Fluid abrasive jets for machining

Abstract

The apparatus comprises a storage vessel (19) for abrasive particles, a source of pressurised carrier fluid and a first conduit (11) to convey at least a major proportion of the incoming carrier fluid to a nozzle (16). A second conduit (9) connects the source of carrier fluid to an inlet of the storage vessel (19) and a third conduit (18) connects its outlet to the nozzle (16). A switching device (6) is selectively operable either to allow a minor proportion of incoming carrier fluid to flow through the second conduit (9) to the storage vessel (19), or to direct all of the carrier fluid through the first conduit (11). When a minor proportion of carrier fluid is directed through the second conduit (9), abrasive particles in carrier fluid are discharged from storage vessel (19) into the third conduit (18). When all of the carrier fluid is directed through the first conduit (11), fluid from the second conduit is entrained, thereby reversing fluid flow in the second (9) and third (18) conduits. The source of pressurised carrier fluid is preferably an intensifier plunger pump which has bearing surfaces (203) to guide a reciprocating cylinder (204). One end of the reciprocating cylinder (204) is closed and carries a plunger (201) and a connection (215) for driving fluid to enter the cylinder for the pump return stroke. The other end of the cylinder (204) has a piston (205) movable within a fixed cylinder (206) on which driving fluid acts during the pump delivery stroke.

Dependencies are inferred from the claim text.