Device for measuring flow rate of fluid medium

The present invention relates to the field of measuring the parameters of a flow of a fluid medium flowing through a pipeline. A measurement device for measuring, in the main direction of a flow, the flow rate of a fluid medium flowing in a pipeline, contains a deflector assembly which is connected to the pipeline and which is capable of deflecting the flow of fluid medium away from the axis of the main direction of the flow in the pipeline and of redirecting the flow into a measurement section; the deflector assembly is in the form of a hermetic reservoir having an input portion which is connected to an input pipeline, an output portion which is connected to an output pipeline, and a deflector portion which is connected to the input portion and to the output portion and which contains a tubular element which is located at least partially in the deflector portion and output portion; the tubular element has a measurement section, which is provided with means for measuring the flow rate of a fluid medium, and a