To make it possible to improve the accuracy of detecting flow rate and the reliability of a flow rate detector by providing a second magnet for rockably supporting a flat plate by the magnetic attraction to the first magnet of the plate.
A flapper-like flat plate 12 is pivotally supported between a first magnet 13 provided at the plate 12 and a second magnet 14 disposed outside a pipeline 11 by the attraction of a magnetic force. The plate 12 is rocked according to the pressure of fluid flowing through the pipeline 11. In this case, since the rocking angle of the plate 12 has correlation with the flow rate of the fluid, the magnetic force of the magnet 13 acts on a reed switch 15 when the flow rate of the fluid becomes a specific value or more, and hence the switch 15 is turned on. Thus, the specific value or more of the flow rate of the fluid in the pipeline 11 can be detected. Since the plate 12 is not set to the pipeline 11, there is small fear is catching dusts and it makes it possible to accurately detect the flow rate.
FUSE AKIRA
SUGIYAMA YOSHIYUKI
TSUDA YUJI
IWAKI OKIHIRO
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