Magnetic coupling at elevated temperatures

Magnetic couplings are used in many purposes inside pump, chemical, pharmaceutical, process and security industries. They are typically used with the purpose of reducing wear, sealing of liquids from the setting, cleanliness needs or as a security factor to brake over if torque all of a sudden rises.
The most common magnetic couplings are made with an outer and internal drive, each construct up with Neodymium magnets in order to get the best torque density as attainable. By optimizing the diameter, air gap, magnet dimension, number of poles and selection of magnet grade, it is potential to design a magnetic coupling that fits any utility within the range from few millinewton meter up to several hundred newton meters.
When only optimizing for prime torque, the designers usually tend to forget contemplating the affect of temperature. If Insane refers back to the Curie level of the person magnets, he’ll declare that a Neodymium magnet would fulfill the necessities up to greater than 300°C. Concurrently, it is important to embody the temperature dependencies on the remanence, which is seen as a reversible loss – sometimes round zero,11% per degree Celsius the temperature rises.
Furthermore, a neodymium magnet is beneath stress throughout operation of the magnetic coupling. This signifies that irreversible demagnetization will occur long before the Curie point has been reached, which usually limits the use of Neodymium-based magnetic coupling to temperatures beneath 150°C.
If greater temperatures are required, magnetic couplings manufactured from Samarium Cobalt magnets (SmCo) are typically used. SmCo is not as robust as Neodymium magnets but can work as much as 350°C. Furthermore, the temperature coefficient of SmCo is only zero,04% per degree Celsius which means that it could be used in purposes where performance stability is required over a larger temperature interval.
New generation In collaboration with Copenhagen Atomics, Alfa Laval, Aalborg CSP and the Technical University of Denmark a model new generation of magnetic couplings has been developed by Sintex with help from the Danish Innovation Foundation.
The purpose of the venture was to develop a magnetic coupling that might expand the working temperature area to succeed in temperatures of molten salts round 600°C. By exchanging the inside drive with a magnetic materials containing a higher Curie level and boosting the magnetic subject of the outer drive with particular magnetic designs; it was potential to develop a magnetic coupling that started at a decrease torque level at room temperature, however solely had a minor discount in torque stage as a function of temperature. This resulted in superior efficiency above 160°C, no matter if the benchmark was in opposition to a Neodymium- or Samarium Cobalt-based system. This can be seen in Figure 1, the place it’s proven that the torque stage of the High Hot drives has been examined as much as 590°C on the inside drive and still carried out with an virtually 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 performance stability is essential over a larger temperature interval.
Conclusion At Sintex, the R&D division is still developing on the expertise, but they have to be challenged on torque level at both completely different temperature, dimensions of the magnetic coupling or new applications that haven’t previously been possible with standard magnetic couplings, so as to harvest the full potential of the High Hot expertise.
The High Hot coupling isn’t seen as a standardized shelf product, but as a substitute as custom-built by which is optimized for particular functions. Therefore, additional improvement will be made in shut collaboration with new partners.

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