A liquid ring pump having:
- an annular housing extending along a longitudinal axis,
- a shaft extending along a longitudinal axis and means for mounting said shaft for rotation about the longitudinal axis thereof with the longitudinal axis of said shaft substantially parallel to and spaced from the longitudinal axis of said housing wherein said shaft is eccentrically positioned within said housing,
- a rotor fixedly mounted on said shaft and having a plurality of blades, each of blades extending along and substantially radially outwardly of the shaft relative to the longitudinal axis of said shaft, said blades being spaced from one another about said shaft relative to the longitudinal axis of said shaft,
- means for introducing liquid into said housing wherein said rotating shaft and rotor create an annular ring of liquid extending substantially symmetrically about the longitudinal axis of said housing and eccentrically about the longitudinal axis of said shaft, said liquid introducing means including a portion fixedly mounted relative to said housing, said portion extending about and along said shaft and radially spaced from said shaft to define a chamber between said portion and said shaft, said chamber extending longitudinally along said shaft from a first location to at least a second location, said second location being longitudinally spaced from said first location along said shaft, said liquid introducing means further including means for admitting liquid into said chamber and further including means for admitting liquid from said chamber into said housing through at least one make-up passage located substantially closer to said second location than to said first location,
- port means fixedly mounted relative to said housing, said port means having an inlet passage for admitting gas into said rotor and an outlet passage for discharging gas from said rotor, said liquid ring pump drawing gas into said rotor through said inlet passage at a first pressure and discharging said gas from said rotor through said outlet passage at a second, higher pressure,
- sealing means extending between said portion of said liquid introducing means and said shaft at said first location of said chamber for sealingly engaging said shaft and said portion of said liquid introducing means radially about the longitudinal axis of said shaft to prevent fluid and fluid pressures generated in said pump from passing between said fixed portion of said liquid introducing means and said rotating shaft, said sealing means defining and separating an inboard side including said chamber subjected to the pressures generated by said pump and an outboard side isolated and sealed from the chamber and the pressures generated by said pump, said chamber and said inboard side of said sealing means being subjected substantially to the full, second pressure generated by said pump, and
- means located substantially closer to said first location of said chamber than to said second location for aspirating fluid at said second, higher pressure from next to said shaft in said chamber on the inboard side of said sealing means substantially adjacent said first location, said aspirating means including at least one passage extending between and in fluid communication with the fluid in said chamber adjacent said shaft at said second, higher pressure and the inlet passage of said port means and said gas at said higher pressure wherein said fluid at said second, higher pressure next to said shaft on the inboard side of said sealing means substantially adjacent said first location is aspirated into the gas being drawn into the rotor through the inlet passage of said port means.