| 摘要 |
PROBLEM TO BE SOLVED: To provide an illuminance difference detection type level gage which enables relatively easy and direct measurement of the liquid surface in a storage tank difficult in direction measurement. SOLUTION: This illuminance difference detection type level gage has an optical fiber 4a for illumination and first and second fibers 4b and 4c for reception and the first and second fibers 4b and 4c for reception are made different in height. Light irradiated from the side of the lower end of the optical fiber 4a for illumination is received as scattered reflected light from the liquid surface from the side of the lower ends of the first and second optical fibers 4b and 4c for reception. The scattered reflected light is trapped by a photocell 6 on the side of the upper ends of the first and second optical fibers 4b and 4c for reception therethrough to monitor the illuminance difference with an illuminance difference gage 7. The light reception end as lower end side of the optical fiber 4b for reception is determined to reach the liquid surface by detecting the illuminance difference with the illuminance difference gage 7. Thus, the position of the liquid surface is calculated from the graduation in a stainless wire 8 and the drawing of a storage tank 2. |
