| 摘要 |
PURPOSE:To detect the position of the liquid level to be detected continuously and to make size small and also to prolong life by providing a light emitting element and a photodetector in the upper part of a long cylinder, placing a float in the long cylinder, and detecting the quantity of the liquid reflected from the float. CONSTITUTION:A long cylinder 1 has outlets and inlets 2a, 2b for liquid and air in the bottom and upper parts. A float 3 placed therein moves vertically according to the displacement of the liquied level A to be detected. At this time, part of the light emitted from a light emitting diode 4 is reflected by the top surface of the float 3, advances backward and arrives at a phototransistor 5, but the quantity of the arrived light changes with the position of the float 3 on account of the attenuation by the spreading of the light beam and the reflection on the inside wall of the long cylinder 1. Hence, the position of the float 3, that is, the level of the liquid to be measured is detected from the output of the phototransistor 5. |
