VARIABLE ANGULAR INSERTION METHOD FOR LINING TUBULAR MEMBERS

Abstract: A method for lining a tubular member with an elastomeric liner having an outside diameter which is initially greater than the inside diameter of the tubular member. A series of downsizing rollers (37, 57, 59, 61, 63) reduce the outside diameter of the liner a preselected amount. A series of shaping rollers (65, 84, 85) from the downsized liner into an ellipse, thereby allowing the downsized liner to be guided around bends and turns into the interior of the tubular member. After insertion, the liner is allowed to expand to substantially its original outside diameter to secure the liner within the tubular member.

Description: VARIABLE ANGULAR INSERTION METHOD FOR LINING TUBULAR MEMBERS BACKGROUND OF THE INVENTION Field of the Invention The present invention relates generally to a method for lining a tubular member, such as a chemical pipeline, with a synthetic liner, the liner being fed along a variable angular path to the interior of the pipe to be lined and being secured within the pipe interior without the necessity of heat, vacuum or chemical bonding agents. Description of the Prior Art Fluid carrying pipes are often subject to deterioration, corrosion and other conditions which are detrimental to the life of the pipe or to the fluids moving through the pipe. This problem is particularly acute in many chemical process industries where caustic chemicals are being transported through pipelines. Modern chemical plants often include miles of pipeline subject to corrosion and deterioration. The pipelines needing lining may be buried below ground, elevated above ground, or be in storage racks. Other chemical pipelines which are encompassed by the present invention include sewer pipes, water mains or gas mains, where foreign agents such as plant roots often break through the pipe wall and intrude into the pipe interior, thereby destroying the integrity of the pipe. Other factors such as differential pressures internally and externally of the pipe, erosion or earth movements can form leaks in the pipework which must be repaired. If excavating, uncoupling, replacing and backfilling of the pipework is required, the process is usually time consuming and expensive. An alternative solution is to provide an internal lining to the pipework to remedy leakage problems. Although plastic inserts have been used in the past for protective purposes, their use has generally involved cumbersome and difficult procedures for effectively installing such liners, and particularly in sealing them to the wall of the pipe. U.S. Patent No. 3,494,813, to Lawrence et al., issued February 10, 1970, shows a method for installing a plastic liner in a pipe by using vacuum to draw the liner into the pipe and to assure tight sealing engagement between the liner and the pipe wall. U.S. Patent No. 1,708,141, to Kepler, issued April 9, 1929, shows a method of lining a pipe with an elastomeric lining in which the lining is pushed through a reducing die and coated with cement. U.S. Patent No. 3,462,825, to Pope et al., issued August 26, 1969, shows a method for lining a tubular member with a fluorocarbon liner having an initial outside diameter greater than the inside diameter of the tubular member. The liner is placed in the tubular member by gripping one end of the liner and pulling it through a reducing die and into the tubular member. The liner is then released, allowing it to expand into engagement with the inner wall of the tubular member. British application, GB 2084686, filed September 25, 1990, shows a method for lining sewer pipes in which a liner is pushed through downsizing rollers and fed into the pipe with heat being used to cause reverse expansion of the liner. Since the liner is fed approximately linearly into the underground pipe, it was necessary to excavate a sizeable opening in the surface of the ground for feeding the liner into the pipe interior. None of the above methods succeed in providing an improved method for lining a tubular member with a synthetic liner in which the primary mechanism for securing the liner within the tubular member is the radial pressure exerted on the tubular member by the synthetic liner, the liner being in a state of circumferential compression within the surrounding tubular member when installed. None of the above methods provides a convenient method for installing a liner in a tubular member wherein the liner is fed in a variable angular path toward the tubular member to be lined to thereby facilitate the lining of tubular members which are located below ground, or at various elevations above ground. A need exists, therefore for a method for lining chemical or other pipelines in which the liner is installed without the use of chemical bonding agents and without the use of heat or vacuum pressure. A need also exists for a method for lining an underground pipe which requires minimum excavation of the ground surface surrounding the point of liner insertion into the interior of the pipe. A need also exists for a method for lining chemical or other pipelines which allows the liner to be guided through a variety of angular orientations toward the interior of the pipeline to be lined. SUMMARY OF THE INVENTION In the method of the invention, a tubular member is lined with a generally cylindrical, elastomeric liner having an outside diameter which is initially greater than the inside diameter of the tubular member. A length of the generally cylindrical liner is first reduced to a downsized outside diameter by feeding a length of the liner to a set of downsizing rollers. The length of downsized, generally cylindrical liner which exits the downsizing rollers is passed through a set of shaping rollers which reform the external configuration of the liner to a shape particularly adapted for variable angular bends. Preferably, the shaping rollers provide the liner with an elliptical shape. The elliptically shaped liner is then fed through one or more sets of orienting rollers which guide the liner toward the mouth of the tubular member to be lined. In the case of an underground tubular member, such as a sewer pipe, the elliptically shaped liner is fed through a first set of orienting rollers which guide the elliptically shaped liner through a first 90" turn. The elliptically shaped liner is then fed through a second set of orienting rollers which guide the elliptically shaped liner through a second 90° turn, whereby the length of elliptically shaped liner exiting the second set of orienting rollers is oriented in a plane generally parallel to the surface of the ground and aligned with the open interior of the underground tubular member to be lined. The elliptically shaped liner is then passed through a set of reshaping rollers which return the length of liner to a generally cylindrical, downsized external diameter. The downsized liner is then inserted into the tubular member to be lined and is allowed to expand to substantially its original outside diameter to thereby secure the liner within the tubular member. By varying the angular orientation of the elliptically shaped liner exiting the orienting rollers, the liner can be fed toward above ground pipes which are located at various elevations, including pipe mounted in structural storage racks. Additional objects, features, and advantages will be apparent in the written description which follows. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a simplified, schematic view illustrating the variable angular insertion of a liner into a tubular member using the method of the invention; Figures 2-4 are isolated, schematic views illustrating various arrangements of downsizing rollers used in practicing the method of the invention; Figure 5 is an enlarged view, partially in section, of the insertion apparatus used in practicing the method of the invention; Figure 6 is an isolated view of the downsizing rollers, taken along lines VI.-VI. in Figure 5; Figure 7 is an isolated view of the downsizing rollers, taken along lines VII.-VII. in Figure 5; Figure 8 is an isolated view of the downsizing rollers, taken along lines VIII.-VIII. in Figure 5; Figure 9 is an isolated view of the downsizing rollers, taken along lines IX.-IX. in Figure 5; Figure 10 is an isolated view of the downsizing rollers, taken along lines X.-X. in Figure 5; Figure 11 is an isolated view of the downsizing rollers, taken along lines XI.-XI. in Figure 5; Figure 12 is an enlarged, partial sectional view of a pulling apparatus used in the method of the invention; Figure 13 is an isolated view of the rotatable carriage which houses the shaping rollers used in the method of the invention; and Figure 14 is a simplified end view of the rotatable carriage, taken along lines XIV.-XIV. in Figure 13 illustrating the various angular orientations which are possible for the elliptically shaped liner which is exiting the rotatable carriage. DETAILED DESCRIPTION OF THE INVENTION Figure 1 is a simplified, schematic view of the steps and apparatus used in the method of the invention. A length of elastomeric liner 11 is fed from a pre-welded supply (not shown) through the insertion apparatus 15 to the tubular member 17 to be lined. The tubular member 17 can be, for instance, a cylindrical conduit such as a sewer pipe, water main, gas main or chemical process line which extends horizontally in the ground 19. As will be apparent in the description which follows, the method can be used to line an above ground pipe as well, such as a fluid transport pipeline in a chemical plant or joints of pipe stored at an elevated location in a storage rack. The elastomeric liner 11 can be any synthetic elastomer which initially has an outside diameter greater than the inside diameter of the tubular member 17 and which can be downsized and returned to substantially its original outside diameter according to the method of the invention. Preferred liner materials include polyolefin materials, with the preferred material being commercially available polyethylene pipe. It is preferred that the polyethylene pipe be of about 3% to 5% greater initial outside diameter than the tubular member to be lined. An increase in initial outside diameter of the liner increases the force necessary to downsize the liner. As a result, a liner having only slightly greater outside diameter than the tubular member 17 to be lined is preferred. The wall thickness of the liner is not critical, so long as it is great enough to permit the liner to be downsized without distortion or irregular deflection of the liner material. In the embodiment of the invention shown in Figure 1, the liner 11 has a leading end 19 with a pulling head 21 secured thereto, the pulling head 21 being attached to a cable 23 which runs to a pulling unit 25 located at the surface of the ground 27. The pulling unit 25 is located adjacent a manhole opening 29 which provides access to the sewer pipe 17. The insertion unit 15 is located adjacent an insertion opening 31 which has been formed by excavating a manhole opening 33 in a generally vertical plane with respect to the surface of the ground 27. Figure 5 shows the insertion apparatus in greater detail. The insertion apparatus 15 includes a platform trailer 35 having means provided thereon for reducing a length of the generally cylindrical liner 11 to a downsized outside diameter by feeding the length of liner 11 in a horizontal plane which generally parallels the surface of the ground 27. Preferably, the downsizing means includes one or more sets of downsizing rollers 37 at a rolling station 39. The sets of downsizing rollers are arranged in a common plane (indicated by the axis 99 in Figure 5) which defines a first path of travel for the cylindrical liner. Insertion unit 15 is equipped with a drive motor 16 which is selectively engaged to drive downsizing rollers 37 for advancing liner 11 through insertion unit 15. It may be desirable to advance liner 11 by driving down sizing rollers 37 for long lengths of liner 11. Additionally, when installation is such that pulling unit 25 cannot be utilized, liner 11 is then advanced by driving downsizing rollers 37. Generally, only the last set of downsizing rollers, such as rollers 63, or roller 63 and 61 will be driven. These rollers may be driven alone or in combination with pulling unit 25 to push and pull liner 11 forward through insertion unit 15. Figure 6 shows the first set of downsizing rollers 37 in isolated fashion for ease of illustration. Each set of downsizing rollers includes three or more hemispherical rollers which are provided in sets. In the embodiment of Figure 6, the downsizing roller set 37 includes four hemispherical rollers 41, 43, 45, 47 which are offset at equal increments (in this case 90") about the exterior of the liner 11. Each of the downsizing rollers 37 has an axis at rotation 49, 51 which intersects at the midpoint 53 of a liner receiving opening 54 and which defines a 360° region of contact with the exterior of the liner 11 being fed through the liner receiving opening. Each hemispherical roller 41 is rotatable about a shaft 55 mounted on the frame of the rolling station 39 by a suitable flange. In the example shown in Figure 6, each roller 41, 43, 45, 47 has a central axis of rotation 49, 51 which forms a 90° angle with the next adjacent roller and which intersects at the midpoint 53 of the liner receiving opening. However, as shown in Figures 2-4, the number of downsizing rollers in each roller set can vary, depending upon the outside diameter of the liner being handled. Generally, as the diameter of the pipe being rolled increases, the number of rollers spaced around the pipe outer diameter must also increase to produce a linear elongation in the liner whereby the liner maintains a standard dimensional ratio in the downsized condition and distortion of the liner is minimized or eliminated. For four inch polyethylene pipe (Figure 2) , a four roller system has proved satisfactory, each roller having a large outside diameter at its midpoint. For an 8" pipe (Figure 3) , a six roller system has been used advantageously. For a 16" pipe (Figure 4), an eight roller system has proved satisfactory. As shown in Figure 5, downsizing roller sets 57, 59, 61 and 63 are also mounted in the rolling station along the longitudinal axis defined by the midpoint 53 of the liner receiving opening (Figure 6) . Each of the roller sets is identical in construction and arrangement to that of the first roller set 37 shown in Figure 4. However, each of the roller sets is machined to provide a progressively smaller liner receiving opening. For instance, in the embodiment shown in Figure 5, the first roller set 37 provides a 2% reduction in the original outside diameter of the liner 11 with the roller set 59 providing a 4% reduction and the roller set 63 providing a 6% reduction in the original outside diameter of the liner 11. The progressive downsizing of the liner is illustrated in simplified fashion in Figures 4-6. As shown in Figures 5-7, the downsizing roller sets 57 and 61 are also rotated 45° about the longitudinal axis defined by the midpoint 53. It will be understood that various degrees or percentages of downsizing may be required. The liner 11 next passes through a forming means, such as shaping rollers 65, which provide the liner 11 with an external configuration adapted to the passed around variable angular bends or corners in the insertion path. As shown in Figure 8, each set of shaping rollers 65 preferably includes at least first and second shaping rollers 67, 69 mounted on shafts 71, 73 of the shaping rollers 67, 69 are located in parallel planes. Each of the shaping rollers 67, 69 has a common axis of rotation 75 (Figure 8) which intersects the midpoint 53 of the liner receiving opening to define a partial region of contact with the liner being fed through the liner receiving opening. Preferably, the shaping rollers 67, 69 provide the liner 11 with an elliptical shape. By "elliptical" is meant that the ultimate shape of the liner 11 exiting the last set of shaping rollers 85 is defined by the path of a point that moves so that the sum of its distances from two fixed points called foci (87, 89 in Figure 10) is constant. The shape is also the same as that defined by the closed curve produced when a cone is cut by a plane inclined obliquely to the axis and not touching the base. The elliptically shaped liner 91 (Figure 10) exiting the shaping rollers is then fed through an orienting means, such as the first set of orienting rollers 93, which guide the elliptically shaped liner 91 along a second path of travel, the second path of travel being in a different plane from the first path of travel defined by the axis 99. This second path of travel will generally be at an angle ranging from about 10 to 90° from the plane of the axis 99. In the example illustrated in Figure 5, the first set of orienting rollers 93 guide the liner 91 through a first 90° turn. The orienting rollers 93 are rotatably mounted within a frame or track 95 which is supported on the rear of the platform trailer 35 and which is extendible by means of a hydraulic cylinder 97 between the vertical position shown in Figure 5 and a generally horizontal, transport position. After passing through the first set of orienting rollers 93, the elliptically shaped liner 91 is oriented in a vertical plane which is approximately normal to the horizontal plane 99 (Figure 5) which intersects the midpoint 53 of the liner receiving openings of the downsizing rollers 37. The elliptically shaped liner 91 is then fed through a second set of orienting rollers 101 which guide the elliptically shaped liner through a second 90° turn, whereby the length of elliptically shaped liner 92 exiting the second set of orienting rollers is again oriented in a plane 103 which is generally parallel to the horizontal plane 99 and to the surface of the ground 27. The elliptically shaped liner 91 is then passed through reshaping means, including the set of reshaping rollers 105 (Figure 11) located within the manhole opening 33 adjacent the opening 107 into the interior 109 of the sewer pipe 17 to be lined. Each reshaping roller set 105 making up the reshaping means is preferably made up of two reshaping rollers 106, 108 (Figure 11) which are rotated 45° about the midpoint 53 from the position of the last set of shaping rollers 85. Each reshaping roller 106, 108 is made up of oppositely extending frusto conical portions 110, 112 which are joined at a cylindrical mid region 114. The reshaping rollers 105 are oriented to provide the length of liner 111 exiting the reshaping rollers 105 with a generally cylindrical, downsized external diameter. Figure 11 shows the length of liner 91 regaining its cylindrical shape. The generally cylindrical, downsized liner is inserted within the sewer pipe 13 by attaching a suitable pulling head 21 and cable 23, the cable 23 being passed around a sheave 113 (Figure 12) to the pulling unit 25 located adjacent the first manhole opening 29 at the surface of the ground. After pulling the leading end 19 of the liner through the interior 109 of the sewer pipe 17, the downsized liner is allowed to expand to substantially its original outside diameter to thereby secure the liner within the tubular member 17. As shown in Figure 13, the forming means of insertion apparatus 15 is preferably provided as a rotatable carriage 119. The rotatable carriage 119 includes a cylindrical housing 121 which contains the shaping rollers 65. The cylindrical housing 121 is mounted on support posts 123, 125 having yokes 126, 128 and roller means 127, 129 for allowing rotation of the housing about horizontal axis 131. The housing 121 has a leading end 133 which includes a flange 135. Flange 135 can be engaged, as by bolts 138, with a mating flange 137 of the stationary, trailing end 139 of the rolling station 39. Removing the bolts 138 allows the housing 121 to be rotated thru, for instance, 30° increments before again being bolted to the stationary flange 137. In this way, the elliptically shaped liner 91 exiting the rotatable carriage can be fed thru a variety of angular insertion paths (illustrated by dotted lines in Figure 14) toward, for instance, an above ground pipeline or a joint of pipe located within an elevated storage rack. Preferably, the synthetic elastomer selected for use as the liner 11 has known reverse expansion characteristics. The degree of elongation which is effected by passing the liner through the downsizing rollers 41, 43, 45, 47 is calculated to allow insertion of the liner within the tubular member 17. Reverse expansion of the liner 11 serves to tightly engage the liner within the internal diameter of the tubular member. As an example of the present method, a sewer pipe having an inside diameter of 7 5/8 inches was lined according to the method of the invention. The liner was a polyethylene pipe having an initial outside diameter of 8 inches with a wall thickness of 0.246 inches. The percentage reduction in outside diameter of the liner is shown in Table I as it passed through the sets of reducing rollers. TABLE I 8.00 inch polyethylene liner (all dimensions in inches) The reduced liner 11 will attempt to return to its approximate original outside dimensions until it comes into contact with the internal diameter of the host pipe and will securely bond within the interior of the pipe 17 within a short time. An invention has been provided with several advantages. Because the reverse expansion characteristics or "memory" of the liner 11 are known, the liner returns to a pre¬ determined size to fill out and conform to the internal diameter of the tubular member 17 without the use of heat or chemical bonding agents. The use of shaping rollers to provide the initially cylindrical liner with a generally elliptical shape has been found to facilitate angular insertion, including 90° turns in the path of the liner being fed to the tubular member to be lined. By properly arranging and sizing the downsizing roller set, the standard dimensional ratio of the liner can be maintained in the downsized condition so that a more linear elongation of the liner is achieved. Because a nearly perfect linear expansion of the liner results, a more uniform contact can be achieved within the internal diameter of the tubular member as the liner reversely expands free from any mechanically induced stress. Because the liner can be fed through various angular orientations on its path toward the opening of the tubular member to be lined, both above and below ground pipes can be lines with a minimum of effort. In the case of sewer pipes, the amount of excavation required at the manhole opening is minimized, thereby saving time and minimizing the disruption of the ground surface. While the invention has been shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit thereof.

Claims: CLAIMS WHAT IS CLAIMED IS: 1. A method of lining a tubular member with a generally cylindrical, elastomeric liner having an outside diameter which is initially greater than the inside diameter of the tubular member, the method comprising the steps of: reducing a length of the generally cylindrical liner to a downsized outside diameter by feeding a length of the liner to a set of downsizing rollers which are arranged in a common plane defining a first path of travel; passing the length of downsized generally cylindrical liner which exits the downsizing rollers through a set of shaping rollers which provide the liner with an elliptical shape; feeding the elliptically shaped liner through an orienting means for guiding the elliptically shaped liner along a second path of travel, the second path of travel being in a different plane from the first path of travel; passing the elliptically shaped liner through a set of reshaping rollers which again provide the length of liner with a generally cylindrical, downsized external diameter; inserting the downsized liner into the tubular member to be lined; allowing the downsized liner to expand to substantially its original outside diameter to thereby secure the liner within the tubular member. 2. A method of lining a tubular member with a generally cylindrical, elastomeric liner having an outside diameter which is initially greater then the inside diameter of the tubular member, the method comprising the steps of: reducing a length of the generally cylindrical liner to a downsized outside diameter by feeding a length of the liner to a set of downsizing rollers which are arranged in a common plane defining a first path of travel, the liner being reduced in outside diameter a preselected amount to thereby effect a linear elongation of the liner, and whereby the liner retains a standard dimensional ratio in the downsized condition; passing the length of downsized generally cylindrical liner which exits the downsizing rollers through a set of shaping rollers which provide the liner with an elliptical shape; feeding the elliptically shaped liner through an orienting means for guiding the elliptically shaped liner along a second path of travel, the second path of travel being in a different plane from the first path of travel; passing the elliptically shaped liner through a set of reshaping rollers which again provide the length of liner with a generally cylindrical, downsized external diameter; inserting the downsized liner into the tubular member to be lined; allowing the downsized liner to expand to substantially its original outside diameter to thereby secure the liner within the tubular member. 3. The method of claim 2, wherein the synthetic elastomer selected for use as the liner has known reverse expansion characteristics and wherein the degree of elongation which is effected is calculated to allow insertion of the liner within the tubular member, reverse expansion of the liner serving to tightly engage the liner within the internal diameter of the tubular member. 4. The method of claim 3, wherein the synthetic elastomer selected is a polyolefin. 5. The method of claim 4, wherein the polyolefin is polyethylene. 6. The method of claim 3, wherein the downsizing rollers are hemispherical rollers which are provided in sets, each set being made up of a plurality of rollers which are offset at equal increments, each of the rollers having an axis of rotation which intersects at the midpoint of a liner receiving opening and which defines a 360° region of contact with the liner being fed through the liner receiving opening. 7. The method of claim 6, wherein the shaping rollers are provided in sets, each set of shaping rollers including at least first and second rollers mounted on a shafts of opposite sides of the liner, the shafts of the sets of rollers being located in parallel planes, and wherein each of the shaping rollers has a common axis of rotation which intersects the midpoint of the liner receiving opening to define a partial region of contact with the liner being fed through the liner receiving opening. 8. A method of lining a sewer pipe having an opening interior which extends horizontally in the ground with a generally cylindrical, elastomeric liner having a leading end an a trailing end and an outside diameter which is initially greater than the inside diameter of the sewer pipe, the method comprising the steps of: reducing a length of the generally cylindrical liner to a downsized outside diameter by feeding the leading end of the liner in a horizontal plane which generally parallels the surface of the ground to a set of downsizing rollers, the liner being reduced in outside diameter a preselected amount to thereby effect a linear elongation of the liner, and whereby the liner retains a standard dimensional ratio in the downsized condition; passing the leading end of downsized generally cylindrical liner which exits the downsizing rollers through a set of shaping rollers which provide the liner with an elliptical shape; feeding the elliptically shaped liner through a first set of orienting rollers which guide the elliptically shaped liner through a first 90° turn; feeding the elliptically shaped liner through a second set of orienting rollers which guide the elliptically shaped liner through a second 90° turn, whereby the length of elliptically shaped liner exiting the second set of orienting rollers is again oriented in a plane generally parallel to the surface of the ground, the leading end of the liner being aligned with the sewer pipe to be lined; passing the elliptically shaped liner through a set of reshaping rollers which again provide the liner with a generally cylindrical, downsized external diameter; attaching a pulling head to the leading end of the liner and pulling the liner through the interior of the sewer pipe to be lined; allowing the downsized liner to expand to substantially its original outside diameter to thereby secure the liner within the sewer pipe. 9. The method of lining a sewer pipe of claim 8, wherein the downsizing rollers are hemispherical rollers which are provided in sets, each set being made up of at least four rollers which are offset at equal increments, each of the rollers having an axis of rotation which intersects at the midpoint of a liner receiving opening, thereby defining a 360° region of contact with the liner being fed through the liner receiving opening. 10. The method of claim 9, wherein the shaping rollers are provided in sets, each set of shaping rollers including at least one roller mounted on a shaft on an opposite side of the liner, the shafts of the sets of rollers being located in parallel planes, and wherein each of the shaping rollers has an axis of rotation which intersects at the midpoint of a liner receiving opening to define a partial region of contact with the liner being fed through the liner receiving opening.

Inventors: MCMILLAN JIM S, TARSHA SIMON A, MCMILLAN, JIM, S., TARSHA, SIMON, A.
Applicants: PIPE REHAB INT INC, PIPE REHAB INT.'L, INC.
Application year: 1992
Main classification: F16L58
IPC codes: B21C37, B29C53, B29C63, F16L55, F16L58