| 摘要 |
PURPOSE:To reduce the leakage of a low temperature coolant even for the variation in the supplying conditions of the coolant and to shorten the axial length by supplying control gas to the suitable position of the shaft seal in noncontact manner. CONSTITUTION:Control gas q2 of pressure P2 slightly lower than the low temperature coolant supply pressure P1 is supplied to an annular groove 12a through a control gas inlet 13a and a fine hole 12b. The gas q2 is regulated to reduce the pressure of the high pressure coolant gas of a refrigerator. The annular brush 12 of the shaft seal is floated from the end face of a hollow disc 11 at a narrow gap (delta) to the hollow disc 11. The leakage q1 to the exhaust side of the low temperature coolant can be arbitrarily controlled by the pressure P2 of the gas q2. |
