Magnetic coupling at elevated temperatures

Magnetic couplings are used in many purposes inside pump, chemical, pharmaceutical, course of and security industries. They are typically used with the aim of decreasing put on, sealing of liquids from the surroundings, cleanliness wants or as a security issue to brake over if torque abruptly rises.
The most common magnetic couplings are made with an outer and inside drive, each construct up with Neodymium magnets to have the ability to get the highest torque density as possible. By optimizing the diameter, air hole, magnet measurement, number of poles and choice of magnet grade, it is 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 solely optimizing for top torque, the designers usually tend to overlook considering the influence of temperature. If the designer refers to the Curie point of the person magnets, he’ll declare that a Neodymium magnet would fulfill the necessities up to greater than 300°C. Concurrently, it could be very important embrace the temperature dependencies on the remanence, which is seen as a reversible loss – sometimes around 0,11% per diploma Celsius the temperature rises.
Furthermore, a neodymium magnet is beneath stress during operation of the magnetic coupling. This implies that irreversible demagnetization will happen lengthy earlier than the Curie point has been reached, which typically limits using Neodymium-based magnetic coupling to temperatures beneath 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 but can work as much as 350°C. Furthermore, the temperature coefficient of SmCo is simply 0,04% per diploma Celsius which means that it may be used in purposes where performance 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 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 could broaden the working temperature space to succeed in temperatures of molten salts round 600°C. By exchanging the internal drive with a magnetic materials containing a better Curie level and boosting the magnetic area of the outer drive with special magnetic designs; it was attainable to develop a magnetic coupling that began at a lower torque stage at room temperature, however only had a minor discount in torque degree as a operate of temperature. This resulted in superior performance above 160°C, no matter if the benchmark was towards a Neodymium- or Samarium Cobalt-based system. เครื่องมือที่ใช้ในการวัดความดัน could be seen in Figure 1, where it’s proven that the torque level of the High Hot drives has been examined as a lot as 590°C on the inside drive and nonetheless performed with an nearly linear reduction in torque.
The graph additionally reveals that the temperature coefficient of the High Hot coupling is even lower than for the SmCo-system, which opens a lower temperature market where performance stability is essential over a larger temperature interval.
Conclusion At Sintex, the R&D department continues to be developing on the know-how, but they need to be challenged on torque stage at both different temperature, dimensions of the magnetic coupling or new applications that have not beforehand been possible with standard magnetic couplings, in order to harvest the complete potential of the High Hot expertise.
The High Hot coupling isn’t seen as a standardized shelf product, but as a substitute as custom-built by which is optimized for specific purposes. Therefore, additional improvement might be made in shut collaboration with new partners.
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