FIELD: automatics, systems controlling technological processes. SUBSTANCE: increased reliability and accuracy of measurement of flow rate of fluid medium with provision for invariance to measurement of density, temperature, pressure and composition of fluid medium are achieved by formation of two streams isolated from each other (measurement and reference) running out into separate check regions from one forming region in agreement with quadrature law by which rate of jet flow is equal to square root of double difference of pressure in forming region and pressure in check region divided by density of fluid medium. Of these two jet flows there are formed corresponding enforced flows, one of them being measurement one, directed in opposition to measured flow and the other one being reference one directed perpendicular to it. In each jet flow rate is measured along specified measured length. Flow rate of fluid medium is determined as square root from difference of squared rate of reference flow and squared rate of measurement flow. EFFECT: increased reliability and accuracy of measurement of flow rate of fluid medium. 3 cl, 1 dwg
