Rod seal cartridge for progressing cavity artificial lift pumps

Abstract

A seal cartridge particularly suitable for artificial lift pump rod sealing and for other applications where a rotating drive shaft penetrates a pressurized reservoir which is filled with abrasive-laden liquids, mixtures or slurries. The cartridge exploits a pressure responsive area of a wear sleeve to eliminate internal bearing running clearance in order to achieve a true-running rubbing surface which is conducive to the longevity of the compression-type rotary seals which are employed. A cartridge mounting mechanism is incorporated which overcomes stuffing box to rod misalignment, and is readily adaptable to pumps made by different manufacturers. The cartridge provides for leakage annunciation in the event of failure of a redundant rotary seal, and also provides for automatic pump shut down if a primary rotary seals fails. A redundant sealing arrangement between the wear sleeve and rod is incorporated which is relatively immune to installation damage, and to damage resulting from rod run out and vibration. By incorporation of a split drive clamp, the cartridge is able to exploit space within the pump yoke which is ordinarily reserved for the occasional use of rod clamps. The cartridge also incorporates an active cooling system which dissipates heat generated by the seals and bearings.