WO1985001904A1

WO1985001904A1 - Apparatus for cutting materials underwater

Info

Publication number: WO1985001904A1
Application number: PCT/AU1984/000216
Authority: WO
Inventors: Nicholas Fielder
Original assignee: Subsea International Inc.
Priority date: 1983-10-25
Filing date: 1984-10-25
Publication date: 1985-05-09
Also published as: EP0160052A1

Abstract

A remote control vessel (11) is fitted with a detachable work platform (12) having a manipulator arm (13) mounted thereon. The arm (13) carries a blow torch (14) to which is fed a burning cable (15) from a drum (22) carried by the platform (12). Sensors are provided for monitoring the flame of the blow torch (14) and the flow of oxygen and supplying the information to control means incorporating a computer located on a surface vessel.

Description

"Apparatus for Cutting Materials Underwater"

THIS INVENTION relates to apparatus for cutting materials underwater using remote operated vehicles (ROV's).

With underwater operations such as those associated with offshore drilling platforms it is often necessary to per¬ form cutting operations underwater using oxygen lances such as kerie cable or flexible burning cable. This is a difficult and often dangerous operation for divers to perform as it is difficult for them to remain in the de¬ sired position due to the ocean currents.

The object of the invention is to provide apparatus for cutting materials underwater which is remote controlled and substantially automatic.

In one form the invention resides in apparatus for cutting materials underwater comprising a remote controlled self propelled submersible vehicle, a work platform detachably mounted on the vehicle, a manipulator arm mounted on the work platform, means for feeding a kerie cable or a flexi¬ ble burning cable to a blow torch carried by the manipula¬ tor arm and control means responsive to the flame produced by the burning kerie cable or flexible burning cable.

The control means may include one or more fibre optics units mounted on the manipulator arm for monitoring the flame and coupled to means for feeding the kerie cable or flexible burning cable to the manipulator arm and/or the oxygen supply to the kerie cable or flexible burning cable.

The invention will be better understood by reference to the following description of one specific embodiment shown in the accompanying drawings wherein:-

OMPI Fig. 1 is an exploded diagrammatic perspective repre¬ sentation of the apparatus;

Fig. 2 is a plan view of the unit separated from the self propelled submersible vehicle; Fig. 3 is a side elevation corresponding to Fig. 2; Fig. 4 is a plan view of the top of the base plate of the kerie cable drive unit; Fig. 5 is a section on line 5-5 of Fig. 4; Fig. 6 is a plan vew of the underside of the base plate of the kerie cable drive unit; Fig. 7 is a section on line 7-7 of Fig. 6; Fig. 8 is an elevation of the cutting torch assembly; Fig. 9 is a section on line 9-9 of Fig. 8; Fig. 10 is an end view of the cutting torch assembly; Fig. 11 is a block diagrammatic representation of the control system.

As shown in Fig. 1 the remote controlled self propelled submersible vehicle 11 is of known construction and in accordance with the invention is provided on the underside with a detachable work platform 12 on the forward end of which is mounted a manipulator arm 13 also of known con¬ figuration. The arm is adapted to grip a torch 14 through which a kerie cable or a flexible burning cable 15 is fed from a drum 16 mounted on the platform. The flow of oxygen to the burning cable is controlled through valves 15a (Fig. 1). The movement of the kerie cable is control¬ led by a control unit. The control unit is supplied with information from a number of sensing devices. Among these are a number of optic fibre units which monitor the flame generated by the torch during the cutting operation. Also sensors to sense the flow of oxygen through the kerie cable or flexible burning cable, and sensors to sense the operation of the suction grips normally used to hold the vehicle in position also feed information to the control unit. If the suction pads loose suction, or if there is

O PI i ^• *• W3PO > blow back from the torch or if the torch moves off the track/determined as hereinafter described the valves shut off the flow of oxygen.

As shown in Fig. 1 of the drawings the work platform is constructed of tubular metal elements in the form of a skid mounting frame and is provided with a forwardly projecting portion 17 on which the base 18 of the manipu¬ lator arm 13 is mounted. The work platform is provided with a series of upwardly projecting posts 19 each fitted at the upper end with arcuate saddle members adapted to engage the lowermost portion 21 of the self propelled vehicle 11.

As will be best seen from Figs. 2 and 3 of the drawings a drum 22 on which the kerie cable is wound is mounted on the work platform which carries an electronic junctions box 23, a kerie cable transport unit or drive box 24, an electronics dry box 25, a hydraulics valve box 26, and a transformer box 27 and suction pump 28. A control box 29 for controlling the manipulator arm is mounted on the R.O.V.

The kerie cable transport unit or drive box 24 is shown in more detail in Figs. 4, 5, 6 and 7 of the drawings. It comprises a base plate 30 on which is mouned a gear box 31 the input shaft of which is provided with a driving wheel 32. The output of the gear box is coupled through a gear wheel 33 which drives gear wheels 34, 35, 36 and 37 which are coupled to grooved driving wheels 38. The gear wheels 36 and 37 are mounted on plates 39 and 40 to which is fitted a tension spring 41. The kerie cable is gripped by the grooved driving wheels 38 and is held in place by guides 42, 43 and 44. The kerie cable is fed through the manipulator arm 13 following the path outlined in Fig. 1 to a blow or cutting torch the constructon of which is shown in Figs. 8, 9 and 10 of the drawings. The main body 51 of the torch is positioned so that its outlet end is located between a pair of trammel wheels 52 located at the front of the unit. The kerie cable is fed into the rear of the main body through guide 53.

In operation the unit is launched in the usual manner and guided to the working position using the TV monitor provided on the R.O.V. The blow torch is ignited and the cutting operation commenced, the control of the operation being effected through the various sensors provided on the work platform. If desired suction cups (not shown) may be used to hold the unit in position adjacent the surface to be cut.

If desired the unit may be manipulated to move along the line of the cut with appropriate information being fed back to the surface and stored in a computor. The actual cutting can then be carried out with the unit operating in accordance with the information supplied by the computor.

Claims

THE CLAIMS defining the invention are as follows:-

1. Apparatus for cutting materials underwater comprising a remote controlled self propelled submersible vehicle, a work platform detachably mounted on the vehicle, a manipu¬ lator arm mounted on the work platform, means for feeding a kerie cable or a flexible burning cable to a blow torch carried by the manipulator arm and control means respon¬ sive to the flame produced by the burning kerie cable or flexible burning cable.

2. Apparatus as claimed in claim 1 wherein one or more fibre optics are mounted adjacent the flame produced by the kerie cable and are coupled to the control means.

3. Apparatus as claimed in claim 1 wherein sensors to sense the flow of oxygen through the kerie cable or the flexible burning cable and sensors to sense the operation of ^* suction grips to hold the unit stationary in the desired position are connected to the control unit. ^"*

4. Apparatus for cutting materials underwater comprising a remote controlled self propelled submersible vehicle, a work platform detachably mounted on the vehicle. A manipulator arm mounted on the work platform, means for feeding a kerie cable or flexible burning cable to a blow torch carried by the manipulator arm, means for holding the unit to the structure which has to be cut, sensors for monitoring the flame of the blow torch, the flow of oxygen to the torch and the holding means and control means mounted on a surface vessel for controlling the operation of vehicle.

5. Apparatus for cutting materials underwater substan¬ tially as herein described and as shown in the accompany¬ ing drawings.

OMPI_