| 摘要 |
PURPOSE:To measure accurately even a liquid level of a tank having high pressure and to increase the storage efficiency of the tank without impairing the performance of a heat- insulating material, by measuring the liquid level by means of a combination of a light-wave distance measuring unit, an optical fiber, a cube mirror, a lens system, etc. while correcting a measured value by means of a comparing standard scale. CONSTITUTION:When a pulse of laser light is generated by a light-wave distance measuring unit 13, the laser light proceeds through a passage of the distance measuring unit 13, a selector switch 12, a lens system 10, a cube mirror 8, the lens system 10, the switch 12 and the distance measuring unit 13 in the case when connection is made to an optical fiber 9. The entire-length distance of the passage is determined from the measurement of a time required for this process, and the height of a liquid level from the lens system 10 to the mirror 8 can be measured therefrom. In the case when the pressure of a tank 1 turns high and the speed of a light wave turns slow, the switch 12 is changed over to connect with an optical fiber 29. Then the laser light proceeds through a passage of the distance measuring unit 13, the switch 12, a lens system 30, a mirror 28, the lens system 30, the switch 12, the distance measuring unit 13 and a comparing standard scale 21, and the correction of a measured value is enabled on the basis of the measurement of a time for transmission through this passage. |
