Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many purposes within pump, chemical, pharmaceutical, process and security industries. They are typically used with the aim of reducing wear, sealing of liquids from the environment, cleanliness wants or as a security factor to brake over if torque suddenly rises.
The commonest magnetic couplings are made with an outer and inner drive, each build up with Neodymium magnets to have the ability to get the highest torque density as possible. By optimizing the diameter, air gap, magnet dimension, variety of poles and selection of magnet grade, it is possible to design a magnetic coupling that fits any utility in the vary from few millinewton meter up to a number of hundred newton meters.
When solely optimizing for prime torque, the designers usually are likely to neglect contemplating the affect of temperature. If the designer refers to the Curie level of the individual magnets, he’ll claim that a Neodymium magnet would fulfill the requirements as a lot as greater 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 diploma Celsius the temperature rises.
Furthermore, a neodymium magnet is under pressure during operation of the magnetic coupling. This means that irreversible demagnetization will occur long before the Curie level has been reached, which usually limits the usage of Neodymium-based magnetic coupling to temperatures below 150°C.
If higher temperatures are required, magnetic couplings made of Samarium Cobalt magnets (SmCo) are usually used. SmCo is not as strong as Neodymium magnets however can work up to 350°C. Furthermore, the temperature coefficient of SmCo is only 0,04% per diploma Celsius which means that it can be utilized in applications where efficiency 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 new generation of magnetic couplings has been developed by Sintex with support from the Danish Innovation Foundation.
The objective of the challenge was to develop a magnetic coupling that could expand the working temperature area to succeed in temperatures of molten salts around 600°C. By exchanging the inner drive with a magnetic material containing the next Curie point and boosting the magnetic subject 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 solely had a minor discount in torque stage as a function of temperature. เครื่องมือวัดความดันคือ resulted in superior performance above 160°C, no matter if the benchmark was in opposition to a Neodymium- or Samarium Cobalt-based system. This may be seen in Figure 1, the place it’s shown that the torque degree of the High Hot drives has been tested up to 590°C on the inner drive and nonetheless performed with an virtually linear discount in torque.
The graph also shows that the temperature coefficient of the High Hot coupling is even decrease than for the SmCo-system, which opens a lower temperature market the place performance stability is necessary over a larger temperature interval.
Conclusion At Sintex, the R&D division continues to be creating on the know-how, however they need to be challenged on torque degree at either totally different temperature, dimensions of the magnetic coupling or new applications that have not beforehand been possible with normal magnetic couplings, in order to harvest the full potential of the High Hot expertise.
The High Hot coupling just isn’t seen as a standardized shelf product, but as a substitute as custom-built by which is optimized for specific purposes. Therefore, additional development shall be made in shut collaboration with new partners.
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