| 摘要 |
PURPOSE:To eliminate the need for incorporation of an electrode and a signal wire into a tank and to increase the reliability of an instrument, by converting a change of a liquid amount in a liquid storage tank to a color change and detecting sand change as an electric signal by a color sensor provided at the outside of the tank. CONSTITUTION:A float B is rotated in accordance with the liquid amount in the tank A, and the color of a colored plate G seen from a detecting window C is changed. A color sensor D absorbs and responds the color with the wavelength of light, output electric signal is calculated by an arithmetic circuit E and a level decision is performed by a level detecting circuit F. If a part (a) of the plate G is blue and a part (b) is red, the ratio of the blue to red colores seen from the window C is varied with the rotation of the float B. The sensor D outputs an optical signal equal to the case of absorption of the light of the wavelength corresponding to the center value between the wavelengths of blue and red colors in case when, e.g. blue and red colors (a), (b) appear in the window C at 1:1 ratio. |
