Pipe material removal apparatus and method

An apparatus for removing material lining the inside surface of a cylindrical structure, the apparatus comprising:

• a support for supporting said cylindrical structure in a horizontal orientation;
• an elongate boom for being inserted into said cylindrical structure;
• a nozzle assembly connected to said elongate boom, the nozzle assembly comprising one or more nozzles wherein each nozzle is spaced from said material to deliver a jet of water under pressure to said material;
• a conduit in fluid communication with the nozzle assembly for delivering a flow of water to each nozzle under sufficient pressure to cut said material adjacent said each nozzle;
• and
• a rotation mechanism cooperating with the support to passively enable said cylindrical structure to be rotated while supported by the support or to actively impart rotation to said cylindrical structure while supported by the support, wherein the rotation of said cylindrical structure is about a central longitudinal axis of said cylindrical structure;
• and wherein said nozzle assembly comprises:
• a first set of nozzles directed to impinge on said inside surface at a first location and a first high pressure conduit in fluid communication with the first set of nozzles;
• a second set of nozzles spaced longitudinally in relation to said elongate boom from said first set of nozzles and directed to impinge on said inside surface at a position spaced from said first location and a second high pressure conduit in fluid communication with the second set of nozzles;
• and
• wherein the first high pressure conduit is connected to a first source of high pressure water and the second high pressure conduit is connected to a second source of high pressure water such that the first set of nozzles may be operated at a different pressure than the second set of nozzles.