Magnetic couplings are used in many purposes inside pump, chemical, pharmaceutical, course of and safety industries. They are usually used with the purpose of lowering wear, sealing of liquids from the environment, cleanliness wants or as a security factor to brake over if torque all of a sudden rises.
The most common magnetic couplings are made with an outer and inner drive, each construct up with Neodymium magnets to be able to get the best torque density as possible. By optimizing the diameter, air gap, magnet measurement, number of poles and selection of magnet grade, it is possible to design a magnetic coupling that fits any application within the vary from few millinewton meter as much as a number of hundred newton meters.
When only optimizing for prime torque, the designers often are inclined to overlook considering the affect of temperature. If the designer refers to the Curie point of the person magnets, he will claim that a Neodymium magnet would fulfill the requirements up to 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 round 0,11% per degree Celsius the temperature rises.
Furthermore, a neodymium magnet is beneath pressure during operation of the magnetic coupling. This implies that irreversible demagnetization will occur long earlier than the Curie point has been reached, which usually limits the utilization of Neodymium-based magnetic coupling to temperatures beneath 150°C.
If Key are required, magnetic couplings manufactured from Samarium Cobalt magnets (SmCo) are typically used. SmCo just isn’t as sturdy as Neodymium magnets but can work up to 350°C. Furthermore, the temperature coefficient of SmCo is just 0,04% per degree Celsius which means that it could be utilized in applications where performance stability is required over a bigger temperature interval.
New generation 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 help from the Danish Innovation Foundation.
The objective of the challenge was to develop a magnetic coupling that might broaden the working temperature area to reach temperatures of molten salts around 600°C. By exchanging the inner drive with a magnetic material containing a higher Curie point and boosting the magnetic area of the outer drive with particular magnetic designs; it was attainable to develop a magnetic coupling that started at a decrease torque stage at room temperature, but solely had a minor reduction in torque level as a perform of temperature. This resulted in superior performance above 160°C, no matter if the benchmark was in opposition to a Neodymium- or Samarium Cobalt-based system. This can be seen in Figure 1, the place it’s shown that the torque level of the High Hot drives has been tested as a lot as 590°C on the inner drive and still performed with an virtually linear discount 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 where efficiency stability is important over a larger temperature interval.
Conclusion At Sintex, the R&D department remains to be creating on the expertise, however they have to be challenged on torque stage at either completely different temperature, dimensions of the magnetic coupling or new applications that haven’t previously been possible with standard magnetic couplings, so as to harvest the total potential of the High Hot expertise.
The High Hot coupling isn’t seen as a standardized shelf product, however instead as custom-built by which is optimized for specific purposes. Therefore, further development shall be made in close collaboration with new partners.
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