Product Category

Thermal mass air flow meter

Thermal mass air flow meter

  • Gas Turbine Flow Meter

    Gas Turbine Flow Meter

    Robust Gas flow meter for natural gas,LPG,biogas flow measurement.Inquiry Gas TUF Flowmeter price with EVC directly from...

  • Vortex air flow meter

    Vortex air flow meter

    The vortex air flow meter has no movingparts as it works by the natural formation of vortices in the air stream. Itopera...

Thermal Mass Flowmeters (TMF for short), originated in the United States, are generally used in gas and air measurement in environments with high accuracy requirements, trade settlement, or difficult-to-measure environments. Compared with traditional air measuring instruments, thermal mass flow meters are widely used in various industries such as thermoelectricity, chemical industry, oil and gas, etc. due to their many advantages in gas and air measurement accuracy and maintenance.

Working principle of thermal mass air flow meter

How does a mass air flow meter work ?
Thermal mass air flow meter consists of a transmitter and a sensor, where the sensor is a temperature probe made of two platinum thermal resistors, two probes are placed in the air pipeline, one platinum thermal resistance is heated, and the other is sensed process temperature. When the air density remains unchanged, the air flow rate increases, the heated platinum thermal resistor cools faster, and the temperature difference between the two platinum thermal resistors decreases rapidly. When the air in the pipeline has no flow, the temperature difference reaches the maximum.

The temperature difference in the sensor can be converted into a DC voltage signal through the control circuit, and finally the 4-20 mA current is output at the output terminal, and the measured mass flow can be obtained from the on-site setting calculation circuit of the transmitter. Thermal Dispersion Technology provides a measuring instrument that can easily configure the signal output, while the display signal can be adjusted on-site using the built-in keyboard or a communicator.

Main features of thermal mass flow meters

Advantages of thermal mass flow meter for air
  • (1) It is easy to install and has various structures. There are two types of installation: insertion thermal mass air flow meter and pipeline type. It is easy to disassemble and easy to use. It can be used in high temperature air measurement occasions and corrosive environments.
  • (2) There are no moving parts, which reduces the measurement error caused by the dirty air or the blockage of the medium particles. The integrated design is adopted, and there is no need to add additional instruments, which reduces the difficulty of maintenance, and will not be affected by the leakage of the air.
  • (3) A platinum RTD sensor is used, and two RTDs are used in the sensor to balance the mass, so that it can accurately measure the mass flow of the air when the temperature, pressure, density, etc. change.
  • (4) High accuracy, high repeatability, no need for temperature and pressure compensation, the air mass flow is directly measured without temperature and pressure compensation, the accuracy can reach ±1% FS repeatability is generally about 0.05%, it is high accuracy air mass flow meter.
  • (5) It is more sensitive to low air flow measurement, with strong overload capacity and large range ratio. When the actual flow rate is much higher than the full range, a corresponding alarm will be made and the instrument will not be damaged, it can be used at low pressure air flow measurement.
  • (6) Thermal mass air flow meter cost is not very high ,especially for large pipelines air lines or ducts, such as 8 inch, 10”, 20”.,etc ,insertion thermal mass air flow meter is an economical solution for compressed air or air measurement.

Disadvantages of thermal mass flow meters

(1) If there is liquid in the pipeline, or the medium contains other impurities, it will cause air measurement errors.
(2) If the mixed air is measured and the gas composition changes, the internal parameters need to be recalculated and set according to the dynamic curve. If the gas composition is unstable, there will be errors in the measurement.

Measurement of acid gas by insertion thermal mass flow meter

The wear-resistant and anti-pollution characteristics of thermal mass flow meters make it useful in highly corrosive environments, improving the accuracy and feasibility of measuring acid mixtures. Insertion flow meters combine unique mass thermal dispersion sensing element, precise electronics, and rigorous fluid calibration in a rugged industrial package, making it an ideal air measurement instrument. The insertion air flow sensor can be installed and maintained online, but the sensor must be installed on the valve and inserted into the center of the pipe, otherwise it will cause measurement errors. The measurement principle of the flow meter is to convert the heat taken away by the measured medium into flow. When the measured air is not transported in the pipeline, the air will still take away part of the heat, resulting in a small amount of false flow when no medium passes through the pipeline. At this time, a small signal can be used to cut off about 5%.


In the past ten years, thermal mass air flowmeters have been continuously innovating in combination with modern microelectronics new technologies and new processes. With their unique characteristics, SILVER thermal mass air flow meters can measure acid gas, fuel gas, purified air, compressed air, flue air, blower air flow measurement, hydrogen and other single gases or Mixed gas, quickly in industrial production, successfully applied in measurement conditions and environments that other flow meters are incapable of.
Leave a Message Email Us

we will contact you within 24 hours. Protection Status