Termination for segmented steel tube bundle

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

BACKGROUND OF THE INVENTION

1. Field Of The Invention

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.

2. Description of the Related Art

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.

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.

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

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.

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.

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.

Another aspect of the present invention is

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

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:

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.

FIG. 2 shows the tubing termination of FIG. 1 from its second side where the tubing bundle is attached.

FIG. 3 is an oblique exploded view of the tubing termination of FIGS. 1 and 2.

FIG. 4 is an axial plan view of the tubing termination of FIGS. 1, 2, and 3, taken from the first side.

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.

FIG. 6 shows an oblique view of the tubing termination of FIG. 1 mounted on a bend limiter device.

FIG. 7 is a longitudinal section through the axis of the tubing termination and bend limiter of FIG. 6.

FIG. 8 is an axial view from the first side of a second embodiment of the tubing termination of the present invention.

FIG. 9 shows an oblique exploded view of the tubing termination of FIG. 8.

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.

FIG. 11 is a plan view of a third embodiment of the tubing bundle termination of the present invention.

FIG. 12 is a vertical sectional view taken along line 12-12 of the tubing bundle termination shown in FIG. 11.

FIG. 13 is an oblique view of the tubing bundle termination shown in FIGS. 11 and 12.

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.

FIG. 15 is an oblique view of a typical helical tubing bundle consisting of seven equisized tubes.

FIG. 16 is an oblique view of a fourth embodiment of the tubing bundle termination of the present invention.

FIG. 17 is an oblique exploded view of the tubing bundle termination of FIG. 16.

FIG. 18 is a plan view taken from the inlet/outlet side of the tubing bundle termination of FIGS. 16 and 17.

FIG. 19 is a longitudinal sectional view taken along line 19-19 of FIG. 18.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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, each outer anchor block attached to an outer tube of the tubing bundle, wherein an interior surface of each outer anchor block is comateable with an outer surface of the center anchor block to form an anchor block assemblage; and c) a ring clamp engageable around the anchor block assemblage to thereby rigidize the anchor block assemblage.

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

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

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

5. The subsea termination device of claim 4, wherein a flange on each outer anchor block is mounted on the first or second clamp half.

6. 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.

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

8. The subsea termination device of claim 5, wherein the radius of the inner face of the outer anchor block has a substantially similar radius as an outer cylindrical surface of the center anchor block.

9. 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.

10. The subsea termination device of claim 1, further comprising a bend limiting assembly.

11. The subsea termination device of claim 10, wherein the bend limiting assembly includes a lower socket, two mirror-image retainer halves, and a swivel head.

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

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

14. The subsea termination device of claim 1, wherein the center anchor block and the outer anchor blocks have a radially outwardly extending transverse flange, 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 ring clamp.

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

16. The termination device of claim 15, wherein the retaining means includes a pair of opposed flanges on the inner and the outer anchor blocks.

17. The termination device of claim 15, 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 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 side of the ring clamp; whereby the termination device permits the anchor block assemblage to resist axial motion in either direction.

18. The termination device of claim 15, wherein the outer anchor blocks constitute a segmented ring.

19. The termination device of claim 15, wherein a) the outer surface of rotation 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) an 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 ring 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 anchor block assemblage to resist axial movement in the said taper direction.

20. The termination device of claim 15, further comprising a bend limiting assembly.

21. The termination device of claim 20, wherein the bend limiting assembly consists of: a) a socket element having a frustrospherical internal cavity; b) a ball element having: i) a cylindrical neck supporting a coaxial frustrospherical external upset comateable with the internal cavity of said socket element; ii) a coaxial through bore; and iii) a transverse mounting surface with anchorages for the attachment of the ring clamp, whereby the ball element is rotatable in the socket element within limits imposed by the impingement of the cylindrical neck against the socket element.