| 摘要 |
PURPOSE:To improve response of a pneumatically-operated valve, by a method wherein a valve opening demand signal is compared with a valve opening signal, and if a deviation there-between is wide, other exhaust port than an ordinary air exhaust port is opened. CONSTITUTION:Movement of a valve rod 19 is detected by a valve opening detector 10, a signal therefrom is sent to a valve opening converter 11 to convert it into a standardized electric signal. The signal is sent to opening switches 12 and 13 to respectively provide a valve full-opening and a valve full-closing contact signal therefrom. A valve opening signal is sent to a subtractor 14 by which a difference between the valve opening signal and a valve opening demand signal is computed, and a difference signal therefrom is sent to a deviation switch 15. When a valve is brought into a valve opening mode from a valve full-closing mode through operation of switches 12-14, a valve opening exhaust valve 16 is opened. When it is brought into a valve closing mode from a valve full-opening mode, a valve closing exhaust valve 17 is opened. Rapid exhaust results in shortening of the lag time of a valve.
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