Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many purposes within pump, chemical, pharmaceutical, process and security industries. They are sometimes used with the aim of lowering put on, sealing of liquids from the surroundings, cleanliness wants or as a safety factor to brake over if torque all of a sudden rises.
The most common magnetic couplings are made with an outer and internal drive, each build up with Neodymium magnets in order to get the highest torque density as possible. By optimizing the diameter, air hole, magnet dimension, number of poles and choice of magnet grade, it is possible to design a magnetic coupling that suits any software within the range from few millinewton meter up to a quantity of hundred newton meters.
When only optimizing for high torque, the designers usually are most likely to overlook considering the affect of temperature. If the designer refers back 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 could be very important include the temperature dependencies on the remanence, which is seen as a reversible loss – sometimes around 0,11% per degree Celsius the temperature rises.
Furthermore, a neodymium magnet is underneath pressure throughout operation of the magnetic coupling. This means that irreversible demagnetization will occur lengthy before the Curie point has been reached, which generally limits the utilization of Neodymium-based magnetic coupling to temperatures below 150°C.
If greater temperatures are required, magnetic couplings manufactured from Samarium Cobalt magnets (SmCo) are typically used. SmCo isn’t as sturdy as Neodymium magnets however can work as a lot as 350°C. Furthermore, the temperature coefficient of SmCo is simply 0,04% per diploma Celsius which means that it can be used in functions the place efficiency stability is needed over a bigger temperature interval.
pressure gauge ออก หลัง In collaboration with Copenhagen Atomics, Alfa Laval, Aalborg CSP and the Technical University of Denmark a new technology 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 could broaden the working temperature space to achieve temperatures of molten salts around 600°C. By exchanging the internal drive with a magnetic material 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 degree at room temperature, but solely had a minor discount in torque degree as a perform of temperature. This resulted in superior efficiency above 160°C, no matter if the benchmark was against a Neodymium- or Samarium Cobalt-based system. This may be seen in Figure 1, the place it is shown that the torque level of the High Hot drives has been tested as a lot as 590°C on the internal drive and nonetheless carried out with an almost linear reduction in torque.
pressure gauge หลักการ ทํา งาน 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 necessary over a larger temperature interval.
Conclusion At Sintex, the R&D department continues to be creating 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 potential with commonplace magnetic couplings, to have the ability to harvest the total potential of the High Hot expertise.
The High Hot coupling just isn’t seen as a standardized shelf product, but as a substitute as custom-built by which is optimized for particular purposes. Therefore, further improvement will be made in close collaboration with new partners.
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