Magnetic coupling at elevated temperatures

Magnetic couplings are used in many purposes within pump, chemical, pharmaceutical, process and safety industries. They are usually used with the purpose of reducing put on, sealing of liquids from the surroundings, cleanliness wants or as a security factor to brake over if torque suddenly rises.
The most typical magnetic couplings are made with an outer and internal drive, both build up with Neodymium magnets to find a way to get the best torque density as possible. By optimizing the diameter, air hole, magnet dimension, variety of poles and selection of magnet grade, it is attainable to design a magnetic coupling that suits any software in the range from few millinewton meter up to several hundred newton meters.
When only optimizing for top torque, the designers often tend to neglect contemplating the influence of temperature. If the designer refers back to the Curie point of the individual magnets, he’ll claim that a Neodymium magnet would fulfill the necessities up to more than 300°C. Concurrently, you will want to include the temperature dependencies on the remanence, which is seen as a reversible loss – sometimes round zero,11% per diploma Celsius the temperature rises.
Furthermore, a neodymium magnet is underneath stress during operation of the magnetic coupling. This signifies that irreversible demagnetization will occur long before the Curie level has been reached, which usually limits the usage of Neodymium-based magnetic coupling to temperatures below 150°C.
If higher temperatures are required, magnetic couplings made of Samarium Cobalt magnets (SmCo) are sometimes used. SmCo just isn’t as sturdy as Neodymium magnets however can work up to 350°C. Furthermore, weksler ea14 of SmCo is just 0,04% per diploma Celsius which signifies that it may be used in functions where performance stability is needed over a bigger temperature interval.
New technology In collaboration with Copenhagen Atomics, Alfa Laval, Aalborg CSP and the Technical University of Denmark a new era of magnetic couplings has been developed by Sintex with assist from the Danish Innovation Foundation.
The purpose of the challenge was to develop a magnetic coupling that might increase the working temperature area to achieve temperatures of molten salts around 600°C. By exchanging the inside drive with a magnetic materials containing the next Curie level and boosting the magnetic field of the outer drive with special magnetic designs; it was potential to develop a magnetic coupling that began at a decrease torque level at room temperature, but solely had a minor reduction in torque degree as a perform of temperature. This resulted in superior efficiency 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 proven that the torque level of the High Hot drives has been examined as a lot as 590°C on the inside drive and still performed with an nearly linear reduction 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 the place efficiency stability is important over a bigger temperature interval.
Conclusion At Sintex, the R&D department is still growing on the expertise, but they must be challenged on torque stage at both totally different temperature, dimensions of the magnetic coupling or new applications that haven’t previously been possible with commonplace magnetic couplings, in order to harvest the complete potential of the High Hot expertise.
The High Hot coupling isn’t seen as a standardized shelf product, however as a substitute as custom-built by which is optimized for specific purposes. Therefore, further growth shall be made in close collaboration with new companions.

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