NSK Europe, the European arm of Japanese bearing manufacturer NSK, has developed deep groove ball bearings that do not require external lubrication to be used in submersible pumps handling cryogenic gases corresponding to hydrogen and LNG.
NSK has developed special shaft bearings with a cage produced from self-lubricating fluoroplastic for submersible pumps that handle cryogenic gases and liquids.
The stainless-steel bearings with a cage manufactured from self-lubricating fluoroplastic are seeing increasing adoption in submersible pumps as a growing variety of tasks promote the use of hydrogen as an power source. These initiatives usually use special submersible pumps that can reliably pump gaseous and liquid media in steady or intermittent operation at low temperatures right down to around -200°C.
In such pumps, the double bearing of the pump shaft is a crucial design element. Corrosion resistance is crucial, and no lubricant can be utilized apart from the media washing around the bearing. However, this places robust demands on the material pairing.
So NSK has developed a sequence of deep groove ball bearings particularly for these exceptional operating circumstances, and a quantity of other key design options provide differentiation from conventional pump bearings. For example, the inner and outer rings are made from a stainless-steel adapted to the special necessities of rolling bearings.
A stable cage that occupies the complete inside quantity of the bearing provides guidance for the rolling elements (also made from stainless steel), whereas the cage material, a self-lubricating fluoroplastic, ensures low friction running of the bearing with out external lubrication. In Guaranteed , the high-performance fluoroplastic is extraordinarily wear-resistant and offers good low-temperature properties at speeds as much as 3600 rpm. The cage has a two-piece design, with the 2 halves joined by chrome steel rivets.
The NSK bearings are available in numerous sizes (shaft diameter 30–100 mm) and are designed for use in both larger hydrogen pumping facilities and decentralised applications, such as hydrogen filling stations.
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