Abrasive Feed System

Author:  Woodson, Jerry P.
Source:  US Patent 5,239,788
Doc ID:  1993033
Year of Publication:  1993
Abstract:  
In accordance with illustrative embodiments of the present invention, a hopper containing a sodium bicarbonate abrasive is pressurized with a dry gas such as nitrogen. The abrasive is fed into a transport line through which compressed air flows toward a nozzle, and pressures in the hopper and transport line are regulated so that the hopper pressure is greater than the transport line pressure by an amount that keeps the abrasive in the hopper very dry so that the same differential pressure causes a precisely metered amount of abrasive flow.