| 摘要 |
PURPOSE: To judge the presence of a liquid in a pipe or vessel in no-contact by photoelectrically converting the reflected light from the inner surface of an optical transmitting material to the incident light from the outer surface of the optical transmitting material, and arithmetically operating the photoelectrically converted output. CONSTITUTION: When a light emitting means 22 and a prism 24 are properly arranged when a liquid is not accumulated to the sensor part 10 of a vessel, the refracted light is totally reflected by the inner surface of a transmitting material 2, the reflected light is converted into an electric signal through a prism 32 and a photoelectric converting element 34, and arithmetically processed by a control means 100, and the absence of a liquid 6 on the inner surface is detected from a large reflected light quantity. On the other hand, when the level of the liquid 6 is raised higher than the total reflecting point 01 of the sensor part 10, no total reflection is caused in the total reflecting point 01, and the reflected light quantity is sharply reduced. This reduced reflected light quantity is revealed as the output change of the photoelectric converting element 34, and the output fluctuation of the element 34 is detected by the control means 100, whereby the presence of the liquid 6 on the inner wall point 01 can be detected. |
