| 摘要 |
PROBLEM TO BE SOLVED: To provide an excellent method for supplying chemical in a concentration controlled manner and an apparatus used therefor wherein appropriate concentration control can be performed for a long term and there is no waste in an introduced dose. SOLUTION: A sensor for measuring conductivity in a cleaning tank, a pump 12 for putting an undiluted detergent into the cleaning tank, and a control section 14 are provided. The control section 14 controls operation of the sensor so that power is supplied to the sensor for an initial predetermined time per unit and no power is supplied for the rest of the time, where a unit is 50 msec to 1 sec. In addition, data measured at each initial time point after beginning of the power supply among measurement data for a unit intermittently input from the sensor is compared with a preset value of the conductivity, and operation of the pump 12 is controlled based on the result of the comparison to keep constant diluent concentration in a chemical supply tank.
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