pressure gauge 10 bar , the European arm of Japanese bearing manufacturer NSK, has developed deep groove ball bearings that don’t require external lubrication for use 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 made of self-lubricating fluoroplastic are seeing rising adoption in submersible pumps as a rising variety of initiatives promote the usage of hydrogen as an power supply. These projects often 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 critical design element. Corrosion resistance is essential, and no lubricant can be used apart from the media washing around the bearing. However, this places robust demands on the fabric pairing.
So NSK has developed a collection of deep groove ball bearings specifically for these distinctive operating situations, and several key design options present differentiation from typical pump bearings. For instance, the internal and outer rings are made of a stainless-steel adapted to the particular necessities of rolling bearings.
A steady cage that occupies the whole internal volume of the bearing provides steering for the rolling elements (also made from stainless steel), while the cage material, a self-lubricating fluoroplastic, ensures low friction operating of the bearing with out external lubrication. In addition, the high-performance fluoroplastic is extraordinarily wear-resistant and provides good low-temperature properties at speeds up to 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 both larger hydrogen pumping services and decentralised functions, corresponding to hydrogen filling stations.
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