIPE ADAPTOR AND METHOD

Abstract: An adaptor (14) to seal a liner pipe (12) inside a host pipe (10) comprises a flange (16) for sealing connection to one end of the liner pipe. A deformable sleeve (20) is on the flange. An expander element (24) is detachably connected to a placement device (28), and a cord (32) draws the expander element into the deformable sleeve to deform the sleeve into sealing engagement with the host pipe. A block (18, 40) prevents further movement of the expander element into the sleeve such that further drawing of the cord detaches the placement device from the expander element. In one embodiment, the placement device is connected to the expander element by a frangible link (26) which breaks when greater than a threshold drawing force is applied thereto. In another embodiment it comprises a pin (28') which can be drawn through the expander element once the expander element has expanded the sleeve.

Description: PIPE ADAPTOR AND METHOD The present invention relates to a pipe adaptor and to a method of relining a pipe employing such adaptor. In the gas and water industries, it is a frequently preferred option to reline an existing host pipe, for example a service pipe, rather than to excavate the existing pipe in order to replace it. This is particularly the case in the gas industry where reduction in diameter of the pipe is not usually a significant problem. Moreover, if the relining process can be conducted from a single access point considerable savings in time and effort, and hence cost, can be achieved. However, in this event, it is necessary to arrange for the end of the liner pipe which is inserted into the host pipe to be sealed against the host pipe so that there is no possibility of the fluid in the pipe leaking around the annular space between the liner and host pipes. Since the very reason that a host pipe is being relined is frequently because of an actual, suspected or possible leak in the host pipe, such a leak in the annular space would defeat that entire purpose. Thus, it is an object of the present invention to provide an adaptor which enables such sealing in a convenient and effective manner. In accordance with the present invention, there is provided an adaptor to seal a liner pipe inside a host pipe, the adaptor comprising: a flange for sealed connection to one end of the liner pipe; a deformable sleeve on the flange; an expander element having a bore therethrough; a placement device; and a cord, connectable to the placement device to draw the expander element into the deformable sleeve to deform the sleeve into sealing engagement with the host pipe. Preferably, a block is provided to prevent further movement of the expander element into the sleeve such that further drawing of the cord detaches the placement device from the expander element. Alternatively, some other means of disconnection of the placement device from the expander element is desirable and which enables the expander element to be detached in a most appropriate position inside the sleeve. Preferably, the placement device is connected to the expander element by a frangible link which breaks when greater than a threshold drawing force is applied thereto. The threshold value is sufficient to permit drawing of the expander element into the deformable sleeve but not past the block. Alternatively, the placement device comprises a pin which is larger than said bore, the expander element or pin deforming when greater than a threshold drawing force is applied to the cord and to permit passage of the pin through the expander element when the expander element contacts said block. The pin may have a shaft and a head, the shaft being smaller than said bore. The block preferably comprises the end of the liner pipe. The sleeve may surround the liner pipe, the liner pipe also being deformed on drawing of said expander element into the end of the liner pipe. In this event, the block preferably comprises a block flange on the expander element adapted to contact the end of the liner pipe. The cord may comprise a string, wire, chain or like flexible elongate element. The flange connecting the adaptor to the liner pipe may comprise a threaded tube screwed into the end of the liner pipe. Alternatively, the flange may be bonded or fused to the end of the sleeve. The deformable sleeve preferably comprises rubber or like elastomer. The flange may comprise a separate component to the sleeve which may be bonded or moulded to the flange. The liner pipe may comprise an axially compressible pipe, and in which event means are provided to prevent compression of the pipe during said drawing. Said means may comprise an axially incompressible element disposed along said liner pipe which is subsequently removed after said detachment of the placement device from the expander element. The host pipe may comprise a water or gas service or distribution pipe or any other pipe requiring relining. The present invention also provides a method of relining a host pipe, comprising: feeding a liner pipe from an access point in the host pipe, said liner pipe having on its end an adaptor as defined above, the cord extending internally of the liner pipe to its other end; stopping the feed when the adaptor end of the liner pipe has reached a desired limit; drawing the cord from the other end of the liner pipe to expand said sleeve into sealing engagement with the host pipe; detaching said placement device from said expander element; and, drawing said cord and placement device entirely from said other end of the liner pipe. Said method finds particular application in the relining of host pipes of diameter less than 350mm. Said liner pipe may be of polyethylene or other suitable material. Although the above embodiment utilises polyethylene liner pipes, the present invention is not limited thereto. An embodiment could equally well be realised in which the liner or host pipe would be metallic, for example, steel. The invention is further described hereinafter, by way of example, with reference to the accompanying drawings, in which: - Figures la to c are longitudinal sections through a host pipe and adaptor in accordance with a first embodiment of the present invention, Figure la showing a feed condition of a liner pipe with an adaptor on its end, Figure lb showing the adaptor expanded into sealing engagement with the host pipe, and Figure lc showing detachment of a placement device from the adaptor; Figures 2a to c are similar views to those of Figures la to c of a second embodiment of the present invention; and Figures 3a to c are similar views to those of Figures 1 and 2 but of a third embodiment of the present invention. Referring to Figures la to c, a host pipe 10 is shown in longitudinal section with a liner pipe 12 positioned therein. On the end of the liner pipe 12 is an adaptor 14. The adaptor 14 comprises a flange 16 fixed in the end 18 of the liner pipe 12. The flange 16 is secured to the liner pipe 12 by any convenient means, so long as the arrangement is secure and provides a fluid tight seal. The flange 16 may comprise a metal tube, for example a copper tube, fixed or screwed into the end of the liner pipe 12. Connected to the flange 16 is a deformable sleeve 20 which, in the event that the flange 16 is a metallic component, such as copper mentioned above, it is bonded to, or moulded on, the flange 16. Alternatively, the sleeve 20 and flange 16 may be integral components, and the flange 16 is, in this event, bonded or fused to the pipe liner 12. Both the flange 16 and the sleeve 20 have substantially the same internal bores 22. The adaptor further comprises an expander element 24 which may comprise a nylon, other plastics material component or a suitable material, for example, a metal. Connected by a frangible link 26 to the expander element 24 is a placement device 28. To the end 30 of the placement device 28 remote from the expander element 24 is connected a cord 32, which extends the full length of the liner pipe 12 and exits from its other end 35. The expander element 24 has an internal bore 34 substantially the same as the internal bore 22 of the sleeve 20 and flange 16. The expander element 24 has an external diameter substantially equal to the external diameter of the liner pipe 12. The method of application of the liner pipe 12 and adaptor 14 is as follows. With the adaptor in the position and condition on the end of the liner pipe 12 as shown in Figure la, the liner pipe 12 is inserted from an access point 37 of the host pipe 10. The liner pipe 12 is fed up the host pipe 10 until the adaptor 14 reaches a desired location. In a typical application, the host pipe 10 is a service pipe linking a distribution main to a domestic or commercial user. The access point 37 will typically comprise a branch adjacent a consumer meter which has temporarily been blocked and disconnected. The liner pipe 12 may have been inserted into the host pipe 10 through a stuffing box in order to maintain a seal against the atmosphere. In this event, a block is also provided at the open end 35 of the liner pipe 12. The desired position for the end 18 of the liner pipe 12 may be adjacent a junction of the host pipe 10 with a parent pipe having a larger diameter, for example a distribution main pipe. The relining of the pipe 10 is normally effected because the pipe 10 has corroded or cracked along its length and leaks from it are known, suspected or anticipated. Thus, if the relining process is to be effective, the annulus 38 surrounding the liner 12 and inside the pipe 10 must be sealed so that a fluid, for example gas under pressure at parent main end 39 cannot leak around the outside of the liner pipe 12. To this end is the adaptor 14 provided. When the pipe is in its desired location, therefore, the cord 32 is drawn from the open end 35 of the liner pipe 12 so that the expander element is drawn by the placement device 28 into the bore 22 of the deformable sleeve 20. For this purpose, a chamfered flange 40 on the expander element 24 cooperates with a similarly chamfered mouth 42 of the sleeve 20. On further drawing of the cord 32, the expander element enters into the bore 22 of the sleeve 20 deforming the sleeve 20 radially outwards so that it contacts the inside of the surface pipe 10, as shown in Figure lb. The expander element continues to be drawn through the sleeve 20 until shoulder 40 abuts end 18 of the liner pipe 12 (such abutment being, of course, through the material of the sleeve 20 at this point). The expander element cannot then be drawn further in the direction of the arrow A in Figure lb. Therefore, if further tension is applied to the cord 32, the frangible link 26 breaks, so that the placement device 28 becomes detached from the expander element 24, as shown in Figure lc. The placement device 28 can then be removed entirely from the liner pipe 12. A front end 44 of the expander 24 is preferably also chamfered to ease insertion of the pipe/adaptor 12,14 into the host pipe 10. Moreover, the expander element 24 is preferably somewhat shorter than the length of the sleeve 20, so that mouth 40 of the sleeve 20 recovers somewhat around the expander end 44 ensuring that the expander element 44 cannot inadvertently slip out of the sleeve 20. In this way, effective sealing of the liner 12 to the host pipe 10 is achieved. Turning to Figures 2a to c, a different embodiment of the present invention is illustrated. Like components are given the same reference numerals as employed in Figures la to c, except that any differences therebetween are indicated by a prime. In Figures 2a to c, adaptor 14' has an expander element 24 ' which differs from expander 24 of Figure 1 in that placement device 28 ' is not integral therewith but is a separate component. Here, placement device 28' comprises a pin 50 having a head 52. The pin 50 is a sliding fit inside the bore 34 of the expander 24'. Otherwise, the arrangement is very similar to the arrangement of Figure 1. However, when chamfered shoulder 40 of the expander element 24' contacts end 18 of the liner pipe 12, and prevents further movement of the expander 24 ' , instead of the placement device 28 ' becoming detached from the expander 24', the pin head 52, which previously had drawn the expander into the sleeve 20, deforms the expander element 24, serving further to increase its bore diameter as it is drawn through, and eventually released from, the expander 24'. Needless to say, the force required to pull the pin head 52 through the expander element 24 ' is arranged to be greater than the force required to draw the expander element 24' into the deformable sleeve 20. Moreover, if preferred, it would be equally possible to arrange for the pin head 52 to deform as it is drawn through the bore 34 of expander element 24 * . Finally, turning to Figures 3a to c, a further embodiment of the present invention is shown. Here, adaptor 14" differs from that of Figure 2 in that its deformable sleeve 20' is disposed around the end 18 of the liner pipe 12. In this event, the flange 16 is indistinct from the sleeve 20' and integral therewith. As will be explained hereinafter, the flange 16 is, in this embodiment, deformable, like the sleeve 20', and therefore does not comprise a metal tube, such as a copper tube. The sleeve 20' is thus sealed directly on the end of the pipe 12, and does not require any absolute bonding or other securing thereon, for reasons which are explained further below. In this embodiment, the expander 24", when it is drawn into the sleeve 20 ' , is actually drawn into the end 18 of the pipe 12. It is therefore necessary, in this embodiment, that the liner pipe 12 be also of deformable plastics material, such as polyethylene. Instead of shoulder 40 of the expander element 24" providing the block in this embodiment (the shoulder 40 here in fact easing entry of the expander 24 ' into the pipe 12) a block flange 54 is provided. The block flange 54 engages the ends 18 of the pipe and prevents further drawing of the expander element 24" into the pipe. As shown in Figure 3b, when the block flange 54 contacts the pipe end 18, it is at this point that the pin head 52 of the placement device 28 ' commences to deform the expander element 24" to further compress the pipe 12 and sleeve 20' against the bore of the host pipe 10 and simultaneously release the placement device 28' into the liner as shown in Figure 3c. In the above described embodiments of the present invention, the liner pipe is a polyethylene pipe or similar which can be fed down host pipes, so long as the diameter of the liner pipe is smaller than the internal diameter of the host pipe, so that the liner pipe is sufficiently flexible to negotiate bends in the host pipe. The polyethylene pipe as shown in the drawings cannot easily manage tight bends and can often only be employed to line pipes if the host pipe is substantially straight. Consequently, the ability of the liner pipe to negotiate elbows, bends or other special fittings which are an integral part of the host pipe, is restricted only be the degree of flexibility of the liner pipe. A stiffener is particularly important where an adaptor in accordance with the present invention is employed. In this event, a reactance against the drawing of the expander element into the sleeve is required, and which such stiffener provides. The stiffener tube may have a flared end which may bear against a trailing edge of the flange 16. However, this depends on the form of connection between the adaptor and the liner pipe tube. It is feasible that the adaptor is fused to the end of liner pipe, but which ever method is employed, it is necessary to provide some releasable connection between the stiffener and the end of the liner pipe for the purpose of preventing compression thereof. Typically, the diameters of pipes which can be relined using the present invention can vary from between 20mm to 350mm. An embodiment of the invention may comprise circular guide fins disposed on the outer surface of the expander element or on the liner pipe. The guide fins ensure that the liner pipe or expander element is centrally disposed within the host pipe.

Claims: CLAIMS 1. An adaptor to seal a liner pipe inside a host pipe, the adaptor comprising: a flange for sealing connection to one end of the liner pipe; a deformable sleeve on the flange; an expander element having a bore there through; a placement device; and a cord, connectable to the placement device to draw the expander element into the deformable sleeve to deform the sleeve into sealing engagement with the service pipe. 2-.- An adaptor as claimed in claim 1, further comprising a block to prevent further movement of the expander element into the sleeve such that further drawing of the cord detaches the placement device from the expander element. 3. An adaptor as claimed in claim 1 or 2, in which the placement device is connected to the expander element by a frangible link which breaks when greater than a threshold drawing force is applied thereto. 4. An adaptor as claimed in claim 1 or 2, in which the placement device comprises a pin which is larger than said bore, the expander element or pin deforming to permit passage of the pin through the expander element when the expander element contacts said block. 5. An adaptor as claimed in claim 4, in which the pin has a shaft and a head, the shaft being smaller than said bore. 6. An adaptor as claimed in any preceding claim, in which the block comprises the end of the liner pipe. 7. An adaptor as claimed in any preceding claim, in which the cord comprises a string, wire, chain or like flexible elongate element. 8. An adaptor as claimed in any preceding claim, in which the flange connecting the adaptor to the liner pipe comprises a tube fixed to the end of the liner pipe. 9. An adaptor as claimed in claim 8, wherein the tube is threaded and is screwed onto or into the end of the liner pipe. 10. An adaptor as claimed in any of claims 1 to 7, in which the flange is bonded, fused or mechanically attached to the end of the sleeve. 11. An adaptor as claimed in any preceding claim in which the deformable sleeve comprises rubber, elastomer or other deformable material. 12. An adaptor as claimed in any preceding claim, in which the flange comprises a separate component to the sleeve which is bonded, moulded or affixed to the flange. 13. An adaptor as claimed in any preceding claim, in which the liner pipe comprises an axially compressible pipe and in which means are provided to prevent compression of the pipe during said drawing. 14. An adaptor as claimed in claim 12, in which said means comprises an axially incompressible element disposed along said liner pipe and which is removed after said detachment of the placement device from the expander element . 15. An adaptor as claimed in any preceding claim, in which the sleeve surrounds the liner pipe, the pipe also being deformed on drawing of said expander element into the end of the liner pipe. 16. An adaptor as claimed in claim 14, in which the block comprises a block flange on the expander element adapted to contact the end of the liner pipe. 17. An adaptor as claimed in any preceding claim, in which the host pipe comprises a water or gas service or distribution pipe. 18. A method of relining a host pipe, comprising: feeding a liner pipe from an access point in the host pipe, said liner pipe having on its end an adaptor as claimed in any preceding claim, the cord extending internally of the liner pipe to its other end; stopping the feed when the adaptor end of the liner pipe has reached a desired limit; drawing the cord from the other end of the liner pipe to expand said sleeve into sealing engagement with the service pipe; detaching said placement device from said expander element; and, drawing said cord and placement device entirely from said other end of the liner pipe. 19. An adaptor for a host pipe, substantially as hereinbefore described with reference to Figure 1, 2 or 3 of the accompanying drawings. 20. A method of relining a host pipe, substantially as hereinbefore described with reference to Figures 1, 2 or 3 of the accompanying drawings

Inventors: SAUNDERS ANTHONY CHARLES PATRI, SCOTT PETER SIDNEY, SAUNDERS, ANTHONY, CHARLES, PATRICK, SCOTT, PETER, SIDNEY
Applicants: SAUNDERS ANTHONY CHARLES PATRI, SCOTT PETER SIDNEY, SYNTHOTECH SPECIAL PRODUCTS LI, SAUNDERS, ANTHONY, CHARLES, PATRICK, SCOTT, PETER, SIDNEY, SYNTHOTECH SPECIAL PRODUCTS LIMITED
Application year: 1999
Main classification: F16L55
IPC codes: F16L55