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Hi, I’m your industrial control assistant. Every day, I’ll share a little tip on industrial control technology – let’s learn together!* Today, what we are going to learn is related to mass flow meters. Mass flow meters were developed in the 1970s, and worldwide they represent an important tool for dynamic measurement. In the trade settlements of the petrochemical industry, mass flow meters play a crucial role. So, do you know how mass flow meters work? Let’s take a closer look. A mass flow meter is a measuring instrument that can accurately and directly measure the mass flow rate of fluid in closed pipelines. Its working principle is simple. The principle behind mass measurement in a Coriolis mass flow meter is Newton’s second law, F=Ma. When fluid flows through the vibrating tube, a Coriolis force is generated that is proportional to the mass flow rate. When no fluid is flowing, the vibrating tube does not twist, and the signals detected by the electromagnetic sensors on either side of the tube are in the same phase ； When fluid flows through, the vibrating tube twists under the action of torque, resulting in a phase difference between the two detectors. The transmitter measures the delay time between the signals from the left and right detectors; by multiplying this time difference by a flow calibration coefficient, the mass flow rate can be determined. The principle behind density measurement in a Coriolis mass flow meter is that the vibration frequency is inversely proportional to the square root of the fluid density; the fluid density is determined by measuring this vibration frequency. Therefore, a mass flow meter can measure both the mass flow rate of a fluid and its density. Advantages of mass flow meters: 1. Mass flow meters have a relatively high range; generally, it can reach a ratio of 20:1 to 50:1, and some instruments even have a range of over 100:1 ； 2. Mass flow meters that can perform accurate direct measurement of flow rate, featuring high measurement precision and good stability ； 3. It can be used with a wide range of media; mass flow meters are suitable for measuring dirty natural gas ； 4. The mass flow meter can be effectively maintained and cleaned, thereby extending its service life further ； 5. Mass flow meters are particularly suitable for process control applications involving trade handover measurements. Disadvantages of mass flow meters: 1. High price: For users accustomed to using rotameters, mass flow meters indeed appear to be more expensive. 2. High maintenance costs: In principle, measuring devices should be calibrated regularly ； Although the failure rate of products varies among different brands, the possibility of failures exists in all cases; therefore, calibration and repair costs are generally required. Due to different charging policies among manufacturers, varying usage patterns by users, and differences in product failure rates, users’ maintenance costs may vary. 3. High production difficulty: Mass flow meters/mass flow controllers are high-tech products, and their production is quite challenging. This is one of the reasons why many people in China have tried to develop them over the years, yet few have been successful. Due to the high difficulties in production, it is also hard to ensure quality; therefore, users should be cautious when making purchases to avoid endless troubles. 4. In some cases, it may cause blockages in the gas path: Faults in the mass flow controller, contamination of the gas supply that leads to blockages in the sensors or dividers, or operational errors can all result in blockages in the gas path. For some users, special attention should be paid to selecting the appropriate model, as well as to proper system design and correct usage. That’s all for today’s content. If there’s anything else you’d like to know, feel free to leave a message. New updates will be posted regularly, so please stay tuned.