Method and apparatus for shot blasting materials

A method of shot blast cleaning a workpiece comprising the steps of:

• applying a composite stream of carrier liquid and particulate abrasive material under high velocity to said workpiece contained within a blast cabinet for cleaning said workpiece by an abrasive throwing wheel having a vaned impeller rotatably mounted within a casing for receiving an abrasive slurry at a relatively low velocity and discharging said slurry at a relatively high velocity out through said open side, supplying the abrasive slurry to the vaned impeller radially onto the impeller at the centre thereof from a supply spout, said supply spout having a first conduit feed section disposed parallel to the impeller, a second conduit section perpendicular to the first conduit feed section and co-axial with the impeller terminating in a pair of spaced-apart radially directed outlets perpendicular to the second conduit section, whereby abrasive particles in the slurry are deflected by centrifugal force into an upstream outlet and the liquid deflected into a downstream outlet onto the impeller for discharge therefrom;
• transporting spent composite stream after cleaning to an abrasive material separator for separating said abrasive material from the carrier liquid and for removing undersized abrasive material to produce sized abrasive material;
• storing said sized abrasive material in a storage feed tank in communication with a shot mixing valve;
• cleaning said carrier liquid for reuse of said carrier liquid;
• and
• pumping the cleaned carrier liquid under pressure through the shot mixing valve for inducing abrasive material into said liquid and applying said carrier liquid and said abrasive material as separate streams concurrently from the upstream outlet and from the downstream outlet of the throwing wheel onto the workpiece contained within said blast cabinet in a substantially overlapping blast pattern.