GB937951A - Control system for sandblasting equipment - Google Patents

Abstract

937,951. Sandblasting. A. J. CLEARY, and R. J. STEIL. May 4, 1960, No. 15823/60. Class 60. A control system for sandblasting equipment comprising a main feed line connected to a source of high pressure fluid, and a sand tank for feeding sand into said main feed line between a normally closed main valve located in said main feed line and the delivery end of said main feed line, includes a fluid pressure actuator for said main valve, a control line connected at one end thereof to said main feed line on the highpressure side of said main valve, a manually operable valve at the other end of said control line adjacent said delivery end of said main feed line, and a conduit connected to and establishing fluid communication between said fluid pressure actuator of said main valve and said control line intermediate the ends thereof, and a conduit connected at one end to said main feed line and connected at its other end to said sand tank for applying fluid pressure to said sand tank, the manually operable valve when in closed position allowing the fluid pressure in the control line to be communicated to said fluid pressure actuator for said main valve to cause said main valve to move to open position. A source of high pressure air is connected to an inlet pipe 10 connected to a spring-closed main valve 11 connected by a pipe 13 to a flexible main feed line 13a terminating in a nozzle 3. A sand tank 15 has a sand outlet pipe connected through a spring-closed sand control valve 20 to the main feed line 13a. The main valve 11 is also connected by a pipe 14 to the upper portion of the tank 15; a pipe 16 from the tank 15 is connected to a spring-opened exhaust valve. A control line 22 is connected to the inlet pipe 10, the connection including a plug with a restricted orifice therethrough. The control line 22 is connected to a piston type operator 12 for the main valve 11, to a diaphragm chamber 27 for the sand control valve 20 and to a piston type operator 18 for the exhaust valve 17; the control line 22 is connected to a flexible line 28 terminating in a normally open valve 29 having a spring pressed button 30. The flexible line 28 lies generally parallel to the main feed line 13a and may be taped or otherwise fixed thereto with the valve 29 adjacent the nozzle 3. To avoid inadvertent operation, a bleed valve 31 connected to the control line 22 is normally left open. To operate the equipment, the bleed valve 31 is closed so that when the operator closes the valve 29 the pressure rise in the control line 22 opens the main valve 11, opens the sand control valve 20 and closes the exhaust valve 17. In a modification, Fig. 2, the main valve 11<SP>1</SP> and sand control valve 20<SP>1</SP> are operated as above, but air is supplied to the tank 15<SP>1</SP> from upstream of the main valve 11<SP>1</SP>, and the pipe 16<SP>1</SP> from the tank has a manually operated exhaust valve 17<SP>1</SP>.