Thermal Mass Flow Meter

$ 2,187.50$ 6,000.00

A Thermal Mass Flowmeter works by measuring the total mass flow rate of a fluid flowing through a pipe or duct.  In a thermal flowmeter’s simplest working configuration, fluid flows past a heated thermal sensor and a temperature sensor.  As the molecules of the fluid flow past the heated thermal sensor, heat is lost to the flowing fluid.

Thermal mass flow meter, 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.  A second type is the capillary-tube type of thermal mass flow meter.  Many mass flow controllers (MFC) which combine a mass flow meter, electronics and a valve are based on this design.  Furthermore, a thermal mass flow meter can be built by measuring temperature differential across a silicon-based MEMS chip.


in.A Thermal Mass Flow Meter is suitable for all industrial and test platform applications that require fast, accurate gas measurement.  Moreover, the flowmeter directly indicates the mass flow or standardized volume flow of the gas without any additional pressure and temperature compensation.  Additionally, they have impressive high accuracy, short response times, and a very wide flow range, with almost no loss of accuracy even at the lowest flow.

A thermal mass flowmeter is an instrument used to measure the flow rate of a fluid, such as gases or liquids, by utilizing the principle of thermal conduction. It is widely used in various industries, including chemical, oil and gas, pharmaceutical, and food and beverage, because of its accuracy, reliability, and versatility.

Working Principle of a Thermal Mass Flow Meter

The basic working principle of a thermal mass flow meter involves the measurement of the cooling effect of a flowing fluid on a heated sensor element.  The sensor element consists of two temperature sensors: a heated sensor and a reference sensor.  The heated sensor is maintained at a constant temperature higher than the fluid temperature, while the reference sensor is kept at the fluid temperature.  As the fluid flows through the flowmeter, it conducts heat away from the heated sensor, resulting in a temperature difference between the two sensors.

The magnitude of this temperature difference is directly proportional to the mass flow rate of the fluid.  The thermal mass flow meter measures this temperature difference and calculates the mass flow rate using a heat transfer equation.  By measuring the thermal conductivity and specific heat capacity of the fluid, the flowmeter provides an accurate measurement of the mass flow rate.

Different Types of a Thermal Mass Flow Meter

There are different types of thermal mass flowmeters available in the market. One common design is the insertion type flowmeter, where the sensor element is inserted into the flow stream through a probe. This type of flowmeter is suitable for large pipe sizes and high flow rates.

Another design is the inline type flowmeter, where the sensor element is directly installed in the flow line. This type of flowmeter is compact, easy to install, and suitable for a wide range of pipe sizes. It is commonly used for measuring gases and compressed air.
Thermal mass flowmeters offer several advantages over other flow measurement technologies. Firstly, they have no moving parts, which means they are less prone to mechanical wear, reducing maintenance requirements. Secondly, they have a wide turndown ratio, allowing accurate measurements over a broad range of flow rates.


Additionally, they have a fast response time, enabling real-time measurement and control.
Thermal mass flowmeters also have some limitations that need to be considered. They are generally not suitable for measuring fluids with high viscosity or low thermal conductivity, as they may affect the accuracy of the measurement. Furthermore, they are sensitive to changes in fluid composition, so it is important to ensure that the fluid characteristics are within the flowmeter’s specified range.

In conclusion, a thermal mass flowmeter is a versatile instrument used to measure the flow rate of fluids in various industries.  Its principle of operation based on thermal conduction provides accurate and reliable measurements.  With no moving parts, wide turndown ratio, and fast response time, thermal mass flowmeters are an ideal choice for applications requiring precise and real-time flow measurement.


Thermal mass flowmeters are commonly used in a variety of applications where accurate and reliable flow measurements are required.  Some of the key industries that extensively utilize thermal mass flowmeters include:

Chemical Industry

In chemical manufacturing processes, thermal mass flowmeters are used for measuring the flow rates of various gases and liquids.  They play a crucial role in controlling and optimizing the dosing of chemicals, maintaining consistent production quality, and ensuring safe operations.

Oil and Gas Industry

mass flowmeters are widely employed in the oil and gas sector for monitoring gas flows in pipelines, measuring flare gas emissions, quantifying fuel consumption, and controlling the distribution of natural gas.  They help in detecting leakages, optimizing energy usage, and ensuring compliance with environmental regulations.

Pharmaceutical Industry

In pharmaceutical production, precise measurement of different gases and liquids is vital for the success of manufacturing processes.  Thermal mass flowmeters are used for monitoring and controlling the flow of compressed air, nitrogen, carbon dioxide, and other process gases, ensuring efficiency and quality in pharmaceutical operations.

Food and Beverage Industry

Thermal mass flowmeters find application in the food and beverage sector for measuring the flow rates of gases such as carbon dioxide used in carbonation processes, as well as for monitoring the flow of liquids like water, milk, fruit juices, and beverages.  Accurate flow measurement is essential to control ingredient proportions and maintain product consistency.

HVAC and Building Automation

Heating, ventilation, and air conditioning (HVAC) systems rely on thermal mass flowmeters for measuring the flow of air and other gases.  These flowmeters help in optimizing energy consumption, monitoring indoor air quality, and regulating temperature and humidity levels in commercial and residential buildings.

Environmental Monitoring

Thermal mass flowmeters play a role in environmental monitoring applications, such as measuring gas emissions from industrial processes, stack gases, or exhaust gases from vehicles.  They assist in determining compliance with emission regulations and assessing air quality.

It is important to note that the specific design and features of thermal mass flowmeters can vary based on the application requirements.  Moreover, it factors such as fluid properties, desired measurement range, installation considerations.  Additionally, they have certifications for use in hazardous environments might influence the selection of a suitable thermal mass flowmeter.

Overall, thermal mass flowmeters have become an integral part of various industries, offering accurate and reliable flow measurements.  Their versatility, ease of installation, and low maintenance requirements make them an ideal choice for applications where precise flow control and monitoring are critical.

Features and Benefits

Wide Range of Applications

The Thermal mass flow meter can be deployed in a wide range of applications, including general process control, gas consumption monitoring, air and gas flow monitoring in HVAC systems, and environmental monitoring.

High Accuracy and Repeatability for a Thermal Mass Flow Meter

Thermal mass flow meters are known for their high level of accuracy and repeatability in measuring flow rates.  Moreover, this accuracy is maintained across a wide range of flow rates, making them reliable for both low and high flow conditions.

Multi-Fluid Capability

Many thermal mass flow meters are designed to measure the flow rates of different gases or liquids.  Additionally, they can be calibrated for specific fluid properties, allowing for accurate measurements across various fluids with different thermal conductivities and specific heat capacities.

Wide Turndown Ratio

The Thermal mass flow meter offer a wide turndown ratio, which means they can accurately measure flow rates from extremely low to very high velocities.  Also, this flexibility enables them to handle varying flow conditions without compromising measurement accuracy.

Real-Time Measurement and Response

Thermal mass flowmeters provide real-time flow rate measurements, allowing for immediate process adjustments and control. They have a fast response time, making them suitable for applications that require quick monitoring and adjustment.

Minimal Pressure Drop

Thermal mass flowmeters have a minimal pressure drop compared to other flow measurement technologies.  This ensures that the flow characteristics of the system being measured are not significantly affected.  Also, minimizing any potential disruption to the overall process.

Easy Installation and Maintenance

Thermal mass flowmeters are relatively simple to install and require minimal maintenance.  With no moving parts, there are fewer components that can wear or malfunction, reducing the need for regular maintenance and decreasing the risk of breakdowns.

Digital Communication and Integration

Many modern thermal mass flowmeters come equipped with digital communication protocols such as Modbus, HART, or Foundation Fieldbus.  This allows for seamless integration with control systems, enabling remote monitoring, data logging, and easy integration within an industrial network.

Compact and Lightweight Design

Thermal mass flowmeters are generally compact and lightweight, offering ease of installation.  Additionally, it adds flexibility in various piping systems or field locations.

Cost-Effective Solution

Thermal mass flowmeters are often considered a cost-effective flow measurement solution.  This is due to their accuracy, low maintenance requirements, and long-term reliability.  Their ability to provide precise flow measurements helps optimize processes.  This will reduce wastage, resulting in cost savings over time.

In summary, thermal mass flowmeters offer high accuracy, multi-fluid capability, and real-time flow rate measurement. With their wide turndown ratio, minimal pressure drop, easy installation, and digital communication capabilities.  Considering this, they provide a reliable and cost-effective solution for diverse flow measurement applications across different industries.


  • Direct measurement of gas mass flow without any temperature or pressure compensation
  • ± 1.0% high accuracy, fast response time, and very wide flow range.  In addition, even at the lower limit of the flow range, the accuracy is still very good.
  • Applications:  Industrial plants, oil, and gas upstream and downstream production, water and wastewater treatment plants, etc.

Product introduction

A Thermal Mass Flow Meter is suitable for all industrial and test rig applications that demand quick and precise gas measurement.  Also, the Flow Meters directly indicate the mass flow or normalized volume flow of gases.  This is without any additional pressure and temperature compensation.  Finally, they have impressively high accuracy, short response time, and a very wide flow range.  This happens with virtually no loss of accuracy even at the lowest flow rates.

Touch screen transmitter: 

We have our own patented touch screen transmitters with DSP core processor with faster data processing speed.

Insertion Type; Pipeline Type: 

For the pipeline size below DN65, it is recommended to use the pipeline type.  Moreover, while for the pipeline size higher than DN65, it is recommended to use the insertion type.


Also, 4-20mA, Standard RS 485 communication protocol, and HART Protocol


The connections can be customized, including flanges, threaded connections, etc.  Furthermore, we will also include the ball head along with the thermal flow meters.


We are providing the new generation of DSP transmitters with faster data processing.


Finally, the sensor of thermal mass flow meters includes two sensors.  While one is to heat the air, and the other one is to sense the heat took away by the flowing of air.

If you are looking for questions and answers?

Additional information

Weight 12 lbs
Dimensions 24 × 14 × 14 in

3/4", 1", 1-1/2", 2", 3", 4"

Pressure Class

150LB, 300LB, 600LB


NPT, Flanged, Triclamp


Yes, No


24 VDC, 120 VAC

Communication Protocol



4-20 MA, 0-10 VDC


Explosion Proof, Intrinsically Safe



Currently no product agency approvals.

Enclosure Certifications by manufacturer
US – CL. I. GR. A,B,C,D; CL. II. GR. E,F,G; CL. III.;TYPE 4X
IECEx – Ex d IIC Gb, Ex t IIIC Db,
ATEX – II 2G Ex IIC Gb, II 2Dd Ex t 111C Db

Linear signal output
0–5 VDC & 4–20 mA (Flow and Temperature)

Event Relay Rating one with Frequency or two, 1 Amp @ 30Vdc (33W)

Signal Interface
RS232 & RS485 Modbus RTU embedded, Optional HART or Profibus DP, LCD (flow rate, flow total, gas temperature)

Accuracy, including linearity (Ref.: 21°C)
±(1% of Reading + 0.5% of Full Scale + GTC)

±0.2% of Full Scale

Sensor response time
1 second to 63% of final value

Turn down ratio
100:1 @ 10 SFPM (.051 NMPS) Minimum Reading

Electronics PCB temperature range
-40° to 158°F (-40° to +70°C)

Environmental temperature range
-40° to 140°F (-40° to +60°C)

Gas temperature range
-40°–392°F (-40°–200°C)

Gas temperature coefficient (GTC)
0.02% Full Scale/°C

Gas pressure effect
Negligible over ± 20% of absolute calibration pressure

Pressure rating maximum
500 PSI Std.

Input power requirement
24VDC @ 250mA, 115 VAC 50/60 Hz optional, 230 VAC 50/60 Hz optional

Flow Transmitter power requirements
5 watts maximum

RAM Back-up
Lithium Battery

Wetted materials
316 Stainless Steel (Hastelloy optional)

Standard temperature & pressure (STP)
70°F & 29.92″ Hg (Air .075 lb./cubic foot)

NIST traceable calibration

NOTE: Specifications subject to change without notice.



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