Abstract: Apparatus for treating a workpiece has first and second regions at least partially enclosed by a casing and in communication via a passage, and support means for a carrier holding the workpiece in the first region for treatment. Pressure difference between the regions forces the workpiece toward the carrier and guides a flow of media from the first to the second region through the passage, at least partly, to create said pressure difference. Method for treating at least one workpiece holds the workpiece by forcing it toward the carrier with a created pressure difference between two regions. Holding also guides a flow of media from the first region to the second region through the passage in order to, at least partly, create said pressure difference. The treatment may comprise blasting, rinsing or drying. The workpiece may comprise cutting inserts, electronic components, small sized machined or formed components or parts.

Abstract: Wet blast apparatus 1 is provided with a sump 2 for collecting liquid and abrasive particles after use, a duct 40 for conducting the collected material to a three-stage weir system 4 whereby the particles are separated out. The apparatus is further provided with a fluid flow control valve 3 operable to control the flow of collected material to the separating system 4. An adjustable timer 25 is provided for delaying the flow of collected material to the separating system 4. The control valve 3 comprises a valve member 6 cooperable with a valve seat 7, the valve member 6 being expansible whereby it can be enlarged so as to coact with the valve seat 7. The valve member 6 is of hollow, inflatable form, comprising a flexible membrane 10, clamped between a plate 11 and a ring 12. An actuating chamber 20 is defined by the plate 11 and the membrane 10. Pressurized air is admitted to, and exhausted from, the chamber 20 by way of a control valve 21 disposed in an air line 22.