Thermal mass flow transmitter

The thermal mass flow transmitter, based on thermal dispersion technology, provides reliable mass measurement for air and gas flow applications. The powerful, yet easy-to-use, electronics are contained in a compact explosion-proof enclosure.

The flowmeter is available with both insertion probes, as well as flow body design for smaller pipe sizes. It offers excellent performance at an exceptional value.

Operating Principle:

The mass flow transmitter measures mass flow by detecting heat dissipation from a heat surface. The sensor contains two mass balanced elements with precision matched RTDs.

The reference sensor measures the process temperature (up to +400°F [+200°C]); the second RTD measures the temperature of the heated sensor. The power to the heater is varied to maintain a constant temperature difference above the reference temperature.

There is an inherent non-linear relationship between power and mass flow. The microprocessor compares the power against the calibration curve and converts the power requirements to the mass flow rate. Temperature is also measured to provide temperature compensation of the mass flow over the operating range of the instrument.

Applications :

  • Compressed air, combustion air
  • Natural gas
  • Aeration air
  • Digester / biogas
  • Vent Lines / Flare Headers
  • Hydrogen lines


  • Direct mass flow measurement of air and gas
  • Excellent low flow sensitivity
  • Process temperatures to +400°F (+200°C)
  • Rotable housing
  • FM / FMc / ATEX / IEC approvals
  • Resettable and non-resettable totalizers
  • Calibration verification in the field
  • Remote electronics, in option