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5.15 Install the socket headed cap screws 40-2 to secure the seals to
the turbine. Use the same torque as that specified by the turbine
manufacturer for the carbon box.
5.16 Loosen the screws 40-1 securing the setting plates 103 by
1/2 turn. This will reduce the binding between the setting plate and
the sleeve and make it easier to rotate the rotor as required in the
following steps.
5.17 Tighten the sleeve gasket compression screws 40 in the
drive collars 58 . Tighten all screws evenly to insure
uniform compression of the sleeve gaskets. Rotate the
rotor assembly to access the screws.
5.18 Tighten the drive collar set screws 57 to secure the seal assem-
blies to the shaft. Use a torque of 17.6 N-m (156 in-lbf).
5.19 Remove the setting plate screws 40-1 and remove the setting
plates. Keep the setting plates and screws for future use.
5.20 Proceed to warm up the turbine slowly.
5.21 Start the turbine. Usually, there should not be any visible leakage
past the seals during normal operation. In a cold climate, some
steam leakage may be visible.
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Testing of Turbine with Seals
After installing GTS seals in a turbine, static and dynamic testing under
air or steam pressure is recommended. Safety precautions for pressur-
ized equipment should be followed at all times. Note that if GTS seals
are exposed to a slug of water they will leak more until the water has
dissipated.
6.1 Seal the turbine case exhaust and inlet with flanges rated for at
least 345 kPa (50 psig) or the desired back pressure. Connect a
pressure source and provide a pressure indicator rated for 345 kPa
or the desired back pressure.
6.2 Pressurize the turbine case to 344 kPa (50 psig) with no shaft
rotation to test static leakage. GTS seals faces lift off with
pressure so some leakage is normal. Isolate the turbine case
from the pressure source and monitor the pressure decay.
Typical pressure decay over a minute is 69 -103 kPa (10 -15 psig).
A slight hissing sound may be audible from the GTS seals.
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