Type 37FSB Split Seals | Pump Seals | John Crane

Type 37FSB

Heavy-duty Balanced Split Elastomer Bellows Seal for Agitators, Mixers and Pumps

The Type 37FSB fully split mechanical seal helps significantly reduce maintenance on larger, difficult-to-seal equipment. It is recommended for use on heavy-duty packed equipment that previously could not accommodate mechanical seals due to severe shaft runout and vibration, difficult disassembly, worn-out equipment and similar problems. Its outside-mounted design allows it to be used on both vertical and horizontal applications.

The mechanical seals are ideal for use on large, heavy-duty rotating shaft equipment such as mixers, agitators, and pumps. They are commonly found in the demanding pulp and paper, power generation, food and beverage, wastewater treatment and mining industries and are quickly and easily repairable, either on-site or at any John Crane Service Center.



  • California Residents: PROPOSITION 65 WARNING
  • The elastomer bellows compression ring provides extreme flexibility. Shaft deflections, angular misalignment, and run-outs are "tracked" by the seal without diminishing performance. Type 37FSB split seals solve shaft motion and vibration problems that prohibit use of other seal designs.
  • The compression ring acts as the spring, eliminating clogging problems seen in fibrous or abrasive services.
  • The wide sealing surface of the sealing ring prevents leaks even on the most worn, pitted shafts.
  • Rotating assembly self-aligns itself square with the shaft for true running.
  • Fewer parts and simple design allow for easy installation. Seal can be readily mounted on worn shafts and out-of-square stuffing boxes — no modification of equipment is needed.

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