Patent Publication Number: US-2005116468-A1

Title: Threaded connectors for axial alignment of tubular components, and method of installing pipe sections employing such connectors

Description:
BACKGROUND OF INVENTION  
      1. Field of the Invention  
      The present invention is generally related to the field of threaded connectors and to the laying of pipelines, and, more particularly, to threaded connectors for axial alignment of tubular components, and methods of installing pipe sections employing such connectors.  
      2. Description of the Related Art  
      Pipelines or transmission lines are created in a variety of industries to allow the flow of a liquid or gas therethrough. For example, it is very common to position pipelines on the ocean floor to thereby allow the flow of hydrocarbons, e.g., oil and gas, as well as other fluids therethrough. Construction of such pipelines is a very time-consuming and expensive undertaking. The construction process typically involves butt-welding lengths or segments of pipe to one another to create the pipeline or transmission line. The pipelines or transmission lines can be laid on the floor of an ocean or above the surface of the earth, i.e., surface pipelines.  
      With respect to the formation of subsea pipelines, there are a variety of known techniques for forming such pipelines. Such processes typically involve the use of an oceangoing lay-vessel and welding sections of pipe together on board the vessel to thereby create the pipeline. Illustrative techniques for forming such pipelines include so-called “J-lay” techniques wherein the pipeline leaves the lay-vessel in an inclined or even near vertical orientation in order to allow the laying of the pipeline in deep water without stressing the pipeline material excessively. Illustrative examples of the J-lay technique are disclosed in, for example, U.S. Pat. Nos. 6,352,388 B1 and 5,464,307, both of which are hereby incorporated by reference in their entirety. Another known technique is the so-called “S-lay” technique wherein the pipeline leaves the lay-vessel in a substantially horizontal orientation, bends downward over a supporting structure, the so-called stinger, and when approaching the sea bottom bends upward to be laid on the sea bottom. One illustrative description of an S-lay technique is disclosed in U.S. Pat. No. 3,715,890, which is hereby incorporated by reference in its entirety.  
       FIGS. 1A-1C  will now be employed to further discuss an illustrative J-lay technique for laying a pipeline on a seabed. However, it should be understood that the present invention is not limited to use with J-lay techniques or to the formation of subsea pipelines or transmission lines. As depicted in  FIG. 1A , a lay-vessel  10  is used to position a pipeline  12  on the floor  15  of the ocean  14 . At the point in time depicted in  FIG. 1A , previous sections of the pipeline  12  have already been formed, and an upper end  12   e  of the pipeline  12  is positioned above the surface  10   a  of the lay-vessel  10  such that a new pipe section  18  may be welded to the existing pipeline  12 . The pipeline  12  typically extends through a moon pool  10   b  formed in the lay-vessel  10 .  
      A plurality of pipe sections  18  are positioned in a lay-down area  16  on the lay-vessel  10 . In some embodiments, a separate support vessel may be provided alongside the lay-vessel  10  to provide the necessary storage for the pipe sections  18 . Typically, each of the pipe sections  18  will be comprised of multiple pipe lengths. In the depicted embodiment, the pipe sections  18  are comprised of four pipe lengths  18   a ,  18   b ,  18   c ,  18   d , wherein adjacent pipe lengths are butt-welded to one another at weld seams  19 . Typically, the pipe sections  18  are assembled on-shore and then loaded onto the lay-vessel  10  such that they may later be assembled to form the pipeline  12 . The number of individual pipe lengths that make up a pipe section  18  may vary. In the depicted embodiment, four individual pipe lengths,  18   a ,  18   d , make up the pipe section, i.e., a so-called “quadruple” or “quad” arrangement, having a length of approximately 160 feet. Other configurations are also possible, e.g., pipe sections comprised of three pipe lengths (“triples”) or two pipe lengths (“doubles”). Such pipe sections  18  are sometimes generically referred to as “pipe stalks.” As indicated in  FIG. 1A , joining of a pipe section  18  to the existing pipeline  12  using a J-lay technique involves positioning the pipe section  18  in a near vertical position, e.g., positioning the pipe section  18  at an angle  21  (see  FIG. 1B ) of approximately 5-10 degrees relative to a plane perpendicular to the surface  10   a  of the lay-vessel  10 , using a pipe section alignment tower  17 . In some techniques, the pipe section  18  to be attached to the end  12   e  of the pipeline  12  is positioned in the pipe section alignment tower  17  while the tower  17  is in an approximately horizontal position. Thereafter, the tower  17  is raised such that the pipe section  18  is in a near vertical orientation. Ultimately, as depicted in  FIG. 1C , the end  18   e  of the pipe section  18  will be butt-welded to the end  12   e  of the pipeline  12 . A variety of holding and positioning mechanisms may be coupled to the pipe section alignment tower  17  to allow handling and positioning of the pipe section  18  at a desired location. For example, such mechanisms may include fixed or moveable clamping mechanisms to secure the pipe during welding operations and/or during the process of lowering the pipeline  12  into the ocean. As another example, a gimbal control mechanism can be employed to move the pipe section  18  in multiple directions. Illustrative clamping and/or positioning mechanisms  23   a - 23   c  as well as an illustrative gimbal control mechanism  27  are schematically depicted in  FIG. 1A .  
      A typical assembly process for joining the pipe section  18  to the pre-existing pipeline  12  will now be further described with reference to  FIGS. 1B and 1C . As indicated in  FIG. 1C , the ultimate objective is to butt-weld the end  12   e  of the pipeline  12  to the end  18   e  of the pipe section  18 , thereby producing the weld joint  20 . As explained more fully below, this is typically accomplished by performing multiple welding passes to completely fill the weld joint  20 . As indicated in  FIG. 1B , a schematically depicted orbital welding device  28  is used to weld the pipe section  18  to the pipeline  12  at weld joint  20 . The orbital welding device  28  may circumscribe the joint  20  by traveling on the illustrative structure  30  depicted therein.  
      However, prior to completing the weld joint  20 , a great deal of activities are undertaken to properly align the end  18   e  of the pipe section  18  relative to the end  12   e  of the pipeline  12 . The position of the pipeline  12  relative to the surface  10   a  of the lay-vessel  10  is maintained via the use of a plurality of powered pipe slips  26  that clamp and secure the pipeline  12  in the desired location. Thereafter, the pipe section  18  that is to be attached to the pipeline  12  is coarsely positioned relative to the end  12   e  of the pipeline  12  through use of the pipe section alignment tower  17  and the gimbal mechanism  27 . Additionally, aligning the pipe section  18  to the pipeline  12  may involve use of a hydraulically-actuated alignment device  22  that is positioned on the interior of the weld joint  20  prior to performing welding operations. Hydraulic power is supplied to the alignment device  22  via hydraulic supply line  24 . In general, the alignment device  22  will be used to circumferentially align the end  18   e  of the pipe section  18  with the end  12   e  of the pipeline  12  prior to beginning welding operations.  
      After proper alignment is achieved, a root pass may be made on the weld joint  20  followed by the removal of the alignment device  22 . Thereafter, several filling passes may be made with the orbital welding device  28  to complete the weld joint  20 . Using this existing methodology, the weld joint  20  has a thickness that corresponds to the thickness of the pipe lengths used to make the pipeline  12 . Thereafter, the weld joint  20  is allowed to cool and various non-destructive examination (NDE) techniques, e.g., x-ray, may be employed to examine the quality of the resulting weld joint  20 . Then, the pipe slips  26  are released and the newly added pipe section  18  is lowered into the ocean  14 . This process is repeated many times to complete the formation of the pipeline  12 .  
      The above-mentioned process can be very time-consuming and costly. For example, for an illustrative 30-inch diameter pipeline  12 , the various alignment and welding techniques described above may take up to 1-1.5 hours per weld joint  20 . What is desired are products and methodologies that enable the formation of pipeline in a more rapid and cost-effective manner.  
      The present invention is directed to an apparatus and methods for solving, or at least reducing the effects of, some or all of the aforementioned problems.  
     SUMMARY OF INVENTION  
      The present invention is directed to threaded connectors for axial alignment of tubular components, and methods of installing pipe sections employing such connectors. In one illustrative embodiment, the device comprises a first section of pipe comprised of at least one length of pipe, a threaded pin connector coupled to the first section of pipe, a second section of pipe comprised of at least one length of pipe and a threaded box connector coupled to the second section of pipe, the box and pin connectors being threadingly coupled to one another and welded to one another along an exterior grooved circumferential weld joint.  
      In another illustrative embodiment, the device comprises a first section of pipe comprised of a plurality of lengths of pipe wherein adjacent lengths of pipe are butt-welded to one another, a threaded pin connector coupled to the first section of pipe, a second section of pipe comprised of a plurality of lengths of pipe wherein adjacent lengths of pipe are butt-welded to one another, and a threaded box connector coupled to the second section of pipe, the box and pin connectors being threadingly coupled to one another and welded to one another along an exterior grooved circumferential weld joint, wherein a sealing interface exists between an exterior sealing surface of the pin connector and an interior sealing surface of the box connector.  
      In yet another illustrative embodiment, the device comprises a first section of pipe comprised of at least one length of pipe, a threaded box connector coupled to a first end of the first section of pipe and a threaded pin connector coupled to a second end of the first section of pipe, wherein an end surface on the pin connector is adapted to define a portion of an external grooved circumferential weld joint between the pin connector and a mating box connector on a second section of pipe comprised of at least one length of pipe when the pin connector and the mating box connector on the second section of pipe are threadingly coupled to one another.  
      In a further illustrative embodiment, the device comprises a first section of pipe comprised of a plurality of lengths of pipe wherein adjacent lengths of pipe are butt-welded to one another, a threaded box connector coupled to a first end of the first section of pipe and a threaded pin connector coupled to a second end of the first section of pipe, the threaded pin connector having an exterior sealing surface and an end surface on the pin connector that is adapted to define a portion of an external grooved circumferential weld joint between the pin connector and a mating box connector on a second section of pipe comprised of at least one length of pipe when the pin connector and the mating box connector on the second section of pipe are threadingly coupled to one another, the mating box connector further comprising an internal sealing surface that is adapted to sealingly engage the exterior sealing surface on the pin connector when the pin connector and the mating box connector are threadingly coupled to one another.  
      In one illustrative embodiment, the method comprises forming a pipeline, an end of the pipeline having a threaded connector, providing a pipe section comprised of at least one length of pipe, the pipe section having threaded connectors on each end of the pipe section, threadingly coupling one of the threaded connectors on the pipe section to the threaded connector on the end of the pipeline and welding the threaded connector on the pipe section to the threaded connector on the end of the previously formed pipeline along an exterior circumferential weld joint. In further embodiments, the step of threadingly coupling one of the connectors on the pipe section to the threaded connector on the end of the pipeline establishes a sealing interface by providing an interference fit between a sealing surface on the connector on the pipe section and a sealing surface on the connector on the end of the pipeline. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
      The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements.  
       FIGS. 1A-1C  depict illustrative examples of a prior art J-lay technique for forming undersea pipelines.  
       FIG. 2  is an illustrative pipe section having threaded connectors in accordance with one illustrative embodiment of the present invention formed thereon.  
       FIG. 3  is a depiction of a mated connector in accordance with one illustrative embodiment of the present invention.  
       FIGS. 4A-4D  are enlarged views of one illustrative embodiment of a threaded connector in accordance with the present invention.  
       FIGS. 5A and 5B  depict installation of an illustrative pipeline in accordance with one illustrative embodiment of the present invention. 
    
    
      While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.  
     DETAILED DESCRIPTION  
      Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers” specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.  
      The present invention will now be described with reference to the attached figures. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.  
      In general, the present invention is directed to threaded connectors for axial alignment of tubular components, and methods of installing pipe sections employing such connectors. As will be recognized by those skilled in the art after a complete reading of the present application, the present invention may be employed for a variety of techniques and purposes. In one particular example, the present invention may be employed in the context of forming sub-surface and surface pipelines and transmission lines. Even more specifically, any of a variety of known techniques for forming pipelines may be employed with the present invention, e.g., J-lay techniques, S-lay techniques, etc. Thus, the present invention should not be considered as limited to the formation of surface or sub-surface pipelines, or to any particular technique for forming pipelines, unless such limitations are expressly set forth in the appended claims.  
       FIG. 2  is a depiction of an illustrative pipe section  50  in accordance with one illustrative embodiment of the present invention. As indicated therein, the pipe section  50  is comprised of four individual pipe lengths  52   a ,  52   b ,  52   c  and  52   d  and a pin connector (male connector)  54   p  and a box connector (female connector)  54   b . In the depicted embodiment, the individual pipe lengths  52   a - 52   d  are coupled to adjacent pipe lengths via butt-welds  56 . Similarly, the pin connector  54   p  and box connector  54   b  are coupled to adjacent pipe lengths via butt-welds  56 . The pin connector  54   p  and box connector  54   b  are adapted to be threadingly coupled to a box connector and pin connector, respectively, that may be positioned on another pipe section  50 .  
      In general, the pipe section  50  may be assembled in a land-based factory prior to the being transported to the pipeline installation site. It should be understood that the pipe section  50  depicted in  FIG. 2  is illustrative in nature as it relates to the number of individual pipe lengths  52  that comprise the pipe section  50 . In the depicted embodiment, there are four illustrative pipe lengths  52   a - 52   d  (a so-called “quad” arrangement). However, the present invention may be employed in cases where a different number of pipe lengths are used to make up the pipe section  50 . For example, the present invention may be employed where only a single pipe length is used, i.e., the pin connector  54   p  and box connector  54   b  are coupled to a single length of pipe (having an illustrative length of approximately 40 feet), or where two or three lengths of pipe are coupled together (so-called doubles or triples, respectively) to make up the pipe section  50 . Thus, the present invention should not be considered as limited to use with any particular number of pipe lengths that make up the pipe section  50  unless such limitations are expressly set forth in the appended claims.  
       FIG. 3  is a partial, cross-sectional perspective view of a mated pin connector  54   p  and box connector  54   b , which of which are coupled to respective pipe sections  50 . As shown therein, the pin connector  54   p  and box connector  54   b  are threadingly engaged to one another by a plurality of threads  58 . Additionally, in one illustrative embodiment, a sealing interface  60  (described more fully below) is provided between the pin connector  54   p  and the box connector  54   b . The pin connector  54   p  and box connector  54   b  are also welded together at weld joint  70 . In general, the weld joint  70  is a circumferential weld that extends around the entire circumference of the mated connectors. However, in some cases, the weld may not extend around the entire circumference of the mated connectors.  
       FIGS. 4A-4D  depict enlarged, cross-sectional views of a mated pin connector  54   p  and box connector  54   b . As indicated therein, the sealing interface  60  is established between an exterior sealing surface  61   p  on the pin connector  54   p  and an interior sealing surface  61   b  on the box connector  54   b . Typically, the sealing interface  60  is established by providing an interference fit between the surfaces  61   p  and  61   b . The sealing interface  60  provides a liquid-tight and gas-tight seal for fluids flowing through the pipeline.  
      The threaded connection  58  between the pin connector  54   p  and the box connector  54   b  may be comprised of a variety of different thread configurations  80 . In one illustrative embodiment, the threaded connection  58  is comprised of wedge-shaped, dovetailed thread forms  80  with a continuously varying flank-to-flank width. The illustrative wedge-shaped threads are provided to ensure that as the connectors  54   p  and  54   b  are being mated together, the joint becomes tighter and tighter as the connection is made.  
      When the connectors  54   p  and  54   b  are mated together, a grooved weld joint  70  is created between the pin connector  54   p  and the box connector  54   b . More specifically, a grooved weld joint  70  is defined between an end surface  71  of the box connector  54   b  and a surface  72  of the pin connector  54   p . In one particular embodiment, the surface  72  is a side surface formed on a shoulder  55  of the pin connector  54   p . In the illustrative example depicted in  FIGS. 4A-4D , the diameter of the outer surface of the shoulder  55  is approximately the same as the diameter of the outer surface of the box connector  54   b  at the weld joint  70 . In the depicted embodiment, the weld joint  70  is a low profile J-bevel weld joint  70 . However, the configuration of the weld joint  70  may be varied if desired. For example, the weld joint  70  may be a single- or double-beveled grooved weld joint  70 . The illustrative grooved weld joint  70  provides additional strength between the connectors  54   p ,  54   b  relative to other types of weld joints, e.g., a fillet weld joint. Filling of the weld joint  70  provides mechanical connection between the box connector  54   b  and the pin connector  54   p  and provides a redundant, or secondary, seal with respect to the fluids flowing within the pipeline  12 . In one illustrative embodiment of the present invention, the weld joint  70  may be filled by performing a single submerged arc welding process.  
      Additionally, due to the configuration of the connectors  54   p ,  54   b , attachment areas  75  (see  FIG. 4A ) are provided on the connectors  54   p ,  54   b . Such attachment areas  75  may be used for a variety of purposes during handling of the pipe section  50  and/or during the assembly of the pipeline  12 . For example, various lifting ropes or chains may be attached to the pipe section  50  at one of the attachment areas  75 . The size and configuration of the attachment areas  75  may vary. In one illustrative embodiment, each of the attachment areas  75  has an axial length of approximately 3 inches and a radial depth of approximately 0.625 inches.  
      Use of the present invention in the context of forming a subsea pipeline using a J-lay technique will now be described with reference to  FIGS. 5A and 5B . However, as indicated previously, the present invention should not be considered as limited to such an application, unless such limitations are expressly set forth in the appended claims. For example, the present invention may also be employed in connection with forming a land-based or surface pipeline. As depicted in  FIG. 5A , a plurality of pipe sections  50  comprised of the pin and box connectors  54   p ,  54   b  are positioned on the lay-vessel  10 . The previously formed pipeline  12  has an end with a threaded connector, e.g., a box connector  54   b  or  a  pin connector  54   p , positioned thereon. In the illustrative embodiment depicted in  FIG. 5A , an illustrative box connector  54   b  is depicted on the end of the pipeline  12 . In this illustrative example, the box connector  54   b  on the previously installed pipeline  12  is positioned above the surface  10   a  of the lay-vessel  10  and secured in position by the pipe slips  26 . An illustrative pipe section  50  in accordance with the present invention is positioned in the pipe section alignment tower  17 . The pipe section  50  is depicted in the position where the pin connector  54   p  of the pipe section  50  may now be mated with the box connector  54   b  of the previously formed pipeline  12 . Of course, the situation could be reversed if desired, i.e., the end of pipeline  12  could have a pin connector  54   p  and the box connector  54   b  of pipe section  50  could be threadingly coupled to the pin connector  54   p  on the previously formed pipeline  12 . As with the prior art technique, the pipe section alignment tower  17 , various positioning and clamping mechanisms, as well as a gimbal positioning mechanism, may be employed to coarsely position the pipe section  50  prior to threadingly engaging the pin  54   p  of the pipe section  50  with the box  54   b  of the pre-existing pipeline  12 .  
      The lay-vessel  10  also includes a means for rotating the pipe section  50  to thereby threadingly engage the pin connector  54   p  with the box connector  54   b . Any of a variety of known techniques and structures may be employed for rotating the pipe section  50 . For example, a schematically depicted power tong  57 , such as that described in U.S. Pat. No. 6,330,911 B1, may be provided to provide the desired rotational movement to the pipe section  50 . U.S. Pat. No. 6,330,911 B1 is hereby incorporated by reference in its entirety. Alternatively, a schematically depicted top drive unit  59  may be employed to provide the desired rotational movement to the pipe section  50 . One illustrative embodiment of such a top drive mechanism  59  that may be employed is disclosed in U.S. Pat. No. 6,622,796 B1, which is hereby incorporated by reference in its entirety. Of course, slight modifications may be necessary to devices depicted in the above-described patents for use with the present invention. However, such modifications are well within the level of skill in the art.  
      The structures and methodologies described herein provide many advantages relative to the prior art. For example, in employing the present invention, the alignment device  22  depicted in  FIG. 1B  is not required. Additionally, in one illustrative embodiment, the weld joint  70  of the present invention has a depth that is typically approximately 20-30%, and in a more specific embodiment, approximately 25%, of the wall thickness of the pipe lengths used to make up the pipe section  50 . As a result, the welding process used to fill the weld joint  70  may be performed much more quickly when compared to the prior art technique wherein individual pipe lengths or sections are butt-welded to one another. For example, in the case of an illustrative 30-inch diameter pipeline, butt-welding the individual pipe lengths or sections to one another in accordance with the prior art techniques disclosed above typically required approximately 1-1.5 hours; whereas, filling the weld joint  70  in accordance with the present invention may be performed in approximately 15-20 minutes. Obviously, such time savings greatly increase productivity and reduce costs as it relates to creating and laying the pipeline  12 .  
      The present invention is directed to threaded connectors for axial alignment of tubular components, and methods of installing pipe sections employing such connectors. In one illustrative embodiment, the device comprises a first section of pipe comprised of at least one length of pipe, a threaded pin connector coupled to the first section of pipe, a second section of pipe comprised of at least one length of pipe and a threaded box connector coupled to the second section of pipe, the box and pin connectors being threadingly coupled to one another and welded to one another along an exterior grooved circumferential weld joint.  
      In another illustrative embodiment, the device comprises a first section of pipe comprised of a plurality of lengths of pipe wherein adjacent lengths of pipe are butt-welded to one another, a threaded pin connector coupled to the first section of pipe, a second section of pipe comprised of a plurality of lengths of pipe wherein adjacent lengths of pipe are butt-welded to one another, and a threaded box connector coupled to the second section of pipe, the box and pin connectors being threadingly coupled to one another and welded to one another along an exterior grooved circumferential weld joint, wherein a sealing interface exists between an exterior sealing surface of the pin connector and an interior sealing surface of the box connector.  
      In yet another illustrative embodiment, the device comprises a first section of pipe comprised of at least one length of pipe, a threaded box connector coupled to a first end of the first section of pipe and a threaded pin connector coupled to a second end of the first section of pipe, wherein an end surface on the pin connector is adapted to define a portion of an external grooved circumferential weld joint between the pin connector and a mating box connector on a second section of pipe comprised of at least one length of pipe when the pin connector and the mating box connector on the second section of pipe are threadingly coupled to one another.  
      In a further illustrative embodiment, the device comprises a first section of pipe comprised of a plurality of lengths of pipe wherein adjacent lengths of pipe are butt-welded to one another, a threaded box connector coupled to a first end of the first section of pipe and a threaded pin connector coupled to a second end of the first section of pipe, the threaded pin connector having an exterior sealing surface and an end surface on the pin connector that is adapted to define a portion of an external grooved circumferential weld joint between the pin connector and a mating box connector on a second section of pipe comprised of at least one length of pipe when the pin connector and the mating box connector on the second section of pipe are threadingly coupled to one another, the mating box connector further comprising an internal sealing surface that is adapted to sealingly engage the exterior sealing surface on the pin connector when the pin connector and the mating box connector are threadingly coupled to one another.  
      In one illustrative embodiment, the method comprises forming a pipeline, an end of the pipeline having a threaded connector, providing a pipe section comprised of at least one length of pipe, the pipe section having threaded connectors on each end of the pipe section, threadingly coupling one of the threaded connectors on the pipe section to the threaded connector on the end of the pipeline and welding the threaded connector on the pipe section to the threaded connector on the end of the previously formed pipeline along an exterior circumferential weld joint. In further embodiments, the step of threadingly coupling one of the connectors on the pipe section to the threaded connector on the end of the pipeline establishes a sealing interface by providing an interference fit between a sealing surface on the connector on the pipe section and a sealing surface on the connector on the end of the pipeline.  
      The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. For example, the process steps set forth above may be performed in a different order. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.