Thermal Gas Mass Flowmeter

The thermal gas mass flowmeter is designed on the basis of thermal dispersion and adopts the method of constant differential temperature to measuring gas flow. It has advantages of small size, easy installation, high reliability, and high accuracy, etc. They feature all-welded, no moving parts, direct mass flow sensors, suitable for dirty, corrosive, low flow applications that conventional flow technologies struggle with.

It has the following distinguishing advantages:

  • Gas mass meters calculate mass flow rather than volumetric flow. They do not require temperature or pressure correction, which means there is no additional expense for purchasing and installing other equipment
  • Thermal flowmeters provide excellent accuracy and repeatability over a wide range of flow rates.
  • Thermal flow meters can measure flow in large pipes
  • Easy installation and maintenance. If the conditions on site are permissible, the meter can achieve a hot-tapped installation and maintenance. (Special order of custom-made)
  • Able to measure accurately low gas flow rates or low gas velocities
  • Thermal flow meters have no moving parts, which reduces maintenance and permits the use in demanding application areas, including saturated gas
  • It does not require a correction for changes in gas temperature, pressure, viscosity and density

Working Principle

The meter contains two platinum resistance temperature sensors. The thermal principle operates by monitoring the cooling effect of a gas stream as it passes over a heated sensor. Gas flowing through the sensing section passes over two sensors one of which is used conventionally as a temperature sensor, whilst the other is used as a heater. The temperature sensor monitors the actual process values whilst the heater is maintained at a constant differential temperature above this by varying the power consumed by the sensor. The greater the gas velocity, the greater the cooling effect and power required to maintain the differential temperature. The measured heater power is therefore a measure of the gas mass flow rate

Key Feature

  • Wide range: 0.5Nm/s～100Nm/s for gas. The meter also can be used for gas leak detection
  • Configuring with RS485 or HART interface to realize factory automation and integration
  • Digital design, high accuracy and stability
  • Measuring the mass flow or volume flow of gas
  • Do not need to do temperature and pressure compensation in principle with accurate measurement and easy operation
  • Good vibration resistance and long service life. No moving parts and pressure sensor in transducer, no vibration influence on the measurement accuracy
  • Digital design, high accuracy and stability

Application Range

Thermal mass flow meters are suitable for a variety of processes requiring mass flow measurement and are frequently used for the regulation of low gas flows. Some common gas flow applications for thermal mass flow meters include

  • Compressed air flow and distribution
  • Natural gas consumption eg for burner and boiler feed control
  • Monitoring and control of stack or flue gas (where composition known)
  • Landfill gas recovery
  • Flare gas measurement
  • Gas flow mixing & blending
  • Gas leak testing and detection
  • Gas leak testing and detection

Technical Specification