Abstract:
A theft abating stud and nut assembly is provided for use on flanges of members of a fluid flow conduit, such as oil well production conduits, pipelines, and the like. Tapered smooth outer surface nuts are used with studs which are assembled by placing the studs in tension during assembly on the flanges. A method for such assembly is also disclosed.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to a theft abating combination stud and nut assembly for affixation in openings around flanges on fluid flow conduits, such as oil field well head Christmas trees, refinery conduits, gas production pipe lines, and the like.  
         [0003]     2. Brief Description of the Prior Art  
         [0004]     Oil well Christmas trees are quite common on inland as well as offshore oil and gas wells. These assemblies are securely mounted at the top of the well and provide a number of valves and similar components to permit safe but controlled release of produced hydrocarbon constituents within the well and may be manipulated to close off such production and other fluids for safety or other purposes.  
         [0005]     In some remote locations throughout the world, the Christmas trees on the wells are targets for thieves, who would cannibalize the Christmas trees and sell the valves and other parts on the black market. Typically, since the valving components making up the Christmas tree are secured one to another through housings or conduits having metallic outwardly extending flange members, such flange members are typically secured one to another using a series of threaded nut and bolt assemblies. There is a slight gap between the flange members, even when they are tightly secured one to another, because of a seal face around the interior of the flange, which actually seals the flanged members together, to avoid escape of producing fluids, or the like.  
         [0006]      FIG. 2  is an illustration of a typical prior art flange engagement system A. The system A consist of upper and lower flange members B and C which have a series of radically and vertically disposed bores B- 1  and C- 1  ( FIGS. 5 and 6 ) there through for aligning introduction of conventionally threaded studs E. The studs E are secured to the flanges B, C by means of first and second companionly threaded nut members F. The nut members each have a series of angled face members G for application of a field wrench (not shown) to apply torque to close a gap age between respective interfaces of the flange members B, C.  
         [0007]     As will be appreciated, all that a potential thief need do to remove the flanges B, C one from another, is to place a similar wrench over each of the nuts F and apply an opposing torque to remove the nuts F from the studs E and separate the flange members, thereafter removing whatever valve component is desired to be stolen. The result of this action is not only the loss of the valve component, but the resultant loss of the integrity of the Christmas tree to control the well, as well as the loss of production from the well and, in turn, possible contamination of the surrounding areas with oil and/or gas, and possible pollution of rivers, streams and other waters nearby.  
         [0008]     The above-described problem is equally applicable to fluid flow conduits other than Christmas trees, such as refinery conduits, oil and gas production conduits and pipelines, and any other fluid flow conduit where members are joined together with flange components affixed to one another by conventional nuts and studs.  
         [0009]     The present invention addresses the problems associated with conventional prior art assemblies by providing a combination nut and bolt theft abatement system.  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention is directed to a theft abating combination stud and nut assembly for affixation in openings around first and second flanges of joining members of a fluid flow conduit assembly. The fluid flow conduit assembly may include an oil field Christmas tree, comprised of valves, meters and controls of various sorts, hydrocarbon pipelines, flange assemblies on numerous fluid flow conduits found in refineries and other fluid flow conduit assemblies incorporating flange members which are secured one to another by the use of a plurality of studs and bolts and where it is desirable for safety and or security reasons to assure the securement of the flanges against efforts by thieves or the like to disengage and remove the studs and nuts to disengage the flanges, for whatever may be the objective of the thief, or other unauthorized person.  
         [0011]     A combination stud and nut assembly comprises an elongated stud member, including an external circumferentially defined threading system thereon, and further including first and second ends thereof. The stud member is made of a metal, plastic or other solid component which permits the stud to be placeable into tension during affixation. An outer central section length of the threaded stud member is hardened, preferably to at least from between about 55 and about 65 Rockwell C hardness, with at least a part the central section length being placeable between the first and second flanges upon affixation of the assembly onto the flanges.  
         [0012]     The combination stud and nut assembly further comprises first and second nut members, each having an internal threaded system for companion inter engagement with the threading system along the stud member as the nut members are secured onto the stud member. The nut members each include first and second ends thereon and further include a smooth conically tapered outer surface extending from the first end to the second end.  
         [0013]     In a preferred embodiment, at least one tensioning cavity may be defined on the outer surface of each of the nut members for insertion of an adjusting pin, or the like, for tightening of the nut members onto the stud member as the stud member is placed in tension during the affixation. The tightening of the nut member through use of the adjusting pin is accomplished by placing the stud in tension to slightly elongate the stud within the elastic limits of its composition so that the nut may be moved toward engagement position on the flange member without application of torque to either the stud or nut members. Of course, the invention need not include such alternative preferred embodiment. It is only preferable to provide any means for moving the nut toward the flange as tension is applied to the stud. For further example, epoxy or other similar hex or similarly designed flats could be cast or otherwise secured onto the exterior of the conical nuts, and a wrench applied upon them to move the nut toward the flange during installation. Thereafter, the flats could be broken off or otherwise removed from the exterior of the nuts.  
         [0014]     Alternatively, the flats could be left in place after installation and, if thievery is not undertaken thereafter and the flats removed during theft, the flats could be used to remove the nuts if the flanges are to be disengaged from one another by a legitimate engineer or other authorized personnel.  
         [0015]     Alternatively, the invention could be designed such that no such means are needed and the nut is permitted, for example, to simply gravitate toward the flange during the securement process, as tension is applied to the stud to elongate the stud within the elastic limits of its composition.  
         [0016]     In another preferred embodiment, the stud and nut combination assembly provides for a series of slots defined on the inner face of said flanges, with the slots on the inner face of one of the flanges being vertically alienable with each of the slots on the inner face of the other of the flanges. Metallic bridge means are then insertable within the slots and disposed at least partially across the diameter of the lugs extending between the flanges, to resist sawing or hacking of a length of the stud at a point in between the flanges.  
         [0017]     In yet another preferred embodiment, the flanges provide inner and outer faces and the assembly further comprises a circumferentially extending groove way defined on each of said inner faces of said flanges and outboard of the openings in said flanges. A metallic bridge means is houseable in the groove way for resisting cutting or hacking of the studs during attempted theft.  
         [0018]     The present invention is also directed to a method for theft abatement of flanges joining members of a fluid flow conduit. A combination stud and nut assembly, as described herein, is provided. The flange members are oriented to align the openings with one another. A stud member is introduced into one of the flange openings. Each of the first and second nut members are sequentially threadingly engaged onto the respective ends of the stud member. Tension is then applied through the stud member to increase the length of the stud member sufficient to elongate the stud within the elastic limits of its composition. The control rod is introduced into at least one of the cavities on at least one of the nuts to manipulate said at least one of the nuts further toward the flanges to secure the nuts to the stud member and upon the flanges in at least hand-tight relationship. Tension is then released through the stud so that the stud thread members and the nut members become lockingly inter engaged and the stud member is in a secured position relative to the flange members. The steps are repeated, as required, in sequential incremental steps around the remaining openings of the flange members.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1  is an illustration, in perspective, of a conventional oil field Christmas tree, with both a conventional stud and nut assembly in place, as well as the stud and nut assembly of the present invention.  
         [0020]      FIG. 2  is an enlarged PRIOR ART perspective view of the conventional stud and nut affixation assembly for flange members of a valve assembly on an oil field Christmas tree, as illustrated in  FIG. 1 .  
         [0021]      FIG. 3  is a view similar to that of  FIG. 2  illustrating the slug and nut assembly of the present invention in completely affixed and secured position relative to flange members.  
         [0022]      FIG. 4  is a perspective illustration of the positioning of a tensioning cell over the slug and nut combination of the present invention as shown in  FIG. 3 .  
         [0023]      FIG. 5  is a perspective and cross-sectional view of the slug and nut combination of the present invention and including a preferred embodiment of metallic bridge means insertable within slots on each of the flanges.  
         [0024]      FIG. 6  is a perspective view looking downward, illustrating an alternate preferred embodiment of the bridging means within a groove on the lower flange members.  
         [0025]      FIG. 7  is a perspective view of the nut member of the present combination showing the internal thread system for same, as the slug is placed in tension.  
         [0026]      FIG. 8  is a perspective illustration of yet another embodiment of the invention, showing a stud where a section thereof is not threaded, as well as yet another embodiment of such a stud wherein a centrally offset section is bored to receive a hardened slug, or a hardened facing section, which is rotated to face outwardly and which, when so positioned, resists sawing to cut the stud.  
         [0027]      FIG. 9  is a view similar to  FIG. 8 , illustrating yet another embodiment, wherein the cavity  23  is replaced by a flat  70 , secured to the outer surface of the conical nut by epoxy, or the like.  
         [0028]      FIG. 10  is a view similar to that of  FIG. 9 , illustrating the removal of the flat  70  after installation, leaving a marked surface  71  in place thereof.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0029]     Now, with first reference to  FIG. 1  (PRIOR ART) there is shown a conventional oil well Christmas tree CT which includes a series of valve housings VH.  
         [0030]     As further detailed in  FIG. 2  (PRIOR ART) the valve housings VH each have a fluid flow conduit FFC centrally disposed there through. The valve housings VH have flanges at each end thereof.  FIG. 2  illustrates the conventional joinder of two valve housings VH including the lower flange B of the upper valve housing VH and the upper flange C of a lower housing VH. As connected, the flanges B, C are secured together, but there is a slight gap or height H there between which disposes to view a short intermediate sectional length of a conventionally threaded nut E. The height H would enable a would-be thief to introduce a hack or other saw or other element between the flanges B and C to fairly easily cut each of the studs E for the removal of components of the Christmas tree CT.  
         [0031]     Also, as illustrated in  FIG. 2 , a conventional internally threaded nut member F is illustrated as torqued to tight engagement on the outer face D of the respective flange faces B and C. The conventional nut F will have a series of circumferentially extending faces G in a plurality of configurations, such as hexagonal, octagonal, or the like. These faces G and their angular positioning around the exterior of the conventional nut F enable a torque wrench to be affixed to the nut to rotate the nut off of the upper end of the stud E for removal of the stud E from secured position on the flanges B and C. This step could be repeated for the plurality of stud and nut combinations secured around the flanges B and C.  
         [0032]     Now referring to  FIG. 3 , there is shown the stud and nut assembly  100  of the present invention in fixed position onto the flange assembly A, as shown in  FIGS. 1 and 2 . The conventional studs E and nuts F have been removed from the bores or holes B- 1  ( FIG. 6 ) disposed and aligned in each of the flanges B and C. The stud  10  has an upper end  10 A and a lower end  10 B. The stud  10 , has an outer central section length  10 C which will have a hardness substantially greater than that for the balance of the length the stud  10  between the upper and lower ends  10 A and  10 B. Preferably, the section length  10 C will have a Rockwell C hardness to at least from between about 55 and about 65.  
         [0033]     The combination stud and nut assembly  100  further comprises first and second nuts  20 A and  20 B. Each of the nuts  20 A and  20 B has an internal threading system  20 C ( FIG. 7 ) for companion inter-engagement with the threading system  10 C ( FIG. 3 ) of the stud  10 .  
         [0034]     Each of the nuts  20 A, and  20 B have first and second ends thereof,  21  and  22 , respectively. One of the ends, preferably the upper end  21 , has a diameter which is smaller than the larger diameter for the other of the ends, such as the lower end,  22 , such that the respective nuts  20 A and  20 B are provided in a smooth conically tapered outer surface  50  extending from the respective ends  21  and  22 . The taper  50  provides a smooth outer surface of the respective nuts  20 A and  20 B, which do not have a plurality of faces thereon, such as the hexagonal or octagonal faces G of the conventional nuts F shown in  FIG. 2 . By providing such a smooth, conically tapered outer surface  50 , a wrench cannot be used to loosen the nuts  20 A,  20 B by application of torque while the stud is in tension. The nuts  20 A and  20 B may also be hardened, preferably to from between about 55 and about 65 Rockwell C hardness.  
         [0035]     In a preferred embodiment the nuts  20 A,  20 B also include at least one torquing cavity  23  defined on the outer surface of each of the nut members  20 A,  20 B for insertion of an adjusting pin  40  for tightening of said nut members onto the stud members  20 A and  20 B as the stud members are placed into tension during affixation. It will be appreciated that, upon completion of the affixation of the nuts  20 A,  20 B onto the studs, the stud will remain somewhat in tension, even though the interengaging threads between the nuts and the studs are in engaged position. Such tensioning of the stud in securement relative to the nuts will further resist application of torque to the nuts and/or the stud to disengage same.  
         [0036]      FIG. 5  illustrates another preferred embodiment showing a series of slots  30 A and  30 B provided in each of the flanges B and C for receipt of metallic bridge means  31  therein. The slots  30 B and  30 C are alignable on the respective upper and lower internal faces of the respective flange members B and C such that the bridge means  31  is inserted in the slots  30 B and  30 C during securement or the nut means  20 A,  20 B onto the nuts  10  and the bridge means are disposed at least partially across that diameter of respective stud E extending between the flanges B and C.  
         [0037]     An additional preferred embodiment is shown in  FIG. 6 , where a groove way  40  is circumferentially extended and defined on each of the inner faces of the flanges B and C an outboard of the openings for the fluid conduit member. A solid, circularly extending metallic bridge means  41  is housed between the groove ways for resisting cutting of the studs E during attempted theft of the Christmas tree CT.  
         [0038]     Now, with reference to  FIG. 8 , the stud  10  may be provided with an unthreaded section  10 C, which may be hardened to from between about 55 and about 65 Rockwell C. This section  1 OC would be designed such that it is placed between the flanges B and C during securement. Also, as shown in  FIG. 8 , a rectangular or other configured slot  10 C′ may be bored into a part of the unthreaded section  10 C to slip into place a companionly snug fitting hardened slug  11 . The slug  11  may be welded into place and may be of tungsten or other comparatively hard material. As illustrated, the slot  10 C′ and slug  11  may be provided in less than a completely radial configuration, such that, for example, the slug  11  is only within, say, about 90 degrees of a complete 360 degree surface area of the portion  10 C. In such case, when the stud  10  is placed between the flanges B and C, the slug  11  may be hand manipulated to turn it such that the slug  11  faces outwardly around the flanges A and B, to further resist sawing or other attempt at removing the stud  10 .  
         [0039]     When it is desired to use the combination stud and nut assembly of the present invention for theft abatement purposes, the conventional nuts F are removed by application of a torque wrench to the respective studs E around the flanges B and C. They are then replaced using the stud  10  of the present invention, with a central section  10 C being aligned between the upper and lower internal faces of the flanges B and C. A nut  20 A is hand rotated onto the upper end  10 A of the stud  10  until its lower face comes into contact with the upper face of the respective flange member B, C. The steps are repeated with the other of the nuts  20 B on the other of the flanges B and C. Thereafter, the nut  10  is placed into tension.  
         [0040]     There are a number of conventional tensioning devices TD well known to those skilled in the art which may be utilized by providing a sleeve for the tensioner (not shown) which has internal threads which are companionly inter-engageable with the threads  10 C of the stud  10 . The sleeve would be placed over the stud  10  with an open end of the sleeve being placed on the upper face of the respective flange B, or C and hydraulically activated to apply tension to the stud  10  to elongate the stud within the elastic limits of its composition. While the stud  10  is placed in tension, a control rod is placed into one of the cavities  23  so that the stud  20 A,  20 B may be manipulated by hand so that it is hand-tight onto the upper surface of the respective flange B or C. When in tension, the respective threads of the slug will still be slightly engaged with the internal companion threads of the nut  20 A,  20 B, even though the stud  10  has been placed in tension and thus elongated. Tension applied to the stud  10  may now be released , but the stud  10  remains in tension due to the continued and further inter-engagement of the threads of the slug and those of the nut, and the tensioned stud and nut combination  100  are tightly secured against the respective flanges B and C.  
         [0041]     It will be appreciated that the length of the stud  10  used to replace the conventional prior art stud E may be somewhat longer than the stud E, in order to provide for acceptance of a sleeve or other component of the tensioning device TD (see  FIG. 7 ).  
         [0042]     While the foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims which follow.