GB631597A - Improvements in or relating to rotary valves for pumps - Google Patents

Abstract

631,597. Rotary cylindrical valves. VARLEY PUMPS & ENGINEERING, Ltd., and VARLEY, C. H. Nov. 13, 1946, No. 33685. [Class 135] [Also in Group XXVIII] A rotary valve for a multi-cylinder highhigh-pressure liquid supply pump in which the pistons are reciprocated by a swashplate is so timed in relation to the piston movements that it lags up to 20 degrees behind its correct position, thus silencing the pump. The valve, which is balanced hydraulically, is rotated through an Oldham coupling 7, Fig. 1, by the swashplate shaft 6 and comprises a core 5, Fig. 7, having a suction cavity 11 and delivery cavity 12, fixed. within a sleeve 8, Fig. 8, having two pairs of ports a, c<SP>1</SP>, and b, c, from the delivery and suction cavities respectively. The valve rotates within a fixed liner 9, Fig. 6, having three sets of ports, one pair A acting in turn as delivery ports, a pair B acting in turn as suction ports, and three pump cylinder ports C. A pair of peripheral grooves d on either side of the port c<SP>1</SP> connect with the suction cavity, while a pair d<SP>1</SP> on either side of the port c connect with the delivery cavity via holes 14 and passages 15, 16 so that the valve will be balanced with respect to the pressure in the ports c, c<SP>1</SP>. Opposite, of the same length as, and having a combined area equal to each pump cylinder port C, are two crescent-shaped grooves e on the inner surface of the liner 9 which register in turn with the peripheral grooves when the opposite pump port is under pressure, so that the valve will be balanced with respect to the pressure in the pump ports.