Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many applications inside pump, chemical, pharmaceutical, process and safety industries. เครื่องมือที่ใช้ในการวัดความดัน are usually used with the purpose of lowering wear, sealing of liquids from the surroundings, cleanliness wants or as a security issue 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 in order to get the highest torque density as potential. By optimizing the diameter, air gap, magnet dimension, variety of poles and choice of magnet grade, it is potential to design a magnetic coupling that fits any application in the vary from few millinewton meter up to several hundred newton meters.
When solely optimizing for high torque, the designers often tend to overlook 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 as much as more than 300°C. Concurrently, it is necessary to 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 beneath strain during operation of the magnetic coupling. This signifies that irreversible demagnetization will happen long before the Curie level has been reached, which usually limits the utilization of 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 is not as strong as Neodymium magnets however can work as much as 350°C. Furthermore, the temperature coefficient of SmCo is only 0,04% per diploma Celsius which implies that it might be used in applications 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 new technology of magnetic couplings has been developed by Sintex with support from the Danish Innovation Foundation.
The function of the challenge was to develop a magnetic coupling that could broaden the working temperature area to succeed in temperatures of molten salts around 600°C. By exchanging the inside 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 started at a lower torque level at room temperature, however solely had a minor reduction in torque degree as a operate of temperature. This resulted in superior efficiency above 160°C, regardless of if the benchmark was in opposition to a Neodymium- or Samarium Cobalt-based system. This can be seen in Figure 1, where it’s shown that the torque level of the High Hot drives has been tested as a lot as 590°C on the inside drive and nonetheless carried out with an virtually linear reduction in torque.
The graph additionally shows 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 performance stability is important over a bigger temperature interval.
Conclusion At Sintex, the R&D department remains to be creating on the technology, but they must be challenged on torque level at either completely different temperature, dimensions of the magnetic coupling or new functions that have not previously been attainable with commonplace magnetic couplings, so as to harvest the full potential of the High Hot know-how.
The High Hot coupling is not seen as a standardized shelf product, however instead as custom-built by which is optimized for particular purposes. Therefore, further growth will be made in shut collaboration with new companions.
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