Shafts, rotating, sealing labyrinth seals

Damage to the labyrinth requires replacement of the expander heat barrier or compressor shaft seal. A replacement design (Figure 5-6) uses a replaceable stainless-steel labyrinth mounted on the shaft. Because the seal is not tapered, axial movement of the shaft has little or no measurable effect on seal gas flowrates. Each labyrinth has an integral oil slinger incorporated into the design. Also, each rotating... 

Dry-friction whiri. This type of whip is experienced when the surface of a rotating shaft comes into contact with an unlubricated stationary guide. The effect takes place because of an unlubricated journal, contact in radial clearance of labyrinth seals, and loss of clearance in hydrodynamic bearings. 

Seals for rotating or sliding shafts use elements of PTFE compounded with fillers such as graphite. Fillers must have the chemical resistance for the service conditions that will be eneountered. Labyrinth seals that do not contact the shaft depend on a tortuous interface, fluid surface tension, and a pump-Uke design to prevent leakage. 

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