Abrasive Blast Cleaning Nozzle

Author:  Gary S. Settles
Source:  US Patent 5,975,996
Doc ID:  1999071
Year of Publication:  1999
Abstract:  
A nozzle for an abrasive blast cleaning apparatus consisting of a short, relatively rapidly converging inlet section, a constant-area throat, a rapidly diverging first diverging section, and a long second diverging section that diverges less rapidly than the first diverging section. The inlet section quickly accelerates the abrasive particles after entering the nozzle, while the first diverging section rapidly brings the relative velocity of the air stream and the abrasive particles to about Mach 1.4. The second diverging section helps to maintain the relative Mach number while the abrasive particles continue to accelerate. This makes abrasive blast cleaning more efficient, particularly because the kinetic energy of the abrasive particles emerging from the nozzle is significantly increased.