| 摘要 |
PURPOSE:To sense a liquid level without contact with the liquid level by forming a sensor so that setting positions of a light outgoing part and a light incident part are respectively gradient at an equal angle with respect to a normal direction of a reflecting surface on a vessel inner wall. CONSTITUTION:A light outgoing part 11 applies light led from a light source 10 by an optical fiber 13 to a vessel 7. A light incident part 12 admits light reflected by the vessel 7 and the light is led by an optical fiber 14 to be received by a light receiving element 15. The light outgoing part 11 and the light incident part 12 are gradient with respect to a normal axis at an angle theta, which is appropriately set according to a refractive index of the vessel, a refractive index and absorbance of liquid, etc. A light reception signal received by the light receiving element 15 is input to a liquid level determining circuit 16, where determination is made as to whether the liquid level reaches the positions of the light outgoing and incident parts 11, 12 in the vessel 7 based on the light reception level. When the liquid level has reached based on the determination results, the circuit 16 informs it by a buzzer 17 or a lamp 18. |
