| 摘要 |
PURPOSE:To securely prevent a corrosive gas from entering a machine room by once increasing the flow rate of a gas purging gas which is introduced into said machine room synchronized with the entrance of a corrosive gas into a pump room and, then, adjusting to a defined flow rate and exhausting said corrosive gas. CONSTITUTION:A gas purge valve GPV is opened in the position of a port I, interlocked with the opening of a gas valve GV by a control means C. And, a large quantity of gas purging gas is introduced into the machine room 2 of a turbo molecular pump TMP at a timing synchronized with the entrance of a corrosive gas into the pump room 1 of the pump TMP. Thereby, the pressure P1 in the pump room 1 and the pressure P2 in the machine room 2 can be kept in a relation of P1>=P2 even with such a sudden entrance of the corrosive gas. By shifting said GPV to the position of port II interlocked with the throttling of a main valve MV after feeding the corrosive gas, the pressure P2 can be gradually reduced down to the stationary level in response to reduction in the pressure P1, enabling gas purging by means of a minimal required quantity of gas and securely preventing the phenomenon of polluting and corroding the machine room 2.
|
