Abstract: 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.

Abstract: A fluid flow monitoring system comprised of a permanent magnet mounted on a bendable spring blade that provide an output from a Hall effect transducer as the permanent magnet is deflected toward the transducer. The permanent magnet can be mounted to directly approach the Hall effect transducer or can also be mounted to approach the transducer by a sideways bypass direction. Both the direct motion and sideways bypass direction allows the use of a variety of sizes and shapes of magnets that allow the magnetic field intensity to be modified in any way desired. Various magnet shapes such as cylinders, rectangles, pyramids, triangles or compound magnets from these shapes may be used. The output signal of the transducer is processed through a smoothing filter and circuits that produce a linear output or a stepped digital output. The system preferably uses a resistance/capacitance filter to provide a different time constant for an increasing flow or a decreasing flow.