Abstract:
A socket pipe joint includes a male part and a female part in telescopic overlapping position in the joint. An interlocking sleeve member is provided between the male and female parts. Locking elements including the interlocking sleeve member are provided to releasably lock the male part and female part to one another. A locking sleeve is positioned on the male part and extends from a position inside the female part to a position outside an end opening of the female part. A drive assembly is coupled to the locking sleeve on the outside of the joint and is operable to displace the locking sleeve axially between inner and outer positions. A positioning and interlocking element includes a pawl. By axial displacement of the locking sleeve, the pawl is displaced radially, positioning and interlocking the two pipe parts with simultaneous permanent compression of a seal between the pipe parts.

Description:
TECHNICAL FIELD 
     The present invention relates in general to socket pipe couplings with a female part and a male part telescopically engaged in a coupling position. The invention is especially developed for intercoupling pipe line parts in subsea installations, but can also be utilized for other applications. 
     The invention relates especially to socket pipe couplings of the kind wherein is used one or more displaceable sleeves in the joint by radial movement of usually wedge-shaped clamping members, effecting that the two pipe sections are being pressed together to a locked position with a simultaneous compression of interposed seal member or members. 
     BACKGROUND OF THE INVENTION 
     There are known a plurality of socket joints of this type. As illustrative for the prior art one may refer to U.S. Pat. No. 4,652,021, GB 2004341, SE 342495, FR 919287, GB 2223072 and U.S. Pat. No. 4,696,493. The two latter US patents are showing solutions wherein are utilized two overlapping displaceable locking rings on the inside of the joint, which can provide an outwardly directed pressing of wedge-shaped locking pawls with a simultaneously compressing of interposed seal elements. The coupling itself is carried out with a rotating tool which is engaged with the internal locking sleeve. A drawback of the before mentioned solutions is that the operation of the joints depends on a rotary tool which must be positioned inside one of the pipe parts, and necessitates that one of the pipe ends is open. A further drawback is that the packing or seals are positioned on the outside of the joint and therefore are susceptible to influence from outside environments, for instance ambient sea water, simultaneously as packings or seals will be exposed to the media inside the pipes. 
     SUMMARY OF THE INVENTION 
     The main object of the present invention has been to arrive at a simpler and more rugged construction, which simultaneously results in a high pressure resistant intercoupling and sealing between the respective pipe lines and also long durability. A further object of the invention is to provide a quick connect/disconnect coupling, i.e. a coupling with a mechanism which in a simple and quick fashion can be coupled and released, preferably by means of a rotating tool which is positioned on the coupling parts on the outside of the joints. 
     The socket pipe coupling in accordance with the invention is thus of the kind comprising a male part and a female part in an overlapping position in the joint, and wherein the coupling includes one or more displaceable sleeves which, subject to pressure against adjacent preferably wedge-shaped locking elements which thereby being pressed outwardly, can provide interlocking of the pipe parts, simultaneously as the interposed packing elements are subject to a compression, and the invention is characterized in that on the male part in the coupling is positioned a locking sleeve which extends outside of the end opening of the female part, and to manoeuvering means fixedly mounted on the male part for displacement of the sleeve between an inner position and an outer position, the sleeve in the inner position pressing against the locking elements providing compression of an interposed seal member and interlocking of the pipe parts. 
     In a preferred embodiment for the invention the locking sleeve on the male part outside the female part is provided with external threads in engagement with an adjacent mounted gear drive which may be operated by means of an auxilliary power tool. 
     The solution in accordance with the invention facilitates use of one single, preferably wedge-shaped seal ring made of metal or steel and which is positioned in a seat on the inside of the joint between the outside or the inside of the male part, and an adjacent seat surface at the bottom of the female socket. 
     The wedge-shaped locking elements may consist of a number of circumferentially distributed, radially movable locking pawls or dogs having wedge faces in position between the male and the female part in the joint, respectively, or in the shape of a radially flexible ring, a so called split ring (with a transverse slit)—and which by means of the locking sleeve may be pressed outwardly from a retracted resting position to an outer position for engagement between the male part and the female part, and thereby effect interlocking of the pipe parts in the joint and compression of an interposed seal member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     Other features and advantages of the invention will appear from the following specification with reference to the enclosed drawings, which are showing two different applications for the invention, namely a first application wherein the joint is utilized for fastening and coupling of a valve insert in a valve housing, and a second application which relates to the coupling of a well head pipe to a riser pipe for a sea bottom installation, wherein 
     FIG. 1 shows a valve insert for a choke valve of in per se known type, provided with a coupling means in accordance with the invention, 
     FIG. 2 shows a detail section in a large scale of a part of the valve shown in FIG. 1 which is circumscribed with the circle B in FIG. 1, 
     FIG. 3 is a sectional lateral view of a pipe joint of the socket type in accordance with the invention wherein the part to the left of the center line shows the driving means, partly in section, while the part right of the center line shows the coupling in intercoupled position, 
     FIG. 4 is a lateral view of a similar pipe joint of the socket type wherein the drive means for the coupling mechanism is provided with a horizontally or laterally directed coupling box with a drive head and wherein the part to the right of the center line shows a section through the coupling means, 
     FIG. 5 is a detail view in section in an enlarged scale of the part shown inside the circle C shown in FIG. 3, 
     FIG. 6 is a detail view in section showing a special embodiment of the locking pawls, 
     FIG. 7 is view similar to FIG. 5 of an embodiment for an invention wherein the coupling means is utilized for intercoupling two or more parallel pipe lines or pipe jackets, 
     FIGS. 8 a-e  are five detail views which in section illustrates the movement sequence of the parts during the coupling procedure, 
     FIG. 9 is a perspective view of the split ring member. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a valve insert for a vertically mounted choke valve  2 , comprising a lower valve stem  4 , an intermediate supporting section  6  with valve faces/seats. On the upwardly directed valve stem extension is mounted a box  8  which contains manoeuvering equipment for the valve, including a motor etc. The valve insert is per se known. The valve stem has an extension  9  on the top with a gripper head  10  serving as supporting and lifting member for the valve insert, and which further can be utilized as an emergency operating means. 
     On the intermediate section  6  of the valve stem is mounted a drive assembly  11  with a bottom plate  12 , adapted to be biased against the top face  22  of the valve housing  14 , shown in stitched lines. In the shown application for the invention the valve housing  14  constitutes the female part in the coupling, while the valve stem  4  forms the male part. The number  13  designates elements which are utilized for positioning the valve insert on the valve housing, and is of minor interest in connection with the present invention. 
     The coupling mechanism in accordance with the invention is shown in detail in FIG. 2, which shows a section of the part shown inside the circle B shown in FIG. 1, and wherein the same reference numbers designate the same parts as shown in FIG.  1 . Thus, reference number  14  designates the socket shaped valve housing with a seat  16  for the packing or seal ring  18  which as shown preferably consists of a double conical ring of metal or steel. 
     The intermediate part  6  of the valve stem constitutes as mentioned the male part in the joint. On the part  6  is supported an displaceable locking sleeve  20 , the upper part of which is in position outside or above the top face  22  on the valve housing  14  (the female part) and is provided with a threaded section  24  which stands in engagement with inward threads  26  on the circumscribing ring gear  28 , which is journalled in the drive assembly, i.e., the gear box  11  on slide bearings at the top and at the bottom. The outside circumference of the ring gear  28  is in engagement with a worm gear or pinion  32 , provided with an upwardly pointed fixed shaft top extending out of the gear box  11  with a non-circular coupling tap or dowel  34  or the like for positioning an electric or hydraulic power tool. 
     The locking sleeve  20  is non-rotatably journalled on the valve stem  4  by means of a longitudinal slit  38  made in the side face of the valve stem, whereby is positioned a splint  36 , whereby the locking sleeve  20  can be moved upwards and downwards within defined limits. 
     The lower part of the locking sleeve  20  is as shown provided with a reduced section  40  which is terminated with a transverse biasing face  41 . The section  40  is tapered in direction downwards, and can serve as a wedging face. Adjacent the lower part of the locking sleeve is arranged a plurality of circumferentially distributed pawls or dogs  42 , the upper part of which has a tapered or wedge-shaped outwardly directed surface  44  which is contacting a complementary formed biasing face provided on the inside of the valve housing  14 . The lower part of the locking pawls  42  have in the shown embodiment a projection  45  which is positioned in a recess  47  in the valve stem  4  and the bottom face  46  of which is biased against the bottom face  48  in the recess  47 . 
     The coupling joint is in FIG. 2 shown in locked position. In this position the locking sleeve  20  has been displaced or driven downwards along the stem whereby the tapered faces  40  presses the dogs  42  outwardly in wedge-shaped engagement with the surface  44 , simultaneously as the lower part  45  is guided outwardly along the face  48 . The valve stem  4  is thereby simultaneously pressed downwards in the valve housing by means of the locking pawls  42 , the top of which will press against the transverse surface  41  on the locking ring, while the bottom face  46  will press against the surface  48  on the valve stem. Thereby the ring seal  18  will be compressed arresting the valve stem movement, simultaneously as the valve stem is locked with wedging effect by means of the locking pawls  42 . The locking pawls with the adjacent parts are such dimensionally adjusted that the movement of the locking pawls will be stopped by the seal ring  18  before they have reached the bottom, whereby the seal ring  18  will maintain in compression in locked position. 
     When the valve insert shall be released from the valve housing, the locking sleeve  20  is moved upwards by means of the gear drive  24 ,  28 ,  32  which is put into rotation by means of a power tool engaged with the dowel  34 , ending the locking pawls  42  to be displaced radially inwards along the wedged surface  44  simultaneously as they are released from the adjacent part  40  of the sleeve  20 , whereby the entire valve insert including the valve stem  6 , the locking pawls  42 , the locking sleeve  20  and the gear box  11  can be withdrawn upwards out of the valve housing  14  as a unit. The valve can be lowered into the valve insert by gravity. Thereafter the locking sleeve will continue the downward movement. 
     In FIG. 1 the dowel  34  is arranged with an upwardly directed drive shaft  50 , which at the top of the valve insert is coupled to a transfer box  52 , mounted on a transverse stayer  56  positioned on the extension  9  of the drive stem. This supplemental device facilitates the access for a coupling tool mounted on a remotely operated vehicle (ROV). 
     FIGS. 3-7 illustrates a pipe coupling in accordance with the invention for assembling an intercoupling of pipes in subsea position, for instance coupling of a vertical riser pipe on to a production pipe or well head on a bottom based installation. 
     FIGS. 3 and 4 are lateral views partly in section, illustrating two embodiments of the pipe coupling, wherein FIG. 3 shows an embodiment with vertical coupling drive box  66   a , mounted on an upper male part  60 , while the embodiment in FIG. 4 shows a solution with laterally directed coupling drive box  66   b . In both embodiments the lower pipe section  62  is a female part or socket. Disregarding certain detail differences, the coupling shown in FIGS. 3-7 corresponds to the coupling shown in FIGS. 1 and 2 and the same or corresponding parts are to some extent designated with the same reference numbers in all figures. In FIGS. 3 and 4, the number  62  does designate the socket part in the coupling, while the number  60  designates a vertically positioned pipe or male part which shall be coupled to the socket. The coupling shown in FIG. 3 is shown in detail in FIG. 5, which shows an enlarged section of the part designated with the letter C in FIG.  3 . The pipe socket is here shown in stitched lines  62 ′, while pipe  60  is shown in an inserted, but not tightened and locked position. This shall be further described later. In FIG. 5 the ring gear  64  is mounted in the gear box  66  in the same way as shown in FIG.  2  and is engaged via threads  68  to the locking sleeve  20 . The gear box  11  is mounted on the pipe  60  via a coupling ring  70  which is pressing against the pipe along recesses/ridges  72 . The number  74  designates elements for positioning a combined guiding and locking pin. 
     The important constructional difference between the pipe coupling shown in FIG.  2  and FIG. 5, respectively, consists in the design of the locking pawls  80 . In the embodiment shown in FIG. 5 the locking pawls are, namely, realized as one single closed ring element  80  provided with a transverse slit or slits, one such slit being illustrated at  91  in FIG. 9 (see FIG. 9) such that the ring can flex radially. Similarly as the pawls  42  of the embodiment of FIG. 2, the split ring  80  includes a transverse oblique surface  83  engageable by a tapered surface  90  of the locking sleeve  20  and a wedge surface  85  engagable with a generally complementary surface  87  on the female part  62 . The ring is interconnected in a gliding finger joint. This so called split ring  80  is at the bottom preferably furnished with a supporting ring  82  which for instance by means of threads or screws  84  is attached on the lowermost part of the male pipe section. The supporting ring  82  is uppermost provided with throughgoing slits  86  wherein run the heads  88  on threaded bolts  89  which leads through slits in the uppermost part of the ring  82  and are threaded into the bottom part of the split ring  80  as shown. In FIG. 5 the coupling is shown in an intermediate position wherein the male pipe  60  including the entire coupling has been moved down into the female part  62  such that the bottom extremity on the male part is biased against a premounted conical annular seal ring  78  which preferably is made in metal or steel. The split ring  80  is positioned in the spacing between the male part  60  and the female part  62 , and has surface contact with a conically tapered part  90  of the locking sleeve  20  simultaneously as the bottom wall plate  92  in the gear box  66  is biased against the top edge  94  of the female part  62  as shown. When the ring gear is activated, the locking sleeve will be driven downwards and presses the flexible split ring  80  radially outwards, simultaneously as the screw bolts  89  are being displaced outwardly in the slits  86 . 
     FIG. 6 is a fragmentary view showing an embodiment of locking pawls  80 ′ which constitutes a combination of the pawl design shown in FIG.  2  and FIG. 5 respectively. Herein are utilized individual, circumferentially distributed locking pawls  80 ′, the outside of said pawls and the inside of the adjacent, complementary female part  62 ′ are provided with a stepwise design as also shown in FIG. 5 in replacement of even wedging faces as shown in FIG. 2 in order to obtain a positive grip between the adjacent parts. 
     FIG. 7 is a view similar to FIG. 5, wherein the pipe coupling itself is identical to the one in FIG. 5, but wherein the pipe coupling is utilized for simultaneous intercoupling two or more parallel pipe lines in a “bundle” (not shown). The coupling comprises a main tubular pipe module  100  having a center line CL and which is coupled into one single female-part  102  shown in stitched lines. On the right side of the center line CL are in the male pipe module  100  provided tubular bores  104 , while in the female part  102  is provided a complementary pipe-shaped passage  105  provided with interpositioned annular seal rings  106 . It will be understood that in a such main tubular pipe module  100  can be arranged two or more parallel pipe lines or bores assembled in one single coupling joint  103 . On the outside of the gear box  66  are mounted additional conveying means  108  for one or more cables or the like. 
     FIGS. 8 a-e  illustrate the sequence in connection with the coupling operation. FIG. 8 a  shows the position where a male part  60  with all functional parts has been passed down into an intermediate position in a female part  62 , wherein the bottom plate  92  has not yet arrived into contact with the top edge  94  on the female part  62 . The locking sleeve  20  has been driven up to an upper position, enabling that the split ring  80  to flex inwardly to an inner position, and remaining in contact with the lower conical part of the locking sleeve  20 . In that position of sleeve  20 , the split ring  80  is spaced from the inside surface of the female part  62 . 
     FIG. 8 b  shows the position wherein the split ring has been pressed downwards in contact with the inside of the female part  62  simultaneously as the locking sleeve is pressing the split ring  80  outwards. FIG. 8 c  shows the situation when the split ring  80  has arrived into position just above a conically stepped inside of the female part, corresponding to the stepped outside of the split ring as shown. 
     FIG. 8 d  shows the position wherein the male part  60  has been pressed down into contact with the bottom of the female part, simultaneously as the seal ring  78  has arrived into contact with the adjacent inside surface of the male part. When the locking sleeve  20  now is pressed further downwards, the split ring  80  will be pressed radially outwards and be pressed into engagement with the inside of the female part subject to a wedge action, simultaneously as the ring seal  78  is subjected to high compression. The dimensions and the position of the split ring  80  with cooperating engagement faces on the outside of the split ring and the inside of the female part  62  and the packing seal  78 , respectively, are such calibrated that the seal ring will determine the final position of the male part  60 . In this fashion the seal  78  will be subject to a locked compression in the coupling. 
     A substantial advantage with the pipe coupling in accordance with the invention is that the entire coupling procedure can be carried out on the outside of a ready assembled coupling and that the coupling can be carried out by means of one single auxiliary power tool. In addition to a safe and quick coupling, release and disengagement of the coupling parts, the present invention makes it possible to intercouple two or several parallel pipe lines by means of a module assembly, wherein two or several pipes or the like with complementary pipe coupling are present. 
     Intercoupling two or several parallel pipe lines is very important in connection with subsea constructions, wherein the female parts are vertically mounted on a bottom frame and the male parts shall be coupled thereto. The male parts including the coupling implements can then be mounted on a modular frame, which thereafter are lowered down into position on a complementary module with female parts, whereafter the finalizing intercoupling takes place by means of a procedure which is illustrated in FIG.  7 . 
     On the male part may in operational vicinity to the gear housing be arranged a skirt or funnel-shaped device, dimensioned to circumscribe the female part in the coupling. A such device may facilitate positioning and lowering of the male part into the below positioned female part, for instance an outwardly pointing well head or the like.