Vortex flow meter

The present invention relates to a flow meter for measuring the flow of a fluid, such as air or liquid running in a measuring tube, accurately throughout a wide range. A vortex flow meter includes a measuring tube in which a fluid is carried, a vortex generator provided in the measuring tube for developing a Karman vortex in the fluid, a magnetic field generator generating a magnetic field across the measuring tube downstream of the vortex generator, a pair of electromotive force measuring electrodes provided downstream of the vortex generator for measuring an electromotive force generated by the Karman vortex passing across the magnetic field, a pair of reference electrodes provided at locations upstream and downstream of the electromotive force measuring electrodes, respectively, for measuring a potential at each location, and a detector circuit electrically connected to the electromotive force measuring electrodes and the reference electrodes for calculating the flow of the fluid from the electromotive force and the potential measured by the reference electrodes. The flow is calculated by subtracting the potential difference of the reference potential measuring electrodes from the electromotive force measured by the electromotive force measuring electrodes. This allows the flow meter to have an increased measuring range, meet a wide range of flow conditions, have a simple construction, and have measurement accuracy.