Patent Publication Number: US-7216674-B2

Title: Installation assemblies for pipeline liners, pipeline liners and methods for installing the same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is related to and claims the benefit under 35 U.S.C. §119 and 35 U.S.C. §365 of International Application No. PCT/CA02/01480, filed Oct. 3, 2002. This is a continuation of U.S. patent application Ser. No. 09/972,184 filed Oct. 5, 2001, now U.S. Pat. No. 6,691,741. 

   TECHNICAL FIELD 
   The present invention relates to pipeline repair and/or reinforcement and in particular to installation assemblies for pipeline liners, pipeline liners per se and methods for installing pipeline liners. 
   BACKGROUND ART 
   Pipeline liners are often used to repair and/or reinforce ruptured or weak areas in pipeline networks such as sewer systems and the like. There are many disadvantages associated with current methods of installing pipeline liners. 
   Pipeline liners for constant or variable diameter pipelines are typically installed using bladder systems. During installation of a pipeline liner, the bladder system is inflated to expand the pipeline liner and force it against the interior surface of the pipeline. The pipeline liner is then allowed to cure against the inner wall of the pipeline. Current bladder systems require pipeline access at the location that is to be repaired or re-enforced. Gaining access to a particular pipeline location can be difficult. Additional labor is required because the pipeline must be excavated in order to gain access at the desired location. 
   It is also not uncommon for a pipeline to vary in diameter along its length. Such an in-line transition in pipeline size has traditionally made it necessary for technicians to excavate at the transition point in order to install a pipeline liner. Although, expandable pipeline liner materials that accommodate the varying diameter of a pipeline are currently available, these materials become thinner when they expand to larger diameters. As a result larger diameter sections of pipelines end up with a sub standard repair because there is not enough pipeline liner material to give it strength. 
   Another difficult area of pipelines to repair or re-enforce is the T-junction between a main pipe to a lateral line. These junctions are typically the weakest joints in pipeline systems. Therefore, lining of these junctions is common. Current pipeline liners for T-junctions are difficult to install and require multiple steps, thus making the installation procedure time consuming for technicians. As will be appreciated, improvements to pipeline liner installation assemblies, pipeline liners and methods of installing the same are desired. 
   It is therefore an object of the present invention to obviate or mitigate at least one of the above described disadvantages. 
   DISCLOSURE OF THE INVENTION 
   According to one aspect of the present invention there is provided an installation assembly for installing a liner in a pipeline, said installation assembly comprising: 
   a bladder assembly to be inserted into a liner, said bladder assembly including:
         an inflatable inner bladder having an installation end and a retrieval end and defining an internal reservoir; and   an outer bladder surrounding said inner bladder at least along a portion of the length thereof, said outer bladder having an end coupled to said inner bladder adjacent said installation end;       

   a fluid passage coupled to said inner bladder, said fluid passage for introducing fluid into said internal reservoir to inflate said inner bladder and expand a liner carried by said bladder assembly so that said liner can be brought into firm contact with an interior surface of said pipeline; and 
   a retrieval line for removing said bladder assembly from said pipeline, said retrieval line being coupled to the retrieval end of said inner bladder so that when said bladder assembly is removed from said liner with said inner bladder deflated, said outer bladder separates from said liner and inverts. 
   Preferably, the installation assembly further comprises an inversion element received by the inner bladder and the outer bladder adjacent the installation end. The inner and outer bladders are coupled to a portion of the inversion element. It is also preferred that the installation assembly further comprises an installation cable coupled to the inversion element external to the bladder assembly. The installation cable is used to pull the bladder assembly to a desired location within the pipeline. 
   In a preferred embodiment, the fluid passage is a hose coupled to the retrieval end of the inner bladder and constitutes the retrieval line. It is also preferred that the installation assembly further include an air pump coupled to the hose to inflate and evacuate the inner bladder. 
   According to another aspect of the present invention there is provided a bladder assembly for installing a liner within a pipeline comprising: 
   an elongate bladder defining an internal reservoir and having a leading end and a trailing end; 
   a valve element coupled to said elongate bladder to permit the ingress and degress of fluid into said bladder thereby to inflate and deflate said bladder; and 
   a sleeve generally surrounding said bladder, said sleeve being coupled to said bladder adjacent said leading end. 
   According to yet another aspect of the present invention there is provided a method of installing a liner in a pipeline comprising the steps of: 
   pulling a bladder assembly carrying a wetted liner in one direction into position in said pipeline, said bladder assembly including an inner bladder having an installation end and a retrieval end and an outer bladder surrounding said inner bladder and contacting an inner surface of said liner, said outer bladder having one end coupled to said inner bladder adjacent said installation end and an opposite free end; 
   introducing fluid into said inner bladder to inflate said inner bladder so that said bladder assembly expands to bring said liner into firm contact with an interior surface of said pipeline. 
   maintaining said bladder assembly in an inflated condition for a time period sufficient for said liner to cure; 
   deflating said inner bladder; and 
   retrieving said bladder assembly from said pipeline by pulling said bladder assembly in an opposite direction via said inner bladder so that when said inner bladder moves out of said liner, said outer bladder separates from said liner and inverts. 
   According to yet another aspect of the present invention there is provided a liner for a variable diameter pipeline comprising: 
   an expandable tube formed from a rolled sheet of flexible material and having an overlapping portion therein; and 
   a web secured to said tube to maintain said tube in a rolled condition, said web defining an expandable joint running generally the length of said tube. 
   Preferably, the overlapping portion is sized to cover the web when the tube is in an expanded condition. It is also preferred that the web is formed of expandable material and extends between an edge of the tube and a main portion of the tube to trap the overlapping portion within the tube. According to still yet another aspect of the present invention there is provided an installation assembly for installing a liner at a junction between a main pipe and a lateral pipe, said installation assembly comprising: 
   an inflatable bladder assembly for carrying a liner, said bladder assembly including a main portion and a lateral portion and defining an internal reservoir, said lateral portion including an inner bladder and an outer bladder, said outer bladder extending at least along a portion of the length of said inner bladder, said outer bladder and inner bladder being coupled adjacent a distal end of said lateral portion; and 
   a fluid passage coupled to said bladder assembly to introduce fluid into said internal reservoir and inflate the main and lateral portions of said bladder assembly thereby to expand said liner so that when said lateral portion extends into said lateral pipe and said main portion is in said main pipe, said liner is brought into contact with the interior of said main and lateral pipes and conforms to the shape of said junction. 
   Preferably, the lateral portion of the bladder system includes an inner bladder and an outer bladder. The outer bladder extends at least along a portion of the length of the inner bladder. The outer and inner bladders are coupled adjacent a distal end of the lateral portion. It is also preferred that a carder extends through the main portion of the bladder system. A second installation cable is coupled to a leading edge of the carrier and a retrieval carrier is coupled to a trailing edge of the carrier. It is also preferred that the fluid passage is in the form of a hose having one end received by the carrier. 
   According to still yet another aspect of the present invention there is a method of installing a liner having main and lateral portions at a junction between main and lateral pipes, said method comprising the steps of: 
   pulling a bladder assembly carrying a wetted liner into said pipeline, said bladder assembly including a main portion and a lateral portion and defining an internal reservoir, said bladder assembly being positioned so that the lateral portion thereof extends into said lateral pipe and with the main portion thereof positioned in said main pipe; 
   introducing fluid into said bladder assembly to inflate said bladder assembly so that said bladder assembly expands to bring said liner into firm contact with interior surfaces of the main and lateral pipes and conform said liner to the shape of said junction; 
   maintaining said bladder assembly in an inflated condition for a time period sufficient for said liner to cure; 
   deflating said bladder assembly; and 
   retrieving said bladder assembly from said pipeline by pulling said bladder assembly from said liner. 
   The present invention provides advantages in that liners can be installed in pipelines in a relatively simple manner without requiring excavation to access the pipelines. The present invention also provides advantages in that liners can be installed at junctions between main and lateral pipes in a single application. The present invention provides further advantages in that variable diameter pipelines can be repaired and/or reinforced while ensuring high integrity linings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the present invention will now be described more fully with reference to the accompanying drawings in which: 
       FIG. 1  is side sectional view of an installation assembly for installing a liner within a pipeline in accordance with the present invention; 
       FIG. 2  is a side elevational view, partly in section, of the installation assembly of  FIG. 1  in a deflated condition being inserted into a pipeline and carrying a liner; 
       FIG. 3  is a side sectional view of the installation assembly of  FIG. 1  in an inflated condition to install a liner in a pipeline; 
       FIG. 4  is a side sectional view of the installation assembly of  FIG. 1  in a deflated condition prior to removal from a pipeline; 
       FIG. 5  is a side sectional view of the installation assembly of  FIG. 1  during retrieval from a pipeline; 
       FIG. 6  is a perspective view of a portion of a liner for installation in a variable diameter pipeline in accordance with the present invention; 
       FIG. 7  is a top view of a piece of flexible material forming a tubular portion of the liner of  FIG. 6 ; 
       FIG. 8  is a top view of a web and strips of felt forming part of the liner of  FIG. 6 ; 
       FIG. 9  is a side elevational view, partly in section, of the liner of  FIG. 6  being installed in a variable diameter pipeline using the installation assembly of  FIG. 1 ; 
       FIG. 10  is a side sectional view of the installation assembly of  FIG. 1  in an inflated condition to install the liner of  FIG. 6  in a variable diameter pipeline; 
       FIG. 11  is a cross-sectional view of a portion of the liner of  FIG. 6  expanded within a smaller diameter portion of a variable diameter pipeline; 
       FIG. 12  is a cross-sectional view of another portion of the liner of  FIG. 6  expanded within a larger diameter portion of a variable diameter pipeline; 
       FIG. 13  is a side sectional view of the installation assembly of  FIG. 1  during retrieval from a variable diameter pipeline; 
       FIG. 14  is a side elevational view, partly in section, of an alternative embodiment of an installation assembly for installing a liner at a T-junction within a pipeline in accordance with the present invention; 
       FIG. 15  is a sectional view of a portion of the installation assembly of  FIG. 14 ; 
       FIG. 16  is a perspective view of another portion of the installation assembly of  FIG. 14  with the installation system carrying a liner; 
       FIG. 17  is a side sectional view of a portion of the installation assembly of  FIG. 14  during installation of a liner at a pipeline T-junction; and 
       FIG. 18  is a side sectional view of the installation assembly of  FIG. 14  during retrieval from a pipeline. 
   

   BEST MODES FOR CARRYING OUT THE INVENTION 
   Turning now to  FIG. 1 , an installation assembly for installing a liner within a pipeline in accordance with the present invention is shown and is generally identified by reference numeral  20 . As can be seen, installation assembly  20  includes a double bladder assembly  22  comprising an inner bladder  26  defining an internal reservoir  26   a  and an outer bladder  28  surrounding the inner bladder  26 . The inner bladder  26  is elongate and has a leading installation end  26   b  and a trailing retrieval end  26   c . An inversion element  30  that is generally shaped like an I-section having a pair of blocks  30   a  and  30   b  joined by a bight  30   c , is partially accommodated by the inner bladder  26 . Specifically, the leading installation end  26   b  of the inner bladder  26  receives the block  30   a  and is secured to the bight  30   c  by a clamp  31   a  to seal the leading installation end  26   b  of the inner bladder. The trailing retrieval end  26   c  of the inner bladder accommodates a valve  32  to enable fluid to enter the internal reservoir  26   a  and inflate the inner bladder  26 . 
   The outer bladder  28  surrounds the inner bladder  26  like a sleeve and has a leading end  28   a  that is secured to the bight  30   c  of the inversion element  30  by a second clamp  31   b . Unlike the inner bladder  26 , the trailing end  28   b  of the outer bladder  28  is open. 
   A winch cable  34  is coupled to block  30   b  of the inversion element  30  and is pulled by a winch (not shown). A hose  36  is coupled to the valve  32  and communicates with a fluid source such as an air pump (not shown). 
   Turning now to  FIGS. 2 to 5 , the operation of the installation assembly  20  during installation of a liner within a pipeline will be described. Initially, the double bladder assembly  22  is inserted into a cylindrical tubular liner L that has been impregnated with epoxy. The liner L may be impregnated with epoxy either before or after the double bladder assembly  22  has been inserted into the liner L. The process of impregnating the liner L with epoxy is commonly referred to as “wetting”. 
   After the liner L has been wetted and with the double bladder assembly  22  inserted therein, the winch is operated so that the liner L and double bladder assembly  22  are pulled into the pipeline P to be repaired and/or reinforced via the winch cable  34 , as shown in  FIG. 2 . Once the liner L and double bladder assembly  22  are at the desired location within the pipeline P, the air pump is operated to supply air to the hose  36 . Air fed to the hose  36  passes through the valve  32  and enters the internal reservoir  26   a  of the inner bladder  26  thereby to inflate the inner bladder  26 . The inner bladder  26  is inflated until the double bladder assembly  22  expands to the point where the liner L firmly contacts the interior surface of the pipeline P as shown in  FIG. 3 . The double bladder assembly  22  is then maintained in this condition for a time period sufficient to enable the liner L to cure. 
   Following curing of the liner L, the air pump is operated to evacuate air from the internal reservoir  26   a  of the inner bladder  26  via the valve  32  and hose  36 . As the inner bladder  26  shrinks during evacuation of the internal reservoir  26   a , the outer bladder  28  remains adhered to the liner L, as shown in  FIG. 4 . 
   Once the inner bladder  26  has been deflated, the double bladder assembly  22  is retrieved from the pipeline P. During retrieval of the double bladder assembly  22 , the hose  36  is used to pull the inner bladder  26  back out of the pipeline P. As the inner bladder  26  moves, the outer bladder  28  inverts about inversion element  30  and peels away from the liner L, as shown in  FIG. 5 . This process is continued until the outer bladder  28  has completely separated from the liner L and the inner bladder  26  and inverted outer bladder  28  are removed from the pipeline P. 
   Although the installation assembly  20  has been shown installing a liner L into a pipeline P that has a constant diameter, the installation assembly  20  can also be used to install a liner into a pipeline having a variable diameter. In this case, it is preferred to use a liner particularly adapted for use at junctures between pipelines of differing diameters. 
   Turning now to  FIG. 6 , a pipeline liner for installation in a variable diameter pipeline is shown and is generally identified by reference numeral  40 . As can be seen, the variable diameter pipeline liner  40  includes a generally rectangular piece of flexible material, such as felt, that is rolled up to take the form of a tube  42  with the ends of the material overlapping. A web  44  formed of flexible material runs the length of the tube  42  and extends between the outer edge  42   a  of the tube  42  and the main web  42   b  of the tube to trap an overlapping portion of material  46  within the tube and define on expandable joint. The ends of the web  44  are secured to the tube  42  by strips of felt  48  fused to the side edges of the web  44 . 
   During formation of the liner  40 , a flat stock of material is cut to yield a rectangular piece of material  50  that can be rolled into a tube having a diameter suitable for use in the variable diameter pipeline to be repaired and/or reinforced, as shown in  FIG. 7 . The web  44  having the strips of felt  48  fused to its side edges is also formed as shown in  FIG. 8 . Following this, the piece of rectangular material  50  is rolled into a tube and the strips of felt  48  are fused to the tube  42  to complete the liner  40  as shown in  FIG. 6 . For example, for a pipeline having a transition from a 4 inch diameter to a 6 inch diameter, the rectangular piece of material  50  is rolled up to form a tube  42  having an inner diameter of 3.5 inches. A 3 inch wide piece of expandable material is used as the web  44 . Strips of felt  48 , each having a width of about ¾ inches are used to secure the web  44  to the tube  42 . 
   Turning now to  FIGS. 9 to 13 , installation of the liner  40  into a variable diameter pipeline will be described. With the liner  40  formed in the manner described above, the liner  40  is prepared for installation by inserting the double bladder assembly  22  into the tube  42  and wetting the liner L. The liner  40  is then inserted into the variable diameter pipeline P and is pulled via the winch cable  34  until the liner  40  is positioned at the junction between pipes  52  and  54  of different diameters, such as for example a 4 inch to 6 inch transition. 
   With the liner  40  correctly positioned within the pipeline P, the inner bladder  26  of the double bladder assembly  22  is inflated in the manner described previously. As the inner bladder  26  inflates, the double bladder assembly  22  expands the liner  40  and forces the liner  40  into contact with the interior surfaces of both pipes  52  and  54 . The web  44  of the liner  40  accommodates the different expansion diameters of opposite ends of the liner  40  allowing the liner to form a smooth transition between the different diameter pipes  52  and  54 . 
   During expansion of the liner  40 , the portion of the liner tube  42  within the smaller diameter pipe  52  does not fully expand as shown in  FIG. 11 . As a result, a significant amount of the overlapping portion  46  remains trapped in the tube  42  and overlaps with the interior surface of the main web  42   b . The portion of the liner tube  42  within the larger diameter pipe  54  however, fully expands as shown in  FIG. 12 . In this fully expanded condition, the overlapping portion  46  still overlaps with a small portion of the interior surface of the main web  42   b . In this manner, the overlapping portion  46  always extends across the web  44  so that the thickness of the liner  40  at the location of the web  44  is not compromised. Thus, the liner  40  has at least a minimum thickness corresponding to the thickness of the flexible material  50 , about its entire circumference. 
   With the liner  40  expanded within the pipeline P, the liner  40  is allowed to cure. Since the entire liner  40  is soaked with epoxy, the overlapping portion  46  adheres to the interior surface of main web  42   b . Once the liner  40  has cured, the inner bladder  26  is deflated and the double bladder assembly  22  is retrieved from the pipeline P in the manner previously described as shown in  FIG. 13 . 
   Although the installation of the liner  40  within the variable diameter pipeline has been described with reference to the installation assembly  20  shown in  FIGS. 1 to 5 , those of skill in the art will appreciate that the liner  40  may be installed in variable diameter pipelines using other methods and installation assemblies. 
   Turning now to  FIGS. 14 to 16 , an alternative embodiment of an installation assembly for installing a liner at a T-junction within a pipeline in accordance with the present invention is shown and is generally identified by reference numeral  100 . As can be seen, the installation assembly  100  includes a T-shaped bladder assembly  102  having a main portion  104  and a lateral portion  106  connected by a fused T-joint  108 . 
   The main portion  104  of bladder assembly  102  includes a single bladder  110  defining an internal reservoir  112 . The lateral portion  106  of the bladder assembly  102  includes inner and outer bladders  116  and  118  respectively. The inner bladder  116  also defines an internal reservoir  120  that is in fluid communication with the internal reservoir  112 . The outer bladder  118  is in the form of a sleeve and surrounds the inner bladder  116  partially along its length. 
   An inversion element  130  similar to that described with reference to  FIGS. 1 to 5  is partially received by the distal ends of the inner and outer bladders  116  and  118  respectively. The distal ends of the inner and outer bladders  116  and  118  are secured to the bight  130   a  of the inversion element by clamps  131   a  and  131   b  respectively. An installation cable  134  is coupled to the exterior block  130   b  of the inversion element  130  and extends to a winch (not shown). 
   A transportation device or carrier  140  extends through the bladder  110 . The bladder  110  is sealed to the carrier  140  to allow the bladder  110  to be inflated. An installation cable  142  is attached to the leading end  140   a  of the carrier  140  and extends to a winch (not shown). A retrieval cable  144  is attached to the trailing end  140   b  of the carrier  140  and extends to a winch (not shown). A hose  146  having one end coupled to a fluid source such as an air pump (not shown) extends through the carrier  140  and is in fluid communication with the internal reservoir  112  of the bladder  110  via a valve (not shown). 
   Turning now to  FIGS. 14 to 18 , installation of a liner  150  into a pipeline having a T-junction using the installation assembly  100  will be described. As can be seen in  FIG. 16 , the liner  150  is generally T-shaped and includes a main portion  162  and a lateral portion  154 . Similar to the previous embodiments, the liner  150  is firstly prepared for installation by inserting the bladder assembly  102  into the liner  150  and wetting the liner  150 . During insertion, the main portion  104  of the bladder assembly  102  is pulled through the main portion  152  of the liner  150  and the lateral portion  106  of the bladder assembly  102  is pulled through the lateral portion  154  of the liner  150 . 
   With the liner  150  prepared for installation, the bladder assembly  102  is launched through a manhole  160  and into a main pipe  162 . A remote controlled camera  164  is also placed in the main pipe  162 . The installation cable  134 , which has been previously fed through a lateral pipe  166  that is connected to the main pipe  162  to define the T-junction to be repaired and/or reinforced, is then used to pull the lateral portion  104  of the bladder assembly  102  into the main pipe  162 . Once the full length of the lateral portion  104  of the bladder assembly  102  is in the main pipe  162 , the installation cables  142  and  134  are pulled simultaneously. Pulling of the installation cable  142  advances the carrier  140  and hence bladder assembly  102  towards the T-junction defined by the main and lateral pipes  162  and  166  respectively. Pulling of the installation cable  134  advances the lateral portion  106  of the bladder assembly  102  up into the lateral pipe  166 . During this stage, the remote controlled camera  164  is used by technicians to assist in the proper positioning of the liner  150  at the T-junction as shown in  FIG. 17 . 
   With the liner  150  properly positioned at the T-junction, the air pump is operated to feed air into the hose  146 . Air fed into the hose  146  enters the internal reservoir  112  of the bladder  110 . Since the bladders  110  and  116  are in fluid communication, air entering the internal reservoir  112  also enters the internal reservoir  120 . Air is fed to the bladder assembly  102  until both bladders  110  and  116  are fully inflated so that the liner  150  is expanded and forced into contact with the interior surfaces of the main and lateral pipes  162  and  166  as shown in  FIG. 17 . As in the previous embodiments, the bladder assembly  102  is maintained in this condition until the liner  150  cures. 
   Following curing of the liner  150 , the air pump is operated to evacuate air from the internal reservoirs  112  and  120  of the bladders allowing the bladders  110  and  116  to deflate. The outer bladder  118  however remains adhered to the liner  150 . When the bladders  110  and  116  have been deflated, the retrieval cable  144  is pulled to remove the bladder assembly  102  from the liner  150 . During removal of the bladder assembly  102 , as the carrier  140  and bladder  110  are pulled out from the main portion  152  of the liner  150 , the inner bladder  116  is pulled out of the lateral portion  154  of the liner  150 . As this occurs, the outer bladder  118  inverts about the inversion element  130  and is pulled from the liner  150 . With the outer bladder  118  separated from the liner  150 , the retrieval cable  144  is pulled until the bladder assembly  102  is removed from the pipeline via the manhole  160 . 
   Although the installation system  100  is shown for use in installing a liner at a T-junction between a lateral pipe and a main pipe, those of skill in the art will appreciate that the installation system can be used to install liners in other types of pipe junctions. 
   Also, although preferred embodiments of the present invention have been described, those of skill in the art will appreciate that variations and modifications may be made without departing from the spirit and scope thereof as defined by the appended claims.