| 摘要 |
PURPOSE:To execute uniform washing in proper quantities while using the purity of pure water in a treating tank as an index by providing a simple resistivity measuring instrument measuring the resistivity value of pure water in the treating tank. CONSTITUTION:A resistivity sensor 7 consisting of opposite electrodes and a temperature sensor 8 are set up in the treating tank 1, and the sensors 7, 8 are connected to a micro-computer 9. The computer 9 impedance-converts voltage between the opposite electrodes of the sensor 7, and computes the resistivity value of washing water in the tank 1 from the impedance value. A temperature coefficient obtained about the resistivity value of standard pure water is memorized previously to the computer 9, and the computing value is multiplied by a temperature coefficient at a detecting temperature of the sensor 8 and the temperature is compensated. When the resistivity value reaches the resistivity value of washing water in case of the completion of washing memorized previously, the computer 9 outputs a wash-completion signal, and the operation of the pure- water washer is stopped. Accordingly, uniform washing can be executed in proper quantities at all times. |
