Abstract:
A method for effecting a repair and/or strengthening of a pipe. The method comprises cleaning an affected area of a surface of the pipe to provide a cleaned surface of the pipe surface for an area requiring repair; applying a continuous strip around the pipe from a portion prior to the affected area and allowing the continuous strip to extend to a portion after the affected area. The continuous strip forms a spiral sleeve spaced from the pipe surface to provide an annular chamber between the pipe surface and the spiral sleeve.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 12/666,610, filed Dec. 23, 2009, now U.S. Pat. No. 8,388,785, which is the U.S. National Phase of International Application No. PCT/MY2008/00058, entitled “Method for Repairing and/or Strengthening of Pipes,” filed Jun. 24, 2008, the disclosures of which are hereby incorporated by reference in their entirety. 
     FIELD OF THE INVENTION 
     The present invention relates to a method for repairing and/or strengthening of pipes and refers particularly, though not exclusively, to such a method applicable to pipes of differing diameters, and length of repair and/or strengthening. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 7,168,743 and U.S. patent application 2007/0018448 both disclose methods and apparatus for sealing terminal ends of pipe sleeves. The sleeves are used for the repairing of pipes and are generally made of metal. These pipes may be above ground or under water. In both US specifications there is disclosed the use of a sleeve  22  which is arranged to be placed surrounding the area of the pipe surface requiring repair. That means that the sleeves must be tailored to the pipes&#39; diameter, and to the length of the pipe requiring repair. As such, a large range of sleeves are required for the range of varying pipe diameters that may be used. As the repair can be over various axial lengths of the pipe, the normal method is to fabricate sleeves required for each repair. In that way the sleeves can be tailored to the length required and also the diameter required. The design and fabrication of the sleeves can sometimes take months. In that period the pipeline may need to be closed down due to the risk of failure of the pipe. This can cause significant destruction. If the pipes were carrying, for example, oil, the results of a failure of the pipe could be significant environmental damage. 
     SUMMARY OF THE INVENTION 
     According to an exemplary aspect there is provided a method for affecting a repair and/or strengthening of a pipe, the method comprises cleaning an effected area of a surface of the pipe to provide a cleaned surface of the pipe surface for an area requiring repair; applying a continuous strip around the pipe from a portion prior to the affected area and allowing the continuous strip to extend to a portion after the affected area. The continuous strip forms a spiral sleeve spaced from the pipe surface to provide an annular chamber between the pipe surface and the spiral sleeve. 
     The continuous strip may be a fibre reinforced, mechanically-sealing, polymer strip or a carbon-fibre reinforced HDPE strip. 
     The continuous strip may be formed into the spiral sleeve by at least one of: overlapping, and interlocking. 
     The annular chamber may be subsequently filled with a filling material for providing a bond between the pipe and the spiral sleeve. The filling material may be selected from the group consisting of: a structural resin, and a grout. 
     According to another exemplary aspect there is provided an apparatus for applying a continuous strip for providing repair to an affected surface area of a pipe. The apparatus comprises an application apparatus comprises at least two portions each having a plurality of rollers for guiding a continuous strip about and over the affected surface area of the pipe to form a spiral sleeve extending for at least the axial length of the affected area of the surface of the pipe; and a supply apparatus for attachment to at least one of the application apparatus portions. The supply apparatus comprises at least one driving roller for feeding the continuous strip into the at least one application apparatus portion. 
     Each of the at least two portions comprises a top plate and a bottom plate. There may be a plurality of generally equally spaced guides extending between the top plate and bottom plate. 
     At least one roller may be rotatably mounted on each of the plurality of guides adjacent a top end thereof. 
     The supply apparatus may further comprise a supply top plate and a supply bottom plate; and a plurality of drive and guide rods extending between the supply top plate and the supply bottom plate. 
     At least one of the rods may comprise rollers and may be adapted to be driven by a drive system. 
     The drive system may comprise a sprocket above supply top plate and securely attached to an upper end of the at least one of the rods for driving the at least one of the rods to a rotate about its longitudinal axis. 
     The drive system may be configured to drive the rods and rollers to enable the continuous strip to be fed through the supply apparatus into the at least two portions of the application apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a damaged pipe; 
         FIG. 2  is a perspective view at a first stage in the repair process; 
         FIG. 3  is a view corresponding to  FIG. 2  at a second stage in the repair process; 
         FIG. 4  is a view corresponding to  FIGS. 2 and 3  at a third stage in the repair process; 
         FIG. 5  is a view corresponding to  FIGS. 2 to 4  at a fourth stage in the repair process; 
         FIG. 6  is a view corresponding to  FIGS. 2 to 5  at a fifth stage in the repair process; 
         FIG. 7  is a front view of the damaged pipe of  FIG. 1  having a spiral sleeve thereon; 
         FIG. 8  is a perspective view  FIG. 7 ; 
         FIG. 9  is a schematic cross-sectional view of an end cap sealed to the spiral sleeve and damaged pipe of  FIG. 7 ; 
         FIG. 10  is a schematic plan view of a connecting portion of the end cap of  FIG. 9 , 
         FIG. 11  is a transverse cross-sectional view of the pipe of  FIG. 7  at X; 
         FIG. 12  is a longitudinal cross-sectional view of the pipe of  FIG. 8  at Y; 
         FIG. 13  is a close-up view of the pipe of  FIG. 12  showing a spacer; 
         FIG. 14  is a side view of the spacer of  FIG. 13 ; and 
         FIG. 15  is a plan view of the spacer of  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIG. 1  there is a pipe  10  in need of repair. The preliminary step of preparing the pipe  10  for repair is in accordance with the known techniques of abrasive or high pressure water blasting to remove rust and remainders of all coatings, to expose the bare metal on the surface of the pipe, and so forth. The abrasive blasting of the pipe  10  may be carried out by sweep blasting using fine blast not containing iron (for example, garnet, aluminium oxide and, copper slag), glass pearls or stainless steel shot. The maximum speed of cleaning and the most effective cleaning is obtained by systematic blasting. Work is blocked out in 30 cm squares and each square is blasted evenly until complete. A minimum of 25 mm into any adjacent coated area is continued by blasting and the edges are feathered. 
     Subject to the condition of the pipe  10 , composite reinforcement extending longitudinally of the pipe may be placed at a pre-determined spacing around the outer surface of the pipe  10 . 
     To now refer to  FIG. 2 , there is shown one exemplary embodiment of the present invention. In this case a first portion of an application apparatus  12  is placed adjacent to the pipe  10 . The application apparatus  12  is an arcuate portion that partially surrounds the pipe  10 . It may be for 180 degrees of the pipe as shown, or may be for a lesser segment. The first portion  12  may be substantially rigid or may be in a number of segments that are mutually pivotally attached so that the first portion  12  can be used for pipes of varying diameters. Alternatively, the first portion  12  may be for a pipe  10  of predetermined diameter and may extend around the pipe for 180 degrees. The diameter of the first portion  12  may vary with the diameter of the various pipes. 
     The first portion  12  has a top plate  14  and a bottom plate  16 . Extending between the top plate  14  and bottom plate  16  are a plurality of generally equally spaced guides  18 . Rotatably mounted on each of the guides  18  adjacent a top end thereof are a plurality of rollers  20 . Instead of a plurality of individual rollers  20 , a large, single, roller may be provided or a smaller number of intermediate size rollers. The rollers  20  extend for a portion of the axial length of the guides  18  and are retained adjacent the upper end of the guides  18 . 
     As shown in  FIG. 3  a second portion  22  of the application apparatus is then placed in position and aligned with and secured to or with the first portion  12 . The second portion  22  again has a top plate  24  and a bottom plate  26  with guides  28  extending between them and being generally equally spaced. The guides  28  also have rollers  30  adjacent the upper end. In essence, the second portion  22  is substantially identical to the first portion  12 . 
     For varying pipe diameters the second portion  22  may be in a number of segments that are mutually pivotally attached. In that way they can be opened or closed as required to accommodate pipes of varying diameters. Naturally, for large diameter pipes, more than the two portions  12 ,  22  may be required. 
     Attached to the second attachment portion  22  is a supply apparatus  32 . The supply apparatus  32  comprises a top plate  34  and a bottom plate  36 . Extending between the top plate  34  and the bottom plate  36  are a plurality of drive and guide rods  38 . On some or all of the rods  38  are rollers  40 . Each of the rods  38  is adapted to be driven by a drive system  42  that comprises a sprocket  44  above top plate  34  but securely attached to the upper end of each rod  38 . Each sprocket  44  is to drive the rod  38  to rotate about its longitudinal axis. To drive the sprockets a chain  46  is provided. One rod  48  of the rods  38  may contain a drive system (not shown) such as, for example, an electrical air driven motor, a reduction gearbox and a battery. Any suitable drive system may be used. It may be able to operate on its own or may have an external power source (not shown). 
     The drive system  42  is intended to drive the rods  38  and rollers  40  to enable a strip  50  to be fed through the supply apparatus  42  into the two portions  12 ,  22  of the application apparatus. 
     The strip  50  is a continuous, fibre reinforced, mechanically sealing, polymer strip. For example, the strip  50  may be a carbon-fibre reinforced HDPE strip. As shown in  FIGS. 4 to 6 , the strip  50  is fed through the supply apparatus  32  driven by the duct system  42 . It feeds between the rods  38 , with the rods being located on either side of the longitudinal axis of the supply apparatus  32  in an alternating sequence. The strip  50  is wound around the pipe  10  and forms a continuous, overlapping or mechanically interlocking spiral sleeve  52  around the pipe  10 . As the strip  50  forms the spiral sleeve  52 , the spiral sleeve  52  will be pulled under gravity from the attachment portions  12 ,  22 . This is because the spiral sleeve  52  is not vertically constrained due to the internal diameter of bottom plate  26  and top plate  24  being equivalent to the external diameter of the spiral sleeve  52 . For horizontally disposed pipes, the spiral sleeve  52  can still be formed without gravitational pull because feeding of the strip  50  is actively driven by the drive system  42 . The feed of the strip  50  may be such as to form the spiral sleeve  52  by being at an appropriate angle. This would also assist in forming the spiral sleeve  52  when the pipe  10  is not vertical. Therefore, the spiral sleeve  52  of the strip  50  will be wrapped around the pipe  10  forming a sleeve  52  surrounding the damaged portion of pipe  10 —that portion requiring repair. The preferably, the spiral sleeve  52  starts from before and extends beyond the damaged portion of the pipe  10  to cater for the transfer of the actual loads to the pipe  10 . 
     Both ends of the spiral sleeve  52  may be provided with an end cap  70 , sealed to the spiral sleeve  52  as shown in  FIGS. 7 to 9 . The caps are preferably made of PE, and contain an inlet  72  port and an outlet port  74  that may, for example, be in accordance with the U.S. Pat. No. 7,168,743 or the U.S. patent application 2007/0018448 mentioned earlier. Seals such as, for example, “Teflon” seals  78 , are preferably provided between the end cap  70  and the spiral sleeve  52 , and between the end cap  70  and the pipe  10 . The end cap  70  preferably has a general form of a flexible split ring for fitting around the pipe  10 , and secured by a connector such as, for example, a PVC or PE connector  76 , as shown in plan view in  FIG. 10 . 
     The spiral sleeve  52  is dimensioned in diameter to form an annular chamber  80  between the pipe  10  and the spiral sleeve  52 , as shown in  FIGS. 11 and 12 . That annular chamber  80  will typically range from 25 to 50 mm in radial extent between the outer surface of the pipe  10  and the inner surface of the spiral sleeve  52 . The radial size of the annular chamber  80  will depend upon the service condition of the affected area of the pipe  10  such as, for example, dents, wall protrusions, the out of roundness of the pipe, and the volume of the longitudinal reinforcement required. The annular chamber  80  is preferably secured by installing spacers such as, for example, polymer spacers  82 , between the spiral sleeve  52  and the pipe  10 . Each polymer spacer  82  is preferably Y-shaped with 2 arms  85  and a leg  88 . Each arm  85  comprises an angled end  86  for engaging a barbed spike  90  each. The barbed spike  90  preferably has a plurality of tiers of barbs like a miniature Christmas tree. The barbed spikes  90  serve to hold the strip  50  in place. The spacers  82  are preferably manually inserted by clipping each spacer  82  between two barbed spikes  90  during winding of the strip  50  to form the spiral sleeve  52 . For a spiral sleeves  52  having a diameter of up to about 20 to 24 inches and a length not exceeding 3 to 4 m, spacers  82  will not be required because the spiral sleeve  52  will be sufficiently rigid) so as to be correctly spaced around the pipe automatically during winding of the strip  50 . Installation of the end caps  70  further ensures rigidity of the spiral sleeve  52  and correct spacing of the spiral sleeve  52  from the pipe  10  to form the annular chamber  80 . 
     When the spiral sleeve  52  is complete, water present in the annular chamber  80  will be discharged by means of the application of compressed air or other gas entering through the inlet port  72  and allowing discharge through the outlet port  74 . The annular chamber  80  can then be flushed with fresh water and the fresh water removed by use of air or an inert gas. The annular chamber  80  is then filled with a known structural resin or grout  84  in accordance with known techniques providing a bond between the pipe  10  and the spiral sleeve  52  by bonding to both the pipe  10  as well as the spiral sleeve  52 . The barbed spikes  90  further anchor the spiral sleeve  52  into the structural resin or grout  84 . The attachment portions  12 ,  20  and supply system  32  can then be removed and the pipe repair completed. Preferably, the attachment portions  12 ,  20  are removed upon installation of the bottom end cap  70 . The spiral sleeve  52  is left in position to provide an external, strengthening and protecting layer over the structural resin or grout  84 . 
     Whilst there has been described in the foregoing description exemplary embodiments, it will be understood by those skilled in the technology concerned that many variations in details of design, construction and/or operation may be made without departing from the present invention.