Thermal Mass Flow Meters are manufactured mainly in the Western world. These flow meters are mainly used for the flow measurement of a variety of gases and are often called Gas Flow Meters. Manas Microsystems is one of India’s largest Gas Flow Meter manufacturers and exporters. We are perhaps the only Gas Flow Meter supplier with the capability to Manufacture, Assemble, Test, and calibrate mass flow meters for gas applications. Designed for accuracy and reliability, our gas flow meters are suitable for various industrial applications. Some of the potential export areas for these Gas Flow Meters include Southeast Asia (SEA), the Middle East, and Africa (MEA) regions. How does a Thermal Mass Flow Meter work? Whenever a fluid of a certain temperature is passed over any substance hotter than the fluid, the heat of the hot substance is taken away because of forced convection by the fluid, and the temperature of that substance drops. This fall in temperature is related to the mass flow of the fluid passing over the substance. If one can measure the amount of heat taken away by the flowing fluid one can calculate the mass flow rate. Where are Thermal Mass Flow Meters used? Some of the applications of Thermal Mass Flow Meters include Compressed Air in various industries, Oxygen Generators, and other compressed gases, flow measurement of gases like CNG, PNG, LNG, LPG, Biogas, Nitrogen, etc. Being a direct mass flow meter, it does not require any pressure and temperature compensation.

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Working of Thermal Mass
Flow Meters

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Thermal Mass Flow Meters Types
and Theory of Operations

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Working of a Thermal Mass Flow
Meter
Thermal mass flow meters, also known as thermal
dispersion or immersible mass flow meters, are used
to measure the total mass flow rate of a fluid,
primarily gases, flowing through closed conduits. It is
a direct measurement type mass flow meter with no
moving parts.

4. Theory of Operation
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Temperature Sensors
A thermal mass flow meter consists of two Platinum RTD temperature sensors for
this purpose. One sensor measures the current fluid temperature as a reference.
The second sensor is heated and has a constant temperature differential relative to
the first sensor.
Direct Mass Flow Measurement
When the flow of air/gas starts heat is taken away from the warmer sensor. The amount
of heat taken away is having a direct relation with the mass velocity of the fluid.
No Pressure or Temperature Compensation Needed
Due to its direct mass flow measurement capabilities, thermal mass flow meters
eliminate the need for pressure or temperature compensation.
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Types of a Thermal Mass Flow Meter
Thermal Dispersion / Immersible Type
In the case of Thermal dispersion or
immersible type, the heat is transferred to the
layer of the flowing fluid encountering the
heater surface. The heat transferred from the
surface of the heating element is related to
the point mass velocity of the fluid.

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Types of a Thermal Mass Flow Meter
Capillary Tube Type
In the second type, i.e., the capillary-type thermal
mass flow meter, the heat is transferred to the bulk
of fluid passing through the small, heated capillary
tube.
Although the principles of operation of both types
depend on heat convection, both methods are quite
different. Thermal dispersion flow meters are
commonly used for general industrial gas flow
applications in pipes and ducts and, hence, are more
popular for such industrial applications. The capillary
types are primarily used for smaller flows of clean
gases or liquids in tubes.

7. Applications of Thermal Mass Flow
Meters
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1 Compressed Air/Gas
Consumption Measurement
Used to measure the consumption of
compressed air or gas in various
industrial processes.
3 Industrial Oxygen Flow
Measurement
Utilized for precise measurement of
industrial oxygen flow.
2 Fuel Gases Consumption
Measurement
Applied in the flow measurement of fuel
gases like CNG, PNG, and LPG
consumption.
4 Biogas Measurement
Used in biogas plants for flow
measurement of Biogas at different
locatios.

8. Applications of Thermal Mass Flow
Meters
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Very Low-Pressure Conditions
Useful for applications involving very
low-pressure flowing conditions.
These meters can provide accurate
gas measurement even in such
conditions.
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Automobile Gas Engine Testing
Utilized in measuring CNG flow during
automobile engine testing.
6 Furnace and Burner Control
Applied in the precise control of furnaces
and burners in industrial processes.
Precise control can increase efficiency of
these processes and reduce energy
wastage.

9. Special Characteristics
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No Moving Parts
Due to the direct method of mass flow
measurement, thermal mass flow meters
do not contain any moving parts,
ensuring high reliability and minimal
maintenance requirements.
Precise Measurement
These meters are known for providing
precise gas flow measurement in various
industrial applications.

10. Advantages of Thermal Mass Flow
Meters
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Accurate and Reliable
These meters are known for their
accuracy and reliability in measuring
mass flow of gases in diverse industrial
settings.
Minimal Maintenance
These meters require minimal
maintenance due to the absence of
moving parts.

11. Conclusion
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Precision Measurement
Thermal mass flow meters offer highly accurate and precise
measurement of gas flow in variety of process conditions in
industrial processes.
Reliable Performance
These are renowned for their reliability even in challenging
industrial environments.
Low Maintenance
These require minimal maintenance due to their robust and efficient design.
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Maharashtra, India.
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Mob: +91 77220 34924 / 74200 99054
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