JPS594647B

An apparatus for measuring the flow rate of a gaseous or liquid medium includes a baffle member which is poised in the stream on an elastic holder and permitted to execute inherent periodic motions. The flowing medium exerts a damping action on the moving element and the energy lost to the medium is related to the flow rate. The inherent velocity of the baffle is sensed by an inductive velocity sensor and the resulting signal is used to alter the current through a coil which produces an accelerating magnetic field that acts on conductors rigidly attached to the baffle. Thus, the energy required to maintain the inherent motions of the baffle is known and the flow rate may be inferred.