| 摘要 |
A photo detecting flow sensing bending beam fluid flow switch and flow meter system having blocking targets that selectively block the optical path from an emission source to a photodetector. The device provides a system which is very sensitive to fluid flow in a pipe, container or duct by providing a shaped flexible flow sensitive bending beam having a blocking target which is bent so that the portion of the blocking target is displaced between the emission source and a photodetector. The shaped blocking target is configured to either interrupt or permit the transmission of emission from the emitter to the photodetector. The presence or absence of the source represents the presence or absence of a fluid flow rate above or below a selected value thus, performing a fluid flow switch function. By modifying the blocking target to provide a reflective control from an emission to a photo detector or an absorption of the emission by a target varying in opacity, the relative light output is continuously modulated to produce a voltage output directly proportional to the rate of fluid flow past the target on a flow sensitive bending beam. In an optional embodiment, flow sensitivity is improved by adding vortex shedding enhancements to the flow sensitive bending beam. This combination of functional elements can provide an analog fluid flow meter transducer for flow metering, totalizing in a flow monitoring system having single or multiple flow switching set points.
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