Bearing seals labyrinth seal

Two or four lobe bearings are used in these expanders, determined by the funetion of the rotor-dynamie requirements. A double-aeting thrust bearing may be mounted, if required. Labyrinth seals with eonneetions for seal gas are standard equipment, however, dry gas seals are available. 

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. 

Oil, used for lubricating the gears and bearings, is separated from the compressed airstream by labyrinth seals. Shown in Figure 3.31, the seals consist of two separate components, an air seal and an oil seal. In between the two, the seal is open to atmosphere. Any oil bypassing the oil seal leaks to atmosphere. The air seal is always at a higher pressure so that any leaks are always from air to atmosphere and oil cannot enter the process fluid. Oil is typically provided by a shaft-driven pump with a standby motor-driven pump available. 

Inlet nozzle Outlet nozzle Outer housing Inlet housing Stationary blade carrier Screw bolts Sheet plate envelope Radial bearing 3-stage labyrinth seal Floating ring seal and stillstand seal Labyrinth chambers... 

Any piece of rotating equipment experiencing excessive vibration should be taken out of service before additional damage is done to its seals, bearings, or labyrinths. One quick way to determine the magnitude of the problem is to stand a nickel on its edge on the pump or compressor case. If the coin cannot maintain its balance, there is a good chance that vibration is too excessive to permit safe continued operation. 

These bearings are made with either straight or spherical OD outer rings, are usually prelubricated with grease, and have double integral contact or labyrinth seals or shields. 

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