DOUBLE GAS SEAL WITH COPLANAR PAD FACES.

摘要

A double gas pressure seal (10) is provided for sealing between a stationary housing (14) and a rotary housing (26). The gas pressure seal includes a stationary ring (42) and a rotary ring (40) each having a radially inner sealing face and a radially outer sealing face. A biasing spring (56) biases one of the rings toward the other ring. An annular groove (68) is provided in one of the rings, with the groove being spaced between the radially inner sealing faces and radially outer sealing faces. A supply port (84) supplies pressurised gas to the annular groove at a pressure higher than the process fluid in the stationary housing. A plurality of radially inner and radially outer recesses (94, 96) are provided on the one of the rings, and corresponding feed channels (98, 100) fluidly interconnect the annular groove with a rotary leading portion of each respective recess. A small quantity of pressurized gas escapes between the inner sealing faces to atmosphere and between the outer sealing faces to the process fluid sealed in the stationary housing.