Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many purposes within pump, chemical, pharmaceutical, course of and safety industries. They are usually used with the aim of lowering wear, sealing of liquids from the setting, cleanliness needs or as a safety issue to brake over if torque suddenly rises.
The commonest magnetic couplings are made with an outer and internal drive, each build up with Neodymium magnets to be able to get the highest torque density as possible. By optimizing the diameter, air hole, magnet size, variety of poles and choice of magnet grade, it’s possible to design a magnetic coupling that suits any software within the range from few millinewton meter as much as a number of hundred newton meters.
When solely optimizing for top torque, the designers usually are most likely to overlook considering the influence 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, you will want to include 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 underneath strain throughout operation of the magnetic coupling. This implies that irreversible demagnetization will happen lengthy earlier than the Curie point has been reached, which usually limits the use of Neodymium-based magnetic coupling to temperatures beneath 150°C.
If larger temperatures are required, magnetic couplings made of Samarium Cobalt magnets (SmCo) are usually used. SmCo isn’t as strong as Neodymium magnets but can work up to 350°C. Furthermore, the temperature coefficient of SmCo is simply 0,04% per degree Celsius which signifies that it can be utilized in purposes the place 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 new era of magnetic couplings has been developed by Sintex with assist from the Danish Innovation Foundation.
The objective of the project was to develop a magnetic coupling that could broaden the working temperature area to succeed in temperatures of molten salts around 600°C. By exchanging the inside drive with a magnetic material containing a higher Curie level and boosting the magnetic subject of the outer drive with special magnetic designs; it was potential to develop a magnetic coupling that began at a lower torque level at room temperature, however solely had a minor discount in torque degree as a perform of temperature. This resulted in superior performance above 160°C, no matter if the benchmark was towards a Neodymium- or Samarium Cobalt-based system. This could be seen in Figure 1, where it’s proven that the torque stage of the High Hot drives has been examined as a lot as 590°C on the internal drive and still performed with an almost linear reduction in torque.
The graph also shows that the temperature coefficient of the High Hot coupling is even lower than for the SmCo-system, which opens a lower temperature market the place performance stability is essential over a bigger temperature interval.
Conclusion At Sintex, the R&D division continues to be growing on the know-how, but they must be challenged on torque stage at both different temperature, dimensions of the magnetic coupling or new purposes that haven’t previously been attainable with commonplace magnetic couplings, to have the ability to harvest the complete potential of the High Hot technology.
The High Hot coupling is not seen as a standardized shelf product, but as a substitute as custom-built by which is optimized for specific functions. Therefore, เกจวัดแรงดันแบบแห้ง will be made in shut collaboration with new partners.
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