MACHINE FOR SPRAYING A SECTION OF PIPELINE

Abstract

A machine and a process for spraying a section of pipeline with air and water. The machine comprises an enclosure configured to surround a section of pipeline; a frame rotatable about a section of pipeline in the enclosure; rotating means operable to rotate the frame; a water delivery arrangement mounted on the frame and rotatable therewith to spray water around a section of pipeline in the enclosure; and an air delivery arrangement mounted on the frame and rotatable therewith to spray air around a section of pipeline in the enclosure. The machine may be used quenching or jet washing a section of pipeline. Optionally, the machine may comprise a heater arrangement mounted on the frame and rotatable therewith to help dry a section of pipeline after it has been jet washed.

Claims

1. A machine for spraying a section of pipeline, the machine comprising: an enclosure configured to surround a section of pipeline; a frame rotatable about a section of pipeline in the enclosure; rotating means operable to rotate the frame; a water delivery arrangement mounted on the frame and rotatable therewith to spray water around a section of pipeline in the enclosure; and an air delivery arrangement mounted on the frame and rotatable therewith to spray air around a section of pipeline in the enclosure.

2. The machine of claim 1, wherein the air delivery arrangement is rotationally displaced about the axis of rotation of the frame from the water delivery arrangement.

3. The machine of claim 1, wherein the water delivery arrangement comprises a plurality of water delivery manifolds each water delivery manifold being mounted at substantially equiangular intervals about the axis.

4. The machine of claim 1, wherein the water delivery arrangement is capable of spraying water at between 50 and 150 Bar pressure, preferably at substantially 100 Bar pressure.

5. The machine of claim 1, wherein the water delivery arrangement is capable of spraying water at between 2 and 6 Bar pressure, preferably at substantially 4 Bar pressure.

6. The machine of claim 1, wherein the machine comprises a heater arrangement mounted on the frame and rotatable therewith to heat a section of pipeline in the enclosure, and preferably wherein the heater arrangement comprises an induction heater arrangement.

7. The machine of claim 6, wherein the heater arrangement comprises a plurality of heaters each heater being mounted at angular intervals about the axis.

8. The machine of claim 1, wherein the water delivery arrangement is fluidly coupled to a source of water cooled to below ten degrees Celsius.

9. The machine of claim 1, wherein the air delivery arrangement is capable of spraying air at between 4 and 8 Bar pressure, preferably at substantially 6 Bar pressure.

10. The machine of claim 1, wherein the air delivery arrangement comprises a plurality of air delivery manifolds each air delivery manifold being mounted at substantially equiangular intervals about the axis.

11. The machine of claim 1, wherein the machine comprises a hopper for collecting matter from the enclosure.

12. A process for spraying a section of pipeline, the process comprising: providing a machine for spraying a section of pipeline, the machine having an enclosure, a rotatable frame, rotating means operable to rotate the frame and a water delivery arrangement and an air delivery arrangement mounted on the frame and rotatable therewith; disposing the frame about the section of pipeline; surrounding a section of pipeline to be sprayed with the enclosure; operating rotating means to rotate the frame; directing one of the air delivery arrangement to spray air around the section of pipeline or the water delivery arrangement to spray water around the section of pipeline; and directing the other of the air delivery arrangement to spray air around the section of pipeline or the water delivery arrangement to spray water around the section of pipeline.

13. The process of claim 12, wherein the process comprises: directing the air delivery arrangement to spray air around the section of pipeline for substantially one minute; directing the water delivery arrangement to spray water around the section of pipeline for substantially three minutes; and optionally directing the air delivery arrangement to spray air around the section of pipeline for up to one minute.

14. The process of claim 12, wherein the air delivery arrangement is directed to spray air at between 4 and 8 Bar pressure and the water delivery arrangement is directed to spray water at between 2 and 6 Bar pressure.

15. The process of claim 12, wherein the process comprises: directing the water delivery arrangement to spray water around the section of pipeline for substantially thirty seconds; directing the air delivery arrangement to spray air around the section of pipeline for substantially one minute; and optionally directing a heater arrangement mounted on the frame and rotatable therewith to heat the section of pipeline, preferably to a temperature of between 90 and 130 degrees Celsius.

16. The process of claim 15, wherein the water delivery arrangement is directed to spray water at between 50 and 150 Bar pressure and the air delivery arrangement is directed to spray air at between 4 and 8 Bar pressure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will now be explained, by way of example only, with reference to the accompanying drawings of which:

[0034] FIG. 1 shows a cross-sectional view of two joined pipe sections;

[0035] FIG. 2 shows a perspective view of a first embodiment or a second embodiment of a machine according to the present invention;

[0036] FIG. 3 shows a side elevation view of the machine of FIG. 2 and indicates the position of sections IV-IV and VI-VI;

[0037] FIG. 4 shows a cross-section view IV-IV of the first embodiment of the machine;

[0038] FIG. 5 shows a perspective view of a cylindrical frame of the first embodiment of the machine;

[0039] FIG. 6 shows a cross-section view VI-VI of the second embodiment of the machine;

[0040] FIG. 7 shows a perspective view of a cylindrical frame of the second embodiment of the machine;

[0041] FIG. 8 shows a side elevation view of an air delivery manifold;

[0042] FIG. 9 shows a side elevation view of a low pressure water delivery manifold;

[0043] FIG. 10 shows a side elevation view of water being sprayed from the low pressure water delivery manifold upon a field joint coating of a section of pipeline;

[0044] FIG. 11 shows a end view of water being sprayed from three low pressure water delivery manifolds upon a field joint coating of a section of pipeline;

[0045] FIG. 12 shows a side elevation view of a high pressure water delivery manifold;

[0046] FIG. 13 shows a side elevation view of an induction heater plate; and

[0047] FIG. 14 shows a schematic diagram of a water cooling circuit.

DETAILED DESCRIPTION OF THE INVENTION

[0048] As mentioned above, multiple hollow cylindrical steel pipe sections are welded together to construct a pipeline. The individual lengths of pipe sections are, prior to being welded into a pipeline, normally coated at a factory remote from where the pipeline is laid.

[0049] Referring to FIG. 1, there are shown two steel pipe sections 2, 4 joined together in end-to-end relation by a welded joint 6 to form what is a section of a pipeline that may extend over many kilometres. The pipe sections 2, 4 have the same central longitudinal axis A-A. Approximately, but not limited to, 150 mm to 250 mm of bare steel at the ends 8, 10 of the pipe sections 2, 4 enables welding of the welded joint 6. The ends 8, 10 of the pipe sections 2, 4 and the welded joint 6 are referred to as the field joint. The rest of the pipe sections 2, 4 are coated with a factory-applied coating 12, 14 of material, like, for example, polypropylene, polyethylene or polyurethane material. The cylindrical portions 16, 18 of the factory-applied coating 12, 14 are progressively cut back as conical chamfered portions 20, 22 in the approach to the bare steel ends 8, 10 of the pipe sections 2, 4. The location of where a field joint coating 24 would fill the gap between the two factory-applied coatings 12, 14 is shown in ghost lines.

[0050] Referring to FIGS. 2 and 3, there is shown a machine 100 for spraying a section of pipeline with water and air according to the present invention. The machine 100 comprises a generally cuboids-shaped enclosure 102. The enclosure 102 has in internal cavity through which may pass a sequence of pipe sections welded together at field joints to form a pipeline. The enclosure 102 has a pair of mutually aligned circular pipeline holes 104a, 104b, one through each opposite end of the body and coaxial with a longitudinal axis A-A through the centre of the machine 100. The pipeline holes 104a, 104b, are large enough to accommodate the passage of pipelines having various diameters of anywhere between 0.05 metres to 1.5 metres.

[0051] The enclosure 100 has a lockable hinged door 106a, 106b on each opposite side to provide an operator with access to inside the enclosure 102. Each door 106a, 106b has a respective window 108a, 108b providing an operator with visibility of inside the enclosure 102.

[0052] The bottom of the enclosure 102 is shaped as a hopper 110 to collect water, debris and any other matter falling towards the hopper 110, under gravity, and direct it towards a water extraction hose 112 at a lowest point of the hopper 110. The water extraction hose 112 delivers the water, either under gravity or by pumping, to a bath 300 which is outside the enclosure 102. A water delivery hose 114 delivers fresh water, or water recycled from the bath 300, to a water delivery port 116 located at the top of the enclosure 102, as is described in more detail below.

[0053] The machine 100 comprises a human/machine interface 118 to enable control of the machine 100 by an operator. The interface 118 presents an operator with a menu to start or stop the machine 100 and/or select a process. Other aspects of the process may be controlled automatically by the interface 118 once the operator has started the machine 100.

[0054] The enclosure 102 is supported on the ground by a base plate 120. The machine 100 comprises an electric motor 122 fixed to the enclosure 102. The electrical power supply to the motor 122 is controlled by the interface 118.

[0055] Referring to FIGS. 4 and 5, there is shown the inside of a first embodiment of the machine 100 which comprises a first frame 124 circumscribing a generally hollow cylindrical shape coaxial with the axis A-A of the pipeline holes 104a, 104b, and a pipeline in the enclosure 102. The first frame 124 is made of aluminium, stainless steel or another substantially rigid material. The first frame 124 is supported for rotation about the axis A-A by a pair of bearings 126a, 126b, one at each opposite axial end of the enclosure 102 adjacent a respective pipeline hole 104a, 104b. The motor 122 is coupled to the first frame 124 via a transmission (not shown) protected by a shroud 128. The transmission may be any mechanism capable of transmitting the motor's rotational output to rotation of the first frame, like, for example, an endless chain or belt or a drive shaft. The first frame 124 is rotatable by the motor 122 in both directions of double-headed arrow B through and arc of 120 degrees (+/−five degrees to help facilitate total spray coverage). The electrical power supply and operation of the motor 122 is controlled by the interface 118.

[0056] The first frame 124 comprises an arrangement of three low pressure (LP) water delivery manifolds 134a, 134b, 134c fixed to the perimeter of the first frame 124 at equiangular intervals of 120 degrees about the axis A-A. The LP water delivery manifolds 134a, 134b, 134c are arranged so that they may spray water over the whole circumference of a field joint coating 24 covering the ends 8, 10 of pipe sections 2, 4 (i.e. a field joint 6, 8, 10) in the enclosure 102, as is described in below. Water supply and operation of the LP water delivery manifolds 134a, 134b, 134c is controlled by the interface 118.

[0057] The first frame 124 comprises and arrangement of three air delivery manifolds 136a, 136b, 136c fixed to the perimeter of the first frame 124 at equiangular intervals of 120 degrees about the axis A-A. The air deliver manifold 136a is located approximately equidistantly between the LP water delivery manifolds 134a, 134b, the air deliver manifold 136b is located approximately equidistantly between the LP water delivery manifolds 134b, 134c, and air deliver manifold 136c is located approximately equidistantly between the LP water delivery manifolds 134c, 134a. The air deliver manifolds 136a, 136b, 136c are arranged so that they may blow a jet stream of compressed air in a line, or blade, spanning a field joint coating 24 in the enclosure 102, as is described in below. Air supply and operation of the air deliver manifolds 136a, 136band 136c is controlled by the interface 118.

[0058] Referring to FIGS. 6 and 7, there is shown a second embodiment of the machine 100 which comprises a second frame 138 circumscribing a generally cylindrical shape coaxial with the axis A-A of the pipeline holes 104a, 104b, and a pipeline in the enclosure 102. The second frame is made of aluminium, stainless steel or another substantially non-magnetic rigid material. The second frame 138 is supported for rotation about the axis A-A by the pair of bearings 126a, 126b. The motor 122 is coupled to the second frame 138 via a transmission (not shown) protected by the shroud 128. The transmission may be any mechanism capable of transmitting the motor's rotational output to rotation of the second frame, like, for example, an endless chain or belt or a drive shaft. The second frame 138 is rotatable by the motor 122 in both directions of double-headed arrow B through and arc of 180 degrees (+/−5 degrees to help facilitate total spray coverage).

[0059] The second frame 138 comprises an arrangement of three of high pressure (HP) water delivery manifolds 140a, 140b, 140c fixed to the perimeter of the second frame 138 at equiangular intervals of 120 degrees about the axis A-A. The HP water delivery manifolds 140a, 140b are arranged so that they may spray a water jet spanning a field joint 6, 8, 10 in the enclosure 102, as is described in below. Water supply and operation of the HP water delivery manifolds 140a, 140b, 140c is controlled by the interface 118.

[0060] The second frame 138 comprises an arrangement of three air delivery manifolds 136a, 136b, 136c fixed to the perimeter of the second frame 138 at equiangular intervals of 120 degrees about the axis A-A. The air deliver manifold 136a is located approximately forty degrees about the axis A-A in an anti-clockwise direction (when viewed in FIG. 6) from the HP water delivery manifold 140a. The air deliver manifold 136b is located approximately forty degrees about the axis A-A in an anti-clockwise direction from the HP water delivery manifold 140b. The air deliver manifold 136c is located approximately forty degrees about the axis A-A in an anti-clockwise direction from the HP water delivery manifold 140c. The air delivery manifolds 136a, 136b, 136c are arranged so that they may blow a jet of air in a line, or blade, spanning a field joint 6, 8, 10 in the enclosure 102, as is described in below. Air supply and operation of the air deliver manifolds 136a, 136b is controlled by the interface 118.

[0061] The second frame 138 comprises an arrangement of two of induction heater plates 142, 144 fixed to the perimeter of the second frame 138. The induction heater plates 142, 144 are an advantageous, though optional, feature which may be omitted from the second frame 138 to save space, weight or cost. The induction heater plate 142 is located approximately equidistantly between the HP water delivery manifold 140c and the air deliver manifold 136a. The induction heater plate 144 is located approximately equidistantly between the HP water delivery manifold 140b and the air deliver manifold 136c. Each induction heater plate 142, 144 has a partially cylindrical underside 142a, 144a facing a field joint 6, 8, 10 in the enclosure 102. The partially cylindrical undersides 142a, 144a are elongate in a direction parallel to the axis A-A so that they substantially span the whole length of the field joint 6, 8, 10 between the conical chamfers 20, 22 on the factory-applied coatings 12, 14. The longitudinal axes of the cylindrical undersides 142a, 144a are orientated parallel to the axis A-A and match, as far as possible, the cylindrical outer shape of the field joint 6, 8, 10. This helps the induction heater plates 142, 144 to direct and concentrate the induction heating effect towards the field joint 6, 8, 10. The electrical power supply and operation of the induction heater plates 142, 144 is controlled by the interface 118.

[0062] Referring to FIG. 8, there is shown the air delivery manifold 136a in more detail, it being understood that the other air delivery manifolds 136b, 136c have the same basic construction. The air delivery manifold 136a has a generally elongate profile when viewed from a side. The air delivery manifold 136a comprises a compressed air delivery tube 150 coupled to an air compressor (not shown) upstream of the air delivery tube 150. The air compressor is capable of compressing air to approximately 6 Bar and delivering a volumetric air flow of between approximately 80 litres/second (approximately 170 CFM) and approximately 21 litres/second (approximately 45 CFM) divided equally between the air delivery manifolds 136a, 136b, 136c. The air compressor is standard equipment controlled by the interface 118 which is not described in any more detail. The compressed air delivery tube 150 divides at a T-junction 152 to each of a pair of air blade compressed air inlets 154a, 154b. The air delivery manifold 136a comprises an air blade outlet 156 on the underside of an air blade frame 158. The air blade outlet 156 has an elongate slit which is arranged to face a field joint coating 24, or a field joint 6, 8, 10, in the enclosure 102 and which is arranged substantially parallel to the axis A-A. One air blade compressed air inlet 154a delivers compressed air to the air blade outlet 156 at about one quarter of the length of the air blade outlet 156 from one end. The other air blade compressed air inlet 154b delivers compressed air to the air blade outlet 156 at about one quarter of the length of the air blade outlet 156 from the other end. In use, the air blade outlet 156 emits an air spray plane 160 (i.e. an air blade) of compressed air fanning out from the air blade outlet 156 and approaching the field joint coating 24, or the field joint 6, 8, 10, in a direction substantially in line with the axis A-A. The air blade 160 has a truncated generally fan-shaped profile when viewed from one side, as is shown in particular by FIG. 8. The air delivery manifold 136a comprises a pair of adjuster plates 162, 164, one adjuster plate coupled to each end of the air blade frame 158. The adjuster plates 162, 164 are fixed to the second frame 138, part of which is shown in FIG. 8. The adjuster plates 162, 164 may be adjusted by an operator to vary a distance D1 between the air blade outlet 156 and the pipe sections 2, 4 (measured from the bare metal of the field joint 6, 8, 10) in the enclosure 102 and/or accommodate pipe sections 2, 4 or different diameters. The air blade outlet 156 remains substantially parallel to the axis A-A notwithstanding a change in distance D1.

[0063] Referring to FIGS. 9 to 11, there is shown the LP water delivery manifold 134a in more detail, it being understood that the other LP water delivery manifolds 134b, 134c have the same basic construction. The LP water delivery manifold 134a is a generally elongate cylinder when viewed from a side and which is arranged substantially parallel to the axis A-A. The LP water delivery manifold 134a comprises a low pressure water inlet 166 fluidly coupled to a low pressure (LP) water pump (not shown) up stream of the low pressure water inlet 166. The LP water pump is capable of pumping a volumetric water flow of approximately 40 litres/minute of water, chilled to around five degrees Celsius, to each of the LP water delivery manifolds 134a, 134b, 134c i.e. a total volumetric water flow of approximately 120 litres/minutes of water. The LP water pump is standard equipment controlled by the interface 118 which is not described in any more detail. The LP water delivery manifold 134a divides the water flow evenly between four low pressure water outlets 168a, 168b, 168c, 168d downstream for the LP water inlet 166. Each LP water outlet is a LP nozzle 168a, 168b, 168c, 168d that sprays water from the underside of the LP water delivery manifold 134a in the direction of a field joint coating 24 in the enclosure 102. In use, each LP nozzle 168a, 168b, 168c, 168d emits a conical spray 170 of water fanning outwardly so as the whole circumference of the field joint coating 24 is covered in water at the same time when viewed from one side, as is shown in particular by FIG. 10, and when viewed in the direction of the axis A-A, as is shown in particular by FIG. 11. The LP water delivery manifold 134a comprises a pair of adjuster plates 172, 174, one adjuster plate coupled to each end of the air blade frame 158. The adjuster plates 172, 174 are fixed to the second frame 138, part of which is shown in FIG. 9. The adjuster plates 172, 174 may be adjusted by an operator to vary a distance D2 between the LP nozzles 168a, 168b, 168c, 168d and the pipe sections 2, 4 (measured from the field joint coating 24) and/or accommodate pipe sections 2, 4 or different diameters. The LP water deliver manifold 134a remains substantially parallel to the axis A-A notwithstanding a change in distance D2.

[0064] Referring to FIG. 12, there is shown the HP water delivery manifold 140a in more detail, it being understood that the other HP water delivery manifold 140b has the same basic construction. The HP water delivery manifold 140a comprises a high pressure water inlet 176 fluidly coupled to a high pressure (HP) water pump (not shown) upstream of the HP water inlet 176. In between the HP water pump and the HP water delivery manifold 140a is a filter (not shown) for filtering and cleaning water destined for the HP water delivery manifold 140a. The HP water pump is capable of pumping a volumetric water flow of approximately 50 litres/minute of water at a pressure of approximately 100 Bar to each of the HP water delivery manifolds 140a, 140b i.e. a total volumetric water flow of approximately 100 litres/minutes of water. The HP water pump is standard equipment controlled by the interface 118 which is not described in any more detail. The HP water delivery manifold 140a comprises three T-junctions 178a, 178b, 178c. The HP water delivery manifold 140a and its three T-junctions 178a, 178b, 178c divide the water flow from the HP water inlet 176 evenly between three high pressure water outlets 180a, 180b, 180c, each downstream of a respective T-junction, and a fourth HP water outlet 180d coupled to the end of the HP water delivery manifold 140a. Each HP water outlet is a HP nozzle 180a, 180b, 180c, 180d fixed to the underside of a HP water manifold frame 182. Each HP nozzle 180a, 180b, 180c, 180d sprays a respective jet of water from the underside of the HP water manifold frame 182 in the direction of a field joint 6, 8, 10 in the enclosure 102. In use, each HP nozzle 180a, 180b, 180c, 180d sprays a HP water jet 184 with a spray plane fanning out at about 40 degrees. The edges of adjacent HP water jets 184 merge into a band spanning the field joint 6, 8, 10 in the enclosure 102. The HP water delivery manifold 140a comprises a pair of adjuster plates 186, 188, one adjuster plate coupled to each end of the air blade frame 158. The adjuster plates 186, 188 are fixed to the second frame 138, part of which is shown in FIG. 12. The adjuster plates 186, 188 may be adjusted by an operator to vary a distance D3 between the HP nozzles 180a, 180b, 180c, 180d and the pipe sections 2, 4 (measured from the bare metal of the field joint 6, 8, 10) and/or accommodate pipe sections 2, 4 or different diameters. The HP water deliver manifold 140a remains substantially parallel to the axis A-A notwithstanding a change in distance D3.

[0065] Referring to FIG. 13, there is shown the induction heater plate 142 in more detail, it being understood that the other induction heater plate 144 has the same basic construction. The induction heater plate 142 has a generally rectangular outer profile, when viewed from above. The induction heater plate 142 is electrically coupled by an electrical cable 146 to an alternating electrical power supply (not shown) having, and purely for the purpose of example, an output variable up to 110 kW and a frequency of between 10 and 25 kHz to produce an induction heating effect in the induction heater plates 142. Alternating electrical power supplies for induction heaters are standard parts well known in this field of technology. Operation of the alternating electrical power supply to the induction heater plates 142, 144 is controlled by the interface 118.

[0066] The induction heater plate 142 is fixed to the underside of an induction heater frame 190 which is coupled to the second frame 138 via a pair of induction heater coupling mechanisms 192, 194. Also fixed to the underside of the induction heater frame 190 is a pair of rollers 196, 198, one at each opposite axial end of the induction heater frame 190. One induction heater coupling mechanism 192, 194 is located at each axial end of the induction heater frame 190. The induction heater coupling mechanisms 192, 194 may be adjusted by an operator to vary a distance between the induction heater plate 142 and a field joint 6, 8, 10 in the enclosure 102 and/or accommodate pipe sections 2, 4 or different diameters. The rollers 196, 198 are rotatable about an axis parallel to the axis A-A. The induction heater coupling mechanisms 192, 194 resiliently bias the induction heater frame 190 a short radial distance towards the axis A-A to bring each roller 196, 198 into contact with a respective factory-applied coating 12, 14 of pipe sections 2, 4 in the enclosure 102. The induction heater coupling mechanisms 192, 194 act independently of each other to maintain the induction heater underside 142a parallel to outer cylindrical shape of the field joint 6, 8, 10 in the enclosure 102 which, in normal circumstances, is also parallel to the axis A-A. In use, the rollers 196, 198 follow the shape of the pipe sections 2, 4 and, in combination with the induction heater coupling mechanisms 192, 194, move the induction heater underside 142a in a way that compensates for different diameters of pipe sections 2, 4 and/or deviations from a purely cylindrical outer shape. This tolerance ensures that the induction heater plate 142 is maintained at about the right height (approximately 10 mm to 20 mm) above the field joint 6, 8, 10 for optimum induction heating and/or to avoid the welded joint 6 which can stand 5 mm proud of that section of pipeline.

[0067] It is important that the induction heater plates 142, 144 are electrically insulated from the second frame 138 and surrounding structures mounted thereupon. The induction heater plates 142, 144 are coated or wrapped with an insulating material.

[0068] The induction heater plates 142, 144 are sized and positioned so that they may heat a standard length of field joint 6, 8, 10 section of pipeline (i.e. having an axial length of approximately 300 mm in the example shown, although it can be up to a length of 725 mm or more) up to, but not including, the chamfered portions 20, 22 of the factory-applied coatings 12, 14.

[0069] Each induction heater frame 190 comprises a pyrometer 200 for measuring the surface temperature of the field joint 6, 8, 10 section of pipeline in its vicinity. These temperatures are communicated to the interface 118 in real time. The interface 118 displays these temperatures to the operator.

[0070] Referring to FIG. 14, there is shown a water circuit for circulating water to and from the machine 100. The water circuit comprises the machine 100, the water extraction hose 112, the bath 300 and the water delivery hose 114. The hopper 110 collects water from inside the enclosure 102 and delivers it to the water extraction hose 112 through which is flows, either under gravity or by pumping, to the bath 300 where the water is collected. Submerged in the bath water is a submergible pump 302 fluidly coupled to the water delivery hose 114. The submergible pump 302 is powered by a control box 304 operated by the interface 118. Water pumped by the submergible pump 302 flows from the bath 300, through the water delivery hose 114 and to the water delivery port 116 at the top of the enclosure 102. Once inside the enclosure 102, water from the delivery hose 114 flows through internal pipes to either the LP water pump, in the case of the first embodiment of the machine 100, or the HP water pump, in the case of the second embodiment of the machine 100.

[0071] Water delivered to the first embodiment of the machine 100 should to be chilled to about five degrees Celsius for the purpose of quenching a field coating 24 in the enclosure 102. For this purpose, the bath 300 has a chiller circuit 306 comprising a refrigeration unit 308 for delivery of cooled refrigerant to, and recovery of warmed refrigerant from, a submersible heat exchanger 310 in the bath water. The refrigeration unit 308 may be powered by a shore supply. The refrigeration unit 308 and its cooling temperature may be controlled by the interface 118 or, alternatively, it may be independently set by the operator to chill the bath water to a particular temperature. In use, the heat exchanger 310 is submerged in the water recovered from the enclosure 102 and cools it, while in the bath 300, to about five degrees Celsius ready for re-use. The cooled bath water is pumped by the submergible pump 302 to the enclosure 102. The submergible pump 302 has, at its inlet, a filter to ensure that any solid matter, such as debris recovered by the hopper 110 and delivered to the bath 300, does not pass.

[0072] Water delivered to the second embodiment of the machine 100 need not be cooled for the purpose of jet washing a welded field joint 6, 8, 10 section of pipeline in the enclosure 102. The chiller circuit 306 is not needed and it may be discarded or inoperative. Optionally, the bath 300 may not be present if the water delivery hose 114 is connected to a tap and the water extraction hose 112 is connected to a drain, for example. Nevertheless, if the bath 300 is present, it is useful for containment of water and collection of debris recovered by the hopper 110 and it enables both embodiments of the machine 100 to be used where taps and drains are not readily available.

[0073] Operation of the first and second embodiments of the machine 100 shall now be described, with reference to FIGS. 1 to 14. The first embodiment of the machine 100 is configured for low water pressure water quenching processes to stabilize and toughen a field joint coating and optionally prepare it for integrity testing. The second embodiment of the machine 100 is configured for high pressure water jet wash processes to prepare a welded field joint 6, 8, 10 section of pipeline for a field joint coating later in the manufacturing process.

[0074] Referring to the first embodiment of the machine 100, as is shown particularly in FIGS. 4 and 5, a new field joint coating 24, which is still relatively hot, is fed through the pipeline holes 104a, 104b of the machine 100 to the middle of the first frame 124. This can be visually checked by an operator looking though the windows 108a, 108b. The weight of the pipe sections 2, 4 is supported on each side of the enclosure 102 by external supports (not shown). The enclosure 102 surrounds the field joint coating 24 around the field joint 6, 8, 10 section of pipeline without performing a support function. An operator seals the enclosure 102 with stationary rubber seals fixed around the pipeline holes 104a, 104b.

[0075] The operator selects a quenching process from the menu presented by the human/machine interface 118 and starts the machine 100.

[0076] The three air delivery manifolds 136a, 136b, 136c are activated to blow air blades 160 of compressed air at the field joint coating 24. At the same time, the electric motor 122 is activated to rotate the cylindrical first frame 124, and all components mounted thereto, about the axis A-A in oscillating sweeps of 120 degrees (to expose the whole field joint coating 24 to the compressed air of the air blades 160) in both directions of double-headed arrow B. This forms, assisted by coanda effect, a blanket of air around the field joint coating 24. The air blades 160 begin cooling the field joint coating 24.

[0077] After about sixty seconds, the three air delivery manifolds 136a, 136b, 136c are deactivated and the three LP water delivery manifolds 134a, 134b, 134c are activated. The four LP nozzles 168a, 168b, 168c, 168d on each of the LP water delivery manifolds 134a, 134b, 134c ensure that the whole surface of the field joint coating 24 is covered by water spray cooled to about five degrees Celsius by the chiller circuit 306. Each LP nozzle provides 10 litres/minute volumetric flow rate at approximately 4 Bar pressure.

[0078] After about three minutes of water spray, the three LP water delivery manifolds 134a, 134b, 134c are deactivated. Optionally, for a period of between 40 and 60 seconds, the three air delivery manifolds 136a, 136b, 136c may be reactivated to blow water remaining from the quenching operation from the field joint coating 24 and contribute to drying the field joint coating 24 before it leaves the enclosure 102.

[0079] Throughout the quenching process, water used to quench the field joint coating 24 falls, under gravity, into the hopper 110 where it flows into the water extraction hose 112 to be delivered to the bath 300 outside the enclosure 102 for cooling and reuse. After about forty to sixty seconds, the three air delivery manifolds 136a, 136b, 136c are deactivated. The operator removes the stationary rubber seals from around the pipeline holes 104a, 104b. The quenched field joint coating 24 is fed through the middle of the first frame 124 and out the pipeline holes 104a, 104b, of the machine 100. Again, this can be visually checked by the operator looking though the windows 108a, 108b. The enclosure 102 is now ready to receive another field joint coating 24 around a field joint 6, 8, 10 section of pipeline.

[0080] Referring to the second embodiment of the machine 100, as is shown particularly in FIGS. 6 and 7, a welded joint 6 of two factory-coated pipe sections 2, 4 is fed through the pipeline holes 104a, 104b of the machine 100 to the middle of the second frame 138. This can be visually checked by an operator looking though the windows 108a, 108b. The weight of the pipe sections 2, 4 is supported on each side of the enclosure 102 by external supports (not shown). The enclosure 102 surrounds the field joint 6, 8, 10 section of pipeline without performing a support function. An operator seals the enclosure 102 with stationary rubber seals fixed around the pipeline holes 104a, 104b.

[0081] The operator selects a washing process from the menu presented by the human/machine interface 118 and starts the machine 100.

[0082] The three HP water delivery manifolds 140a, 140b, 140c are activated to spray the HP water jets 184 at the field joint 6, 8, 10, each HP nozzle 180a, 180b, 180c, 180d providing 12.5 litres/minute volumetric flow rate at 100 Bar pressure. At the same time, the electric motor 122 is activated to rotate the cylindrical second frame 138, and all components mounted thereto, about the axis A-A in oscillating sweeps of approximately 120 degrees (to expose the whole field joint 6, 8, 10 to the HP water jets 184 and the air blades 160) in both directions of double-headed arrow B. The HP water jets 184 dislodge debris and wash it away from the field joint 6, 8, 10.

[0083] After thirty seconds, the three HP water delivery manifolds 140a, 140b, 140c are deactivated and three air delivery manifolds 136a, 136b, 136c are activated. The three air delivery manifolds 136a, 136b, 136c blow air blades 160 of compressed air at the field joint 6, 8, 10. The air blades 160 aid removal of the dislodged debris and any excess water and help dry the field joint 6, 8, 10 before it leaves the enclosure 102. After a period of about sixty seconds, the three air delivery manifolds 136a, 136b, 136c are deactivated. Water and debris washed from the field joint 6, 8, 10 falls, under gravity, into the hopper 110 where it flows into the water extraction hose 112 to be delivered to the bath 300 outside the enclosure 102 for reuse, disposal or recycling.

[0084] Optionally, the second embodiment of the machine 100 may be equipped with the induction heater plates 142, 144. If so, once the three air delivery manifolds 136a, 136b, 136c are deactivated and the washing process is complete, the induction heater plates 142, 144 are activated. The rollers 196, 198 contact the factory-applied coatings 12, 14 of pipe sections 2, 4. Heating is automatically tuned by the alternating electrical power supply according to the distance between the induction heater plates 142, 144 and the bare steel field joint 6, 8, 10. The induction heater plates 142, 144 are configured to heat the field joint 6, 8, 10 section of pipeline between the chamfered portions 20, 22 of the factory-applied coatings 12, 14. The induction heater plates 138, 142 need only heat the surface of the field joint 6, 8, 10 to a shallow depth (i.e. about 0.3 mm) to temperature of about 110 degrees Celsius. The pyrometers 200 are activated to monitor the surface temperature of the field joint 6, 8, 10 section of pipeline. Once the field joint 6, 8, 10 is sufficiently warm and dry, as determined by the interface 118, the induction heater plates 142, 144 are deactivated. The field joint 6, 8, 10 is now ready for a field joint coating 24.

[0085] Once the three HP water delivery manifolds 140a, 140b, 140c the three air delivery manifolds 136a, 136b, 136c and, optionally, the induction heater plates 142, 144 are deactivated, the operator removes the stationary rubber seals from around the pipeline holes 104a, 104b. The washed field joint 6, 8, 10 section of pipeline is fed through the middle of the second frame 138 and out the pipeline holes 104a, 104b of the machine 100. Again, this can be visually checked by the operator looking though the windows 108a, 108b. The enclosure 102 is now ready to receive another field joint 6, 8, 10 section of pipeline.