Magnetic coupling at elevated temperatures

Frugal are utilized in many functions within pump, chemical, pharmaceutical, process and security industries. They are typically used with the aim of lowering wear, sealing of liquids from the surroundings, cleanliness needs or as a security factor to brake over if torque all of a sudden rises.
The most typical magnetic couplings are made with an outer and inside drive, both construct up with Neodymium magnets so as to get the very best torque density as potential. 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 suits any utility in the range from few millinewton meter up to a number of hundred newton meters.
When only optimizing for prime torque, the designers usually are most likely to forget considering the affect of temperature. If the designer refers 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 embrace 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 under pressure during operation of the magnetic coupling. This signifies that irreversible demagnetization will occur long before the Curie level has been reached, which generally limits the use of Neodymium-based magnetic coupling to temperatures beneath 150°C.
If greater temperatures are required, magnetic couplings made from Samarium Cobalt magnets (SmCo) are sometimes used. SmCo just isn’t as sturdy as Neodymium magnets however can work as much as 350°C. Furthermore, the temperature coefficient of SmCo is only zero,04% per diploma Celsius which means that it could be used in purposes the place efficiency stability is required over a bigger temperature interval.
New technology In collaboration with Copenhagen Atomics, Alfa Laval, Aalborg CSP and the Technical University of Denmark a brand new generation of magnetic couplings has been developed by Sintex with assist from the Danish Innovation Foundation.
The function of the venture was to develop a magnetic coupling that would expand the working temperature space to achieve temperatures of molten salts around 600°C. By exchanging the inner drive with a magnetic materials containing a better Curie level and boosting the magnetic area of the outer drive with particular magnetic designs; it was attainable to develop a magnetic coupling that began at a lower 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, irrespective of if the benchmark was against a Neodymium- or Samarium Cobalt-based system. This could be seen in Figure 1, where it’s shown that the torque stage of the High Hot drives has been examined up to 590°C on the inside drive and nonetheless performed with an virtually linear discount in torque.
The graph also exhibits 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 larger temperature interval.
Conclusion At Sintex, the R&D division remains to be creating on the know-how, but they need to be challenged on torque level at both completely different temperature, dimensions of the magnetic coupling or new functions that haven’t beforehand been attainable with commonplace magnetic couplings, to find a way to harvest the total potential of the High Hot technology.
The High Hot coupling is not seen as a standardized shelf product, but as an alternative as custom-built by which is optimized for specific functions. Therefore, additional improvement will be made in shut collaboration with new partners.
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