GB2228777A

GB2228777A - Service conduits

Info

Publication number: GB2228777A
Application number: GB9003182A
Authority: GB
Inventors: John Gilbert
Original assignee: Thames Water Utilities Ltd
Current assignee: Thames Water Utilities Ltd
Priority date: 1989-02-14
Filing date: 1990-02-13
Publication date: 1990-09-05
Anticipated expiration: 2010-02-13
Also published as: GB9003182D0; GB8903288D0; GB2228777B

Abstract

An elongate flexible auxiliary member such as a communications cable 1 or pipe line is inserted in a live subterranean water or gas pipe 2 without the need to provide a major excavation from the surface 3 down to the pipe 2, which is tapped in situ from the surface 3 using apparatus 4. The tapping of the pipe 2 comprises making a small excavation 5 and accurately positioning a sleeve 6 to extend from the pipe 2 to ground level 3. This is achieved by one end of the sleeve 6 being shaped to fit snugly on the pipe 2 and in-filling around the outside of the sleeve 6. A guide 9 is tapped into the pipe 2. The member 1 is fed through a seal 19 which may be urged against the member 1 by pressure water fed into a manifold 18 via an inlet 22. The telescopic guide 9 is provided with an articulated bend limiter 24 for the member 1. The limiter 24 is orientated by the water flow 'X' and a limiter end member 25a is vertically aligned by a key (27, Fig. 2 not shown) and keyway (28) on a mounting member (30) of a ferrule secured in the tapped pipe wall. <IMAGE>

Description

SERVICE CONDUITS The invention relates to service conduits, for example a water pipe which carries water supply underground in say a town.

Such pipes often are linked up to provide an extensive network which is often strategically placed in that it can be used to carry auxiliary members or components such as communication cables.

Indeed, it has been realised that such cables can be located in the pipes and distributed as required over the network. The problem is that such cables need to be relatively easily and quickly installed in the pipes without major excavation work. This problem has been recognised, but the solution has not been one which allows for the installation of an auxiliary member such as a communication cable in a pipe whilst the pipe carries water under pressure and without suspending that pressure.

It is accordingly an object of the invention to seek to mitigate these disadvantages.

According to one aspect of the invention there is provided a method of inserting an elongate flexible auxiliary member in an existing service pipe comprising the steps of tapping the pipe, mounting a guide on the tapped pipe, and feeding a desired length of the elongate flexible auxiliary member along the guide through the tapping into the pipe.

The method may include the step of sealing a tapped pipe system against escape of fluid, for example by sealing the tapping before mounting the guide on the tapping.

The method may comprise the step of providing a cylindrical guide and may include the step of mounting a sealing valve device on an end of the guide remote from the tapping.

There may be the step of connecting a pressure resistor device to the sealing valve device.

The method may include the step of passing a bend restrictor along the guide through the tapping into the pipe to restrict bending of the auxiliary member at its entry into the pipe.

The method may include the step of sealing the guide against escape of fluid by mounting a seal housing internally of the guide.

The method may include the step of adjusting the length of the guide, which may be adjustable telescopically.

There may be the step of operating the seal device after inserting the seal housing therethrough into the guide.

The step of operating of the seal device may comprise expanding part thereof to seal against the auxiliary member.

The method may include the step of making a further tapping in the pipe, mounting a further guide at the further tapping, and extracting the auxiliary member from the pipe through the further tapping.

The pipe may be a subterranean pipe and the method may include an initial step of excavating a hole to an external surface of the pipe.

The excavating step may be by vacuum excavation.

The auxiliary member may be a communication cable and the fluid may be water the flow of which is not suspended during the insertion of the cable, which is drawn along the pipe a desired distance by the flow of water through the pipe.

The cable may comprise a drogue on which the water may act to draw the cable through the pipe.

According to a second aspect of the invention there is provided apparatus for inserting an elongate flexible auxiliary member in an existing service pipe carrying a fluid, comprising means for tapping a pipe, a guide for mounting on the pipe adjacent the tapping, and means to feed an auxiliary member along the guide through the tapping in to the pipe.

The guide may comprise a cylindrical member adapted to be mounted at one end at or adjacent the tapping and adapted for releasably mounting a seal means at an end opposite the one end.

The member may be adapted by a flange at the opposite end for mounting a flange of a seal means.

The seal means may have a through bore defined by a boundary wall through which the elongate auxiliary member can be passed which wall is movable to reduce the bore and seal round the member in use.

The boundary wall may be expansible.

The boundary wall may comprise an elastic sleeve.

The sleeve may be mounted in a relatively rigid body of the seal means so that there is a space between the sleeve and body into which a medium may be passed for expanding the sleeve through an inlet port therefor.

The sleeve may have reinforcement, which may comprise spaced apart KEVLAR reinforcements.

The cylindrical member may be adjustable in length.

The cylindrical member may comprise a plurality of telescopic parts.

There may be sealing means between overlapping parts of the telescopic parts.

The sealing means may comprise an 'O' ring seal set in a circumferential groove in one part.

The apparatus may include a device to restrict bending of an elongate member in the pipe.

The device may comprise a plurality of articulated members arranged in series along a curve in one plane.

The or each member may have an outer tapered surface, the members being arranged so that the device has an overall taper from one end to the other.

There may be a pressure resistor adapted for mounting on the guide to resist pressure of fluid in the pipe in use, whereby to obviate or reduce leakage.

According to a third aspect of the invention there is provided a service pipe in combination with apparatus as hereinbefore described.

The service pipe may be a subterranean service pipe carrying water, and may include a communication cable inserted therein through the apparatus.

There may be aadditional apparatus spaced from the first-mentioned apparatus along the length of the pipe, through which the inserted cable exits the pipe.

According to a third aspect of the invention there is provided a seal means for sealing a volume around the exterior of a member in the seal means, comprising a bore through which the member can pass and means to embrace the part of the member in the bore to prevent or hinder passage of fluid from one end of the bore to the other.

The embracing means may comprise an expansible member, which itself may comprise a resilient sleeve.

The resilient sleeve may be mounted spaced from a body of the seal means and defining with the body, preferably cylindrical, a manifold for expansion medium.

The sleeve may be reinforced with reinforcement, such as spaced reinforcing fingers, which may comprise KEVLAR.

The fingers may be located circumferentially of the sleeve at both ends thereof.

The body may include means whereby the seal may be mounted with another member.

The mounting means may comprise end flanges.

According to a fifth aspect, the invention provides a communications system including at least one cable therefor deployed in a pipe b a method or using apparatus, or in a pipe, as hereinbefore defined.

A method and apparatus embodying the invention and hereinafter described, by way of example, with reference to the accompanying drawings.

Fig. 1 is an exploded perspective view of a water pipe including an internal auxiliary member in the form of a communications cable installed using a method and apparatus according to the invention; Fig. 2 is a perspective view of part of the apparatus of Fig. 1, to a larger scale than that Figure; Fig. 3 is a perspective view of a yet further part of the apparatus of Fig. 1, and to a larger scale; and Fig. 4 is an exploded perspective view of a seal means.

Referring to the drawings an elongate flexible auxiliary member such as a communications cable 1 is inserted in a subterranean water pipe 2 without the need to provide a major excavation from the surface 3 down to the pipe 2, which is tapped in situ from the surface 3 using apparatus 4 embodying the invention. The tapping of the pipe follows a sequence; the water pipe is detected and a small excavation 5 is made to a depth to expose the upper half thereof.

The next step involves accurately positioning a liner 6 to extend from the pipe 2 to ground level 3, the liner 6 being radial of the pipe and perpendicular to the longitudinal axis of the pipe. This is achieved by one end of the liner being shaped to fit snugly on the pipe 2. The end of the liner is profiled so that, when it is seated on the pipe it is automatically 'aligned'. In-filling is then completed around the outside of the liner. In this way, the liner 6 is secured in alignment relative to the pipe.

The area of the main lying within the liner is cleaned to ensure a good adhesion by a saddle 7 which, fitting snugly in the liner, is placed on, and secured by adhesive to, the pipe. The liner ensures accurate positioning of the saddle. The saddle 7 includes a control aperture through which the tapping is to be made into the pipe. A valve member & is fitted to the saddle. In order to ensure satisfactory securement of the saddle to the main, it is pressure tested. The pipe is then drilled and tapped by a tool attached to the saddle, so is thus held in alignment so that the tapping so made is in alignment. The treppaned section of the pipe is retained by the drill tool.

After removal of the drill tool, a ferrule is fitted into the tapping using a further tool.

The ferrule is screwed to the tapping in the wall of the pipe and is tubular with a removable plug to allow access to the interior of the pipe. The ferrule may include a bend limiter.

Having tapped as described with the manually operable valve 8 in place, a guide in the form of a cylindrical sleeve 9 is mounted on top of the manual valve 8. The sleeve 9 is of adjustable length being formed of a plurality in this case two, of telescoping ports 9' and 9 ", the end of the inner part 9' having two grooves 10 in each of which there is seated an O-ring 11 which bears on the inner surface of the outer part 9 " to produce a seal.The upper (as viewed! end of the outer part 9 " has mounting means in the form of a flange 12 which receives a similar mounting flange 13 of a seal means 14 the flanges 12 and 13 having through bores 15 whereby the seal means may be removably mounted on the guide by nuts and bolts (not shown). The seal means 14 (Fig. 4) has an opposite flange 16 for connection with a pressure resistor (not shown) and a metal body 17 of cylindrical form connecting the flanges 13, 16. Secured between the flanges 13, 16 and spaced from the body 17 to form a space or manifold 1R there is an expansible member in the form of an elastic compression sleeve 19 which has reinforcements in the form of spaced fingers 20 of KEVLAR (Registered Trademark) along the upper and lower edges (as viewed).The sleeve 19 lines a through bore 21 through which the cable 1 can be passed. In order to seal the volume round the cable 1 against liquid flow, the sleeve 19 is expanded into the bore 21 to embrace the cable 1 by passing fluid such as water under pressure into the manifold 18 through an inlet port 22. The sleeve 19 embraces the cable 1 firmly but gently so that it is not damaged and its communications carrying integrity is not disrupted. Aleanwhile, the whole of the bore 12 is obturated by the sleeve 19. When sealing is complete, or the cable needs to be moved or the bore 21 is required for passage of other equipment towards the pipe 2, the pressurized water is released through outlet port 23 so that the sleeve 19 returns to its relaxed or unexpanded state. The sleeve 19 thus acts as a valve as well as a seal.In order to prevent kinking or bending of the cable 1 in situ in the pipe 2, which bending or kinking could impair the communication ability of the cable, a device in the form of a bend limiter or restrictor 24 is installed below the tapping in the pipe to extend therefrom into the pipe 2. The bend restrictor 24 comprises a plurality of tubular members 25 which are interlinked and articulated in series, the outer surface of each member being tapered and the arrangement being such that the bend restrictor overall tapers from the end adjacent the tapping to the free end where the cable 1 emerges into the pipe 2.This arrangement is such that when the bend restrictor 24 is fed into the pipe 2, the pressure of water flowing in the direction of arrow 'X' forms the restrictor 24 into a smooth curve pointing in the direction of flow 'X' so that when the cable 1 is fed therethrough, it is drawn by the flow in the direction thereof for which purpose it carries at its nose and/or along its length a drogue or drogues (not shown) which are deployed when the cable 1 leaves the bend restrictor 24 at its free end and is acted on by the flow to draw the cable 1 along the pipe 2. The member 25a forming the end of the bend restrictor 24 mounted in the tapping has a locating collar 26 with a key or guide 27 which locates in a key-way or guide channel 28 in an upstanding ring 29 of a mounting member 30 secured to the ferrule in the tapping. The key 24 and keyway 28 engage when member 25a is rotated for correct vertical alignment, and a locking ring 31 is then screwed down to hold the locating collar 26 in position, there being slots 32 for a suitable turning tool (not shown) to be applied to effect screwing down.

In use to install a communications cable 1 in the pipe 2 while water is still flowing (arrow 'X') under pressure therethrough, the subterranean pipe 1 is located and tapped as described hereinbefore.

The valve 8 is turned by handle 33 to seal flow out of the pipe through the tapping when the plug in the ferrule is removed and the telescopic cylindrical guide 9 is installed from the surface 3 being adjusted telescopically to the correct length depending on the depth of the pipe below the surface. The seal means 11 is mounted in the flange 12, and a pressure resistor (not shown) is mounted on the flange 16 of the seal means 14.Then, with the valve 8 open and the pressure resistor operating to resist pressure of the water and thence to prevent flow of water to the surface, the bend restrictor 24 is inserted from the surface and received in position at the tapping using the locating collar 26 and locking ring 31 as described previously. The cable 1 is then fed through the seal means 14, down the guide 9 and through the bend restrictor 24 into the pipe 2 where it is carried along by the pressure flow as described previously. The cable 1 is deployed the required distance by feeding the required length.

The sleeve 19 of the seal means is expanded to embrace the cable 1 and cut off flow and the pressure resistor is inoperative. A chevron kind of seal 34 is then installed through the seal means 14, the chevron seal being pushed down the guide 9 to a collar 35, the seal acting all the time to seal the interior of guide against flow of water to the surface, the seal having a bore 36 in a body 37 through which the cable 1 passes without damage. The seal means 14 is then removed from the flange 12 after deflating the sleeve 19 by releasing pressurized water from the manifold 18 through the outlet port 23. A cover 37 at the surface 3 is then placed in position to close the excavation 5.It will be understood that the cable 1 may be brought to the surface 3 through a similar apparatus 4 used as an exit apparatus spaced along the length of the pipe 2 from the entry apparatus shown.

Thus it will also be understood that the method and apparatus of the invention provide an interface between an in situ tapping of the pipe in an excavation which is not big enough to take an operative, and a cable deploying method and cable retrieval method.

The invention therefore extends to a communications system in which a cable network is deployed in subterranean pipes. Moreover although a water pipe 2 has been referred to, the pipe could carry other services, such as gas, and indeed the method and apparatus of the invention could be used to tap and deploy in pipes in use which are not underground but at the surface or suspended or supported thereover. In such cases, it is merely necessary to omit the excavation steps mentioned herein with reference to the drawings. Finally, although communication cables have been described, other auxiliary equipment such as a pipe or liner of smaller diamater than the pipe 2 could be deployed therein using the method and apparatus of the invention.

Claims

1. A method of inserting an elongate flexible auxiliary member in an existing service pipe, comprising the steps of tapping the pipe, mounting a guide on the tapped pipe, and feeding a desired length of the elongate flexible auxiliary member along the guide through the tapping into the pipe.

2. A method according to claim 1, including the step of sealing a tapped pipe system against escape of fluid.

3. A method according to claim 2, including the step of sealing the tapping before mounting the guide on the tapping.

4. A method according to claim 3, comprising the step of providing a cylindrical guide and including the step of mounting a sealing valve device on an end of the guide remote from the tapping.

5. A method according to claim 4, including the step of connecting a pressure resistor device to the sealing valve device.

6. A method according to any preceding claim, including the step of passing a bend restrictor along the guide through the tapping into the pipe to restrict bending of the auxiliary member at its entry into the pipe.

7. A method according to claim 6, including the step of sealing the guide against escape of fluid by mounting a seal housing internally of the guide.

8. A method according to any preceding claim, including the step of adjusting the length of the guide.

9. A method according to claim s, the guide being adjustable telescopically.

10. A method according to claim 9, including the step of operating the seal device after inserting the seal housing therethrough into the guide.

11. A method according to claim 10, the step of operating of the seal device comprising expanding part thereof to seal against the auxiliary member.

12. A method according to any preceding claim, including the step of making a further tapping in the pipe, mounting a further guide at the further tapping, and extracting the auxiliary member from the pipe through the further tapping.

13. A method according to any preceding claim, in which the pipe is a subterranean pipe and the method includes an initial step of excavating a hole to an external surface of the pipe.

14. A method according to claim 13, the excavating step being by vacuum excavation.

15. A method according to any preceding claim, the auxiliary member being a communications cable and the fluid being water the flow of which is not suspended during the insertion of the cable, which is drawn along the pipe a desired distance by the flow of water through the pipe.

16. A method according to claim 15, the cable comprising a drogue on which the water acts to draw the cable through the pipe.

17. A method of inserting an elongate flexible auxiliary member in an existing service pipe carrying fluid, substantially as hereinbefore described with reference to the accompanying drawings.

18. Apparatus for inserting an elongate flexible auxiliary member in an existing service pipe carrying a fluid, comprising means for tapping a pipe, a guide for mounting on the pipe adjacent the tapping, and means to feed an auxiliary member along the guide through the tapping into the pipe.

19. Apparatus according to claim 18, the guide comprising a cylindrical member adapted to be mounted at one end at or adjacent the tapping and adapted for releasably mounting a seal means at an end opposite the one end.

20. Apparatus according to claim 19, the member being adapted by a flange at the opposite end for mounting a flange of a seal means.

21. Apparatus according to claim 20, the seal means having a bore through which the elongate auxiliary member defined by a boundary wall can be passed which is movable to reduce the bore and seal round the member in use.

22. Apparatus according to claim 21, the boundary wall being expansible.

23. Apparatus according to claim 22, the boundary wall comprising an elastic sleeve.

24. Apparatus according to claim 23, the sleeve being mounted in a relatively rigid body of the seal means so that there is a space between the sleeve and body into which an expansible medium is passed for expanding the sleeve through an inlet port therefor.

25. Apparatus according to claim 24, the sleeve having reinforcement.

26. Apparatus according to claim 25, the reinforcement comprising spaced apart KEVLAR reinforcements.

27. Apparatus according to any of claims 19 to 26, the cylindrical member being adjustable in length.

28. Apparatus according to claim 27, the cylindrical member comprising a plurality of telescopic parts.

29. Apparatus according to claim 28, there being sealing means between overlapping parts of the telescopic parts.

30. Apparatus according to claim 29, the sealing means comprising an O-ring seal set in a circumferential groove in one part.

31. Apparatus according to any one of claims 18 to 30, including a device to restrict bending of an elongate member in the pipe.

32. Apparatus according to claim 31, the device comprising a plurality of articulated members arranged in series along a curve in one plane.

33. Apparatus according to claim 32, the or each member having an outer tapered surface, the members being arranged so that the device has an overall taper from one end to the other.

34. Apparatus according to any of claims 18 to 33, including a pressure resistor adapted for mounting on the guide to resist pressure of fluid in the pipe in use, whereby to obviate or reduce leakage.

35. Apparatus for inserting an elongate flexible auxiliary member in an existing service pipe, substantially as hereinbefore described with reference to the accompanying drawings.

36. A service pipe, in combination with apparatus according to any of claims 18 to 35.

37. A service pipe according to claim 36, which is a subterranean service pipe carrying water.

38. A service pipe according to claim 37, including a comnunication cable inserted thereby through the apparatus.

39. A service pipe according to claim 38, including additional apparatus spaced from the first-mentioned apparatus along the length of the pipe, through which the inserted cable exits the pipe.

40. A service pipe, substantially as hereinbefore described with reference to Fig. 1 of the accompanying drawings.

41. A seal means for sealing a volume around the exterior of a member in the seal means, comprising a bore through which the member can pass and means to embrace the part of the member in the bore to prevent or hinder passage of fluid from one end of the bore to the other.

42. A seal means according to claim 41, the embracing means comprising an expansible member.

43. A seal means according to claim 42, the expansible member comprising a resilient sleeve.

44. A seal means according to claim 43, the resilient sleeve being mounted spaced from a body of the seal means and defining with the body a manifold for expansion medium.

45. A seal means according to claim 44, the body being cylindrical.

46. A seal means according to any of claims 43 to 45, the sleeve being reinforced with reinforcement.

47. A seal means according to claim 46, the reinforcement comprising spaced reinforcing fingers.

48. A seal means according to claim 47, the fingers comprising KEVLAR.

49. A seal means according to claim 47 or 48, the fingers being located circumferentially of the sleeve at both ends thereof.

50. A seal means according to claims 44 to 49, the body including means whereby the seal may be mounted with another member.

51. A seal means according to claim 50, the mounting means comprising end flanges.

52. A seal means for sealing a volume around the exterior of a member in the seal, substantially as hereinbefore described with reference to Fig. 4 of the accompanying drawings.

53. A communications system including at least one cable therefor deployed in a pipe by a method or using apparatus or in a pipe according to any of claims 1 to 17 or 18 to 35 or 36 to 40.