Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many functions within pump, chemical, pharmaceutical, course of and safety industries. They are usually used with the aim of decreasing wear, sealing of liquids from the surroundings, cleanliness wants or as a security issue to brake over if torque all of a sudden rises.
The most typical magnetic couplings are made with an outer and internal drive, each build up with Neodymium magnets to find a way to get the very best torque density as potential. By optimizing the diameter, air hole, magnet dimension, variety of poles and selection of magnet grade, it is potential to design a magnetic coupling that suits any utility within the range from few millinewton meter as a lot as several hundred newton meters.
When solely optimizing for top torque, the designers typically tend to overlook considering the influence of temperature. If the designer refers back to the Curie level of the person magnets, he will claim that a Neodymium magnet would fulfill the necessities as a lot as more than 300°C. Concurrently, you will want to include the temperature dependencies on the remanence, which is seen as a reversible loss – usually around 0,11% per degree Celsius the temperature rises.
Furthermore, a neodymium magnet is under stress throughout operation of the magnetic coupling. เกจวัดแรงดัน250bar means that irreversible demagnetization will occur lengthy before the Curie point has been reached, which typically limits the use of Neodymium-based magnetic coupling to temperatures under 150°C.
If greater temperatures are required, magnetic couplings made of Samarium Cobalt magnets (SmCo) are usually used. SmCo is not as robust as Neodymium magnets but can work as a lot as 350°C. Furthermore, the temperature coefficient of SmCo is only 0,04% per degree Celsius which means that it can be utilized in applications where efficiency stability is needed over a bigger temperature interval.
New technology 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 help from the Danish Innovation Foundation.
The purpose of the project was to develop a magnetic coupling that could broaden the working temperature space to reach temperatures of molten salts round 600°C. By exchanging the inner drive with a magnetic material containing the next Curie level and boosting the magnetic area of the outer drive with special magnetic designs; it was potential to develop a magnetic coupling that began at a lower torque degree at room temperature, however solely had a minor reduction in torque degree as a operate 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. This could be seen in Figure 1, the place it’s proven that the torque degree of the High Hot drives has been examined up to 590°C on the internal drive and nonetheless carried out with an almost 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 division is still developing on the technology, however they must be challenged on torque degree at either completely different temperature, dimensions of the magnetic coupling or new functions that haven’t beforehand been potential with normal magnetic couplings, in order to harvest the full potential of the High Hot know-how.
The High Hot coupling isn’t seen as a standardized shelf product, but instead as custom-built by which is optimized for particular purposes. Therefore, further development might be made in shut collaboration with new companions.
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