Sealing cryogenics



Cryogenics are identified as extremely cold fluids that seldom present a corrosion problem, but do present at least five other problems to mechanical seals:

  • The product is too cold for an O-ring or any other type of elastomer.
  • Many cryogenic fluids are non-lubricants. A special carbon graphite seal face is used in these applications that has some organic material embedded in the mixture that will release the graphite to provide a lubricating film.
  • Cold fluids freeze the moisture in the atmosphere outboard the seal and restrict the seal movement.
  • The seal faces must be dried prior to installing the seal, or any lubricant or moisture on the faces will freeze.
  • The cryogenic is often dangerous.
Applying an environmental control that would heat the cryogenic fluid would not be sensible.

A tandem metal bellows seal application with an anti-freeze type barrier or buffer fluid is your best bet.

The bellows seal will allow you to eliminate all elastomers from the application.

The bellows seals can be sleeve mounted with stainless steel gaskets to eliminate all elastomers and plastics

You can choose between rotating and stationary bellows, but be sure whichever one you choose has adequate vibration damping installed to prevent “slip stick” vibration problems.