Magnetic coupling at elevated temperatures

Magnetic couplings are used in many purposes inside pump, chemical, pharmaceutical, process and safety industries. They are usually used with the aim of decreasing put on, sealing of liquids from the environment, cleanliness wants or as a security factor to brake over if torque abruptly rises.
The most typical magnetic couplings are made with an outer and inner drive, both build up with Neodymium magnets to find a way to get the best torque density as potential. By optimizing the diameter, air hole, magnet measurement, variety of poles and choice of magnet grade, it’s potential to design a magnetic coupling that suits any software in the vary from few millinewton meter as much as several hundred newton meters.
When only optimizing for Private , the designers usually tend to forget considering the influence of temperature. If the designer refers back to the Curie point of the person magnets, he will declare that a Neodymium magnet would fulfill the requirements up to more than 300°C. Concurrently, you will need to embody the temperature dependencies on the remanence, which is seen as a reversible loss – typically around 0,11% per diploma Celsius the temperature rises.
Furthermore, a neodymium magnet is underneath strain throughout operation of the magnetic coupling. This implies that irreversible demagnetization will occur long before the Curie level has been reached, which generally limits using Neodymium-based magnetic coupling to temperatures under 150°C.
If higher temperatures are required, magnetic couplings manufactured from Samarium Cobalt magnets (SmCo) are sometimes used. SmCo isn’t as robust as Neodymium magnets however can work up to 350°C. Furthermore, the temperature coefficient of SmCo is only 0,04% per diploma Celsius which signifies that it might be used in purposes the place 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 new generation of magnetic couplings has been developed by Sintex with assist from the Danish Innovation Foundation.
The objective of the venture was to develop a magnetic coupling that would broaden the working temperature space to reach temperatures of molten salts round 600°C. By exchanging the inside drive with a magnetic material containing a higher Curie point and boosting the magnetic field of the outer drive with particular magnetic designs; it was potential to develop a magnetic coupling that began at a decrease torque level at room temperature, but only had a minor discount in torque level 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 can be seen in Figure 1, the place it is proven that the torque stage of the High Hot drives has been tested as much as 590°C on the inside drive and still performed with an almost linear reduction in torque.
The graph additionally exhibits that the temperature coefficient of the High Hot coupling is even decrease than for the SmCo-system, which opens a decrease temperature market the place efficiency stability is necessary over a larger temperature interval.
Conclusion At Sintex, the R&D division is still creating on the expertise, but they must be challenged on torque stage at either different temperature, dimensions of the magnetic coupling or new applications that haven’t beforehand been attainable with standard magnetic couplings, to have the ability to harvest the full potential of the High Hot expertise.
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 applications. Therefore, further growth might be made in close collaboration with new companions.

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