Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many applications inside pump, chemical, pharmaceutical, course of and security industries. They are usually used with the purpose of reducing put on, sealing of liquids from the environment, cleanliness needs or as a security issue to brake over if torque suddenly rises.
The most typical magnetic couplings are made with an outer and inside drive, both construct up with Neodymium magnets to find a way to get the highest torque density as attainable. By optimizing the diameter, air hole, magnet size, number of poles and selection of magnet grade, it’s attainable to design a magnetic coupling that fits any application within the vary from few millinewton meter as much as a quantity of hundred newton meters.
When only optimizing for prime torque, the designers usually tend to overlook contemplating the influence of temperature. If the designer refers to the Curie point of the individual magnets, he will claim that a Neodymium magnet would fulfill the necessities up to more than 300°C. Concurrently, it may be very important embody the temperature dependencies on the remanence, which is seen as a reversible loss – typically around 0,11% per diploma Celsius the temperature rises.
Furthermore, a neodymium magnet is under strain during operation of the magnetic coupling. This implies that irreversible demagnetization will occur long earlier than the Curie level has been reached, which typically limits using Neodymium-based magnetic coupling to temperatures under 150°C.
If higher temperatures are required, magnetic couplings manufactured from Samarium Cobalt magnets (SmCo) are usually used. SmCo isn’t as เกจวัดแรงดันpsi as Neodymium magnets however can work as much as 350°C. Furthermore, the temperature coefficient of SmCo is only 0,04% per diploma Celsius which signifies that it can be utilized in functions where efficiency stability is needed over a bigger temperature interval.
New technology 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 would broaden the working temperature space to reach temperatures of molten salts around 600°C. By exchanging the inner drive with a magnetic material containing the next Curie level and boosting the magnetic subject of the outer drive with particular magnetic designs; it was potential to develop a magnetic coupling that began at a lower torque degree at room temperature, but solely had a minor discount in torque level 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 may be seen in Figure 1, the place it’s proven that the torque level of the High Hot drives has been tested up to 590°C on the inner drive and nonetheless performed with an virtually linear discount in torque.
The graph additionally exhibits 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 efficiency stability is important over a larger temperature interval.
Conclusion At Sintex, the R&D department is still growing on the expertise, however they have to be challenged on torque degree at both totally different temperature, dimensions of the magnetic coupling or new purposes that haven’t beforehand been attainable with standard magnetic couplings, in order to harvest the complete potential of the High Hot know-how.
The High Hot coupling is not seen as a standardized shelf product, however as an alternative as custom-built by which is optimized for specific applications. Therefore, further development will be made in close collaboration with new partners.