WO1997017567A1 - Coating of pipe joints - Google Patents
Coating of pipe joints Download PDFInfo
- Publication number
- WO1997017567A1 WO1997017567A1 PCT/GB1996/002657 GB9602657W WO9717567A1 WO 1997017567 A1 WO1997017567 A1 WO 1997017567A1 GB 9602657 W GB9602657 W GB 9602657W WO 9717567 A1 WO9717567 A1 WO 9717567A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- shell
- coating
- pipe
- joint
- pipes
- Prior art date
Links
- 238000000576 coating method Methods 0.000 title claims abstract description 76
- 239000011248 coating agent Substances 0.000 title claims abstract description 72
- 238000000034 method Methods 0.000 claims abstract description 37
- 239000000463 material Substances 0.000 claims abstract description 29
- 239000011800 void material Substances 0.000 claims abstract description 4
- 239000011257 shell material Substances 0.000 claims description 120
- 238000010438 heat treatment Methods 0.000 claims description 24
- 239000004743 Polypropylene Substances 0.000 claims description 20
- -1 polypropylene Polymers 0.000 claims description 20
- 229920001155 polypropylene Polymers 0.000 claims description 20
- 239000000835 fiber Substances 0.000 claims description 9
- 239000004744 fabric Substances 0.000 claims description 6
- 229920000642 polymer Polymers 0.000 claims description 6
- 239000002131 composite material Substances 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 4
- 238000002844 melting Methods 0.000 claims description 3
- 230000008018 melting Effects 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 3
- 238000004804 winding Methods 0.000 claims description 3
- 238000000926 separation method Methods 0.000 claims description 2
- 239000002184 metal Substances 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 7
- 230000004927 fusion Effects 0.000 description 6
- 238000002347 injection Methods 0.000 description 5
- 239000007924 injection Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000003466 welding Methods 0.000 description 4
- 238000001746 injection moulding Methods 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 230000001483 mobilizing effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000009993 protective function Effects 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 238000012549 training Methods 0.000 description 1
- 230000007306 turnover Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L59/00—Thermal insulation in general
- F16L59/14—Arrangements for the insulation of pipes or pipe systems
- F16L59/16—Arrangements specially adapted to local requirements at flanges, junctions, valves or the like
- F16L59/18—Arrangements specially adapted to local requirements at flanges, junctions, valves or the like adapted for joints
- F16L59/20—Arrangements specially adapted to local requirements at flanges, junctions, valves or the like adapted for joints for non-disconnectable joints
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L58/00—Protection of pipes or pipe fittings against corrosion or incrustation
- F16L58/18—Protection of pipes or pipe fittings against corrosion or incrustation specially adapted for pipe fittings
- F16L58/181—Protection of pipes or pipe fittings against corrosion or incrustation specially adapted for pipe fittings for non-disconnectable pipe joints
Definitions
- This invention relates to procedures and arrangements for coating of pipe joints, and relates more particularly but not exclusively to procedures and arrangements for forming polypropylene coatings around bare-metal joints in polypropylene-coated pipes.
- Polypropylene is a material which has recently found its place in the pipeline coating market.
- the new coating offers many advantages over those previously used, namely, superior insulation properties, resistance to fatigue induced by external pressure/temperature, and excellent abrasion resistance.
- the present invention provides procedures and arrangements which obviate or mitigate the above disadvantages.
- a method for coating a bare joint between two pipes otherwise provided with a pipe- coating comprising the steps of; providing a shell dimensioned to shroud the joint, the shell formed of a shell material which is compatible with the pipe-coating material of the pipe-coating; fitting the shell around the joint in contact with the pipe-coating on either side of the joint; and fusing selected parts of the shell to the pipe-coating provided on the pipes.
- the shell may be principally or entirely composed of a material which is selected to be csemically substantially identical to the material of the pipe- coating and which may also have the same physical form.
- the shell and the pipe-coating may both be principally or entirely composed of polypropylene.
- the shell may be constituted by two or more shell components each formed as a length of arcuate material, the shell components collectively forming a substantially cylindrical shroud for the joint.
- Fusing of selected parts of the shell to the pipe- coating may be undertaken by locally melting mutually contacting parts of the shell and of the pipe-coating.
- the shell is constituted by a plurality of shell components
- these components are preferably mutually fused along lines of mutual contact to form a unitary shroud, such mutual fusing of shell components preferably being carried out contemporaneously or simultaneously with fusing of the shell to the pipe- coating.
- Fusing is preferably carried out by highly localised heating.
- a filling material may be injected between the shell and the underlying pipe, preferably such as substantially to fill the void initially existing between the joint and the shell.
- apparatus for coating of pipe joints comprising; a shell dimensioned to shroud the joint, the shell being formed of a shell material which is compatible with the pipe-coating material of the pipe-coating, the shell being constructed or adapted to fit around the joint in contact with the pipe-coating on either side of the joint; and further comprising fusing means for fusing selected parts of the shell to the pipe- coating provided on the pipes.
- the shell may initially be in the form of two or more shell components each formed as a length of arcuate material, the shell components collectively forming a substantially cylindrical shroud for the joint.
- the shell is preferably initially in the form of two semi- cylindrical lengths.
- the inside diameter of the shell may be substantially equal to the outside diameter of the pipe-coating provided on the pipes on either side of the bare joint, and the length of the shell is preferably greater than the separation of material- coated portions of the pipe on either side of the bare joint such that the shell is ultimately lap-jointed to the pipe-coating.
- the shell may be principally or entirely composed of a material which is csemically identical to the material of the pipe-coating and which may also have the same physical form.
- the shell may be principally or entirely composed of polypropylene.
- the fusing means preferably comprises ohmic heating resistors located adjacent to or in contact with the selected parts of the shell that are to be fused to the pipe-coating.
- the ohmic heating resistors may be in the form of wire or tape located on or set into the parts of the shell to be fused to the pipe-coating, for example on the bore of the shell at longitudinally opposite ends thereof and (in the context of the plural-component shell) along the abutting longitudinal edges of the shell components.
- the shell may be provided with at least one fill hole and at least one vent hole whereby a filling material may be injected between the shell and the underlying pipe after fitting of the shell around the joint.
- a method of forming a sleeve comprising the steps of; winding a composite of polymeric fibre and initially molten polymer around a mandrel to form a mass of polymer; cooling the mass to form a solid shell; and providing local heating means on or adjacent to those parts of the shell which will subsequently contact the pipe-coating provided on the pipes.
- the polymeric fibre may be a polypropylene cloth which may be woven.
- the fibre may be coated with an extruded sheet or film of molten polypropylene.
- Strands of fibre may be arranged to extend from the inner face of the shell components to provide a key for material subsequently injected under the shell.
- the formed shell may be longitudinally divided into two or more shell components, and the local heating means extended to longitudinal edges of these components.
- Fig. 1 is a longitudinal elevation of a bare-metal joint between polypropylene-coated pipes
- Fig. 2 is a perspective view of the joint of Fig. 1, in the process of being shrouded by two shell components
- Fig. 3 is a perspective view of the shell components of Fig. 2 with their integral ohmic heating elements
- Fig. 4 is a perspective view of the layout of the heating elements of Fig. 3.
- this shows a welded joint 10 formed between and mutually joining two metal pipes 12 and 14 which may, for example, form part of a land pipeline or a submarine pipeline.
- the pipes 12 and 14 present bare metal in the immediate vicinity of the joint 10, but are otherwise respectively coated with layers 16 and 18 of polypropylene for the purposes of thermal insulation and corrosion protection.
- Welding of the joint 10 requires that the polymeric coating be removed from the pipes 12 and 14 in the immediate vicinity, but the protective function of the coating requires the subsequent restoration of an integral coating over the joint 10.
- Fig. 2 shows a preliminary stage in restoration of the coating around the joint 10, comprising the steps of providing two matching semi-cylindrical polypropylene shell halves 20 and 22, locating the shell halves on either side of the joint 10, and subsequently clamping the shell halves 20 and 22 tightly together by suitable clamps (not shown) .
- the shell formed by the shell halves 20 and 22 is dimensioned in terms of its bore (internal diameter) and overall length to be a tight overlapping fit on the coatings 16 and 18 on either side of the joint 10, with the longitudinal edges of the shell halves 20 and 22 in firm mutual contact.
- Fig. 3 shows ohmic heating elements 24 and 26 pre- fitted in the shell halves 20 and 22 respectively, to lie along one longitudinal edge of each shell half, and around the semi-circumference of the bore at each end of each shell half.
- the heating elements 24 and 26 extend along each shell half 20 and 22 on a "once- through" basis, and beyond each half shell at both ends as pigtails or flying leads for subsequent temporary connection to a power supply, as detailed below.
- the layout of the heating elements 24 and 26 is depicted in Fig. 4.
- the heating elements 24 and 26 may each comprise a single strand of a suitable ohmic alloy (eg a nickel alloy) or (as schematically depicted in Fig. 3) as braided ribbons containing multiple strands of alloy wire.
- a suitable ohmic alloy eg a nickel alloy
- Fig. 3 braided ribbons containing multiple strands of alloy wire.
- the shell halves 20 and 22 are shown slightly separated for clarity, but they will in fact be tightly clamped together at the time that the heating elements 24 and 26 are connected to a suitable source of electric power. Electrical energisation of the heating elements 24 and 26 (either simultaneously or sequentially, and at a suitable power level) will cause them to heat up by ohmic conversion of electric power directly into heat, thereby causing localised melting of the mutually contacting portions of the shell halves 20 and 22, and of the underlying pipe coatings 16 and 18. After a suitable interval, power to the heating elements is switched off, and the elements are allowed to cool to ambient temperature. The polypropylene in the localised volumes around the heating elements resolidifies, thereby fusing together the contacting masses and forming a unitary solidified sleeve around the joint 10.
- the interior of the fused-in-place sleeve will be hollow around the joint 10. This hollow may optionally be filled with a suitable material, placed in the hollow by injection.
- Each of the half shells 20 and 22 may have a respective hole 28, 30 drilled or otherwise formed in it, either subsequent to fusing or preformed with the original shell. The lower one of the holes 28, 30 will serve for injection of the filling material while the upper one of these holes will serve as a vent during injection.
- the proposed method of creating a spiral of woven polypropylene cloth coated with a layer of molten polypropylene, wrapped round a mandrel to form a solid tube overcomes the problems.
- the cloth is pre-woven in bulk and is coated with extruded molten polypropylene sheet or film. It is then wrapped round a mandrel which may be of any size.
- the only tooling required to alter the dimensions is a relatively inexpensive mandrel which may or may not have special features included on its surface.
- the shell segment is very stable and does not distort significantly during subsequent processing.
- a slot(s) or cut(s) may be formed in the inside of the segment(s), leaving a thin section parallel to the axis of the segment.
- the cloth in this thinned section forms a hinge, allowing the segment to open along this axis. This would allow a segment of greater than a half section to be fitted over the pipe.
- the slot could subsequently be filled with a plastic material to restore the strength of the segment.
- the present invention utilises pre-formed modular segments (as detailed above) where the unique method of their manufacture allows a variable "shell” thickness to be produced if required without the need for moulds.
- the segments are pre-wired along each jointing area face using electrical welding elements in the form of tapes.
- the "shells” are fitted around the "field joint” area and compressed and held in position using a special clamping device.
- the tape ends are clamped in the sequence as in the diagrams accompanying this text, ie Figs. 3 and 4, via a simple electronic control unit which varies electrical current to the welding tapes.
- the unit houses a series of control components such as transformers, variable input/output regulators, a timer device and an automatic cut-out.
- the fusion/timer sequence is set and the unit is then energised creating a "welded field joint" encapsulation.
- the resultant polypropylene joint can be utilised to act as a stand-alone coating or as a carrier void for a variety of csemical infill composite components, which can be facilitated by the addition at manufacture of injection and vent ports in the segments (see Fig. 3).
- the installation sequence is as follows:-
- a Clean bare metal of all contaminants, oil etc. B Prepare ends of pipe at field joint area by simple scraping to remove oxidised layer. C Apply anti-corrosion coat to bare metal up to the ends of the metal/coating interface. D Apply segments, position and clamp in place. E Fit welding/control unit leads to fusion tapes, set the weld/fusion time (this can operate automatically), and energise the unit. The joint is thereby fusion bonded to the mill coat and the segments fuse together also.
- the inner surfaces of the shell may be pre-treated to provide a key or tie coat for csemical infill products placed via injection or by other means. They may also have a pre- assembled bonded insulation layer added at segment manufacture.
- the fusion-based joint-coating system described above offers great benefits to the pipelaying market by way of its simplicity, economy and its practicality especially where laybarge or reelship installation of offshore pipelines is required.
- the capital plant costs are low and the cost of maintenance is likewise.
- Minimal training is needed for operatives and repeatability of joint quality is controlled by the fusion unit.
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU73210/96A AU7321096A (en) | 1995-11-04 | 1996-11-01 | Coating of pipe joints |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB9522646.0A GB9522646D0 (en) | 1995-11-04 | 1995-11-04 | Coating of pipe joints |
GB9522646.0 | 1995-11-04 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997017567A1 true WO1997017567A1 (en) | 1997-05-15 |
Family
ID=10783409
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1996/002657 WO1997017567A1 (en) | 1995-11-04 | 1996-11-01 | Coating of pipe joints |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU7321096A (en) |
GB (1) | GB9522646D0 (en) |
WO (1) | WO1997017567A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE10006980A1 (en) * | 2000-02-16 | 2001-09-06 | Willoc Holding B V | Coating process for solid parts connected by movable zones involves fixedly placing coating on solid elements whilst placing coating loose in area of movable zones |
GB2507572A (en) * | 2012-11-05 | 2014-05-07 | Lee Cothill Arran | Pipe joint insulation |
EP4253716A3 (en) * | 2017-04-12 | 2023-12-06 | Weatherford Technology Holdings, LLC | Shroud assembly |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4096017A (en) * | 1977-02-18 | 1978-06-20 | H. C. Price Co. | Method and article for forming field joints on pipe coated with thermoplastic material |
EP0030776A2 (en) * | 1979-12-18 | 1981-06-24 | i.c. Möller a/s | A method of providing a mantle tube connection across a joint between heat insulated pipes |
FR2710723A1 (en) * | 1993-09-29 | 1995-04-07 | Gts Isopipe | Method for connecting a pipe insulating jacket and connecting shell for employing this method |
-
1995
- 1995-11-04 GB GBGB9522646.0A patent/GB9522646D0/en active Pending
-
1996
- 1996-11-01 AU AU73210/96A patent/AU7321096A/en not_active Abandoned
- 1996-11-01 WO PCT/GB1996/002657 patent/WO1997017567A1/en active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4096017A (en) * | 1977-02-18 | 1978-06-20 | H. C. Price Co. | Method and article for forming field joints on pipe coated with thermoplastic material |
EP0030776A2 (en) * | 1979-12-18 | 1981-06-24 | i.c. Möller a/s | A method of providing a mantle tube connection across a joint between heat insulated pipes |
FR2710723A1 (en) * | 1993-09-29 | 1995-04-07 | Gts Isopipe | Method for connecting a pipe insulating jacket and connecting shell for employing this method |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE10006980A1 (en) * | 2000-02-16 | 2001-09-06 | Willoc Holding B V | Coating process for solid parts connected by movable zones involves fixedly placing coating on solid elements whilst placing coating loose in area of movable zones |
DE10006980C2 (en) * | 2000-02-16 | 2003-06-26 | Willoc Holding B V | Process for coating hollow elements |
GB2507572A (en) * | 2012-11-05 | 2014-05-07 | Lee Cothill Arran | Pipe joint insulation |
EP4253716A3 (en) * | 2017-04-12 | 2023-12-06 | Weatherford Technology Holdings, LLC | Shroud assembly |
EP3610126B1 (en) * | 2017-04-12 | 2025-03-12 | Weatherford Technology Holdings, LLC | Shroud assembly |
Also Published As
Publication number | Publication date |
---|---|
AU7321096A (en) | 1997-05-29 |
GB9522646D0 (en) | 1996-01-03 |
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