Basic principle of mass flow meter

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Structural principle of mass flow meters: A mass flow meter consists of three components: a sensor, a transmitter, and a digital indication accumulator. The sensor is made based on the Coriolis effect and consists of three parts: a sensing tube, an electromagnetic actuator, and an electromagnetic detector. The electromagnetic driver causes the sensor to vibrate at its natural frequency, while the flow of fluid induces a distortion in the U-shaped sensor due to the Coriolis force, creating a phase difference on its left and right sides. According to the Coriolis effect, this phase difference is proportional to the mass flow rate. The electromagnetic monitor converts this phase difference into a corresponding level signal, which is sent to the transmitter; after electrical processing such as filtering, integration, and amplification. It is output in two forms: a 4–20 mA analog signal proportional to the quality, and a frequency signal within a certain range. When a fluid flows through two parallel measuring tubes, an acceleration perpendicular to the direction of flow is generated, along with a corresponding Coriolis force. This force causes the measuring tubes to oscillate and twist, and this twisting phenomenon is known as the Coriolis effect. Features of mass flow meters: The output signal is directly proportional only to the mass flow rate, and is independent of the physical properties of the fluid (such as temperature, pressure, viscosity, density, Reynolds number, etc.) ； Remote transmission and control can be achieved by simply detecting and processing one signal (i.e., the instrument’s output signal) ； Only one variable is needed to integrate over time, so the accumulation of flow rate is simple, and so on.