Patent ID: 6213473
Filing Date: 2001-04-10
Classification: F16J

Abstract:
A double gas pressure seal for sealing between a stationary housing and a rotary housing, the gas pressure seal sealing process fluid within the stationary housing, the gas pressure seal comprising:a stationary ring having an annular stationary pad radially inner sealing face and an annular stationary pad radially outer sealing face;a rotary ring having an annular rotary pad radially inner sealing face for sealing engagement with the annular stationary pad radially inner sealing face and an annular rotary pad radially outer sealing face for sealing engagement with the annular stationary pad radially outer sealing face;an annular groove in a sealing face of one of the stationary ring and the rotary ring, the annular groove being spaced radially between the radially inner sealing faces and the radially outer sealing faces;a supply port in the stationary ring for supplying pressurized gas from an external source to the annular groove, the pressurized gas being at a pressure higher than the pressure of the process fluid within the stationary housing;a plurality of circumferential spaced radially inner recesses each in one of the stationary ring and the rotary ring, each inner recess being spaced radially between the annular groove and a radially innermost portion of the radially inner sealing faces for receiving the pressurized gas to exert a pressurized gas lift-off force on an axially moveable one of the stationary ring and the rotary ring, each of the plurality of inner recesses having a rotary leading portion and a circumferentially spaced rotary trailing portion;a plurality of circumferentially spaced radially outer recesses each in one of the stationary ring and the rotary ring, each radially outer recess being spaced radially between the annular groove and a radially outermost portion of the outer seal faces for receiving the pressurized gas to exert a pressurized gas lift-off force on of the axially moveable one of the stationary ring and the rotary ring, each of the plurality of outer recesses having a rotary leading portion and a circumferentially spaced rotary trailing portion;a plurality of inner feed channels in one of the stationary ring and the rotary ring, each inner feed channel fluidly connecting the annular groove to the rotary leading portion of a respective inner recess to supply pressurized fluid to the inner recess, such that the rotary trailing portion of the respective inner recess is circumferentially spaced from the respective inner feed channel; anda plurality of outer feed channels in one of the stationary ring and the rotary ring, each outer feed channel fluidly connecting the annular groove to the rotary leading portion of a respective outer recess to supply pressurized fluid to the outer recess, such that the rotary trailing portion of the respective outer recess is circumferentially spaced from the respective outer feed channel.