Patent ID: 8251773

Claim:
A control system for a high pressure cutting arrangement, the cutting arrangement comprising a liquid stream and a slurry stream, the slurry comprising abrasive particles suspended in a fluid, the liquid stream and the slurry stream being supplied under pressure to a cutting tool, such that at least a portion of the supplied pressure is converted to kinetic energy in the cutting tool to produce a combined liquid and abrasive stream at high velocity, wherein the cutting tool includes a combining chamber into which both the liquid and slurry streams are introduced, the pressure in an entry region of the combining chamber being determined by the pressure of the liquid stream, the control system acting to actuate or prevent flow of slurry in the slurry stream by activation or de-activation of an energising means up-stream of the chamber, and whereby pressure in the slurry stream is substantially equal to the pressure in the entry region of the combining chamber whether or not slurry is flowing.