Magnetic coupling at elevated temperatures

Magnetic couplings are used in many applications within pump, chemical, pharmaceutical, course of and safety industries. They are usually used with the purpose of reducing put on, sealing of liquids from the setting, cleanliness wants or as a security issue to brake over if torque abruptly rises.
The most typical magnetic couplings are made with an outer and inside drive, each build up with Neodymium magnets in order to get the very best torque density as attainable. By optimizing the diameter, air gap, magnet dimension, variety of poles and choice of magnet grade, it is possible to design a magnetic coupling that fits any software within the vary from few millinewton meter up to several hundred newton meters.
When solely optimizing for Money , the designers usually are inclined to forget contemplating the influence of temperature. If the designer refers to the Curie level of the individual magnets, he will claim that a Neodymium magnet would fulfill the necessities as a lot as more than 300°C. Concurrently, it may be very important embrace the temperature dependencies on the remanence, which is seen as a reversible loss – usually around 0,11% per diploma Celsius the temperature rises.
Furthermore, Bonanza is beneath pressure throughout operation of the magnetic coupling. This signifies that irreversible demagnetization will occur lengthy before the Curie point has been reached, which usually limits the utilization of Neodymium-based magnetic coupling to temperatures beneath 150°C.
If higher temperatures are required, magnetic couplings manufactured from Samarium Cobalt magnets (SmCo) are typically used. SmCo isn’t as sturdy as Neodymium magnets however can work up to 350°C. Furthermore, the temperature coefficient of SmCo is simply 0,04% per diploma Celsius which implies that it could be used in functions where performance stability is required over a bigger temperature interval.
New era In collaboration with Copenhagen Atomics, Alfa Laval, Aalborg CSP and the Technical University of Denmark a new generation of magnetic couplings has been developed by Sintex with assist from the Danish Innovation Foundation.
The function of the challenge was to develop a magnetic coupling that might expand the working temperature space to reach temperatures of molten salts round 600°C. By exchanging the internal drive with a magnetic materials containing the next Curie point and boosting the magnetic area of the outer drive with special magnetic designs; it was potential to develop a magnetic coupling that started at a lower torque stage at room temperature, but only had a minor reduction in torque degree as a perform of temperature. This resulted in superior performance above 160°C, irrespective of if the benchmark was against a Neodymium- or Samarium Cobalt-based system. This may be seen in Figure 1, the place it is shown that the torque degree of the High Hot drives has been tested as much as 590°C on the inside drive and still carried out with an virtually linear discount in torque.
The graph also shows that the temperature coefficient of the High Hot coupling is even decrease than for the SmCo-system, which opens a lower temperature market where performance stability is important over a bigger temperature interval.
Conclusion At Sintex, the R&D department continues to be developing on the expertise, however they must be challenged on torque degree at both totally different temperature, dimensions of the magnetic coupling or new applications that have not beforehand been possible with standard magnetic couplings, in order to harvest the complete potential of the High Hot know-how.
The High Hot coupling just isn’t seen as a standardized shelf product, however instead as custom-built by which is optimized for particular applications. Therefore, further growth will be made in shut collaboration with new companions.

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