GB1136887A - Sucker rod compensator for subsurface well pumps - Google Patents

Abstract

1,136,887. Reciprocating pumps. BAKER OIL TOOLS Inc. March 31, 1967 [April 29, 1966], No. 14888/67. Heading F1A. A device for maintaining a full stroke of the bucket piston of a deep well pump, Fig. 3a (not shown), by compensating for changes in the lengths of the sucker rod and tubing strings due to temperature changes and the like, comprises a cylinder member 35 secured to the sucker rod 28 and a piston 68 secured to the pump operating rod 29. During the upward stroke of the bucket, liquid in chamber 47 beneath piston 68 is pressurized, and a small quantity passes through a restriction 51 into chamber 52, and then through passages 58 and 59 into reservoir 60 closed by a free piston 61 subjected to the pressure in wall tubing A. The slight flow of liquid through restriction 51 during each upstroke causes an effective lengthening of the sucker rod string until the bucket bottoms against an abutment in the pump barrel at the end of its downward stroke. When bottoming occurs, the continued downward movement of the sucker rod string reduces the pressure in chamber 47 sufficiently to open a spring-loaded valve 71, liquid then passing from chamber 52 into chamber 47 while cylinder 35 moves downwardly relative to piston 68. The device automatically adjusts the sucker rod string length so that the bucket lightly taps the bottom of the barrel at the end of each downward stroke.