| 摘要 |
PURPOSE:To heighten resolving property in the detection of liquid level and enable automatic reading with high accuracy, by using two semiconductor optical units and prisms. CONSTITUTION:Light source lamps 2 and triangular prisms 3 are so placed that they face each other across the liquid level detection parts 8a, 8b of a U-shaped tube 8. Semiconductor optical units 4a, 4b are provided in a vertically symmetric positions over and under each triangular prism 3, one vertex edge of which faces the lamp 2. Liquid level detectors 6a, 6b are thus constituted. The output of each of the detectors 6a, 6b takes a peak value when the liquid level coincides with the height of said vertex edge of the triangular prism 3. Feedback is effected to always place the detectors in the position of the coincidence. The detectors 6a, 6b are moved on screw rods 11a, 11b by pulse motors 10a, 10b. At that time, the positional relation between the liquid levels is determined by a length measuring unit 7. This results in avoiding the influence of the change in the characteristics of the semiconductor optical units due to that in the temperature or the like. |
