Abstract:
A termination and anchorage for steel helical segmented steel tubing bundles includes a set of multiple separable anchor blocks to which the individual tubes in the bundle can be attached and a clamp assembly for securing and supporting the set of anchor blocks. Multiple comating annular arcuate outer anchor blocks for the outer tubes in the tubing bundle surround a central anchor block, for the center tube in the tubing bundle. The aggregation of anchor blocks is compactly assembled and held together by surrounding the assembled blocks with a separable clamp assembly.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application, pursuant to 35 U.S.C. 111(b), claims the benefit of the filing date of provisional application Ser. No. 60/616,802 filed Oct. 7, 2004, and entitled “Segmented Steel Tube Bundle Termination.” 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field Of The Invention  
         [0003]     The present invention relates in general to a method and apparatus for connectors for subsea operations. More particularly, the invention relates to the termination and axial anchorage of helical steel control tubing bundles used for control lines for subsea wellheads in petroleum production.  
         [0004]     2. Description of the Related Art  
         [0005]     Helical tubing bundles composed of a multiplicity of steel tubes are used routinely for hydraulic control functions and to convey other fluids to subsea wellheads used in petroleum production. The individual tubes are maintained in constant relative angular positions and are arrayed in a bundle in a helical pattern about a central core tube without torsion in the manner used to lay a torsionally balanced wire cable or fiber rope. These relatively flexible tube bundles in some cases can be subjected to high tensions, particularly during their subsea installation.  
         [0006]     Current means for terminating the ends of the tube bundles are bulky and heavy. Typically, the individual tubes at the end of a bundle are displaced somewhat from the bundle longitudinal axis in order to permit connections to anchorages and other fittings to be made. These currently used end terminations are difficult to assemble, particularly if the tubes are welded into an anchor fitting, since sufficient space between tubes must be provided for the welder to operate. Potted anchorages likewise tend to heavy and bulky.  
         [0007]     There exists a need for an apparatus and method that permits an easily assembled anchorage for subsea tube bundles having high tensile capacity.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention relates in general to a method and apparatus for connectors for subsea operations. More particularly, the invention relates to the termination and axial anchorage of helical steel control tubing bundles used for control lines for subsea wellheads in petroleum production.  
         [0009]     The present invention provides a novel type of termination and anchorage for steel helical control tubing bundles. The present invention includes a set of multiple separable anchor blocks to which the individual tubes in the bundle can be attached and a clamp assembly for securing and supporting the set of anchor blocks.  
         [0010]     One aspect of the present invention has a central anchor block, for the center tube in the tubing bundle, surrounded by multiple comating annular arcuate outer anchor blocks for the outer tubes in the tubing bundle. The aggregation of anchor blocks is compactly assembled and held together by surrounding the assembled blocks with a separable clamp assembly. The separability of the anchor blocks permits maximum access to the attachment points of the tubing to the anchors, while at the same time allowing the tubings to be supported on minimal center-to-center spacings.  
         [0011]     Another aspect of the present invention is  
         [0012]     The foregoing has outlined rather broadly several aspects of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed might be readily utilized as a basis for modifying or redesigning the structures for carrying out the same purposes as the invention. It should be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:  
         [0014]      FIG. 1  is an oblique view of the inlet/outlet end of a first embodiment of a tubing termination providing an anchorage for ten steel tubes.  
         [0015]      FIG. 2  shows the tubing termination of  FIG. 1  from its second side where the tubing bundle is attached.  
         [0016]      FIG. 3  is an oblique exploded view of the tubing termination of  FIGS. 1 and 2 .  
         [0017]      FIG. 4  is an axial plan view of the tubing termination of  FIGS. 1, 2 , and  3 , taken from the first side.  
         [0018]      FIG. 5  is a longitudinal sectional view of the tubing termination of FIGS.  1  to  4 , wherein the section is taken along line  5 - 5  in  FIG. 4 .  
         [0019]      FIG. 6  shows an oblique view of the tubing termination of  FIG. 1  mounted on a bend limiter device.  
         [0020]      FIG. 7  is a longitudinal section through the axis of the tubing termination and bend limiter of  FIG. 6 .  
         [0021]      FIG. 8  is an axial view from the first side of a second embodiment of the tubing termination of the present invention.  
         [0022]      FIG. 9  shows an oblique exploded view of the tubing termination of  FIG. 8 .  
         [0023]      FIG. 10  is a longitudinal sectional view of the tubing termination of  FIGS. 8 and 9 , taken along the line  10 - 10  in  FIG. 8 .  
         [0024]      FIG. 11  is a plan view of a third embodiment of the tubing bundle termination of the present invention.  
         [0025]      FIG. 12  is a vertical sectional view taken along line  12 - 12  of the tubing bundle termination shown in  FIG. 11 .  
         [0026]      FIG. 13  is an oblique view of the tubing bundle termination shown in  FIGS. 11 and 12 .  
         [0027]      FIG. 14  is a longitudinal sectional view of a conical tubing anchor of the third embodiment of the tube bundle termination of the present invention.  
         [0028]      FIG. 15  is an oblique view of a typical helical tubing bundle consisting of seven equisized tubes.  
         [0029]      FIG. 16  is an oblique view of a fourth embodiment of the tubing bundle termination of the present invention.  
         [0030]      FIG. 17  is an oblique exploded view of the tubing bundle termination of  FIG. 16 .  
         [0031]      FIG. 18  is a plan view taken from the inlet/outlet side of the tubing bundle termination of  FIGS. 16 and 17 .  
         [0032]      FIG. 19  is a longitudinal sectional view taken along line  19 - 19  of  FIG. 18 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]     The present invention provides an apparatus and method that permits an easily assembled anchorage for subsea tube bundles having high tensile capacity.  
         [0034]     The tubing terminations are intended for use with tubing bundles composed of a multiplicity of steel tubes, wherein the individual tubes are maintained in constant relative angular positions and are arrayed in a bundle in a helical pattern without torsion. In such a tubing bundle, a center tube serves as a core and multiple other tubes are arrayed around the central tube by bending. The tubes need not all be the same size. Normally, the center tube is the largest of the tubes in the bundle. The tubes at an end of a section of a tubing bundle are terminated by means of the tubing terminations of the present invention. Connections are made by either mechanical means or by arc welding. However, in the drawings for the present invention, only welded connections between the bundle tubes and the terminations are shown.  
         [0035]     The components of the main structural elements of the tubing termination embodiments of the present invention are typically made of carbon steel, high-strength/low-alloy steel, or stainless steel. A first embodiment  10  of the tubing termination is shown in FIGS.  1  to  5 .  
         [0036]     Referring to  FIGS. 1 and 2 , the upper and lower sides of the tubing termination  10  are shown. As shown in the drawings, the upper side of the termination corresponds to the inlet or outlet side for the anchored tube bundle, while the lower side is where the tubes of the bundle are attached by welding. Strictly for providing a representative example, the tubing bundle in this case consists of ten equisized tubes, with a single center tube  91  and nine outer tubes  92 . A greater or lesser number of tubes could be utilized, and the sizes can differ for the individual tubes in a particular bundle.  
         [0037]      FIG. 15  shows a typical tubing bundle  90  with a straight core tube  91  and six helically spiraled tubes  92  closely arrayed around the core tube. For this tubing bundle  90  shown in  FIG. 15 , all seven tubes are of the same size.  
         [0038]     The tubing termination  10  consists of a set of comating anchor blocks  11  and  20 , as well as a split clamp assembly  30  which holds the anchor blocks together. The center anchor block  11  supports the center tube  91  of the bundle is a right circular cylinder having a transverse upper flange  12  and a coaxial right circular through hole  13 . The outer cylindrical surface  14  of the center anchor block  11  is comateable with the outer anchor blocks  20  that serve to support the outer tubes  92  in the tube bundle  90 .  
         [0039]     The inlet/outlet end  15  of the center tube  91  of the bundle  90  has a right circular cylindrical external upset having at its lower end a conical transition to the normal outer diameter of the center tube. The external upset diameter is a slip fit to the through hole of the center anchor block. Here, the bore of the inlet/outlet end  15  matches the bore of the center tube  91 . The inlet/outlet end  15  is welded to each of the upper and lower transverse ends of the anchor block  11  by circumferential fillet welds  17 . The inlet/outlet end  15  is attached to the center tube  91  by a circumferential butt or groove weld (not shown for clarity). Here, the other, upper side of the end  15  is identical to the lower side end and attachment by a circumferential butt or groove weld is made there to a tube of equal size to that of the center tube  91 . Alternatively, either or both of the connections could be made by commercially available compressive tube fittings.  
         [0040]     Each outer anchor block  20  is an arcuate segment of an annular right circular cylindrical having an outwardly extending upper transverse flange  21 , a right circular partial cylindrical inner face, a symmetrically positioned right circular through hole  29  parallel to the axis of anchor block  20 , and a right circular partial cylindrical outer face  23 . The radius of the inner face  22  has the same radius as and is comateable with the outer cylindrical surface  14  of the center anchor block  11 . The upper transverse face of the outer anchor block  20  abuts the lower side of the upper flange  12  of the center anchor block  11  when the tubing termination is assembled. In the example shown here, all of the outer anchor blocks  20  are the same since the outer tubes  92  of the bundle  90  all have the same size.  
         [0041]     A symmetrically positioned right circular through bolt hole  24  with its axis parallel to the longitudinal axis of the outer anchor block  20  and extending through upper flange  21  mounts downwardly extending hex-head retainer screw  25 . The planar lateral sides  28  of outer anchor block  20  can be coplanar with the axis of rotation of the block. Alternatively, as shown herein, the individual outer anchor blocks  20  can be made by cutting a solid annular ring with radial saw cuts which have a finite kerf width. The number of outer anchor blocks  20  corresponds to the number of outer tubes  92  in the tubing bundle  90 .  
         [0042]     The inlet/outlet end  27  for the attached outer bundle tube  92  supported by outer anchor block  20  is structurally identical to the inlet/outlet end  15  for the center tube  91 . Circumferential butt or groove welds again make the connections of the inlet/outlet end  27  to the tube  92  and the tube on the opposed end. The inlet/outlet end  27  has a close slip fit to the through hole  29  and is attached to the upper and lower transverse faces of the anchor block by circumferential fillet welds  26 . Again, either or both of the connections alternatively could be made by commercially available compressive tube fittings.  
         [0043]     The split clamp assembly  30  consists of first clamp half  31 , second clamp half  40 , and the clamp studs  50  with clamp nuts  51  required to draw the clamp halves together. Sufficient space is provided between the clamp halves  31  and  40  so that they do not abut prior to fully clamping together the assembled anchor blocks  11  and  20 . The split clamp assembly  30  surrounds and retains the center anchor block  11  and its surrounding set of outer anchor blocks  20 .  
         [0044]     The first clamp half  31  and the second clamp half  40  are identical except for their respective patterns of drilled and tapped retainer screw holes  34 . The arrangements of retainer screw holes are unequal for the clamp halves in this case because there are an odd number of outer anchor blocks  20 . In cases where the number of outer anchor blocks is even, then the hole patterns of both clamp halves and hence the clamp halves  31  and  40  themselves are identical.  
         [0045]     Each clamp half  31  and  40  has a right circular nearly semicylindrical annular body with the diameters greater than the axial length, an externally extending transverse upper reinforcing flange  33  and  43  respectively, and an externally extending transverse lower reinforcing flange  35 . Drilled and tapped with their hole axes parallel to the axis of the clamp and into the upper transverse faces of the clamp halves  31  and  40  are multiple retainer screw holes  34 . The number of retainer screw holes  34  is equal to the number of outer anchor blocks  20 . The inner nearly semicylindrical faces  36  of the clamp halves  31  and  40  are close fits to the outer partial cylindrical faces  23  of the outer clamp blocks  20 . The upper transverse faces of the clamp halves abut the lower transverse faces of the upper flanges  21  of the outer anchor blocks  20 , while the retainer screws  25  are threadedly engaged with the retainer screw holes to mount the outer clamp blocks  20  to the clamp halves.  
         [0046]     Extending outwardly parallel to and slightly offset from the diametrical plane perpendicular to the vertical plane of symmetry for each clamp half  31  and  40  are thick rectangular clamping ears  37 . On each clamping ear, two through clamping bolt holes  38  are drilled horizontally perpendicular to the inner face of the clamping ears  37  symmetrically about the horizontal midplane of the clamp halves. When the clamp halves  31  and  40  are assembled around the anchor blocks  11  and  20 , the clamp studs  50  are extended through the clamping bolt holes  38  and then clamp nuts  51  are used to draw the clamp halves together so that the tubing termination  10  is rigidized.  
         [0047]      FIGS. 6 and 7  show how the tubing termination  10  can be attached to a bend limiting assembly  60  so that the tube bundle  90  will not be overstressed by minor rotations at its anchorage  10 . The bend limiter assembly  60  is a simple ball and socket arrangement with an integral abuttable flange travel stop  84  that serves to limit the amount of rotation of the assembly. The tubing termination  10  can be mounted on the ball or swivel head  80  portion of the bend limiting assembly  60 . The bend limiter assembly  60  consists of a lower socket  61 , two identical retainer halves  70 , and the swivel head  80 .  
         [0048]     The lower socket  61  is a thick right circular cylindrical annular disk with an outwardly protruding transverse flange  63  and an interior cavity, both on its upper side. Flange  63  has a regular bolt hole circle pattern of transverse through holes in its periphery. The interiorcavity on its lower side has a coaxial spherically shaped cup  62  bore, wherein the center of the spherical cup is located at the transverse upper shoulder  65  of the lower socket  61 . An annular open-sided groove detent recess  64  having a vertical outer side and a transverse bottom shoulder is located at the interior edge of the upper shoulder  65 .  
         [0049]     Two identical retainer halves  70  are formed by separating a modified lower socket assembly  61  into two segments with a diametrical cut. These retainer halves are mounted in mirror image positions inverted relative to the lower socket  61  and are retained by studs  87  and hex nuts  88  through the bolt holes in the flange  76  and the comating bolt holes in the flange  63  of the lower socket. However, instead of having a detent recess  64  on its lower shoulder  77  that is equivalent to the upper shoulder  65  of the lower socket  61 , the retainer halves have a male boss  71  which is comateable with the detent recess  64 . Thus, the retainer halves  70  each have a spherical cup  72 , a flange  76 , and a lower shoulder  77 . When mounted together, the retainer halves  70  and the lower socket  61  form a partial spherical pocket that serves as a support for the spherical ball joint mounted in their interior.  
         [0050]     Swivel head  80  is of annular construction and consists of, from its upper end, the following coaxial elements: a transverse right circular annular flange  81 , a thin wall circular tubular neck  83 , and a lower spherical surface  82  with a transverse flange travel stop  84  through its spherical center. The outer diameter of the flange travel stop  84  is sufficiently less than the interior recess of the lower socket  61  and the retainer halves  70  that the swivel head  80  can rotate without contacting the cylindrical interior walls of those parts. The diameter of the spherical surface  82  is comateable with and pivotable within the spherical recess formed by the spherical cups  62  and  72  of the lower socket  61  and the retainer halves  70 , respectively. The upper end of swivel head  80  has a circular through bore  85  extending downwardly from the flange  81  to the center of the spherical surface. Below the center of the spherical surface  82 , the through bore  85  is outwardly flared. The amount of rotation which the swivel head can make about any horizontal axis through the spherical center of the socket formed by the spherical cups  62  and  72  is limited by the engagement of the travel stop  84  with the interior transverse faces of the lower socket  61  and the retainer halves.  
         [0051]     On the upper transverse face of the flange  81  are mounted two mirror image upwardly projecting mounting projections  86 . These mounting projections have vertical coplanar mounting faces that are offset from the vertical axis of the swivel head  80 . The amount of offset of these mounting faces is equal to the amount of offset of the back side of the clamping ears  37  of the split clamp assembly  30 . Drilled and tapped horizontal axis holes are provided in the mounting projection coplanar faces so that the clamp studs  50  of the split clamp assembly can be engaged therein and the tubing termination  10  thereby mounted to the mounting projections.  
         [0052]      FIGS. 8, 9 , and  10  show a second embodiment  100  of the tube bundle termination of the present invention. This second embodiment uses a conical socket in its clamp ring  130  to engage frustroconical surfaces in its outer anchor blocks  120 , while the center anchor block  111  is retained by the engagement of its exterior frustroconical surfaces with comating surfaces on the interior side of the outer anchor blocks. As seen best in  FIGS. 9 and 10 , the center anchor block  111  is a cylinder with transverse end surfaces, an axial through bore  113 , and an outer frustroconical surface  114  having a low taper angle. The center bundle tube  91  is welded with a butt or groove weld to the inlet/outlet end  15  for the tube. The inlet/outlet end  15  has a slip fit within the through bore  113  and is retained therein by means of upper and lower circumferential fillet welds  17  at the penetration of the inlet/outlet end through the transverse faces of the anchor block  111 .  
         [0053]     The outer anchor blocks  120  are angular segments cut from an annular ring having transverse ends and coaxial inner and outer frustroconical surfaces which taper in the same direction. The inner frustroconical surface has the same taper angle as the outer frustroconical surface  114  of the center anchor block  111 , and these two surfaces are comateable over a substantial portion of their axial length. Thus, each outer anchor block  120  has an inner partial frustroconical surface  122 , an outer partial frustroconical surface  123 , and two planar lateral sides  128  formed by diametrical cuts of the annular ring described above. A through bore  129  extends through the outer anchor block  120  parallel to the frustroconical axis and on the vertical plane of symmetry of the anchor block. An outer bundle tube  92  is welded with a butt or groove weld to the inlet/outlet end  27  for the tube. The inlet/outlet end  27  has a slip fit within the through bore  129  and is retained therein by means of upper and lower circumferential fillet welds  26  at the penetration of the inlet/outlet end through the transverse faces of the anchor block  111 .  
         [0054]     The clamp ring  130  for tubing termination  100  is an annular right circular cylindrical ring having a coaxial inner frustroconical bore  136  which is comateable with the outer partial frustroconical surfaces  123  of the outer anchor blocks  120 . The assembly of the tubing termination  100  thus has the interior bore  136  of the clamp ring  130  filled with one outer anchor block  120  for each outer tube  92  in the tubing bundle  90  to form a complete assemblage of outer anchor blocks to fill the conical cup of the clamp ring. A center anchor block  111  is then positioned in the center frustroconical socket formed by the inner partial frustroconical surfaces  122  of the outer anchor blocks  120 . The taper angles of the frustroconical surfaces of the assemble can be selected to make the tapers either self-releasing or alternatively to have the angle of the comating frustroconical surfaces sufficiently small that the assembled anchor blocks are retained by friction against unintentional release.  
         [0055]     A third embodiment  200  of the tubing termination is similar to the first embodiment  10 , but the inlet/outlet ends  215  and  227  provided for the tubes  91  and  92  in the tube bundle  90  have frustroconical exterior surfaces which are socketed in comating frustroconical bores in the anchor blocks  211  and  220 .  FIGS. 11 through 14  show the details of tube bundle termination  200 .  
         [0056]     As shown in the drawings, the upper side of the termination  200  corresponds to the inlet or outlet side for the anchored tube bundle  90 , while the lower side is where the tubes of the bundle are attached by welding. Strictly for providing a representative example, the tubing bundle in this case consists of seven equisized tubes, with a single center tube  91  and six outer tubes  92 .  
         [0057]     The third embodiment tubing termination  200  consists of a set of comating anchor blocks  211  and  220 , as well as a split clamp assembly  30  which holds the anchor blocks together. The center anchor block  211  that supports the center tube  91  of the bundle is a right circular cylinder having a transverse upper flange  212  and a coaxial frustroconical through hole  213 . The diameter of hole  213  is reduced from top to the bottom end. The outer cylindrical surface  214  of the center anchor block  211  is comateable with the outer anchor blocks  220  that serve to support the outer tubes  92  in the tube bundle  90 . The inlet/outlet end  215  of the center tube  91  of the bundle  90  has a frustroconical external upset with a low angle and a downwardly reducing diameter. The inlet/outlet end  215  has at its lower end a conical transition to the normal outer diameter of the center tube  91 . The external upset frustroconical surface is comateable with the through hole  213  of the center anchor block. Here, the bore of the inlet/outlet end  215  matches the bore of the center tube  91 . The inlet/outlet end  215  is not welded to the anchor block  211 , but is instead retained by frictional engagement. The inlet/outlet end  215  is attached to the center tube  91  by a circumferential butt or groove weld (not shown for clarity). Here, the other, upper side of the end  215  is identical to the lower side end and attachment by a circumferential butt or groove weld is made there to a tube of equal size to that of the center tube  91 . Alternatively, either or both of the connections could be made by commercially available compressive tube fittings.  
         [0058]     Each outer anchor block  220  is an arcuate segment of an annular right circular cylindrical having an outwardly extending upper transverse flange  221 , a right circular partial cylindrical inner face  222 , a symmetrically positioned frustroconical through hole  229  parallel to the axis of anchor block  220 , and a right circular partial cylindrical outer face  223 . The radius of the inner face  222  is comateable with the outer cylindrical surface  214  of the center anchor block  211 . The upper transverse face of the outer anchor block  220  abuts the lower side of the upper flange  212  of the center anchor block  211  when the tubing termination is assembled. As shown here, all of the outer anchor blocks  220  are the same since the outer tubes  92  of the bundle  90  all have the same size. A symmetrically positioned right circular through bolt hole  224  with its axis parallel to the longitudinal axis of the outer anchor block  220  and extending through upper flange  221  mounts downwardly extending hex-head retainer screw  225 . The planar lateral sides  228  of outer anchor block  220  can be coplanar with the axis of rotation of the block. Alternatively, as shown herein, the individual outer anchor blocks  220  can be made by cutting a solid annular ring with radial saw cuts which have a finite kerf width. The number of outer anchor blocks  220  corresponds to the number of outer tubes  92  in the tubing bundle  90 .  
         [0059]     The inlet/outlet end  227  for the attached outer bundle tube  92  supported by outer anchor block  220  is structurally identical to the inlet/outlet end  215  for the center tube  91 . The connections of the inlet/outlet end  227  to the tube  92  and the tube on the opposed end are again made by circumferential butt or groove welds. The inlet/outlet end  227  is firmly comateable with the through hole  229 . Again, either or both of the connections alternatively could be made by commercially available compressive tube fittings.  
         [0060]     A fourth embodiment tubing termination  300 , shown in  FIGS. 17-19 , is in most respects very similar to the first embodiment  10 . The difference resides in the approaches to retaining the tube bundle and its attached inner and outer anchor blocks in the split clamp assembly whenever there is an outward thrust on the bundle. In the case of tubing termination  300 , the anchor blocks  311  and  320  are both restrained in axial motion in either direction by flanges on both ends of the anchor blocks.  
         [0061]     Tubing termination  300  consists of a set of comating anchor blocks  311  and  320 , as well as a split clamp assembly  30  that holds the anchor blocks together. The split clamp assembly is the same in all details as is used for the first embodiment  100 . The center anchor block  311  that supports the center tube  91  of the bundle is a right circular cylinder having a transverse upper flange  312 , a coaxial right circular through hole  313 , and a transverse lower flange  318  that is a mirror image of the upper flange  312 .  
         [0062]     The outer cylindrical surface  314  of the center anchor block  311  is comateable with the outer anchor blocks  320  that serve to support the outer tubes  92  in the tube bundle  90 . The inlet/outlet end  15  of the center tube  91  of the bundle  90  has a right circular cylindrical external upset having at its lower end a conical transition to the normal outer diameter of the center tube. The external upset diameter is a slip fit to the through hole of the center anchor block. Here, the bore of the inlet/outlet end  15  matches the bore of the center tube  91 . The inlet/outlet end  15  is welded to each of the upper and lower transverse ends of the anchor block  311  by circumferential fillet welds  17 . The inlet/outlet end  15  is attached to the center tube  91  by a circumferential butt or groove weld (not shown for clarity). Here, the other, upper side of the end  15  is identical to the lower side end and attachment by a circumferential butt or groove weld is made there to a tube of equal size to that of the center tube  91 . Alternatively, either or both of the connections could be made by commercially available compressive tube fittings.  
         [0063]     Each outer anchor block  320  is an arcuate segment of an annular right circular cylindrical having an outwardly extending upper transverse flange  321 , a right circular partial cylindrical inner face  322 , a symmetrically positioned right circular through hole  229  parallel to the axis of anchor block  320 , a right circular partial cylindrical outer face  323 , and an outwardly extending transverse lower flange  330 . The radius of the inner face  322  has the same radius as and is comateable with the outer cylindrical surface  314  of the center anchor block  311 . The upper transverse face of the outer anchor block  320  abuts the lower side of the upper flange  312  of the center anchor block  311  when the tubing termination is assembled. Likewise, the lower transverse face of the outer anchor block  320  abuts the upper side of the lower flange  318  of the center anchor block  311  when the tubing termination  300  is assembled.  
         [0064]     As shown here, all of the outer anchor blocks  320  are the same since the outer tubes  92  of the bundle  90  all have the same size. The planar lateral sides  328  of outer anchor block  320  can be coplanar with the axis of rotation of the block. Alternatively, as shown herein, the individual outer anchor blocks  320  can be made by cutting a solid annular ring with radial saw cuts which have a finite kerf width. The number of outer anchor blocks  320  corresponds to the number of outer tubes  92  in the tubing bundle  90 .  
         [0065]     The inlet/outlet end  27  for the attached outer bundle tube  92  supported by outer anchor block  320  is structurally identical to the inlet/outlet end  15  for the center tube  91 . The connections of the inlet/outlet end  27  to the tube  92  and the tube on the opposed end are again made by circumferential butt or groove welds. The inlet/outlet end  27  has a close slip fit to the through hole  329  and is attached to the upper and lower transverse faces of the anchor block by circumferential fillet welds  26 . Again, either or both of the connections alternatively could be made by commercially available compressive tube fittings.  
       OPERATION OF THE INVENTION  
       [0066]     The operation of the tube bundle terminations of the present invention is concerned with the assembly of the structures, since the apparatus is stationary and passive following assembly. The characteristic of the tube bundle construction which facilitates the use of the type of structural arrangement used in the present invention is the lack of torsion induced in the individual tubes when the bundle is fabricated. The outer tubes in the bundle are laid into their helical pattern utilizing only bending, rather than torsion, while the center tube is neither bent nor twisted. This causes the maintenance of alignment between the tube ends of the bundle and the elements of the tube bundle termination to be much easier when the anchor blocks of the termination are separated to attach the tubes. Generally, following the attachment of the tube bundle terminations to the tubes, only elastic bending of the separated outer tubes is required to reestablish the desired compact bundle geometry at the end of the bundle.  
         [0067]     The assembly of the tube bundle termination  100  proceeds as follows. The ends of the outer tubes of the bundle at the end of the bundle are separated sufficiently so that there is sufficient room for a welder to operate around any one of the tubes in the bundle. At this point, a circumferential butt or groove weld is made to align and join each of the outer tubes  92  and the inner tube  91  to an outer tube inlet/outlet end  27  or an inner tube inlet/outlet end  15 , respectively. Following this, the inner tube inlet/outlet end  15  and each of the outer tube inlet/outlet ends  27  is slipped into the through bore  13  of center anchor block  1  or the through bore  29  of outer anchor block  20 , as appropriate.  
         [0068]     At this point, the anchor blocks  11  and  20  are reassembled by elastically bending the tubes  92  into their packed pattern as shown in  FIGS. 1, 2 , and  4 . Following this, the split clamp assembly  30  is assembled around the assembled anchor block pattern by engaging the clamp halves  31  and  40  around the anchor blocks and then tightening the nuts  51  on the studs  50  after insertion of the studs through the clamping bolt holes  38 . At this point, match marks between each tube inlet/outlet end  15  or  27  and its corresponding anchor block can be made. Alternatively, tack welds of the tube inlet/outlet ends  15  or  27  with their respective anchor blocks  11  or  20  can be made to hold the desired alignment therebetween. At this point, the clamp assembly  30  can be removed, the anchor blocks reseparated, and the circumferential fillet welds  17  made to rigidly affix the inlet/outlet ends  15  or  27  to their respective blocks. If tack welds were not used to hold alignment, then following anchor block separation, the blocks are aligned with their respective tubes using the marks prior to the making of the final welds  17 .  
         [0069]     When the connecting welds  17  are completed, the anchor blocks  11  and  20  can be reclustered and the assembly completed by clamping the assembly  10  together using the split clamp assembly  30 . At this time, the bolt holes  24  of the outer anchor blocks  20  are aligned with their respective retainer screw holes  34  and  44  in the first clamp half  31  and second clamp half  40 , respectively. Engagement of the retainer screws  25  through the bolt holes  24  and into the retainer screw holes  34  and  44  completes the assembly of the clamp. After this assembly operation, the tube bundle termination  10  is fully rigidized and can resist axial loads in the direction of the tube bundle  90  by abutment of the upper flange  12  of the center anchor block  11  on the upper surface of the outer anchor blocks  20  and the abutment of the upper flange  21  of the outer anchor blocks  20  on the upper surface of the split clamp assembly  30 . The retainer screws  25  and friction between the center anchor block  11  and its surrounding outer anchor blocks  20  provide resistance to axial loads in the other direction.  
         [0070]     If the tubing termination  10  is to be used with the bend limiter assembly  60  shown in  FIGS. 6 and 7 , the split clamp assembly  30  is first removed and the anchor blocks  11  and  20  and tubes  91  and  92  passed through the through bore  85  of the swivel head  80 , assuming that sufficient clearance is available. If the clearance is insufficient, then the bend limiter assembly  60  must be slid over the ends of the tubing bundle prior to welding the inlet/outlet tube ends  15  and  27  to their respective anchor blocks  11  or  20 . After the tubing termination  100  is extended beyond the upper surface  81  of the swivel head  80  of the bend limiter assembly  60 , the flange nuts  51  on one side of the split clamp assembly  30  are removed so that the studs  50  can be engaged into the drilled and tapped holes mounting projections  86  of the swivel head  80  of the bend limiter assembly  60 .  
         [0071]     The assembly of the second embodiment  100  of the tube bundle termination proceeds in a similar manner to that for the first embodiment  10 . For the termination  100 , the clamp ring  130  must be slipped over the end of the tube bundle  90  prior to the final assembly welds  17  being used to join the anchor blocks  111  and  120  to their respective inlet/outlet tube ends  15  and  27 . The assembly of the clamp  130  onto the clustered anchor blocks  111  and  120  is performed by sliding the clamp  130  over the clustered anchor blocks until the inner frustroconical face  136  of the clamp is tightened onto the outer frustroconical surfaces  123  of the outer anchor blocks  120 . At this point, abutment of the frustroconical faces of the anchor blocks  111  and  120  and clamp  130  resists axial loads in the tube bundle direction. Loads in the opposite direction are resisted by friction between the frustroconical faces.  
         [0072]     The assembly of the third embodiment  200  of the tube bundle termination also proceeds similarly to that of the first embodiment  10  with the following exceptions. The third embodiment  200  utilizes frustroconical surfaces between the inlet/outlet tube ends  215  and  227  and their respective anchor blocks  211  and  220  to socket and thereby anchor the inlet/outlet end in the termination  200 . Accordingly, the anchor blocks  211  and  220  must be slipped over the ends of the tubes  91  and  92  of the tube bundle  90  prior to welding of the inlet/outlet tube ends  215  and  227  to their respective tubes by butt or groove circumferential welds. Rotational alignment of the inlet/outlet tube ends is readily achieved without advance fitup or marking, since the inlet/outlet ends  215  and  227  can freely rotate in their respective frustroconical through bores  213  and  229  until pulling them firmly into abutment tightens them. The assembly of the split clamp  30  and the retention in the clamp of the anchor blocks  211  and  220  is identical to that of termination  10 .  
         [0073]     The fourth embodiment of the tube bundle termination  300  is very similar to that of termination  10 . The difference between the two embodiments is related to the means for resisting axial loads produced by thrust on the end of the tube bundle  90 . The tube bundle termination  300  is assembled in a manner identical to that used for the termination  10 . For this embodiment  300  when axial tension is induced in the tube bundle  90 , the upper flange  312  of the center anchor block  311  abuts the upper transverse faces of the outer anchor blocks  320 , while the upper flanges  321  of the anchor blocks  320  abut the upper side of the split clamp assembly  30 . For thrust loads from the tube bundle  90 , the lower flange  318  of the center anchor block  311  abuts the lower transverse faces of the outer anchor blocks  320 , while the lower flanges  330  of the anchor blocks  320  abut the lower side of the split clamp assembly  30 . Note that the retainer screw holes  34  and  44  of the first and second clamp halves  31  and  40 , respectively, can be omitted for this embodiment.  
       ADVANTAGES OF THE INVENTION  
       [0074]     The advantages of the present invention directly result from the ability to physically separate the anchor blocks of the tube bundle terminations by sufficient space that the necessary connecting welds between the tubes  91  and  92  of the tube bundle  90  and their respective inlet/outlet tube ends can be readily made. This ability directly results from the segmentation of the anchor assembly into a set of anchor blocks wherein one block is provided for each tube in the tube bundle. Likewise, if the inlet/outlet tube ends are directly welded to their respective inner and outer anchor blocks, as is the case for tube bundle terminations  10 ,  100 , and  300 , the anchor blocks can be sufficiently separated to permit easily making those welds.  
         [0075]     Because of this ability to separate the anchor blocks, the center-to-center spacing of the tubes in the termination can be decreased significantly, since welding does not have to be done in the inter-tube spaces of the assembled terminations of the present invention. Consequent to the compactness of the present invention, its weight and cost for construction as well as the assembly cost are significantly reduced.  
         [0076]     The present invention provided a more flexible means for terminating tube bundles than conventional welding or potting the tubes into a socket with a plastic. Should there be a problem with one tube, the termination assembly readily can be disassembled, repaired, and reassembled. This flexibility greatly improves the maintainability of the termination.  
         [0077]     The termination  200  can be assembled with particular ease, so that it offers the quickest assembly of the set of terminations of the present invention. For cases of very low thrust loads applied to the termination by the tube bundle, the second embodiment  100  or the third embodiment  200  are satisfactory. The first 10 and, particularly, the fourth embodiment  300  of the present invention offer very high resistance to thrust loads.  
         [0078]     As readily may be understood by those skilled in the art, the present invention may be varied in its details without departing from the spirit of the invention. For example, the configuration of the inlet/outlet tube ends may be varied. Likewise, compression tube fittings may be utilized as an alternative to welded connections between the tubes of the tube bundle and the terminations of the present invention.