GB952203A - Improvements in or relating to reciprocating pumps - Google Patents

Abstract

952,203. Reciprocating pumps. WEATHERHEAD CO. July 1, 1960 [July 6, 1959], No. 23169/60. Heading F1A. [Also in Division G3] The barrel 50 of a swash plate pump is non- rotatably mounted on a guide member 38 and is axially slidable thereon. Pump pistons 58 are reciprocated in one end of cylinder bores 52 by a swash plate 20 and control suction ports 57; reaction pistons 68 loaded by springs 75 are slidable in the other end of the bores 52 and engage members 69 carrying outlet valves 71 in the end plate 35. The barrel 50 is biased in the direction of the swash plate by the springs 75 and so by early closing of the ports 57 maximum delivery is achieved; the barrel is moved in the opposite direction to reduce delivery by the outlet pressure supplied to a chamber 84 under the control of a valve 90. The valve 90 has a cap 93 (Fig. 4) loaded by a spring 82 and a central member 105 which is adjustable by means of a screw plug 106 so that the position of the valve and the spring loading is adjustable. The valve controls an inlet passage 110 from the pressure outlet 7a, a passage 111 leading to the passage 88 connected to the chamber 84 and a discharge passage 114. The left end of the valve 90 is subjected to the pump outlet pressure and the right end to the pressure in the passage 88 and to the load of the spring 57. Maximum output may be controlled by a hand actuated stop for the barrel 50 (Fig. 10 not shown). The suction ports 57 of the various bores 52 may be axially displaced so that cylinders are progressively put out of action (Fig. 7 not shown). The pistons 68 may part from the members 69 to form auxiliary inlet valves.