CONSTRUCTION METHOD OF REVERSAL TUBE LINING ON CONDUIT WITHOUT EXCAVATION

Abstract: A construction method in which a conduit for gas or water supply buried in the ground is internally lined (internal lining) with a tube advanced within the conduit while being reversed by means of fluid pressure. The whole of lining operation is performed at a part of the conduit appearing on the ground. First, a distance from the entrance of the conduit to the service tee through the conduit is measured and a tube for lining is reversed after cut to a length slightly longer than the length thus measured. As a result, a non-reversed part of the tube in short length is left in the conduit on the side of the forward end of the tube. The non-reversed part can be utilized when an unwinding tape tied to the tube is cut by a cutter inserted into the conduit. After reversing the lining tube, a warming tube is similarly reversed and warm water hose for internal circulation of warm water is inserted into the warming tube so that the conduit is internally lined with said lining tube over which thermosetting adhesive has been spread. After completion of internal lining, the warm water hose is pulled out, the warming tube is then pulled out with the unwinding tape pulled, and the unwinding tape of the lining tube is cut to be recovered. As the last step, a fusing head is inserted into the conduit for melt-opening the tip of the lining tube for fluid passage and the fusing head is pulled out, thereby lining operation being completed.

Description: This invention relates to the repair of underground pipelines using a method whereby a lining tube is inserted into a pipe and thereafter reversed using fluid pressure whereby the liner closely adheres to the internal surface of the pipe. This invention is thus applicable to gas or water pipelines which are buried underground and enables such pipes to be lined from a single location without digging up the pipeline which is to be repaired. A prior art method of lining pipes is described in conjunction with Figure 8 of the accompanying drawings wherein an excavation 02 is made to expose the branch section of a main pipeline 01 to gain access to the service tee 03. A branch pipeline 09 is attached to the service tee 03 and through this branch line a lining tube 010 is fed using a machine 08 which is attached to the riser pipe 06 above the ground level. The end of the lining tube 010 is closed and once the tube has reached the service tee 03 the end is cut and installed on to the tee by means of a machine 05. A heating means 011 is connected to the machine 05 and to the riser pipe 06 and this machine circulates hot water in the direction shown by the arrows into the lining tube 010 so as to harden the thermosetting adhesive agent which is provided around the lining tube so as to secure the tube to the internal surface of the pipe 09. This prior art method requires an excavation 02 to be made to expose the main pipe 01 resulting in labour and expense and the necessity to back fill and make good the surface. There is also the problem of traffic disruption where the main pipe is in a street. In Japanese patent application JP-A-63 286326 there is disclosed an arrangement for lining a branch pipe wherein a liner bag or tube (1) is formed by a tubular liner (3) coated with a resin material (2), the liner bag comprising the liner (3) which is impregnated with the thermosetting resin film (2). This assembly is then passed through the guide pipe (8) into which hot water is poured through the hose (10). The end part (1a) of the water is poured through the hose (10). The end part (1a) of the liner (1) is extended past the pipe opening (11) and is caused to distend the elastic cap (6) connected with the end part (1a) of the liner bag. After completion of the operation, the elastic cap (6) is removed together with the hot water hose (5). By contrast, the present invention uses a second lining tube with the water pipe being inserted into this tube. In this operation the advantage is that hot water does not come into contact with the adhesive coated or impregnated tube which forms the actual liner after installation. In this invention the method of lining a pipe does not require excavation where the pipe joins the main pipeline (Japanese Application 147549 - 1988). According to this invention there is provided a method for lining an underground pipeline, wherein a lining tube is inserted into the end of the pipeline by a reversing operation whereby the tube is turned inside out as it progresses into the interior of the pipeline with the surface of the tube adjacent the internal surface of the pipeline being coated with a thermosetting adhesive material, the remote end of the adhesive coated lining tube being closed off, hot water being passed through the interior of the lining tube to set the adhesive material to bond the lining tube to the pipeline, characterised by: a) a second lining tube being inserted into the lining tube the remote end of said tube being closed off, b) a water pipe being inserted into the second lining tube up to the remote end, c) hot water being passed into the second lining tube and withdrawn through the water pipe, the hot water serving to cure the thermosetting adhesive, d) the water pipe and second lining tube being withdrawn, e) the remote end of the lining tube being cut open. Preferably the closed remote end of the lining tube is connected with a draw-line to enable the tube end to be positioned accurately and retained. Advantageously, the method is applied for lining a branch pipe connected to a main pipe through a service tee by operating through the riser pipe portion of the pipe, characterised in that the distance to the service tee is measured by a probe, the lining tube being inserted into the pipe by a pushing rod up to the service tee with the closed off end of the lining tube drawn back and retained by a draw-line in such position. The invention is further described and illustrated with reference to the accompanying drawings showing an example of the method according to this invention. Referring to the drawings: Figure 1 shows diagrammatically the method of measuring the pipeline to be lined using a measuring coil, Figure 2 shows the pipeline with the lining tube reversed therein, Figure 3 shows the pipeline with lining tube and with a reversed pipeline forming the heating tube, Figure 4 shows the pipeline with a hot water hose inserted therein and the full length of the heating tube, Figure 5 shows the rewinding tape being severed using a fusion cutter, Figure 6 shows the remote end of the lining tube being fusion cut with the cutter, Figure 7 shows the pipeline with the completed lining tube in position, and Figure 8 shows schematically the prior art arrangement previously described. The embodiment shown in the drawings relates to the lining of a supply pipe 4 which is connected to a service tee 2 provided on a main pipeline 1. The supply pipe 4 connects with a riser pipe 3 which, as is known, couples with a suitable supply metering device (not shown). As a first step the length of the pipe 4 up to the service tee 2 is measured by using a machine 5 coupled to the riser pipe 3. This machine is adapted to supply information on the kind and quantity of the surface and couplings along the length of the pipe in addition to the distance. For this purpose a sensor 6 is attached to the end of a measuring coil 7 which is extended from a suitable apparatus 5. Couplings and the like along the length of the pipe may be detected, for example using sound, and the feed of the coil 7 is stopped when the sensor 6 detects the service tee 2. The length of the pipe 4 can thus be measured from the length of coil 7 which has been inserted. In the next step, as shown in Figure 2, a lining tube 9 which is coated with a thermosetting adhesive material is reverse entered from the riser pipe 3 using a suitable reversing machine 8. A lining tube rewinding tape 10 is attached to the lining tube 9 and the length of the lining tube inserted is made slightly longer than the distance to the tee 2. The lining tube 9 is inserted whilst being turned inside out or reversed using the machine 8 and by means of an introduction machine 11 which pushes the tube along the pipe by means of an introduction rod 12. The rod 12 pushes the tube by means of the tip 13 which serves as a directional guide and assists in the smooth advance of the lining tube within the pipe. The action terminates when the rod reaches the inside of the service tee 2. In the next step, as shown in Figure 3, a heating tube 14 is fed into the lining tube 9 by a similar method of reversing or turning the tube inside out. The heating tube 14 has no adhesive but does include a pulling-back tape 10'. The next step, as shown in Figure 4, is to insert a hot water hose 15 into the heating tube 14 with the hose 15 connected to a hot water heating apparatus 16. Hot water is caused to flow through the heating tube 14 to the remote end and to flow back along the hose 15. The circulating hot water is at a temperature of about 70 o C. The hot water serves to harden the adhesive agent provided on the external surface of the lining tube 9 and as a result of this the tube 9 is intimately bonded to the whole internal surface of the pipe 4 from the tee 2 up to the riser pipe 3. A small part of the non-reversed section 9' of the lining tube 9 is left lying on the inside adjacent the service tee 2. In the next step the hot water hose 15 is withdrawn and the rewinding tape 10' is pulled in order to withdraw the heating tube 14 from within the pipe 4. Referring now to Figure 5, the rewinding tape 10 which is attached to the end of the lining tube 9 is passed through an annular electrically heated cutter 17 which is then passed down the tape 10 with the cutter connected to a cable rod 18 which is stopped at the non-reversed portion 9' of the liner tube. The cutter 17 is then energised and severs the rewinding tape 10 which may be extracted from the tube along with the rod and heater 17,18. Following this operation, and as shown in Figure 6, a further fusion cutting rod 20 with an electrical heater element at the tip is inserted until it abuts against the end of the lining tube 9 whereupon the cutter is energised to open up an aperture in the end of the lining tube 9. This then establishes communication between the service tee 2 and the branch pipe 4. The rod 20 is thereafter removed from the tube. Finally, Figure 7 shows the completed lining after the cutting operation has been completed. Because the whole of the operation can be effected from above ground and through the riser pipe the present invention provides advantages as follows. a) It is not necessary to excavate around the main pipe to expose the service tee, thus expense involved in digging and back filling and making good can be avoided. b) Because the lining tube is accurately extended to the location of the service tee, it will not pass into the main pipe and will therefore not cause an obstruction to the main pipe flow. Thus the main pipe is not obstructed should any maintenance work become necessary after the lining operation. c) It is a simple matter to accurately position the lining pipe using the measuring and sensing operation which speeds up the operation and improves efficiency. d) The cutting device comes into abutment with the unreversed section of the lining pipe and hence the position of the cutting can be accurately located.

Claims: Method for lining an underground pipeline (4), wherein a lining tube (9) is inserted into the end of the pipeline (4) by a reversing operation whereby the tube (9) is turned inside out as it progresses into the interior of the pipeline (4) with the surface of the tube adjacent the internal surface of the pipeline being coated with a thermosetting adhesive material, the remote end (9') of the adhesive coated lining tube (9) being closed off, hot water being passed through the interior of the lining tube (9) to set the adhesive material to bond the lining tube (9) to the pipeline (4), characterised by: a) a second lining tube (14) being inserted into the lining tube (9) the remote end of said tube being closed off, b) a water pipe (15) being inserted into the second lining tube (14) up to the remote end, c) hot water being passed into the second lining tube (14) and withdrawn through the water pipe (15), the hot water serving to cure the thermosetting adhesive, d) the water pipe (15) and second lining tube (14) being withdrawn, e) the remote end of the lining tube (9) being cut open. Method in accordance with Claim 1, characterised in that the closed remote end (9') of the lining tube (9) is connected with a draw-line (10) to enable the tube end to be positioned accurately and retained. Method in accordance with Claim 1 or 2, characterised in that the closed remote end of the lining tube (14) may be connected with a draw-line (10') to enable the tube to be withdrawn. Method in accordance with Claim 1, 2 or 3, characterised in that an electrically heated cutting device (19) is inserted into the lining tube (9) using a rod (20). Method in accordance with any preceding claim for lining a branch pipe (4) connected to a main pipe (1) through a service tee (2) by operating through the riser pipe portion (3) of the pipe (4), characterised in that the distance to the service tee (2) is measured by a probe (6,7) the lining tube (9) being inserted into the pipe (4) by a pushing rod (12) up to the service tee (2) with the closed off end (9') of the lining tube (9) drawn back and retained by a draw-line (10) in such position. Method in accordance with any preceding Claim 2 to 5, characterised in that a probe (12,13) is inserted into the adhesive coated lining tube (9) and/or the second lining tube (14) , the probe detecting the end of the pipe (3), the lining tube (9) and/or the second lining tube (14) being pulled back against the probe by means of a draw line (10,10') to accurately position the end (9'). Method in accordance with any preceding claims characterised in that the remote end (9') of the lining tube (9) remains unreversed and lies within the lining tube. Method in accordance with any preceding claim characterised in that the remote end of the second lining tube (14) remains unreversed and lies within the lining tube.

Inventors: IKEDA SEIICHI, IMAMURA MINORU, KOBAYASHI HIROAKI, TOYODA SHIGERU, IKEDA, SEIICHI, IMAMURA, MINORU, KOBAYASHI, HIROAKI, TOYODA, SHIGERU
Applicants: TOKYO GAS CO LTD, TOKYO GAS CO., LTD.
Application year: 1990
Main classification: B29C63
IPC codes: B29C63, F16L55, B29L23