Magnetic coupling at elevated temperatures

Magnetic couplings are used in many applications within pump, chemical, pharmaceutical, process and safety industries. They are sometimes used with the aim of reducing put on, sealing of liquids from the setting, cleanliness wants or as a safety issue to brake over if torque all of a sudden rises.
The commonest magnetic couplings are made with an outer and inside drive, each construct up with Neodymium magnets in order to get the highest torque density as attainable. By optimizing the diameter, air gap, magnet measurement, number of poles and choice of magnet grade, it is potential to design a magnetic coupling that fits any software in the range from few millinewton meter as much as several hundred newton meters.
When solely optimizing for prime torque, the designers often tend to neglect contemplating the affect of temperature. If the designer refers back to the Curie point of the individual magnets, he will claim that a Neodymium magnet would fulfill the requirements as much as greater than 300°C. Concurrently, it is necessary to embrace the temperature dependencies on the remanence, which is seen as a reversible loss – usually round 0,11% per degree Celsius the temperature rises.
Furthermore, pressure gauge วัด แรง ดัน น้ำ is under stress during operation of the magnetic coupling. This implies that irreversible demagnetization will occur lengthy before the Curie point has been reached, which generally limits the usage of Neodymium-based magnetic coupling to temperatures under 150°C.
If higher temperatures are required, magnetic couplings manufactured from Samarium Cobalt magnets (SmCo) are typically used. SmCo isn’t as strong as Neodymium magnets but can work as a lot as 350°C. Furthermore, the temperature coefficient of SmCo is just 0,04% per degree Celsius which implies that it could be used in functions the place performance stability is required over a bigger temperature interval.
New era In collaboration with Copenhagen Atomics, Alfa Laval, Aalborg CSP and the Technical University of Denmark a model new technology of magnetic couplings has been developed by Sintex with help from the Danish Innovation Foundation.
The function of the challenge was to develop a magnetic coupling that would increase the working temperature space to succeed in temperatures of molten salts round 600°C. By exchanging the internal 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 attainable to develop a magnetic coupling that started at a lower torque degree at room temperature, however only had a minor reduction in torque degree as a operate of temperature. This resulted in superior efficiency 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 level of the High Hot drives has been examined as much as 590°C on the inner drive and nonetheless performed with an almost linear reduction in torque.
The graph additionally exhibits that the temperature coefficient of the High Hot coupling is even decrease than for the SmCo-system, which opens a lower temperature market where efficiency stability is important over a bigger temperature interval.
Conclusion At Sintex, the R&D division remains to be developing on the know-how, however they need to be challenged on torque degree at either completely different temperature, dimensions of the magnetic coupling or new applications that haven’t previously been potential with normal magnetic couplings, so as to harvest the complete potential of the High Hot expertise.
The High Hot coupling is not seen as a standardized shelf product, but instead as custom-built by which is optimized for particular functions. Therefore, further improvement will be made in close collaboration with new companions.

Scroll to Top