| 摘要 |
<p>PURPOSE:To retain concentration in a water tank within an allowable range by providing prescribed stirring waiting time after one time opening operation of control valve by valve-opening means and retarding motion by comparing means for prescribed time. CONSTITUTION:In a concentration control device provided with concentration detection means, control valve, etc., comparing means for comparing detection value obtained by signal from concentration detection means with set value having previously set concentration of aqueous solution, valve-opening means for subjecting control valve to opening operation by prescribed open retaining time when the detection value is judged to set value or below by the above- mentioned comparing means and waiting time providing means for retarding motion by comparing means for prescribed time by giving prescribed stirring time after one time open operation of control valve by the valve-opening means are provided and, as necessary, further alarm means for giving alarm when a series of motions by comparing means, valve-opening means and wait time providing means continue for time more than set time is provided.</p> |
