WASHING DEVICE

PURPOSE:To sense the turbidity of a washing liquid consisting of an organic solvent simply and judge the timing of replacement precisely by forming a turbidity sensing device from a light emitting element and a light receiving element, and giving a specific value (in nm) of wavelength to the light emitting element. CONSTITUTION:A turbidity sensing device 4 is chiefly composed of a light emitting element 8 consisting of LED, etc., and a light receiving element 9 consisting of amorphous visible-ray all-spectral sensor, etc., which accepts visible rays. Signals from a microcomputer 1 are amplified by a reception side amplifier 10 for driving the emitting element 8, while the output signal of the receiving element 9 is given to the microcomputer 1 via a reception side amplifier 11. The emitting element 8 is so arranged as to emit blue light having a wavelength below 500nm, preferably ranging from 430 to 470nm. The photo-transmissivity of the emitting element 8 and the photo-reception quantity of the receiving element 9 drop with progress of contaminating of the washing liquid, and therefrom the degree of contamination of the liquid is determined.