Patent GB-539264-A (GB)
Title: Improvements in or relating to hydraulic pumping apparatus and duplex hydraulic pumps
IPC: F04B9/115
Filed: 1939-11-29
Abstract: 539,264. Hydraulic pumping apparatus. STEVENS A. H. (Jackson, Co., B.). Nov. 29, 1939, No. 31071. [Class 102 (i)] [Also in Group XXIX] Hydraulic pumping apparatus providing a steady, pulseless discharge, particularly suitable for handling drilling mud for deep well drilling, comprises a pair of reciprocating piston pump units actuated by pressure liquid which is controlled by valve means associated with each unit, one or each valve means being actuated in pre-determined relation to the piston movement of the other unit. The two units are thereby actuated alternately, one pumping during the stroke-reversing period of the. other. The stroke of one unit is shorter than that of the other, and sufficient only to maintain continuous flow during reversal of the other unit, the pistons of the one unit, having completed their stroke, remaining at rest during the stroke of the other pistons. In the form shown, a central valve body A, carries on opposite sides a pair of elongated cylinders B, B<SP>1</SP> comprising concentric inner and outer cylinders 11, 12 and 11<SP>1</SP>, 12<SP>1</SP> defining annular channels 13, 13<SP>1</SP> communicating at their outer and inner ends respectively with the interiors of the cylinders 11, 11<SP>1</SP> and chambers 14, 14' which have suction and delivery valves 15, 15<SP>1</SP> and 16, 16<SP>1</SP> comunicating respectively with a common pump liquid suction header 17 and a common pump liquid discharge chamber 18. The cylinders 11, 11<SP>1</SP> contain pistons 21, 21<SP>1</SP> connected by a rod 22 passing through a partition 23 separating the inner ends of the cylinders. The body A also carries on opposite sides a pair of relatively short cylinders C, C<SP>1</SP> at right-angles to the cylinders B, B<SP>1</SP>. The former are'provided with inner liners 26, 26<SP>1</SP> to form channels 27, 27<SP>1</SP> which communicate respectively with channels 28, 281 having valves 29, 30 leading to the suction header 17 and the discharge chamber 18. The cylinders C, C<SP>1</SP> contain pistons 34, 34<SP>1</SP> connected by a rod 35. The upper portion of the body A further carries a pair of reversing valves R, R<SP>1</SP> parallel respectively to the cylinders C, C<SP>1</SP> and B, B<SP>1</SP>. The valve R comprises pair of connected shuttle valves 41, 41<SP>1</SP> which are reciprocated to admit motive liquid from an inlet 42 through one of two passages 43, 44 to one of the main cylinders 11, 11<SP>1</SP> and to exhaust spent motive liquid from the other main cylinder through the other passage to a discharge chamber 45. The valve R is provided with rods 61, 61<SP>1</SP> (not shown) linked to sleeves 65, 65<SP>1</SP> on the auxiliary piston rod 35 whereby it is reversed as the auxiliary pistons 34, 34<SP>1</SP> approach the end of their stroke. The valve R<SP>1</SP> is similarly constructed and operated to control the flow of motive liquid to and from the auxiliary cylinders C, C<SP>1</SP> by being reversed by the main pistons 21, 21<SP>1</SP>. In a modification, the auxiliary cylinders are parallel to the main cylinders, the valve mechanism including a pilot valve and a main valve carrying either one or two pairs of shuttle pistons which may co-operate with adjustable needle valves. Specification 530,050 is referred to.