Magnetic coupling at elevated temperatures

Magnetic couplings are used in many applications inside pump, chemical, pharmaceutical, course of and safety industries. They are typically used with the aim of reducing 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 inside drive, each construct up with Neodymium magnets so as 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 is attainable to design a magnetic coupling that suits any software in the vary from few millinewton meter up to a quantity of hundred newton meters.
When only optimizing for high torque, the designers often are probably to overlook considering the influence of temperature. If the designer refers again to the Curie level of the person magnets, he will declare that a Neodymium magnet would fulfill the necessities as much as more than 300°C. Concurrently, it may be very important embody the temperature dependencies on the remanence, which is seen as a reversible loss – usually around zero,11% per degree Celsius the temperature rises.
Furthermore, a neodymium magnet is beneath stress throughout operation of the magnetic coupling. Last chance signifies that irreversible demagnetization will happen lengthy before the Curie level has been reached, which usually limits the usage of Neodymium-based magnetic coupling to temperatures below 150°C.
If greater temperatures are required, magnetic couplings made of Samarium Cobalt magnets (SmCo) are sometimes used. SmCo is not as strong as Neodymium magnets but can work as much as 350°C. Furthermore, the temperature coefficient of SmCo is simply zero,04% per diploma Celsius which implies that it can be used in functions the place performance stability is needed over a larger temperature interval.
New era 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 objective of the venture was to develop a magnetic coupling that might broaden the working temperature area to achieve temperatures of molten salts around 600°C. By exchanging the inside drive with a magnetic material containing a higher Curie point and boosting the magnetic subject of the outer drive with special magnetic designs; it was potential to develop a magnetic coupling that started at a decrease torque stage at room temperature, but solely had a minor reduction in torque level as a function of temperature. This resulted in superior performance above 160°C, irrespective of if the benchmark was against a Neodymium- or Samarium Cobalt-based system. This can be seen in Figure 1, where it is shown that the torque level of the High Hot drives has been tested as a lot as 590°C on the inner 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 lower than for the SmCo-system, which opens a lower temperature market the place efficiency stability is necessary over a larger temperature interval.
Conclusion At Sintex, the R&D division remains to be creating on the know-how, however they need to be challenged on torque stage at either totally different temperature, dimensions of the magnetic coupling or new functions that haven’t beforehand been attainable with commonplace magnetic couplings, so as to harvest the full potential of the High Hot technology.
The High Hot coupling is not seen as a standardized shelf product, but instead as custom-built by which is optimized for specific applications. Therefore, further improvement might be made in shut collaboration with new companions.
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