| 摘要 |
PROBLEM TO BE SOLVED: To control the opening and closing of a valve so that a flow rate approaches a value regardless of dead zone width in a flow rate controlling method and device for controlling a flow rate. SOLUTION: A flow rate set value is inputted, and the opening and closing direction of a valve is judged according to the difference between the flow rate set value and a flow rate measured value at this present point of time, and the opening and closing operation of the valve is started according to the judged result. Also, time measurement is started, and a time until the flow rate measured value reaches a primary target value corresponding to the flow rate set value can is measured so that flow rate changing amounts per unit time can be calculated. Then, the opening and closing operation of the valve is temporarily stopped, and the opening and closing operation time of the valve until the flow rate set value is reached is calculated on the basis of a flow rate being the difference between the flow rate measured value after the lapse of a fixed time and the flow rate set value and the flow rate changing amounts per unit time, and the opening and closing operation of the valve is started.
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