This website uses cookies to ensure users have the best online experience. By continuing to browse this website, you are giving your consent to the use of cookies. To learn more, read our privacy policy. X
< Back to Dry Gas Seals

Type 28AT

Non-contacting Gas Seal for Turbo Compressors

Type 28AT: The original gas seal, with a design pedigree stretching back over 30 years and evolving gradually, installed and proven in thousands of compressors all around the world and remaining the preferred seal choice for many customers. Type 28 compressor dry-running gas seals have been the industry standard since early 1970 for gas-handling turbomachinery. Utilizing John Crane’s patented spiral groove pattern, these seals are non-contacting in operation. During dynamic operation, the mating ring/seat and primary ring/face maintain a sealing gap of approximately 0.0002"/5 microns, thereby eliminating wear. These seals eliminate seal oil contamination and reduce maintenance costs and downtime. Single, tandem and double seal arrangements are available.

Find out about AURA™; the next generation of gas seals from John Crane >

View complete list of product documents in all languages >


  • Cartridge design
  • Unidirectional or bidirectional capability
  • Single, double-opposed or tandem configuration
  • Robust design with unparalleled field-proven pedigree

Note: John Crane may validate individual seals for applications outside one or more of the parameter limits.


Temperature Limits

-4°F to 392°F/-20°C to 200°C, dependent on overall duty conditions

Pressure Limits

1,450 psi(g)/100 bar(g)

Speed Limits


Size Limits


Recommended Applications

  • Centrifugal Compressors
  • Other Compressors

I have a question about the [Product Name]:

{0} must be filled in.
{0} must be filled in.
{0} must be filled in.
{0} must be filled in.
{0} must be filled in.