Abstract:
A dismantling joint for joining a first pipeline component to a second pipeline component including a first half and a second half, the first half including a cylindrical spigot having an outer face and a flange extending outwardly from the outer face of the spigot, the flange having an inner face and an outer face remote from the inner face, and the second half including a socket adapted to slidably receive therein the spigot of the first half, the socket having a proximal end and a distal end remote from the proximal end, the proximal end being opposed to the inner face of the flange of the first half; and forcing means arranged between the inner face of the flange of the first half and the proximal end of the spigot to engage the inner face of the flange of the first half and the proximal end of the socket of the second half adjacent the outer face of the spigot to force the first and second halves away from each other.

Description:
FIELD OF THE INVENTION 
       [0001]    THIS invention relates to pipelines and pipeline components and methods of joining pipes terminated by flanges and flanged pipeline components. The invention has particular application to components known as “dismantling joints” especially in large high pressure pipelines but it can have application in low pressure pipelines. 
       BACKGROUND ART 
       [0002]    Large pipelines typically include a plurality of flanged pipes joined to one another by bolts which pass through the flanges and hold the flanges together. Similarly, components such as valves, pumps and the like are often provided in the pipeline and they also have matching flanges which are joined to the pipe flanges in the same manner. Maintenance and servicing of a pipeline and its components often requires removal and replacement of a length of pipe or a component. It will be appreciated that removal of lengths of pipe or components can be difficult with large pipelines especially where the pipeline is underground or held in place by steel or concrete structures so that the pipeline cannot be axially or laterally moved. Such pipelines generally include dismantling joints between selected pipes or selected components which can be shortened for installation and removal and lengthened once in place to close the gap between the adjacent pipe flanges or component flanges as the case may be. 
         [0003]    The presently known dismantling joints typically include two telescoping pipe or tube portions with flanges which correspond in size to the pipe flanges and they are held in place by bolts which pass through the adjacent pipe flanges (or component flanges) and through the corresponding flanges of the dismantling joint. 
         [0004]    That arrangement can result in bending of the pipe flanges, known as “flange rotation” (a type of “cupping” of the adjacent flanges in the axial direction). Consequently, dismantling joints have require undesirably large heavy flanges to carry the applied loads. 
         [0005]    Moreover, the removal or replacement of an existing dismantling joint is complicated and time-consuming because it is necessary to remove all of the tie-bolts that are used to secure the dismantling joint to adjacent pipeline components before the dismantling joint can be removed or replaced. Access to the nuts and/or bolts also requires dismantling joints to be undesirably long in the axial direction. 
         [0006]    Additionally, when a dismantling joint is installed, there could be some misalignment between the faces of the flanges of the dismantling joint and the mating faces of the adjacent flanges of the pipeline. In existing arrangements, such misalignment is normally taken up by gaskets, but this approach is known to produce an inferior seal for the joint structurally and from the aspect of seal integrity. 
         [0007]    The present invention is aimed at ameliorating at least one of the problems of presently known dismantling joints. The invention is also aimed at providing a dismantling joint which is reliable and efficient in use. 
         [0008]    With the foregoing in view the present invention, in one aspect, resides broadly in a dismantling joint for joining a first pipeline component to a second pipeline component, the first and second pipeline components being connectable to one another along a common axis by a plurality of connectors spaced from the axis and each pipeline component having a sealing face opposed to the other, the dismantling joint including:
       a first half and a second half, each half having a central axis, and the first half including a cylindrical spigot having an outer face and a flange extending outwardly from the outer face of the spigot, the flange having an inner face and an outer face remote from the inner face, and the second half including a socket adapted to slidably receive therein the spigot of the first half, the socket having a proximal end and a distal end remote from the proximal end, the proximal end being opposed to the inner face of the flange of the first half; and   forcing means arranged between the inner face of the flange of the first half and the proximal end of the spigot to engage the inner face of the flange of the first half and the proximal end of the socket of the Second half adjacent the outer face of the spigot to force the first and second halves away from each other and into sealing engagement with the sealing faces of the pipeline components, and wherein       
 
         [0011]    the forcing means is arranged about a pitch circle spaced from the central axes such that the spacing of the pitch circle is less than the spacing of the connectors when the central axes of the dismantling joint are aligned with the common axis of the pipeline components. 
         [0012]    In another aspect, the present invention resides broadly in a dismantling joint for joining a first pipeline component to a second pipeline component, the first and second pipeline components being connectable to one another along a common axis by a plurality of connectors spaced from the axis and each pipeline component having a sealing face opposed to the other, the dismantling joint including:
       a first half and a second half, each half having a central axis, and the first half including a cylindrical spigot and a flange extending outwardly therefrom, the flange having an inner end and an outer end remote from the inner end, the second half including a socket adapted to slidably receive the spigot of the first half, the socket having a proximal end and a distal end remote from the proximal end, the proximal end being opposed to the inner end of the flange of the first half; and   forcing means arranged to engage the inner end of the flange of the first half and the proximal end of the socket of the second half adjacent the outer face of the spigot to force the first and second halves away from each other and into sealing engagement with the sealing faces of the pipeline components, and wherein       
 
         [0015]    the forcing means is arranged about a pitch circle spaced from the central axes such that the spacing of the pitch circle is less than the spacing of the connectors when the central axes of the dismantling joint are aligned with the common axis of the pipeline components. 
         [0016]    Preferably, the forcing means includes a plurality of bolts or screws each threadedly engaged with a threaded passage extending axially through either the flange or the socket such that the head of each bolt or screw abuts the other one of the proximal end or inner face respectively. However, it will be appreciated that the forcing means may take other forms, such as, but not limited to, a plurality of rods which extend between the inner end of the flange of the first half and the proximal end of the socket of the second half, each rod having location means for locating the rods in a radially and circumferentially fixed position with respect to both the flange and socket, and each rod further having threaded portions upon which two nuts are threadedly engaged to be wound away from one another against the inner end of the flange and the proximal end of the socket. The bolts or screws are arranged in circumferentially spaced disposition adjacent the outer face of the spigot, meaning relatively close to the outer face and such that the axial compressive force is exerted close to, or even in substantial alignment with, the pipe wall or equivalent thereto of the pipeline components being joined to one another. By being joined to one another, it. will be appreciated that the pipeline components are joined in axially spaced disposition with the dismantling joint interposed between them. 
         [0017]    It will be seen that the axial or longitudinal compressive force of the forcing means is directed against the flanges of the pipeline components at each end of the dismantling joint, the compressive force being taken up by tie bolts joining the pipeline components to one another. 
         [0018]    In another aspect, the present, invention resides broadly in a dismantling joint for interposition between a first pipeline component and a second pipeline, component joined to one another by pipeline fasteners, the first and second pipeline components being connectable to one another along a common axis by a plurality of connectors spaced from the axis and each pipeline component having a sealing face opposed to the other, the dismantling joint including:
       a flanged spigot having a central axis and a flange and a spigot having an internal passage extending therethrough;   a flange adaptor having a central axis and an internal bore for receiving the spigot;   sealing means interposed between the flange and the flange adaptor for sealing against fluid flow from the internal passage of the flanged spigot;   compression means adapted for interposition between the flange of the flanged spigot and the flange adaptor, the compression means, being operable to impart an axial compressive load therebetween; and wherein   the flange and the flange adaptor are adapted to function independently of the pipeline fasteners and into sealing engagement with the sealing faces of the pipeline components, and wherein       
 
         [0024]    the compression means is arranged about a pitch circle spaced from the central axes such that the spacing of the pitch circle is less than the spacing of the connectors when the central axes of the dismantling joint are aligned with the common axis of the pipeline components. 
         [0025]    In another aspect, the present invention resides broadly in a method of dismantlably joining a first pipeline component to a second pipeline component by pipeline fasteners including:
       providing a flanged spigot having a flange and a spigot having an internal passage extending therethrough;   receiving an end of the flange remote from the flange into an internal bore of a flange adaptor;   sealing the flange adaptor and flange against fluid flow from the internal passage of the flanged spigot to provide an axially expansible flanged assembly;   operatively interposing the flanged assembly between the flanges of the first and second flanged components; and   imparting an axial compressive load between the flange and the flange adaptor independently of the pipeline fasteners.       
 
         [0031]    Preferably, the flange and spigot of the first half are integrally formed and may be in the form of the flanged spigot hereinbefore described. It is also preferred that the flange is at or near one end of the spigot. However, it will be appreciated that the flange and spigot may be separate components having sealing means operatively interposed between the components to seal against fluid flow from the internal passage through the spigot, that is, providing a sealing between the flange and the cylindrical outer face of the spigot. 
         [0032]    Preferably, the sealing means includes a seal and a follower for pressing the seal against the spigot and the flange adaptor. In such form, the follower is in the form of a ring having dimensions substantially commensurate with the dimensions of the flange adaptor. 
         [0033]    Preferably, the compression means includes a plurality of threaded rods and complementary threaded apertures extending axially into or through either, ox both the flange and the flange adaptor. In a preferred form, the threaded rods are provided in the form of bolts having a threaded portion, a non-threaded portion extending axially from the threaded portion and a compression face on the end of the non-threaded portion remote from the threaded portion. The non-threaded portion suitably includes two or more engagement faces for operable association with a wrench or the like far turning the bolts about their axes. Preferably, the compression faces of the bolts are domed to a degree sufficient to permit engagement with a bearing face of the follower substantially centrally of the compression faces notwithstanding engagement with the bearing faces at an angle slightly off perpendicular. 
         [0034]    It will be seen that the compressive load may be imparted by turning the bolts in a direction which unscrews them from the complementary apertures in or through the flange and/or flange adaptor. Preferably, a lock nut is provided on each bolt for locking against rotation of the bolt once the desired compressive load has been provided by the unscrewing of the bolts. 
         [0035]    The flange adaptor may include a rebate or groove for receiving the seal. Preferably, the dismantling joint includes a seal containment ring that surrounds the seal. In a preferred form, the follower includes a plurality of threaded holes. A relief ring may also be provided for operable interposition between the flange adaptor and the seal containment ring. The relief ring includes a plurality of clearance holes sized to permit axial penetration of the bolts therethrough, it being preferred that the clearance holes in the relief ring extend longitudinally all of the way through the relief ring. It is also preferred that the follower further includes a seal backing plate ring located between the relief ring and the flange adaptor. 
         [0036]    Alternatively, the follower includes a plurality of apertures, each of which has a threaded portion and an unthreaded clearance portion, It is also preferred that the apertures extend longitudinally all of the way through the follower. It will be appreciated that the threaded apertures may be provided in an alternative form by incorporating a captured nut in a clearance aperture for each or any one of the threaded apertures. 
         [0037]    The first and second flanged components may be selected from a pipeline, a valve, a pump, a joint or the like. Moreover, the flanged spigot or the flange adaptor may be incorporated into one end of a pipeline fitting such as a pump, valve, joint or the like to enable the fitting to be removed from the pipeline in similar manner to having the dismantling joint hereinbefore described provided separately in axial interposition between a pipeline flange and a flange on the pipeline fitting. 
         [0038]    In another aspect, the present invention resides broadly in a dismantling joint for joining a first pipeline component to a second pipeline component, the first and second pipeline components being connectable to one another along a common axis by a plurality of connectors spaced from the axis and each pipeline component having a sealing face opposed to the other, the dismantling joint including:
       a flanged spigot;   a flange adaptor that receives the flanged spigot;   a seal for sealing between the flanged spigot and the flange adaptor;       
 
         [0042]    a follower for pressing the seal against the flanged spigot and the flange adaptor; and
       a plurality of bolts spaced about a central axis and screwed into a plurality of threaded holes such that the bolts extend longitudinally between the flanged spigot and the follower such that the bolts are able to be partially unscrewed so that they are thereby able to move the flanged spigot and the follower away from each other so that the flanged spigot is able to press a first gasket against the first pipeline component, the flange adaptor is able to press a second gasket against the second pipeline component, and so that the follower is able to press the seal against the flanged spigot and the flange adaptor, and so that the flanged spigot and flange adaptor may be pressed into sealing engagement with the sealing faces of the pipeline components, and wherein       
 
         [0044]    the bolts are arranged about a pitch circle spaced from the central axis such that the radius of the pitch circle is less than the spacing of the connectors from the common axis when the central axis of the dismantling joint is aligned with the common axis of the pipeline components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0045]    In order that the invention may be more readily understood and put into practice, preferred embodiments thereof will now be described, along with a description of a dismantling joint according to the prior art, with reference to the accompanying drawings, in which: 
           [0046]      FIG. 1  is a partial cross-sectional view of pipeline incorporating a first dismantling joint according to the invention; 
           [0047]      FIG. 2  is a partial cross-sectional view of a second dismantling joint according to the invention; 
           [0048]      FIG. 3  is an exploded view of a third dismantling joint according to the invention in juxtaposition with two flanged components of a pipeline between which the dismantling joint may be inserted; 
           [0049]      FIGS. 4 to 7  are side views of a pipeline incorporating the third dismantling joint illustrated in  FIG. 3  in progressive states of assembly; 
           [0050]      FIG. 8  is a side, partly cut-away view of a fourth dismantling joint dismantling joint according to the invention; 
           [0051]      FIG. 9  is a side partly cut-away view of a pipeline incorporating a fifth dismantling joint according to the invention; 
           [0052]      FIG. 10  is a side partly cut-away view of a pipeline incorporating a sixth preferred dismantling joint according to the invention; and 
           [0053]      FIG. 11  is a side partly cut-away view of a dismantling joint according to the invention when joined to a pipeline component. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0054]    In the drawings, like features have been referenced with the same reference numbers. The pipeline  50  illustrated in  FIG. 1  includes a first pipeline component  51 , and a second pipeline component  52 . The first pipeline component  51  includes a pipe  53 , and a flange  54  that is secured to an end  55  of the pipe  53 . The second pipeline component  52  includes a pipe  60 , and a flange  61  that is secured to an end  62  of the pipe  60 . The flanges  54 ,  61 , which are separated from each other by a gap  63 , function as an end  64  of the first component  51 , and an end  65  of the second component  52  respectively. 
         [0055]    The first dismantling joint  70 , which is located in the gap  63 , joins the end  64  of the first component  51  to the end  65  of the second component  52  so that fluid is able to flow through the pipeline  50  from, the pipe  53  and into the pipe  60  through the joint  70 , and vice versa. The joint  70  includes a flanged spigot  71  that includes a spigot or pipe  72  that is welded or otherwise secured to a flange  73  such that the flange  73  is located adjacent an end of the pipe  72 . A first gasket  80  is located between the flange  73  of the flanged spigot  71  and a raised face  81  of the flange  54 . 
         [0056]    A flange adaptor  90  includes a flange  91  and receives the flanged spigot  71  such that the pipe  72  of the flanged spigot  71  is received by the flange  91 . A second gasket  92  is located between the flange  91  of flange adaptor  90  and a raised face  93  of the flange  61 . 
         [0057]    An elastomeric ring seal  100  forms a watertight seal between the pipe  72  of the flanged spigot  71  and the flange  91  of the flange adaptor  90 . The ring seal  100  is surrounded by a seal containment ring  110  which, like the ring seal  100 , abuts the flange  91  of the flange adaptor  90 . The seal containment ring  110  inhibits the ring seal  100  from expanding radially outward when the seal  100  is pressed against the flange  91 . When the seal  100  is pressed against the flange  91 , it also pressed against the pipe  72  of the flanged spigot  71 . 
         [0058]    A follower  120  presses the seal  100  against the pipe  72  of the flanged spigot  71 , and against the flange  91  of the flange adaptor  90  so that the ring seal  100  forms a watertight seal between the pipe  72  and the flange  91 . The follower  120  includes a seal backing plate ring  121 , a relief ring  122 , and a threaded ring  123 . The threaded ring  123  includes a plurality of circumferentially spaced threaded holes  124  that extend longitudinally through the threaded ring  123 . A specially machined compression bolt  125  having a threaded shank a head  127  is screwed into each hole  124  to extend longitudinally between the threaded ring  123  of the follower  120  and the flange  73  of the flanged spigot  71 . 
         [0059]    The relief ring  122  includes a plurality of circumferentially spaced clearance holes  126  that extend longitudinally through the relief ring  122 . Each hole  126  is aligned with a respective threaded hole  124  of the threaded ring  123 , and is dimensioned for clearance fit of the threaded shank of the bolt  125  that is screwed into the threaded hole  124  when so aligned. 
         [0060]    The bolts  125  may be partially unscrewed from the threaded ring  123  such that the head  127  of each bolt  125  presses against the flange  73  of the flanged spigot  71  to move the flanged spigot  71  and the flange adaptor  90  away from each other. In particular, after the bolts  125  are unscrewed from the threaded ring  123  so that their heads  127  contact the flange  73 , further unscrewing of the bolts  125  causes the threaded ring  123  of the follower  120  to move away from the flange  73 . 
         [0061]    As the threaded ring  123  moves away from the flange  73 , it pushes the relief ring  122  of the follower  120  away from the flange  73 , which in turn pushes the seal backing plate ring  121  of the follower  120  away from the flange  73 . The seal backing plate ring  121  in turn pushes the seal  100 , and the seal containment ring  110  away from the flange  73 , and the seal  110  and seal containment ring  110  push the flange  91  of the flange adaptor  90  away from the flange  73 . 
         [0062]    Unscrewing all of the bolts  125  by a sufficient and relatively even amount extends the joint  70  in the above-described manner so that the first gasket  80  is pressed against the raised face  81  of the flange  54  by the flange  73 , the second gasket  92  is pressed against the raised face  93  of the flange  61  by the flange  91 , and so that the seal  100  is pressed against the flange  91  and the pipe  72  by the seal backing plate ring  121  of the follower  120 . 
         [0063]    A predetermined amount of torque is applied to each one of the bolts  125  to ensure adequate compression of the ring seal  100 , and to clamp the gaskets  80 ,  92  securely between the flanges  73 ,  54 , and  61 ,  91 , respectively. Full compression of the ring seal  100  results in the seal  100  providing a leak-proof seal between the flanged spigot  71  and the flange adaptor  90 . 
         [0064]    The seal backing plate ring  121  prevents the bolts  125  from being screwed into and damaging the seal  100 . The ring  121  is made to have a close fit with the outside diameter of the pipe  72  of the flanged spigot  71  to prevent loss of compression of the elastomeric seal  100  through longitudinal extrusion of the compressed seal  100  between the gap between the pipe  72  and the relief ring  122 . 
         [0065]    A plurality of circumferentially spaced holes  130  extend longitudinally through the flange  54 , and a plurality of circumferentially spaced holes  131  extend longitudinally through the flange  61 . Each hole  130  is aligned with a respective hole  131 . The dismantling joint  70  is further secured in position, and the components  51 ,  52  are secured to each other, by a plurality of tie-bolts  132  that each extend longitudinally through a respective pair of aligned holes  130 ,  131 , a plurality of washers  133  that receive the tie-bolts  132 , and by a plurality of nuts  134  that are screwed onto the ends of the tie-bolts  132  and tightened. The washers  133  are located between the nuts  134  and the flanges  54 ,  61 . 
         [0066]    The nuts  134  are tightened so that the flanges  54 ,  61  are pulled towards each other, so that the gasket  80  is further compressed between the flanges  54 ,  73 , and so that the gasket  92  is further compressed between the flanges  61 ,  91 . The gaskets  80 ,  92  are further compressed so that the gasket  80  forms a seal between the flanges  54 ,  73 , and so that the gasket  92  forms a seal between the flanges  61 ,  91 . In particular, the gaskets  80 ,  92  are compressed by the amount required to ensure a leak-proof joint between the flanges  54 ,  73  and between the flanges  61 ,  91 . The inner bolts  125  are subjected to a compressive stress not only as a result of their pressing against the flange  73 , but also as a result of the flanges  54 ,  61  being pulled towards each other. The bolts  125  resist this entire external compressive load. 
         [0067]    The follower  120  applies compression to the ring seal  100 . The thickness of the ring seal  100  is such that, before it is compressed between the seal backing plate ring  121  of the follower  120  and the flange  91  of the flange adaptor  90 , it protrudes from the bore of the seal containment ring  110  towards the follower  120 . The seal  100  is able to be compressed between the seal backing plate ring  121  and the flange  91  until the seal containment ring  110  is in contact with both the flange  91  and the seal backing plate ring  121 . Once the ring  110  is in contact with both the flange  91  and the ring  121  so that an annular cavity  135  defined by the flange  91 , ring  110 , and the ring  121  reaches its minimum size and volume, there are no gaps between the flange  91 , the ring  110 , and the ring  121  through which the seal  100  can escape. The seal containment ring  110  limits the amount by which the seal  100  is able to spread radially outward as it is compressed between the ring  121  and the flange  91 . The compressed seal  100  spreads radially inward so that it is compressed against the pipe  72  of the flanged spigot  71  and forms a seal between the flange adaptor  90  and the flanged spigot  71 . 
         [0068]    The dismantling joint  140  illustrated in  FIG. 2  a simplified dismantling joint  140  that is identical with the dismantling joint  70  illustrated and described with reference to  FIG. 1 , except that, rather than including the seal containment ring  110 , a groove  141  that receives the ring seal  100  is machined into or otherwise formed in a face  142  of the flange  91  such that the groove  141  extends along an inner circumference  143  of the flange  91 . 
         [0069]    Also, the seal backing plate ring  121 , the relief ring  122  and the threaded ring  123  of the dismantling joint  70  have been dispensed with. Instead of the relief ring  122  and the threaded ring  123 , the follower  120  of the dismantling joint  140  includes a modified threaded ring  144  in which the relief ring  122  and the threaded ring  123  of the joint  70  have been integrally formed as a single part. The threaded ring  144  includes a plurality of circumferentially spaced  13  threaded holes  145  that extend longitudinally all of the way through the ring  144 . Each hole  145  includes a threaded portion  146  and an adjoining, non-threaded clearance portion  147 . 
         [0070]    The holes  145  in the threaded ring  144  do not overlie the seal ring  100 . Consequently, there is no need for the dismantling joint  140  to include the seal backing plate ring  121  to protect the seal  100  from being damaged by the bolts  125 , thereby permitting the sealing backing plate ring  121  to be omitted from the dismantling joint  140 . 
         [0071]    The bolts  125  of the dismantling joint  140  are screwed into the holes  145  such that the bolts  125  extend longitudinally between the follower  120  and the flange  73  of the flanged spigot  71 . The flanged spigot  71  and the flange adaptor  90  of the dismantling joint  140  are able to be moved away from each other by unscrewing the bolts  125  in the same manner as described in relation to the dismantling joint  70 . 
         [0072]    Also, the dismantling joint  140  is able to be used to join two pipeline components in a similar manner to the dismantling joint  70 . When the dismantling joint  140  joins two pipe line component s in this way, the follower  120 , which includes the threaded ring  144 , presses the ring seal  100  into the groove  141  so that the seal  100  is pressed against the flange  91  of the flange adaptor  90  and against the pipe  72  of the flanged spigot  71  so as to form a leak-proof seal between the flange  91  and the pipe  72 . Also, the bolts  125  are subjected to a compressive force. Although the dismantling joint  140  is simpler than the joint  70 , the joint  70  has a significant advantage over the joint  140  in that the presence of the seal containment ring  110  in the joint  70  provides for easier removal of the seal  110  when dismantling the joint  70 . 
         [0073]    The dismantling joint  160  illustrated in  FIG. 3  is depicted in juxtaposition with a first pipeline component  51  and a second pipeline component  52  for insertion therebetween. The dismantling joint  160  is identical with the dismantling joint  140  except that the flange  91  of the dismantling joint  160  does not include the groove  141  that receives the ring seal  100 . Instead, the dismantling joint  160  includes the seal containment ring  110  of the dismantling joint  70  to surround the ring seal  100 . Before the dismantling joint  160  is inserted into the gap  63  between the ends  64 ,  65  of the first and second pipeline components  51 ,  52 , the components  51 ,  52  are secured to one another with a pair of tie-bolts  132 . 
         [0074]    Each tie bolt  132  extends longitudinally through a respective hole  130  in the flange  54  and a respective hole  131  in the flange  61 , and is secured to the flanges  54 ,  61  by a pair of washers  133  through which the tie-bolt  132  is inserted, and a pair of nuts  134  that are screwed on to the ends of the tie-bolt  132 . The tie-bolts  132  are positioned such that they are both located at the bottom of the components  51 ,  52 . 
         [0075]    Each tie-bolt  132  extends through a respective spacer tube  161 . The spacer tubes  161  support the dismantling joint  160  after it is inserted between the ends  64 ,  65  of the components  51 ,  52  as shown in  FIG. 7 . The wall thickness of each spacer tube  161  is such that the spacer tubes  161  support the dismantling joint  160  so that it is substantially concentric with the flanges  54 ,  61  and is substantially aligned with the pipeline components  51 ,  52 . After the dismantling joint  160  has been inserted between the ends  64 ,  65  of the components  51 ,  52 , the first gasket  80  is inserted between flange  73  of the flanged spigot  71  and flange  54  of the first component  51  so that the gasket  80  is positioned between flange  73  and the raised face  81  of flange  54 . Also, the second gasket  92  is inserted between flange  91  of the flange adaptor  90  and the flange  61  of the second component  52  so that the gasket  92  is positioned between the flange  91  and the raised face  93  of flange  61 . If the gaskets  80 ,  92  include holes for the tie-bolts  132  to extend through, the gaskets  80 ,  92  are installed prior to installing the first two tie-bolts  132  so that the tie-bolts  132  can be inserted through the holes in the gaskets  80 ,  92 . 
         [0076]    As illustrated in  FIG. 5 , once the gaskets  80 ,  92  have been installed in the aforementioned manner, the compression bolts  125  are partially unscrewed from the threaded ring  144  in sequence so that the bolt heads  127  press against the flange  73  of the flanged spigot  71  and cause the flanged spigot  71  and the follower  120  to move away from each other, which in turn causes the flange adaptor  90 , which the follower  120  pushes against, to move away from the flanged spigot  71 . The bolts  125  are unscrewed so that the first gasket  80  evenly contacts the flange  73  and the raised face  81  of the flange  54 , and so that the second gasket  92  evenly contacts the flange  91  and the raised face  93  of the flange  61 . 
         [0077]    As illustrated in  FIG. 6 , the first and second pipeline components  51 ,  52  are joined to one another by some additional tie-bolts  132  and their associated washers  133  and nuts  134 . The additional, tie-bolts  132  are located at circumferentially spaced positions around the dismantling joint  160  so that the installed tie-bolts  132  are able to effectively restrain the flanges  54 ,  61  against further unscrewing of the bolts  125 . Once the additional tie-bolts  132  and their associated washers  133  and nuts  134  have been installed, all of the bolts  125  are further unscrewed from the threaded ring  144  to the required predetermined torque to ensure full compression of the ring seal  100 , secure clamping of the gasket  80  between the dismantling joint  160  and the first component  51 , and secure clamping of the gasket  92  between the dismantling joint  160  and the second component  52 . 
         [0078]    All of the remaining tie-bolts  132  and their associated washers  133  and nuts  134  are then fitted, and the nuts  134  torqued up to the required setting in accordance with approved procedures for the gaskets  80 ,  92  resulting in a completed pipeline portion  170  including the first component  51  joined to the second component  52  by the dismantling joint  160  as shown in  FIG. 10 . The nuts  134  are tightened so as to increase the compression of the gaskets  80 ,  92  to the value required to ensure a leak-proof joint. At this point, the bolts  125  resist the entire external load through compressive stress. Compression of the ring seal  100  between the flanged spigot  71  and the flange adaptor  90  occurs at the same time and in conjunction with the joint components, including the flanges  73 ,  91 , follower  120 , and bolts  125  going into compression. Consequently, unlike conventional dismantling joints, no additional tightening and retightening of the bolts  125  is required after the remaining tie bolts  132  and their nuts  134  have been installed. 
         [0079]    The same basic installation procedure is used regardless of the size of the components, including the components  51 ,  52  and the dismantling joint  160 . The procedure for installing the dismantling joint  160  as just described enables the joint  160  to be installed faster than dismantling joints of the prior art. It also results in a joint assembly that is more reliable than joint assemblies of the prior art. The procedure saves time in the field and is more cost effective compared with dismantling joints of the prior art. The reverse of the above-described procedure is used to uninstall the dismantling joint  160 . 
         [0080]    The dismantling joint  180  illustrated in  FIG. 8  is identical with the dismantling joint  70  except that, the relief ring  122  and threaded ring  123  of the follower  120  have been dispensed with and replaced by a modified relief ring  181  and a plurality of nuts  182 . Each bolt  125  is screwed into a threaded hole  183  in each nut  182 . The relief ring  181  includes a plurality of circumferentially spaced clearance holes  184  that are each for receiving a threaded shank of a respective one of the bolts  125 . 
         [0081]    A plurality of circumferentially spaced recesses  185  are formed in an end face  186  of the relief ring  181 . Each recess  185  is aligned with a respective one of the holes  184  and has a peripheral shape that allows one of the nuts  182  to be received therein and be restrained from rotating relative to the relief ring  181 . This enables the flanged spigot  71  and the follower  120  to be moved away from each other by unscrewing the bolts  125  from the nuts  182  so that the joint  180  can join two pipeline components to each other. When the pipeline components are joined to each other, the bolts  125  are in compression. Incorporating the nuts  182  into the follower  120  enables the economic manufacture of the nuts in corrosion resistant material, similar to the compression bolts  125 . The relief ring  181  could be economically produced by casting or machining. 
         [0082]    The portion of a pipeline  190  illustrated in  FIG. 9  includes a dismantling joint  191  that joins a first pipeline component  51  and a second pipeline component  52 . The dismantling joint  191  is identical with the dismantling joint  70  except that the follower  120  of the dismantling joint  190  replaces the follower  120  of the joint  70  with a thicker seal backing plate ring  192 . In addition, the flange  73  of the flanged spigot  71  includes a plurality of circumferentially spaced threaded holes  193  in an end face  194  of the flange  73 . The bolts  125  are screwed into the holes  193  so that the bolt heads  127  abut against the seal backing plate ring  192  as shown. 
         [0083]    The bolts  125  are partially unscrewed from the flange  73  so that they press against the follower  120  which includes the seal backing plate ring  192  which in turn presses against the ring seal  100  so that the seal  100  forms a seal between the flange  91  of the flange adaptor  90  and the pipe  72  of the flanged spigot  71 . A gasket  80  is pressed between the flange  73  of the flanged spigot  71  and a raised face  81  of a flange  54  of the first component  51 . A gasket  92  is pressed between the flange  91  of the flange adaptor and a raised face  93  of the second component  52 . Also, the bolts  125  are compressed. 
         [0084]    The portion of a pipeline  200  illustrated in  FIG. 10  includes a dismantling joint  201  that joins a first pipeline component  51  and a second pipeline component  52 . The dismantling joint  201  is identical with the dismantling joint  190  except that the flanged spigot  71  of the dismantling joint  190  has been replaced with a modified flanged spigot  202  that is identical with the flanged spigot  71  except that it includes a thin flange  203  rather than the thicker flange  73  of the flanged spigot  71 . The thin flange  203  does not include any threaded holes for the bolts  125  to screw into. In addition, the dismantling joint  201  includes a threaded ring  204  that receives the flanged spigot  202  and abuts against the thin flange  203 . 
         [0085]    A plurality of circumferentially spaced holes  205  extend longitudinally through the threaded ring  204 . Each hole  205  includes a threaded portion  206  and an adjoining non-threaded clearance portion  207 . The bolts  125  of the dismantling joint  201  are screwed into the holes  205  such that the bolts  125  extend longitudinally between the follower  120 , which includes the seal backing plate ring  192 , and the threaded ring  204 , and such that the bolt heads  127  abut against the seal backing plate ring  192 . Because the threaded ring  204  is situated beside the flange  203  of the flanged spigot  202 , the bolts  125  effectively extend longitudinally between the follower  120  and the flanged spigot  202 . The threaded ring  204  supports the thin flange  203  in a flat condition that provides a suitable face for the gasket  80  to seal against the mating flange face  81 . 
         [0086]    The bolts  125  of the dismantling joint  201  are partially unscrewed from the threaded ring  204  so that they press against the follower  120  which includes the seal backing plate ring  192  which in turn presses against the ring seal  100  so that the seal  100  forms a seal between the flange  91  of the flange adaptor  90  and the pipe  72  of the flanged spigot  202 . A gasket  80  is pressed between the flange  203  of the flanged spigot  202  and a raised face  81  of a flange  54  of the first component  51 . A gasket  92  is pressed between the flange  91  of the flange adaptor  90  and a raised face  93  of the second component  52 . Furthermore, the bolts  125  are compressed. The dismantling joint  201  has the most compact design of all of the dismantling joints described herein. The manufacture of the various components of the joint  201  is simplified so that there is a minimum amount of welding required. 
         [0087]    The portion of a pipeline valve  210  illustrated in  FIG. 11  incorporates a dismantling joint  211 . The valve  210  is shown joined to another pipeline component  212 . The dismantling joint  211  is identical with the dismantling joint  70  depicted in  FIG. 4  except that rather than including the flange adaptor  90  of the joint  70 , the joint  211  includes a flange adaptor  213  that includes a flange  214 . The flange  214  is part of a valve body  215 , and surrounds a first opening  216  in the valve body  215 . In addition to including the flange  214 , the valve body  215  includes a second opening  217 , and a flange  218  that surrounds the second opening  217 . The flanges  214 ,  218  each include a plurality of circumferentially spaced threaded holes  219  that extend longitudinally through them. 
         [0088]    The valve  210  is joined to the pipeline component  212  and to another pipeline component (not depicted) that is separated from the component  212  by a gap by positioning the valve  210  in the gap such that the flange  73  of the dismantling joint&#39;s flanged spigot  71  is located adjacent a flange  220  of the component  212  and such that the flange  218  of the valve body  215  is located adjacent the other component. 
         [0089]    The valve  210  and the component  212  are secured to one another by screwing an end of each one of a plurality of tie-bolts  132  into a respective one of the threaded holes  219  in the flange  214 , and the other end of each tie-bolt  132  is inserted through a respective one of a plurality of circumferentially spaced holes  221  that extend longitudinally through the flange  220 . The ends of the tie-bolts  132  that extend longitudinally through the holes  221  are each inserted through a respective washer  133 , and a respective nut  134  is then screwed on to each of those ends so that the valve  210  is thereby secured to the flange  220  of the component  212 . 
         [0090]    A first gasket  80  is positioned between the flange  73  and a raised face  81  of the flange  220 , and a second gasket (not depicted) is positioned between the other component and the flange  218 . The compression bolts  125  of the dismantling joint  211  are partially unscrewed from the threaded ring  124  of the dismantling joint  211  so that the bolt heads  127  press against the flange  73  of the flanged spigot  71  and cause the flanged spigot  71  and the flange adaptor  213  to move away from each other. 
         [0091]    The bolts  125  are unscrewed, and the nuts  134  are tightened so that the first gasket  80  is compressed between the flange  73  and the raised face  81  of the flange  220  so that the gasket  80  forms a watertight seal between the flange  73  and the flange  220 , and so that the second gasket is compressed between the flange  218  and the other component so that the second gasket forms a watertight seal between the flange  218  and the other component, and also so that the ring seal  100  of the dismantling joint  211  is compressed between the flange  214 . of the flange adaptor  213  and the pipe  72  of the flanged spigot  71  so that the ring seal  100  forms a watertight seal between the flange adaptor  213  and the flanged spigot  71 . Furthermore, the bolts  125  are compressed. 
         [0092]    If the other component includes a flange, and the second gasket is positioned between that flange and the flange  218 , the flange  218  may be secured to the flange of the other component in an appropriate manner so that, the second gasket forms a seal between the flange of the other component and the flange  218 . For example, the flange  218  may be secured to the flange of the other component by a plurality of bolts that are each inserted through a respective hole in the flange of the other component and that are each screwed into a respective one of the threaded holes  219  of the flange  218 . Joining the component  212  and the other component with the valve  210  results in a completed pipeline portion  222 . 
         [0093]    The dismantling joint according to the present invention uses considerably less material than prior, art dismantling joints. This is because it is significantly smaller in outside diameter and shorter in length compared with prior art dismantling joints. At the same time, the dismantling joint of the present invention may be rated for use at the same pressures as prior art dismantling joints. The reduction in the outside diameter of the dismantling joint according to the present invention is achieved because the joint does not have conventional flanges of the type that are adapted to be bolted to the flanges of the components to be joined to one another. The outside diameter is equivalent to the outer diameter of the raised faces of the mating flanges of the pipeline components that the dismantling joint joins to one another. 
         [0094]    As the volume of material in a disc or annular ring is a function of the square of the diameter of the disc or ring, a reduction in the outside diameter significantly reduces the amount of material in the disc or ring, which significantly reduces the weight of the disc or ring. Therefore, as a consequence of the dismantling joint according to the present invention having smaller flanges than prior art dismantling joints, the weight of the dismantling joint according to the present invention is significantly less than prior art dismantling joints. Reduction in the length of the dismantling joint according to the present invention is achieved by the compact nature of its design. This has a direct effect on the weight and cost of the unit, and also reduces the cost of the tie-bolts used to secure the mating flanges of the components joined to one another. The combined effects of these material savings results in a lighter more economic design that is able to utilise more expensive, but desirable materials such as stainless steel for critical components resulting in a low maintenance long life application in adverse conditions. 
         [0095]    For applications requiring a large diameter, high pressure joint, it is possible to further reduce the material required to produce a dismantling joint according to the present invention compared to the amount of material required for a prior art dismantling joint. The flanges of prior art dismantling joints are designed to withstand significant bending moments caused by the tie-bolts that secure the flanges to the mating flanges of the joined pipeline components. Because the end flanges of the dismantling joint according to the present invention are not subjected to the same high bending stress as the flanges of prior art dismantling joints, the design thickness of the flanges of the dismantling joint according to the present invention can be based primarily on the gasket compressive load (i.e. the load exerted on the flanges when they compress the gaskets between the dismantling joint and the mating flanges of the joined components). This results in thinner flanges for the dismantling joint according to the present invention for the same pipeline pressure. All of the above-mentioned factors reduce the manufacturing cost, material used, and weight of the dismantling joint according to the present invention when compared to prior art dismantling joints. 
         [0096]    The dismantling joint according to the present invention is not affected by flange rotation as the longitudinal compressive forces on the joint are counteracted by the compression of the bolts  125 , which are located at the centre of the gasket line of action, and which therefore produce no bending stress on the end flanges of the joint. This means that the end flanges remain flat/unbent so that they can provide good support across the width of the gasket face. Although flange rotation will still be apparent on the mating conventional flange of the joined pipeline components, the mating gasket joint will be significantly less than the rotation of a conventional flange joint. A significant effect of this is a reduction in the wetted surface area of the flange face, reducing the area of the flanges that are exposed for potential corrosion. 
         [0097]    Dismantling joints are classified as either restrained or non-restrained depending on whether they are capable of transmitting longitudinal force or not. The restrained type includes a Sub-type of partially restrained types if their restraint system does not allow them to take the full pipeline thrust generated by a dead end cap or 90 degree bend. Non-restrained dismantling joints, are generally cheaper than a restrained type because of their simpler construction. The dismantling joint according to the present invention is classified as a fully restrained system, but it can also be used in nearly all non-restrained applications as well. 
         [0098]    It will be appreciated that in nearly all situations, mating flanges of pipeline components will be installed with some angular inaccuracy, i.e. the flange faces of the mating flanges might not be exactly parallel to each other, resulting in joint deflection. The dismantling joint according to the present invention accommodates some joint deflection by providing the heads  127  of the compression bolts  125  with a spherical contact surface, and by providing relief on other components which provides space for the various component rotations. 
         [0099]    The modular nature of the dismantling joint according to the present invention means that it is easy to incorporate into other pipeline fittings, e.g. valve bodies where the flanged end of the valve body can be easily modified to function as the flange of the flange adaptor or flange spigot of the dismantling joint making it possible to combine the valve and the dismantling joint into a single unit. An advantage of combining the dismantling joint according to the present invention with another component such as a valve is that it eliminates one of the gasket joints of the dismantling joint, and one flange component, and makes the entire assembly shorter than it would otherwise be. 
         [0100]    The dismantling joint according to the present invention can be used in all flange applications and is not limited to use in a particular industry. For example, it could be used in the water, waste water, oil, gas, chemical, and process industries. The materials from which the flange and ring seal are made may need to be altered to enable the joint to be used in a particular application. The various components of the dismantling joint may be manufactured from a material selected for the particular application, such as, for example, steel, stainless steel, and/or ductile cast iron. The manufacture of the components of the dismantling joint according to the present invention is similar to that of prior art dismantling joints in that they can be cut, cast, machined, or otherwise fabricated from selected raw materials. 
         [0101]    Active components of the dismantling joint according to the present invention are under compressive loading once the dismantling joint has been installed in a pipeline. However, the compressive load is lower than that found in prior art dismantling joints. The dismantling joint according to the present invention may be installed in a similar manner to prior art dismantling joints in that the sealing faces of the pipeline and component flanges are secured to the mating faces of the dismantling joint to produce a leak-proof seal in the pipeline. 
         [0102]    During installation of the dismantling joint according to the present invention, the joint is placed between the pipeline and component flanges. The bolts  125  of the joint are screwed out/unscrewed so that the flange adaptor and the flanged spigot are pushed into contact with the flanges of the pipeline components. This action also compresses the ring seal of the joint so that it provides a leak-proof seal between the pipe section of the flanged spigot and the flange of the flange adaptor. The bolts of the joint, are tightened to a predetermined torque. 
         [0103]    Not all dismantling joints according to the present invention require a seal backing plate ring. The seal backing plate is only required for flange sizes where the holes, in the relief ring or the threaded ring may encroach in the area of the ring seal space, preventing the seal from being compressed evenly. Similarly to prior art dismantling joints, the dismantling joint according to the present invention can tolerate axial misalignment or angular deflection between the flange faces of the pipeline and component flanges. This is achieved by the amount that the bolts  125  are adjusted, and by a predetermined amount of clearance between the components of the joint that interact with the flanged spigot component of the joint. To remove the dismantling joint, the aforementioned installation procedure is reversed. 
         [0104]    The provision of a seal containment ring in the dismantling joint according to the present invention provides an alternative option to using a groove in the flange adaptor to provide a sealing cavity to contain the ring seal. The seal containment ring also allows for easy removal of the ring seal so that it is easier to shorten the dismantling joint. Where a seal containment ring is not provided, the seal ring can become wedged, seized, or stuck over time, and make it difficult for the joint to be removed. The ability to move the seal containment ring relative to the flange adaptor aids in the removal of the seal. 
         [0105]    The dismantling joint according to the present invention is simpler, smaller and lighter in design and construction than prior art dismantling joints. As a consequence, it is more cost effective to manufacture and easier to install compared with prior art dismantling joints. This is able to provide the dismantling joint according to the present invention with a competitive advantage in the market place. It is also shorter in length compared with existing dismantling joints that are designed for use with large diameter pipelines, and therefore allows pipeline structures to be reduced in size, which can save costs. 
         [0106]    Where existing dismantling joints need to be replaced due to corrosion or damage, the dismantling joint according to the present invention can be easily lengthened to ensure that it is able to be fitted between the flanges of the pipeline components to be joined to one another. In contrast, existing dismantling joints that are too long cannot be shortened and therefore cannot be installed. Dismantling joints come in a wide range of diameters, from 100 mm to greater than 2 metres. The competitive advantage of the dismantling joint according to the present invention over prior art dismantling joints increases as the diameter of the joint increases. 
         [0107]    It will be appreciated by those skilled in the art that variations and modifications to the invention described herein will be apparent without departing from the spirit and scope thereof. The variations and modifications as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth. Prior art referred to herein does not necessarily form part of the common general knowledge in the art.