Abstract:
For use in closing a cylindrical passageway through a working member in which the passageway is defined in part by a reduced diameter internal circumferential sealing surface and an internal locking groove, a completion plug having a plug body with a cylindrical external surface receivable within the cylindrical passageway of the working member and having an external circumferential sealing surface dimensioned to radially compressibly engage the working member internal circumferential sealing surface. The plug body has on its cylindrical surface an external locking groove. A locking ring is received in the working member internal locking groove and simultaneously in the plug body external locking groove and serves to lock the plug body within the working member.

Description:
REFERENCE TO PENDING APPLICATIONS 
   This application is not based upon any pending domestic or international patent applications. 
   REFERENCE TO MICROFICHE APPENDIX 
   This application is not referenced in any microfiche appendix. 
   FIELD OF THE INVENTION 
   This invention relates to an irremovable, rotation-free installation, non-galling, metal-to-metal completion plug for closing a cylindrical passageway. 
   BACKGROUND OF THE INVENTION 
   It is frequently necessary to close an opening in a tubular member either temporarily, semi-permanently or, in the case of the present invention, permanently. That is, to close an opening when a valve is not required and is not desirable. One example of the utilization of a completion plug arises when a hot tap is made into a pipeline or vessel through a fitting connected to the pipeline or vessel. In the typical hot tapping application as utilized in the petroleum, chemical, refinery and other similar industries, a fitting, usually in the form of a flange, is welded on the exterior of a pipe that has flowing gas or liquid under pressure. A valve is then secured to the flange and a hot tapping machine is secured to the valve. By use of specialized equipment, a hole can then be drilled through the wall of the pipe while gas or liquid continues to flow through it. This provides access to the interior of the pipe, such as for inserting equipment to temporary block flow through the pipe while repairs are being made. After repairs are complete, the equipment is removed and the opening that provides communication to the interior of the pipe needs to be closed. In some instances, as above indicated, the closure is made in a way that at a future date access can again be obtained through the fitting to the interior of the pipe. In the present case a completion plug is provided that permanently closes the opening. In addition, most known completion plugs make use of elastomers, such as rubber or plastics, to achieve leak proof sealing. The present invention, in contrast, provides heat resisting, metal-to-metal sealing. 
   For background information relating to completion plugs, reference may be had to the following previously issued United States patents. 
   
     
       
             
             
             
           
         
             
                 
             
             
               Patent 
                 
                 
             
             
               Number 
               Inventor 
               Title 
             
             
                 
             
           
           
             
               428,422 
               Skinner 
               Casing Head 
             
             
               1,810,621 
               Parks 
               Valve Mechanism 
             
             
               2,085,119 
               Penick et al. 
               Seal Off Tool 
             
             
               2,134,311 
               Minor et al. 
               Method and Apparatus For Suspending 
             
             
                 
                 
               and Sealing Well Casings 
             
             
               2,771,096 
               Ver Nooy 
               Fluid Tight Closure 
             
             
               2,988,111 
               Ver Nooy 
               Fluid Tight Closure 
             
             
               3,074,591 
               Raver 
               Pressure Closure 
             
             
               3,155,116 
               Ver Nooy 
               Apparatus For Closing Side Openings 
             
             
                 
                 
               Into Pipelines 
             
             
               3,289,765 
               Hynes 
               Method and Apparatus For Completing 
             
             
                 
                 
               Wells 
             
             
               3,405,763 
               Pitts et al. 
               Well Completion Apparatus and Method 
             
             
               3,766,947 
               Osburn 
               Fluid Tight Closure 
             
             
               4,058,142 
               Rankin 
               Pipeline Fitting 
             
             
               4,144,909 
               Harrison 
               Apparatus For Closing Side Openings 
             
             
                 
                 
               Into Pipelines 
             
             
               4,326,587 
               Gauthier et al. 
               Casing Hanger and Stabilizer 
             
             
                 
                 
               Apparatus and Method 
             
             
               4,387,740 
               Vanzant 
               Cam-Flange 
             
             
               4,466,550 
               Sullivan 
               Closure For A Cylindrical Opening 
             
             
                 
                 
               Having Improved Venting Means 
             
             
               4,609,209 
               Ralls 
               Precise Alignment Adapter Flange 
             
             
               4,693,278 
               Wilson et al. 
               Safety Closure Member 
             
             
               4,749,047 
               Taylor 
               Annular Wellhead Seal 
             
             
               4,886,121 
               Demny et al. 
               Universal Flexbowl Wellhead 
             
             
                 
                 
               and Well Completion Method 
             
             
               5,114,158 
               Le 
               Packing Assembly For Oilfield 
             
             
                 
                 
               Equipment and Method 
             
             
               5,209,521 
               Osborne 
               Expanding Load Shoulder 
             
             
               5,327,965 
               Stephan et al. 
               Wellhead Completion System 
             
             
               5,450,765 
               Stover 
               Apparatus For Providing Signal 
             
             
                 
                 
               Communication Between The Interior and 
             
             
                 
                 
               Exterior Of A Pipeline 
             
             
               5,456,320 
               Baker 
               Casing Seal and Spool For Use In 
             
             
                 
                 
               Fracturing Wells 
             
             
               5,490,565 
               Baker 
               Casing Seal and Spool For Use In 
             
             
                 
                 
               Fracturing Wells 
             
             
               5,975,142 
               Wilson 
               Removable Closure System 
             
             
               5,984,008 
               Lang et al. 
               Installable Load Shoulder For Use In A 
             
             
                 
                 
               Wellhead To Support A Tubing Hanger 
             
             
               6,116,285 
               Wilson 
               Removable Threaded Plug 
             
             
               6,286,553 
               Morgan 
               Removable Closure System 
             
             
                 
             
           
        
       
     
   
   BRIEF SUMMARY OF THE INVENTION 
   This invention provides a closure member that is commonly referred to as a completion plug. A completion plug of the type characterized by the present invention provides means for closing a cylindrical opening or passageway. In a typical application of the invention, the completion plug is used to close the passageway through a flange member, that is, a tubular member that has an integral, radially extending flange portion that is readily adaptable for the attachment of other structural or piping devices. A flange member as used in the present invention has an inner end and an outer end with a passageway defined by a cylindrical surface having a first internal diameter adjacent the inner end, an intermediate cylindrical surface of slightly increased diameter and a third cylindrical surface of increased internal diameter, the third cylindrical surface communicating with the flange outer end. Formed in the third cylindrical surface that is contiguous with, or at least adjacent, the flange outer end is an increased internal diameter circumferential groove. 
   The completion plug of this invention is formed of three basic elements, that is, a plug body, a completion tool that is used in the installation of the plug body and an insertion member that is separately manufactured but is permanently secured to the completion tool. The plug body is a cylindrical member having an inner end and an outer end. On the cylindrical surface of the plug body adjacent the inner end is a sealing surface. In the preferred and illustrated arrangement the sealing surface includes circumferential beads of slightly increased external diameter. These circumferential beads contact the interior cylindrical intermediate surface of the flange when the completion plug is installed in position within the flange. 
   Formed on the external cylindrical surface of the plug body adjacent the outer end is a circumferential slot that receives therein a lock ring. The lock ring is manufactured such as to have a slight radial expansion characteristic so that it must be externally compressed to be confined within the external circumferential slot of the plug body. 
   The plug body is further defined by a concentric, integral, short-length central post that has a circumferential recess on its external surface. 
   The plug body is carried into position within the cylindrical opening in the flange fitting by means of the completion tool that includes an inner tubular portion of internal diameter dimensioned to receive the central post of the plug body. Further the completion tool includes an outer circumferential lip portion that has an internal diameter slightly greater than the external diameter of the plug body at the plug body outer end. 
   A tubular insertion member is received within the tubular opening of the completion tool and is telescopically secured to the completion tool. The insertion member has an internal surface adjacent the outer end thereof that slidably receives the plug central post. Retention balls are retained by the insertion tool that extend inwardly into the circumferential recess in the central post of the plug body so that the insertion tool and thereby the completion tool itself are removably secured to the plug body. 
   The completion tool is telescopically secured to the insertion member for use in inserting the plug body into the cylindrical passageway of a flange fitting. When secured to the plug body the completion tool lip portion surrounds the lock ring that is compressed within the plug body outer circumferential slot. 
   The completion plug is installed by moving the assembly of the completion plug, completion tool and insertion member into the flange fitting passageway. The insertion tool circumferential lip portion engages the upper end of the flange fitting, limiting further downward movement of the insertion tool relative to the flange fitting. However, additional downward force on the insertion member pushes the plug body downwardly past the completion tool lip portion. This allows the lock ring to expand outwardly and into the internal circumferential groove formed in the flange fitting. With the lock ring partially within the inner circumferential groove of the flange fitting and partially within the outer circumferential slot of the plug body, the plug body is locked in position within the flange fitting. The plug body circumferential sealing surface is then in metal-to-metal contact with the intermediate cylindrical surface of the flange fitting passageway providing a leak proof, heat resistant metal-to-metal seal thereby closing fluid flow through the flange fitting passageway. 
   After the plug body has been pushed into position so that the lock ring expands outwardly into the circumferential groove of the flange fitting, the direction of force applied to the insertion member is reversed so the insertion member is moved upwardly with respect to the plug body which is now locked into position within the flange fitting. Upward displacement of the insertion member carries with it the completion tool so that only the plug body remains within the flange fitting passageway. Thereafter, as a safety measure, a blind flange can be secured to the flange fitting upper end. 
   The completion plug disclosed herein is referred to as a “High Temperature” Completion Plug. This title has been selected since it alludes to an important characteristic of the plug, that is, its metal-to-metal seal that does not rely on elastomeric materials. The absence of elastomers makes the completion plug particularly useful for high temperature applications but it is by no means limited to such applications and can be used to close flow irrespective of the temperature of the fluid. 
   A better understanding of the invention will be obtained from the following detailed description of the preferred embodiments and claims, taken in conjunction with the attached drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an elevational cross-sectional view of an assembly for use in plugging a pipe. The assembly includes a flange fitting having a cylindrical passageway therethrough. Affixed to the flange fitting is the lower portion of apparatus by which the pipe has been accessed for performing a plugging operation. An extendable shaft has affixed to a lower end thereof a high temperature completion plug assembly that is used to close the passageway through the flange fitting. The present invention concerns this high temperature completion plug assembly. 
       FIG. 2  is an external view of a completion plug assembly that incorporates the principles of this invention. 
       FIG. 3  is a cross-sectional view of the completion plug assembly as taken along the line  3 - 3  of  FIG. 2 . 
       FIG. 4  is an external view of the completion tool and insertion member that are used for installation of the completion plug within a cylindrical opening, such as the passageway of a flange fitting as shown in  FIG. 1 . 
       FIG. 5  is a cross-sectional view of the completion plug installation tool and insertion member of  FIG. 4 , taken along the line  5 - 5  of  FIG. 4 . 
       FIG. 6  illustrates a flange fitting, shown cutaway, with a completion plug of this invention installed within the cylindrical passageway to thereby sealably close the passageway in a metal-to-metal relationship. Such metal-to-metal relationship provides a high temperature closure of the flange fitting by eliminating the use of elastomeric or other non-metallic sealing elements that can fail in case of a fire or when high temperatures are otherwise encountered. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   It is to be understood that the invention that is now to be described is not limited in its application to the details of the construction and arrangement of the parts illustrated in the accompanying drawings. The invention is capable of other embodiments and of being practiced or carried out in a variety of ways. The phraseology and terminology employed herein are for purposes of description and not limitation. 
   Elements illustrated in the drawings are identified by the following numbers:
       10  Pipe     12  Collar     14  Collar     16       18  Upper containment portion     20  Bottom opening     22  Tubular extension     24  Closure head     26  Cylindrical opening     28  Bottom cylindrical opening     30  Flange fitting     32  Passageway through flange  30       34  Exposed end of pipe  10       36  Exposed end of pipe  10       38  Completion plug assembly     40  Top surface of flange  30       42  Valve bottom flange     44  Valve     46  Top valve flange     48  Bottom flange     50  Hydraulic cylinder     52  Vertical passageway     54  Valve closure member     56  Hand wheel     58  Piston rod     60  Plug body     62  Completion plug     64  Insertion member     66  Lower end     68  Upper end     70  Cylindrical surface     72  Central post portion     74  Annular recess     76  Groove     78  External circumferential sealing surface     80  Circumferential bead surfaces     82  Annular recess     84  Base portion of the central post     86  Top portion of the central post     88  Circumferential groove     90  Tubular portion     92  Internal diameter     94  Cap portion     96  Bonnet portion     98  Lower circumferential edge     100  Upper part of tubular portion  90       102  Threaded openings     104  Spring plungers     106  Inner end     108  External surface     110  First circumferential notch     112  Second circumferential notch     114  Internal threads     116  Internal diameter     118  Radial openings     120  Sphere     122  Lock ring     124  Internal circumferential sealing surface     126  Internal groove in flange  30       128  External threads     130  Increased internal diameter portion of  90     

   Before describing the details of the completion plug assembly of this invention, a typical environment in which a completion plug is used will be explained making reference to  FIG. 1 . This figure shows a pipe or pipeline  10  and affixed to it portions of a closure system by which flow through the pipe can be terminated temporarily for purposes of repair or maintenance. Welded to the exterior of pipe  10  are collars  12  and  14 . After the collars are welded in position around the pipe, a containment housing is formed by welding to the collars a lower containment portion  16  and an upper containment portion  18 . The lower containment portion  16  has a bottom opening  20  that receives a tubular extension  22  which in turn receives a closure head  24 . Upper containment portion  18  has an upper cylindrical opening  26  that has welded to it the bottom cylindrical opening  28  of a flange fitting  30 . 
   All of the elements enumerated to this point are welded to each other to form a containment housing surrounding a length of pipe  10 . Flange fitting  30  has a passageway  32  through which tools may be moved for operating on the portion of pipe  10  within the containment housing. By means of a circular saw (not shown), a length of the pipe  10  is cut and removed leaving exposed pipe ends  34  and  36 . Apparatus (not shown) can now be inserted through the passageway  32  in flange fitting  30  to cap off the ends  34  and  36  of pipe  10  and thereby close fluid flow. After repair or maintenance has been done, the mechanism for capping off the ends of the pipe are removed and it then becomes necessary to provide a permanent closure of the containment housing. Specifically, to complete the job of temporarily terminating fluid flow through pipe  10 , the passageway  32  in flange fitting  30  must be closed. The invention herein provides a system of achieving permanent, high temperature closure of passageway  32  by means of a completion plug assembly generally indicated by the numeral  38 . 
   Before describing the details of completion plug assembly  38  and flange fitting  30 , further reference to  FIG. 1  shows systems by which completion plug assembly  38  can be installed into flange fitting  30 . Secured to the top surface  40  of flange fitting  30  is a valve bottom flange  42  which is a lower portion of a valve generally indicated by the numeral  44 . Valve  44  has a top flange  46  which receives the bottom flange  48  of a hydraulic cylinder  50 . Valve  44  has a vertical passageway  52  therethrough that is of internal diameter equal to or greater than the passageway  32  in flange  30 . Opening  52  in valve  44  may be closed by a valve closure member  54  that is moved into and out of closed position by a hand wheel  56 . Valve  44  makes it possible to move tools into and out of the containment housing that has been formed around pipe  10  to perform operations such as to sever the pipe to leave exposed ends  34  and  36  and to insert into the containment housing equipment (not shown) by which the flow through pipe  10  is completely closed. As previously stated, after all operations necessary within the containment housing have been completed it is then necessary to close passageway  32  in flange fitting  30  and this is the function of the completion plug assembly  38 . 
   There is shown, extending from cylinder  50 , a piston rod  58  which is attached to a piston (not shown) by which completion plug assembly  38  is moved into position to close passageway  32  through flange fitting  30 . 
   The completion plug assembly which is the essence of this invention will now be described with reference to  FIGS. 2 through 5 .  FIG. 2  is an external view of the completion plug assembly  38  while  FIG. 3  is a cross-sectional view. The completion plug assembly consists essentially of three basic metal components. These are, a plug body  60 , a completion plug  62  and an insertion member  64 . Plug body  60  has a lower end  66  and an upper end  68 . The plug body has a cylindrical external surface  70  and further includes an integral, upstanding central post portion  72  leaving an annular recess  74 . Formed in the external cylindrical surface  70  of the plug body is a circumferential external groove  76 . 
   Integrally formed as a lower portion of plug body  60  is a external circumferential sealing surface generally indicated by the numeral  78 . Sealing surface  78  is preferably surface hardened to reduce galling. In the illustrated and preferred embodiment of circumferential sealing surface  78  a plurality of circumferential radially extending bead surfaces  80  are formed. In the illustrated embodiment there are two spaced apart circumferential bead surfaces  80 , however, only a single circumferential bead surface may be used or a plurality of two or more may be employed. Two spaced apart circumferential beads  80  as illustrated are considered an optimal sealing surface for the completion plug. 
   There is formed in the lower end  66  of plug member  60  an annular recess  82  that provides a slight degree of compressive flexibility to the circumferential sealing surface  78 . This configuration provides a compressive metal-to-metal seal of the plug as it is contained within flange fitting  30 . 
   The central post  72  of plug body  60  has a lower, larger diameter, base portion  84 , and an upper reduced external diameter top portion  86 . Formed on the central post top portion  86  is a circumferential groove  88 . 
   Positioned on plug body  60  is the completion plug  62  which has an internal tubular portion  90  having an internal diameter  92  that telescopically extends over plug body central post base portion  84 . A radially extending cap portion  94  has a downwardly extending bonnet portion  96  that terminates with a lower circumferential edge  98 . The upper part  100  of tubular portion  90  is of increased thickness and has opposed threaded openings  102 , each of which receives a spring plunger  104  having an inner end  106 . 
   Insertion member  64  is tubular with a cylindrical surface  108  that has a first circumferential notch  110  and a second circumferential notch  112 . The upper interior end of the insertion member has internal threads  114 . 
   The lower portion of the tubular insertion member  64  is of internal diameter  116  to telescopically fit over the top portion  86  of central post  72  of plug body  60 . Radial opening  118  extends through the wall of the lower tubular portion of the insertion member and receives spheres  120  that are of a diameter greater than the thickness of the tubular wall of the lower portion of the insertion tool so that the spheres extend within circumferential groove  88  formed in the top portion  86  of the plug body. 
   Received within circumferential groove  76  formed in the exterior surface  70  of plug body  60  is a split lock ring  122  that is formed so that it has a normal exterior diameter greater than the external diameter in the groove in which it rests as seen in  FIG. 3 . Therefore, the lock ring  122  is in a compressed state as seen in  FIG. 3  and held in such compressed state within groove  76  by the lip portion  96  of the completion tool. 
   Reference will now be made to  FIG. 6  which illustrates a cross-sectional perspective view of flange fitting  30  with plug body  60  installed therein. Flange fitting  30  has, as previously described, a passageway  32  therethrough. A lower portion of passageway  32  forms a circumferential sealing surface  124  and is of reduced internal diameter relative to the base passageway  32  in flange  30 . In addition, within flange passageway  32  is an increased diameter groove  126  that is dimensionally configured substantially like the external circumferential groove  76  in plug body  60 . 
   The method of installation of plug body  60  into flange fitting  30  to assume the position and condition as shown in  FIG. 6  will now be described. As seen in  FIG. 1 , piston rod  58  is employed to insert plug body  60  into flange fitting  30 , then remove completion plug  62  and insertion member  64  after the plug body installation is achieved. The lower end of piston rod  58  is externally threaded at  128  and threadably engages the internal threads  114  at the top end of insertion member  64  to interconnect piston rod  58  and completion plug assembly  38 . As the assembly is forced downwardly into flange fitting  30 , the lower end of the plug body enters into passageway  32 . The assembly continues to move downward until the lower circumferential edge  98  of completion plug  62  engages the top surface  40  of flange fitting  30 . The external diameter of bonnet portion  96  is greater than the internal diameter of passageway  32  in the flange and therefore further downward movement of completion plug  62  is terminated. However, with increased downward force of piston rod  58 , insertion member  64  carrying with it plug body  60  continues to move downward. This is achieved by application of sufficient force such that the inner ends  106  of spring plungers  104  are retracted sufficiently to permit insertion member  64  to pass downwardly past spring plungers  104 . As this action takes place the plug body is forced downwardly with respect to completion plug  62  so that the lock ring  122  passes beyond the lower end of the lower circumferential edge  98  of bonnet portion  96  of the insertion tool. This allows lock ring  122  to expand radially outwardly and into groove  126  in flange member  30 . The depth of groove  126  is less than the thickness of lock ring  122  so the lock ring extends partially into groove  126  in flange fitting  30  and partially within groove  76  in plug body  60 . When lock ring  122  has been installed as shown in  FIG. 6 , the completion plug  62  and insertion member  64  are in the position with respect to each other as seen in  FIGS. 4 and 5 . In this position spheres  120  are permitted to radially expand outward by an increased internal diameter portion  130  of the completion tool tubular portion  90 . When this occurs, the insertion tool  64  and completion plug  62  are free to be extracted upwardly from plug body  60 .  FIG. 1  shows the condition in which the plug body  60  has been installed within the passageway through the flange fitting  30  and the completion plug  62  and insertion member  64  can freely be removed upwardly to pass through valve  44 . Thereafter bolts holding lower flange  42  of valve  44  to flange fitting  30  may be removed. The opening through flange fitting  30  is sealed in a metal-to-metal heat resisting fashion. Typically a blind flange or other closure member (not shown) is bolted to the top surface  40  of flange fitting  30  as a safety precaution. Thus, the plug body has been inserted into the flange fitting  30  with the circumferential sealing surface  78  as characterized by circumferential beads  80  in metal-to-metal sealing contact with the internal circumferential sealing surface  124  of flange fitting  30 . 
   The completion plug as has been described has three important features. First, as stated above, the completion plug attains metal-to-metal closure of the passageway through the flange fitting. Second, the sealing surface  78  of plug body  60  is surface hardened to reduce galling. Third, the assembly of the plug body into the flange fitting does not require any rotation, that is, no part of the sealing operation requires a threading or other rotational action. 
   While the invention has been described with a certain degree of particularity, it is manifest that many changes may be made in the details of construction and the arrangement of components without departing from the spirit and scope of this disclosure. It is understood that the invention is not limited to the embodiments set forth herein for purposes of exemplification, but is to be limited only by the scope of the attached claim or claims, including the full range of equivalency to which each element thereof is entitled.