| 摘要 |
PURPOSE:To perform measurement of concentration with high reliability and thereby keep the working liquid in the best condition by preventing error in measurements through measuring the concentration of working liquid after sludge in the working liquid is removed by a filter. CONSTITUTION:Working liquid 10 including sludge is sent into an exhaust vessel 26, and the working liquid with minor sludge is sent to a filter 14 through a pump 30, where the sludge with a grain size of 1-2mu is filtered out and sent to the processing vessel 12 and, at the same time, part of it is supplied to a specific resistance measuring instrument 36 to determine its specific resistance. According to the value obtained, a solenoid operated valve 32 is opened and closed to maintain the overall specific resistance of the working liquid in supply liquid vessel 28 at the set value. |
