| 摘要 |
PROBLEM TO BE SOLVED: To provide a mass flow controller which can perform flow control with a wide dynamic range. SOLUTION: The mass flow controller has an opening control valve 4 which controls the flow of fluid passing in a channel 2; a pressure sensor 7b disposed on the downstream side of the control valve 4, a throttling part 6 disposed on the downstream side of the pressure sensor 7b; a flow sensor 5 which measures the flow rate F of the fluid passing in the channel 2; and a control unit 8 which controls the flow rate F of the fluid passing through the throttling part 6 by controlling the control value 4 using the output Spb of the pressure sensor 7b when controlling a large flow rate, and at the same time controls the flow rate F of the fluid passing through flow sensor 5 by controlling the opening/closing of the control valve 4 by using the output of the flow sensor 5 when controlling a small flow rate, thereby permitting flow rate control with a wide dynamic range. COPYRIGHT: (C)2004,JPO&NCIPI
|
