Type 28AT
Manufacturer: John Crane

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.
• 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 LIMITS4°F to 392°F/ 20°C to 200°C, dependent on overall duty conditions
PRESSURE LIMITS1,450 psi(g)/100 bar(g)
SPEED LIMITS394fps/120m/s
SIZE LIMITS12.125"/308mm