Type 670 Metal Bellows Seals | Pump Seals | John Crane

Type 670

Low-temperature, All-Alloy C-276 Metal Bellows Shaft Seal for Highly Corrosive Fluids

The Type 670 is an all-Alloy C-276 rotating bellows seal, providing high strength and excellent corrosion resistance. It is extremely durable in applications where temperature and media (fluid) result in an aggressive environment. The Type 670 has been tested per API-682 Type B seals for low-temperature refinery services. Other common applications include acids, caustics, amines and products with H2S, such as sour water and sour hydrocarbons. The Type 670 can be shaft-mounted or is available in both dual and single cartridge arrangements. In dual seal arrangements a non-pressurized buffer or pressurized barrier fluid can be used. A pumping ring recirculates barrier fluid, assuring cooler operating temperatures and extended reliable performance.



  • California Residents: PROPOSITION 65 WARNING
  • Static secondary seal — available in single or dual arrangements, shaft mounted or in a cartridge; manufactured with a 45-degree tilt edge at the bellows' inside diameter to disperse stresses and maximize operating life.
  • Superior nesting ripple plate shape with a three-sweep radius; this plate design allows the bellows device to be flexed repeatedly without the metal being stressed beyond its endurance limit.
  • Self-cleaning design — rotating bellows throw off suspended particles that clog spring-type seals. This self-cleaning action eliminates the need for external flushing, filters or cyclone separators and their associated costs.
  • World-class bellows manufacture — our bellows production facility has an outstanding manufacturing process with state-of-the-art stamping, welding and testing technology.
  • The bellows incorporate all of the design features resulting from key engineering competencies, such as metallic thin shell methodology, tribology and fluid sealing technology, and thin film/fluid mechanics.

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