PURPOSE: To eliminate the need for an auxiliary motor and restrict the amount of barrier oil used to the minimum by arranging a barrier system with a disc mounted concentrically with a rotating compressor shaft as the main body between a bearing and a suction side labyrinth seal in a bearing chamber.

CONSTITUTION: A dynamic barrier system 23 is arranged between a bearing and a labyrinth seal in a compressor chamber 19. The dynamic barrier system 23 secures a disc 24 on a compressor shaft 5. An inverted U-shaped rim 25 is arranged on the disc 24. A stator ring 26 is arranged in the rim 25 and secured on a wall 27 of a chamber 16. Barrier oil is supplied via a branch 31 and a small hole 30 to a small passage 28 formed by the stator ring 26 and the disc 24. A wedge 32 is formed at the side facing the disc 24 in the stator ring 26 and is inserted in a cavity 33 in the disc 24. An annular deflector tooth 34 projecting beyond the outer annular edge 35 of the cavity 33 is attached to the stator ring 26.