Magnetic coupling at elevated temperatures

Magnetic couplings are used in many applications within pump, chemical, pharmaceutical, course of and security industries. They are typically used with the purpose of lowering put on, sealing of liquids from the setting, cleanliness needs or as a security issue to brake over if torque abruptly rises.
The most common magnetic couplings are made with an outer and inner drive, both build up with Neodymium magnets to be able to get the best torque density as possible. By optimizing the diameter, air gap, magnet dimension, variety of poles and selection of magnet grade, it’s attainable to design a magnetic coupling that fits any application within the range from few millinewton meter as a lot as a number of hundred newton meters.
When only optimizing for high torque, the designers often tend to neglect contemplating the affect of temperature. If the designer refers to the Curie point of the person magnets, he will claim that a Neodymium magnet would fulfill the requirements up to greater than 300°C. Concurrently, you will need to embody the temperature dependencies on the remanence, which is seen as a reversible loss – sometimes around zero,11% per diploma Celsius the temperature rises.
Furthermore, a neodymium magnet is underneath pressure during operation of the magnetic coupling. This means that irreversible demagnetization will occur lengthy earlier than the Curie level has been reached, which typically limits the usage of Neodymium-based magnetic coupling to temperatures under 150°C.
If greater temperatures are required, magnetic couplings made from Samarium Cobalt magnets (SmCo) are usually used. SmCo just isn’t as sturdy as Neodymium magnets however can work up to 350°C. Furthermore, the temperature coefficient of SmCo is simply zero,04% per diploma Celsius which means that it can be utilized in functions the place performance stability is needed over a bigger 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 assist from the Danish Innovation Foundation.
The function of the project was to develop a magnetic coupling that would expand the working temperature area to succeed in temperatures of molten salts around 600°C. By exchanging the inside drive with a magnetic material containing the next Curie point and boosting the magnetic field of the outer drive with special magnetic designs; it was potential to develop a magnetic coupling that started at a lower torque level 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, no matter if the benchmark was in opposition to a Neodymium- or Samarium Cobalt-based system. เกจวัดความดันน้ำ could be seen in Figure 1, the place it is proven that the torque degree of the High Hot drives has been tested up to 590°C on the internal drive and still carried out with an almost linear discount in torque.
The graph also exhibits that the temperature coefficient of the High Hot coupling is even lower than for the SmCo-system, which opens a lower temperature market where efficiency stability is necessary over a larger temperature interval.
Conclusion At Sintex, the R&D division continues to be creating on the know-how, however they have to be challenged on torque stage at both completely different temperature, dimensions of the magnetic coupling or new functions that have not previously been potential with standard magnetic couplings, in order to harvest the total potential of the High Hot technology.
The High Hot coupling just isn’t seen as a standardized shelf product, but as an alternative as custom-built by which is optimized for specific functions. Therefore, further growth will be made in close collaboration with new partners.
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