Abstract: An impeller pump including a housing defining a seal cavity having a shaft rotatably mounted therein, and an expeller to pump fluid from the seal cavity. A dynamic seal provides a fluid tight seal between the housing and the shaft. The seal comprises an axially movable primary seal ring which rotates with the shaft and a mating stationary seal ring, both rings disposed annularly of the shaft and each defining a generally radial sealing face adapted to seal against the other. A biasing device urges the primary seal ring into sealing engagement with the mating seal ring. The radial face of the mating seal ring defines a plurality of spiral grooves and a sealing dam area which is at the periphery of the ring exposed to high pressure. When the pump is not operating, the seal ring faces contact one another and the dam provides a seal against the opposing face.

Abstract: An impeller pump including a housing defining a seal cavity having a shaft rotatably mounted therein, and an expeller to pump fluid from the seal cavity. A dynamic seal provides a fluid tight seal between the housing and the shaft. The seal comprises an axially movable primary seal ring which rotates with the shaft and a mating stationary seal ring, both rings disposed annularly of the shaft and each defining a generally radial sealing face adapted to seal against the other. A biasing device urges the primary seal ring into sealing engagement with the mating seal ring. The radial face of the mating seal ring defines a plurality of spiral grooves and a sealing dam area which is at the periphery of the ring exposed to high pressure. When the pump is not operating, the seal ring faces contact one another and the dam provides a seal against the opposing face.