Page 411 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Steam Turbines and T-rs 309

(45). The reversing blade assembly is positioned between the two rotor
disks and is bolted to the nozzle ring. The reversing blade assembly is
positioned by spacers and requires no further adjustment.

Dlsassembly

1. Remove the rotor assembly as outlined in Removal Section.
2. Remove the bolts (38, Figure 8-5), lockwashers (39), and spacers (40),
and lift out the reversing blade assembly (37). Mark each spacer (40)
so that it may be returned to its original location.
3. Remove the nozzle ring bolts (34 and 36), lockwashers (35) and
nozzle ring (33) from the casing.

Clearances

The clearance between the nozzle ring (33, Figue 8-5) and the shroud
on the first rotor disk (44) must be checked whenever the rotor assembly,
nozzle ring or reversing blade assembly is replaced. This clearance is a
minimum of .042 in. (1.07 mm) and a maximum of .072 in. (1.83 mm).
The clearance can be measured with a feeler gauge.

Adjustments
Inspect the nozzle ring and reversing blade assembly annually. Clean
scale or boiler compound deposits as necessary. Replace eroded parts.

Assembly and Replacement
1. Clean the casing and nozzle ring sealing surfaces.
2. Apply a thin coat of paste type sealer and plastic string compound to
the nozzle ring sealii surface on the steam end turbine casing (Refer-
ence Figure 8-8).
3. Apply anti-galling compound to the threads of the nozzle ring bolts
(34 and 36, Figure 8-5).
4. Bolt the nozzle ring to the turbine casing. Be sure that lockwashers
(35) are used with all bolts.
5. Place lockwashers (39) on the reversing blade assembly bolts (38)
and apply anti-galling compound to the bolt threads. Put the bolts
through the holes in the reversing blade assembly and slip the spac-
ers (40) over the bolts.
6. Position the reversing blade assembly (37) in the turbine casing and
bolt it to the nozzle ring (33).

Note: Be sure the reversing blade assembly is installed in the same
location from which it was removed so that it covers all the