The invention discloses a vortex
mass flow meter, comprising a measuring tube, a vortex generating body arranged in the measuring tube and a flow detection element. The measuring tube is composed of an inlet section, a contraction section, a
throat part, an extension section and an outlet section which are connected in sequence, the inlet section and the outlet section are straight round tubes with the same diameters, the contraction section and the extension section are conical tubes with the same conical degrees, and the
throat part is a straight round tube the inner
diameter of which is smaller than that of the inlet section; and the vortex generating body and the flow detection element are both arranged on the
throat part of the measuring tube. In the invention, the contraction section is used for adjusting flow field and improving flow speed, the extension section is used for restoring the
tube diameter contracted by the contraction section, and the contraction section and the extension section can improve the pressure loss of the measuring loss. By installing the vortex generating body and the flow detection element on the throat part of the measuring tube, due to the acceleration action when flow passes through the contraction section, the
lower limit flow value of a meter can be greatly reduced and the measuring range of the meter can be improved by measuring the flow at the throat part.