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Mass flow meter is a precision and novel instrument - focus on microfluidic control technology

In the flow metering industry, the mass flow meter generally measures the mass flow of the fluid medium directly without compensation by other parameters. The most remarkable feature of the mass flow meter is that it can directly measure the mass flow rate of the medium, without being affected by factors such as pressure and temperature of the working state of the medium.
At present, mass flow is also calculated as a kind of mass flow meter in the industry. It features a pressure and temperature sensor while the flow sensor is working. The measured mass flow parameters are compensated by the parameters of the medium density as a function of temperature and pressure, thereby indirectly measuring the mass flow rate of the medium. Because the mass flow meter needs a complete and accurate compensation system, the whole set of instruments is complicated. There are also many factors that cause measurement errors. Therefore, indirect mass flow meters are being replaced by mass flow meters in many applications.
The mass flow meter is a novel instrument that directly and precisely measures the mass flow of the fluid. The two main tubes of the structure are made of two U-shaped tubes side by side, so that the bent portions of the two tubes vibrate in opposite directions, and the straight tubes on both sides will Following the vibration, that is, they will be close together or open at the same time, that is, the vibration of the two tubes is synchronous and symmetrical.
Flow meter made by the principle of mass flow meter. When the mass flow meter is working, the measuring tube is required to generate a vibration of a fixed frequency to simulate the rotation of the measuring tube along the axis of the pipeline, thereby generating a Coriolis force to achieve the purpose of measuring the flow. The frequency of this vibration is the natural frequency of the measuring tube structural system. The magnitude of the vibration frequency varies depending on the structure and size, the mass, and the elastic modulus of the material, and its size ranges from several tens to several hundreds of hertz. Therefore, when the mass flow meter is working, if there is a vibration source at the installation site, it will interfere with the stability of its operation. Thereby, the metering error of the flow meter is increased. In particular, resonance occurs when the frequency of the interference vibration source approaches or coincides with the natural frequency of the measuring tube. Causes abnormal vibration of the flowmeter sensor. Make the sensor completely inoperable.
If the fluid is introduced into the tube while it is vibrating synchronously, causing it to flow forward along the tube, the tube will force the fluid to vibrate up and down with it. In order to resist this forced vibration, the fluid will give the tube a reaction force perpendicular to its flow direction. Under the action of the Coriolis effect force, the vibration of the tube is not synchronized, and the inlet and outlet sections are in the tube. There is a difference in the timing of the vibrations (the difference is due to the opposite of the fluid flow in the inlet and outlet sections), which is called the phase time difference. This difference is proportional to the amount of fluid mass flow through the tube. If the magnitude of this time difference can be detected by the circuit, the magnitude of the mass flow can be determined. The biggest difference between mass flow meters and dozens of conventional volumetric flow meters currently in use in the world is the mass of the mass measured, in units of kg/h. Flowmeters in mass (eg kilograms) are more accurate and constant than volumetric flowmeters in units of volume (eg, liters or cubic meters). Because the quality is in accordance with the law of conservation.

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