GB1411498A - Control system for the supply of a fluid material and valve means for such system - Google Patents

Abstract

1411498 Valves PRODEF ENGS Ltd 19 Oct 1973 [25 Aug 1973] 40359/73 Heading F2V A valve for use in a system controlling the supply of fluid material to a spraying device comprises a valve body 11 having an inlet port 12 for fluid material from a pump and an outlet port 13 formed in an upstanding seat 14. The latter co-operates with a spring loaded closure member which, as shown, is formed by a slidable piston 16 having a resilient insert 18 and a sealing 0-ring 17, but in a modification (Fig. 2, not shown) is formed by a diaphragm (25) backed up by a piston (28). Since the closure member 16 (or 25) has a greater surface area exposed to inlet pressure at port 12 than to outlet pressure at port 13 the valve opens when the inlet pressure exceeds a predetermined minimum to permit flow of fluid material through outlet port 13 to the spray gun or a mixing chamber associated therewith. An additional inlet 23 is provided for the supply of a solvent or air purge via non-return valve 24. The compression of biasing spring 20 can be adjusted by a screw 22 acting on plate 21. Supply pump operation may be initiated by an air signal from a trigger controlled pilot valve. When the trigger is released air is directed from the pilot valve to above piston 16 to assist the biasing action of spring 20. Simultaneously the pilot valve causes supply of purging fluid to inlet 23.