thermal mass flow meters working principle

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whatsapp: 008618049841995

thermal mass flow meter working principle

The working principle of thermal mass flowmeters (TMF) is mainly based on the heat exchange relationship between the fluid and the heat 

source to measure the mass flow of the fluid. Specifically, its working principle can be divided into the following aspects:

Basic principle

The thermal mass flowmeter measures the mass flow of the fluid by using the temperature field change generated when the fluid passes 

through the external heat source to heat the pipeline, or by the relationship between the energy required for the fluid temperature to rise 

and the mass of the fluid when the fluid is heated. This flowmeter is mainly used to measure the mass flow of gas and is popular for its

 high accuracy, high repeatability and high reliability.

Specific implementation method

The thermal mass flowmeter usually contains two key components: a heater and a temperature sensor. These two components are placed

 in the pipeline through which the fluid flows to measure the temperature and flow rate of the fluid.

Constant temperature difference method:

Sensor structure: The sensor part consists of two reference-level thermal resistors (such as platinum resistance temperature sensors), one 

as a heater (also called a velocity sensor) and the other as a temperature sensor.

Working principle: The heater is heated to a temperature higher than the fluid temperature, and the temperature sensor measures the

 temperature of the fluid. To maintain a constant temperature difference (ΔT) between the heater and the fluid, the control system adjusts 

the power of the heater. When the fluid flows through the pipe, it removes some of the heat from the heater, causing the temperature of

 the heater to drop. To keep the temperature difference constant, the control system increases the current supplied to the heater to

 compensate for the heat removed by the fluid. The faster the fluid flows, the more heat is removed, so the more current needs to be

 increased. This increase in current is proportional to the mass flow rate of the fluid, thus enabling the measurement of the fluid flow rate.

Advantages and Applications

Advantages:

Low pressure loss: Since the flow state of the fluid does not need to be changed during the measurement process, the pressure loss

 is small.

Wide flow range: Able to measure flow ranges from very low to very high.

High accuracy, high repeatability and high reliability: High-precision flow measurement is achieved through accurate heat measurement 

and control systems.

No moving parts: Long service life and low maintenance costs.

Can be used for extremely low gas flow monitoring and control: Especially suitable for occasions where accurate control of gas flow is

 required.

Applications:

Gas flow measurement in industrial fields such as steel mills and coking plants.

Boiler air flow measurement and secondary air volume monitoring.

Fluid flow measurement in chemical, petroleum, pharmaceutical, food and other industries.

Monitoring of sampled gas volume on analytical instruments such as gas chromatographs and gas analyzers.

If you want to know how to select thermal mass flow meter and how to get a quote, please contact CIXIFM winny:

Email: sales01@cxflowmeter.com

whatsapp: 008618049841995