Close Tolerance Bayonet

A close tolerance bayonet is a vital component in vacuum insulated cryogenic piping systems. It ensures a tight connection between inner and outer pipes, minimizing heat transfer and maintaining the required low temperature environment. By reducing thermal conduction, it optimizes insulation performance and acts as a barrier, creating a vacuum-sealed space that minimizes heat transfer through conduction, convection, and radiation. 

Additionally, the close tolerance design prevents leaks, offering a precise metal to metal seal that minimizes the risk of cryogenic fluid escape. Other advantages include eliminating the need for elastomer O-rings or PTFE gasket as sealing material at cryogenic temperature. Both materials in essence are not suitable for cryogenic use due to its unfavorable thermal expansion coefficient at cryogenic temperature. Elastomer O-ring when exposed cryogenic temperature will become brittle and lose its sealing capability. Broken O-ring or PTFE material shading are major root cause for cryogenic fluids contamination and causing blockage and failure to downstream instruments and equipment. 

Feature and Benefits

  • Eliminate the need for elastomer O-ring and PTFE material for sealing
  • Lowest heat leak in its class
  • Extremely close tolerance design to minimize convective and conductive heat transfer
  • Higher heat barrier factor, eliminate condensation or frosting at clamp joints
  • Installation flexibility, suitable for any installation position, vertical or horizontal
  • Bi-directional flow direction

To gain a comprehensive understanding of the differences between high-quality and low-quality bayonet connections, click on the link below:

Close Tolerance Bayonet (

Product Cutsheet:

Bayonet Connection.pdf 

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