Patent ID: 7337991

Claim:
An accessory adapted to be mounted on the end of an outlet conduit ( 4 ) of an air blast device ( 1 ), said accessory comprising a tube having an axial passage, said tube adapted to be mounted coaxially with an axis of the outlet conduit, said tube having a cross-sectional area along its axis that decreases in a direction (F) in which a predetermined finite amount of air is adapted to suddenly be discharged from the outlet conduit of the device ( 1 ), said tube then increasing in cross-sectional area along its axis—in the direction (F), thus forming a convergent segment (A) having an inlet cross-section area (E) and a throat area of smallest cross section (D) followed by a single-angled divergent segment (B) having an outlet cross-section area (S) adapted to produce an instantaneous impact force external to the outlet cross-section (S) from the sudden discharge of the predetermined finite amount air.