Sandblaster

Claim 1

A sandblasting apparatus comprising an upright container for containing abrasive grit under pressure and having a discharge opening at its bottom, a manually-operable grit flow-regulating valve communicating with said discharge opening, an air and sand mixing chamber including a compressed air inlet nipple, a grit inlet nipple, an outlet nipple and a fourth nipple forming a unitary unit and adapted to be mounted under said upright container with said grit inlet nipple disposed upright and communicating with said grit flow-regulating valve, aid air inlet nipple and outlet nipple axially aligned and making a substantially right angle with said grit inlet nipple, said fourth nipple making an acute angle with said air inlet nipple, all of said nipples intersecting and defining a cavity at their intersection, said air inlet nipple provided with means for connection to a supply of air under pressure, a sandblasting hose, of elastomeric material, having one end portion inserted into and detachably secured to said outlet nipple and carrying a nozzle at its other end portion, said hose having a bore, the inner end of said hose exposed within said cavity, a double-acting pressurized air-operated cylinder and piston unit removably mounted on, and carried by, the outer end of said fourth nipple, a piston rod fixed to the piston of said unit and axially extending through said fourth nipple, a ball fixed to the outer end of said piston rod and of larger diameter than that of said bore, said ball movable by said cylinder and piston unit between a retracted position confined within said fourth nipple and shielded from grit flowing through said grit inlet nipple, and an advanced position abutting said hose inner end and sealing said bore, and remote control means operable at said nozzle for operating said cylinder and piston unit.