Abstract:
The present invention is a new liner assembly for use in pipes constructed from a flexible liner formed from a resin absorbent material. A compressible material, such as stitch-bond or foam, is attached to one or more sides of the liner for forming a taper along the compressible material when the liner is cured in place in the pipe using a curable resin and an expandable bladder to shape the liner to match the inside shape of the pipe. A taper is formed along the compressible material from the inside of the liner down to the inside of the pipe in which the liner is placed. As a result, a taper prevents accumulation of solid materials at the location of the pipe repair and thus prevents future clogging of the pipe at the repair.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to pipe repair. Specifically, the present invention relates to a new method and device for lining pipe. 
         [0002]    A system which is commonly used for repairing damaged sewer pipes is called cured-in-place pipe repair. Cured-in-place pipe repair is typically a fabric felt-type liner, impregnated with a liquid resin, formed inside an existing conduit or pipe and cured or hardened to become a one-piece continuous new pipe lining. The liner is pressed outward against the pipe using an expandable bladder. The resin cures, forming the liner tightly along the inside of the pipe in the damaged area, thereby creating a water tight seal and repairing the pipe. 
         [0003]    Cured-in-place technology is used to renew main sewer pipes, lateral sewer pipes as well as other types of conduits. When using cured-in-place pipe repair for renewing both main and lateral pipes, the lining is generally either pulled in place and inflated or inverted into place and inflated. One problem, however, with this type of pipe repair is that the edges of the liner create ridges inside the pipe where solids can collect and create blockage inside the pipe. This is particularly problematic on the edge at the upstream end of the liner. 
         [0004]    In general, when a section of cured-in-place pipe, whether straight, curved, or pipe junction, is placed in a sewer pipe, the edge of the liner is raised by the thickness of the liner and thus creates an area for buildup of solids, thereby blocking the pipe. Thus, it is desirable to have an improvement in cure-in-place pipe liners. 
         [0005]    When these liners are pulled into place or inverted into place the liner is generally attached to the bladder in some manner to get the liner into proper position inside the damaged pipe. Then, once the resin cures, the bladder is removed. However, to remove the bladder, the connection between the bladder and the liner must be frangible. Therefore, connections between the bladder and the liner have used connecting strips stitched to the bladder and held to the liner with an adhesive or other means which can be broken. Stitching the fabric liner directly to the bladder puts unwanted holes in the liner which may leak at the damaged portion of the pipe once the stitches are removed or broken and dissolved. Another problem with these and other known frangible connections between the bladder and the liner is that the frangible connection is difficult to break once the liner resin cures in place inside the pipe. Therefore an improved frangible connection between the bladder and the liner is desirable. 
         [0006]    In light of the foregoing, the primary feature and advantage of the present invention is to provide an improved new method and device for lining pipe. 
         [0007]    A further feature or advantage of the present invention is a device for lining pipe which reduces solids accumulation and thus reduces chance for blockage of pipe repairs. 
         [0008]    A further feature or advantage of the present invention is a method of lining pipe which reduces blockage in the pipe being repaired. 
         [0009]    Another feature or advantage of the present invention is a method of frangibly connecting a liner tube to an elongated positioning tube or an inversion bladder where the frangible attachment is strong during placement of the liner, yet can be easily broken or separated during removal of the positioning tube or bladder once the liner resin has cured. 
         [0010]    Yet another feature or advantage of the present invention is a device for frangibly connecting a pipe repair liner to an expansion bladder which is strong during placement of the liner yet can be easily broken or disconnected during removal of the positioning hose or bladder once the liner resin has cured. 
         [0011]    A further feature or advantage of the present invention is a device for lining pipe which is economical to manufacture, durable in use and efficient in operation. 
         [0012]    One or more of these and/or other features or advantages of the present invention will be apparent from the specification and claims that follow. 
       BRIEF SUMMARY OF THE INVENTION 
       [0013]    The present invention is an improved method and device for lining pipe where a resin impregnated material is placed inside a pipe and expanded using an inflated bladder wherein the resin is allowed to cure. At least a portion of an end of the liner has a transition collar forming a taper from the inside surface of the pipe to the inside surface of the liner when the liner is cured in place in the pipe to allow solids to pass over the taper thus reducing chances of accumulation of solids in the repaired pipe. 
         [0014]    The transition collar is preferably more compressible than the liner. In addition, the transition collar preferably has a coating which can be frangibly connected to the expandable bladder and peeled away from the collar once the liner and collar is cured in place, allowing easy removal of the bladder after curing of the resin. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a pictorial prior art cut away view representation illustrating a cleanout pipe where a cured in-place liner closes off service from the house. 
           [0016]      FIG. 2  is an isometric view of a prior art liner assembly capable of being used at a pipe junction between two sewer lines. 
           [0017]      FIG. 3  is a prior art cutaway view of a partial liner before being inverted into a sewer line. 
           [0018]      FIG. 4  is a prior art cutaway view of a liner inserted into a main sewer line after inversion. 
           [0019]      FIG. 5  is an isometric view of one embodiment of a sheet pipe junction liner assembly incorporating the present invention for lining pipe. 
           [0020]      FIG. 6  is a view of the liner device of  FIG. 5  where the sheet liner forms a tube. 
           [0021]      FIG. 7  is a cut-away view of the sheet liner assembly of  FIG. 5  formed inside a pipe junction of sewer lines. 
           [0022]      FIG. 8  is an enlarged view of a portion of  FIG. 7 . 
           [0023]      FIG. 9  is an end view of  FIG. 7 . 
           [0024]      FIG. 10  is a cutaway view of one embodiment of a partial liner of the present invention before being inserted into a sewer line. 
           [0025]      FIG. 11  is a cutaway view of one embodiment of the present invention inverted into a main sewer line. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    Typical prior art pipe repairs are shown in  FIGS. 1-4 .  FIG. 1  shows a continuous liner tube  32  from the insertion point of the access or cleanout pipe  18  through the lateral pipe  12  to the main sewer pipe  10 .  FIG. 2  shows a liner assembly used for repairing pipe junctions such as at a main sewer line  10 /lateral sewer line  12  junction or at a lateral sewer line  12 /cleanout  18  junction.  FIG. 3  shows one method for inserting a tube liner  32  into a partial section of lateral line  12  using an air pressure driven inversion process. Other types of positioning devices (not shown) can also be used to locate the liner  30  inside the pipe  10 ,  12  as would readily be understood by those skilled in the art.  FIG. 4  shows a tube liner  32  curing in place to repair a partial section of a lateral line  12 . 
         [0027]    The liner  32  may or may not have an outer polymer-type coating  31 . If the liner  32  has an outer coating  31  and the liner  32  is pulled into place, the resin impregnated into the lining  32  will remain contained within the coated tube, preventing resin from migrating into pipe brakes and open joints. If the lining  32  does not have an outer coating  31  and the liner  32  is pulled into place, the resin impregnated into the lining  32  may be contaminated and even wiped off during the pulling-in process. Thus, the inversion procedure is generally preferred for eliminating these issues. 
         [0028]    In  FIG. 1 , a main sewer line  10  is connected to a lateral sewer line  12  inside manhole  14 . Generally, an access pipe/cleanout  18  allows access to the lateral sewer line  12  and the main sewer line  10  without having to dig up the earth or compromise the sewer lines  10 ,  12 . The lateral sewer line  12  extends to a house  20  giving access to the main sewer line from the house  20 . 
         [0029]    A pulled-in place liner requires two access points. One access point is a manhole  14 , which is commonly located in public streets. The other access point may be another manhole  16 , as shown in  FIGS. 4 and 11 , or it can also be a clean-out pipe  18 . Then, the liner  32  is pulled from one access point toward the second access point using a rope or other means until the liner is properly positioned in the damaged pipe. 
         [0030]    The inversion method requires only one access point. It is generally considered a superior method for inverting a liner  32 , allowing the liner  32  to be inserted into the pipe from only one access point, and allowing resin to contact the pipe directly and migrate into broken areas of the pipe without damaging the liner. However, inverting a full continuous liner  32  through a clean-out pipe  18  and into the lateral line  12  creates an upstream side which blocks off service from the house  20  through the main sewer line  10 , as shown in  FIG. 1 . This is because the liner is within both the clean-out pipe  18  and the lateral pipe  12 , blocking out the lateral pipe  12  at  38 . Therefore, the lining  32  will need to be cut out at  38  after the resin is cured to reinstate service to the house  20 . This type of reinstating process requires expensive equipment, additional time, and if the cut is not smooth, solids will build up on a ridge at  39  created by the lining, causing backups within the pipe. 
         [0031]    The repair in  FIG. 1  shows a prior art bladder/liner assembly having a bladder tube  24 , an open end or upper end of the bladder tube  26 , and a closed end or lower end of the bladder tube  28 . A pull line  30  is attached to the closed end  28  of the bladder tube  24  for use in removing the bladder tube  24  once the resin has cured.  FIG. 3  shows that a liner tube  32  is inserted into a bladder tube  24  before inversion. Also, the liner tube  32  may have a polymer or other type of coating  31 . The liner tube  32  is then positioned on the exterior of the bladder tube  24  after inversion. As can be seen from the figure, the liner tube  32  includes an access portion  34  of the liner tube  32  within the access pipe  18  and a lateral portion  36  of the liner tube  32  within the lateral line pipe  12 . 
         [0032]    Another prior art liner assembly  40  is shown in  FIG. 2 . This type of liner assembly  40  is used at T-type junctions to repair the junction or the pipe near the junction. The liner assembly  40  includes a tubular lateral liner  42  connected to a flat sheet liner  48  that rolls around onto itself forming a tube prior to installation. Both liners  42  and  48  are generally formed of felt or other resin absorbent material. Lateral liner  42  is formed by connected side edges of a sheet of liner material with a polymer coating  44  on one side, such that the polymer coating  44  is on the exterior of the tube being formed. The edges of the sheet are sewn together at a seam  52 , and a strip of polymer tape  54  is welded over the seams  52  to form an airtight and water tight seal. 
         [0033]    The flat sheet liner  48  has a central opening formed therein, and has a polymer coating  50  on the top surface thereof. The lateral liner tube  42  is preferably sewn to the flat sheet liner  48  around the opening, and a strip of polymer tape  54  is then welded continuously around the juncture to form an airtight and water tight seal. 
         [0034]    Once liner assembly  40  has been completed, the liner  40  is moved into place in the sewer line  10 ,  12 ,  18  by any method which works to properly locate the liner assembly  40  inside the pipe junction. 
         [0035]    A quantity of curable liquid resin is introduced onto the liner assembly  40  and covers the liner assembly  40  and completely impregnates the liner assembly  40 . A bladder tube similar to that shown as  24  in other figures is inserted into the liner assembly  40  and expanded while the resin is allowed to cure. Thus, the liner assembly  40  takes the shape of the pipe  10 ,  12 ,  18  to fix or cover the junction or any damaged areas. However, as mentioned above, the edges on the liner assembly  40  can create ridges inside the pipe, shown at  39  in  FIGS. 1 and 4 , thereby causing a blockage or an area for solids to gather and create a blockage in the pipe  10 ,  12 ,  18 . 
         [0036]      FIGS. 3 and 4  show prior art examples of inverting a liner tube  32  into a pipe  10 ,  12 ,  18 . One having ordinary skill in the art would understand how the inversion process works to insert a liner tube  32  into a pipe  10 ,  12 ,  18 . An external launcher  70  (shown as partial) is utilized outside the access pipe/clean out  18 . The external launcher  70  has a launcher chamber  71  and a launcher opening  72 . Air pressure, shown as arrows  73 , is injected into the launcher chamber  71  for causing an inversion of the bladder tube  24  and the liner tube  32 . A guide tool assembly  76  may be used to help direct the bladder tube  24  and the liner tube  32  to travel in the proper direction. 
         [0037]    Using the inversion method of insertion of the liner, preferably the liner has a thin coating  31  on the outside of the liner  32 ,  40  which contacts the inside of the bladder tube  24  when the liner  32 ,  40  is located inside the bladder tube  24  for inversion.  FIGS. 3 and 4  show that the liner tube may be frangibly attached at  33  to the bladder tube  24  to allow the liner tube  32  to travel with the bladder tube  24  to the desired location. The frangible attachment or connection  33  may be frangibly connected to a bladder  24  by stitches, a solvent weld, or other method. A disadvantage to stitches is the connection points are at various specific points around the circumference of the liner  32  which does not provide uniform pull on the beginning of the liner. Further, the stitches are the same strength during inversion as they are when the bladder  24  is removed. This is because the liner  32  is not actually stitched to the bladder  24  because the bladder  24  cannot be punctured from stitches. Therefore, the bladder  24  has either a connecting collar (not shown) or connecting strips (not shown) attached at the beginning of the liner  32 . 
         [0038]    The inversion process inverts the bladder  24  and the liner  32 ,  40  inside the pipe  10 ,  12 ,  18 . Thus, the outside or the polymer coating  31 ,  44 ,  50  before the inversion becomes the inside of the liner  32 ,  40  after inversion. This is best shown in  FIGS. 3 and 4 . The bladder  24  is inflated so the liner  32 ,  40  is pressed against the inside of the pipe  10 ,  12 ,  18  during curing of the resin. The pull line  30  is then pulled after the resin cures to break the frangible connection  33  and remove the bladder  24 . However, as seen at  39  in  FIG. 4 , ridges are formed by the thickness of the bladder  32 ,  40 . 
         [0039]      FIGS. 5-9  show one embodiment of the new liner assembly  60  of the present invention for use in pipe junctions in pipes. The liner assembly  60  is constructed from a flat sheet liner  48 . The liner assembly  60  may have a tubular lateral liner  42  attached to an opening in the flat sheet liner  48  for allowing the liner assembly  60  to be used where a lateral sewer line  12  connects with a main sewer line  10  or where a cleanout  18  connects with a lateral sewer liner  12 . Preferably the lateral liner  42  has a thin polymer coating  44  and the flat sheet liner  48  has a thin polymer coating  50 . The liner assembly  60  may be formed without a tubular lateral liner  42  from a flat sheet liner  48  for repairing straight pipes. In other words, the present invention can be incorporated with an end of a lateral lining  42  that is connected to an opening in a flat sheet liner  48  for repairing pipe junctions, or the flat sheet liner  48  can be wrapped around itself forming a tube without a lateral liner  42  for repairing straight pipe. Also, as described below, a continuous liner tube  32  can be formed as a tube for repairing pipes. 
         [0040]    Attached to any tubular lateral liner  42  and/or one or more edges of the flat sheet liner  48  is a transition collar made from a compressible material  62 . The compressible material  62  is stitched or otherwise securely held to the tubular lateral liner  42  and/or the flat sheet liner  48 . The compressible material  62  can be constructed from stitch-bond material, foam, or any other easily compressible material capable of being impregnated with a resin. Preferably the compressible material  62  has a thin polymer coating  63 . The transition collar extends away from at least a portion of the liner  32 ,  42 ,  48  to provide a taper  64  from the inside surface of the pipe to the inside surface of the liner  32 ,  42 ,  48  when the resin cures the liner in place. With the taper  64 , instead of a ridge  39 , solids are less likely to accumulate inside the pipe at the repair. 
         [0041]    The flat sheet liner  48  is designed to fold around onto itself, creating a tube which fits within the pipe  10 ,  12 ,  18  which is to be repaired. This is best shown in  FIG. 6 . Any process or system (such as pulled into place or inversion processes described above) can be used for inserting the liner assembly  60  into the pipe  10 ,  12 ,  18  which is to be repaired. Holes  66  may be included in the liner assembly  60  to help an installer install the liner  60  into the pipe  10 ,  12   18  using the pulled into place method. 
         [0042]    The liner assembly  60  is cured in place in the pipe  10 ,  12 ,  18  using a curable resin which cures while a bladder tube  24  is expanded inside the liner assembly  60  in the pipe  10 ,  12 ,  18 . Once the resin cures, the bladder tube  24  can be removed leaving the liner assembly  60  formed in the shape of the inside of the pipe  10 ,  12 ,  18 . 
         [0043]    Since the transition collar or compressible material  62  is easily compressible, the compressible material  62  is cured in the shape of a taper  64  from the inside of the liner  60  down to the inside edge of the pipe  10 ,  12 ,  18 . This taper  64  acts as a ramp allowing solids to pass right through the liner  60  without getting hung up on edges or ridges  39 . Thereby, the present invention pipe lining is much less prone to creating a future blockage within the pipe  10 ,  12 ,  18 . 
         [0044]      FIGS. 10 and 11  show an embodiment of the present invention using a tubular liner  32  for lining straight pipe sections using an inversion process for installing the bladder  32  inside a pipe  10 ,  12 ,  18  as described above. Similar to the new liner assembly  60 , the tube liner  32  of the present invention has transition collar or compressible material  62  attached to edges or ends of the tube liner  32 . Here again, the compressible material  62  on the liner tube  32  forms a taper  64  for reducing chances of buildup or blockage inside the pipes  10 ,  12 ,  18 . 
         [0045]    Preferably the compressible material  62  has a thin polymer or other type of coating  63  of polyurethane, polyvinyl chloride, or the like. A frangible attachment  65  may be used to hold the liner tube  32  to the bladder tube  24 . The frangible attachment  65  can be accomplished with a solvent that chemically bonds the coating on the compressible material  63  to the bladder  24 . It is preferred that the coating  63  on these short sections of compressible material  62  be used to make the frangible connection  65  by solvent welding the coating  63  to the bladder  24 . The frangible attachment  65  allows the bladder  24  to pull the liner  32  into place in the pipe  10 ,  12 ,  18  as the bladder  24  is inverted into the pipe. Then, the coating  63  can break away from the compressible material  62  when the bladder  24  is removed after the resin cures. This works very well because essentially the entire  360  degrees of the compressible material  62  (via the coating  63 ) is bonded to the bladder  24 . When the liner  32  is being inverted into the pipe, the pull inverting the liner  32  is a straight flat pull so the connection between the bladder  24  and the compressible material  62  via the coating  63  is strong. This is like pulling a banana peel straight, not peeling it. It is very difficult to pull apart. However, when the bladder  24  is removed via the pull line  30 . The bladder  24  is re-inverted out of the pipe  10 ,  12 ,  18  causing the bladder  24  to be peeled away from the liner  32  and the thin coating  63  is easily peeled off and away from the compressible material  62 . This is like peeling the banana peel and the coating  63  easily peels away from the compressible material  62  as the bladder  24  is removed. 
         [0046]    The liner of the present invention can be a tubular liner, such as a tube sock, or can form a tube from a flat sheet, such as  48 . In addition, the liner does not need to form a tube and can simply cover a portion of the inner circumference of the pipe. Furthermore, the transition collar or compressible material  62  does not need to extend around the entire circumference of the pipe. 
         [0047]    As mentioned above, any system or method for getting the new liner assembly  32 ,  60  into place within the pipe  10 ,  12 ,  18  and curing the liner assembly  32 ,  60  in place can be used. For example, but not limited to, the systems and methods used in U. S. Pat. Nos. 5,855,729; 5,964,249; and 6,039,079 to the inventor of the present invention, and U.S. application Ser. No. 11/359,026, also to the inventor of the present application, can all be used and are herein incorporated by reference in their entirety. 
         [0048]    The invention has been shown and described above with the preferred embodiments, and it is understood that many modifications, substitutions, and additions may be made which are within the intended spirit and scope of the invention. From the foregoing, it can be seen that the present invention accomplishes at least all of its stated objectives.