| 摘要 |
PURPOSE:To make a flow meter safe in respect to explosion-proof properties, by detecting the variance of the rotation number of a movable part as the variance of the quantity of light of rays led out from a magnetooptic modulator to measure the flow rate of a fluid to be measured. CONSTITUTION:The light from a light source 5 reaches a magnetooptic modulator 4 through an optical fiber 6 and is propagated internally while being fully reflected and reaches a photodetector 8 through an optical fiber 7 and is displayed as a flow rate display in the reference state. When a fluid to be measured is flowed into a duct 1, a movable part is rotated in the direction of an arrow in accordance with its flow rate, and a rotary blade 23 goes away from the magnetooptic modulator 4, and a rotary blade 22 approaches the magnetooptic modulator 4. The density of the magnetic flux between a permanent magnet 3 and the movable part is changed by the rotation of rotary blades 22-25, and the quantity of light reaching the photodetector 8 is changed in accordance with this change, and this optical information signal is subjected to the operation processing, and a value displayed on a display indicates the flow rate of the fluid to be measured flowing into the duct 1. |
