
The core methods for calibrating thermal mass flow meters are divided into three categories, which are suitable for different scenarios: real flow calibration method is accurate but costly, dry calibration method is convenient but slightly less accurate, and comparative calibration method requires serial standard equipment. 1. Real flow calibration method (accuracy priority scenario) uses actual fluid (such as gas) in conjunction with a standard calibration device to compare the measured flow meter data with known flow values, and the error value directly reflects the calibration result. This method requires a laboratory level flow standard device, which is commonly used in measurement certification, high-precision industrial production, and other scenarios. However, the equipment investment and site requirements are high. Dry calibration method (rapid on-site detection) is based on the mathematical model of the sensor provided by the manufacturer, inputting parameters such as fluid type, temperature, pressure, etc., and simulating flow output through theoretical calculations. Suitable for daily maintenance or on-site testing without actual flow conditions, it is easy to operate and cost-effective, but relies on the accuracy of equipment factory parameters. Drift errors may occur after long-term use.
3. Comparative calibration method (series comparison verification) installs the flow meter to be calibrated in series with a certified standard flow meter, synchronously measures the flow data of the same pipeline, and compares the differences. This method is suitable for online calibration or environments with mature flow systems, but standard flow meters must be regularly calibrated, and the installation positions of the two meters must meet the requirements of flow stability. After understanding the logic of selecting calibration methods, it is necessary to confirm whether the fluid properties parameters (such as gas composition, viscosity), temperature and pressure range are consistent with the calibration conditions before operation, in order to avoid calibration failure due to differences in operating conditions.
Thermal gas mass flowmeter works based on the