GB567853A - Improvements in hand-operated pumps - Google Patents

Abstract

567,853. Reciprocating pumps. PYRENE CO., Ltd., and ZIESCHANG, R. July 1, 1943, No. 10703. [Class 102 (i)] In a hand-operated doubleacting pump of the kind in which a piston 20 reciprocates in a cylinder 2 within a container 1 for the liquid, and in which the cylinder is provided with non-return inlet valves 13, 14 at both ends so that the pump can be used either way up, the piston is formed with one or more axial passages 28-30 and is fitted with a clack valve 22 on the side of the piston nearer the operating handle 9, whereby, at each stroke, a part of the liquid in front of the piston is expelled and the remainder passes through the passages to the rear of the piston. Preferably, the valve 22 is rigidly connected to a second clack valve 21 on the other side of the piston by means of rods 23 making a close sliding fit in axial passages in the piston. The latter is fitted with a sealing ring 27 of the kind described in Specification 494,397. The piston has end recesses 31, 32 co-operating with ports 33, 34 in the wall of the hollow pistonrod 6, and the passages 28-30 open into an annular groove 35. The valve 22 has a clearance 37 around a stop sleeve 36 on the piston-rod, and two axial passages 38 out of register with the passages 28-30, but in register with the groove 35. The valve 21, has a clearance 39 around the closed end 5 of the piston-rod, and two axial passages 40 out of register with the passages 28-30. It also has an annular projection 43 and a projection 42 aligned with the passage 30 so as to reduce the flow through the assembly, and therefore increase the amount of liquid expelled, during the inward stroke, in comparison with that during the outward stroke.