Magnetic coupling at elevated temperatures

Magnetic couplings are used in many purposes within pump, chemical, pharmaceutical, course of and safety industries. pressure gauge วัด แรง ดัน น้ำ are sometimes used with the aim of decreasing put on, sealing of liquids from the setting, cleanliness needs or as a safety factor to brake over if torque all of a sudden rises.
The most typical magnetic couplings are made with an outer and inner drive, both construct up with Neodymium magnets in order to get the highest torque density as potential. By optimizing the diameter, air gap, magnet measurement, variety of poles and choice of magnet grade, it is possible to design a magnetic coupling that fits any utility in the vary from few millinewton meter as much as several hundred newton meters.
When solely optimizing for top torque, the designers often tend to forget contemplating the influence of temperature. If the designer refers back to the Curie level of the individual magnets, he will declare that a Neodymium magnet would fulfill the necessities up to more than 300°C. Concurrently, it could be very important embody the temperature dependencies on the remanence, which is seen as a reversible loss – usually round 0,11% per diploma Celsius the temperature rises.
Furthermore, a neodymium magnet is beneath stress throughout operation of the magnetic coupling. This means that irreversible demagnetization will occur long before the Curie level has been reached, which generally limits the usage of Neodymium-based magnetic coupling to temperatures under 150°C.
If greater temperatures are required, magnetic couplings made from Samarium Cobalt magnets (SmCo) are typically used. SmCo is not as robust as Neodymium magnets but can work up to 350°C. Furthermore, the temperature coefficient of SmCo is only zero,04% per diploma Celsius which implies that it can be used in functions where performance 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 new era of magnetic couplings has been developed by Sintex with help from the Danish Innovation Foundation.
The objective of the venture was to develop a magnetic coupling that could expand the working temperature space to achieve temperatures of molten salts around 600°C. By exchanging the inside drive with a magnetic material containing the next Curie point and boosting the magnetic subject of the outer drive with special magnetic designs; it was potential to develop a magnetic coupling that started at a decrease torque stage at room temperature, however only had a minor discount in torque stage as a function of temperature. This resulted in superior efficiency above 160°C, irrespective 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 stage of the High Hot drives has been examined as a lot as 590°C on the inside drive and still carried out with an nearly linear reduction in torque.
The graph also 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 performance stability is essential over a bigger temperature interval.
Conclusion At Sintex, the R&D department remains to be developing on the know-how, but they need to be challenged on torque degree at either totally different temperature, dimensions of the magnetic coupling or new functions that haven’t beforehand been attainable with normal magnetic couplings, so as to harvest the full potential of the High Hot technology.
The High Hot coupling isn’t seen as a standardized shelf product, but as an alternative as custom-built by which is optimized for specific purposes. Therefore, further development will be made in shut collaboration with new partners.
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