The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 15, 1987
Filed:
Oct. 09, 1985
William W Dollison, Dallas, TX (US);
Otis Engineering Corporation, Dallas, TX (US);
Abstract
A hydraulic well pump for operating a pump sucker rod string including a hydraulic cylinder assembly for raising and lowering the sucker rod string and a fluid counterbalancing system for offsetting the combined weight of the reciprocating service equipment, the fluid column above the pump plunger, and the sucker rod string. One counterbalancing embodiment includes an air supported piston on the movable cylinder exposed to an air chamber below the air piston functioning independently of the hydraulic and power and logic system of the pump. Another counterbalancing system embodiment uses a hydraulic fluid accumulator connected into the system fluid power and logic for supercharging the hydraulic power pumps during the lift stroke and providing opposing force during the downstroke. Also disclosed are: a stroke length multiplier apparatus including a multi-layered strip metal tension member; a pump stroke sensor and control for adjusting stroke end limits and lengths; and a fluid logic system for controlling stroke acceleration and deceleration.