| 摘要 |
PURPOSE:To discharge automatically with an ion pump acting as a prime pump by monitoring a leak, etc. of the system with the vacuum meter of the front stage of an ion pump and by monitoring the ion pump with the ionization current. CONSTITUTION:When a switch 10d is depressed at time t1, a rotary pump is started by the signal of a control circuit 10 and also a vacuum valve 7 is opened for roughing down. When the pressure in the system 1 to be discharged is confirmed to have reduced to the action region of a diffusion pump 5, a control circuit 10 opens the valve 7 at time t2, the discharge by the diffusion pump 5 is started and a vacuum meter 9 is made operational. As a result, the pressure of the system 1 to be discharged is further reduced, and when the detection pressure signal of a control circuit 10 is made to correspond to the action region pressure P1 of an ion pump 2 at time t3, a switch 4a signal is sent to start a driving power supply 4, thus the ion pump 2 starts discharging and the discharge is progressed. When the detection pressure of the vacuum meter 9 is reduced to a pressure P3 allowing the single-handed discharge by the ion pump 2, the valve 7 is closed at time t4 by the control circuit 4, and the discharge is continued by the ion pump 2 alone. |
