Magnetic coupling at elevated temperatures

Magnetic couplings are used in many applications within pump, chemical, pharmaceutical, process and safety industries. They are typically used with the purpose of reducing wear, 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, each build up with Neodymium magnets so as to get the highest torque density as potential. By optimizing the diameter, air hole, magnet size, number of poles and choice of magnet grade, it’s potential to design a magnetic coupling that suits any utility within the range from few millinewton meter as much as several hundred newton meters.
When solely optimizing for top torque, the designers typically are most likely to forget contemplating the influence of temperature. If the designer refers to the Curie point of the individual magnets, he will declare that a Neodymium magnet would fulfill the requirements as a lot as greater than 300°C. Concurrently, it is very important embrace the temperature dependencies on the remanence, which is seen as a reversible loss – usually around zero,11% per degree Celsius the temperature rises.
Furthermore, a neodymium magnet is underneath strain during operation of the magnetic coupling. This signifies that irreversible demagnetization will occur lengthy earlier than the Curie point has been reached, which usually limits the usage of Neodymium-based magnetic coupling to temperatures below 150°C.
If greater temperatures are required, magnetic couplings made from Samarium Cobalt magnets (SmCo) are sometimes used. SmCo is not as sturdy as Neodymium magnets but can work up to 350°C. Furthermore, the temperature coefficient of SmCo is just zero,04% per diploma Celsius which means that it might be utilized in purposes the place efficiency stability is needed over a larger temperature interval.
New technology In collaboration with Copenhagen Atomics, Alfa Laval, Aalborg CSP and the Technical University of Denmark a new technology of magnetic couplings has been developed by Sintex with assist from the Danish Innovation Foundation.
The purpose of the venture was to develop a magnetic coupling that would expand the working temperature area to reach temperatures of molten salts around 600°C. By exchanging the internal drive with a magnetic material containing a better Curie level and boosting the magnetic field of the outer drive with special magnetic designs; it was possible to develop a magnetic coupling that began at a lower torque degree at room temperature, however only had a minor discount in torque level as a function of temperature. This resulted in superior performance above 160°C, regardless of if the benchmark was in opposition to a Neodymium- or Samarium Cobalt-based system. This could be seen in Figure 1, the place it is shown that the torque level of the High Hot drives has been examined up to 590°C on the inside drive and nonetheless performed with an virtually linear discount in torque.
ขนาดpressuregauge shows 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 necessary over a larger temperature interval.
Conclusion At Sintex, the R&D division continues to be developing on the know-how, however they have to be challenged on torque stage at both totally different temperature, dimensions of the magnetic coupling or new functions that have not previously been potential with normal magnetic couplings, in order to harvest the full potential of the High Hot expertise.
The High Hot coupling is not seen as a standardized shelf product, however as a substitute as custom-built by which is optimized for specific functions. Therefore, additional growth will be made in shut collaboration with new partners.

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