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Sharoten Industrial Technology (Shanghai) Co., Ltd
Working principle and characteristics of gas mass flowmeter
Date: 2025-06-17Read: 26
The gas mass flowmeter directly measures the mass flow rate of gas without temperature and pressure compensation. Its core working principle and application areas are as follows:
1、 Working principle
1. Thermal principle
Constant temperature difference method: The sensor contains two platinum thermistors, one heated to a constant temperature difference (speed sensor), and the other detecting gas temperature. The increase in current required to maintain a temperature difference is proportional to the mass flow rate as gas carries away heat.
Constant power method: Maintain a constant heating power and calculate the mass flow rate by measuring the temperature difference combined with the specific heat capacity of the gas at constant pressure.
Applicability: Suitable for low flow rate and small tube diameter scenarios (such as semiconductor manufacturing and laboratory microfluidic testing).
2. Coriolis principle
When gas flows through a high-frequency vibrating measuring tube, Coriolis force is generated, resulting in phase shift of the pipeline, which is proportional to the mass flow rate.
Advantages: High precision, not affected by gas properties (density, viscosity).
Limitations: High cost, large size, suitable for high-precision demand scenarios.
2、 Application Fields
1. Industrial Process Control
Energy and chemical industry: natural gas trade settlement, chemical plant reaction gas ratio, ammonia flow monitoring.
Metallurgy and Electric Power: Measurement of Blast Furnace Gas, Control of Boiler Gas/Air Supply.
2. High precision and special scenarios
Semiconductor manufacturing: precise control of process gases such as etching gas and deposition gas.
Environmental monitoring: Measurement of flue gas emissions and recycling of biogas.
Laboratory research and development: microfluidic gas experiments, fluid dynamics research.
3. Management of Public Facilities
Gas distribution metering, pipeline gas leak detection, and gas injection control in water treatment.
3、 Core advantages
1. Direct output of mass flow rate: avoids density conversion and temperature pressure compensation required for volumetric flow meters.
2. High adaptability: Suitable for complex environments with corrosive gases, mixed gases, and fluctuating working conditions.
3. Wide range ratio: Some thermal flow meters can cover a flow range from low to high speed.
4、 Selection key
1. Gas characteristics: cleanliness, corrosiveness, specific heat capacity.
2. Operating parameters: pipe diameter size, flow range, temperature/pressure limit.
Tip: In corrosive gas or wide temperature and pressure fluctuation scenarios, thermal flow meters need to be calibrated according to the gas, while Coriolis flow meters are more suitable for high-precision trade settlement.
