Abstract:
Systems and methods for reinforcing an existing pipeline. In some embodiments, the methods include positioning a pipeline wrapping apparatus on the existing pipeline, wherein the pipeline wrapping apparatus comprises a winding head, feeding a strip of material through the winding head, attaching an end of the strip of material to the existing pipeline, and helically wrapping the strip around the existing pipeline by rotating the winding head and axially translating the winding head relative to the existing pipeline.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Extensive pipeline systems exist for carrying gas or liquid under pressure over long distances. These pipelines are subject to corrosion from the outside as a result of moisture from the surrounding environment and/or from the inside due to the fluid or gas being transported. The corrosion thins the walls of the pipeline, which can eventually lead to the leaking of fluid or gas. Because the contents of the pipeline are under pressure, any leak will rapidly increase in volume. 
         [0002]    Weakened sections of pipeline may be discovered through inspections of the pipeline. Once discovered, various methods exist for externally patching pipelines to repair leaks or reinforce sections of the pipeline with walls that have thinned from corrosion. Repair methods that allow for the pipeline to continue operation without interruption are particularly valuable because of the revenue that is lost by the pipeline owner from any flow interruption, in addition to the problems resulting from supply disruptions to end users of the product flowing through the pipeline. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention generally relates to methods and apparatus for reinforcing an existing pipeline. In some embodiments, the methods include positioning a pipeline wrapping apparatus on the existing pipeline, wherein the pipeline wrapping apparatus comprises a winding head, feeding a strip of material through the winding head, attaching an end of the strip of material to the existing pipeline, and helically wrapping the strip around the existing pipeline by rotating the winding head and axially translating the winding head relative to the existing pipeline. 
         [0004]    In some embodiments, the system includes a movable trailer with a lifting apparatus and a spool of a strip material supported thereon and a pipeline wrapping apparatus. The pipeline wrapping apparatus includes a winding head and a movement assembly. The winding head is configured to receive the strip from the spool and rotate around the existing pipeline. The movement assembly includes a track configured to press against the existing pipeline and axially translate the pipeline wrapping apparatus relative to the existing pipeline. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0006]      FIG. 1  is an isometric view of a pipeline wrapping apparatus in accordance with one embodiment; 
           [0007]      FIG. 2  is an isometric view of the pipeline wrapping apparatus shown in  FIG. 1  after placement on a pipeline in accordance with one embodiment; 
           [0008]      FIG. 3  is an end view of a pipeline wrapping apparatus in accordance with one embodiment; 
           [0009]      FIG. 4  is an isometric view of the pipeline wrapping apparatus shown in  FIG. 3 ; 
           [0010]      FIG. 5A  is a bottom view of a movement assembly for the pipeline wrapping apparatus in accordance with one embodiment; 
           [0011]      FIG. 5B  is a side view of the movement assembly shown in  FIG. 5A ; 
           [0012]      FIGS. 5C and 5D  are detailed views of portions of the movement assembly shown in  FIG. 5A ; and 
           [0013]      FIG. 6  is a side view of a repaired section of pipeline in accordance with one embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    In the drawings and description that follows, like parts are marked throughout the specification and drawings with the same reference numerals. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The invention is subject to embodiments of different forms. Some specific embodiments are described in detail and are shown in the drawings, with the understanding that the disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to the illustrated and described embodiments. The different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. The terms “connect,” “engage,” “couple,” “attach,” or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings. 
         [0015]    In  FIG. 1 , a pipeline wrapping apparatus  101  in accordance with embodiments disclosed herein is shown. The pipeline wrapping apparatus  101  may be transported on a trailer  110  to a location along a pipeline  4 . The trailer  110  may include a crane  111  to place the pipeline wrapping apparatus  101  at selected locations along the pipeline  4 . To allow for the operation of the pipeline wrapping apparatus  101  in remote locations, the trailer  110  may further include a generator  120  to provide electrical power to the pipeline wrapping apparatus  101  and a control unit  121 . One or more spools  130  of a strip material  133  may be disposed on the trailer. A feeding arm  131  for feeding the strip from the spool  130  to the pipeline wrapping apparatus  101  may also be included. The strip material  133  may be, for example, a continuous strip of martensitic steel or low carbon steel with a corrosion protection coating. 
         [0016]    Various non-metallic materials may also be used for the strip material  133 . For example, the strip material  133  may be a thermoplastic, such as polybutylene terephthalate or polypropylene, or a thermoset resin, such as polyester, polyurethane, vinylester, or epoxy. The non-metallic material may be reinforced with glass or other fibers. Thermoplastics and thermoset resins may be produced using pultrusion, which provides a continuous process of producing a substantially constant cross-section. As part of the pultrusion process, the non-metallic material may be reinforced with the fibers while being formed into the strip material  133 . The resulting strip material  133  may be wound onto a spool for use with embodiments of the present disclosure. 
         [0017]      FIGS. 2-4  show the pipeline wrapping apparatus  101  after placement onto the pipeline  4 . Preparation for the use of the pipeline wrapping apparatus  101  depends on the manner in which the pipeline  4  is installed. If the pipeline  4  is buried, a trench is dug around the pipeline  4  to expose the sections to be thickened. With the pipeline  4  sufficiently exposed, the pipeline wrapping apparatus  101  is placed onto the pipeline  4  using the crane  111 . A frame  300  of the pipeline wrapping apparatus  101  has an opening  340  that is sufficiently wide to receive the pipeline  4 . A winding head  301 , which wraps the strip material around the pipeline  4 , includes a removable portion  341  that is sufficiently wide to receive the pipeline  4 . After placement onto the pipeline  4 , removable portion  341  is reattached to the winding head  301  to fully surround the pipeline  4 . 
         [0018]    With reference to  FIGS. 3 and 4 , the wall reinforcing operation may be carried out by feeding the strip material  133  from the spool  130  to the pipeline wrapping apparatus  101 . The strip  133  is fed down from roller  305  onto a carrying roll  302 . Going, in the orientation shown in  FIGS. 3 and 4 , counterclockwise around carrying roll  302 , the strip  133  is threaded through a turnaround roll  303  and a preform assembly  304 , which is configured to bend the strip  133  into a diameter close to the diameter of the pipeline  4 . The end  320  of the strip  133  may then be affixed to the outside of the pipeline  4  using, for example, a quick setting adhesive, a mechanical clamp, or welding. 
         [0019]    After affixing the end  320  of the strip  133 , wrapping the strip  133  around the pipeline  4  is carried out by the winding head  301 . As the winding head  301  winds the strip around the pipeline  4 , additional strip  133  is wrapped around carrying roll  302 . Each rotation of the winding head  301  adds another layer of strip  133  to the carrying roll  302 , which accumulates strip  133  faster than what is wrapped onto pipeline  4  because of the greater diameter. The carrying capacity (indicated by circle  310 ) of the carrying roll  302  may be selected such that after half of the strip  133  from spool  130  is wrapped onto the pipeline  4 , the remaining half of the strip  133  is carried by the carrying roll  302 . 
         [0020]    The winding head  301  moves axially relative to the pipeline  4  during rotating in order to helically wrap the strip  133  around the pipeline  4 . The entire pipeline wrapping apparatus  101  may be movable relative to the pipeline  4  by attaching one or more track assemblies to the pipeline  4 . In one embodiment shown in  FIG. 4 , a movement assembly  402  is used to move the pipeline wrapping apparatus  101  axially relative to the pipeline  4  during rotation of the winding head  301 . 
         [0021]    The movement assembly  402 , which is shown in greater detail in  FIGS. 5A-5D , includes a track  404 , which actuates in a manner similar to treads on a tank or other tracked vehicle. The movement assembly  402  also includes cylinders  403  on opposing ends of the track  404 , which may be pneumatic, hydraulic, or electrically actuated. The cylinders  403  press the ends of the track  404  against the pipeline  4  to provide sufficient frictional force such that movement of the track  404  causes the pipeline wrapping apparatus  101  to move axially relative to the pipeline  4 . Another track  404  and cylinders  403  may be provided on the opposite side of the pipeline  4  to balance the track  404  and cylinders  403  visible in  FIG. 4 . Each track  404  may be mounted on a pivoting anchor  501  that allows the tracks  404  to be tilted along the axis of the pipeline  4  to control the radial position of the pipeline wrapping apparatus  101  around the pipeline  4 . The pivoting anchor  501  may be attached to the tracks  404  with a pivot  502  and to the frame  300  with a pivot  503 , as best shown in  FIGS. 5C and 5D . Cylinders  403  may be attached to the tracks  404  indirectly through the pivoting anchor  501 . 
         [0022]    The movement assembly  402  illustrated in detail in  FIGS. 5A-5D  allows for torque to be applied to the pipeline  4 , which counteracts torque from the winding head  301  as it wraps the pipeline  4 . The alignment of the tracks  404  relative to the axis of the pipeline  4  can be adjusted to maintain the orientation of the pipeline wrapping apparatus  101  on the pipeline during the wrapping process. Increasing the angle of the tracks  404  relative to the axis of the pipeline  4  increases the amount of torque applied to the pipeline  4  by the tracks  404 . The desired angle of the tracks  404  varies, in part, according to the conditions of the exterior of the pipeline  4 . 
         [0023]    The pipeline wrapping apparatus  101  may further include an oscillating adhesive assembly  401  that applies adhesive to the pipeline  4  ahead before the strip  133  is wound onto the pipeline  4 . The adhesive may be provided in tanks (not shown) to a metering pump (not shown) that applies a selected amount of adhesive to the pipeline  4 . The rotational rate of the winding head  301  may govern the volume flow rate of adhesive from the metering pump in order to provide a more precise amount of adhesive to the pipeline  4 . Examples of adhesives that may be used to adhere the strip  133  to the pipeline  4  include liquid epoxies, paste epoxies (single and multi-part), acrylics (e.g., methacrylate), polyurea, phenolic, and anaerobic and polyurethane adhesives. 
         [0024]    An example of a pipeline  4  with walls reinforced in accordance with embodiments disclosed herein is shown in  FIG. 6 . In this embodiment, the pipeline  4  is helically wrapped with two successive layers  2 ,  3  of the strip material  133 . The pipeline wrapping apparatus  101  shown in  FIGS. 3 and 4  may be used to apply both layers  2 ,  3 . The axial movement provided by the movement assembly  402  may be timed with the rotation rate of the winding head  301  in order to control the angle of the layers  2 ,  3  and a gap  5  between the successive wrap of the strip. To apply the first layer  3 , the pipeline wrapping apparatus is axially translated along the pipeline  4  while the winding head rotates. The coordinated axial translation and winding continues for a selected length of the pipeline  4 , which may be selected according to the length of strip  133  stored in the spool  130 . After the winding of the first layer  3 , the pipeline wrapping apparatus is returned to the starting position on the pipeline  4  and the second layer  2  is applied in a manner similar to the first layer  3 . The helical winding of the second layer  2  may be offset by about half the pitch of the helical winding of the first layer  3 . Additional layers may be added to continue to add to the wall thickness of the pipeline  4  as desired. In another embodiment, the pipeline wrapping apparatus  101  may include a second winding head in order to provide the second layer after the first layer as the pipeline wrapping apparatus  101  is axially translated along the pipeline  4 . 
         [0025]    After the layer(s) are added to the pipeline, the pipeline wrapping apparatus may be lifted back onto the trailer to be deployed at another location to be reinforced or repaired. If the length of pipeline to be reinforced or repaired exceeds the length of strip provided by the spool, the pipeline wrapping apparatus may be positioned at the ending point of the prior wrapping location to being the wrapping process again. The trailer may be relocated as necessary to continue the wrapping process. 
         [0026]    In another embodiment, a protective outer layer may be applied to the pipeline after wrapping the layer(s) as described above. The protective outer layer may be, for example, liquid epoxy or urethane. The protective outer layer may be applied using a separate pipeline coating unit, or by adding a pipeline coating module to the pipeline wrapping apparatus that resembles the oscillating adhesive assembly  401  described above. The pipeline coating module may be attached to the pipeline wrapping apparatus on the opposite side of the winding head  301  from the oscillating adhesive assembly  401  so that the pipeline coating module passes over the pipeline  4  after the winding head  301  applies the layer(s)  2 ,  3  for reinforcing the pipeline  4 . The material for the protective outer layer may be provided using a tank on the pipeline wrapping apparatus or by a separate tank connected to the pipeline coating module by a hose. The separate tank may be placed on the trailer. The tank and the hose may be heated to prevent the material from solidifying within or to assist with cross-linking. 
         [0027]    Embodiments disclosed herein reinforce existing pipeline in order to restore damaged pipeline or to upgrade the maximum allowable operating pressure (MAOP). Damage to the existing pipeline that can be repaired through increased wall thickness includes thinned walls from corrosion, stress corrosion cracking (SCC), defective welds, or other external damage. The added wall thickness may restore the pipeline to its original MAOP, or greater. If the pipeline has not sustained damage, the MAOP may be increased by adding wall thickness as disclosed herein. 
         [0028]    While specific embodiments have been shown and described, modifications can be made by one skilled in the art without departing from the spirit or teaching of this invention. The embodiments as described are exemplary only and are not limiting. Many variations and modifications are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited to the embodiments described, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims.