Abstract:
A protective sleeve is applied as a permanent outer cladding shield over a joint infill at the welded end closure portions of adjacent coated sections of pipe for a pipeline in or beneath a body of water. The sleeve once installed forms a seal against entry of water to protect the pipe from corrosion. The sleeve takes the form of a sheet of synthetic resin mounted to form a cylinder about the area to receive the joint infill. A flap is provided on a longitudinal edge of the sheet to prevent leakage and hold the cylindrical shape of the infill when to be applied. Electrically conductive mesh or wire element bands are mounted with an inner side of the sheet to circumferentially engage the coated sections of the pipe on either side of the infill. The sheet and conductive bands are held in place to be applied by an applicator clamp. Electrical current is applied to the mesh bands to fuse the sleeve circumferentially to the coated cover sections of the pipe. The infill is applied in the interior of the sleeve. The flap is removed and a longitudinally extending strip of comparable material to the sleeve with an electrically conductive strip is positioned over a gap formed when the sleeve flap is removed. Electrical current is applied to fuse a longitudinal seam of the sleeve between the end fused portions. A cladding or seal against entry of water is formed between the sleeve and the pipe covering. A fill/vent port is formed in the sleeve and allows introduction of the joint infill. The closure is later hermetically sealed to the sleeve over the injection port by electrical heating of conductive elements mounted on a surface of the closure.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS:  
       [0001]     The present application relates to joint infill cladding and method of applying same, as does commonly owned U.S. patent application Ser. No. ______ entitled “Joint Infill Cladding and Method of Applying Same” (Attorney Docket No. 085356.000020), filed of even date herewith, and of which applicant is inventor. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates generally to providing water impenetrable outer cladding to pipeline coatings, and to methods and apparatus for installing same, to better protect joint infill coatings applied to exposed ends of coated pipeline to be laid in bodies of water.  
         [0004]     2. Description of the Related Art  
         [0005]     It is conventional in the offshore pipeline industry to use weighted coated pipe on pipelines which are being laid on or under the floors of bodies of water. Originally, the weight coatings of each section or length of pipe were of concrete with end metal closure portions of the pipe left bare or unprotected. The end closure portions of adjacent lengths of pipe were welded together on a pipe laying barge as the pipeline was being formed. The bare metal was then covered with a film or sheet of corrosion resistant material. A joint infill resulting from injection of chemicals which reacted and formed an open cell polyurethane foam was then used to fill the annular socket or space between weight coatings. U.S. Pat. Nos. 5,900,195 and 6,402,201, each commonly owned by the assignee of the present application, are examples of this open cell foam infill technology.  
         [0006]     More recently, the pipe lengths have been weight coated with a solid synthetic resin, usually being polypropylene and polyethylene synthetic resin coatings to serve as thermal insulation. This has been increasingly the case as offshore production has moved into deeper bodies of water. In some cases a concrete weight coating has been applied on top of the synthetic resin insulation. A similar solid synthetic resin was also desired for the joint infill material. Solid synthetic resins are impenetrable by water; however, concerns have been raised about water ingress through even the relatively small spaces or gaps between the joint infill and the synthetic resin insulation coatings. This has been a particular concern due to the increased hydrostatic pressures beneath bodies of water, particularly in deeper bodies of water.  
         [0007]     Other patents, such as U.S. Pat. No. 6,059,319, were directed to forming a cylindrical sleeve seal over the gap between adjacent lengths of plastic coated pipe. Filler panels of butyl rubber, bitumastic, rubberized bitumen or similar materials of a size approximating the interior space within the cylindrical sleeve were used in an attempt to provide corrosion protection. However, gaps and spaces were often present between the various elements, such as between the filler panel material, the pipe coating and the cylindrical sleeve seal. There was thus a risk of fluid leakage and corrosion. For offshore pipelines, particularly in deeper bodies of water, the hydrostatic pressures increased the concerns of fluid leakage through these gaps and spaces and resulting possible corrosion.  
       SUMMARY OF THE INVENTION  
       [0008]     Briefly, the present invention provides a new and improved protective outer cladding for coated pipelines being laid in a body of water, and a method of applying a protective outer cladding over Welded end portions of adjacent coated sections of pipe for such a pipeline. A sheet of synthetic resin with spaced electrically conductive elements is applied to form a cylindrical sleeve about the welded end portion, with the conductive elements being positioned circumferentially about the coated end portions. The electrically conductive elements are connected to a source of electrical current. Electrical current is sent into the electrically conductive elements to head adjacent portions of the cylindrical sleeve to bond the sleeve together with the weight coating and to seal the sleeve over the joint infill coating. One or more chemicals or components are introduced into the interior of the cylindrical sleeve to allow a synthetic resin to form and fill the interior of the sleeve as joint infill insulation between the adjacent pipe sections. The present invention also provides a new and improved cladding applicator clamp to maintain the protective outer cladding in place as it is being applied over joint infill on coated pipe sections for a pipeline. The coated sections may include insulation coating and weight coating.  
         [0009]     The weight-coated portions of the pipeline in a preferred embodiment are coated with a synthetic resin weight coating, and the synthetic resin formed during the step of introducing components is preferably a solid polyurethane which bonds with the synthetic resin coating along the length of the pipe.  
         [0010]     To better understand the characteristics of the invention, the description herein is attached, as an integral part of the same, with drawings to illustrate, but not limited to that, described as follows.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     A better understanding of the present invention can be obtained when the detailed description set forth below is reviewed in conjunction with the accompanying drawings, in which:  
         [0012]      FIG. 1  is an isometric view of a joint infill cover sleeve with an electrical heating/welding element according to the present invention.  
         [0013]      FIG. 2  is an isometric view of a seam sealing strip according to the present invention.  
         [0014]      FIG. 3  is an isometric view of a pipe joint before application of the joint infill cover sleeve of  FIG. 1 .  
         [0015]      FIG. 4  is a view of the sleeve of  FIG. 1  being applied to the pipe joint of  FIG. 3 .  
         [0016]      FIG. 5  is an isometric view of a cladding applicator clamp according to the present invention.  
         [0017]      FIG. 6  is an isometric view of the applicator clamp of  FIG. 5  in place over the joint infill sleeve and pipe of  FIG. 4 .  
         [0018]      FIG. 7  is a view of joint infill material being injected within a port in the sleeve of  FIG. 6 .  
         [0019]      FIG. 8  is an isometric view of a joint infill sleeve according to  FIGS. 6 and 7  after the joint infill has been applied.  
         [0020]      FIG. 9  is a view of the seam sealing strip of  FIG. 2  being applied to the joint infill sleeve of  FIG. 8  as a completed joint infill shield according to the present invention.  
         [0021]      FIG. 10  is a view of electrical connection being made to the seam sealing strip of  FIG. 9 .  
         [0022]      FIG. 11  is a view of a completed joint infill cladding according to the present invention applied to the pipe joint of  FIG. 3 .  
         [0023]      FIG. 12  is an isometric view of an insert element used along the longitudinal seam in the joint infill sleeve in an embodiment of the present invention. 
     
    
       [0024]     To better understand the invention, a detailed description of some of the modalities, as shown in the drawings for illustrative but not limiting purposes, is included as part of the description herein.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]     Although the following detailed description contains many specific details for purposes of illustration, anyone of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the invention. Accordingly, the exemplary embodiment of the invention described below is set forth without any loss of generality to, and without imposing limitations thereon, the claimed invention.  
         [0026]     In the drawings,  FIG. 1  shows a flat rectangular sheet S formed of a suitable synthetic resin, such as polypropylene or polyethylene which is wrapped into a cylindrical sleeve in order to be applied as protective cladding in connection with joint infill on coated sections of a pipeline. The synthetic resin material of the sleeve S has a typical thickness from about 0.125″ to 0.5″ or larger. The dimensions of the sheet S are such that it extends as indicated at  11  laterally a sufficient distance to span a gap G ( FIG. 3 ) at welded end portions  10  and  12  of the pipeline P. The welded end portions or stubs  10  and  12  are located between coatings  14  and  15  which form selected coated sections  16  and  17  of the pipeline P. The dimensions of the sheet S are also such that it extends laterally or transversely as indicated at  13  a sufficient distance to circumferentially enclose the gap G ( FIGS. 3 and 4 ) with adequate overlap of portions of the wrapped sheet S to allow forming a protective cladding for sealing against water ingress according to the present invention.  
         [0027]     According to the present invention, sheet S is wrapped about the pipeline P to form a cylindrical sleeve C ( FIG. 4 ) which is a protective outer cladding shield over a weld joint  18  formed between the welded end portions  10  and  12  adjacent the coated pipe sections  16  and  17  of the pipeline P. The coatings  14  and  15  applied to the pipeline are a suitable, fluid impenetrable, hard, high-density synthetic resin such as a high-density polypropylene or polyethylene, also known as HDPP or HDPE, respectively. It should be understood that, if described, a number of other water impenetrable resins may be used in place of HDPP or HDPE. The coatings  14  and  15  are factory applied and serve to provide thermal insulation for the fluids transported through the pipeline. If desired, an outer weight coating of concrete may be applied as a weight coating as a part of coatings  14  and  15  on top of the thermal insulative HDPE or HDPP.  
         [0028]     As is conventional, the end portions  10  and  12  of the pipe sections  16  and  17  are welded together to form the weld joint  18 . The exposed end or stub portions  10  and  12  of the pipe sections  16  and  17 , respectively, in the area of the gap G are not weight coated prior to the welding of sections  10  and  12  together. If desired, a thin corrosion protective coating may be installed over the end portions  10  and  12  after the weld joint  18  is formed and the weld area and end portions cleaned.  
         [0029]     As will be set forth below, the sheet S is formed into the cylindrical sleeve C, and then an annulus or cylindrical space  24  is formed about the exposed pipe sections  10  and  12  adjacent the weld joint  18 . The annulus  24  is preferably filled such as by pouring, injection or the like with a chemical composition such as a suitable synthetic resin, in the form of a polyurethane or epoxy which sets or hardens in the annulus to form a HDPE or other hard synthetic resin infill I. As an alternative, chemical components which mix and then harden to form a hard polyurethane or epoxy joint infill I for insulation may be injected into the annulus  24 . The composition or components which form the joint infill I also bond with the adjacent weight coatings  14  and  15  of the pipeline P and also with synthetic resin interior surface portions  30  of the sleeve S for circumferential positioning ( FIG. 4 ) on coated sections  16  and  17  on each side of the welded end portions  10  and  12  of the pipeline P. Due to such bonding, no flow path for water ingress is formed between the end portions  10  and  12  adjacent weld joint in the pipeline P.  
         [0030]     As shown in  FIG. 1 , a set of electrically conductive elements strips or bands  28  of a welding element/mesh are located at side edges  30   a,    30   b  of the sheet S. The welding elements  28  are pre-attached, such as by means of tack welding, to locations on the side edges  30   a,    30   b  on the interior surface  30  of the sheet S. The welding elements  28  are formed of a suitable conductive metallic material, such as a number of alloys including stainless steel, nickel-chromium, aluminum, copper, copper-tin, or other electrically conductive material. It should be understood that the foregoing materials for the welding element  28  are given by way of example, and that others may be used, if desired.  
         [0031]     The welding elements  28  in response to the flow of electrical current heat and melt the adjacent synthetic resin materials. The heated, melted synthetic resin bonds overlapping or adjacent portions of the cylindrical sleeve C together and also to the weight coatings  16  and  17 . Side edge portions  30   a  and  30   b  of the sleeve C are disposed circumferentially at opposite sides spaced from each other. When the sleeve S is formed into the cylindrical sleeve C and heated by welding elements  28 , the end or edge portions  30   a  and  30   b  provide circumferential bonding together of the coiled cylindrical portions of the sheet S at each end of the annulus  24 . The circumferential end portions  30   a  and  30   b  also bond the sleeve C circumferentially to the coated portions  16  and  17 , respectively.  
         [0032]     A flap  30   f  is formed along one of the longitudinally extending side edges  30   e  of the sleeve C. The flap  30   f  forms a longitudinal temporary cover along an area of a longitudinal seam  31  along the longitudinally extending side edge portion  30   e  when the sheet S if wrapped about the coated portions  16  and  17  to form the cylindrical sleeve C.  
         [0033]     Electrically conductive contacts or leads  32  and  34  are installed or attached at opposite ends  28   a  and  28   b  of each conductive strip or band  28  to connect the band  28  to a suitable power supply so that electrical current may be provided from the power supply to the conductive strip welding element or band  28 . The end portions  28   a  and  28   b  of each conductive strip  28  are located so that when the sheet S is wrapped on the pipeline and the cylindrical sleeve C is formed; such end portions are spaced from each other on opposite sides of the longitudinal seam  31 .  
         [0034]     In some instances, the electrical conductive leads  32  and  34  are formed to be connected with the conductive strip or band as part thereof as shown in  FIG. 1 . As an alternative removable conductive probes or contacts separately insertable and removable may be used. In this manner, the synthetic resin bonds or welds formed when elements  28  heat due to electrical current flow are each a circumferential synthetic resin bond from one end  28   a  to the other end  28   b  of the elements  28 .  
         [0035]     Sizes of the sleeve C can vary to accommodate pipe sizes for example, 2″ thru 60″ diameters. The sleeve C in most cases is preferably pre-abraded on the inside surface  30 . If desired, it may be factory corona-treated, or treated in the field by means of flame treatment, or both, to enhance the bond at the interface of the inside of the sleeve C with the solid polyurethane infill I that is formed in the annulus  24 .  
         [0036]      FIG. 2  of the drawings shows alternate forms of a synthetic resin seam sealing strip  38  provided according to the present invention to seal the longitudinal shown at  31  and along its longitudinal extent, as will be set forth below. The strip  38  is formed of a like or comparable synthetic resin to the sheet S and has an electrically conductive strip or band  39  therewith along a contact surface  38   a.  The conductive strip  39  is of a like or comparable structure and material to the welding element  28 . As is the case with welding element  28 , conductive strip  39  may have electrically conductive bands or contacts  39   a  and  39   b  formed as part thereof. Alternatively, removable conductive probes or contacts  40  which are separately insertable and removable may be used to provide current to the conductive strip  39 .  
         [0037]     A cladding applicator clamp L ( FIGS. 5 and 6 ) is also provided according to the present invention to maintain the protective cladding sleeve C firmly in position on the pipeline P as the protective cladding sleeve C is being applied to the pipe joint. The cladding applicator clamp L include side clamp bands  50  located at laterally spaced positions from each other and connected together by a suitable number of connector bars or beams  54 . One or more of the connector bars  54  has attachment lugs or flanges  56  formed thereon at suitable locations. Connector eyelets  58  are formed in the attachment lugs  56  so that chains or other suitable forms of lifting and moving mechanisms may be inserted and connected to move the applicator clamp L into position during placement of the protective cladding sleeve C onto the pipe joint to receive the water impermeable infill.  
         [0038]     The side clamp bands  50  are formed of a set of arcuate clamp segments  60  and  62  which are pivotally connected together by hinge pins  64  for relative movement to fit the clamp L about the pipeline P adjacent the pipe joint to receive the cladding sleeve C. The arcuate clamp segments  60  and  62  allow the applicator clamp L to be fitted over a range of diameters of coated pipe. Grip pads  66  of a suitable insulative, heat-resistant resilient material are mounted along inner surfaces  60   a  and  62   a  of the accurate clamp segments  60  and  62 , respectively. The grip pads  66  fit over and engage the cladding sleeve C at each side portion over the conductive heating elements  28 .  
         [0039]     Reversible, fluid-powered pistons  70  are pivotally mounted at their inner ends  72  by pivotal connections  74  mounted with mounting flanges  76 . The pistons  70  may also be electrically driven, if desired. Each of the pistons  70  is mounted on one of the side clamp bands  50  adjacent a gap  78  between end portions  50   a  and  50   b  of the side clamps  50  to allow the applicator clamp L to be brought into position and fitted over the pipeline P for installation of the protective cladding sleeve C.  
         [0040]     A connector ball or head  80  is formed at an outer end  82  of a piston shaft  84  extending outwardly from each of the power pistons  70 . The piston shafts  84  and connector balls  80  are reciprocally movable under power from the pistons  70 .  
         [0041]     Socket plates or blocks  86  are mounted on the clamp bands  50  on opposite sides of the gap  78 . Each of the socket plates has an engagement socket  88  with an internal surface matching the shape of the connector heads  80  to receive and engage one of the connector heads  80  on the piston shafts  84 . When the connector heads  80  are spherical or globe-shaped as shown, the sockets  88  are correspondingly spherically shaped.  
         [0042]     The pistons  70  move the piston shafts  84  outwardly so that the connector heads  80  may be fitted into the connector sockets  88  and position the applicator clamp L on the pipeline P firmly in place enclosing over and tightly engaging the protective cladding sleeve C therein. Preferably, a release pad or liner sheet  90  ( FIG. 6 ) is preferably applied and positioned over the cladding sleeve C enclosing the cladding sleeve C within its extent between the clamp bands  50 . The pistons  70  then move the shafts  84  and connector heads  80  in an opposite direction to close the side clamp bands  50  together firmly in place over and tightly engaging the cladding sleeve C and the release pad  90  on the pipeline P. A suitable number of releasable belts  92  ( FIG. 6 ) may also be fitted over the release pad  90  and cladding sleeve C between the side clamp bands  50  for additional holding strength and support.  
         [0043]      FIG. 4  illustrates initial parts of the joint infill protective sleeve application process of the present invention. The sheet S is applied by hand as shown, or by machine to the field joint configuration of the pipeline P in a cylindrical wrap manner to the coated pipe sections  16  and  17 . Electrical connection is then made in the manner described above to make contact with each of the welding elements  28 . Typically, coatings  14  and  15  are either polypropylene or polyethylene. However, it should be understood that other suitable strength and density synthetic resin may be used as factory pipeline coatings  14  and  15 . The sleeve S is preferably also manufactured of the same or very similar synthetic resin material as the factory coatings  14  and  15  on the pipeline.  
         [0044]      FIG. 6  shows the cylindrical sleeve C secured in place using cladding applicator clamp L. As mentioned, the circumferential separate clamp bands  50  are placed directly on top of the areas of the sleeve C to be circumferentially welded to the factory coatings  14  and  15 .  
         [0045]      FIG. 7  shows an injection port or filling/vent port  94  which is drilled or otherwise formed in the sleeve C, for example at the job site. In  FIG. 7 , the port  94  is shown as located in the top center of the sleeve C just next to the cutback or edge of the factory applied weight coating  16  or  17  at a high or uppermost location on the circumference of the weight coating. It should be understood that the injection or infill inlet port  94  may be located at other positions on the sleeve C, if desired. For example, in some situations it may be desirable to locate the port  94  at the bottom center or other lower position of the sleeve C. An example of this type could be when the infill is an elastomer being infilled into the annulus  24  from a bottom or lower position. As an alternative feature, the injection port  94  may be pre-formed in the sheet S at a suitable location before delivery to the job site. It is also possible in some cases for the annulus  24  to be filled from the bottom through a pre-drilled and/or threaded injection port at the bottom of the cylindrical sleeve C.  
         [0046]     A solid polyurethane-forming material  100  is pumped or poured through the port  94  into the annulus  24  with a hose and nozzle  102  until the volume of the annulus  24  is full. The solid polyurethane material  100  quickly reacts and changes state from liquid to solid, hardening and forming the fluid impenetrable joint infill I. In most cases the polyurethane material  100  used has no expansion on exposure to air. However, in some cases the infill material  100  may be of a lower density that does expand somewhat. The polyurethane materials used for this application may range in density from 2 to 80 pounds per cubic foot.  
         [0047]     As shown in  FIG. 8 , after injection of the solid polyurethane  100  to form the joint infill I, the applicator clamp L has been released from engagement with the pipe joint after the infill material  100  has been put into the annulus  24  to form the joint infill I. The flap  30   f  is still present with the cladding sleeve C over the longitudinal seam  31 . The flap  30   f  is then cut off or otherwise removed.  
         [0048]     The longitudinal sealing strip  38  is mounted ( FIG. 9 ) on the cladding sleeve C above the seam  31 , with the conductive strip  39  on an innermost position. Electrical connection is then made in either of the manners discussed above. A pressure pad, such shown at  104  is mounted, held otherwise secured in place by means of a suitable mechanical clamping system, as described in commonly owned U.S. Patent Application entitled “JOINT INFILL CLADDING AND METHOD OF APPLYING SAME” Ser. No. ______, filed of even date herewith, of which applicant is inventor. If desired the clamping system may be automated in a manner similar to the air-impact wrench or hydraulic clamping systems described in such applications, or in some other types suitable for the circumferential welding.  
         [0049]     To complete the water impermeable hermetic seal, an injection closure of comparable material to the sleeves and of a size to port form a closure over the injection port  94  is used for closure purposes, as is also described in the commonly owned U.S. patent application Ser. No. ______ filed of even date herewith and of which applicant is inventor.  
         [0050]     Electrical current is caused to flow through the conductive strip  39  along its longitudinal extent over the seam  31  in cladding sleeve C, and over portions  16   a  and  17   a  of the coated portions  16  and  17  adjacent the seam  31  and cladding sleeve C. The conductive strip  39  in a like manner to elements  28  heats and melts the adjacent synthetic resin materials of the sealing strip  38 , the cladding sleeve C and the adjacent portions  16   a  and  17   a  of the coated pipe. The melted synthetic resin materials bond together, forming a hermetic seal or water impermeable barrier along the longitudinal seam  31  in the cladding sleeve C and also with the adjacent pipe coating ( FIG. 11 ).  
         [0051]      FIG. 12  show an insert element E used as an alternative in place of flap  30   f  in the sleeve S to block blockage of infill material from the annulus  24  and to thereafter coact with the sealing strip  38 . The element E is of a non-conductive, thermally-fusible synthetic resin of a suitable type and takes the form of an elongate beam or bar resting along tapered end portions  120  and  122  on opposite sides of the gap G on coated sections  16  and  17 . The element E thus extends in length across the gap G and has outer surface  124  which is located level or flush with that of the outer surface of the coated sections  16  and  17 . The insert element E is put into place as shown before mounting the sheet S in position to form the sleeve C.  
         [0052]     As mentioned, when using the insert element E it is not necessary for the sheet S to have flap  30   f.  When the sheet S is put into place, it is located so that the insert element E is located at a position coincident with and along the extent of the longitudinal seam  31 . The insert element E is wider than the seam  31 , so that with the applicator clamp L engaged, no path for flow or escape, of infill material from seam  31  is present. Further, the thermally fusible nature of the synthetic resin in the insert element E permits it to heat, melt and fuse with the other synthetic resin materials, assisting in formation of the water impermeable barrier for the pipe joint according to the present invention.  
         [0053]     According to the present invention, a permanent outer cladding is formed by bonding of the synthetic resin materials together in the manner described above. The cladding sleeve C bonds to the infill I and also to the factory applied portions  16  and  17  of the pipeline P. The infill I also bonds to the factory coated sleeve  30  and also bonds to synthetic resin in the coated portions  16  and  17 . The sleeve  30  also bonds to itself along the area of the longitudinal seam  31 .  
         [0054]     The joint in the pipeline P so formed is thus impermeable to water and in effect a hermetic seal. The joint formed according to the present invention provides an effective, water impermeable seal to the factory applied pipeline coatings and affords better protection for both the joint infill insulation and the pipeline insulation coatings.  
         [0055]     The invention has been sufficiently described so that a person with average knowledge in the matter may reproduce and obtain the results mentioned in the invention herein Nonetheless, any skilled person in the field of technique, subject of the invention herein, may carry out modifications not described in the request herein, to apply these modifications to a determined structure, or in the manufacturing process of the same, requires the claimed matter in the following claims; such structures shall be covered within the scope of the invention.  
         [0056]     It should be noted and understood that there can be improvements and modifications made of the present invention described in detail above without departing from the spirit or scope of the invention as set forth in the accompanying claims.