IMPROVEMENTS RELATING TO THE LINING OF PIPELINES OR PASSAGEWAYS

Abstract: A method of lining a pipeline or passageway surface (10) wherein a first flexible tubular member (22) is everted into a pipeline or passageway surface to be lined, and to the trailing end of the first flexible tube is connected the folded thermoplastic lining pipe (30) so that it is pulled into the pipeline or passageway by virtue of the eversion operation, and wherein heated fluid is used for the eversion so that when the thermoplastic pipe is completely inside the pipeline or passageway, it will be surrounded by heated fluid to soften same, following which the softened thermoplastic pipe is inflated by fluid pressure onto the pipeline or passageway surface where it is allowed or caused to solidify in place.

Description: IMPROVEMENTS RELATING TO THE LINING OF PIPELINES OR PASSAGEWAYS This invention relates to the lining of pipelines or *^ passageways, for the rehabilitation, repair or restoration of same. 5 Mainly, the pipelines or passageways to be lined will be underground pipelines or passageways such as sewers, but the invention can be applied to above ground installations. 10 The lining of pipelines and passageways is well established technology, and a most popular and successful method of lining a pipeline or passageway comprises the insertion into the pipeline or passageway of a tubular member which when inserted into the 15 pipeline or passageway is of smaller overall dimension than the pipeline or passageway, and then is inflated or expanded onto the pipeline or passageway surface. The tubular member has the characteristic that when it is held in position on the pipeline or passageway surface, 20 it can be caused to harden or solidify into a rigid pipe, and so there is formed a "pipe within a pipe" and the formed rigid lining pipe remains by its own stiffness, in place in a lining position. 25 In one method, the lining pipe is flexible and includes or comprises a resin absorbent material such as a felt, which is soaked in curable resin and the resulting impregnated flexible pipe is moved into the passageway either by pulling or by eversion, and fluid pressure is 30 used to hold the still flexible lining pipe against the pipeline or passageway surface, unti the resin cures, where upon the pressure can be removed, leaving the rigid cured lining in place. In another method, a tubular member of a thermo-plastic material is folded in order to reduce its overall dimensions, and it is introduced into the pipe and when in the pipe it is heated in order to soften same so that by fluid pressure, it can be inflated onto the pipeline or passageway surface, following of which it is again cooled so that it will solidify and remain in place as the rigid plastic lining pipe. The present invention is concerned with the placement of thermo-plastic lining pipes on pipeline or passageway surfaces, and seeks to provide an effective and. convenient means for the insertion of the thermo-plastic pipe in its folded state into the pipeline or passageway surface. In accordance with the present invention, a first flexible tubular member is everted into a pipeline or passageway surface to be lined, and to the trailing end of the first flexible tube is connected the folded thermo-plastic lining pipe, so that it is pulled into the pipeline or passageway by virtue of the eversion operation, and wherein heated fluid is used for the eversion so that when the thermo-plastic pipe is completely inside the pipeline or passageway, it will be surrounded by heated fluid to soften same, following which the softened thermo-plastic pipe is inflated by fluid pressure onto the pipeline or passageway surface where it is allowed or caused to solidify in place. The first lining tube will preferably be of a material such as a fibre reinforced plastics material which is of sufficient tensile strength in order to effect the pulling into the pipeline or passageway of the thermo- plastic tube, and also will be of sufficient heat resistance to withstand the temperature of the hot fluid which performs the eversion. The -hot fluid preferably is water. The heated thermo-plastic pipe may be inflated by any suitable means such as by pressurising the interior of the soft heated pipe, or by everting a second plastic tube into the inside of the plastic pipe. The plastic pipe preferably is of p.v.c. or a polyolefin material. The former is preferred, because it softens and is handleable over a wider temperature range than the polyolefin. Also, it does retain tensile strength when heated enabling it satisfactorily to be expanded up on to the pipeline or passageway wall. An embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, wherein;- Fig. 1 is a sectional elevation showing an underground pipeline or passageway to be lined and the lining process according to an embodiment of the invention in commencement; Figs. 2 to 5 show similarly to Fig. 1 the various stages in the process. Referring to Fig. 1 an underground passageway (10) to be lined extends between a pair of manholes (12) and (14). In manhole (14) is provided an elbow pipe (16) coming out at end (18) and the top inlet end (20). To the outlet end (18) is connected a flexible first tube (22) of reinforced plastics material, the plastics material being of a type to withstand relatively high temperatures e.g. . up to one hundred degrees C. The leading end of the tube (22) is turned back upon itself and is secured to the outlet end (18) of the elbow (16), and by pouring hot water into the elbow (16) at the inlet end (20) is indicated by water inlet pipe (24), so the tube (22) is caused as shown in Fig. 1 to evert into and along the passageway toward the other man-hole. A pull rope (26) inside the tube (22) and connected to a winch (28) at ground level serves by operation of the winch (28) to assist in the eversion and the pulling of the inner section of the everting tube (22) along the passageway (10), in accordance with known practice. To the trailing end of the tube (22) is connected a p.v.c. thermo-plastic pipe (30) which is rigid, but can be bent sufficiently so as to be wound upon a'drum (32) at ground level. Depending upon the pipes rigidity, it may require to be wound onto the drum (32) when it is hot and relatively soft, and to unroll it it may also require to be heated. However, as the inversion shown in Fig. 1 proceeds, so the pipe (30) is eventually drawn into the elbow (16) and eventually into the passage (10) as shown in Fig. 2. In this connection as the water from inlet (24) is hot, as soon as the pipe (30) enters the water it will be heated, and will eventually start to soften so that it can follow the curve round the elbow (16) and can pass freely into the passageway (10). Fig. 3 shows the process at the stage where the pipe (30) has been placed in the required position inside the passageway (10), and it is now simply a matter of arranging for the pipe to be inflated or expanded up to full size, it being noted that the pipe (30) when on the drum (32) is folded for example as shown at (A) in Fig. 1 into a form of reduced overall dimensions. Pipe (30) can be expanded up to circular form and into contact with the passageway surface in view of the fact that it is soft in being immersed in the hot water inside the passageway (10), it being remembered that the pipe is of themo-plastic material. The pipe may be expanded up to the circular form by everting a second tube (34) into the trailing end of the pipe (30) as shown in Fig. 4. 5 Fig. 5 shows the arrangement wherein the tube (30) has • ^ been fully inflated onto the passageway surface. At this time, the tube (30) whilst held lining the passageway surface is cooled so that it will solidify and remain in place and so form a pipe within the 10 existing pipe. When solidification has been completed, the tube (34) and any pressurising fluid inside the passageway (10) is removed resulting in a finished lining. 15 As the pipe (30) is being expanded up to size as shown in Fig. 4, the hot water surrounding the pipe (30) is allowed to discharge either direct to waste or to a collecting base which is indicated by arrow (38) in Fig. 4. 20 As a result of the invention, an effective thermo- plastic lining pipe within an existing pipeline or passageway to rehabilitate same, is provided. 25 In relation to the method described herein certain additional features may be embodied. Thus, when the first lining tube is everted into the pipeline or passageway to pull in the thermo-plastic lining tube and hot water is used, at the end of this step the hot water 30 may be bled from the first lining tube back to the boiler and its flow may be assisted by the inward „ inversion of the expansion tube into the thermo-plastic lining tube to expand same onto the pipeline or passageway wall. Hot water again is preferably used for 35 everting the expansion tube in this way-.. At the end of this operation, the hot water inside the expansion tube may be returned to the boiler by charging cold water into the far end of the expanded lining tube, such cold water performing 2 functions namely to support the in-place and still warm lining tube and to cool that tube. By so handling the hot water for example by not discarding same, considerable heat and energy are saved. The various tubes may be everted into the pipeline or passageway from ground level using a pumping and control valve unit, the control valve unit comprising a flexible sphinkter valve which keeps the everting water under pressure, allows the tubular linings to be fed therethrough, but permits blow-off of excess pressure. Finally the use of water serves to ensure that the lining hose will be buoyantly supported as it travels along the pipeline or passageway whereby the lining of long length is easily possible.

Claims: -1- CLAIMS 1. A method of lining a pipeline or passageway surface wherein a first flexible tubular member is everted into a pipeline or passageway surface to be lined, and to the trailing end of the first flexible tube is connected the folded thermo-plastic lining pipe, so that it is pulled into the pipeline or passageway by virtue of the eversion operation, and wherein heated fluid is used for the eversion so that when the thermo-plastic pipe is completely inside the pipeline or passageway, it will be surrounded by heated fluid to soften same, following which the softened thermo- plastic pipe is inflated by fluid pressure onto the pipeline or passageway surface where it is allowed or caused to solidify in place. 2. A method according to Claim 1, wherein the first lining tube is of a material such as a fibre reinforced plastics material which is of sufficient tensile strength in order to effect the pulling into. the pipeline or passageway of the thermo-plastic tube, and also will be of sufficient heat resistance to withstand the temperature of the hot fluid which performs the eversion. 3.. A method according to Claims 1 or 2 , wherein the hot fluid is water. 4. A method according to any of Claims 1 to 3, wherein the heated thermo-plastic pipe may be inflated by any suitable means such as by pressurising the interior of the soft heated pipe, or by everting a second plastic tube into the inside of the plastic pipe. 5. A method according to Claims 1, 2, 3, or 4, wherein the plastic pipe is of p.v.c. or a polyolefin material.

Inventors: WOOD ERIC, WOOD, ERIC
Applicants: INSITUFORM GROUP LTD, INSITUFORM GROUP LIMITED
Application year: 1991
Main classification: F16L55
IPC codes: F16L55