Patent ID: 9395000
Filing Date: 2016-07-19
CPC Classification: F16J

Claim Text:
1. A lift off seal including a particulate exclusion band, the lift off seal comprising: a stationary seal face having a substantially cylindrical outer periphery, the stationary seal face terminating at one end in a stationary sealing surface; a rotating seal face having a substantially cylindrical outer periphery, the rotating seal face terminating at one end in a rotating sealing surface, the stationary and rotating sealing surfaces being closely adjacent to each other so as to form a lift off region therebetween; a gas barrier region configured to contain pressurized barrier gas, the gas barrier region being in fluid communication with an inner periphery of the lift off region, so that pressurized barrier gas can flow from the barrier gas region into the lift off region, an outer periphery of the lift off region being in fluid communication with a process fluid; and a particulate exclusion band rotationally fixed to the outer periphery of the stationary seal face, said band being supported entirely by said stationary seal face and extending axially at least over the outer periphery of the lift off region and forming an annular cavity surrounding the outer periphery of the lift off region.