Patent ID: 7063593

Claim:
A process for treating the boundary walls of an interior chamber formed in a workpiece, comprising the steps of: providing a workpiece having a plurality of interior chambers which are sidewardly spaced apart and transversely interiorly interconnected, and first and second aligned access openings communicating with opposite ends of each respective interior chamber; providing pluralities of first and second nozzle members positioned so that each of said first nozzle members is disposed in opposed relationship to a corresponding one of said second nozzle members; simultaneously inserting all of said first nozzle members into the workpiece and also simultaneously inserting all of the second nozzle members into the workpiece so that each of the opposed pairs of first and second nozzle members is positioned within a respective one of the interior chambers and discharge openings of the opposed first and second nozzle members are positioned closely adjacent and directly opposed to one another; simultaneously supplying substantially equal streams of pressurized blasting media, as defined by a pressurized carrier fluid having solid abrasive particles entrained therein, to the discharge openings of all of the first and second nozzle members; simultaneously discharging substantially equal and opposed high-velocity streams of blasting media from said discharge openings so that the discharged streams, almost immediately after discharge, directly impact one another to cause the blasting media to be deflected radially outwardly in a surrounding annular pattern for high energy impact with the boundary wall of the respective interior chamber; and simultaneously moving the nozzle members, while maintaining them in generally fixed relationship to one another, along the respective interior chamber so that the blasting media as deflected radially outwardly into the annular pattern progressively treats the boundary wall of the respective interior chamber.