PIPE CONNECTING METHOD

Abstract: A method for sealing the gap between a sewer liner (3) and a connecting conduit (2) to the sewer, such as a drain, includes providing a hole in the liner for communication with the conduit, sealing a flexible bag (7) to the liner about said hole, and applying pressure to the bag to force at least a portion of the bag into the conduit so as to bridge the gap between the liner and the sewer at the point of connection of the conduit. Preferably a suitable grouting material is then introduced into the gap so as to surround the bag where it bridges the gap, thereby making a permanent seal between the liner and the connecting conduit.

Description: • PIPE CONNECTING METHOD This invention relates to methods for connecting together pipes, and especially to methods for connecting existing drains to sewers which have been renovated by slip lining with plastic pipe. A method of lining sewers with short lengths of plastic pipe with a "snap on" clip fastening arrangement machined in the ends of the pipe is known. In this method the sewer is first surveyed and the approximate position of live drains, steps and protruding laterals are noted. The pipe lengths used are planned to allow for access to the sewer through the manhole as a maximum length, and this length is varied to prevent a drain entry in ' the area of a pipe joint. The pipe ends ' are prepared to form a snap closure and are fitted with an induction ring. Two small diameter pieces of pipe are fused to either end of the liner pipe and these are used to maintain radial alignment of the pipe during insertion by threading through a wire or cable that is positioned along the sewer. The sewer is cleaned, protruding laterals removed, and "proved" by drawing through the ^ sewer a length of liner pipe. Communication is set up between the two manholes at either end of the section to be lined. The first and subsequent sections are OMPI drawn through, snapped together and fused with the internal induction ring connected to an R.F. generator until the pipe length that requires drain access is reached. A closed circuit television camera is then drawn through, contained within a "cage", the outer ribs of which are graduated. This cage is butted to the last piece of liner pipe inserted, and the camera scanned until the drain connection is located- The diameter, longitudinal and radial position of this drain, relative to the last pipe liner pipe is made by reference to the graduated ribs of the cage. The measurements are transposed to the next length of liner and a hole is cut, appropriate to the size of the drain. This next length of liner is then inserted and positioned in the same way ' as preceding lengths. In order to seal the gap between the liner and the original sewer, where the existing drain joins the sewer, a flexible bag is introduced into the hole made in the l-iner for coiπmunication with"the existing drain, said bag being sealed to the liner about said hole and pressure being applied to said bag to force at least a portion of the body of the bag into the existing drain and so as to bridge the gap between the liner and the existing sewer at the point of entry of the existing- drain. Preferably material is introduced via the wall of the flexible bag into the space between the liner and the original sewer. The present invention also provides apparatus for sealing the gap between the liner and the existing sewer, at the point of entry of an existing drain into the sewer, said apparatus including means for locating about the hole in the liner, communicating with the existing drain, a flexible bag, attachable to or attached to said means such that pressure applied to the body of the bag will force the body of the bag into said existing drain so as to seal the gap between the liner and the existing sewer. An embodiment of the present invention will now be described, by way of example only, and with reference to the accompanying drawings, in whic :- Figure 1 illustrates a method and apparatus in accordance with the present invention; and Figure 2 illustrates the same method and apparatus as Figure 1 but at a later stage in the operation of the method. Referring to the drawing, an existing sewer 1 is connected to an existing drain 2. Located within sewer 1 is a polyethylene liner 3 having a hole 3a_ therein allowing communication between the interior of sewer 1 and drain 2. A plastics ring 5 is fused into hole 3a making use of an induction ring 4 which is heated up by an induction generator (not shown) . Clipped to ring 5 by means of sleeve 6 is a bag 7 made of flexible, air tight material. The neck ' ^of the bag is formed into an "0" ring 7a_ which locates into a groove formed in the wall of retaining sleeve 6. At the closed end of bag 7 is an extraction cord 8 which is fed through to the manhole. With the device in the position shown in Figure 1 air pressure is applied to the sealed section which causes the bag 7 to inflate up into drain 2, sealing drain 2 and forming a shuttering within the annulus between the liner 3 and the original sewer 1. Attached to the wall of bag 7 is a pipe 9 , which extends through wall 7 and allows grouting material to be fed along the pipe into the above-mentioned annulus. During the inflation of the bag 7 cord 8 is drawn up into the drain and the distance of movement of the remote end of the cord is used to indicate that the bag is correctly inflated. The force acting on the bag, in a direction into drain 2, tightens the bond between sleeve 7 and ring 5, thus ensuring the retention of the bag in position. The bag may be reinforced or stiffened in the area where it forms its shuttering role. Once the grouting medium has set the pressure may be released, and the bag 7 and retaining sleeve 6 removed by pulling on the cord. In an alternative embodiment the entire length of sewer may be sealed, all the drain connections inflated and the entire length of lining grouted. In a further alternative embodiment the grouting material, instead of being fed through the wall of the bag via pipe 9 is instead fed by a suitable conduit to the gap via ring 5 or sleeve 6. The grouting material may be any suitable material such as a foamable polyurethane material. Such a material can be injected into the gap where it may expand to many times its original volume so as effectively to seal the gap where the drain connects to the sewer.

Claims: - o - CLAIMS : 1. -A method of sealing the gap between a sewer liner and a connecting conduit to the sewer characterised in that the method comprises providing a hole in the liner for communication with the conduit, sealing a flexible bag to the liner about said hole and applying pressure to said bag to force at least a portion of the bag into the conduit so as to bridge the gap between the liner and the sewer at the point of connection of the conduit. 2. A method according to claim 1 characterised in that the mouth of the bag is attached to or formed within a relatively rigid ring which in turn is attached to the liner about said hole. 3. A method according to claim 2 characterised in that the ring includes a first annular portion which is fused to the liner and a second annular portion, to which the bag is attached, said second portion being disengagably attached to said first portion. 4. A method according to claim 2 or claim 3 characterised in that the grouting material is introduced into the gap between the liner and the sewer and so as to surround the bag where it bridges this gap. 5. A method according to claim 4 characterised in that the grouting material is introduced via the wall of the flexible bag. 6. A method according to claim 3 or claim 4 characterised in that the grouting material is introduced via said ring. 7. A method according to any of claims 4 to 6 characterised in that after the grouting material has been introduced the bag is removed by means of a cord attached to the bag. - 5 - 8. Apparatus for sealing the gap between a sewer liner and a connecting conduit to the sewer characterised in that the apparatus comprises means for locating about a hole in the liner, said hole being for communication with the conduit, a flexible bag, attachable to or attached to said means such that pressure applied to the body of the bag will force the body of the bag into the conduit so as to bridge said gap.

Inventors: RICE NIGEL LEONARD
Applicants: HAXEY ENG LTD, RICE NIGEL LEONARD
Application year: 1982
Main classification: E03F3
IPC codes: E03F3, F16L55