Learn about 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, inaccuracies in measurement often occur. Measurement principle of mass flow meters Mass flow meters use a heat-sensitive measurement method to determine the flow rate by assessing the mass of molecules carried away by the flow. Since this heat-sensitive measurement approach is employed, changes in gas temperature or pressure do not affect the measurement results. A mass flow meter is a relatively accurate, fast, reliable, efficient, stable, and flexible flow measurement instrument. It will find wider application in fields such as petroleum processing and the chemical industry, and it is believed to hold great potential for advancing flow measurement technologies. A mass flow meter cannot control the flow rate; it can only measure the mass flow of liquids or gases, and outputs the flow value through an analog voltage, current, or serial communication. However, a mass flow controller is a device that can both detect and control. In addition to the measuring component, the mass flow controller itself is equipped with an electromagnetic control valve or a piezoelectric valve, thereby enabling the mass flow control to function as a closed-loop system for regulating the mass flow rate of the fluid. The setpoint of the mass flow controller can be provided via an analog voltage, an analog current, or a computer or PLC. The working principle of a mass flow meter is simple: it relies on the behavior of fluid flow within a closed pipeline – whether in linear motion or rotational motion – which generates a force proportional to the mass flow rate; instruments for measurement are designed 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. Function of a mass flow meter A mass flow meter directly measures the mass flow rate of the fluid passing through it; it can also measure the density of the fluid and, indirectly, its temperature. Since the transmitter is an intelligent instrument based on a microcontroller, more than a dozen parameters can be derived from these three basic quantities for use by users. The mass flow meter features flexible configuration, powerful functions, and a high performance-to-price ratio, making it a next-generation flow meter. A flow measuring instrument for measuring the mass flow rate in a pipeline. When the fluid under test experiences significant changes in parameters such as pressure and temperature, measuring only the volumetric flow rate can result in large measurement errors due to changes in the fluid density. In positive-displacement and differential-pressure flowmeters, the density of the fluid being measured can vary by 30%, which can result in a flow measurement error of 30–40%. With the increase in automation levels, many production processes have put forward new requirements for flow measurement. The chemical reaction process is controlled by the quality of the reactants (rather than their volume). The heating and cooling effects of steam and air currents are also proportional to the mass flow rate. Strict control over product quality, accurate cost accounting, and fuel quantity management for aircraft and missiles all require precision as well. Therefore, a mass flow meter is an important flow measurement instrument. The advantages of mass flow meters mainly include the following aspects: First, mass flow meters have a relatively high range, typically ranging from 20:1 to 50:1; in some cases, the range can exceed 100:1 ； Secondly, there are mass flow meters that can effectively measure flow rates directly; they feature high measurement accuracy as well as good stability ； Thirdly, it can use a wide range of media; mass flow meters are suitable for measuring dirty natural gas ； Fourth, mass flow meters can be effectively maintained and cleaned to ensure an extended service life ； Fifth, mass flow meters are particularly suitable for process control applications involving trade handover measurements. At present, Kepan has independently developed dozens of products, including experimental electric furnaces, CVD gas supply systems, plasma cleaners, small-scale ion sputtering devices, and small-scale evaporation coating machines. These products are mainly used by research institutions and universities, as well as industrial and mining enterprises, for studying the physical and chemical properties of new materials and new energy sources. They are widely sold to various universities and material research institutes. In summary, a mass flow meter is a measuring instrument that can effectively and accurately measure the mass flow rate of fluid in closed pipelines.