GB1503860A - Sand blasting machine with self-feeding apparatus - Google Patents

Abstract

1503860 Blasting SINVA SpA 18 June 1976 25337/76 Heading B3D A sand blasting machine comprises a cylindrical reservoir 1 for abrasive material having a lower portion connected by a duct 2 including a valve 3 to a line 4 leading to an ejector nozzle, the upper portion of the reservoir being integral with a tubular member 5 connected at its upper end to an annular member 6 accommodating a toroidal gasket 7, and an L-shaped duct 8 fitted within the tubular member and having a vertical portion housing a mushroom-shaped valve 9 which co-operates with the gasket. The member 6 is connected to the lower portion of a second cylindrical reservoir 10 which has a horizontal sieve 11 and is connected at its upper part to a second tubular member 12, the upper end of which is secured to a second annular member 16 accommodating a toroidal gasket 13, an L-shaped duct 14 being fitted in the member 12 and having a vertical portion housing a mushroom-shaped valve 15 for co-operation with the gasket 13. The member 16 is connected to a silo containing abrasive material. A compressed air duct 18 leads to a pilot valve 17 which controls the air supply to the line 4 leading to the nozzle, the duct 8, and a line 19 connected to an inlet valve 20, an automatic discharge valve 21, and a filter 22 leading to the duct 14 and a manual discharge valve 25. The pilot valve 17, inlet valve 20 and automatic discharge valve 21 are connected to a timer controlled pneumatic distributor 23, and the pilot valve is also controlled by a remote control on the nozzle connected to the valve by a pipe 24. When the pilot valve is opened, compressed air is supplied to the line 4, the duct 8 so as to close the valve 9 and pressurize the lower reservoir 1, and the duct 19, the timer controlled valve 20 being simultaneously operated to effect closure of the valve 15 and thus pressurize the upper reservoir 10. When the pressure in the upper reservoir reaches that in the lower, the valve 9 opens so that abrasive material passes from the upper to the lower reservoir. After a preset time, the valve 20 closes, valve 21 is opened to discharge air from duct 14 so that valve 15 opens to admit abrasive material to the upper reservoir until, after a further preset time, valve 20 re-opens and valves 21 and 15 close. The operation of the machine may be stopped at any time by actuation of the valve 17 by the remote control on the nozzle.