GB2291690A

GB2291690A - Device for replacing lead piping

Info

Publication number: GB2291690A
Application number: GB9515326A
Authority: GB
Inventors: Philippe Javelle
Original assignee: Eau et Force SA
Current assignee: Eau et Force SA
Priority date: 1994-07-26
Filing date: 1995-07-26
Publication date: 1996-01-31
Anticipated expiration: 2015-07-26
Also published as: FR2723780A1; GB2291690B; FR2723780B1; GB9515326D0

Abstract

A device for replacing buried lead connection pipes, without digging ditches, the said device comprising a cutting tool and an expanding cone which also acts as a means for pulling replacement plastics piping. The device comprises a traction stand 5 on which there is mounted a device 6 actuating a double-drum reel 7 via a traction cable 8 wound on to the drum (7a) (Fig. 2) of larger diameter. The cutting tool 10 (Fig. 3) is positioned at one end of a cable 9 which is introduced into the buried lead piping 1 and is secured to the drum of smaller diameter. The rear portion (14) of the expanding cone 11, is reamed so as to accommodate a locking stop device (15) which locks the expanding cone (11) on the cable 9 introduced into the lead piping 1 and also pulls the replacement plastics piping 12. <IMAGE>

Description

DEVICE FOR REPLACING LEAD PIPING The invention relates to a device allowing replacement of lead piping. more particularly connection pipes, without the need to dig ditches.

Drinking-water distribution networks generally comprise cast iron or concrete piping arranged on one side of a road, with connection pipes crossing the road at regular intervals in order to supply water to the buildings on the other side of the road. Connection pipes of this type manufactured several decades ago were made from lead, the toxicity of which is known. When a main length of piping is being replaced because it is faulty, all the lead connection pipes are now systematically replaced with pipes made from plastics, generally polyethylene.

It is known that cast iron or concrete piping can be replaced without digging ditches to expose it, namely by "exploding" it with a fuse having a plastics pipe mounted at its rear, the new pipe allowing the same flow rate as the original pipe. This explosion process cannot be carried out on lead connection pipes.

Water companies or their sub-contractors currently use the following processes for extracting lead connection pipes: - a process using anchoring parts arranged along a cable introduced into the pipe, traction on the cable breaking the lead connection pipe; or alternatively - a process of pushing the lead connection pipe from one end, using a cone secured on a traction cable; or as a further alternative - a process of digging a ditch and extracting the lead connection pipe; this process requires considerable excavation work, disrupts traffic and necessitates road repairs.

The two first processes do not require excavation work but do need heavy and powerful equipment producing a traction force of between 4000 and 7000 daN, the equipment therefore being costly. The device of the invention allows this problem to be solved.

To this end, the subject of the invention is a device for replacing buried lead connection pipes, without digging ditches, the said device comprising a cutting tool and an expanding cone also acting as a means for pulling replacement plastics piping. characterised in that the device comprises a traction stand on which there is mounted a device actuating a doubledrum reel via a traction cable wound on to the drum of larger diameter, and the cutting tool is positioned at one end of a cable which is introduced into the buried lead piping and which is secured to the drum of smaller diameter, and the rear portion of the expanding cone is reamed so as to accommodate a locking stop device which locks the expanding cone on the cable introduced into the lead piping, and also pulls the replacement plastics piping.

In a first embodiment, the cutting tool and the expanding cone are formed as a single part.

In a second embodiment, the cutting tool and the expanding cone are two separate components, arranged at a certain distance apart on the traction cable.

The invention will now be described in greater detail with reference to the attached drawings.

Fig. 1 is a schematic sectional view of the process as it Is carried out; Fig. 2 is a front view of the traction stand which can be seen from the side in fig. 1; Fig. 3 is a detailed view of the first embodiment of the cutting tool and expanding means; Fig. 4 is a detailed view of the second embodiment of the cutting tool and expanding means.

Fig. 1 is a sectional diagram showing the operating principle of the process of the invention. A lead pipe 1 is buried in the ground 2. In the case of a connection pipe, the ground 2 is a road which is traversed at right angles by the connection pipe 1. To replace the pipe 1, extraction excavation 3 takes place at one end of the pipe, and introduction excavation 4 takes place at the other end in order to introduce the new piping. A traction stand 5 is installed in the excavated region 3, the said stand comprising a traction apparatus 6 and a double drum 7. A cable 8 connects the traction apparatus 6 to the double drum 7.

A cable 9 is passed into the pipe 1 at its end exposed by the excavated region 4, that end of the said cable which emerges into the excavated region 3 being secured to the double drum 7. A cutting tool 10 is then mounted on the other end of the cable 9, in addition to an expanding cone 11 also acting as a means for pulling the replacement piping 12.

Structural details of the traction stand 5, the cutting tool 10, the expanding means 11 and the fitting of the piping 12 will subsequently be explained as an example.

The cutting tool 10 is introduced into the lead pipe and is brought into contact therewith. The traction apparatus is subsequently actuated, thus winding the cable 9 on to the double drum 7 and causing the cutting tool to advance inside the piping 1.

Whilst the traction force leaves the lead piping 1 in place, the expanding means 11 separates the cut edges in order to allow introduction of the replacement pipe 12 inside the original pipe 1, the new pipe having substantially the same inner diameters as the original pipe in order to allow the same flow rate.

If the lead pipe adheres relatively loosely to the surrounding ground (for example if the ground is sandy or damp, etc.) the traction force may then be sufficient for the expanding means 11 to push the lead piping along in front, the piping then winding on to the double drum 7. The piping 1 is then fully extracted and the piping 12 replaces it.

Fig. 2 is a front view of the traction stand 5. The stand comprises, for example, a rectangular frame 20 mounted on feet 21, thus allowing easy positioning on excavated regions which may contain other piping in addition to that for replacement (electric cables, gas mains etc.). A traction apparatus 6 is mounted on the frame 20. For example, this could be a hydraulically driven '?IRFOR" machine, allowing production of a traction force of up to 1600 daN whilst still being compact and of low cost.

The traction apparatus 6 is connected via a cable 8 to a double drum 7 which is also mounted on the frame 20. A double drum of this type is preferred so as to reduce the traction force applied to the cable 9.

Generally, the cable 8 will be wound on to the drum 7a of larger diameter and the traction cable 9 will be wound on to the drum 7b of smaller diameter. The diameter of the drum 7a is, for example, twice that of the drum 7b. In a case where the lead piping is extracted, it is also possible when using a double drum of this type to wind the piping on to the drum 7b, without disrupting unwinding of the cable 8 on the drum 7a.

Fig. 3 is a sectional view showing a first embodiment of a cutting tool and an expanding means. The cutting tool 10 is a cylindrical tube with an outer diameter slightly less than the inner diameter of the lead piping 1, a cutter 13 being mounted on the cylindrical tube. The diameter of the cylindrical tube 10 widens behind the cutter 13 in order to form the expanding cone 11 which is extended by a second cylindrical tube 14. A locking stop device 15 is threaded on to the cable 9 and positioned at the interior of the cylindrical portion 14. The said locking stop device is, for example, a tube 15 having at its front part (relative to the direction of traction exerted on the cable 9) members for securing on to the cable 9, for example three pressure screws 16 arranged at 120Q apart.The rear portion of the locking stop device 15 has an outer threaded portion 17 allowing it to be screwed directly into the plastics piping 12.

In accordance with the second embodiment shown in fig. 4, the cutting tool and the expanding cone are spaced by a certain distance, thus allowing expanding of the lead piping in two stages. The cylindrical tube 10a on which the cutter 13 is mounted also comprises a relatively short truncated conical portion, extended by a cylindrical portion 14a of an outer diameter which is less than that of the cylindrical portion 14 of the expanding means in fig. 3. A locking stop device 15a, similar to the front part of the locking stop device 15, allows the cutting tool to be secured on to the cable 9. A short cylindrical tube 10b is extended behind the cutting tool by the expanding cone 1 lea which is itself extended by a cylindrical tube 14b. The locking stop device used to secure the expanding cone on the cable 9 and to pull the new piping 12 is entirely similar to that used in the embodiment in fig. 3.

Claims

1. A device for replacing buried lead connection pipes. without digging ditches, the said device comprising a cutting tool and an expanding cone which also acts as a means for pulling replacement plastics piping, the device comprising a traction stand on which there is mounted a device actuating a double-drum reel via a traction cable wound on to the drum of larger diameter, and the cutting tool is positioned at one end of a cable which is introduced into the buried lead piping and which is secured to the drum of smaller diameter, and the rear portion of the expanding cone is reamed so as to accommodate a locking stop device which locks the expanding cone on the cable introduced into the lead piping and also pulls the replacement plastics piping.

2. A device according to claim 1, wherein the cutting tool and the expanding cone are formed as a single part.

3. A device according to claim 1, wherein the cutting tod and the expanding cone are two separate components, arranged at a certain distance apart on the traction cable.

4. A device for replacing buried lead connection pipes, the device being substantially as hereinbefore described with reference to any of the accompanying drawings.