METHOD AND DEVICE FOR THE CONSTRUCTION AND/OR THE RECONDITIONING OF PIPELINES AND CONDUITS

Abstract: A method and a device for the construction and/or the reconditioning of pipelines and conduits, by applying or forming around a sheath (309) of impervious flexible material, a tubular member (109) made from fabric or glass fibers or any other suitable material impregnated with a hardening resin (209). The thus formed impregnated tubular member (9) is expanded and shaped by means of at least one expander (1, 1′) formed by a tubular ring of resilient flexible material, of cylindrical shape, which has been pressurized so as to cause a fluid-tight squashing of its axial bore (101). By exerting a hydraulic or pneumatic pressure against one end of said expander (1, 1′), the latter is advanced along said tube (9) with a rotary-translatory motion.

Description: One of the objects of the present invention is a method of reconditioning pipes and conduits such as, for example, sewage mains, pipelines, ducts, water mains, gas mains, tunnels or the like, by lining the inner walls thereof with a tube made of fabric impregnated with a hardenable resin. Methods of lining of this type are known in the art, e.g. EP-A-260 341. All these known prior art methods have the disadvantage that, due to any unevenness in the wall of a conduit to be reconditioned, or due to curves or drain-traps along the extent of the conduit, the application of the fabric tube is difficult. A further object of the present invention is a method for the construction of new pipes and conduits, such as for instance underwater, underground or surface conduits and pipelines, by the expansion of a tubular impermeable sheath, and the concurrent lining of the external surface of said sheath by winding on it a fabric or a continuous glass fibers layer impregnated with a hardenable resin. Up today for the construction of said conduits pre-formed pipe sections are used, which are assembled together during the laying operation, or extruded pipes are used. The above prior art methods have the disadvantage, particularly with respect to the construction of underwater pipelines and conduits, that same are easily subject to the danger of failures, which could occur during the launch, especially on occasion of consistent sea waves. The present invention aims to obviate to the above and other disadvantages of the prior art methods, by providing a monolithic pipeline, exempt from joints and, as the underwater pipelines are concerned, from the danger of failures due to the sea waves. This object is achieved by an expansion device according to claim 1. According to a characteristic of the present invention, an impervious sheath of PVC or the like material, is wound on his external surface with a lining formed by a fabric and/or by continuous fibers of glass or other suitable materials, impregnated with a hardening resin. Inside of said sheath at least one expander member is inserted, which expander is formed by a tubular ring of cylindrical shape, of resilient, flexible impervious material, which is pressurized so as to cause a fluid-tight engagement of the surfaces of its inner axial bore. Thereafter a pressure is exerted by means of a pressurized fluid against one side of said expander, whereby the latter is caused to advance along the opposite side of the conduit with a rotary-traslatory motion like a cylindrical crawler track, thus exerting a uniform and homogeneous pressure against the walls of the pipeline forming sheath. The force whereby the expander presses the tube impregnated with hardenable resin may be varied by adjusting the inflating pressure of the expander. Further characteristics and advantages of the method and device according to the invention will become more apparent from the following description, made with reference to the accompanying drawings, wherein: Figure 1 is a perspective view of the expander according to the invention. Figures 2 and 3 are diagrammatic, longitudinal sectional views showing how the expander of Figure 1 behaves while being advanced in a conduit. Figure 4 shows an enlarged detail of a section of a composite tube made of a fabric and an impervious sheet, used for lining a conduit. Figure 5 shows the step of introduction of a resin-impregnated tubular member, provided with a terminal head, into the section of a conduit to be lined. Figures 6 to 8 show the three successive steps of the method of lining a section of conduit according to one embodiment of the invention. Figure 9 shows diagrammatically, in longitudinal section, the first step of the process according to another embodiment of the invention, for the construction of a new pipeline. Figure 10 is a view similar to that of Figure 9, showing an intermediate step of the process of construction of a new pipeline, and Figure 11 shows the final step of the process according to Figures 9 and 10. With reference to the drawings, and more particularly to Figures 1 to 3 thereof, the expander device 1 according to the invention comprises a tubular ring of substantially cylindrical shape, made of resilient, flexible material, impervious to air and liquids, the inner pressure of which may be raised by inflation to such a level as to cause the walls of its axial inner bore 101 to sealingly contact each other. If the expander described above is introduced sealingly into a tubular conduit 2 and a pressure P is exerted against an end thereof, e.g. by means of a pressurized fluid, the walls of the expander move with a rotary-translatory motion along the contacting side of the conduit 2 so that, for example, the hatched portions 201 (Figures 2 and 3) move from the bottom of the annular body 1 to the interior of the axial bore 101, while the portions 301 move from the opposite bottom of the annular body 1 to a position adjacent the walls of the conduit 2, with a motion similar to that of a cylindrical crawler track. Thus, the expander 1 is advanced at the desired speed and with no friction with respect to the walls of the conduit 2, from one end to the opposite end of the conduit 2. By suitably selecting the inflating pressure of the expander 1 (and, obviously, its diameter), the optimum pressure of the expander 1 against the walls of the conduit 2 may be obtained. The method of lining the walls of a conduit according to the invention will be described hereinafter with reference to Figures 5 to 8 of the accompanying drawings. With particular reference to Figure 5 of the drawings, the numeral 2 indicates the conduit section to be lined. In the illustrated case, said conduit section 2 is a portion of a sewage mains comprising a conduit section 102 upstream of the conduit section 2 and separated therefrom by a drain-trap 3 open to the exterior, and a conduit section 202 downstream of the conduit section 2 and separated therefrom by a drain-trap 103 open to the exterior, all in a thoroughly usual fashion. In the preliminary step of the operation, after thoroughly cleaning the conduit section 2, the outlet of the conduit section 102 and the inlet of the conduit section 202 are closed by pneumatic plugs 4, 5 through which there passes a respective short pipe section 6, 106 provided with a stop valve 7, 107 at the end that opens into the drain-traps 3, 103. The conduit section 2 is then flooded and the level 8 of the water depends on the level of the inlet of the valve 107 on the discharge pipe 106 which acts as a skimmer. Once the conduit section 2 has been flooded, the resin-impregnated fabric tube 9 provided with a terminal head 11 is introduced thereinto. Said tube 9, as best shown in Figure 4, comprises a layer of fabric 109 impregnated with a suitable hardenable resin 209 and provided on the inner side thereof with a tubular sheath 309 made of PVC or similar material, having the same diameter, which constitutes the element which is impervious to air and fluids. Said sheath 309, as described below, may be recovered when the conduit reconditioning operation is over. The tube 9 is impregnated with resin just before being introduced into the drain-trap 3 and then into the conduit 2, and the impregnation is carried out by means of any suitable equipment, not shown because it does not form a part of the present invention. Alternately, the tube 9 may be formed by a tubular sheath 309 of PVC or the like, lined on its outher side with one or more layers of glass fibers 109 soaked with a hardenable resin, and the said lining may be formed during the construction of the pipeline, as will be described later. Before being introduced into the drain-trap, the tube 9 is provided, preferably, with a terminal head 11 equipped with a valve 111. Once the tube 9 has been stretched in the conduit 2, the skimmer 107 will drain the flooding water from the conduit 2 via the pipe 106 during the successive working steps. Thereafter, the expander 1, which was inflated at the required operating pressure, is introduced into one end of the sheath 309 of the tube 9, and a head 10 is sealingly applied to said end of the tube 9. As shown, the head 10 is provided with a pipe 110 communicating, at one end, with the interior of the tube 9, upstream of the expander 1 and, at the other end, with the outside, for example, with the delivery side of an air compressor (not shown). The operation of the device described above is now apparent. By admitting pressure, through the pipe 110 and head 10, into the tube 9 upstream of the expander 1, the latter is pushed, as shown in Figures 7 and 8, through the entire sheath 309 of the tube 9, whereby the resin-impregnated fabric tube 109 is firmly pressed against the walls of the conduit 2. The pressurized air (or water) admitted through the pipe 110 maintains the sheath 309 under pressure also when the expander 1 has passed and, therefore, the tube 109 impregnated with resin 209 is maintained thereby adhering to the conduit 2 for the desired lapse of time. When the expander 1 arrives at the terminal plug 11, the step of expanding the fabric tube and the adhering of said tube to the inner surface of the conduit to be reconditioned is over. Once the resin 209 has cured, the expander 1, the heads 10 and 11 and possibly the sheath 309 are recovered. Having now reference to Figures 9 to 11, the embodiment of the process will be described as applied to the construction of new pipelines, and more particularly to the construction of an underwater pipeline. Numeral 12 designates a yard structure (in the example shown a self-propelled structure) housing the bobbin 13 on which the sheath 309 made of impermeable and flexible material (and for instance a PVC tubular sheath) is wound. Said sheath will constitute the inner wall of the pipe 9 which will be formed. The structure 12 houses also a device 14 for winding around the sheath 309 one (or more) layers of glass fibers, fabric or other suitable materials, soaked or impregnated with a hardenable resin, which, once the resin has cured, will form the outer strong shell 109 of the sheath 309. The device 14 may be of any suitable kind, and is shown only diagrammatically in the drawings. The sheath 309 is unwound from the bobbin 13 by a motor-driven rollers assembly 15-115, and is inserted on the leading end of the expander 1. The said expander extends, advantageously, for the whole length of the structure 12, inside of which it is supported with a slight inclination toward the bottom, by a set or supporting rollers 16, 116, 216 and its trailing end projects outside of the structure 12 through the passage 17. After having passed over the leading end of the expander 1, the sheath 309 is covered in correspondence of the intermediate portion of said expander by winding on it one or more layers 109 of glass fibers soaked with resin, after which the thus formed pipe 9 is advanced along the expander 1 to the exterior through the opening 17. Inside of the thus formed pipe a second expander 1′ is inserted, and the end of the pipe 9 is closed by means of the head piece 10. The head piece 10 is centrally bored, so as to allow the passage of the hose 110, in an air-tight manner. In the first step of the operation of the device, the hose 110 is passed through the axial passage of the expander 1′, so as to open into the space of the pipe 9 comprised between the expanders 1 and 1′. The said first step terminates when the hardening process of the resin soaking the pipe section 9 in the region of the expander 1′ is practically completed, so that the said pipe section is self-supporting. At this moment, the end of the hose 110 is withdrawn from the expander 1′, and is moved back in the direction of the head 10, so as to be arranged between the head 10 and the expander 1′, as shown in Figure 10. With the withdrawal of the hose 110, the axial inner passage of the expander 1′ is again closed in an airtigth manner, so that the expander 1 will be separated from the expander 1′ by a pipe section 9 enclosing a compressed air cushion 18, whilst the compressed air which is fed through hose 110 will now act on the rear side of the expander 1′, between the said expander 1′ and the head piece 10, thus maintaining under pressure the section of the pipe 9 which is being formed, after the movement of the expander 1′, thus assuring the perfect adherence of the sheath 309 to the outer winding 109. By proceeding in the operation of construction of the pipeline 9, the pressure acting in the pipe section between the expander 1′ and the head piece 10 will cause the expander 1′ to progress along the pipe 9. The progress of the expander 1′ will be transmitted, through the air cushion 18, to the expander 1, which will in turn "progress" along the sheating 309 which is fed by the roller 13, thus bringing forward the operation of formation of the pipeline 9, up to completion of the desired pipeline length. In Figure 11 the final step of this operation is shown, in which the leading end of the pipeline 9 has returned to the surface. In the appended claims, by the term "fabric" any fabric made of natural or artificial fibers is intended, by the term "fiber" any natural or artificial fibers are intended, either of organic or anorganic nature, like glass fibers, textile fibers, or plastics fibers, and by the term "resin" any artificial hardenable resin is intended, which may be cured at ambient conditions.

Claims: 1. An expander device (1) for the expansion of a tubular element (9) lined with a fabric or with fibers (109) soaked with a hardening resin (209), or formed by a tubular element (9) made of fabric or of fibers (109) soaked with a hardening resin (209), characterized by the fact that it comprises a tubular ring of resilient, flexible, impervious material, pressurized with air or fluids so as to cause the walls of its axial inner bore (101) to sealingly contact with each other. 2. A device according to claim 1, characterized by the fact that said tubular ring is a tubular ring of cylindrical shape. 3. A device according to the preceding claims, characterized by the fact that said tubular ring is made from a sheet of resilient, flexible, impervious, pressure-resistant material. 4. A method of reconditioning pipes and/or conduits by lining their inner walls with a tube (9) of fabric impregnated with hardenable resin, comprising the steps of: preparation of the walls of the conduit (2) to be reconditioned; impregnation of the fabric tube (9) with resin; introduction of the impregnated tube (9) into the conduit (2); introduction of an expander device (1) according to claims 1 to 3 into one end of said tube (9); arrangement of two closing heads (10, 11) at the ends of said tube (9); one of said heads, i.e. the head (10) at the end of the tube (9) bearing the expander (1) (upstream head) being provided with a pipe (110) for connection to a source of pressurized fluid, and the other head (11) (downstream head) being provided with a pipe communicating with the atmosphere; and application of a pressure through said source of pressurized fluid against an end of said expander (1) so as to advance it with a rotary-translatory motion through the entire tube (9) whereby the latter will be pressed against the walls of the conduit (2) to be reconditioned. 5. A method according to claim 4, characterized by the fact that the said downstream head (11) is applied to said tube (9) before the latter is introduced into said conduit, said downstream head (11) communicating with the atmosphere via a suitable valve (111). 6. A method according to claim 4, characterized in that inside said tube (9) of fabric impregnated with hardenable resin there is arranged an impervious tubular element (309), e.g. a PVC tube, having the same diameter as the fabric tube (109). 7. A method according to claims 4 to 6, characterized in that said fabric tube (109) is impregnated with the resin immediately before or while being introduced into the conduit (2) to be reconditioned. 8. A method according to claims 4 to 7, characterized in that prior to the introduction of said tube (109) of resin-impregnated fabric into the conduit (2) to be reconditioned, said conduit is flooded with water either partially or completely. 9. A method for the construction of underwater, underground or surface pipelines, by the expansion of an impervious tubular sheath (309), and the concurrent winding on said sheath of a fabric or of continuous fibers (109) impregnated with a hardening resin (209), comprising the steps of: insertion of two expander devices (1, 1′) of the kind according to claims 1 to 3 in said sheath (309), through its free end; closing the free end of said sheath (309) by means of a head piece (10) provided with a pipe (110) connected to a source of pressurized fluid; feeding said sheath (309) toward the leading end of said first expander device (1), whilst concurrently winding on the external surface of said sheath (309) of a lining (109) formed by a material comprising fabric and/or fibers impregnated with a hardening resin (209); applying a pressure through said source of pressurized fluid in the space of said sheath (309) between said two expander devices (1, 1′), so as to cause said two expanders (1, 1′) to be spaced by a prefixed distance by means on a compressed fluid cushion (18) during the following course of formation of the pipeline; applying a pressure through said source of pressurized fluid in the space of said sheath between said second expander (1′) and said head (10), whilst dismissing the application of pressure in the said space between said two expanders (1, 1′); maintaining the said compressed fluid cushion (18) between said two expanders (1, 1′); and prosecuting the process of feeding the sheath (309) and of winding onto said sheath of the said resin soaked material (109) up to completion of the pipeline. 10. A method according to claim 9, characterized by the fact that the winding of the sheath (309) with the resin soaked material (109) is performed in correspondence of the sheat section which is supported by the said first expander (1). 11. A method according to claims 9 and 10, in which the said impervious tubular element or sheath (309) is made from a tubular, flexible, impervious member, as for instance a PVC tubular member, having a diameter equal to the diameter of the pipeline to be made. 12. A method according to any one of the preceding claims 4 to 11, characterized by the fact that the said impervious tubular element or sheath (309) may be recovered once terminated the hardening process of the resin. 13. A method according to any one of claims 4 to 12, in which the said fibers are glass fibers. 14. A method according to any one of claims 4 to 13, in which said hardenable resin (209) is an artificial resin which may be cured at ambient conditions. 15. A method according to any one of claims 4 to 14, in which said impervious tubular element or sheath (309) is made of polyvinylchloride.

Inventors: MARINI, ERMENEGILDO, MARINI, ROBERTO
Applicants: MARINI, ERMENEGILDO, MARINI, ROBERTO
Application year: 1990
Main classification: F16L58
IPC codes: F16L55, E03F3