Abstract

Sand blast apparatus is disclosed, which includes a housing with a water inlet nozzle positioned in its rear wall for producing a gradually diverging water jet in the housing, a sand inlet conduit extending obliquely downwardly into said housing, and a discharge nozzle having tapered and cylindrical water discharge passage sections in axial alignment with the water jet and extending from the front wall of the housing. Water under pressure is delivered to the inlet nozzle through a conduit extending back from the housing and having a downwardly extending pistol grip handle and water control valve at its rear end. The apparatus is provided with an upwardly extending handle for use with the pistol grip handle in holding the apparatus in a correct operating position. A vacuum is produced in the housing by venturi action, extending through a sand supply conduit which includes two air inlets, one at a sand supply and another near the water control valve, for drawing two separate air streams into the conduit to fluidize the sand and provide accurate regulation of the sand flow rate.