PURPOSE: To adjust the detergent concentration of a detergent liquid solution within a washing bath simply and easily by converting the conductivity of the measured detergent liquid solution to the detergent concentration by using a specific expression and then comparing it with a preset detergent concentration.
CONSTITUTION: A conductivity Y of a washing liquid solution 2 within a washing bath 1 is measured by a sensor 4 and the conductivity Y is converted into a detergent concentration X by an expression Y=aX+b (Y: Conductivity of detergent liquid solution, X: Washing concentration. a: Coefficient peculiar to detergent. b: Conductivity of solvent medium). The detergent concentration X (% concentration) is compared with the upper and lower setting values which a proper concentration range of the set detergent liquid solution 2 indicates, a detergent supply means 5 is controlled based on the comparison result, and then a detergent stock solution 6 is supplied to or cut off to the washing bath 1, thus enabling the detergent concentration X to be controlled. The display, input, etc., of the measured and set values can all be directly executed by using the detergent concentration X, thus enabling a work accompanying the change in a detergent to be simple even if the type of the detergent to be used is changed.
CLEAN TECHNOL KK