| 摘要 |
PURPOSE:To prevent the malfunction by making a light incident at a prescribed angle onto the inside face of a tube which the surface of a liquid passes and detecting the variation of the exit position difference between presence of the liquid in the incident position and absence of the liquid in this position by a light receiving means. CONSTITUTION:When a liquid surface J passes between a light emitting diode, which is provided in a center part 4A' of a ball 4A, and an optical fiber 8, the quantity of light received by the optical fiber 8 is changed, and a trigger signal is generated from a photodetector 9 to reset a counter 13 and a display device 15. When the liquid surface J falls to pass a measure part 4a, a trigger signal is generated from a photodetector 10 and is outputted to the counter 13, and the counter 13 starts counting pulses from a reference oscillator 14. When the liquid surface J falls furthermore to pass a measure part 4b, a trigger signal is generated from a photodetector 11 and is outputted to the counter 13, and the counter 13 stops counting pulses. The liquid surface passage time between measure parts 4a and 4b is displayed on the display device 15. |
