WO1992010701A1

WO1992010701A1 - Water distribution systems

Info

Publication number: WO1992010701A1
Application number: PCT/GB1991/002103
Authority: WO
Inventors: John Colin Grace
Original assignee: Tate Pipe Lining Processes Limited
Priority date: 1990-12-05
Filing date: 1991-11-27
Publication date: 1992-06-25
Also published as: GB9026450D0; AU9043191A

Abstract

Underground piping (21) is removed by inserting a wire rope (27) therethrough with or without a spinning action, bonding the piping and inserted wire rope together to form an integrated assembly by inserting a settable bonding medium (49) in the annular gap (37) therebetween, and extracting the integrated assembly by pulling and/or pushing same out of the earth strata. The extracted piping can be replaced by fresh piping by coupling the latter to the trailing end of the integrated assembly. The preferred application is the replacement of underground lead or galvanised piping by plastic piping.

Description

WATER DISTRIBUTION SYSTEMS

This invention relates to water distribution systems and in particular to the removal and replacement of underground piping, especially but not exclusively lead or galvanised piping, connecting a main water supply pipe or conduit to domestic, industrial and other premises.

In a typical domestic water distribution system where houses are arranged along the opposite sides of a street the main water supply pipe lies under the thoroughfare, nearer one side of the street than the other (although not necessarily so) and laterally-extending supply pipes, usually lead pipes, connect the main water supply pipe or conduit to each house in the street.

Water distribution through lead piping is no longer acceptable for health risk and environmental reasons with the added incentive of an E.C. directive requiring their replacement by plastic piping (M.D.P.E.).

In the case of galvanised piping health risks and adverse environmental factors can arise from corrosion of the piping and replacement of such piping by plastic piping (M.D.P.E.) is also desirable.

It is to be clearly understood, however, that the present invention is applicable to the replacement of underground piping whatever its constitution by fresh piping whatever its constitution.

It is to be understood also that the present invention is equally applicable to the removal of underground piping without the replacement thereby of fresh piping.

For the sake of convenience, however, we shall hereinafter refer in the description and accompanying claims, where appropriate, to "lead" pipe and "plastic" pipe with the clear understanding that such references are merely exemplary and non-restrictive to the scope of the invention as claimed.

Conventionally, lateral lead pipes are extracted and replaced either by "trenching", i.e. digging down to expose same and cutting same out and replacing by plastic pipes, or by "moling" i.e. using percussive moles to bore alongside the existing lateral lead pipes while dragging in replacement plastic pipes, or by a combination of both "trenching" and "moling".

Percussive moles, in addition to being expensive pieces of equipment, can be erratic and consequently may track off the desired path and either surface where they are not wanted (upward tracking) with consequent thoroughfare damage, or travel underground downwardly and/or laterally off the desired path which requires cessation of the replacement operation until they are found and dug out.

"Moling" is thus a comparatively expensive operation and can involve time-consuming and expensive downtime and surface damage repair and also damage to the other underground services.

"Trenching" is time consuming, labour intensive and costly due to the requirement of removal of extracted thoroughfare material and making up the trench (stone infill, etc.) to local authority requirements. It is an object of the present invention to obviate or mitigate all of the aforesaid disadvantages by the method and apparatus of the present invention used for underground pipe replacement.

According to the present invention underground pipe is rendered suitable for extraction by pulling and/or pushing by threading an elongate support or carrier through the length of an underground pipe leaving an annular gap therebetween, filling the annular gap with a settable fluent bonding medium, and permitting the latter to set or cure to bind the pipe and the elongate support or carrier together to form an integrated assembly for removal from underground by pulling and/or pushing.

Thereafter, in accordance with this invention, the integrated assembly of underground pipe, elongate support or carrier and bonding medium can be pulled out of the surrounding earth strata.

It may alternatively be pushed out or be removed by a combination of pulling and pushing.

The elongate support or carrier is preferably a wire rope. The bonding medium is preferably a cementitious material, i.e. a grout but may, inter alia, be a settable resinous material.

In accordance with the present invention the underground pipe is replaced by a fresh pipe by coupling or clamping the latter to the end of the underground pipe remote from the end of the latter to which the pulling action is applied whereby the fresh pipe is pulled into the earth strata trailing the aforesaid integrated assembly during its extraction to replace the lead pipe.

Preferably, the coupling joining the underground pipe to the fresh pipe is of such a configuration, preferably conical, that the hole or passage occupied by the underground pipe is upsized as the underground pipe is extracted to facilitate entry of the fresh pipe.

The pulling action may, inter alia, be effected by a hollow or other fluid-operated ram with which is preferably associated a chopping device to cut the extracted integrated assembly into pieces of manageable lengths, or to strip the pipe and bonding medium off the wire rope whereby the latter can be used again.

Alternatively, the pulling action is by means of a winch preferably having a tapered drum with a fixed end plate and a removable end plate, the aforesaid integrated assembly being wound on the tapered drum and, at the end of the extraction operation, easily removed from the tapered drum by removal of the end plate so that the coiled integrated assembly can be simply slid off the tapered drum.

The wire rope is preferably of cored multi-strand configuration and preferably has an outside diameter as close to the internal diameter of the lead pipe as is possible commensurate with the provision of the annular gap for receiving the settable bonding medium.

The wire rope is preferably spun through the lead pipe against a counterflow of water which facilitates wire rope insertion while also preparing the lead pipe for receiving the settable resin.

Air may be blown through the annular gap prior to insertion of the settable bonding medium to remove debris therefrom.

The term "wire rope" used herein and in the claims includes any flexible element which is structurally and/or functionally equivalent to wire rope per se, chain for example.

The settable bonding medium is preferably a cementitious material but may, inter alia, be an expanding two part fast cure polymer material (resin and hardener).

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which :-

Fig. 1 is a diagrammatic view of a typical water distribution system;

Fig. 2 is a diagrammatic view of stage I of the pipe extraction and replacement method of the present invention;

Figs. 3 and 4 are respectively a perspective view and a detail view of a spinner machine employed in the present invention.

Fig. 5 is a perspective view of a water supply arrangement as employed in the present invention;

Fig. 6 is a diagrammatic view of stage II;

Fig. 7 is a sectional view of a bonding medium insertion arrangement for use in the present invention;

Fig. 8 is a sectional view of an alternative bonding medium insertion arrangement;

Fig. 9 is a sectional view of the integrated assembly of lead pipe, wire rope and binding resin or grout;

Fig. 10 is a diagrammatic view of stage HE; Fig. 11 is a diagrammatic view of stage IV; and Figs. 12 and 13 are diagrammatic views of an alternative stage IV. Referring to Fig. 1, the water distribution system comprises a main water supply pipe or conduit 20 extending underground along a street closer to one side than the other with underground lateral lead pipes 21 extending laterally therefrom to house inflow pipes 22 via control cocks 23.

An object of the present invention is to remove these lateral lead pipes 21 and replace them with plastic pipes.

Viewing Fig. 1 the right hand lead pipes 21 due to their relatively short lengths may be replaced by the aforementioned "trenching" method but may, if required or desired, be replaced by the method according to the present invention used to replace the left hand lead pipes 21.

According to the method of the present invention the main water supply pipe or conduit 20 is exposed by excavation as indicated at 24 and similarly the control cock region of the left hand lead pipe 21 is exposed by excavation 25.

The lead pipe 21 is severed from the main supply conduit 20 (length X for example) and from the control cock 23 (length Y for example) and (see Fig. 2) a water supply 26 is connected to the severed end of the lead pipe 21 at the control cock end to provide a small flow of water along the lead pipe 21 towards the excavation 24.

A wire rope 27 of cored helical multi-strand configuration as shown is fed from a coiled supply 28 by a power driven, preferably air powered, spinner machine 29 into and through the lead pipe 21 from excavation 24 to excavation 25 until the length of wire rope 27 projects beyond the severed end of the lead pipe 21 in the excavation 25. The wire rope 27 is severed at the spinner machine 29 end with a length thereof also exposed outside the lead pipe 21.

More specifically (Figs. 3 and 4), the spinner machine 29 comprises a basket drum 30 containing the wire rope 27 is rotated by an air motor 31 about a central axis. The wire rope 27 passes from the central area of the basket drum 30 into and through a swan neck pipe 32 emerging therefrom at the central axis at the front of the spinner machine 29 where it passes through an assembly of three rollers 33A, 33B and 33C whereof their axis are parallel to the axis of the wire rope 27, the rollers being spaced 120° apart from each other. These rollers 33A, 33B and 33C are loaded by spring loading units as indicated at 34 into contact with the rotating wire rope 27 (see arrow A), spring tension being adjustable as indicated by adjustment levers 35.

The rollers 33A, 33B and 33C can be angled synchronously about the rotating wire rope 27 and, due to being pressured against the latter, drive the rotating wire rope 27 forwardly.

By selecting the angling of the rollers 33A, 33B and 33C the rotating wire rope 27 can be driven forwards (see arrow B) or in reverse. The more acute the angling the greater the linear speed of the rotating wire rope 27.

The spinner machine 29 has a support frame 36. The above-described spinner machine 29 is of known construction to those skilled in the art of wire rope handling and no claim is made to same per se.

Any other convenient mechanism for driving the wire rope 27 through the pipe 21 with or without spinning of the wire rope 27 (such spinning being optional) may be employed in the present invention.

The outside diameter of the wire rope 27 is as large as is possible commensurate with its spinning passage along the lead pipe 21 and the provision of an annular gap or space 37 between the wire rope 27 and the inner wall surface of the lead pipe 21.

The back-flushing (water supply) arrangement 26 (see Fig. 5) is a dual purpose unit which is fitted on to the pipe 21 at the severed end in excavation 25.

A tool 38 with a pointed end 39 is hammered into the end of the pipe 27 to splay the end (see 27A), the end of the pipe 27 being enclosed in a sleeve 40.

The splayed end 27A is then trapped between a centrally-bored, quick-fit connector 41 and the sleeve 40, the splayed end 27A sealing on the conical end 42 of the connector 41 which is screw-threaded to the sleeve 40 at 43.

A water supply pipe 44 is connected to the connector 41 to feed water along the pipe 21 and the annular gap 37 formed as the rotating wire rope 27 is driven along the pipe 21.

The flow of water along the lead pipe 21 during the spinning input of the wire rope 27 not only assists passage of the wire rope 27 along the lead pipe 21 but also serves to prepare the inner surface of the lead pipe 21 for the next stage of the method according to the present invention which is the insertion of a settable resin or grout into the annular space or gap 37 between the wire rope 27 and the lead pipe 21. However, before insertion of the settable resin or grout, the water supply pipe 44 may be disconnected and an air hose fitted to blow compressed air along the annular gap 37 to remove any debris contained therein.

The compressed air will also blow out any flushing water contained or remaining within the annular gap 37.

The settable bonding material employed may either be a cementitious material, i.e. a grout, or a settable resinous material.

The settable resin employed may be an expanding two-part fast cure polymer material comprising a resin and a hardener which, for example, is delivered in known manner in precise predetermined volumes in what is known as a "pail". The resin and hardener are contained within their individual receptacles, the hardener and resin being brought together prior to use and vigorously mixed either manually or by power means for example an air driven paddle arrangement.

The "pail" is indicated at 44 in Fig. 6. It is open topped and a delivery pipe 45 extends therefrom to the annular gap 37 between the wire rope 27 and the lead pipe 21.

The pail 44 is contained within a pressure pot 46 into which is connected an air compressor 47 by a pipe 48.

When the compressor 34 is operated it causes the resin/hardener mix, (hereinafter simply called "resin") to flow along the pipe 45 and to be pumped along the annular gap 37 until there is a mass of resin 49 (Fig. 8) extending along the length of the lead pipe 21 filling the annular gap 37 between the latter and the internal wire rope 27.

When it can be seen that there is outflow of resin 49 at the control cock end of the lead pipe 21 pumping of the resin is ceased and the grout is allowed to set or cure.

The resin 49 is delivered (see Fig. 7) into a sleeve 51 surrounding the lead pipe 21 and the inserted wire rope 27 (no longer spinning), a seal 52 being fitted between the sleeve 51 and the wire rope 27 and a seal 53 being fitted between the sleeve 51 and the lead pipe 27.

In an alternative bonding medium insertion arrangement (see Fig. 8) the lead pipe 21 is fitted with a sleeve 40A and connector 41A similar to those illustrated in Fig. 5 and grout 49A is delivered through the connector 41A by a syringe or reciprocating pump 50 into the annular gap 37 between the lead pipe 21 and the wire rope 27.

The resin or grout 38 is formulated to provide a bonding medium of just the correct viscosity to allow free flow into and along the annular gap 37 but not too thin so as to tend to simply run away.

The water/compressed air delivery system (see Fig. 5) and the bonding resin delivery system (see Figs. 6 and 7 or Fig. 8) being disconnected the grout 38 is allowed to cure or set.

After completion of the setting or curing the lead pipe 21, internal wire rope 27 and intervening binding grout 49 filling annular space 37 (see Fig 9) forms an integrated mass. The integration will be assisted by the configuration of the wire rope 27 and also the irregularities in the internal surface of the lead pipe 21 which result from long usage of the latter or the passage of the wire rope 27 therealong.

If required the lead pipe 21 integrated with the wire rope 27 by the binding grout 49 can simply be extracted by the means such as is described hereinafter for example with reference to Fig. 10 or Figs. 11 and 12.

However, the primary purpose of this invention is to replace the extracted lead pipe by fresh pipe preferably plastic pipe as is described hereinafter with reference to Figs. 10 and 11 or Figs. 10, 12 and 13.

The next stage of the pipe replacement method according to the present invention is illustrated in Fig. 10 and in this Figure the lead pipe 21 is viewed at the control cock end i.e. the end in excavation 25.

There is shown in Fig. 10 a replacement plastic pipe 54 which will be fed off a coil or reel (not shown).

Referring to Fig. 10 there is shown a lead pipe/plastic pipe jointing member 55 having a male spigot 56 over which the plastic pipe 54 fits. An external clamping collar 57 is secured around the plastic pipe 54 and spigot 56.

The jointing member 55 is then spiggoted into the end of the integrated lead pipe/wire rope/grout assembly 27,21,49 as indicated at 56A and connection is effected by a clamping ring 58.

The jointing member 55 is tapered, as shown to facilitate its passage along the lead pipe path and to increase the size of the hole within which the lead pipe lies to facilitate passage of the plastic pipe 54 therethrough.

Reference is now made to Fig. 11 of the drawings and there is shown excavation 24 within which is disposed a mounting frame 59 which mounts a hollow fluid operated pulling ram 60 which grips the exposed end of the integrated assembly 21, 49, 27 by means of a collet clamp 61 for example and serves to pull the integrated assembly out of the earth strata into the excavation 24. The hollow ram bore is large enough to accommodate any sweated joints in the lead pipe 21. Downstream of the pulling ram 60 is a hydraulic chopper or cutting device 62 or a device for stripping the lead pipe 27 and grout 49 from the wire rope 27.

If an ordinary ram is used for pulling the clamp may be, for example, a V-notch clamp.

Operation of the pulling ram 60 pulls the integrated assembly 21, 49, 27 into the excavation 24, the integrated assembly passing through the hollow pulling ram 60 where it is chopped into convenient, manageable lengths by the chopper or cutting device 62 or stripped for removal and disposal. When the end of the plastic pipe 54 is exposed in excavation 24 the chopping or cutting device 62 is rendered inoperative and the plastic pipe 54 is connected to the main water supply conduit or pipe 20.

The plastic pipe 54 is, at its other end, cut off its supply reel (not shown) and connected to the control cock 23. Alternatively, a predetermined discrete length of plastic pipe 54 may have been provided for insertion.

An alternative pulling arrangement is shown in Figs. 12 and 13. Here again there is a mounting frame 63 disposed in excavation 24 which mounting frame supports a winch 64 driven by a convenient motor 44.

The winch 64 preferably has a tapered drum 65 with a fixed end plate 66 and a removable end plate 67 the drum tapering towards the removable end plate 67 and being notched as indicated at 68 at its smallest diameter end.

A free end of the wire rope 27 of the integrated assembly is engaged in the notch 68 and the plate 67 is releasably secured in position on the drum 65. The winch 64 is then driven to coil the integrated assembly 21, 49, 27 onto the drum 65 until once again the plastic pipe 54 is exposed in excavation 24. Thereafter the plastic pipe 54 is connected at opposite ends to the main supply pipe or conduit 20 and the control cock 23.

The end plate 67 is removed from the winch drum 65 and the coiled integrated assembly can easily be slid off the drum 65 for removal and disposal.

It is to be noted that during the grouting process the delivery pipe 50 may be connected to the annular gap 37 via a blow-down/grouting collar which is preferably disposable in nature.

It is further to be noted that the water supply installation may not, in fact, be provided with the control cocks 23, the new plastic piping 54 being appropriately connected to the inflow pipes 22.

Claims

1. A method of extracting an underground pipe from earth strata, the method comprising the steps of threading an elongate support or carrier through the length of an underground pipe leaving an annular gap therebetween, filling the annular gap with a settable fluent bonding medium, and permitting the latter to set or cure to bind the pipe and the elongate support or carrier together to form an integrated assembly for removal from underground by pulling and/or pushing.

2. A method as claimed in claim 1 comprising the preliminary step of exposing two spaced ends of the pipe, preferably by excavation, and, if necessary, severing said ends from service or other underground installations.

3. A method as claimed in claim 2 comprising the step of driving a wire rope constituting the elongate support or carrier through the underground pipe from one exposed end to another until the wire rope projects from the other pipe end.

4. A method as claimed in claim 3 comprising the step of spinning the wire rope during its movement through the underground pipe.

5. A method as claimed in claim 3 or 4 comprising the step of providing a counterflow of water through the underground pipe during wire rope insertion for lubrication and/or cleaning purposes.

6. A method as claimed in any one of claims 3 to 5 comprising the step, subsequent to wire rope insertion, of blowing air along the annular gap between the pipe and the inserted wire rope to remove debris and/or water.

7. A method as claimed in any one of claims 3 to 6 comprising the steps of introducing the settable fluent bonding medium into the einnular gap between the pipe and the inserted wire rope and allowing same to set or cure to integrate the wire rope with the pipe.

8. A method as claimed in claim 7 in which the settable fluent bonding medium is pumped into the annular gap to fill the length thereof in the pipe to be removed.

9. A method as claimed in any one of claims 3 to 8 comprising the step of pulling the integrated pipe/wire rope/bonding medium out of the earth strata.

10. A method as claimed in any one of claims 7 to 9 used for underground pipe replacement comprising the steps of coupling a fresh pipe to the trailing end of the underground pipe to be extracted, and pulling it same into the hole or passage left by the latter.

11. A method as claimed in claim 10, comprising the step of upsizing the hole occupied by the underground pipe as it is withdrawn to facilitate entry of the fresh pipe.

12. A method as claimed in claim 10 or 11, comprising the step, if necessary, of coupling the ends of the inserted fresh pipe to underground services or other installations.

13. Apparatus for carrying out the method claimed in any one of claims 1 to 12, comprising, inter alia, means for driving a wire ripe, with or without a spinning action, along an underground pipe.

14. Apparatus as claimed in claim 13 comprising a water pumping arrangement for coupling to one end of the underground pipe to provide a water flow counter to the wire rope being inserted.

15. Apparatus as claimed in claim 14 comprising a pressurised air blowing arrangement for coupling to said one end of the underground pipe to blow debris and/or water through the annular gap between the pipe and the inserted wire rope.

16. Apparatus as claimed in any one of claims 13 to 15 comprising means for pumping or otherwise introducing a settable bonding medium into the annular gap between the pipe and the inserted wire rope to integrate them for removal by pulling.

17. Apparatus as claimed in claim 16, comprising pulling means constituted by a hollow or other fluid-operated ram with which is preferably associated a chopping device to cut the extracted integrated assembly into pieces of manageable lengths, or to strip the pipe and bonding medium off the wire rope whereby the latter can be used again.

18. Apparatus as claimed in claim 16, comprising pulling means constituted by a winch preferably having a tapered drum with a fixed end plate and a removable end plate, the aforesaid integrated assembly being wound on the tapered drum and, at the end of the extraction operation, easily removed from the tapered drum by removal of the end plate so that the coiled integrated assembly can be simply slid off the tapered drum.

19. Apparatus as claimed in any one of claims 16 to 18 comprising a tapered coupling member for connecting a fresh pipe to the trailing end of the integrated underground pipe with its inserted and bonded wire rope, the tapered coupling member serving to upsize the hole to facilitate entry of the fresh pipe.