Field of the Invention

[0001 ] The present invention relates to the hot tapping of hydraulic systems; that is, the creation of a hole within hydraulic tubing while the hydraulic fluid remains under pressure. The present invention has been designed for operation in underwater environments by Remotely Operated Vehicles (ROVs), but is considered to have wider application.

Background to the Invention

[0002] There are a number of situations where hot tapping of underwater hydraulic systems may be required. These include the supply of additional hydraulic fluid to a system; the expansion of a system through the inclusion of branch lines; and the installation of measuring devices.

[0003] Generally, underwater hydraulic systems contain tubing made of extremely high-strength materials, such as Inconel 625. The creation of holes in such tubing requires the application of significant force. It must, however, be achieved without significant bending of the tubing.

[0004] Crucially, hot tapping of such tubing must not introduce foreign material, such as swarf, into the hydraulic fluid within the tube. It is therefore not advisable to drill into hydraulic tubing for the purpose of hot tapping.

[0005] Other requirements and desiderata will be readily identifiable to a skilled worker. Any tool used for hot tapping, particularly in a remote underwater location, must be able to be readily positioned at a preferred location along the hydraulic tubing. It must be able to be fixed in this position relative to the tubing, such that the action of pressurised fluid from within the tubing and water pressure from outside the tubing will not dislodge the tool. It is preferred that the tool be able to stay in position indefinitely, as sealing of the hot tapped hydraulic tooling may not be possible. It is also preferred that the tool provides clear visual confirmation to a remote operator regarding the status of its operation. [0006] The present invention has been developed in light of these considerations.

Summary of the Invention

[0007] According to one aspect of the present invention there is provided a tool for hot tapping a hydraulic system, the hydraulic system including a generally cylindrical tube having a sidewall, the tool including a punch arranged to orient generally radially relative to the tube, the punch having a penetrating end shaped to penetrate the tube, the tool further including an urging means arranged to force the punch into the sidewall of the tube.

[0008] The tool may have a locating channel arranged to locate about the tube.

[0009] According to a second aspect of the present invention there is provided a tool for hot tapping of a hydraulic system, the tool including a locating channel arranged to receive a tube, the locating channel having an axial direction and a transverse direction perpendicular to the radial direction, the tool including a punch arranged to orient generally in the transverse direction relative to the locating channel, the punch having a penetrating end, the tool further including an urging means arranged to force the punch into the locating channel.

[0010] According to a third aspect of the present invention there is provided a method of hot tapping a hydraulic system, the hydraulic system including a generally cylindrical tool having a sidewall, the tool having a locating channel and a punch, the punch having a penetrating end and an urging means, the method including the steps of positioning the tool such that its locating channel is located about the tube, and operating the urging means to urge the penetrating end of the punch into the sidewall of the tube.

[001 1 ] The urging means is preferably a hydraulic piston. Alternatively, the urging means could be mechanically driven, such as by using a threaded member. [0012] In a preferred embodiment, the penetrating end has a cutting edge which is oriented at between 30° and 60° to an axial direction of the punch. It is anticipated that the penetrating end will have a cutting edge oriented at 45° to the axial direction of the punch.

[0013] The punch is preferably a cylindrical rod, with its cutting edge formed by bevelling the end of the rod at about 45°. It will be appreciated that this forms a cutting edge having a midline which extends across a diameter of the rod, a leading portion located on one side of the midline and extending axially forward of the midline and a trailing portion located on the other side of the midline and extending axially rearward of the midline.

[0014] In some circumstances it is preferred that the punch is configured such that the midline of the cutting edge is parallel to a central axis of the tube. In this way, the leading portion of the cutting edge will penetrate the tube along a chord.

[0015] In other circumstances it is preferred that the punch is configured such that the midline of the cutting edge is perpendicular to the central axis of the tube.

[0016] The locating channel may include an indicating arm, such that correct location of the tube within the locating channel causes movement of the indicating arm. It is anticipated that the indicating arm may be linked to a readily viewable indicator.

[0017] The tool may have at least one attachment means for clamping of the tool to the tube. In a preferred embodiment, the tool has two attachment means: a primary clamping means which may be hydraulic, and a holding means which is mechanical. In this way the primary clamping means may be used to fix the tool in its desired location relative to the tube, and the mechanical means engaged to ensure continued attachment of the tool to the tube even in the event of loss of hydraulic pressure. [0018] The tool may have a hydraulic lock associated with a hydraulic clamping means. The hydraulic lock may be deployable to seal against hydraulic cylinders once the hydraulic clamping means is actuated, so as to maintain the hydraulic clamping means in position in the event of loss of external hydraulic pressure.

[0019] The hydraulic system may be located under water. In one

embodiment of the invention, the tool may be located aboard an ROV. In an alternative embodiment, the tool may be lowered to a desired depth and then positioned about the tube using ROV assistance.

Brief Description of the Drawings

[0020] It will be convenient to further describe the invention with reference to preferred embodiments of the present invention. Other embodiments are possible, and consequently the particularity of the following discussion is not to be understood as superseding the generality of the preceding description of the invention. In the drawings:

[0021 ] Figure 1 is a front schematic isometric view of a tool for hot tapping a hydraulic system in accordance with a first embodiment of the present invention;

[0022] Figure 2 is a rear schematic isometric view of the tool of Figure 1 ;

[0023] Figures 3-9 are sequential partial cross sectional views of the tool of Figure 1 during use;

[0024] Figure 10 is a side view of a tool for hot tapping a hydraulic system in accordance with a second embodiment of the present invention;

[0025] Figure 1 1 is a cross section through the tool of Figure 10;

[0026] Figure 12 is a front perspective of a tool for hot tapping a hydraulic system in accordance with a third embodiment of the present invention; and [0027] Figure 13 is a cross section through the tool of figure 13.

Detailed Description of Preferred Embodiments

[0028] Referring to Figures 1 to 10, there is shown a tool 10 for the hot tapping of hydraulic systems. The tool 10 has a body portion 12 having a generally longitudinal direction 14 and a transverse direction 16. The tool 10 has a first end 18, a second end 20, a top surface 22 and a bottom surface 24.

[0029] A transverse channel 26 extends across the bottom surface 24. The transverse channel 26 has a generally V-shaped introductory portion, which narrows inwardly from the bottom surface 24 before opening into a transverse locating channel 28.

[0030] The arrangement is such that the tool 10 can be brought into an initial position as shown in Figure 3 whereby the bottom surface 24 locates over a tube 50 of an underwater hydraulic system. The tool 10 can then be manoeuvred such that the transverse channel 26 locates about the tube 50. Lowering of the tool 10 then causes the tube 50 to be received within the locating channel 28.

[0031 ] The locating channel 28 is associated with two spring-loaded indicating arms 32. The indicating arms 32 each have a lower end 34 which extends into the locating channel 28, and an upper end 36 on the top surface 22 of the tool 10. The upper end 36 is associated with an indicator. The arrangement is such that when the tube 50 is located within the locating channel 28 it pushes against the lower ends 34 of the indicating arms, causing their upper ends 36 and associated indicators to extend above the top surface 22 of the tool 10. This allows a remote operator visual confirmation that the tool 10 is correctly positioned relative to the tube 50. This is shown in Figure 4. [0032] The tool 10 has a primary clamping means, operated by means of the supply of hydraulic fluid through a first fluid port 40 to a clamping piston 42. The clamping piston 42 is connected to a bearing member 44.

[0033] The bearing member 44 has an outer surface including a

transversely extending, concave, tube engaging channel 46. The

arrangement is such that the supply of hydraulic fluid to the clamping piston 42 causes the bearing member 44 to move in the longitudinal direction 14, engaging the tube 50 within the channel 46 and locking the tube 50 in position against a curved front wall 48 of the locating channel 28. This position is shown in Figure 5.

[0034] The primary clamping means has a hydraulic lock, including a locking piston 52 operated by supply of hydraulic fluid through a second fluid port 54. Movement of the locking piston 52 acts to seal off the first fluid port 40, securing the clamping piston 42 in its locked position. This is shown in Figure 6.

[0035] The tool 10 has a mechanical holding means 60 associated with the clamping piston 42. The holding means 60 is formed by a threaded locking member 62 which extends inwardly of the second end 20 of the tool 10. The threaded member 62 can be driven by an external rotation force in order to be brought into contact with the clamping piston 42, thus holding the clamping piston 42 and therefore the bearing member 44 in the locked position relative to the tube 50. When the holding means 60 is engaged in this matter, even a loss of hydraulic pressure about the clamping piston 42 will not cause relative movement of the tool 10 and the tube 50. This is the arrangement shown in Figure 7.

[0036] The tool 10 has a punch 70. The punch 70 is formed by a cylindrical rod, located between the first end 18 of the tool 10 and the locating channel 28. The punch has a penetrating end 72, formed by bevelling the end of the rod at 45°. This creates a cutting surface. It will be appreciated that the angle of the penetrating end may be between about 30° and about 60° depending on the particular circumstances in a given application.

[0037] The punch 70 is arranged such that a midline of the cutting surface; that is, the line across the cutting surface which passes through the centre and is perpendicular to the axis of the rod, is oriented in the transverse direction 16. A leading edge of the penetrating end 72 is oriented on the lower side, closer to the bottom surface 24, and a trailing edge is oriented on the upper side, closer to the top surface 22.

[0038] The punch 70 is positioned relative to the front wall 48 of the locating channel 28 so that axial movement of the punch 70 causes the midline of the cutting surface to move towards a central axis of the tube 50.

[0039] The punch 70 is activated by an activating piston 74, operated by the supply of hydraulic fluid through a third fluid port 76.

[0040] When fluid is thus supplied, the punch 70 is moved axially, such that it first contacts a sidewall of the tube 50, and then penetrates the sidewall of the tube 50. The cutting action is offset relative to a radius of the tube 50, with the leading edge of the rod 70 acting along a chord of the tube almost tangential to the inner side wall. This causes the punched out material to bend away from the penetrating end 72 of the punch 70, ultimately being folded back against an inner side wall of the tube 50 and not significantly affecting fluid flow within the tube 50. This punching action can be seen in Figure 8.

[0041 ] Once the required hole has been made within the tube 50, the punch 70 must be withdrawn. This is achieved via the application of hydraulic fluid through a fourth fluid port 78 to the inside of the activating piston 74, as shown in Figure 9.

[0042] The tool 10 has a hydraulic access port 80, which connects with the space vacated by the penetrating end 72 of the punch 70. Once the punch 70 has been withdrawn, the hydraulic access port 80 is in fluid connection with the inside of the tube 50. It can thus be used for any desired operation, including supply of further fluid; pressure testing; or as a bridge to further hydraulic circuits.

[0043] Referring to Figures 1 1 and 12, there is shown an alternative tool 1 10 for the hot tapping of hydraulic systems. The tool 1 10 is effectively a simplified version of the tool 10, and is arranged for ready deployment by an ROV.

[0044] The tool 1 10 has a body portion 1 12 sim ilar to that of the tool 10. The tool 1 10 has a first end 1 18, a second end 120, a top surface 122 and a bottom surface 124.

[0045] A transverse channel 126 extends across the bottom surface 124. The transverse channel 126 is generally L-shaped, such that the tool 1 10 can be positioned whereby a tube 150 can be positioned within an inside leg of the L-shape, against a curved foot 148 of the L-shape.

[0046] The tool 1 10 has a primary clamping means, operated by means of the supply of hydraulic fluid through a first fluid port 140 to a clamping piston 142. The clamping piston 142 is connected to a bearing member 144.

[0047] The bearing member 144 has an outer surface including a transversely extending, concave, tube engaging channel. The arrangement is such that the supply of hydraulic fluid to the clamping piston 142 causes the bearing member 144 to move in the longitudinal direction, engaging the tube 150 within the channel and locking the tube 150 in position against the curved foot 148 of the transverse channel 126.

[0048] The tool 1 10 has a mechanical holding means 160 associated with the clamping piston 142. The mechanical holding means 160 works in the same fashion as the mechanical holding means 60 of the tool 10. [0049] The tool 1 10 has a punch 170, which operates in a similar fashion to the punch 70 of the tool 10.

[0050] The punch 170 is activated by an activating piston 174, operated by the supply of hydraulic fluid through a third fluid port 176.

[0051 ] The tool 1 10 has a hydraulic access port 180. Once the punch 170 has been withdrawn, the hydraulic access port 180 is in fluid connection with the inside of the tube 150.

[0052] Referring to Figures 12 and 13, there is shown a further alternative tool 210 for the hot tapping of hydraulic systems. The tool 210 has been designed for larger tubes 250, and is arranged to be deployed by crane from a vessel; lowered to a seabed for use, and then moved into position and operated using an ROV or controlled by a diver. The mass of the tool 210 is offset with sufficient flotation medium to achieve close to neutral buoyancy.

[0053] The tool 210 has a body portion 212. The tool 210 has an upper end 218, a lower end 220, a front surface 222 and a rear surface 224.

[0054] A transverse channel 226 extends across the rear surface 224, near the lower end 220. The transverse channel 226 is generally L-shaped, such that the tool 210 can be positioned whereby the tube 250 can be positioned within an inside leg of the L-shape, against a curved foot 248 of the L-shape.

[0055] The tool 210 has a primary clamping means, operated by means of the supply of hydraulic fluid to two parallel clamping pistons 242. The clamping pistons 242 are connected to a bearing member 244.

[0056] The bearing member 244 has an outer surface including a

transversely extending, concave, tube engaging channel 246. The

arrangement is such that the supply of hydraulic fluid to the clamping pistons 242 causes the bearing member 244 to move downwards, engaging the tube 250 within the channel 246 and locking the tube 250 in position against the curved foot 248 of the transverse channel 226.

[0057] The tool 210 has a mechanical holding means 260 associated with each clamping piston 242. The mechanical holding means 260 works in the same fashion as the mechanical holding means 60 of the tool 10.

[0058] The tool 210 has a punch 270. The punch 270 is formed by a cylindrical rod, located between the upper end 218 of the tool 210 and the transverse channel 226. The punch 270 is positioned between the two clamping pistons 242. The punch has a penetrating end 272, formed by bevelling the end of the rod at 45°. This creates a cutting surface.

[0059] The tool 210 is arranged to penetrate a much larger tube 250 than the tool 10. In these circumstances, the punched out material does not significantly impact fluid flow within the tube 250, and the punch 270 can be positioned such that a midline of the cutting surface is perpendicular to a central axis of the tube 250. This is particularly effective where flow is oneway, and the punched out material can be bent in the direction of fluid flow.

[0060] The punch 270 is activated by an activating piston 274.

[0061 ] When fluid is supplied to the activating piston, the punch 270 is moved axially (i.e., downwardly), such that it first contacts a sidewall of the tube 250, and then penetrates the sidewall of the tube 250.

[0062] Once the required hole has been made within the tube 250, the punch 270 must be withdrawn. This is achieved in a similar fashion to that of the tool 10.

[0063] Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.