| 摘要 |
<p>PURPOSE:To more accurately control the flow rate of gas and to quickly discover abnormality by providing two bypass lines for detecting the flow rates of the gas. CONSTITUTION:The flow rate of the gas flowing through a flow rate detecting bypass 2a is converted to an electric signal by a measuring self-heating resistor 3 and a detection and amplifying circuit 5a, and the electric signal is compared with the signal inputted from a flow rate setting device 7 by a comparing control circuit 6 and a thermal valve 4 is driven to control the flow rate of the gas flowing through a gas line 1. At this time, the signal is also sent to a flow rate display device 8 from the detection and amplifying circuit 5a to make it possible to know the flow rate. Separately, the flow rate of the gas flowing through a flow rate detecting bypass 2b is detected to be displayed on a monitoring flow rate display device 9. By comparing the displayed flow rate of the flow rate display device 8 with that of the monitoring flow rate display device 9, the accurate flow rate of the gas flowing through the gas line 1 and the abnormality of a mass flow controller can be known.</p> |
