Face seal with double spiral grooves

A mechanical seal construction comprising a stationary housing, a shaft rotatably supported in said housing, a pair of relatively rotatable sealing rings surrounding said shaft, one of said rings being rotatable with said shaft and the other being fixed relative to said housing, said rings having confronting, generally radial faces, means normally biasing one of said rings toward other, said rings having a first set of circumferential edges adapted to be exposed to a fluid under pressure to be sealed in said housing and having other circumferential edges adapted to be exposed to a lower pressure outside of said housing, spiral groove means in the confronting face of one of said rings, said spiral groove means including a plurality of uniformly disposed downstream pumping grooves formed to communicate with the fluid to be sealed at said circumferential edge of said ring adapted to be exposed to the fluid under pressure and extending toward said other circumferential edge of said one ring, the downstream pumping grooves having an included angle at the point of intersection with a tangent of the circumferential edge of said ring which is exposed to the fluid under pressure, said downstream groove included angle being in a range of from 5.degree. to 20.degree., said downstream pumping grooves being operable during rotation of said shaft to pump fluid from said circumferential edge exposed to the fluid to be sealed toward the other circumferential edge of said ring, said spiral groove means further including a plurality of uniformly disposed upstream pumping grooves intersection only a respective one of said downstream pumping spiral grooves and inclined oppositely thereto, the upstream pumping grooves having an included angle at the point of intersection with the tangent of the circumferential edge of said ring which is exposed to the relatively lower pressure in the environment outside of said housing, said upstream pumping groove included angle being in a range of from about 5.degree. to about 20.degree., said upstream pumping grooves operable to pump fluid which is between said confronting ring faces back toward said circumferential edge exposed to the fluid to be sealed, said downstream pumping grooves terminating at the intersection thereof with said upstream pumping grooves.