| 摘要 |
PURPOSE:To provide a titled device which adjusts easily a vacuum atmosphere and enables simplification of the device by the constitution in which the introducing amt. of a gas is selectively controlled by the deviation between the detected value of the flow rate of the gas to a vacuum vessel or the pressure of the vacuum vessel and respective set values. CONSTITUTION:The flow rate of the gas to be supplied via a flow rate control valve 13 to a vacuum vessel 11 to be evacuated by a vacuum pump (not shown) is detected by a flow rate sensor 21 and is outputted to the 1st comparator circuit 23 where the detected flow rate value and the set value signal from a flow rate setting circuit 25 are compared and the deviation is detected. On the other hand, the detection signal of the pressure in the vessel 11 detected by a vacuum gage 29 is outputted to the 2nd comparator circuit 31 where the pressure detection signal and the pressure set signal from a pressure setting circuit 35 are compared and the deviation is detected. The valve 13 is then operated via a valve actuating member 19 by a selecting switch 27 having contact points 27a, b, c in such a way that the deviation of the flow rate or the pressure is selectively made zero. The inflow rate of the gas to the vacuum vessel 11 is thus adjusted. |
