Magnetic coupling at elevated temperatures

Magnetic couplings are used in many functions inside pump, chemical, pharmaceutical, process and security industries. They are typically used with the purpose of decreasing wear, sealing of liquids from the environment, cleanliness needs or as a safety factor to brake over if torque all of a sudden rises.
The most typical magnetic couplings are made with an outer and internal drive, each construct up with Neodymium magnets so as to get the very best torque density as possible. By optimizing the diameter, air gap, magnet measurement, number of poles and selection of magnet grade, it is attainable to design a magnetic coupling that suits any application within the range from few millinewton meter up to a quantity of hundred newton meters.
When solely optimizing for prime torque, the designers usually tend to neglect contemplating the influence 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 requirements up to greater than 300°C. Concurrently, you will want to embody the temperature dependencies on the remanence, which is seen as a reversible loss – usually around zero,11% per diploma Celsius the temperature rises.
Furthermore, a neodymium magnet is under stress throughout operation of the magnetic coupling. pressure gauge หน้าปัด 2 นิ้ว implies that irreversible demagnetization will happen lengthy earlier than the Curie point has been reached, which typically limits using Neodymium-based magnetic coupling to temperatures beneath 150°C.
If larger temperatures are required, magnetic couplings made of Samarium Cobalt magnets (SmCo) are typically used. SmCo isn’t as robust as Neodymium magnets but can work up to 350°C. Furthermore, the temperature coefficient of SmCo is simply zero,04% per diploma Celsius which implies that it might be utilized in purposes 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 brand new technology 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 area to achieve temperatures of molten salts around 600°C. By exchanging the internal drive with a magnetic materials containing a higher Curie level and boosting the magnetic field of the outer drive with particular magnetic designs; it was possible to develop a magnetic coupling that began at a decrease torque stage at room temperature, but only had a minor reduction in torque stage as a perform of temperature. This resulted in superior performance above 160°C, irrespective 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 proven that the torque degree of the High Hot drives has been tested as a lot as 590°C on the inner drive and nonetheless carried out with an almost linear discount in torque.
The graph also reveals that the temperature coefficient of the High Hot coupling is even lower than for the SmCo-system, which opens a decrease temperature market where efficiency stability is necessary over a bigger temperature interval.
Conclusion At Sintex, the R&D department continues to be developing on the know-how, but they need to be challenged on torque level at both totally different temperature, dimensions of the magnetic coupling or new purposes that have not previously been potential with normal magnetic couplings, so as to harvest the total potential of the High Hot expertise.
The High Hot coupling just isn’t seen as a standardized shelf product, however as an alternative as custom-built by which is optimized for specific purposes. Therefore, further development might be made in close collaboration with new partners.
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