Blast gun for flat jets containing solid abrasive particles

Claim 1

Sand blasting nozzle, particularly for the decontamination of radioactive parts by means of a jet formed from a mixture of water and abrasive particles, comprising a body (4), an inner duct (16), means (14, 114) for connecting a pipe for the supply of water under high pressure to said inner duct (16), which issues into a discharge nozzle (18,118) able to produce a single flat water jet within a vacuum chamber (6, 8, 9, 109), a supply pipe (29, 129) being provided on body (4) for supplying a mixture of air and abrasive particles to said vacuum chamber (6, 8, 9, 109), a discharge device (26, 126) provided on body (4), the water jet having an aperture angle (a) in the plane of the jet, the discharge device (26) having, in planes perpendicular to the flat jet, two small side walls (26b) on either side of the flat jet and, in planes approximately perpendicular to the plane of the flat jet, two large walls (26c), said discharge member (26) forming an integral part of the vacuum chamber, characterized in that the two small walls (26b) form between them a divergent angle, which is equal to the aperture angles (a) of the flat water jet and in that said large walls (26c) form a convergent angle between them.