Thermal mass Flow meter

Thermal mass flow meters, also known as thermal dispersion or immersible mass flow meters, comprise a family of instruments for the measurement of the total mass flow rate of a fluid, primarily gases, flowing through closed conduits. Furthermore, a thermal mass flow meter can be built by measuring temperature differential across a silicon-based MEMS chip.Both types measure fluid mass flow rate by means of the heat convected from a heated surface to the flowing fluid.

Thermal mass flow meter Overview

Thermal mass flow meters are designed to accurately monitor and measure mass flow (as opposed to measuring volumetric flow) of clean gases, a parameter that is not temperature-dependent.

Therefore, the thermal mass flow meter does not require a correction for changes in gas temperature, pressure, viscosity, and density.

Thermal mass flow meter Principle

Thermal mass flow meters employ the thermal dispersion principle whereby the rate of heat absorbed by a fluid flowing in a pipe or duct is directly proportional to its mass flow. In a typical thermal flow meter gas flowing over a source of heat absorbs the heat and cools the source.

As flow increases, more heat is absorbed by the gas. The amount of heat dissipated from the heat source is proportional to the gas mass flow and its thermal properties. Therefore, measurement of the heat transfer supplies data from which a mass flow rate may be calculated.



Mass & Volumetric flow monitoring of most clean gas

  • The foremost advantage is fixed parts
  • Withstands changes in density, viscosity, temperature, and pressure
  • Not affected by changes in gas volume
  • Easy to maintain with a low maintenance cost
  • Capable of operating in both directions

Easy to Install, lots of field installation options

Rugged, long-lasting design for the toughest applications


Pipe diameter:3/4″inch to 80″inch



Pressure rate:≤16 Bar,≤25 Bar,≤40 Bar

Temperature:≤250℃(Normal),≤350℃(High temperature)


Ambient temperature:
Operating: -20° to 60°C
Storage: -40° to 65°C


Power supply:90-250VAC,24VDC 500mA

Output signal:

  • 4-20mA
  • Pulse
  • User-definable pulse output for totalized flow

Digital communications: RS485, Hart

Hazardous-Area Location Enclosure


Wafer type

Insertion TYPE

Inline type

Remote Indicator



  • inline Thermal mass Flow meter 1“ inch drawing
  • inline Thermal mass Flow meter 1.5“ inch drawing


  • RS485 Protocol
  • Hart Protocol

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