Abstract:
At least first and second substantially rigid tubular members having a through bore, and in most instances more than two tubulars, are connected together to form a support apparatus such that a moveable joint is provided between the first and second tubular members. The members typically form a conduit inserted into a substantially flexible tubing, where the support apparatus prevents crushing or collapse of the flexible tubing in environments having a higher exterior pressure with respect to the interior pressure of the flexible tubing, such as subsea environments. The moveable joint typically permits articulated or pivoting movement to occur between the first and second tubular members.

Description:
RELATED APPLICATIONS AND CLAIM OF PRIORITY  
       [0001]     This application claims priority to United Kingdom patent application no. 0408944.7, filed Apr. 22, 2004, which is hereby incorporated by reference in its entirety.  
       TECHNICAL FIELD  
       [0002]     The present invention relates to support apparatus and a method for supporting substantially flexible tubing or hose, more particularly but not exclusively, relates to flexible hose support apparatus for use deep subsea in the hydrocarbon exploration and production industry.  
       BACKGROUND OF THE INVENTION  
       [0003]     In the hydrocarbon exploration and production industry it is often necessary to provide fluid communication and/or transfer fluids, for example drilling fluid, hydraulic fluid, production fluid etc. from one piece of subsea equipment to another piece of subsea equipment. This is typically performed by connecting a length of flexible tubing between fluid ports on each piece of subsea equipment and transferring the fluid there along. Using flexible tubing for this purpose is preferable to using rigid tubing since the flexibility of the tubing allows it to be connected to each piece of equipment relatively easily. In addition, when attached at each end, each piece of equipment may move with respect to one another without the need for the tubing to be disconnected.  
         [0004]     The flexibility of such tubing is obtained by manufacturing the tubing from a relatively thin walled suitable material such as an elastomeric material although the tubing is usually reinforced with integral helically coiled lengths of steel wire in order to provide some measure of strength to the tubing. However, the requirement for the tubing to be relatively lightweight and to have relatively thin walls can often result in the tubing collapsing due to the large hydrostatic pressure exerted on it by the large depth of water above it in typical subsea operating conditions.  
         [0005]     Though flexible tubing is generally manufactured with the helically arranged reinforcing wires integrated into the tubing walls, this is limited to being relatively thin so that it does not adversely affect the flexibility of the tubing and is therefore often not sufficiently rigid enough to prevent the flexible tubing from collapsing under pressure.  
       SUMMARY OF THE INVENTION  
       [0006]     According to the present invention there is provided a method of supporting tubing, the method comprising the steps of: inserting at least first and second substantially rigid tubular members into the tubing, each substantially rigid member comprising a through bore; and connecting the first and second tubular members such that a moveable joint is provided between the first and second tubular members.  
         [0007]     Typically, the method results in that collapse of the tubing, which may be a relatively flexible hose, is substantially prevented whereby an outer surface of the tubular members provides a support to an inner surface of the flexible hose.  
         [0008]     Typically, the method further comprises placing the tubing in water in use of the tubing to provide a fluid communication path, and the method typically further comprises the tubular members substantially preventing collapse of the flexible hose when a differential pressure is acting to attempt to collapse the flexible hose.  
         [0009]     According to the present invention there is also provided support apparatus comprising: at least first and second substantially rigid tubular members each comprising a through bore; and connection means for selectively connecting the first and second tubular members such that a moveable joint is provided between the first and second tubular members.  
         [0010]     Typically, the support apparatus comprises a conduit which is preferably adapted to be inserted into a substantially flexible tubing or hose where the support apparatus is preferably adapted to prevent crushing or collapse of the flexible tubing or hose particularly where the flexible tubing or hose is used in environments having a higher exterior pressure with respect to the interior pressure of the flexible tubing or hose.  
         [0011]     Preferably, the moveable joint provided by the connection means permits articulated movement to occur between the first and second tubular members. The articulated movement permitted typically comprises movement of the first and second members in a pivoting relationship which may be movement of a longitudinal axis of the first tubular member with respect to a longitudinal axis of the second tubular member within a cone projecting away from the end of the second tubular member, the closest ends of the pair of longitudinal axes preferably remaining intersected at the same point whilst the first and second tubular members are connected. Most preferably, the connection means comprises a ball joint provided on one of the first and second tubular members and a socket joint provided on the other of the first and second tubular members.  
         [0012]     Preferably, the connection means is adapted to substantially prevent longitudinal movement of the first tubular member with respect to the second tubular member.  
         [0013]     Preferably the connection means comprises a female or socket connection portion on one of the first and second tubular members and a male or ball connection portion on the other of the first and second tubular members. More preferably, the connection means further comprises a retaining lip on the female connection portion adapted to be retained within a lip retaining groove which is preferably provided adjacent the male connection portion. Preferably, the retaining lip is provided with a radius which assists connection of the female connection portion to the male connection portion.  
         [0014]     Typically, the first tubular member is provided with a female connection portion and a male connection portion, the latter of which may typically be connected to the female connection portion of the second tubular member. This connection is typically performed until the desired length of the apparatus is achieved.  
         [0015]     Alternatively, the first tubular member is provided with first and second male connection portions which may be connected to a second tubular member having first and second female connection portions. Such tubular members may be alternately connected until the desired length of apparatus is achieved.  
         [0016]     Typically, a plurality of tubular members are provided such that when the plurality of tubular members are connected to one another, one end of the apparatus may be angularly displaced with respect to the other without substantially tensioning or compressing the tubular members.  
         [0017]     This provides a support apparatus which may be formed from substantially rigid tubular members but which allows the apparatus as a whole to flex.  
         [0018]     Preferably, the support apparatus is provided with at least a tubing connection socket which is adapted to allow connection of a portion of the apparatus to flexible tubing/hose. Preferably, the tubing connection socket is provided with a gripping portion adapted to allow the flexible tubing to be gripped on the tubing connection socket. Preferably, the tubing connection socket is provided with connection means having a male connecting portion adapted to engage with the female connection portion of at least one tubular member. Alternatively, the tubing connection socket is provided with connection means having a female connection portion adapted to engage with the male connection portion of at least one tubular member.  
         [0019]     Preferably, the tubing connection socket is provided with attachment means adapted to allow attachment of the tubing connection socket to further discrete components. Preferably, the attachment means comprises a joint which may comprise a thread formed thereon.  
         [0020]     Typically, a tubular connection member having first and second female connection portions may be provided in order to provide connection between a male connection portion of a tubular member and a male connection portion of the tubing connection socket.  
         [0021]     Optionally and/or alternatively, the connection means may comprise further retaining means in order to retain a portion of the first tubular member in engagement with the second tubular member. Optionally, the further retaining means comprises a wire or other suitable member inserted between a portion of the first and second tubular members. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]     Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings, in which:  
         [0023]      FIG. 1  is a cross sectional view of the apparatus in accordance with the present invention showing one link of the apparatus in a flexed position;  
         [0024]      FIG. 2  is a detailed cross sectional view of a male-female link of the apparatus of  FIG. 1 ;  
         [0025]      FIG. 3  is a detailed cross sectional view of a female-female link to be used in conjunction with the apparatus of  FIG. 1 ;  
         [0026]      FIG. 4  is a schematic diagram of a tail piece to be used in conjunction with the apparatus of  FIG. 1 ;  
         [0027]      FIG. 5  is a schematic cross sectional diagram illustrating the attachment of the tail piece of  FIG. 4  to a flexible hose to be supported;  
         [0028]      FIG. 6   a  is a partial cross sectional view of a less preferred but alternative embodiment of the present invention; and  
         [0029]      FIG. 6   b  is a partial cross sectional view of a less preferred but further alternative embodiment of the present invention. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0030]     In the following description it should be noted that the term “flexible tubing” should be regarded as a hose or tubing which has a greater degree of flexibility than a substantially rigid member. In other words, though flexible, the hose or tubing possesses a, not insignificant, degree of rigidity. Also, in the following description the reader should note that the term “male-female” member should be regarded as a member having a male connection at one end and a female connection at the other end, and appropriate permutations of this term used in the following description should be regarded accordingly.  
         [0031]     Support apparatus  10  comprises a series of substantially tubular links  12  each having a male end  14  and a female end  16 .  
         [0032]     The male end  14  of each link  12  has a surface  18  which is curved by a radius R m  ( FIG. 2 ) with respect to the link  12  longitudinal axis, and extends around the circumference of the male end  14  of the link  12 . A groove  20  is formed inwardly of curved surface  18 , around the outer circumference of a portion of the link  12  adjacent the male end  14  and is curved by a radius R g . A shoulder  52  comprising an angled or radiused face is provided between the curved surface  18  and the groove  20 , where the angled or radiused face of the shoulder matches the angle or radius of a bead  24  having a curved surface as will be described subsequently. A second shoulder  54  also comprises a face lying in a direction substantially perpendicular to the longitudinal axis is provided at the other (innermost) end of the groove  20 .  
         [0033]     The female end  16  of each link  12  has an internal curved surface  22  which tapers by a radius R f  from the through bore  56  of the tubular link  12  toward an inwardly projecting bead  24 . The bead  24  extends around the inner circumference of the female end  16  and is provided with a curved surface, the purpose of which will be described subsequently.  
         [0034]     In this embodiment the radius R m  of the curved surface  18  of the male end  14  is manufactured to be the same as the radius R f  of female end  16 . Typical radii for each of R f  and R m  in this embodiment would be defined by an arc swept through an angle, the radius of the arc being related to the diameter of the insert links  12 ,  26 . For instance, the radius of the arc may be around 1.9 inches (approximately 48 mm) from the longitudinal axis of the link  12  when the outer diameter of the link  12  is in the region of 3.95 inches. The reason for the similarity in radii, R f  and R m , will be described subsequently.  
         [0035]     It should also be noted that the outer diameter of the links  12  is manufactured to be at least a sliding fit with the internal diameter of the flexible hose  38  into which the apparatus  10  is to be inserted, as will be subsequently described.  
         [0036]     Referring to  FIG. 3 , a female-female link  26  having a pair of female ends  16  is also provided.  
         [0037]     The female-female link  26  is substantially the same as the link  12  previously described with the important difference that it has a female end  16  in place of the male end  14  present on the link  12 .  
         [0038]     Referring to  FIG. 4 , a tail piece connector  28  is provided. The tail piece connector  28  comprises a substantially tubular member having a male connection socket  30 , a serrated grip  32 , and a connection collar  34 .  
         [0039]     The male connection socket  30  is similar to the male end  14  of each link  12  and therefore no further description of it  30  is necessary.  
         [0040]     The connector  28  shown in  FIG. 4  has a neck A,B which may be used during testing of the apparatus  10 ; however, in operation, when used to transfer fluid between subsea components, the bore  58  through the tail piece  28  will remain substantially constant from one end to the other. In this regard, the reader should note that in operation the shaded sections A and B (shown in  FIGS. 4 and 5 ) are omitted. In addition, a joint  46  is provided in order to allow connection of the apparatus  10  to subsea equipment. The joint  46  may be threaded (as shown in  FIG. 4 ) or may be in the form of a flange (not shown) and may be a male joint  46  (as shown in  FIG. 4 ) or may be a female joint (not shown), depending upon the connection required.  
         [0041]     The serrated grip  32  has a number of angled protrusions which extend around the circumference of the tail piece  28  and their purpose will be described subsequently.  
         [0042]     In use, a number of the links  12  are placed (for instance by sliding action) inside standard flexible tubing  38  ( FIG. 5 ) during installation of the apparatus  10 . For the sake of clarity, connection of a first link  12  to a second link  12  will now be described though the skilled reader will realise that the connection operation could be performed using an installation machine (not shown) having a magazine loaded with links  12 . In such an automated installation system the magazine elastically deforms the female ends  16  of the links  12  and inserts the deformed female end  16  over the male end  14  (or inserts the male end  14  into the deformed female end  16 ) of the uppermost link  12  and then progresses each newly inserted link and hence the rest of the apparatus  10  down the inside of the tubing  38 .  
         [0043]     Whilst installing the female end  16  on the male end  14 , the female end  16  of a link  12  is urged against the male end  14  of a further link  12  until the innermost surface of the bead  24  of the female end  16  abuts against the curved surface  18  of the male end  14 . Further progression of the female end  16  and hence the bead  24  against the curved surface  18  causes the wall of the female end  16  and in particular the bead  24  to be urged radially outwardly due to the radius R m  of the curved surface  18 . The curved surface of the bead  24  provides a minimum contact area between the bead  24  and the curved surface  18  which eases insertion of the male end  14  into the female end  16 . The radially outward movement of the female end  16  caused by progression of the female end  16  onto the male end  14  continues until the bead  24  reaches the edge of the groove  20 , at which point the resilient properties of the female end  16  (which is typically made of steel but may be made from any other suitable material) snaps the bead  24  into the groove  20 , and the perpendicularly projecting shoulder  52  prevents the bead  24  from moving back down the curved surface  18 . At this point the curved surface  18  of the male end  14  comes into contact with the internal curved surface  22  of the female end  16  and the bead  24  resides within the groove  20 . The first link  12  is now securely and moveably connected to the second link  12 .  
         [0044]     The above connection operation is repeated until a sufficient length of links  12  is created in order that the apparatus  10  substantially resides within the length of the flexible tubing  38 .  
         [0045]     Referring to  FIG. 5 , the female end  16  of the left hand most end of the apparatus  10  as viewed in  FIG. 1  may now be connected to the male end  30  of the tail piece  28  by forcing the female end  16  over the male end  30  in a similar manner to that previously described for connecting each link  12 . The flexible tubing  38  is then attached around the outer circumference of the tail piece  28  by sliding it over the serrated grip  32 . It should be noted that the angled faces of the serrations allow the tubing  38  to slide onto the serrated grip  32  with relative ease, whereas the opposing flat faced walls prevent the tubing  38  from slipping off the serrated grip  32  by discouraging movement in the opposite direction. In order to attach the tubing  38  to the tail piece  28  more securely and to provide a fluid-tight seal, a ferrule  42  having serrations  44  is crimped (by a suitable crimping tool (not shown)) around the tubing  38  such that the tubing  38  is gripped between the tail piece serrations  32  and the ferrule serrations  44 . The ferrule  42  also grips around the collar  34  of the tail piece  28  in order to prevent longitudinal movement of the tail piece  28  in relation to the ferrule  42 .  
         [0046]     It will be understood by the skilled reader that in this embodiment the apparatus  10  will only normally have one female end  16  which may attach to the male end  30  of a tail piece  28 ; however by attaching the female-female link  26  to the previously redundant male end  14  of the apparatus  10  it is then possible to connect both ends of the apparatus  10  to a tail piece  28  having a male end  30 . This is done by sliding a female end  16  of the female-female link  26  onto the male end  14  of the right hand most end link  12  as seen in  FIG. 1  and then sliding the other female end  16  onto the male connector  30  in a similar fashion to that previously described for connection of the links  12 .  
         [0047]     The apparatus  10  and flexible tubing  38  can then be connected between suitable fluid ports of subsea equipment in order to provide fluid communication and/or transfer fluids there between.  
         [0048]     With the tubing  38  and the apparatus  10  now connected between the subsea equipment (not shown), when the ambient pressure surrounding the tubing  38  (due to, for example, the hydrostatic head caused by large depth of water above the apparatus  10 ) overcomes the structural rigidity of the tubing  38 , the tubing  38  will tend to collapse. Leaving the possibility of damaging the tubing  38  aside, this is clearly undesirable since fluid flowing through the tubing  38  will be restricted by any collapsed portion. However, in the present invention, the presence of the links  12  within the tubing  38  provides a non collapsible (under the maximum subsea pressure likely to be experienced) structure  10  upon which the tubing  38  may rest. Thus, in the event that the surrounding pressure causes the tubing  38  to collapse, the diameter of the through bore  56  of the apparatus  10  will not decrease due to the structural integrity provided by the links  12  upon which the partially collapsed tubing  38  will rest. It should be noted that it is not necessary for the connections between the links  12  to be fluid tight since any fluid escaping between the male end  14  and female end  16  of the links  12  will remain inside the fluid tight tubing  38 .  
         [0049]     During installation of the apparatus  10  and tubing  38  between the subsea equipment (not shown) and indeed once installed on the subsea equipment, the flexibility of the tubing  38  and the apparatus  10  is desirable since, during installation, a degree of flexibility assists in positioning each end of the apparatus  10  on the subsea equipment. The provision of flexibility by the apparatus  10  will now be described.  
         [0050]     When a bending moment is applied to the apparatus  10  (by, for example, installation equipment or due to movement of the equipment to which the apparatus  10  is connected) the apparatus  10  is able to articulate or flex (best shown in  FIG. 1 ) due to the curved surfaces on the male  14  and female  16  ends of each link  12 . As one link  12  is tilted away from the other, the bead  24  on one side of the link  12  will slide along the radius R g  of the groove  20  toward the limit of the groove  20  nearest the male end  14  of the link  12  until it is arrested by shoulder  52 , and the bead  24  on the opposite side of the link  12  will slide along the groove  20  toward the limit of the groove  20  nearest the female end  16  of the link  12  until it is arrested by shoulder  54 . In other words, the forces exerted on the apparatus  10  by the bending moment are absorbed by the extension of the apparatus  10  on one side (by sliding the bead  24  toward the male end  14 ) and the contraction of the apparatus  10  on the other side (by sliding the bead  24  toward the female end  16 ). In this way the closely fitting surfaces of the male  14  and female  16  ends can be considered to be similar to that of a ball socket in that movement (typically around 6 degrees though more may be possible if required) of one link  12  with respect to another link  12  is possible in every angular direction. Moreover, the movement is stable movement due to the large surface area of constant contact between sliding surfaces  18  and  22 .  
         [0051]     It should be understood that the apparatus  10  may be used to transfer any fluid, for example drilling fluid, hydraulic fluid, production fluid, cooling fluid etc. The outer diameter of the links  12 ,  26  is typically slightly less than the internal diameter of the flexible tubing/hose  38  it is intended to support. For example, if the internal diameter of the flexible hose is 4″, the external diameter of the links  12 ,  26  may be 3.95″. A preferred length of link  12 ,  26  is in the region of 3.5″ but the links  12 ,  26  could be longer or shorter than this as required. A suitable number of links  12 ,  26  will be used for the particular flexible hose  38  to be supported; typically, such flexible hoses could be in the region of a few meters in length but could be longer than this if required.  
         [0052]     The apparatus  10  therefore provides a flexible tubing system which allows transfer of fluid there along and which cannot collapse due to the pressure of its surrounding environment.  
         [0053]     Referring to  FIGS. 6   a  and  6   b , alternative but less preferred embodiments of the apparatus will now be described.  
         [0054]     Apparatus  110  ( FIG. 6   a ) has tubular links  112  which fit into one another via male  114  and female  116  connection sockets. This embodiment provides the rigidity required for the presently described application; however, the nature of the connection provided by the male  114  and female  116  connection sockets does not as easily allow angular displacement of one end of the apparatus  110  with respect to the other as required in order to maintain the flexibility of the system. Therefore this embodiment is less preferable to that previously described.  
         [0055]     Apparatus  1110  ( FIG. 6   b ) is a further alternative but less preferred embodiment and has tubular links  1112  which fit into one another via male  1114  and female  1116  connection sockets. Once the male socket  1114  is inserted into the female socket  1116 , a wire W is inserted into the gap between the male  1114  and female  1116  sockets via a wire insertion hole  50 . When inserted, the wire W extends around the circumference of the link  1112  and prevents the male  1114  socket from being withdrawn from the female  1116  socket. When disconnection of the links  1112  is desired, the wire W is removed via the hole  50  and the female socket  1116  may then be retracted from the female socket  1114 . As for the apparatus  110  shown in  FIG. 6   a , this embodiment provides the rigidity required for the presently described application; however, the nature of the connection provided by the male  1114 , female  1116  connection sockets and wire W does not as easily allow angular displacement of one end of the apparatus  1110  with respect to the other as required in order to maintain the flexibility of the system. Therefore this embodiment is less preferable.  
         [0056]     Modifications and improvements may be made to the embodiments hereinbefore described without departing from the scope of the invention, for example:  
         [0057]     The preferred embodiment described includes a number of male-female links  12  along the majority of the length of the apparatus  10  which are then connected to tail pieces  28  via female-female links  26  for subsequent connection to a separate components. However, it would be possible to alternately arrange female-female links  26  with male-male links (not shown). This has the advantage that a similar quantity of male-male and female-female links  26  would be required in order to construct the apparatus  10  and there may be manufacturing advantages in providing such a system.