GB1058400A - Improvements in and relating to fluid flow control devices - Google Patents

Abstract

1,058,400. Valves. AUTOMOTIVE PRODUCTS CO. Ltd. Dec. 22, 1965 [Oct. 13, 1964], No. 41777/64. Heading F2V. [Also in Division G3] The connection of outlet ports 6, 7 to an inlet port 5 and return ports 8, 9 is effected by a piston valve 27 slidable in a ported sleeve 10 and an adjustable rod 52 with a central biconical land 61; the position of the valve 27 is determined by a nozzle flapper arrangement 45-47 influenced by an electrical input signal. Fluid entering the inlet 5 flows into an external groove 15 in the sleeve 10 from where it can enter outlet port 6 or 7 depending upon the movement of valve 27. The fluid also enters the annular grooves 31, 32 between valve lands 28-30 and flows via radial drillings 33, 34 where it is divided by the rod land 61 before admission to annular chambers 59, 60 between the rod 52 and valve 27; the fluid leaves each chamber 59, 60 by opposite-handed helical grooves 38, 39 to enter chambers 13, 14 connected to nozzles 45, 46, respectively. Movement of the flapper 47 from a neutral position increases the pressure in one chamber and decreases it in the opposite chamber, whereupon the valve 27 is displaced and the flow into each chamber is thereby altered by this displacement relative to the land 61 until the valve 27 reaches a position of equilibrium. The fluid discharge from the helical grooves 38, 39 causes rotation of the valve 27. In a modification, the rod 52 is dispensed with and the valve bore is intersected by a pair of inlets. The helical grooves are associated with chambers at the ends of the valve bore, whereby the effective length of the groove moving into the adjacent chamber is reduced to provide pressure compensation across the valve. The same effect may be realised by forming ports in the valve through which fluid is supplied to the grooves as shown in Fig. 1.