Spiral groove seal

Claim 1

Apparatus for forming a seal about a rotatable shaft extending into a container of liquid sodium comprising a pair of juxtaposed members extending about said shaft adjacent said liquid, one of said members comprising a seat mounted on said shaft for rotation therewith, said seat being of a material selected from the group consisting of titanium carbide and molybdenum, a copper tubular member mounted for reciprocable movement along said shaft, mating surfaces on said members, one edge of each of said surfaces being in contact with said liquid sodium and the opposite edge being exposed to ambient pressure, biasing means for moving said tubular member toward said seat thereby moving said surfaces into sealing engagement when said shaft is stationary, and spiral grooves on at least one of said mating surfaces immediately adjacent said liquid, said spiral grooves being separated by lands substantially coplanar with said mating surface whereby rotation of the said shaft pumps a portion of said adjacent contained liquid sodium between said lands to generate a hydraulic lifting force thereby separating said members in opposition to said biasing means while inhibiting leakage.