| 摘要 |
PURPOSE:To substantially eliminate influence of an ambient temperature and a charged liquid temperature, by detecting a liquid level in accordance with a temperature difference of 3 points. CONSTITUTION:A temperature measuring means 1 for detecting a level sends standard light through a half-mirror 12 from an irradiation lamp 13, infrared rays which have passed through a lens 11 from 3 points A, B and C are detected by a detector 15 through the mirror 12 and a chopper 14, and by this detecting value, level switches SW1, SW2 are operated. When the liquid level reaches a prescribed level and a temperature difference between the point A and the point B exceeds a set value t1, the switch SW1 is turned on, also a temperature difference between the point B and the point C becomes <= a set value t2, and the switch SW2 is also turned on. (provided t1>t2). Accordingly, influence of an ambient temperature and influence of a charged liquid temperature are eliminated substantially, and a high level measuring accuracy is realized. |
