General
The 9HA.01 gas turbine unit has two double tilting pad
journal bearings which support the gas turbine rotor and two self-equalizing
tilting pad thrust bearings to maintain the rotor-to-stator axial position.
These bearings are incorporated in the inlet casing and exhaust frame which are
supplied oil from the main lubricating oil system.
Lubrication
The main turbine bearings are pressure-lubricated with oil
supplied, from the oil reservoir. Oil feed piping where practical, is run
within the lube oil drain lines, or drain channels, as a protective measure. In
the event of a supply line leak, oil will not be sprayed on nearby equipment,
thus eliminating a potential safety hazard.
The oil flows through branch lines to an inlet in each
bearing housing. When the oil enters the housing inlet, flows into an annulus
around the bearing. From the annulus, the oil flows through machined holes or
slots to the bearing rotor interface.
Lubricant Sealing
Oil on the surface of the turbine shaft is prevented from
being spun along the shaft by oil seals in each of the bearing housings. These
labyrinth seals are assembled at the extremities of the bearing assemblies
where oil control is required. A smooth surface is machined on the shaft and
the seals are assembled so that only a small clearance exists between the oil
seals and the shaft. The oil seals are designed with tandem rows of teeth and
an annular space between them. Pressurized sealing air is admitted into this
space to prevent lubrication oil reservoir is vented to atmosphere after
passing through an oil vapor extractor.
Load Coupling
A rigid, hollow coupling connects the forward compressor
rotor shaft to the generator. A bolted flange connection forms the joint at
each end of the coupling.
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