Magnetic couplings are utilized in many purposes inside pump, chemical, pharmaceutical, process and security industries. They are sometimes used with the aim of decreasing put on, sealing of liquids from the setting, cleanliness wants or as a security issue to brake over if torque all of a sudden rises.
The commonest magnetic couplings are made with an outer and internal drive, each build up with Neodymium magnets in order to get the very best torque density as possible. By optimizing the diameter, air hole, magnet dimension, number of poles and selection of magnet grade, it’s potential to design a magnetic coupling that fits any software within the range from few millinewton meter up to several hundred newton meters.
When solely optimizing for high torque, the designers typically are inclined to neglect contemplating the affect of temperature. If the designer refers again to the Curie point of the individual magnets, he will claim that a Neodymium magnet would fulfill the necessities up to greater than 300°C. Concurrently, it is important to include the temperature dependencies on the remanence, which is seen as a reversible loss – usually round 0,11% per diploma Celsius the temperature rises.
Furthermore, pressure gauge ยี่ห้อ tk is under pressure during operation of the magnetic coupling. This means that irreversible demagnetization will happen lengthy before the Curie level has been reached, which typically limits the usage of Neodymium-based magnetic coupling to temperatures under 150°C.
If larger temperatures are required, magnetic couplings made of Samarium Cobalt magnets (SmCo) are typically used. SmCo is not as robust as Neodymium magnets however can work up to 350°C. Furthermore, the temperature coefficient of SmCo is only 0,04% per degree Celsius which signifies that it may be used in purposes where efficiency stability is needed over a larger 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 function 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 inside drive with a magnetic materials containing the next Curie level and boosting the magnetic subject of the outer drive with special magnetic designs; it was possible to develop a magnetic coupling that started at a lower torque stage at room temperature, however solely had a minor discount in torque stage 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, where it’s shown that the torque level of the High Hot drives has been tested up to 590°C on the inner drive and still performed with an virtually linear reduction 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 the place performance stability is essential 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 completely different temperature, dimensions of the magnetic coupling or new applications that haven’t previously been potential with standard magnetic couplings, in order to harvest the complete potential of the High Hot know-how.
The High Hot coupling just isn’t seen as a standardized shelf product, however instead as custom-built by which is optimized for particular purposes. Therefore, further development will be made in close collaboration with new companions.
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