Summary of experience in the application of mass flow meters

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Mass flow meters were developed in the 1970s. Worldwide, they represent an important method of dynamic measurement. In the trade settlements of the petrochemical industry, mass flow meters play a crucial role; their measurement errors not only affect the economic efficiency of enterprises but also help to ensure balance between the supply and demand of materials in various production facilities. However, in practical use, due to the fact that the structure, working principle, and operating conditions of mass flow meters are not well understood, issues with inaccurate measurement often arise. 　　 A mass flow meter is a measuring instrument that can accurately and directly measure the mass flow rate of fluid in closed pipelines. The working principle of a mass flow meter is simple: it relies on the behavior of fluid flow within a closed pipeline; whether the fluid moves in a straight line or in a rotational motion, a force that is proportional to the mass flow rate is generated, and instruments for measurement are created based on this principle. 　　Due to its unique and excellent properties, mass flow meters are being recognized and used by an increasing number of users, and they are now employed in many applications for measuring gas flow rates. However, there are also many problems and misconceptions in these applications. irresponsible marketing by various manufacturers, along with quality defects in the products, create numerous obstacles and challenges in their use. This has led to misunderstandings among many users regarding thermal gas mass flow meters; some believe blindly that such meters can measure gases under all operating conditions, while others reject and oppose them. Over the past few years, I have been dedicated to promoting and publicizing mass flowmeter products. I have come into contact with flowmeters from various domestic and international brands, and encountered many application-related issues during this promotion work; as a result, I have accumulated a large number of cases. By analyzing these cases, I have gained some insights of my own, which I would like to share with all of you. 　　. Structure of domestic mass flow meters: There are many brands of domestic mass flow meters, each with a different design, but in terms of the measurement principle their internal structure is essentially the same; they are all manufactured based on the principle of the Coriolis mass flow meter. The internal structure of a mass flow meter consists mainly of two parts: the measurement tube and the sensing element. The measurement tube is made up of two bends with identical diameters, through which the fluid flows ； The detection elements mainly consist of three coils (one drive coil and two detection coils) and a temperature sensor, which are distributed between the two measurement tubes. The drive coil generates periodic mechanical vibrations in the two measurement tubes through electromagnetic oscillation, while the two detection coils respectively detect the amplitude and frequency of these vibrations. Since the vibration of the measuring tube is affected by the weight of the liquid inside it, the mass of the liquid in the tube can be determined by measuring the changes in its vibration. This allows for the calculation of the instantaneous mass flow rate and density of the medium flowing through the mass flow meter. 　　Use of domestically produced mass flow meters: At the end of the last century, domestic instrument manufacturers did not fully master the technology for manufacturing mass flow meters. The mass flow meters in use in China were mainly imported brands, and their high prices meant they were used only for primary trade settlements. Due to the large number of such meters required for measuring the flow of materials in and out of production facilities, the procurement costs were beyond the reach of most companies. As a result, volumetric flow meters were commonly used in China for measuring the liquid flow in and out of production facilities. Positive displacement flowmeters measure the volume of liquid materials by relying on a fixed volume between a mechanical rotor and a chamber; this mechanical mechanism results in high failure rates and poor accuracy, making them unsuitable for the increasingly stringent measurement requirements within enterprises. 　　Entering the 21st century, domestic brand meters entered a period of rapid development. Thanks to the continuous research and development by manufacturers, many of them have mastered the key technologies and manufacturing processes related to mass flow meters. As a result, the performance of domestic mass flow meters has continued to improve. Their low cost gives them an advantage, allowing them to be used on a large scale for measuring the flow of materials in various devices within enterprises; they have thus become the preferred choice over volumetric flow meters.