Abstract: A device for measurement of fluid flow in a conduit comprising a housing having an upstream end formed with a fluid inlet, a downstream end formed with a fluid outlet, a fluid flow path extending between the inlet port and the outlet port and having longitudinal axis, and one ore more flexible leaves fixedly mounted within the housing and extending into the fluid flow path, each having a leaf axis normal to a leaf plane, the one or more leaves being deformable responsive to fluid flow rate within the conduit. A measuring system for measuring deflection rate of each leaf responsive to fluid flow within the conduit and for generating a rate signal corresponding with the deflection rate, and a processor unit for processing the rate signal and converting it to an output signal indicative of fluid flow rate within the conduit.