Sub-sea pipe cleaning apparatus and method

Abstract

Apparatus and method for cleaning the exterior surface of a pipe such as a pipe located in a sub-sea location having a coating of concrete or the like thereabout. The apparatus includes a generally longitudinal frame which supports a carriage for longitudinal traverse therealong. The carriage supports a high-pressure fluid nozzle which is arranged to direct the discharge thereof against the pipe coating which is to be removed. The carriage is arranged for longitudinal traverse along the frame, to thereby direct a high-pressure fluid stream into contact with the surface of the pipe. The frame is also arranged for rotation about the pipe, whereby a section of the pipe can be cleaned about its full circumference by a number of generally longitudinal runs along the pipe section being cleaned. The carriage may also support a wire cutter for cutting any re-enforcing wire after the concrete has been dislodged by the fluid nozzle. A pipe-cutter may also be attached to the apparatus for making a circumferential cut or cuts to remove a damaged section of pipe. The apparatus may be raised and lowered in a body of water to and from the cutting or cleaning position by a buoyancy tank attached thereto which is arranged to either raise or lower in a body of water in response to changes in the buoyancy factor of the tank, which may be controlled from the surface, for example.