Karman vortex air flow sensor is a commonly used flow meter for measuring air. Karman vortex air flow sensor is also called vortex shedding flow meter.

Karman vortex air flow sensor VS  Mass air flow sensor

There are many types of instruments that can be used to measure air, but the actual air flow rate used in the field is divided according to its principles, and there are not many types. Karman vortex air flow sensor and Mass air flow sensor are two commonly used.

Which one should you choose?

What is a Karman vortex air flow sensor?

Karman vortex air flow sensor is a volume flow meter.

Karman vortex air flow sensor uses airflow to bypass a cone and generate two rows of vortices downstream. The vortex frequency has a functional relationship with the intake air flow. An instrument that determines the air flow by detecting the frequency of the vortex by optical or ultrasonic methods.

Extended Reading: Digital air flow meters

What is a mass air flow sensor ?

The mass air flow sensor is a mass flow meter. Also called Thermal gas mass flow meters.

Thermal gas mass flow meters are instruments that use the principle of thermal diffusion to measure gas flow. The sensor is composed of two reference thermal resistance (RTD).

Thermal gas mass flow meter can measure air, nitrogen, carbon dioxide, methane, etc.
A single component or a mixture of certain components. The flowmeter is generally verified with ammonia or air as the medium when it leaves the factory.

Guess you like: Gas Mass Flow Meter

Karman vortex air flow sensor VS Mass air flow sensor

NameKarman vortexMass
AppearanceVortex Flow MetersThermal mass flowmeters
Measurement PrincipleThrough measuring frequency of
turbulences behind an obstacle to
reflect the velocity of the gas, so
measures the actual volume flow of
the gas .
Measures the mass flow of the gas
via measuring the energy
needed to keep a heated resistor
at a constant temperature.
Temperature and Pressure CompensationTo calculate the standard volumetric flow , need temperature and pressure compensation . ( Requires temperature and pressure measurement additionally )There is a fixed relationship
between standard flow and mass flow (Be determined by the density of gas under standard condition ) , no need the temperature and pressure compensation.
SensitivityNo response to the flow less than 4 m/s.Can measures the flow small to 0 m/s.
Measure Ranges4-75 m/s0-224 m/s
Main factors affecting measurement accuracyvibrate(a slight shaking can affect the measuring accuracy a lot)
The cleanliness of the measured gas (No long-term measurement behind the air compressor)
Repair and
Can not install or uninstall under pressure, high cost of repair or calibration.Can install or uninstall under pressure,low cost of repair or calibration.

Extended reading: Volumetric Flow Rate To Mass Flow Rate

Applicaitons :

The Karman vortex air flow sensor is widely used, gas, liquid, and steam can be measured.

The Mass air flow sensor can only measure gas;


Karman vortex air flow sensor is much cheaper;

Installation conditions:

The vortex flowmeter has requirements for the installation of the straight pipe section of the measuring pipeline, generally the first 10 and the back 5.

The thermal mass flow meter has no limitation.


  1. Thermal gas mass flow meters have the following technical advantages:

A true mass flow meter does not require temperature and pressure compensation for gas flow measurement. The measurement is convenient and accurate. The gas mass flow or standard volume flow can be obtained.

Wide range ratio, can measure gas with flow rate as high as 120Nm/s and as low as 0.1Nm/s. Can be used for gas leak detection.

Good seismic performance and long service life. The sensor has no moving parts and pressure sensing parts, and is not affected by vibration on measurement accuracy.

Easy to install and maintain. If site conditions permit, installation and maintenance can be achieved without stopping production. (Need special customization)

Digital design. Integral digital circuit measurement, accurate measurement and convenient maintenance.

Using RS-485 communication can realize factory automation and integration.

Oxygen, nitrogen, hydrogen, road gas and multi-component gas measurement.

Blast furnace gas and coke oven gas measurement.

Gas flow measurement for natural gas, liquefied gas, flare gas, etc.

Primary air and secondary air flow measurement of power plant blast furnace.

Flow measurement of underground ventilation or exhaust system in mines.

Flue gas measurement.

Compressed air measurement.

Extended reading: Gas mass flow controller working principle

  1. The vortex flowmeter has the following advantages:

The output signal is not affected by the temperature, pressure, and density components of the fluid, and is directly proportional to the fluid flow rate.

The sensing element does not contact the medium and has high reliability.

No moving parts, simple and firm structure.

Wide measuring range and high precision.

The pressure loss is small and the energy saving is significant.

Read more about: Vortex Shedding Flow Meter Working Principle

More Featured Air flow sensors

Extended reading: What is an air pressure transducer?

Sino-Inst’s air flow sensor offer reliable and accurate volume flow measurement in a large range of sizes and pressure rating while being fully compliant with international standards.

Sino-Inst is the risk-free choice for your gas flow measurement applications.

Sino-Inst supplies air flow sensors, like: gas turbine flow meter. vortex flowmeter, thermal mass flow meter, and more. More about Types Of Air Flow Measurement Instruments.

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