Function material and selection of magnets in gas flow meters

Gas flow meters are important instruments in the field of industrial measurement, widely used in industries such as petroleum, chemical, metallurgy, and power. Magnets are used in many types of gas flow meters. Today, we will introduce the role, material, installation location, and selection considerations of magnets.

Firstly, let's talk about the function of magnets. Magnets in gas flow meters are not used for adsorption or fixation, but for signal transmission and isolation. For example, in types such as vortex flow meters and turbine flow meters, the fluid drives the internal impeller or rotor to rotate, and the permanent magnet installed on the rotor generates a periodically changing magnetic field. External sensors (such as Hall elements) detect this magnetic field change and convert it into an electrical signal. This design achieves complete isolation between the measurement chamber and the electronic part, ensuring sealing and improving the reliability of the instrument, especially suitable for situations such as gas and natural gas that require extremely high sealing requirements. In addition, some gas flow meters with certain structures may need to take on the role of driving and positioning.

In terms of magnet materials, the commonly used types of magnets for gas flow meters include sintered ferrite, injection molded ferrite, and bonded or injection molded neodymium iron boron.

Gas flow meter magnet ring

Where is the magnet installed?

On the impeller of the gas flowmeter, when the gas flow drives the impeller to rotate, the periodic changes in the magnetic field of the magnet are detected by the relevant Hall elements.

The selection needs to consider the long-term stability of the magnet, temperature resistance, moisture resistance, gas corrosion resistance, as well as the sensitivity and measurement accuracy of the sensor. Ferrite magnetic rings are suitable for mechanical or signal less demanding detection structures and have a significant application in the field of civil gas metering. The application of bonded neodymium iron boron magnetic rings is very common in intelligent gas meters and small-diameter gas flow meters.

The above is an introduction to the role, material, and selection of magnets in gas flow meters. If your company needs to purchase magnetic rings for flow meters, please contact us for samples and prices.

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