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Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many functions inside pump, chemical, pharmaceutical, course of and safety industries. They are typically used with the aim of reducing wear, sealing of liquids from the surroundings, 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 inner drive, each construct up with Neodymium magnets in order to get the best torque density as potential. By optimizing the diameter, air gap, magnet dimension, number of poles and choice of magnet grade, it’s potential to design a magnetic coupling that fits any application in the vary from few millinewton meter up to several hundred newton meters.
When only optimizing for high torque, the designers usually are most likely to forget considering the influence of temperature. If the designer refers back to the Curie level of the person magnets, he will claim that a Neodymium magnet would fulfill the requirements as much as greater than 300°C. Concurrently, it could be very important embody the temperature dependencies on the remanence, which is seen as a reversible loss – typically around zero,11% per degree Celsius the temperature rises.
Furthermore, a neodymium magnet is under strain during operation of the magnetic coupling. เพรสเชอร์เกจ means that irreversible demagnetization will happen long earlier than the Curie level has been reached, which usually limits using Neodymium-based magnetic coupling to temperatures under 150°C.
If larger temperatures are required, magnetic couplings made of Samarium Cobalt magnets (SmCo) are usually used. SmCo just isn’t as strong as Neodymium magnets but can work up to 350°C. Furthermore, the temperature coefficient of SmCo is only 0,04% per diploma Celsius which signifies that it can be used in applications where efficiency stability is required over a bigger temperature interval.
New era In collaboration with Copenhagen Atomics, Alfa Laval, Aalborg CSP and the Technical University of Denmark a brand new generation of magnetic couplings has been developed by Sintex with help from the Danish Innovation Foundation.
The function of the project was to develop a magnetic coupling that would increase the working temperature space to achieve temperatures of molten salts round 600°C. By exchanging the inside drive with a magnetic material containing the next Curie point and boosting the magnetic area of the outer drive with special magnetic designs; it was attainable to develop a magnetic coupling that started at a decrease torque degree at room temperature, but solely had a minor discount in torque stage as a operate of temperature. This resulted in superior performance above 160°C, regardless of if the benchmark was towards a Neodymium- or Samarium Cobalt-based system. This can be seen in Figure 1, the place it is shown that the torque stage of the High Hot drives has been tested up to 590°C on the inside drive and nonetheless performed with an nearly linear discount in torque.
The graph also exhibits 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 is still creating on the expertise, however they have to be challenged on torque stage at either totally different temperature, dimensions of the magnetic coupling or new functions that haven’t previously been attainable with commonplace magnetic couplings, so as to harvest the total potential of the High Hot know-how.
The High Hot coupling isn’t seen as a standardized shelf product, however as an alternative as custom-built by which is optimized for specific functions. Therefore, further development will be made in shut collaboration with new companions.