Segmented steel tube bundle termination assembly

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] This application is a continuation in part of pending U.S. patent application Ser. No. 11/244,465 (Attorney Docket Number OCEN-P002US), filed Oct. 6, 2005 by inventor David Carter Allensworth and entitled "Termination for Segmented Steel Tube Bundle."

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 includes a subsea termination device for a helical tubing bundle comprising: a) a center anchor block attached to a center tube of a tubing bundle; b) a plurality of outer anchor blocks surrounding the inner anchor block, each outer anchor block attached to an outer tube of the tubing bundle, wherein each outer anchor block has an interior surface abutting an outer surface of the center anchor block and an exterior surface; and c) a selectably removable clamp, wherein the clamp surrounds and engages the exterior surface of the outer anchor blocks.

[0011] Another aspect of the present invention is a termination device comprising: a) an anchor block assemblage having a center anchor block attached to a center tube of a tubing bundle, a plurality of outer anchor blocks surrounding the center anchor block wherein each outer anchor block has an interior surface comateable with an outer surface of the center anchor block; b) a ring clamp engageable around the anchor block assemblage to thereby rigidize the anchor block assemblage; and c) a retaining means for restraining the axial motion of the center and outer anchor blocks.

[0012] Yet another aspect of the present invention A termination device comprising: a) an anchor block assemblage having a center anchor block attached to a center tube of a tubing bundle, a plurality of outer anchor blocks surrounding the center anchor block wherein each outer anchor block has an interior surface comateable with an outer surface of the center anchor block; b) a ring clamp engageable around the anchor block assemblage to thereby rigidize the anchor block assemblage; and c) a retaining means for restraining the axial motion of the center and outer anchor blocks.

[0013] 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

[0014] 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:

[0015] FIG. 1 is an oblique view of the first embodiment of the tubing termination of the present invention, wherein a tubing bundle consisting of ten steel tubes is anchored. The tubing termination is shown from its first side which serves as the inlet/outlet end for the tubing bundle.

[0016] FIG. 2 is an exploded view of the tubing termination of FIG. 1.

[0017] FIG. 3 is a longitudinal quarter sectional view of the center tubing anchor block of the tubing termination of FIGS. 1 and 2.

[0018] FIG. 4 is a side profile view of an outer anchor block taken normal to a plane through the axis of symmetry of the tubing termination of FIGS. 1, 2, and 3.

[0019] FIG. 5 is an oblique profile view of a split clamp half for the tubing termination of FIG. 1.

[0020] FIG. 6 shows a plan view of the assembled tubing termination of FIG. 1.

[0021] FIG. 7 is a longitudinal section taken along section line 7-7 of FIG. 6 through the axis of symmetry of the first embodiment of the tubing termination.

[0022] FIG. 8 is an oblique view of a second embodiment of the tubing termination of the present invention.

[0023] FIG. 9 is an oblique exploded view of the tubing termination of FIG. 8.

[0024] FIG. 10 is a plan view of the tubing termination of FIGS. 8 and 9.

[0025] FIG. 11 is a longitudinal cross-sectional view of the second embodiment of the tubing termination taken along section line 11-11 of FIG. 10.

[0026] FIG. 12 is an oblique view of a typical helical tubing bundle consisting of seven equisized tubes.

[0027] FIG. 13 is a partially exploded view of the first embodiment of the tubing termination with a first type of mounting structure.

[0028] FIG. 14 is a partially exploded view of the first embodiment of the tubing termination with a second type of mounting structure.

[0029] FIG. 15 is an oblique view of the first embodiment of the tubing termination assembled with the first type of mounting structure shown in the exploded view of FIG. 13.

[0030] FIG. 16 is an oblique view of the first embodiment of the tubing termination assembled with the second type of mounting structure shown in the exploded view of FIG. 14.

[0031] FIG. 17 is an longitudinal quarter sectional view of an alternative center tubing anchor block and tube attachment means for use in the tubing termination of FIGS. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The present invention provides an apparatus and method that permits an easily assembled anchorage for subsea tube bundles having high tensile capacity.

[0033] 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, although for simplicity the tubes shown in the drawings are all 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.

[0034] 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 7.

[0035] Referring to FIGS. 1 and 2, the tubing termination 10 is shown in an oblique view and an oblique exploded view. 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 90 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.

[0036] FIG. 12 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. 12, all seven tubes are of the same size.

[0037] The first embodiment of the tubing termination 10 includes a set of anchor blocks containing a single center anchor block 11 and multiple comating outer anchor blocks 30, as well as a split clamp assembly 50 which holds the assemblage 48 of anchor blocks together. The center anchor block 11 which supports the center tube 91 of the bundle is a right circular cylindrical tube having a transverse upper face 12, a coaxial right circular through hole 13, an outer cylindrical surface 14, and a transverse lower face 15. A large chamfer is positioned at the lower end of the anchor block 11 at the intersection of the outer cylindrical surface 14 and the lower transverse face 15. Centrally located in the middle of the outer cylindrical surface 14 is a right circular cylindrical coaxial reduced diameter central portion 16 of the center anchor block 11. The reduced diameter central portion 16 is connected to the upper and lower sections of the outer cylindrical surface 14 by upper frustroconical shoulder 17 and lower frustroconical shoulder 18, respectively. The frustroconical shoulder surfaces are inclined from the axis of the center anchor block 11 by similar angles in the range of 30.degree. to 60.degree..

[0038] The inlet/outlet end 95 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 of the inlet/outlet end 95 is a slip fit to the through hole 13 of the center anchor block 11. The inlet/outlet end 95 is welded to each of the upper 12 and lower 15 transverse faces of the anchor block 11 by circumferential fillet welds 19. The inlet/outlet end 95 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 or to a socket weld fitting.

[0039] Each outer anchor block 30 is an arcuate segment of an annular right circular cylindrical having an upper transverse face 31, a right circular partial cylindrical inner face 32, a symmetrically positioned right circular through bore 42 parallel to the axis of anchor block 30, a lower transverse face 36, and a right circular partial cylindrical outer face 37. The radius of the inner face 32 has the same radius as and is comateable with the outer cylindrical surface 14 of the center anchor block 11. Centrally located in the middle of the inner cylindrical surface 32 is a right circular cylindrical coaxial reduced diameter inner central section 33 of the outer anchor block 30. The reduced diameter central portion 33 is connected to the upper and lower sections of the inner cylindrical surface 32 by inner upper frustroconical shoulder 34 and inner lower frustroconical shoulder 35, respectively. The frustroconical shoulder surfaces 34 and 35 are inclined from the axis 20 of the outer anchor block 30 by the same angle as are the frustroconical shoulders 17 and 18 of the center anchor block 11 so that the shoulders 34 are comatable with the shoulder 17 and the shoulders 35 are comatable with the shoulder 18. The diameter of the reduced diameter central portion 33 is the same as or slightly larger than the diameter of the reduced diameter central portion 16 of the center anchor block 11 in order to permit the mating of the frustroconical faces. The outer anchor blocks 30 are able to mate with the center anchor block 11 so that the inner cylindrical surfaces 32 of the outer anchor blocks abut the outer cylindrical surface 14 of the center anchor block.

[0040] Centrally located in the middle of the outer cylindrical surface 37 of the outer anchor block 30 is a right circular cylindrical coaxial reduced diameter central portion 38. The reduced diameter central portion 38 is connected to the upper and lower sections of the outer cylindrical surface 37 by outer upper frustroconical shoulder 39 and outer lower frustroconical shoulder 40, respectively. The frustroconical shoulder surfaces are inclined from the axis 20 of the outer anchor block 30 by similar angles in the range of 30.degree. to 60.degree..

[0041] As shown here, all of the outer anchor blocks 30 are the same since the outer tubes 92 of the bundle 90 all have the same size. The planar lateral sides 43 of outer anchor block 30 can be coplanar with the axis of rotation 20 of the block and of the overall anchor block assemblage 48. Alternatively, as shown herein, the individual outer anchor blocks 30 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 30 corresponds to the number of outer tubes 92 in the tubing bundle 90.

[0042] The inlet/outlet end 96 for the attached outer bundle tube 92 supported by outer anchor block 30 is structurally identical to the inlet/outlet end 95 for the center tube 91. The connections of the inlet/outlet end 96 to the tube 92 and the tube on the opposed end are typically made by circumferential butt or groove welds (not shown herein for clarity). The inlet/outlet end 96 has a close slip fit to the through bore 42 and is attached to the upper 31 and lower 36 transverse faces of the anchor block 30 by circumferential fillet welds 44. Again, either or both of the connections alternatively could be made by commercially available compressive tube fittings or socket weld fittings.

[0043] The split clamp assembly 50 consists of a pair of clamp halves 51 and the clamp studs 64 with clamp nuts 65 required to draw the clamp halves together. Sufficient space is provided between the clamp halves 51 so that they do not abut prior to fully clamping together the assemblage 48 of anchor blocks 11 and 30. The split clamp assembly 50 surrounds and retains the anchor block assemblage 48 consisting of the center anchor block 11 and its surrounding set of outer anchor blocks 30. The clamp halves 51 each have a right circular nearly semicylindrical annular body 52 with its diameters greater than its axial length. At the upper transverse side of each clamp half, an outwardly extending nearly semiannular transverse upper reinforcing flange 53 is located, with a mirror image transverse lower reinforcing flange 54 located at the lower transverse side.

[0044] For the first embodiment of the tubing termination 10, the inner side of a clamp half 51 has an inner nearly semicylindrical face 56 with a symmetrically positioned inner reduced diameter semicylindrical face 57 at its midheight. Mirror-image frustroconical shoulders 58 and 59 cojoin the two nearly semicylindrical faces 56 and 57. The inner nearly semicylindrical face 57 is a close fit to the outer cylindrical surface sections 37 of the assembled group of outer anchor blocks 30. The upper frustroconical shoulder 58 of the clamp half 51 has the same slope as the outer upper frustroconical shoulder 39 of the outer anchor blocks 30 so that the two shoulders are comatable. Likewise, the lower frustroconical shoulder 59 of the clamp half 51 is similarly comatable with the outer lower frustroconical shoulder 40 of the outer anchor blocks 30. The inner reduced diameter semicylindrical face 57 of the clamp half has a diameter equal to or greater than the diameter of the outer reduced diameter central section 38 of the outer anchor blocks 30.

[0045] Extending outwardly parallel to and slightly offset from the diametrical plane perpendicular to the vertical plane of symmetry for each clamp half 51 on each side are thick rectangular clamping ears 60. On each clamping ear 60, two through clamping bolt holes 61 are drilled horizontally perpendicular to the inner face of the clamping ears and placed symmetrically about the horizontal midplane of the clamp half. When the clamp halves 51 are assembled around the anchor blocks 11 and 30, the clamp studs 64 are extended through the clamping bolt holes 61 and then clamp nuts 65 are used to draw the clamp halves together so that the tubing termination 10 is rigidized. At assembly, the upper 17 and lower 18 frustroconical shoulders of the center anchor block 11 respectively can bear on the comatable inner upper 34 and inner lower 35 frustroconical shoulders of the outer anchor blocks 30. At the same time, the outer upper 39 and outer lower 40 frustroconical shoulders of the outer anchor blocks 30 respectively can bear against the inner upper 57 and lower 58 frustroconical shoulders of the clamp halves 51 of the assembled split clamp assembly 50.

[0046] The second embodiment tubing termination 100, shown in FIGS. 8 through 11, is in most respects very similar to the first embodiment 10. The difference resides in the approaches to retaining the tube bundle 90 and its attached assemblage 110 of one inner 111 and the outer 130 anchor blocks in the split clamp assembly 150 whenever there is an compressive thrust on the tube bundle. In the case of tubing termination 100, the anchor blocks 111 and 130 are both restrained in axial motion in either direction by flanges on both ends of the anchor blocks.

[0047] Referring particularly to FIGS. 9 and 11, tubing termination 100 is seen to consist of a set of comating anchor blocks 111 and 130, as well as a split clamp assembly 150 that holds the anchor blocks together. The split clamp assembly is the same in most details as is used for the first embodiment 10. The center anchor block 111 supports the center tube 91 of the tube bundle 90. The center anchor block 111 is a right circular cylinder having a transverse upper flange 112, a coaxial right circular through hole 113, and a transverse lower flange 118 which is a mirror image of the upper flange 112. The outer cylindrical surface 114 of the center anchor block 111 is comateable with the outer anchor blocks 130 that support the outer tubes 92 in the tube bundle 90.

[0048] The inlet/outlet end 95 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 113 of the center anchor block 111. Here, the bore of the inlet/outlet end 95 matches the bore of the center tube 91. The inlet/outlet end 95 is welded to each of the upper and lower transverse ends of the anchor block 111 by circumferential fillet welds 19. The inlet/outlet end 95 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 95 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.

[0049] Each outer anchor block 130 is an arcuate segment of an annular right circular cylinder having an outwardly extending upper transverse flange 131, a right circular partial cylindrical inner face 132, a symmetrically positioned right circular through bore 142 parallel to the rotational axis of symmetry 120 of anchor block 130, a right circular partial cylindrical outer face 137, and an outwardly extending transverse lower flange 136. The radius of the inner face 132 has the same radius as and is comateable with the outer cylindrical surface 114 of the center anchor block 111. The upper transverse face of the outer anchor block 130 abuts the lower side of the upper flange 112 of the center anchor block 111 when the tubing termination is assembled. Likewise, the lower transverse face 136 of the outer anchor block 130 abuts the upper side of the lower flange 118 of the center anchor block 111 when the tubing termination 100 is assembled. As shown here, all of the outer anchor blocks 130 are the same since the outer tubes 92 of the bundle 90 all have the same size.

[0050] The planar lateral sides 143 of outer anchor block 130 can be coplanar with the axis of rotation 120 of the block. Alternatively, as shown herein, the individual outer anchor blocks 130 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 130 corresponds to the number of outer tubes 92 in the tubing bundle 90.

[0051] The inlet/outlet end 96 for the attached outer bundle tube 92 supported by outer anchor block 130 is structurally identical to the inlet/outlet end 95 for the center tube 91. The connections of the inlet/outlet end 96 to the tube 92 and the tube on the opposed end are again made by circumferential butt or groove welds (not shown for clarity). The inlet/outlet end 96 has a close slip fit to the through bore 142 and is attached to the upper 131 and lower 136 transverse flanges of the anchor block by circumferential fillet welds 44. Again, either or both of the connections alternatively could be made by commercially available compressive tube fittings.

[0052] The split clamp assembly 150, seen best in FIGS. 8 and 9, consists of a pair of clamp halves 151 and the clamp studs 64 with clamp nuts 65 required to draw the clamp halves together. Sufficient space is provided between the clamp halves 151 so that they do not abut prior to fully clamping together the assemblage 110 of anchor blocks 111 and 130. The split clamp assembly 150 surrounds and retains the anchor block assemblage 110 consisting of the center anchor block 111 and its surrounding set of outer anchor blocks 130. The clamp halves 151 each have a right circular nearly semicylindrical annular body 152 with its diameters greater than its axial length. At the upper transverse side of each clamp half, an outwardly extending nearly semiannular transverse upper reinforcing flange 153 is located, with a mirror image transverse lower reinforcing flange 154 located at the lower transverse side.

[0053] For the second embodiment of the tubing termination 100, the inner side of a clamp half 151 has an inner nearly semicylindrical face 156 extending its full height. The inner nearly semicylindrical face 156 is a close fit to the outer cylindrical surface sections 137 of the assembled group of outer anchor blocks 130. The height of the split clamp half 151 is such that it is a close fit between the inside faces of the upper 131 and lower 136 transverse flanges of the outer anchor blocks 130.

[0054] Extending outwardly parallel to and slightly offset from the diametrical plane perpendicular to the vertical plane of symmetry for each clamp half 151 on each side are thick rectangular clamping ears 160. On each clamping ear 160, two through clamping bolt holes 161 are drilled horizontally perpendicular to the inner face of the clamping ears and placed symmetrically about the horizontal midplane of the clamp half. When the clamp halves 151 are assembled around the anchor blocks 111 and 130, the clamp studs 64 are extended through the clamping bolt holes 61 and then clamp nuts 65 are used to draw the clamp halves together so that the tubing termination 100 is rigidized. At assembly, the upper 112 and lower 118 flanges of the center anchor block 111 respectively bear on the outer transverse ends of the upper 131 and lower 136 flanges of the outer anchor blocks 130. At the same time, the inner sides of the upper 131 and lower 136 transverse flanges of the outer anchor blocks 130 respectively bear against the upper and lower transverse ends of the clamp halves 151 of the assembled split clamp assembly 150.

[0055] It is generally necessary to mount the tubing terminations for helical tube bundles so that the tube bundles are supported against lateral and axial displacements. A wide array of types of supports are used for various applications, but two types are shown herein in FIGS. 13 to 16 by way of example so that the mounting arrangements for the first and second tubing terminations can be described. The first embodiment 10 of the tubing termination is shown in FIGS. 13 to 16 for illustration purposes, but the second embodiment 100 could likewise be used, since the split clamp assemblies 50 and 150 are substantially structurally identical in most respects.

[0056] Referring to FIG. 13, the first mounting 200 consists of a short right circular tubular section 202 with an outwardly extending transverse right circular cylindrical annular flange 201 at its upper end. The flange 201 has a frustroconical transition section between its lower side and the exterior of the tubular section 202 to reduce stress concentrations between the two primary elements. The first mounting 200 has a right circular cylindrical coaxial through hole 203 extending vertically through its length. The diameter of the through hole 203 is selected to be such that the tubing bundle 90 can readily pass through the hole. If so desired, the diameter of the through hole 203 can be made sufficiently large that it can pass the assembled anchor block assemblage 48 of the first tubing termination embodiment 10 or the assembled anchor block assemblage 110 of the second tubing termination 100. However, the size of hole 203 should not be so large that at least a portion of the nearly semicylindrical transverse end of the split clamp assembly 50 or 150 would not bear on the flange 201 when the clamp assembly is concentrically mounted on the mounting 200. The mounting 200 typically would be attached to a supporting structure by the welding of the lower end of its tubular section 202 to the support.

[0057] Diametrically opposed, radially extending vertical plate mounting tabs 210 extend upwardly normal to the upper face of flange 201. The thickness of the tabs 210 is such that they are a close fit to the gap between the ears 60 or 160 of the tubing terminations 10 or 100, respectively, when the split clamp assemblies 50 or 150, respectively, are assembled around their anchor block assemblies 48 or 110. Symmetrically positioned mounting holes 211 normal to the diametrical plane of the mounting tabs 210 penetrate the tabs with a hole pattern the same as for the clamping bolt holes 61 or 161 of the split clamp halves 51 or 151, respectively. The spacing of the mounting holes 211 from the upper face of the flange 201 is such that the lower face of the clamp halves 51 or 151 of the tubing terminations 10 or 100, respectively, will bear on the upper face of the flange 201 at assembly of the clamp as indicated in FIGS. 13 and 15.

[0058] Referring to FIG. 14, the second mounting 300 can be seen to be structurally very similar to the first mounting 200 in most regards. Second mounting 300 consists of a short right circular tubular section 302 with an outwardly extending transverse right circular cylindrical annular flange 301 at its upper end. The flange 301 has a frustroconical transition section between its lower side and the exterior of the tubular section 302 to reduce stress concentrations between the two primary elements. The first mounting 300 has a right circular cylindrical coaxial through hole 303 extending vertically through its length. The diameter of the through hole 303 is selected to be such that the tubing bundle 90 can readily pass through the hole. If so desired, the diameter of the through hole 303 can be made sufficiently large that it can pass the assembled anchor block assemblage 48 of the first tubing termination embodiment 10 or the assembled anchor block assemblage 110 of the second tubing termination 100. However, the size of hole 303 should not be so large that at least a portion of the nearly semicylindrical transverse end of the split clamp assembly 50 or 150 would not bear on the flange 301 when the clamp assembly is concentrically positioned on the mounting 300. The mounting 300 typically would be attached to a supporting structure by the welding of the lower end of its tubular section 302 to the support.

[0059] Coplanar opposed, outwardly extending vertical plate mounting tabs 310 extend upwardly normal to the upper face of flange 301. The mounting tabs 310 are offset from the axis of symmetry of the second mounting 300 so that their coplanar faces closest to the axis of symmetry are spaced apart from that axis. The distance of separation from the axis is the same as that of the externally facing coplanar faces of the clamping ears 60 or 161 of the split clamps 50 or 150, respectively, from their axes of symmetry. Symmetrically positioned mounting holes 311 normal to the plane of the mounting tabs 310 penetrate the tabs with a hole pattern the same as for the clamping bolt holes 61 or 161 of the split clamp halves 51 or 151, respectively. The spacing of the mounting holes 311 from the upper face of the flange 301 is such that the lower face of the clamp halves 51 or 151 of the tubing terminations 10 or 100, respectively, will bear on the upper face of the flange 301 at assembly of the clamp as indicated in FIGS. 14 and 16.

[0060] FIG. 17 shows an alternative arrangement of the center anchor block 411 in which the center tube 91 of the tubing bundle 90 and the inlet/outlet end 495 for the center tube are butt welded to tubular extensions 420 protruding from the center anchor block. The center anchor block 411 which supports the center tube 91 of the tubing bundle 90 is a right circular cylindrical tube having a transverse upper face 412, a coaxial right circular through hole 413, an outer cylindrical surface 414, and a transverse lower face 415.

[0061] The diameter of the through hole 413 is a match to the inner diameter of the center tube 91. A large chamfer is positioned at the lower end of the anchor block 411 at the intersection of the outer cylindrical surface 414 and the lower transverse face 415. Centrally located in the middle of the outer cylindrical surface 414 is a right circular cylindrical coaxial reduced diameter central portion 416 of the center anchor block 411. The reduced diameter central portion 416 is connected to the upper and lower sections of the outer cylindrical surface 14 by upper frustroconical shoulder 417 and lower frustroconical shoulder 418, respectively. The frustroconical shoulder surfaces are inclined from the axis of the center anchor block 411 by similar angles in the range of 30.degree. to 60.degree..

[0062] Coaxial with the through bore 413 and extending outwardly from the upper 412 and lower 415 transverse faces are tubular connection extensions 420. Each tubular connection extension 420 has a through bore which matches the through bore 413 of the center anchor block 411, a heavy wall section joined to the transverse face of the anchor block by a fillet for stress relief, and a reduced wall section 421 which matches the wall thickness of the tube 91 or 495 to which it is joined by a butt weld 425. In this case, the inlet/outlet end 495 of the center tube is another tube. Similarly, the outer anchor blocks can be modified, as described for the center anchor block 411, with the same type of tubular connection extensions for the attachment by butt welding of the outer tubes 92 and outer tube inlet/outlet tubes.

Operation of the Invention

[0063] The operation of the tube bundle terminations of the present invention is primarily concerned with the assembly of the structures, since the apparatus is stationary and passive following assembly. The characteristic of the construction of the tube bundle 90 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 92 in the bundle 90 are laid into their helical pattern utilizing only bending, rather than torsion, while the center tube 91 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 92 is required to reestablish the desired compact bundle geometry at the end of the bundle 90.

[0064] The assembly of the tube bundle termination 10 proceeds as follows. The ends of the outer tubes 92 at the end of the bundle 90 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 96 or an inner tube inlet/outlet end 95, respectively. Following this, the inner tube inlet/outlet end 95 and each of the outer tube inlet/outlet ends 96 is slipped into the through bore 13 of center anchor block 11 or the through bore 42 of outer anchor block 30, as appropriate.

[0065] At this point, the anchor blocks 11 and 30 are reassembled by elastically bending the tubes 92 into the packed pattern of their assemblage 48 as shown in FIGS. 1, 6, and 7 or in FIGS. 13 and 14, where the assemblage can be seen more clearly. Following this, the split clamp assembly 50 is assembled around the assembled anchor block pattern by engaging the clamp halves 51 around the assemblage 48 of anchor blocks 11 and 30 and then tightening the nuts 65 on the studs 64 after insertion of the studs through the clamping bolt holes 61 in the clamping ears 60. At this point, match marks between each tube inlet/outlet end 95 or 96 and its corresponding anchor block can be made for both radial alignment and axial positioning. Alternatively, tack welds of the tube inlet/outlet ends 95 or 96 with their respective anchor blocks 11 or 30 can be made to hold the desired alignment therebetween. At this point, the clamp assembly 50 can be removed, the anchor blocks reseparated, and the circumferential fillet welds 19 and 44 made to rigidly affix the inlet/outlet ends 95 or 96 to their respective blocks 11 or 30. If tack welds are 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 19 or 44.

[0066] When the connecting fillet welds 19 and 44 are completed, the anchor blocks 11 and 30 can be recombined into the anchor block assemblage 48. Final assembly is completed by clamping the assembly 10 together using the split clamp assembly 50. The split clamp halves 51 tightly grip the anchor block assemblage 48 when the threaded studs 64 and their nuts 65 are tightened. After this assembly operation, the tube bundle termination 10 is fully rigidized and can resist axial loads in either direction of the tube bundle 90. When the axial load is tension in the tube bundle 90, the axial load is resisted by abutment of the frustroconical shoulder 17 of the center anchor block 11 on the comated frustroconical shoulders 34 of the outer anchor blocks 30 and the abutment of the frustroconical shoulders 39 of the outer anchor blocks 30 on the upper frustroconical shoulders 58 of the split clamp assembly 50.

[0067] Mounting of the tubing termination embodiments 10 and 100 by means of either of the mountings 200 or 300 may be understood by reference to FIGS. 13 through 16. By means of example, the use of the mountings is shown for the first tubing termination 10, but the same arrangements are used for the second tubing termination 100.

[0068] Referring to FIGS. 13 and 15, for the first mounting 200 the tube bundle 90 is positioned in the hole 203 so that the anchor block assembly 48 of the tubing termination 100 is on the flange side of the mounting. The split clamp assembly 50 is separated at this point. The clamp bolt holes 61 of the clamp halves 51 of the split clamp 50 are then aligned with the mounting holes 211 of the mounting tabs 210 of the mounting 200. The clamp halves 51 are on opposed sides of the mounting tabs 210 at this point, and the anchor block assembly 48 is also aligned to be concentric with the mounting 200 and in axial alignment with the clamp halves. At this point, the studs 64 are engaged through both the mounting holes 211 of the mounting tabs 210 and the clamping bolt holes 61. The clamp halves 51 are then pulled together by means of tightening the nuts 65 on the studs 64 so that the clamp halves rigidly clamp the anchor block assembly 48 and also closely engage the mounting tabs 210. When the assembly is complete, the lower transverse side of the split clamp assembly 50 abuts the top surface of the flange 201 of the mounting 200.

[0069] For the second mounting 300, again illustrated with the first tubing termination 10 in FIGS. 14 and 16, the tube bundle 90 is positioned in the hole 303 so that the anchor block assembly 48 of the tubing termination 100 is on the flange side of the mounting. The nuts 65 are removed and the studs 64 are at least partially withdrawn. The clamp bolt holes 61 of the clamp halves 51 of the split clamp 50 are then aligned with the mounting holes 311 of the mounting tabs 310 of the mounting 300. The clamp halves 51 are on the same side of the mounting tabs 310 as the axis of symmetry of the mounting 300 at this point, and the anchor block assembly 48 is also aligned to be concentric with the mounting 300 and in axial alignment with the clamp halves. The studs 64 then are engaged through both the mounting holes 311 of the mounting tabs 310 and the clamping bolt holes 61. The clamp halves 51 are then pulled together by means of tightening the nuts 65 on the studs 64 so that the clamp halves rigidly clamp the anchor block assembly 48 and also closely engage the mounting tabs 310. When the assembly is complete, the lower transverse side of the split clamp assembly 50 abuts the top surface of the flange 301 of the mounting 300.

[0070] Generally, it is desirable to mount the completed tubing termination 10 so that it is adequately anchored and hence able to resist axial loadings. Various types of mountings are suitable for this purpose, including fixed mountings such as 200 or 300 or ball jointed, flex jointed, or trunnion mountings. Herein, for sake of example, the attachment of the split clamp assembly 50 of the tubing termination 10 to a fixed mounting such as either the first mounting 200 or the second mounting 300, as shown respectively in FIGS. 15 and 16, completes the mounting of the assembly.

[0071] Resistance by the tubing termination 10 to axial compressive loads in the tube bundle 90 is then provided by abutment of the frustroconical shoulder 18 of the center anchor block 11 on the comated frustroconical shoulders 35 of the outer anchor blocks 30 and the abutment of the frustroconical shoulders 40 of the outer anchor blocks 30 on the lower frustroconical shoulders 59 of the split clamp assembly 50. For the case of tension loadings in the tubing bundle 90, the lower transverse side of the split clamp 50 will bear directly on respectively the upper transverse surface 201 or 301 of the first 200 or second 300 mounting. In the case of compression loadings in the tubing bundle 90, transverse shear from the split clamp halves 51 of the clamp assembly 50 is transferred from the clamping bolt holes 61 to the clamp studs 64 and thence respectively to the mounting holes 211 or 311 of the support tabs 210 of first mounting 200 or tabs 310 of second mounting 300.

[0072] The assembly and operation of the second embodiment of the tube termination 100 is very similar to that of the first embodiment tube termination 10. Slightly more care is required in maintaining proper alignment between the anchor blocks and the inlet/outlet tube ends during fitup and welding in order to nest the outer anchor blocks 130 within the flanges 112 and 118 of the center anchor block 111. The difference between the two embodiments is related to the means for resisting axial loads produced by axial loadings induced by the tube bundle 90. The tube termination 100 is assembled in a manner identical to that used for the termination 10. Thus, the alignment marking and the welding follow the same procedures as used for the first embodiment.

[0073] For this embodiment 100 when axial tension is induced in the tube bundle 90, the upper flange 112 of the center anchor block 111 abuts the upper transverse faces of the upper flanges 131 of the outer anchor blocks 130, while the upper flanges 131 of the anchor blocks 130 abut the upper side of the split clamp assembly 150. For thrust loads from the tube bundle 90, the lower flange 118 of the center anchor block 111 abuts the lower transverse faces of the flanges 136 of the outer anchor blocks 130, while the lower flanges 136 of the anchor blocks 130 abut the lower side of the split clamp assembly 150.

[0074] The operation of the alternative center anchor block 411 shown in FIG. 17 is substantially identical to that of the anchor block 11 of the first embodiment of the tubing termination 10. The only difference for anchor block 411 is in the use of butt welds 425 without a through tube 95 for the connections and the provision of strain relief by means of tapered wall sections and fillets for the tubular extensions 420. Moving the butt welds 425 away from the transverse end faces 412 and 415 also improves the access for the welder.

Advantages of the Invention

[0075] A major advantage of the present invention is the ability to physically separate the anchor blocks of the tube bundle terminations by sufficient space that the necessary connecting welds 19 and 44 respectively between the center anchor block 11 (or 111) and the outer anchor blocks 30 (or 130) and the respective inlet/outlet tube ends 95 and 96 of tubes 91 and 92 of the helical tube bundle 90 can be readily made. This ability directly results from the segmentation of the anchor block assemblage 48 (or 110) to which the tubes are joined by welding into a set of discrete, separable, but comatable anchor blocks wherein one block is provided for each tube in the tube bundle.

[0076] Because of this ability to separate the anchor blocks, the center-to-center spacing of the tubes in the assembled tubing 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.

[0077] The present invention provides a more flexible means for terminating helical tubing bundles than the conventional welding or potting of the tubes into a socket with a plastic. Should there be a problem with one tube, the termination assembly can be readily disassembled, repaired, and reassembled. This flexibility greatly improves the ability to maintain the termination.

[0078] The tubing termination 10 can be assembled with particular ease, so that it offers the quickest assembly of the set of terminations of the present invention. This ease of assembly is due to the interaction of the frustroconical shoulders of the center tube anchor 11, the outer tube anchors 30, and of the split clamp assembly 50. The wedging interaction of the abutting frustroconical shoulders when the anchor block assemblage 48 is circumferentially pulled together causes good relative axial alignment of anchor blocks of the tubing termination 10 with the split clamp 50. The abutment of adjacent frustroconical shoulders in the assembled tubing termination 10 offers very high resistance to axial loads imposed by the tubing bundle 90. Likewise, the positioning of the tubing termination 10 on a mounting such as the first 200 or the second mounting 300 permits the assembled tubing termination to support high axial loads, particularly in the case of tube bundle tension.

[0079] The second tubing termination embodiment 100 offers substantially the same advantages as the first embodiment 10 such as ease of assembly and reduction in size and cost of the termination. The tubing termination 100 also is relatively easy to assembly if reasonable care is taken both to make accurate alignment marks for the inlet/outlet ends of the tubes and the anchor blocks and also to ensure that the welds between the inlet/outlet ends and the anchor blocks maintain that alignment. In such an event, the outer anchor blocks 130 readily may be engaged between the upper 112 and lower 118 flanges of the center anchor block 111 , while the upper 131 and lower flanges 136 of the outer anchor blocks 130 engage the upper and lower transverse faces of the split clamp assembly 150. This second embodiment of the tubing termination 100 is also highly resistant to axial loads from the helical tubing bundle 90 when the termination is fixed to a mounting structure like the first 200 or the second 300 mounting.

[0080] Referring to FIG. 17, the outer anchor blocks can likewise be modified similarly to the center anchor block 411 with the same type of tubular connection extensions for the attachment by butt welding of the outer tubes 92 and outer tube inlet/outlet tubes. Although construction of the anchor blocks is more difficult, use of this approach permits overly high bending stress concentrations from occurring in the tubes adjacent to the transverse end faces of the anchor blocks.

[0081] 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. In some cases when the helical tubing in the bundle 90 has thick walls, it may be possible to directly weld the tubes to the anchor blocks without using special inlet/outlet tube ends. 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. The split clamp halves can be made without having the upper and lower reinforcing flanges. Different types of mountings than those shown herein may be used without departing from the spirit of the invention. The frustroconical shoulders for the first embodiment may extend from the central cylindrical sections to the transverse end faces without changing the basic functionality of the present invention. Likewise, the choice is arbitrary of which side should be male with the other side female for a comating pair of surfaces for a center anchor block to outer anchor block mate or for an outer anchor block to split clamp assembly mate. These and other variations all can be made without changing the spirit of the invention.

Claims

1. A subsea termination device for a helical tubing bundle comprising: a) a center anchor block attached to a center tube of a tubing bundle; b) a plurality of outer anchor blocks surrounding the inner anchor block, each outer anchor block attached to an outer tube of the tubing bundle, wherein each outer anchor block has an interior surface abutting an outer surface of the center anchor block and an exterior surface; and c) a selectably removable clamp, wherein the clamp surrounds and engages the exterior surface of the outer anchor blocks.

2. The subsea termination device of claim 1, wherein the interior surface of the outer anchor blocks is comatable with the outer surface of the center anchor block.

3. The subsea termination device of claim 1, wherein the outer anchor blocks constitute a segmented ring.

4. The subsea termination device of claim 1, wherein the center anchor block is attached to the center tube by welding.

5. The subsea termination device of claim 1, wherein the outer anchor blocks are attached to the outer tubes by welding.

6. The subsea termination device of claim 1, wherein the clamp is a split clamp assembly having a first clamp half and a second clamp half cojoined by threaded fasteners.

7. The subsea termination device of claim 6, wherein a flange on each outer anchor block engages the first or second clamp half.

8. The subsea termination device of claim 1, wherein the center anchor block and the outer anchor blocks have comating frustoconical surfaces.

9. The subsea termination device of claim 1, wherein each outer anchor block is retained within two opposed transverse flanges of the center anchor block.

10. The subsea termination device of claim 1, wherein each outer anchor block comprises: a transverse flange, a right circular partial cylindrical inner face, a symmetrically positioned right circular through hole, and a right circular partial cylindrical outer face.

11. The subsea termination device of claim 10, wherein a radius of the inner face of the outer anchor block is substantially similar to a radius of an outer cylindrical surface of the center anchor block.

12. The subsea termination device of claim 1, wherein an upper transverse face of the outer anchor block abuts a flange of the center anchor block.

13. The subsea termination device of claim 1, wherein the center anchor block and the outer anchor blocks have a radially outwardly extending transverse flange and wherein the flange of the center anchor block abuts a side of each of the outer anchor blocks and the flange of the outer anchor blocks engages the clamp.

14. The subsea termination device of claim 1, wherein the clamp is mounted on a mounting structure comprising a tubular section having an outwardly extending transverse flange.

15. The subsea termination device of claim 14, wherein the transverse flange has a frustroconical transition section where the flange joins the tubular section of the mounting structure.

16. The subsea termination device of claim 14, wherein the mounting structure has a through hole with a diameter sufficiently large for the tubing bundle to pass through the through hole.

17. The termination device of claim 1, wherein a) the outer surface of the center anchor block is frustroconical with a taper in a first direction; b) the interior surface of each outer anchor block is frustroconical with a taper in the same direction as the frustroconical outer surface of the center anchor block and comateable with the outer surface of the center anchor block; c) the exterior surface of each outer anchor block is frustroconical with a taper in the same direction as the frustroconical outer surface of the center anchor block; and d) an inner face of the clamp is frustroconical with a taper in the same direction as the frustroconical outer surface of the center anchor block and comateable with the exterior surface of the outer anchor blocks, thereby permitting the inner and outer anchor blocks to resist axial movement.

18. A termination device comprising: a) an anchor block assemblage having a center anchor block attached to a center tube of a tubing bundle, a plurality of outer anchor blocks surrounding the center anchor block wherein each outer anchor block has an interior surface comateable with an outer surface of the center anchor block; b) a ring clamp engageable around the anchor block assemblage to thereby rigidize the anchor block assemblage; and c) a retaining means for restraining the axial motion of the center and outer anchor blocks.

19. The termination device of claim 18, wherein the retaining means includes a pair of opposed flanges on the inner and the outer anchor blocks.

20. The termination device of claim 18, wherein the retaining means includes: a) a pair of opposed center anchor block flanges, one flange extending radially outward from a first end of the center anchor block and a second flange extending radially outward from a second end of the center anchor block; b) a pair of opposed outer anchor block flanges, one flange extending radially outward from a first end of each outer anchor block and a second flange extending radially outward from a second end of each outer anchor block; c) the flange at the first end of the center anchor block abuts the first end of each of the outer anchor blocks; d) the flanges at the first end of the outer anchor blocks abut a one end of a first side of the ring clamp; e) the flange at the second end of the center anchor block abuts the second end of each of the outer anchor blocks; and f) the flanges at the second end of the outer anchor blocks abut a second end of the first side of the ring clamp.

21. The termination device of claim 18, wherein the outer anchor blocks constitute a segmented ring.

22. The subsea termination device of claim 18, wherein the retaining means includes the center anchor block and the outer anchor blocks have comating frustoconical surfaces.

23. The termination device of claim 18, wherein the retaining means includes a) a first taper on the outer surface of the center anchor; b) a second taper on the interior surface of each outer anchor block, wherein the first and second tapers are comateable; c) a third taper on the exterior surface of each outer anchor block; and d) a fourth taper on the exterior surface of the outer anchor blocks, wherein the third and fourth tapers are comateable.

24. The subsea termination device of claim 18, wherein the clamp is mounted on a mounting structure comprising a tubular section having an outwardly extending transverse flange.