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A self-flushing fluid seal assembly is provided to prevent particle intrusion into the main seal around a slurry pump shaft. The assembly includes an annular tube concentrically disposed about the pump shaft and forming a chamber. The volume of the chamber is made variable by a plunger comprising an enlarged diameter portion of the pump shaft movable relative to the chamber during the power and return stroke of the pump. Flushing liquid is delivered to the chamber by means of a feed line extending through the shaft. A check valve provided in the feed line opens to allow the inward flow of flushing fluid from the feed line to the chamber as the chamber expands. Conversely, the check valve closes and a secondary shaft seal is provided to prevent the reverse flow of flushing fluid as the chamber contracts on the return stroke. Thus, during chamber contraction the flushing fluid is forced from the chamber through a passage around the tube and through the main seal to prevent particle intrusion into the seal during pumping, thereby reducing wear.


Board of Trustees of the University of KY, Lexington, Ky.

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