Magnetic coupling at elevated temperatures

Magnetic couplings are used in many functions within pump, chemical, pharmaceutical, course of and security industries. They are sometimes used with the aim of lowering put on, sealing of liquids from the setting, cleanliness needs or as a safety factor to brake over if torque suddenly 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 best torque density as potential. By optimizing the diameter, air gap, magnet measurement, number of poles and selection of magnet grade, it’s possible to design a magnetic coupling that fits any software within the vary from few millinewton meter as a lot as a quantity of hundred newton meters.
When solely optimizing for top torque, the designers typically are most likely to overlook contemplating the influence of temperature. If the designer refers to the Curie level of the individual magnets, he’ll claim that a Neodymium magnet would fulfill the requirements up to more than 300°C. Concurrently, you will need to embody the temperature dependencies on the remanence, which is seen as a reversible loss – sometimes round 0,11% per degree Celsius the temperature rises.
Furthermore, a neodymium magnet is beneath pressure during operation of the magnetic coupling. This means that irreversible demagnetization will occur long earlier than the Curie point has been reached, which usually limits using Neodymium-based magnetic coupling to temperatures below 150°C.
If greater temperatures are required, magnetic couplings made from Samarium Cobalt magnets (SmCo) are usually used. SmCo isn’t as robust as Neodymium magnets however can work up to 350°C. Furthermore, the temperature coefficient of SmCo is just 0,04% per diploma Celsius which implies that it can be used in applications the place performance 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 model new era of magnetic couplings has been developed by Sintex with assist from the Danish Innovation Foundation.
The function of the project was to develop a magnetic coupling that might broaden the working temperature space to achieve temperatures of molten salts around 600°C. By exchanging the inner drive with a magnetic materials containing a higher Curie level and boosting the magnetic field of the outer drive with special magnetic designs; it was possible to develop a magnetic coupling that started at a decrease torque stage at room temperature, however only had a minor discount in torque level as a operate of temperature. This resulted in superior efficiency above 160°C, irrespective of if the benchmark was towards a Neodymium- or Samarium Cobalt-based system. pressure gauge 4 นิ้ว ราคา can be seen in Figure 1, the place it’s 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 almost linear discount in torque.
The graph additionally shows 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 is still creating on the technology, however they must be challenged on torque degree at both totally different temperature, dimensions of the magnetic coupling or new applications that have not beforehand been potential with standard magnetic couplings, to have the ability to harvest the total potential of the High Hot know-how.
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 particular applications. Therefore, additional development will be made in shut collaboration with new companions.
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