| 摘要 |
PURPOSE:To stabilize the concentration of liquid in a tank between an upper and a lower limit value all the time by comparing the concentration with a set value, replenishing high-concentration or low-concentration liquid, and starting concentration control after the liquid concentration in the tank becomes stable. CONSTITUTION:When the concentration of the alkali solution 2 in a washing tank 1 decreases below the lower-limit set value, a constant amount of 5% alkali solution is replenished into the washing tank 1 and when it increases above the upper-limit set value, a constant amount of pure water is replenished into the tank 1. Then, said replenishment (concentration control) is interrupted for a specific time by timers incorporated in controllers 8 and 12, and once the concentration of the alkali solution in the tank 1 becomes constant, the replenishment control (concentration control) is restarted. Thus, the alkali solution 2 in the tank 1 is controlled to concentration within the specific range all the time. |
