Do Not Freeze

into Cryogenic Applications Sealing Solutions

Cryogenic Sealing Solutions
 provide a strong sealing mechanism for materials held at cryogenic temperatures, such as cryogenic fluids. Most commonly used are liquid helium and liquid nitrogen, which boil at very low temperatures, below −153°C (120K), as well as hydrocarbons with low freezing points and refrigerating mixtures.

Typically, applications where temperatures fall below -238°F (or -150°C)  to absolute zero which is -460°F (or -273°C) are considered cryogenic.

Cryogenic seals are used in a variety of applications.  These include:

  • LNG fueling systems and compressors
  • rocket propulsion filling systems
  • specialty gas manufacturing
  • scientific instrumentation
  • magnetic resonance imaging
  • infrared telescopes
  • radio astronomy
  • biosystems
  • satellite tracking systems
  • pharmaceutical research

Cryogenic fluids include liquid oxygen, liquid hydrogen, liquid helium, hydrocarbons that have very low freezing points, refrigerants, and coolants.  In fact, cryogenics can be traced back to the 1800s and the first use of refrigerants.

For extreme cryogenic application, the seal faces and components may need to be completely dried before installation or you run the risk of the faces freezing together.  As a result, lubricants may be prohibited, which means that an unfilled PTFE should be preferred. Also, any moisture near the area of the fluid will freeze, which can even cause problems for the space within the seal, or between the clamp ring and the gland.

There are many benefits to using polymers such as PTFE materials for cryogenic seals.  In applications such as aerospace, their high strength-to-weight ratios mean significant reductions in weight compared to using all metal seals.  Their low thermal conductivities acts as insulators.  Polymers are corrosion resistant, and many (such as PTFE) has self-lubricating properties.  In addition, polymers have a reputation for being durable and fatigue resistant.  All of these characteristics are extremely useful for cryogenic seals.

The demand for seals for use in cryogenics applications is increasing.