GB881129A - Reciprocating pumps - Google Patents

Abstract

881,129. Mud pumps. DOWTY ROTOL Ltd. June 7, 1960 [June 12, 1959], No. 20247/59. Class 102(1). [Also in Group XXIX] A reciprocating pump for liquids comprises cylinders 13, 14, pistons 15, 16 reciprocable in the cylinders by an actuating liquid, each assembly having a flexible diaphragm 62, Fig. 2 (not shown), separated from that face of the piston which is remote from the actuating liquid and which contains, with said face, a liquid filled chamber of substantially fixed volume, and a pumping chamber 64, Fig. 2 (not shown), on the other side of the diaphragm to receive the liquid to be pumped by the action of the piston / liquid/diaphragm assembly. A pilot valve spool 19 and main valve spool 24, both movable between two end positions, cause the pistons to reciprocate automatically under liquid pressure at the inlet 26, Fig. 3 (not shown), the spool 19 being moved by each piston at the inner end of its stroke to cause the spool 24 to move and thereby redirect pressure liquid to reverse the stroke of the piston. A safety vent valve 66, Fig. 2 (not shown), in the chamber between the piston 16 and diaphragm, is opened by a tension cord between the valve and the diaphragm when excess pressure is exerted on the latter due to internal leakage of liquid from outside the chamber.