DRIVE FOR WELL PUMPING UNIT (VERSIONS) Russian patent published in 1999 - IPC

FIELD: lifting liquids from deep depths; driving two sucker-rod well pumps. SUBSTANCE: drive includes two hydraulic cylinders 1 and 2 with rod chambers 3 and 3' and rodless chambers 4 and 4', pneumohydraulic accumulator 14, pump 7 and hydraulic distributor 8 interconnected together. Drive is provided with second pneumohydraulic accumulator 14'; each pneumohydraulic accumulator 14 and 14' is made in form of tandem cylinder with rod 16 and 16' having pistons 18, 19, 18', 19' at the ends, thus forming two chambers 20, 21 and 20', 21'. One rod chamber 20 and 20' is connected with rod chamber 3 and 3' of respective hydraulic cylinder 1 and 2. According to first version, second rod chamber 21 and 21' of pneumohydraulic accumulator 14 and 14' are connected with pump 7 and with return pipe line 25; rodless chambers 4 and 4' of hydraulic cylinders 1 and 2 are interconnected. According to second version, rod chambers 21 and 21' of pneumohydraulic accumulator 14 and 14' are interconnected and rodless chambers 4 and 4' of hydraulic cylinders 1 and 2 are connected via hydraulic distributor 8 with pump 7 and return pipe line 25. During operation of drive, required similar and different pressure is built up in rod chambers 4 and 4' of hydraulic cylinders 1 and 2. High-pressure pipe lines 22 and 22' connecting hydraulic cylinders 1 and 2 with pneumohydraulic accumulator 14 and 14' are located in above-well equipment of each well. EFFECT: enhanced reliability and safety; ease in use; enhanced economical efficiency. 8 cl, 4 dwg