NSK Europe, the European arm of Japanese bearing manufacturer NSK, has developed deep groove ball bearings that do not require external lubrication for use in submersible pumps dealing with cryogenic gases similar to hydrogen and LNG.
NSK has developed particular shaft bearings with a cage made from self-lubricating fluoroplastic for submersible pumps that deal with cryogenic gases and liquids.
diaphragm seal -steel bearings with a cage made from self-lubricating fluoroplastic are seeing growing adoption in submersible pumps as a rising number of projects promote the usage of hydrogen as an power supply. These projects usually use particular submersible pumps that can reliably pump gaseous and liquid media in continuous or intermittent operation at low temperatures right down to round -200°C.
In such pumps, the double bearing of the pump shaft is a crucial design factor. Corrosion resistance is crucial, and no lubricant can be used apart from the media washing around the bearing. However, this locations robust demands on the material pairing.
So NSK has developed a series of deep groove ball bearings particularly for these exceptional working circumstances, and several key design features present differentiation from standard pump bearings. For instance, the internal and outer rings are made from a chrome steel tailored to the particular requirements of rolling bearings.
A stable cage that occupies the whole inside volume of the bearing supplies guidance for the rolling components (also made of stainless steel), while the cage material, a self-lubricating fluoroplastic, ensures low friction running of the bearing with out external lubrication. In addition, the high-performance fluoroplastic is extraordinarily wear-resistant and presents good low-temperature properties at speeds up to 3600 rpm. The cage has a two-piece design, with the 2 halves joined by stainless-steel rivets.
The NSK bearings can be found in various sizes (shaft diameter 30–100 mm) and are designed to be used in each larger hydrogen pumping amenities and decentralised functions, such as hydrogen filling stations.
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