| 摘要 |
PROBLEM TO BE SOLVED: To provide a shaft seal mechanism and a vacuum pump which are improved in problems such as pollution of treated gas due to lubricating oil and deterioration of the lubricating oil due to the treated gas. SOLUTION: In a shaft seal mechanism of a gas pump, a shock absorbing chamber 21 which is determined by two seal means 21a, 21b is formed between a bearing chamber 11 and a pump chamber 2. Gas is charged into the shock absorbing chamber 21, while it is suctioned and discharged from a portion between the bearing chamber 11 and the shock absorbing chamber 21. The pressure of the gas in the shock absorbing chamber 21 is kept higher than the gas pressure in the pump chamber and suction/discharge pressure for the gas. |
