Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many purposes inside pump, chemical, pharmaceutical, process and security industries. They are sometimes used with the purpose of lowering wear, sealing of liquids from the surroundings, cleanliness needs or as a security factor to brake over if torque all of a sudden rises.
The most typical magnetic couplings are made with an outer and inside drive, each construct up with Neodymium magnets in order to get the highest torque density as possible. By optimizing pressure gauge หน้าปัด 2 นิ้ว , air gap, magnet measurement, number of poles and selection of magnet grade, it’s potential to design a magnetic coupling that suits any application within the vary from few millinewton meter up to several hundred newton meters.
When solely optimizing for high torque, the designers typically are inclined to neglect considering the affect of temperature. If the designer refers to the Curie level of the person magnets, he’ll claim that a Neodymium magnet would fulfill the necessities as much as greater than 300°C. Concurrently, it is very important embody the temperature dependencies on the remanence, which is seen as a reversible loss – typically round 0,11% per degree Celsius the temperature rises.
Furthermore, a neodymium magnet is under strain during operation of the magnetic coupling. This implies that irreversible demagnetization will happen lengthy earlier than the Curie level has been reached, which usually limits the use of Neodymium-based magnetic coupling to temperatures beneath 150°C.
If higher temperatures are required, magnetic couplings made from Samarium Cobalt magnets (SmCo) are usually used. SmCo just isn’t as sturdy as Neodymium magnets however can work as much as 350°C. Furthermore, the temperature coefficient of SmCo is simply 0,04% per degree Celsius which signifies that it can be used in functions the place performance stability is needed over a larger 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 help from the Danish Innovation Foundation.
The purpose of the venture was to develop a magnetic coupling that might broaden the working temperature space to achieve temperatures of molten salts round 600°C. By exchanging the inner drive with a magnetic materials containing a better Curie level and boosting the magnetic field of the outer drive with particular magnetic designs; it was potential to develop a magnetic coupling that began at a decrease torque level at room temperature, but solely had a minor discount in torque degree as a operate 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 may be seen in Figure 1, the place it is shown that the torque stage of the High Hot drives has been tested as a lot as 590°C on the internal drive and still carried out with an almost linear reduction in torque.
The graph additionally reveals that the temperature coefficient of the High Hot coupling is even decrease than for the SmCo-system, which opens a lower temperature market the place performance stability is necessary over a larger temperature interval.
Conclusion At Sintex, the R&D division is still growing on the expertise, but they need to be challenged on torque level at both completely different temperature, dimensions of the magnetic coupling or new purposes that have not previously been attainable with commonplace magnetic couplings, in order to harvest the complete potential of the High Hot know-how.
The High Hot coupling isn’t seen as a standardized shelf product, but as a substitute as custom-built by which is optimized for specific applications. Therefore, further improvement will be made in shut collaboration with new partners.