AU2016343299B2

AU2016343299B2 - Subsea torque tool

Info

Publication number: AU2016343299B2
Application number: AU2016343299A
Authority: AU
Inventors: Jeremy DOBRA; Sean KILLEN; Laszlo LICSIK; Hans Raub
Original assignee: Total Marine Tech Pty Ltd
Current assignee: TOTAL MARINE TECHNOLOGY Pty Ltd
Priority date: 2015-10-22
Filing date: 2016-10-21
Publication date: 2022-07-14
Anticipated expiration: 2036-10-21
Also published as: AU2022252790A1; WO2017066848A1; AU2016343299A1

Abstract

An electrically powered torque tool for remotely operated underwater use is disclosed. The tool includes a control circuit with feedback loops located within a Remotely Operated Vehicle, and a gearing arrangement including a gear ratio in the order of 500:1.

Description

"SUBSEA TORQUE TOOL"

Field of the Invention

[0001 ] The present invention relates to a subsea torque tool, such as those deployed using a Remotely Operated Vehicle (ROV).

Background to the Invention

[0002] Traditionally, torque tools for deployment on ROVs are hydraulically powered, with the ROV being connected to the surface by an umbilical line.

[0003] Such hydraulic tools have limitations in their use. It is difficult to make precise calibrations of movement and torque using remotely operated hydraulic torque tools, particularly over a large range of torque. In addition, hydraulic torque tools are often heavy (for instance, in the order of 40kg), and this presents significant handling difficulties when above water.

[0004] Attempts have been made to reduce the size of hydraulic torque tools, enabling them to be deployed in smaller ROVs. This has proved difficult to achieve. A torque tool for underwater use is generally required to provide a torque output with a range in the order of 50Nm to 3000Nm. This range dictates the minimum size of the hydraulic torque tool.

[0005] Further issues arise in the verification of hydraulic torque tool operation. As the torque tool wears, its response to controls and system pressure will change. In order to maintain calibration of such a tool expensive maintenance is required. If this is not adequately performed, it can be difficult to determine whether or not a hydraulic torque tool has completed a task in a remotely operated underwater environment. For example, it may be difficult to determine from the surface whether or not a tool has moved through its full range of movement.

[0006] It is considered that use of an electrically powered torque tool may assist in overcoming these limitations. The applicant is aware of occasional previous attempts to create a useful electric torque tool, but these attempts have not been able to produce a torque tool with sufficient power to meet peak power demand for torque tool operation, particularly above 2000Nm.

[0007] The present invention has been developed in light of this

background.

Summary of the Invention

[0008] According to one aspect of the present invention there is provided an electrically powered torque tool for use in a remote underwater

environment, the torque tool including an electric motor, a gearing

arrangement, and a torque applying portion, the supply of electricity to the electric motor acting to drive the torque applying portion via the gearing arrangement, wherein the gearing arrangement has a gear ratio greater than 500 to 1 . Advantageously, this allows a relatively small electric motor to generate large torque when required, albeit at low speeds.

[0009] According to a second aspect of the present invention there is provided a control means for an electrically powered torque tool, the control means including a process controller which is arranged to communicate with a remotely located operator, the process controller being arranged to control the supply of electrical current to an electric motor within the torque tool, wherein a feedback means is arranged to provide information to the process controller regarding the output of the torque tool. Advantageously, this allows the process controller to control torque output without a time lag caused by sending data to the remotely located operator.

[0010] The feedback means may include at least one, and preferably two, strain gauges. The strain gauge(s) may be powered through a polarity changing power supply.

[001 1 ] The feedback means may include a resolver coupled to the motor.

[0012] The feedback means may include a temperature sensor and/or a water ingress sensor. A pitch/roll sensor may also be included. [0013] The remotely operated locator may be a computer.

[0014] It is preferred that the process controller is located outside the torque tool. In a preferred embodiment, the process controller may be located on an ROV, arranged to receive data from the feedback means located on the torque tool, and arranged to control the supply of electric current to the torque tool.

[0015] According to a third aspect of the present invention there is provided a latching mechanism associated with an electrically powered torque tool, the latching mechanism including an electromagnetic actuator, the electromagnetic actuator including a first fixed coil and second fixed coil, the first and second fixed coils being spaced along a main axis, the actuator including a driving shaft on which a magnetically responsive element is fixed, the driving shaft being arranged to pass through the second fixed coil, the driving shaft extending along the main axis, the driving shaft being mechanically connected to a latch, wherein the supply of electrical current to the first and second fixed coils generates a magnetic field which acts on the magnetically responsive element in an axial direction causing the driving shaft to operate the latch.

[0016] It is preferred that the magnetically responsive element be a permanent magnet. Alternatively, the magnetically responsive element may be a third coil.

[0017] It will be appreciated that the first and second coils are wired inversely, such that when current flows in one direction the first coil repels the magnetically responsive element and the second coil attracts the magnetically responsive element.

[0018] It is preferred that the second coil contains more windings than the first coil, and thus provides a stronger magnetic field. Brief Description of the Drawings

[0019] 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:

[0020] Figure 1 is a perspective of a torque tool head in accordance with the present invention;

[0021 ] Figure 2 is an end view of the torque tool head of Figure 1 ;

[0022] Figure 3 is a side view of the torque tool head of Figure 1 ;

[0023] Figure 4 is a cross section through the torque tool head of Figure 1 ;

[0024] Figure 5 is a schematic view of a control system for the torque tool head of Figure 1 ;

[0025] Figure 6 is a schematic view of a torque head control and sensors within the torque tool head of Figure 1 ;

[0026] Figure 7 is a perspective of a latching mechanism for use with the torque tool head of Figure 1 ;

[0027] Figure 8 is a cross section through the latching mechanism of Figure 7, shown in an open configuration; and

[0028] Figure 9 is a cross section through the latching mechanism of Figure 7, shown in a closed configuration.

Detailed Description of Preferred Embodiments

[0029] Referring to the Figures, Figures 1 to 4 show a torque tool 10. The torque tool 10 is generally cylindrical, with an operating end 12 and an ROV coupling end 14. [0030] A rear housing 16 extends from the ROV coupling end 14 to a handle base 18. The rear housing 16 encloses an electric motor 20, which is coupled at a forward end to a gearing arrangement in the form of a gear box 22, and at a rear end to a resolver 24.

[0031 ] The gear box 22 has a similar diameter to that of the electric motor 20, in order to make efficient use of the space available within the rear housing 16. The gear box 22 has an extremely large gear ratio, in the range of 500: 1 to 1000: 1 . In this way a relatively large torque can be generated (albeit at very low speeds) from a relatively small electric motor.

[0032] The torque tool 10 has a nose cone 26 at the operating end 12. The nose cone 26 incorporates a torque-applying member 28.

[0033] The torque tool 10 has a control means, including a process controller 30. The process controller 30 in the preferred embodiment is a dual microprocessor. The process controller 30 is arranged to communicate with a remotely located operator; that is, with a controller application located on a computer 32 above the ocean surface. The controller application may be a graphical user interface (GUI) system which can provide details of the torque tool operation to an operator. The process controller 30 may be located within an ROV from which the torque tool 10 is deployed.

[0034] The process controller 30 is arranged to control a motor controller 34. The motor controller 34 regulates the supply of electrical current to the electric motor 20 via a motor drive line 54.

[0035] Electric current can be supplied to the electric motor 20 via the motor controller 34 from the best available power source. Possible power sources include an on-board battery 36, which may be arranged to charge from a limited ROV power source 38 via a battery charger 40. Alternatively, if a high power DC electric supply 42 is available to the ROV then this power supply may be used directly. If a high power AC electric supply 44 is available, then a rectifier 46 incorporating power factor correction may be used to provide the necessary electric current. It is proposed that the process controller 30 may be arranged to set a suitable VBUS voltage for the motor controller 34, in order to achieve an optimal motor operating condition based on the required torque and speed.

[0036] The torque tool 10 includes a variety of feedback means arranged to provide information to the process controller 30 regarding the output of the torque-applying member 28 and the performance of the electric motor 20. These include dual strain gauges 50 to directly measure output torque. The strain gauges are excited through a polarity changing supply in order to eliminate residue torque and offset effects, as well as reducing low

frequency noise. Pitch and roll angle sensors 56 are also used to monitor the position of the torque tool 10.

[0037] The resolver 24 is used to supply information about the motor performance to the process controller 30 via a resolve information line 52. This provides for close control of angle of rotation, and allows for minimal torque ripple during motor rotation. In the embodiment shown, the resolver 24 is an oil-filled resolver. It is anticipated that this could be replaced in an alternative embodiment by other sensors such as a Hall sensor.

[0038] Further condition feedback is provided through voltage monitors 58, temperature monitors 60, and water ingress sensors 62. These sensors provide information to an on-board microprocessor 64 on the torque tool 10, which relays the information via the dataline 66 to the on-board process controller 30 on the ROV for processing.

[0039] It will be appreciated that use of the on-board process controller 30 allows for fast local control of important parameters such as torque and speed, eliminating the potentially long delay caused by requiring surface instruction and control. This is particularly important over long distances, and where data bandwidth is limited. [0040] The on-board process controller 30 is programmed to consider restrictions in available power and to adapt torque and speed trajectory accordingly. The use of the electric motor 20 with a high ratio gear box 22 allows for ready control of output torque, which is largely proportional to input current.

[0041 ] The torque tool 10 is arranged to be used in conjunction with a latching mechanism 70 as shown in Figures 7 to 9. The latching mechanism 70 includes an electrically actuated portion 72 mounted to a latching body 74. The electrically actuated portion 72 is connected to the ROV and ultimately to the remotely located operator by means of an operating cable 76.

[0042] The electrically actuated portion 72 includes a first fixed coil 80 and a second fixed coil 82. The first and second fixed coils 80, 82 are spaced along a main axis of the electrically actuated portion 72.

[0043] An operating shaft 84 extends along the main axis from the latching body 74 into the electrically actuated portion 72, through the second fixed coil 82. The operating shaft 84 has a permanent magnet 86 located at an outer end thereof; that is, an end closest to the first fixed coil 80. The permanent magnet 86 is sized so as to be able to locate inside the first fixed coil 80 when the latching mechanism 70 is in an open configuration as shown in Figure 8, and to be able to locate inside the second fixed coil 82 when the latching mechanism 70 is in a closed configuration as shown in Figure 9.

[0044] It will be appreciated that the permanent magnet 86 may be replaced with a third coil of similar size, the coil being actuated by a DC current.

[0045] The operating shaft 84 is pivotally connected at an inner end thereof to a connecting rod 88. The connecting rod 88 is in turn fixed to a latching member 90, which is mounted about a pivot 92. The arrangement is such that movement of the permanent magnet 86 towards the second fixed coil 82 causes movement of the operating shaft 84 away from the first fixed coil 80, pushing the connecting rod 88 against the latching member 90, which rotates about the pivot 92 and results in a latch 94 protruding from the latching body 74. This is the closed configuration shown in Figure 9.

[0046] A spring 96 is attached to the latching member 90, and is biased to return the latch 94 within the body latching body 74 in the absence of a driving force. This is the open position shown in Figure 8.

[0047] The force to drive the latching member 90 between the open and closed configurations is provided by the passing of an electrical current through the first and second fixed coils 80, 82, generating an appropriate magnetic field to act on the permanent magnet 86.

[0048] Mechanical stops (not shown) are included to limit movement of the shaft in its axial direction forward or back. The mechanical stop associated with the first fixed coil 80 allows the permanent magnet 86 to penetrate about 30 - 40% of its axial length into the first fixed coil 80. This represents a 'failsafe' position of the latching mechanism 70, whereby in the absence of electrical excitation the spring 96 maintains the latching mechanism in its open configuration.

[0049] Similarly, the mechanical stop associated with the second fixed coil 82 allows the permanent magnet 86 to penetrate about 30 - 40% of its axial length into the second fixed coil 82. This represents a fully 'closed' position of latch 94.

[0050] The first and second fixed coils 80, 82 are electrically connected, and wired inversely, such that when the first fixed coil 80 is repelling the permanent magnet 86 the second fixed coil 82 is attracting it, and vice versa. The second fixed coil 82 has significantly more windings than the first fixed coil 80, thus providing it with a stronger magnetic force. This allows for optimisation of the maximal electrical power required. [0051 ] It is anticipated that the electrically actuated portion 72 may be filled with oil under pressure, to ensure against the ingress of seawater during operation.

[0052] Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.

Claims

1 . An electrically powered torque tool for use in a remote underwater environment, the torque tool including an electric motor, a gearing

arrangement, and a torque applying portion, the supply of electricity to the electric motor acting to drive the torque applying portion via the gearing arrangement, wherein the gearing arrangement has a gear ratio greater than 500 to 1 .

2. A control means for an electrically powered torque tool, the control means including a process controller which is arranged to communicate with a remotely located operator, the process controller being arranged to control the supply of electrical current to electric motor within the torque tool, wherein a feedback means is arranged to provide information to the process controller regarding the output of the torque tool.

3. A control means for an electrically powered torque tool as claimed in claim 2, wherein the feedback means includes at least one strain gauge.

4. A control means for an electrically powered torque tool as claimed in claim 2, wherein the feedback means includes at least two strain gauges.

5. A control means for an electrically powered torque tool as claimed in claim 3 or claim 4, wherein the strain gauge(s) is powered through a polarity changing bridge supply.

6. A latching mechanism associated with an electrically powered torque tool, the latching mechanism including an electromagnetic actuator, the electromagnetic actuator including a first fixed coil and second fixed coil, the first and second fixed coils being spaced along a main axis, the actuator including a driving shaft on which a magnetically responsive element is fixed, the driving shaft being arranged to pass through the second fixed coil, the driving shaft extending along the main axis, the driving shaft being

mechanically connected to a latch, wherein the supply of electrical current to the first and second fixed coils generates a magnetic field which acts on the magnetically responsive element in an axial direction causing the driving shaft to operate the latch.

7. A latching mechanism as claimed in claim 6, wherein the magnetically responsive element is a permanent magnet.

8. A latching mechanism as claimed in claim 6, wherein the magnetically responsive element is a third coil.

9. A latching mechanism as claimed in any one of claims 6 to 9, wherein the first and second coils are wired inversely, such that when current flows in one direction the first coil repels the magnetically responsive element and the second coil attracts the magnetically responsive element.

10. A latching mechanism as claimed in any one of claims 6 to 10, wherein the second coil contains more windings than the first coil, and thus provides a stronger magnetic field.