| 摘要 |
PROBLEM TO BE SOLVED: To provide a flow control technique of a flow control valve with which satisfactory flow control can always be performed in dependent of fluctuations in an incoming water pressure. SOLUTION: Characteristics (a) are obtained by converting the characteristics of the flow rate and valve position of a flow control valve to logarithmic values. In these characteristics, the relation between the valve position and the flow rate (logarithm) is approximated as a linear representation while the difference of incoming water pressure to the flow control valve is indicated as an inclination of the above characteristics. Thus, the inclination of these characteristics is obtained from a flow rateΔLog (flow rate)) per unit change in the valve aperture, and based on this inclination, valve position is controlled. Besides, the fluctuation in the incoming water pressure or the like can also be dealt with by shortening an interval (control cycle) (t) to obtain this inclination.
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