Factors affecting the accuracy of thermal gas mass flow meters

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　　Thermal mass flow meters are flow meters with a wide range of applications. Many users, when choosing such meters, are concerned about their accuracy, and they want to know what factors and issues affect this accuracy in practical use. In practical applications, the accuracy of thermal gas mass flow meters and the factors affecting that accuracy mainly include the following aspects. 　　1. The concept of accuracy 　Under normal operating conditions, the degree of accuracy of the measurements taken by an instrument is referred to as the instrument’s accuracy. *It is commonly called precision. 　　The accuracy of the thermal gas mass flow meter is: ±1% of the reading + ±0.5% of the full scale. 2. Influence of straight pipe sections: A lack of sufficient straight pipe sections affects the measurement accuracy, with different flow resistances having varying degrees of impact; by providing information on the flow resistance and the length of the straight pipe sections, it is possible to calculate the magnitude of the deviation. 　　3. Water, water vapor 　　If the medium being measured contains water or water vapor, the formation of water droplets on the probe can result in higher measurement values. The magnitude of the deviation is uncalculable. 　　4. Influence of insertion depth 　　During calibration, the sensor’s probe is positioned on the center line of the pipeline; if it deviates from this center line during actual installation, it will cause errors in the measurement values. The magnitude of the deviation is uncalculable. 　　5. Component changes 　　When the components of the medium being measured change, it will result in deviations in the measurement values. By providing the modified components, the magnitude of the deviation can be calculated. 　　6. Solutions 　For measurements involving media containing water or water vapor, it is recommended to use an installation method in which holes are made at a 45-degree angle sloping upward in the lower half of the horizontal pipe. 　　Considering the factors mentioned above, it is evident that in the operation of thermal gas mass flow meters, the operating environment has a significant impact on the performance of the device; moreover, a proper installation method is necessary to ensure that such meters maintain their accuracy. 　　As a highly precise instrument, a flow meter requires strict adherence to its specifications not only during manufacturing and use, but also requires special attention during maintenance in order to prevent it from reaching the end of its useful life prematurely.