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steam gets trapped in the line and prevents new condensate from actuating
the trap. The condensate will back up into the turbine until the steam in the
line condenses. If it is impossible to locate the steam trap near the turbine,
use a trap that has a steam lock release valve.
3.12 Located below the turbine. The steam trap will not actuate until the
condensate reaches the trap. If the steam trap is elevated this will not occur
until the equipment is already partially flooded.
3.13 Important note: In most cases the bore of the turbine will be greater in
diameter than the seal face OD until the throat expands into the case. This
makes it easy for condensate that forms at the seals to drain back into
the turbine case. However, in some cases the diameter steps down. This
prevents condensate that forms at the seal faces from draining back into
the case. Instead, it pools around the seal faces at bottom dead center.
To prevent this from occurring the turbine geometry should be modified to
provide drainage into the case or separate steam traps should be applied
directly at the seals in addition to the trap provided at the case drain.
4
Inspection of Steam Turbine Components
4.1
Remove the rotor element from the steam turbine.
4.2
Remove coupling, thrust bearing, speed pickup, slinger, etc. from the rotor
assembly.
4.3
Inspect the seal assembly drawing and confirm the turbine dimensions
shown. See Figure 1.
4.4
Inspect the areas of all sealing surfaces. This includes the areas near the
flange gaskets 18 and sleeve gaskets 19 . See Figure 2. These areas
must be free from any large pits, corrosion, or steam erosion. Any damage
in these areas must be repaired to insure proper sealing of the static
gaskets.
4.5
Hand polish the shaft to remove any burrs or buildup of deposits. Any
damage in the seal areas should be repaired or the shaft replaced prior to
seal installation.
5
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