GB1388587A - Electrically operated fluid pressure control valve - Google Patents

Abstract

1388587 Valves H€GGLUND & SÍNER AB 18 Aug 1972 [20 Aug 1971] 38721/72 Heading F2V A valve for maintaining a pressure at inlet port 6 proportional to the current supplied to electromagnet 2 has a closure member 11 carried by armature 10 which biases it towards seat 9 with a force dependent on the current, the armaturt extending with slight clearance through a combined bearing/seal 16 through which fluid from outlet chamber 12 can leak to serve as a lubricant. The armature is also displaceable by push-button 24. A check valve 19 in coupling 18 can be unseated, following removal of cap 21, by introduction of the stem of a pressure gauge. The effective diameter of seat 9 may be variable by providing a linearly movable or rotary plate having apertures of various diameter selectively alignable with the seat. Alternatively, nested liners in the passage through nozzle 8 may be selectively raised to define the inner diameter of the seat. The effects of hysteresis may be reduced by including an A.C. component to induce dither or by rotating the armature using an auxiliary motor or propeller, which latter may also produce a thrust on the armature. The closure member may alternatively have a male or female conical shape and may be connected to the armature with some lost-motion. In Fig. 23, an additional closure member 53 is included which seats at 58 upon de-energization of the magnet to prevent flow to port 56. In this case, the valve acts to maintain a pressure at port 56 proportional to the current supplied to the magnet. In either case, the constant of proportionality relating pressure and current may alternatively be varied by using closure members or seats of different diameter. The nozzle 8 may be radially constrictable, e.g. by means, e.g. a screw to adjust the constant of proportionality.