Abstract:
An apparatus for replacing an existing pipe. The apparatus comprises a slitter and expander which surround a wire rope. The wire rope is attached to the expander, and the expander abuts either the slitter or a separation tube disposed between the expander and slitter, such that the slitter and expander are pivotable relative to each other. The apparatus is placed in a pipe to be replaced and pulled. While being pulled, blades on the slitter slit the pipe, while a sloped surface of the expander moves the slit sections apart into surrounding soil. A replacement pipe may be pulled by a pipe putter attached to the expander. A beacon may also be disposed within the apparatus to emit a signal for locating the apparatus white underground.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 14/509,859, filed Oct. 8, 2014, which claims the benefit of provisional patent application Ser. No. 61/888,061 filed on Oct. 8, 2013, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present invention relates generally to the field of replacing existing utility lines, such as gas and water lines, through splitting and installing lines in the subsurface. 
       SUMMARY 
       [0003]    The present invention is directed to an apparatus for expanding and replacing a pipe, The apparatus comprises a slitter, an expander, a beacon and a wire rope. The slitter comprises a tapered section having a first end and a second end, wherein the cross-sectional area of the first end is less than the cross-sectional area of the second end. The beacon assembly is disposed proximate the expander and generates a magnetic field. 
         [0004]    In another embodiment the present invention is directed to a method for replacing an existing pipe. The method comprises placing a wire rope through the existing pipe, disposing a slitter about the wire rope at a first end of the existing pipe, disposing an expander about the wire rope at a first end of the existing pipe, the expander comprising a tapered section and a gripper, attaching the wire rope to the expander by moving the gripper to a gripping position, attaching a beacon to the expander, pulling the wire rope, slitter, expander, and beacon through the existing pipe from the first end to a second end, slitting the existing pipe with the slitter as the wire rope is pulled, emitting a magnetic field from the beacon, and expanding the slit existing pipe with the expander as the wire rope is pulled. 
       BACKGROUND 
       [0005]    Pipe slitting is a process where an existing buried pipeline is separated longitudinally, expanded open circumferentially along with the surrounding soil and a new pipe is pulled in simultaneously as the slitting and expanding process is performed. Variations on the process include removal of the existing pipe prior to installation of the new (product) pipe; however most projects are performed with the slit host pipe remaining in the bore adjacent the product pipe. 
         [0006]    A tensile structure such as a wire rope is pushed or fished through the host pipe and tooling capable of performing the combined slitting/pipe pulling process is attached to one end of the tensile pulling strand. A device capable of applying tension to the strand such as a hydraulic puller or even excavating equipment is coupled to the opposite end. A load is applied and the tooling is pulled along the path of the host pipe, through the ground. 
         [0007]    There remains a need for quick attachment and removal mechanisms that satisfy the desire for an unobtrusive feature somewhere along the length of the tooling. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a side view of the pipe slitter and puller with a centered section line A-A 
           [0009]      FIG. 2  is a pipe slitter and puller shown passing through a curving path of a host pipe. 
           [0010]      FIG. 3  is section A-A of  FIG. 1  showing clamping of the device to a wire rope 
           [0011]      FIG. 4  is a side view of the pipe slitter and puller surrounding a wire rope in a disassembled condition and section line B-B along the centerline. 
           [0012]      FIG. 5  is section B-B shown with the pipe slitter decoupled from a wire rope. 
           [0013]      FIG. 6  is a top view of an alternative pipe slitter and puller. 
           [0014]      FIG. 7  is section C-C of the pilot section of the alternative pipe slitter of  FIG. 6 . 
           [0015]      FIG. 8  is section C-C of the slitter section of the alternative pipe slitter of  FIG. 6 . 
           [0016]      FIG. 9  is section C-C of the separation tube section of the alternative pipe slitter of  FIG. 6 . 
           [0017]      FIG. 10  is a perspective view of the alternative pipe slitter of  FIG. 6  pulling a product pipe. 
           [0018]      FIG. 11  is a diagrammatic representation of a support frame used when pulling a pipe slitter. The pipe slitter shown in  FIG. 11  is an alternative embodiment of the invention. 
           [0019]      FIG. 12  is a top view of the pipe slitter shown in  FIG. 11   
           [0020]      FIG. 13  is section D-D of the beacon assembly of the pipe slitter of  FIG. 12 . 
           [0021]      FIG. 14  is a perspective view of a capstan winch for use with the support frame of  FIG. 11 . 
       
    
    
     DESCRIPTION 
       [0022]    With reference now to the Figures in general and  FIG. 1  in particular, shown therein is an apparatus for replacing a pipe, herein described as a pipe expander assembly  10 . The pipe expander assembly  10  is attached at a first end to a pipe puller  12  by a connector  14 . As shown, the connector  14  is a bolt. Other connectors  14  are considered, and one of ordinary skill in the art could additionally consider making the pipe puller  12  integral with the pipe expander  10 . The pipe expander assembly  10  is attached at a second end to a tensile pulling member, or wire rope  16 . The wire rope  16  is attached at a first end to the pipe expander assembly  10  and at a second end to a pulling member  206  ( FIG. 11 ) such as a cable winch. The pipe expander assembly  10  comprises a slitter  18  and an expander  20 . The slitter  18  comprises at least one blade  22 . As shown, the slitter  18  comprises four blades  22 . Each blade  22  comprises a honed edge  23  for slitting of a host pipe (not shown). The slitter  18  is positioned ahead of the expander  20  and is configured such that when placed within the host pipe, at least one blade  22  of the slitter will slit the host pipe wall. The blades  22  may run the length of the slitter  18 , or only a portion of the length of the slitter as shown in  FIG. 1 . 
         [0023]    Expander  20  comprises a tapered, or frusto-conical section  24 , a jam nut  60 , and a clevis  25 . The frusto-conical section  24  increases in cross-sectional area from front  26  to back  28 . The back  28  of the frusto-conical section  24  is preferably of greater cross-sectional area than the cross-sectional area of the host pipe, such that the host pipe and surrounding soil are expanded by pulling the expander assembly  10  through. The clevis  25  is attached to the pipe puller  12  by the connector  14 , which as shown is a threaded bolt  14 . The clevis  25  may rotate relative to the conic section  24  of the expander  20 . The jam nut  60  is rotationally connected to the clevis  25  and may be threaded into the conic section  24  as will be described in greater detail with reference to  FIGS. 3-5 . 
         [0024]    The pipe puller  12  comprises a tapered section  30  to reduce friction associated with pulling a trailing product pipe in a bore. The pipe putter  12  further comprises an eyelet  32  which allows connection to a tensile string (not shown) and a towing eye  34  for connection to the connector  14  and the expander  20 . One of skill in the art will appreciate that the tensile string allows compression of the product pipe through its length by tensioning the string between eyelet  32  and the trailing end of the product pipe, aiding in prevention of a tensile fracture in the product pipe. 
         [0025]    As shown in  FIG. 2 , the slitter  18  and expander  20  may pivot relative to one another about a spherical joint  70 , as host pipes may not always be straight. The slitter  18  is free to deflect angularly from the expander  20  and follow the path of a host pipe. The deflection between the slitter  18  and the expander  20  is effected by seating the slitter about the wire rope  16  without direct attachment to the wire rope or the expander  20 . The expander  20  is internally attached to the wire rope  16  as will be described in further detail with reference to  FIG. 3 . In this way, the slitter  18  and expander  20  follow the path of the wire rope  16  without direct attachment between the two. This spherical joint  70  is shown in more detail in  FIG. 3 . 
         [0026]    With reference now to  FIG. 3 , shown therein is section A-A of  FIG. 1 . The pipe puller  12  further comprises a body  40 , a sleeve  42 , a set of puller jaws  44 , a cone  46 , an annulus  48  defined by the space between the jaws and the sleeve, and a rod  50 . The rod  50  is mixedly attached to the eyelet  32  on a first end and the towing eye  34  on a second end. The rod  50  travels through the body  40  and is threadedly attached to the cone  46 . The puller jaws  44  are disposed about the rod  50  within the annulus  48 . As the cone  46  is moved along the rod  50  toward the second end of the rod, the puller jaws  44  expand outward within the annulus  48  toward the sleeve  42 . Thus, rotation of the rod  50  while the cone  46  is rotationally fixed to the puller jaws  44  will cause the jaws to expand or contract, depending on the direction of thread and rotation. Further, pulling the rod  50  toward the expander  20  will similarly cause the puller jaws  44  to expand toward the sleeve  42 . 
         [0027]    Product pipe is attached to the pipe puller  12  by placing a product pipe within the annulus  48  and expanding the puller jaws  44  through use of the rod  50  as described above. Clamping force between the puller jaws  44  and sleeve  42  may hold the product pipe in place. As discussed above, a tensile force may be provided to a terminal end of the pipe through connection to a tensile member, such as a wire rope, at the eyelet  32 . Alternatively, an adaptor (not shown) may be used to connect the pipe puller  12  to the product pipe, or the product pipe may be fused to the pipe puller  12 . 
         [0028]    The expander  20  comprises a jam nut  60 , a swivel bolt  62 , a gripper, or expander jaws  64 , and a spring  66 . The swivel bolt  62  allows the clevis  25  to rotate relative to the jam nut  60  and conic section  24 . Therefore, relative rotation between the product pipe (and therefore pipe puller  12 ) and wire rope  16  is accommodated. The expander jaws  64  are disposed inside the conic section  24  about the wire rope  16  and movable between a first position and a second position. In the first position, as shown in  FIG. 3 , the expander jaws  64  are engaged with the wire rope  16  such that the wire rope is connected to the expander jaws and the expander  20 . In the second position, shown in more detail with reference to  FIG. 5  below, the expander jaws  64  do not engage the wire rope  16 , allowing the expander  20  to slide relative to the wire rope. The interior of the conic section  24  comprises threads  67  that mate with lands  68  on the exterior of the jam nut  60 . Alternatively, jam nut  60  and the conic section  24  may connect through a bolted, fused, quick-attach or other known connection method. 
         [0029]    As the jam nut  60  is threaded to the conic section  24 , the expander jaws  64  are forced to grip the wire rope  16  and thus moved from the second position to the first position. The action of tightening jam nut  60  couples the expander assembly  20  to the wire rope  16 . The spring  66  is disposed within jam nut  60  and places a load on expander jaws  64  to keep expander jaws confined within the interior of the conic section  24 . 
         [0030]    As shown, the slitter  18  comprises a channel  72  for the wire rope  16  to pass within. Preferably, the channel  72  is sized to the wire rope  16  such that movement of the slitter  18  relative to the wire rope  16  is limited. The slitter  18  is not directly attached to the wire rope  16 , but is forced forward by the expander  20  at the spherical joint  70  when the wire rope pulls on the expander at the expander jaws  64 . Thus, the slitter  18  has 360 degrees of angular deflection about the spherical joint  70 . 
         [0031]      FIG. 4  is a side view of the pipe expander assembly  10  of  FIGS. 1-3  with the pipe puller removed. In  FIG. 4 , the jam nut  60  has been backed out of section  24 , revealing the lands  68  and placing the expander jaws  64  ( FIG. 5 ) in the second position. Attachment of the expander  20  to the wire rope  16  can thus be illustrated. The expander  20  comprises wrench flats  82  on the back  28  of the conic section  24  and jam nut  60  fiats  84  are used to tighten or loosen jam nut into or out of the conic section  24 . To assemble shown components, first the slitter  18  is piloted over the wire rope  16  and slipped forward. Then expander assembly  20 , with the jam nut  60  threaded out as shown is placed over the end of wire rope  16  with the expander jaws  64  ( FIG. 5 ) in the second position. 
         [0032]    With reference now to  FIG. 5 , the expander jaws  64  comprise a gripping surface  86  for biting into surface of the wire rope  16 . The gripping surface  86  may comprise serrations, teeth, or other known grippers. The gripping surface  86  engages with the wire rope  16  when the jam nut  60  is engaged such that the expander jaws are in the first position due to a reduction of the space disposed within the gripping surface. Conversely, as shown in  FIG. 5 , the gripping surface  86  will not bite into the surface of wire rope  16  when the jam nut is not engaged and the expander jaws  64  are in the second position. Therefore when the jaws  64  are in the second position, slitter assembly  18  and expander  20  will be free to slide off of wire rope  16 . 
         [0033]    In operation, the wire rope  16  is disposed through the existing pipe (not shown). The slitter  18  is placed onto the wire rope, followed by the conic section  24  of the expander  20 . The expander jaws  64  are then moved from the second position to the first position by threading of the jam nut  60  into the conic section  24 . The pipe puller  12  is attached to connector  14 . A new pipe is optionally placed within the pipe puller as described above, if replacement of the existing pipe is desired. The wire rope  16  is then pulled through the existing pipe, causing the blades  22  of the slitter  18  to slit the pipe, the conic section  24  of the expander  20  to expand the pipe, and the new pipe to be pulled into place along substantially the same path as the existing, slit pipe. The new pipe is then disconnected from the pipe puller  12  when the wire rope is pulled all the way through the existing pipe. 
         [0034]    With reference now to  FIG. 6 , an alternative embodiment of a pipe expander assembly  100  is shown. In  FIG. 6 , the pipe expander assembly  100  comprises a pilot  110 , a slitter  112 , a separation tube  114 , an expander  116  and a pipe puller  118 . The pilot  110  surrounds wire rope  16  and guides the expander assembly  100  into a host pipe  120 . The slitter  112  comprises blades  122  similar to slitter  18  of the previous embodiment. As shown, four blades  122  are displaced rotationally in 90 degree increments. 
         [0035]    The separation tube  114  provides distance between the slitter  112  and the expander  116  for optimal pipe expansion. The separation tube  114  may be flexible, and may be of a length chosen for optimal distance between the expander  116  and the slitter  112  for a particular pipe expansion application. Expander  116  and pipe puller  118  perform the same task as expander  20  and pipe puller  12  with reference to  FIG. 1 . Pipe puller  118  is shown with trailing product pipe  121  attached as described with reference to  FIG. 3 . 
         [0036]    While  FIG. 6  shows separation between each of the pilot  110 , slitter  112 , separation member  114 , and expander  116 , it should be appreciated that interaction between these members and the host pipe  120  will cause each member to abut the adjacent member as the pilot, slitter and separation member are forced towards the expander. 
         [0037]    With reference now to  FIG. 7 , section C-C of pilot  110  is shown therein surrounding wire rope  16 . The pilot comprises a central bore  130 , a counterbore  132  and a tapered nose  134 . The tapered nose  134  reduces the likelihood of the pilot to hang on obstructions internal within a host pipe  120  ( FIG. 6 ). Preferably, a maximum outside diameter of the pilot is 75% to 99.9% of an inside diameter of the host pipe. The counterbore  132  allows the tapered nose  142  ( FIG. 8 ) of the slitter  112  to fit partially within the pilot  110 . 
         [0038]    With reference to  FIG. 8 , slitter  112  is shown therein surrounding wire rope  16  along section C-C of  FIG. 6 . The slitter  112  comprises a spherical socket  140  and a nose  142 . The nose  142  fits within the counterbore  132  of the pilot  110 . The spherical socket  140  allows the separation tube  114  ( FIG. 6 ) to abut the slitter  112 . The slitter  112  is substantially similar to the slitter  18  of  FIG. 1 , having the wire rope  16  passing through internal passage  144  and blades  12  to slit the host pipe  120  ( FIG. 6 ). 
         [0039]    With reference now to  FIG. 9 , separation tube  114  is shown therein surrounding wire rope  16  along section C-C of  FIG. 6 . The separation tube comprises an internal passageway  146 , a tapered nose  147 , and a spherical socket  148 . The tapered nose  147  is adapted to abut the spherical socket  140  of slitter  112  ( FIG. 8 ), while the spherical socket  148  of the separation tube  114  abuts a spherical nose of the expander  116  ( FIG. 6 ). In this way, the pilot tube  110 , slitter  112 , separation tube  114  and expander  116  each have two axes of pivotal movement related to any adjacent component. The separation tube  114  may be of any length or diameter appropriate for providing separation between the slitter  112  and the expander  116 . Separation may be desired between the slitter  112  and expander  116  when the profile of the slit pipe (not shown) is curved away from the pipe expander assembly  100  immediately after slitting, but curves back in some distance later. Providing the separation tube  114  enables this distance to be modified based on pipe  120  characteristics and soil conditions. 
         [0040]    With reference now to  FIG. 10 , the pipe expander assembly  100  is shown having a curved disposition as if being pulled through a curved host pipe (not shown) having an axis represented by line  150 . Such curved orientation is made possible by spherical joints between each component of the pipe expander assembly  100  forward of the expander  116  and clevis joint  152 . As shown, the connection between the expander  116  and pipe puller  118  is a clevis joint  152 . Trailing product pipe  121  is thus installed along a path approximating line  150 . 
         [0041]    With reference now to  FIG. 11 , a support assembly  200  for operating a pipe expander assembly  198  is shown. One of ordinary skill can appreciate that the pipe expander assemblies  10 ,  100  of the previous figures may also be utilized with the support assembly  200 . The support assembly  200  comprises a mast  202 , sheave  204 , and winch assembly  206  supported on a trailer  208 . The mast  202  passes the wire rope  16  from the winch assembly  206  to the sheave  204 . The sheave  204  redirects the wire rope  16  into the host pipe  120 . The pipe expander assembly  198  is by the wire rope  16  through the host pipe  120  by the winch assembly  206 . The trailer  208  allows the winch assembly  206  and other portions of the support assembly  200  to be transported to and from a job site. The winch assembly  206  will be shown in more detail with reference to  FIG. 14  below. 
         [0042]    With reference now to  FIG. 12 , the pipe expander assembly  198  is shown with a pilot member  110 , slitter  112 , separation member  114 , an expander  116  and a pipe puller  118  as disclosed with reference to  FIG. 6  above. Additionally, as shown in  FIG. 11 , the pipe expander assembly further comprises a beacon assembly  220 . The beacon assembly  220  emits a transmission capable of passing through subsurface. 
         [0043]    With reference now to  FIG. 13  which is section D-D of  FIG. 11 , the beacon assembly  220  comprises a beacon  222  and a body  224  with a towing eye  226 . Longitudinal slots  228  are formed in the body  224  to allow the signal generated by the beacon  222  to be emitted from the body. In a preferred embodiment, five slots  228  are utilized in the body  224 . The beacon assembly  220  further comprises a protective sleeve  230  surrounding the beacon to protect the beacon during operation of the expander assembly  198 . The sleeve  230  may be made of a protective electromagnetically transparent material such as plastic. The towing eye  226  allows connection to the expander  116  through use of a bolt  231  or other attachment means. 
         [0044]    The body  224  is attached to a rear cap  232  that comprises a clevis  234 . The rear cap  232  is threaded into the body  224  using threads  236  or may comprise a pinned connection (not shown) or other connection mechanism. The rear cap  232 , when removed from the body  224 , allows access to the beacon  222  within the beacon assembly  220 . The clevis  234  is provided for attachment to the pipe puller  118  using a bolt  238  or other connective mechanism. 
         [0045]    In operation, the beacon  222  transmits a signal, such as a radio, Bluetooth, infrared, magnetic, or other transmission, to an above ground receiver, or tracker. Methods and apparatus for tracking an underground beacon are known in the horizontal directional drilling (HDD) field, and such methods and apparatus are shown in U.S. Pat. No. 7,624,816 issued to Cole, et. al., U.S. Pat. No, 8,482,286, issued to Cole, and U.S. Pat. No. 8,829,906, issued to Gard, et. al, the entirety of which are incorporated herein by reference. 
         [0046]    With reference now to  FIG. 14 , the winch assembly  206  of  FIG. 10  comprises a capstan  300 . The capstan  300  comprises an upper bullwheel axle  302  and a lower bullwheel axle  304 , each of which support a bullwheel, such as upper bullwheel  306 . Lower bullwheel is not shown in  FIG. 13 . The upper bullwheel  306  comprises a bullgear  308  and grooves  310 . Hydraulic motors (not shown) or other motive force devices turn the bullgear  308  of both bullwheels, causing the wire rope (not shown) to be forced by friction in a direction by the grooves  310 . Mounting feet  312  are provided for attachment to the support assembly  200  ( FIG. 10 ). Axis  314  represents the position of wire rope  16  ( FIG. 10 ) when in use with capstan  300 . 
         [0047]    One of ordinary skill in the art will appreciate that while the Figures show one configuration for the subject invention, modifications to the particular shape and organization of the pipe expander assembly  10  may be taken without departing from the spirit of the disclosed invention. For example, the slitter  18  may be integrally formed with the expander rather than abutting the expander at the cylindrical joint. Likewise, the pipe puller  12  may be integrally formed rather than connected at a clevis joint.