NSK develops self-lubricating deep groove ball bearings for submersible pumps in cryogenic applications

For use in submersible pumps that handle cryogenic gases such as hydrogen and LNG, NSK has developed bearings that do not require external lubrication. These stainless steel bearings with a self-lubricating fluoroplastic cage are increasingly being adopted in submersible pumps from leading manufacturers.

A growing number of projects around the world are now promoting the use of hydrogen as an energy source. These projects often use special submersible pumps that can reliably pump gaseous and liquid media in continuous or intermittent operation – at low temperatures down to around -200°C.

In such pumps, the double bearing of the pump shaft is a critical design feature. Corrosion resistance is essential and no lubricants may be used other than wash media around the bearing. However, this tribology is unfavorable because it imposes strong constraints on the pairing of materials. In addition, the bearings must maintain a long service life, even at low temperatures.

NSK has therefore developed a series of deep groove ball bearings specifically for these exceptional operating conditions, where a number of key design features set them apart from conventional pump bearings. For example, the inner and outer rings are made of a stainless steel adapted to the specific requirements of the bearings.

A stable cage that occupies the entire internal volume of the bearing provides guidance for the rolling elements (also made of stainless steel), while the cage material, a self-lubricating fluoroplastic, ensures low-friction operation of the bearing without external lubrication. Additionally, the high-performance fluoroplastic is extremely hard-wearing and offers good low-temperature properties at speeds up to 3600 rpm. The cage is a two-piece design, with the two halves joined by stainless steel rivets. In laboratory tests and in practice, these deep groove ball bearings achieve a significantly longer service life than other bearings for this application, such as those with a hard phenolic resin cage.

NSK bearings are available in various sizes (30-100mm shaft diameter) and are ideal for use in large hydrogen pumping facilities and decentralized applications, such as hydrogen filling stations.

Of course, the bearings are also suitable for pumps handling other cryogenic gases such as nitrogen.

Press picture

NSK has developed special shaft bearings with a self-lubricating fluoroplastic cage for submersible pumps that handle cryogenic gases and liquids

On NSK Europe

NSK Europe Ltd. is the European organization of Tokyo-the bearing manufacturer NSK, which was founded in Japan in 1916 and today employs nearly 30,400 people in its global operations. The products and solutions offered by the industrial and automotive supplier can be found wherever things move. In addition to almost all types of bearings, the company’s portfolio includes ball bearings, linear technology, wheel bearing assemblies, transmission and motor bearings, and steering systems. The company is oriented towards perfection in all its business activities. Its goal is quality leadership in its industry, which it strives to achieve through a process of continuous improvement, excellent product development, optimized production processes and customer-oriented service processes. In fiscal year 2020, the more than 4,350 employees of NSK Europe Ltd. generated more sales 792 million euros.

www.nskeurope.com

NSK Deutschland GmbH

Harkortstrasse 15

40880 Ratingen

Germany

Pilat Marie-Dominique

Telephone: +49 2102 4811280

Fax: +49 2102 4812290

[email protected]

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