Magnetic couplings are utilized in many purposes within pump, chemical, pharmaceutical, process and security industries. They are usually used with the purpose of lowering wear, sealing of liquids from the environment, cleanliness needs or as a safety issue to brake over if torque suddenly rises.
The most common magnetic couplings are made with an outer and inner drive, both construct up with Neodymium magnets so as to get the best torque density as possible. By optimizing pressure gauge , air gap, magnet size, variety of poles and choice of magnet grade, it is possible to design a magnetic coupling that suits any application in the range from few millinewton meter up to several hundred newton meters.
When solely optimizing for high torque, the designers usually are likely to overlook considering the affect of temperature. If the designer refers to the Curie point of the person magnets, he’ll claim that a Neodymium magnet would fulfill the necessities as much as more than 300°C. Concurrently, you will need to include the temperature dependencies on the remanence, which is seen as a reversible loss – usually round 0,11% per degree Celsius the temperature rises.
Furthermore, a neodymium magnet is under pressure during operation of the magnetic coupling. This implies that irreversible demagnetization will occur lengthy earlier than the Curie point has been reached, which usually limits the utilization of Neodymium-based magnetic coupling to temperatures under 150°C.
If higher temperatures are required, magnetic couplings made of Samarium Cobalt magnets (SmCo) are sometimes used. SmCo just isn’t as robust as Neodymium magnets but can work as much as 350°C. Furthermore, the temperature coefficient of SmCo is just zero,04% per degree Celsius which implies that it could be utilized in purposes the place efficiency stability is needed 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.
pressure gauge of the venture was to develop a magnetic coupling that might expand the working temperature space to succeed in temperatures of molten salts round 600°C. By exchanging the inside drive with a magnetic material containing a better Curie point and boosting the magnetic subject of the outer drive with special magnetic designs; it was possible to develop a magnetic coupling that began at a decrease torque level at room temperature, however solely had a minor discount in torque degree as a operate of temperature. diaphragm seal resulted in superior performance above 160°C, irrespective of if the benchmark was against a Neodymium- or Samarium Cobalt-based system. This may be seen in Figure 1, where it’s 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 virtually linear discount 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 where efficiency stability is important over a bigger temperature interval.
Conclusion At Sintex, the R&D division remains to be developing on the know-how, however they have to be challenged on torque level at either totally different temperature, dimensions of the magnetic coupling or new applications that have not beforehand been potential with commonplace magnetic couplings, so as to harvest the total potential of the High Hot expertise.
The High Hot coupling isn’t seen as a standardized shelf product, however instead as custom-built by which is optimized for particular purposes. Therefore, further development shall be made in shut collaboration with new companions.