Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many applications inside pump, chemical, pharmaceutical, course of and safety industries. They are sometimes used with the aim of lowering put on, sealing of liquids from the environment, cleanliness wants or as a safety issue to brake over if torque abruptly rises.
The most typical magnetic couplings are made with an outer and internal drive, each construct up with Neodymium magnets in order to get the highest torque density as potential. By optimizing the diameter, air hole, magnet measurement, variety of poles and selection of magnet grade, it’s potential to design a magnetic coupling that suits any utility within the range from few millinewton meter up to several hundred newton meters.
When only optimizing for top torque, the designers usually tend to neglect considering the influence of temperature. If the designer refers to the Curie point of the individual magnets, he’ll declare that a Neodymium magnet would fulfill the necessities as much as greater than 300°C. Concurrently, it may be very important embrace the temperature dependencies on the remanence, which is seen as a reversible loss – typically round zero,11% per diploma Celsius the temperature rises.
Furthermore, a neodymium magnet is underneath stress throughout operation of the magnetic coupling. This means that irreversible demagnetization will occur long before the Curie point has been reached, which usually limits the utilization of Neodymium-based magnetic coupling to temperatures beneath 150°C.
If greater temperatures are required, magnetic couplings made of Samarium Cobalt magnets (SmCo) are sometimes used. SmCo just isn’t as strong as Neodymium magnets but can work as much as 350°C. Furthermore, the temperature coefficient of SmCo is only 0,04% per degree Celsius which signifies that it could be utilized in purposes the place efficiency stability is needed over a larger temperature interval.
New technology In collaboration with Copenhagen Atomics, Alfa Laval, Aalborg CSP and the Technical University of Denmark a brand new era 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 could broaden the working temperature space to succeed in temperatures of molten salts round 600°C. By exchanging the inner drive with a magnetic material containing a better Curie point and boosting the magnetic area of the outer drive with particular 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 discount in torque degree as a function of temperature. This resulted in superior performance above 160°C, regardless of if the benchmark was in opposition to a Neodymium- or Samarium Cobalt-based system. This may be seen in Figure 1, the place it is proven that the torque stage of the High Hot drives has been examined up to 590°C on the internal drive and still carried out with an nearly linear discount in torque.
เกจวัดแรงดันแบบแห้ง exhibits 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 necessary over a bigger temperature interval.
Conclusion At Sintex, the R&D division continues to be creating on the know-how, however they need to be challenged on torque level at either totally different temperature, dimensions of the magnetic coupling or new purposes that haven’t previously been potential with normal magnetic couplings, to have the ability to harvest the full potential of the High Hot know-how.
The High Hot coupling is not seen as a standardized shelf product, but as an alternative as custom-built by which is optimized for particular applications. Therefore, further improvement might be made in shut collaboration with new companions.