Abstract: A noise suppressed blasting system comprising: a source of blasting gas in a predetermined pressure range with abrasive particles entrained therein; a nozzle including a nozzle inlet for connection to the source of blasting gas, a nozzle outlet for emission of the blasting gas, a nozzle conduit from the nozzle inlet to the nozzle outlet including a throat therebetween with a ratio of area of the nozzle outlet to area of the throat selected to emit the blasting gas from the nozzle outlet to produce a supersonic jet; a silencer connectable to the nozzle, to receive the supersonic jet exiting the nozzle, the silencer comprising a body with a silencer conduit therethrough, the body being of sufficient length and diameter to cause a flow condition of the jet received from the nozzle outlet to be modified such that 1½ shock cells are created in a jet inside the silencer, no shock cells are created in the jet outside the silencer and a jet exits the silencer in the form of a core jet with an established turbul

Abstract: A blast nozzle thrust reduction blasting system comprising: a source of blasting gas in a predetermined pressure range with abrasive particles entrained therein; a nozzle including a nozzle inlet for connection to the source of blasting gas, a nozzle outlet for emission of the blasting gas, a nozzle conduit from the nozzle inlet to the nozzle outlet including a throat therebetween with a ratio of area of the nozzle outlet to area of the throat selected to emit the blasting gas from the nozzle outlet to produce a supersonic jet; a thrust reducer connectable to the nozzle, to receive the supersonic jet exiting the nozzle, the thrust reducer comprising a body with a thrust reducer conduit therethrough, the body being of sufficient length and diameter to cause a flow condition of the jet received from the nozzle outlet to be modified such that a zone of sub-atmospheric pressure forms adjacent a face of the outlet of the nozzle whereby a pressure differential arises between the zone of sub-atmospheric press

Abstract: Detailed are valve assemblies principally for use as part of in-floor cleaning systems for swimming pools. The assemblies may use mechanisms for converting continuous rotation into discontinuous rotation, changing the timing of water distribution to different outlet of the assemblies. One such mechanism includes both an impeller, whose blades are rotated continuously by impingement of pressurized water, and a Geneva drive, whose driven wheel is rotated discontinuously by one or more associated drive wheels.

Abstract: Detailed are valve assemblies principally for use as part of in-floor cleaning systems for swimming pools. The assemblies may use mechanisms for converting continuous rotation into discontinuous rotation, changing the timing of water distribution to different outlet of the assemblies. One such mechanism includes both an impeller, whose blades are rotated continuously by impingement of pressurized water, and a Geneva drive, whose driven wheel is rotated discontinuously by one or more associated drive wheels.