Abstract:
Apparatuses for removing a circumferential seal from the internal wall of a pipe comprise a tool for forward movement into an entry end of the pipe towards and into contact with the seal in the pipe, the tool having means for engaging the seal with the forward movement and with further forward movement of the tool release of the seal from the pipe wall and means for capturing and retaining the released seal with still further forward movement whereby on subsequent rearward movement of the tool the seal is withdrawn from the entry end of the pipe.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    None. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    Not applicable. 
       REFERENCE TO A BIOLOGICAL SEQUENCE LISTING 
       [0004]    Not applicable. 
       BACKGROUND OF INVENTION 
     Field of the Invention 
       [0005]    The present invention relates to apparatus for removing a circular seal from the internal circumference of a pipe and is in particular a specific tool to remove a circular seal from the internal circumference of a pipe. It is in the field of pipeline maintenance, more specifically in the field of pipe joint seal removal. 
       Description of the Related Art 
       [0006]    The invention is particularly directed to the removal of large diameter seals e.g. between 16″ and 48″ internal diameter from large diameter pipes of the same diameter. These pipes are made of cast iron. The seal may be of rubber or similar flexible material and may be a so-called Weko (trademark) seal. This forms a seal between two adjoining lengths of pipe. The seal may be kept in position by a one or more spring steel split rings which are positioned against the seal to keep it in place. Currently the seal and ring or rings are positioned manually by a man crawling up the pipe from an open end to place the ring in position at the joint between the two lengths of pipe. 
         [0007]    The removal of the seals is for the purpose of pushing a plastic pipe through the old cast pipe, the seals are basically in the way of inserting the new plastic pipe and have to be removed before installation of the new plastic pipe. 
         [0008]    They are removed in the same way that they are positioned in the first place with a man crawling up the pipe to manually lever off the seal and the associated ring or rings. 
         [0009]    These pipes contain the residues of poisonous gases and it is undesirable for a man to crawl up the pipes and breathe in these gases. 
       BRIEF DESCRIPTION OF THE INVENTION 
     Objects of the Invention 
       [0010]    It is therefore an object of the present invention to provide means whereby an internal pipe seal can be removed without a human having to enter the pipe. 
       SUMMARY OF THE INVENTION 
       [0011]    According to the present invention, there is provided apparatus for removing a circumferential seal from the internal wall of a pipe, the apparatus comprising a tool for forward movement into an open entry end of the pipe towards and into contact with the seal in the pipe, the tool having means for engaging the seal with the forward movement and with further forward movement of the tool release of the seal from the pipe wall and means for capturing and retaining the released seal with still further forward movement whereby on subsequent rearward movement of the tool the seal is withdrawn from the open entry end of the pipe. 
         [0012]    Preferably the means for engaging and releasing the seal is a nose. 
         [0000]    Suitably the means for capturing and retaining the released seal comprises a seal trap which, in embodiments, comprises a pivotal arm which is pivotally mounted on the tool to rest in a socket and to pivot on the tool with engagement with the seal and capture and retain the released seal with the movement of the pivotal arm and its return to the socket. 
         [0013]    Conveniently the tool has two ends with at either end means for connection to a winch whereby in use the tool is attachable to winch cables at either end of the tool to pull the tool into the pipe from one open end of the pipe by way of one cable extending through the pipe and to withdraw the tool from another open end of the pipe by way of the other cable extending through the pipe. Optionally, the tool may be configured so that the winch cables are attached at one or more other locations on the tool. The term “winch” herein is intended to include any cable pulling device. 
         [0014]    Preferably a cradle is provided to locate the tool at the entry end of the pipe, the tool being lowered into the cradle before attachment to the winch cable and movement through the pipe. 
         [0015]    Suitably the tool has a body provided with wheels to permit the tool to be moved along the pipe. 
         [0016]    Conveniently there are six wheels arranged in two pairs of three equiangularly spaced wheels around the body of the tool. 
         [0017]    Preferably the wheels are mounted on wheel arms which are adjustable by screws to engage with the internal wall of the pipe. 
         [0018]    Suitably the tool has a camera to permit the internal wall of the pipe to be viewed as the tool is moved along it so as to identify the seal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a view of a cradle from one end for location at one end of the pipe. 
           [0020]      FIG. 2  is a longitudinal view of the cradle. 
           [0021]      FIG. 3  is an internal view of the pipe showing equiangularly disposed wheels of the tool engaging the internal wall of the pipe to move the tool through the pipe. 
           [0022]      FIG. 4  is a longitudinal view of the tool inside the pipe in use. 
           [0023]      FIG. 5  is a concrete pad on which the cradle is mounted in use. 
           [0024]      FIG. 6  is a plan view of the cradle. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    Referring now to the drawings, in which like reference characters refer to like elements among the drawings, and particularly to  FIGS. 3 and 4 , the apparatus comprises a tool  1  which locates within the interior of the pipe  2  which typically has an internal diameter of between 16″ and 48″ and has been cut away for access of the tool  1  to the pipe  2 . The pipe  2  has a flexible rubber seal  3  joining two sections  4  and  5  of pipe together, which seal  3  is to be removed by the tool  1 . 
         [0026]    The tool  1  has a central cylindrical body  6  from which there extends two pairs  7 ,  8  of screw-adjustable wheels  9 ,  10  and  11  mounted on wheel arms. The tool  1  is adjusted to suit the internal diameter of the pipe  2  by means of adjustment of the screw adjusters on the wheel arms to adjust the position of the wheels  9 ,  10  and  11 . Other means of adjustment of the wheel arms such as jacks or outward biasing means are included within the scope of this invention. 
         [0027]    Located at the front end of the tool  1  is a blade-like device  12  with at the front end of the tool  1  a sharp nose  13  which with forward movement of the tool  1  to the right hand side of the pipe  1  engages the seal  3  (and any steel expansion strips if present) and lifts the seal  3  and strips away from their seat in the pipe  2 . 
         [0028]    Also formed in the blade  12  is a means for capturing and retaining the released seal  3  and any associated expansion strips. In the depicted embodiment, the means is in the form of a pivotal arm  14  which is pivoted at one end, rests in a socket  15  at the other end and forms a seal trap with an aperture  16  in the blade  12 . When the tool  1  is moved forward and the seal  3  and associated strips are released by the nose  13 , further movement forward of the tool  1  causes the released seal  3  and strips to engage with the pivotal arm  14  and tilt it backwards to capture the seal  3  and strips in the aperture  16 . The pivotal arm  14  then tilts back to locate in the socket  15  and trap the seal  3  and strips. Other seal trap means for retaining the seal and associated strips are included within the scope of this invention, such as, by example and not limitation, an aperture  16  shaped to hold the seal and strips by gravity, or a pivotal arm  14  biased to return to socket  15  under a force other than gravity. 
         [0029]    To move the tool  1  forwards the tool  1  is attached to a front cable (not shown) via a winch eye  17  at the forward end of the tool  1 . The cable is then pulled through the pipe  2  in the right hand direction by means of a winch (not shown) to move the tool  1  and thereby engage, release and capture the seal  3 . 
         [0030]    The rear end of the tool  1  is connected to a rear cable by a winch cable eye  18  on the body  6  of the tool  1  so that after the seal  3  and any associated strip or strips have been removed and captured, the tool  1  can be pulled out of the pipe  2  in the left hand direction by means of the rear cable wound onto a winch (not shown). 
         [0031]    A camera  19  is mounted on the body  6  of the tool  1  to identify the position of the tool  1  with respect to the seal  3  and strips so that the nose  13  can be accurately positioned to remove the seal  3  and strips, capture them and retain them for removal from the pipe  2 . 
         [0032]    Referring to  FIGS. 1, 2, 5 and 6  initially a cradle  20  from which the tool  1  is launched from the entry end of the pipe  1  is located on a concrete pad  21  ( FIG. 5 ) which is constructed so that the top of the concrete is about 10 inches from the bottom of the pipe  2 . The cradle  20  has two vertical spaced legs  22 ,  23 , a base  24  and a removable top  25  through which the tool  1  can be lowered into position in the cradle  20 . Then the top  25  can be replaced and secured to the side legs  22 ,  23 . 
         [0033]    After the concrete has been allowed to harden, the cradle  20  is lowered onto the pad  21 . The cradle  20  has a collar (not shown) at one end. The collar is placed over the excavated pipe  2  and is centralized, four hydraulic jacks (not shown) being placed under each corner of the cross beams (not shown) of the cradle  20 . The jacks are adjusted to raise and level the cradle  20  to the internal diameter of the pipe  2  at which stage the cradle and collar  20  are pushed towards the cut pipe  2 . When the collar on the end of the cradle  20 , being of a greater diameter than the pipe, slides over the pipe 150 mm, a series of bolts are tightened to hold the cradle  20  steady. 
         [0034]    After the cradle  20  has been raised and centralized to the appropriate height the tool  1  is lowered into the cradle  20  and is connected to the front cable as previously described. The pairs of screw adjusters  7  and  8  on the tool  1  are then adjusted so the position of the tool  1  is centered within the pipe  2 . 
         [0035]    The winch assembly (not shown) is a Groundowinch (trademark) RW-30 for the rear of the tool  1 . It is lowered onto the cradle vertical legs  22  and  23  and then bolted down (by a Hiab or crane). A drop arm (of the Groundowinch RW-30) is fixed on the winch to allow the cable to pull at the center line of the excavated pipe  2  and is adjusted to fit a back plate (not shown) on the cradle  20  and is bolted thereto. The cable is then attached to the rear of the tool  1 . 
         [0036]    At this stage the camera  19  on the tool  1  is switched on and a signal is sent to a smart phone or i-pad to display the interior of the pipe  2 . 
         [0037]    As previously described the front winch cable is attached to the eye  17  and then pulls the tool  1  from the rear end of the pipe  2  forwardly. The rear winch is put into free wheel and the tool  1  is pulled to the first seal  3  in the pipe  2 . The nose  13  engages with the seal  3  and as the tool  1  is winched forward the nose  13  lifts the seal  3  away from the bottom of the pipe  2  breaking the bond between the seal  3  and the pipe  2  as the tool  1  progresses in a forward motion. The nose  13  comes out from the underside of the seal  3  and the pivotal arm  14  falls back into the socket  15  thus capturing the seal  3  and expansion strips as previously described. This will be repeated two or more times to remove two or more further seals  3  as the tool  1  moves down the pipe  2 . Once three seals  3  have been captured the winches are stopped and reversed so the rear winch now pulls the tool  1  back to the cradle  20 . The front winch is now in freewheel. 
         [0038]    Once the tool  1  is back in the cradle  20  the seals  3  and strips can be removed from the aperture  16 .