Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many functions within pump, chemical, pharmaceutical, course of and safety industries. They are sometimes used with the purpose of lowering wear, sealing of liquids from the setting, cleanliness wants or as a safety factor to brake over if torque all of a sudden rises.
The commonest magnetic couplings are made with an outer and inside drive, each build up with Neodymium magnets so as to get the highest torque density as potential. By optimizing the diameter, air gap, magnet measurement, 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 up to a quantity of hundred newton meters.
When only optimizing for high torque, the designers often tend to overlook considering the affect of temperature. If the designer refers again to the Curie level of the person magnets, he’ll declare that a Neodymium magnet would fulfill the necessities as much as more than 300°C. Concurrently, it may be very important embody the temperature dependencies on the remanence, which is seen as a reversible loss – typically around 0,11% per degree Celsius the temperature rises.
Furthermore, a neodymium magnet is under stress during operation of the magnetic coupling. This means that irreversible demagnetization will happen lengthy earlier than the Curie point has been reached, which typically limits the use of Neodymium-based magnetic coupling to temperatures beneath 150°C.
If greater temperatures are required, magnetic couplings made of Samarium Cobalt magnets (SmCo) are sometimes used. SmCo is not as robust as Neodymium magnets but can work as much as 350°C. Furthermore, the temperature coefficient of SmCo is simply 0,04% per diploma Celsius which means that it can be used in purposes where efficiency stability is required over a larger temperature interval.
New technology In collaboration with Copenhagen Atomics, Alfa Laval, Aalborg CSP and the Technical University of Denmark a brand new era of magnetic couplings has been developed by Sintex with help from the Danish Innovation Foundation.
The purpose of the project was to develop a magnetic coupling that would broaden the working temperature area to achieve temperatures of molten salts round 600°C. By exchanging the internal drive with a magnetic materials containing the next Curie point and boosting the magnetic subject of the outer drive with particular magnetic designs; it was potential to develop a magnetic coupling that began at a decrease torque stage at room temperature, however only had a minor discount in torque level as a operate of temperature. This resulted in superior performance above 160°C, irrespective of if the benchmark was towards a Neodymium- or Samarium Cobalt-based system. pressure gauge ยี่ห้อ tk may be seen in Figure 1, the place it is shown that the torque stage of the High Hot drives has been examined up to 590°C on the inside drive and nonetheless carried out with an almost linear reduction in torque.
The graph additionally reveals 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 efficiency stability is necessary over a bigger temperature interval.
Conclusion At Sintex, the R&D division continues to be growing on the know-how, however they have to be challenged on torque level at both different temperature, dimensions of the magnetic coupling or new applications that haven’t beforehand been potential with normal magnetic couplings, in order to harvest the complete potential of the High Hot expertise.
The High Hot coupling isn’t seen as a standardized shelf product, but as a substitute as custom-built by which is optimized for specific applications. Therefore, further growth will be made in shut collaboration with new partners.

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