NSK Europe, the European arm of Japanese bearing manufacturer NSK, has developed deep groove ball bearings that don’t 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 made 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 rising adoption in submersible pumps as a growing number of tasks promote using hydrogen as an energy supply. These projects typically use particular 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 important design component. Corrosion resistance is essential, and no lubricant can be utilized apart from the media washing across the bearing. However, pressure gauge calls for on the fabric pairing.
So NSK has developed a sequence of deep groove ball bearings specifically for these distinctive operating conditions, and a number of other key design options present differentiation from typical pump bearings. For instance, the internal and outer rings are manufactured from a chrome steel adapted to the special requirements of rolling bearings.
A steady cage that occupies the entire inside quantity of the bearing supplies steering for the rolling parts (also made of stainless steel), whereas the cage material, a self-lubricating fluoroplastic, ensures low friction working of the bearing without external lubrication. In addition, the high-performance fluoroplastic is extraordinarily wear-resistant and provides good low-temperature properties at speeds as much as 3600 rpm. The cage has a two-piece design, with the two halves joined by stainless steel rivets.
The NSK bearings can be found in numerous 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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