Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many functions within pump, chemical, pharmaceutical, course of and security industries. They are usually used with the purpose of decreasing put on, sealing of liquids from the setting, cleanliness needs or as a security factor to brake over if torque suddenly rises.
The commonest magnetic couplings are made with an outer and inside drive, each build up with Neodymium magnets in order to get the very best torque density as possible. By optimizing the diameter, air gap, magnet size, number of poles and choice of magnet grade, it’s attainable to design a magnetic coupling that fits any utility in the vary from few millinewton meter up to several hundred newton meters.
When only optimizing for high torque, the designers typically tend to forget considering the influence of temperature. If the designer refers to the Curie point of the individual magnets, he’ll declare that a Neodymium magnet would fulfill the requirements up to more than 300°C. Concurrently, it is essential to embody 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. เกจ์อาร์กอนsumo implies that irreversible demagnetization will occur long before the Curie point has been reached, which generally limits the use of Neodymium-based magnetic coupling to temperatures beneath 150°C.
If higher temperatures are required, magnetic couplings manufactured from Samarium Cobalt magnets (SmCo) are usually used. SmCo is not as robust as Neodymium magnets however can work up to 350°C. Furthermore, the temperature coefficient of SmCo is simply 0,04% per degree Celsius which means that it can be used in applications the place 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 new era of magnetic couplings has been developed by Sintex with help from the Danish Innovation Foundation.
The objective of the challenge was to develop a magnetic coupling that might expand the working temperature space to succeed in temperatures of molten salts round 600°C. By exchanging the inner drive with a magnetic material containing a higher Curie level and boosting the magnetic field of the outer drive with particular magnetic designs; it was potential to develop a magnetic coupling that started at a lower torque stage at room temperature, but solely had a minor reduction in torque degree as a perform of temperature. This resulted in superior performance above 160°C, no matter if the benchmark was against a Neodymium- or Samarium Cobalt-based system. This may be seen in Figure 1, where it’s shown that the torque degree of the High Hot drives has been tested up to 590°C on the internal drive and nonetheless carried out with an nearly linear reduction in torque.
The graph also shows that the temperature coefficient of the High Hot coupling is even lower than for the SmCo-system, which opens a decrease temperature market where performance stability is necessary over a larger temperature interval.
Conclusion At Sintex, the R&D department remains to be creating on the expertise, but they have to be challenged on torque stage at either different temperature, dimensions of the magnetic coupling or new applications that haven’t previously been attainable with commonplace magnetic couplings, to have the ability to harvest the total potential of the High Hot expertise.
The High Hot coupling isn’t seen as a standardized shelf product, however as an alternative as custom-built by which is optimized for particular functions. Therefore, further growth might be made in close collaboration with new companions.