BK Cooling Water

Multistage rotodynamic pumps equipped with product lubricated plain bearings

Industrial Processes

Industrial power generation processes are similar to those of large utility blocks. The power input, operator training, as well as the pumps are part of the end-user production process.  High reliability, ease of maintenance, low investment as well as operation costs are important criteria for the end-user.

Product Development

Sulzer engineering concentrated on developing and designing pumps to fulfill these needs. As an example Sulzer developed the magnetic lift-off device Permavor. Using this device eliminates complicated lube oil systems - which enabled us to improve availability significantly. Reducing maintenance as well as increasing operational safety is an important step in the evolution of pump engineering. This can be especially well done by eliminating the external bearings and reducing significantly the bearing span.

Multistage rotodynamic pumps have been traditionally equipped with oil-lubricated or antifriction bearings.  Newly developed materials for bearings such as:

• non-metallic materials e.g. PEEK
• Ceramics  e.g. Silicon Carbide (SiC)
• Special coatings e.g. SumeSol

now allow the use of product-lubricated bearings. By doing so the bearings are no longer installed externally to the hydraulic pump parts, surrounded and lubricated by the pumped fluid.  This technology has been used for more than 10 years in various pump types, multistage boiler feed pumps, vertical can pumps, magnetic driven pumps as well as pumps for reverse osmosis.

The results of prototype testing with product-lubricated bearings in multistage pumps, over a period of several years, have proven to be an excellent bearing design solution.