Magnetic coupling at elevated temperatures

Magnetic couplings are utilized in many functions within pump, chemical, pharmaceutical, process and security industries. They are usually used with the aim of decreasing put on, sealing of liquids from the surroundings, cleanliness wants or as a security factor to brake over if torque suddenly rises.
The commonest magnetic couplings are made with an outer and inside drive, both construct up with Neodymium magnets so as to get the very best torque density as potential. By optimizing the diameter, air gap, magnet dimension, variety of poles and selection of magnet grade, it’s attainable to design a magnetic coupling that suits any utility in the vary from few millinewton meter up to a number of hundred newton meters.
When solely optimizing for prime torque, the designers typically are most likely to overlook considering the influence of temperature. If the designer refers to the Curie point of the person magnets, he’ll claim that a Neodymium magnet would fulfill the requirements as a lot as more than 300°C. Concurrently, it may be very important include 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 generally limits the use of 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 strong as Neodymium magnets but can work up to 350°C. Furthermore, the temperature coefficient of SmCo is only 0,04% per diploma Celsius which implies that it might be utilized in functions the place efficiency 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 brand new technology 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 could broaden the working temperature space to achieve temperatures of molten salts round 600°C. By exchanging เกจวัดแรงดัน with a magnetic material containing a higher Curie point and boosting the magnetic subject of the outer drive with particular magnetic designs; it was attainable to develop a magnetic coupling that started 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 in opposition to 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 examined up to 590°C on the inside drive and nonetheless 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 decrease temperature market the place efficiency stability is necessary over a larger temperature interval.
Conclusion At Sintex, the R&D department is still creating on the expertise, however they must be challenged on torque degree at both different temperature, dimensions of the magnetic coupling or new purposes that haven’t previously been possible with commonplace magnetic couplings, in order to harvest the complete potential of the High Hot know-how.
The High Hot coupling just isn’t seen as a standardized shelf product, but as an alternative as custom-built by which is optimized for particular functions. Therefore, further growth will be made in shut collaboration with new companions.
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