Type 48VBF | John Crane

Type 48VBF

Low leakage, high temperature shaft seal for uncooled boiler-feed-water

The Type 48VBF is a single seal that can operate without a cooling water system (external heat exchanger, API Plan 23) in critical high temperature pumps. In systems such as boiler feed water (hot, demineralized, deaerated water) for fossil-fuel steam power plants or within the utilities section of a process plant, can simplify operations and significantly reduce water consumption.

Marginally cooled or even uncooled, the Type 48VBF can run 20 °C hotter than competitive solutions, so will run longer in marginal conditions. Using advanced face technology and assembly techniques, unique “hydropads” allow the seal faces to remain flat in operation, increasing lubrication efficiency and so enabling the seal to run cooler.

The 48VBF is an easy upgrade from the existing John Crane 48V seal, requiring nothing more than changing the primary ring.



  • California Residents: PROPOSITION 65 WARNING
  • Plans such as 23 or 21 with heat exchangers are not required
  • Rotating mating ring design for reduced misalignment and higher shaft speed capability
  • Mating ring outer diameter surfaces entirely exposed to process fluid for enhanced heat transfer

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