Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many applications inside pump, chemical, pharmaceutical, process and safety industries. They are usually used with the purpose of decreasing put on, sealing of liquids from the environment, cleanliness needs or as a safety factor to brake over if torque abruptly rises.
The most common magnetic couplings are made with an outer and inner drive, both build up with Neodymium magnets to be able to get the highest torque density as potential. By optimizing the diameter, air hole, magnet size, number of poles and selection of magnet grade, it’s potential to design a magnetic coupling that suits any utility in the vary from few millinewton meter as much as a number of hundred newton meters.
When solely optimizing for high torque, the designers often tend to forget contemplating the influence of temperature. If the designer refers again to the Curie point of the individual magnets, he’ll claim that a Neodymium magnet would fulfill the necessities 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 – usually round zero,11% per diploma Celsius the temperature rises.
Furthermore, a neodymium magnet is beneath stress during operation of the magnetic coupling. เกจวัดแรงดัน implies that irreversible demagnetization will happen long before the Curie level has been reached, which generally limits using Neodymium-based magnetic coupling to temperatures below 150°C.
If larger 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 up to 350°C. Furthermore, the temperature coefficient of SmCo is only 0,04% per degree Celsius which implies that it may be utilized in purposes where performance stability is required over a bigger temperature interval.
New generation In collaboration with Copenhagen Atomics, Alfa Laval, Aalborg CSP and the Technical University of Denmark a brand new generation of magnetic couplings has been developed by Sintex with support from the Danish Innovation Foundation.
The function of the project was to develop a magnetic coupling that might increase the working temperature space to succeed in temperatures of molten salts round 600°C. By exchanging the inner drive with a magnetic materials containing a higher Curie level and boosting the magnetic area of the outer drive with particular magnetic designs; it was possible to develop a magnetic coupling that started at a decrease torque stage at room temperature, but only had a minor discount in torque stage as a operate of temperature. This resulted in superior efficiency above 160°C, regardless of if the benchmark was towards a Neodymium- or Samarium Cobalt-based system. This can be seen in Figure 1, the place it’s proven that the torque stage of the High Hot drives has been examined up to 590°C on the inner drive and nonetheless carried out with an nearly linear reduction in torque.
The graph additionally shows 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 essential over a larger temperature interval.
Conclusion At Sintex, the R&D division continues to be growing on the expertise, however they need to be challenged on torque stage at either totally different temperature, dimensions of the magnetic coupling or new purposes that have not previously been attainable with normal magnetic couplings, so as to harvest the complete potential of the High Hot expertise.
The High Hot coupling isn’t seen as a standardized shelf product, but instead as custom-built by which is optimized for particular functions. Therefore, further growth will be made in shut collaboration with new companions.

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