Page 457 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Steam Turbines and Turboexpanders 435

Disassernbllng Turboexpanders

The modular design approach followed by many manufacturers allows
us to disassemble turboexpanders into major subassemblies or modules.
With this concept the machine separates into three major components:
expander case, rotating section, and compressor case. This eliminates the
necessity of total disassembly when the main concern is isolated in one of
the three primary areas. To separate the system into major components refer
to Figure 8-25 and proceed as follows:*

1. Support the compressor inlet spacer (196) with a hoist or forklift.
Remove screws (401). Remove compressor inlet spacer (196).
2. Support bearing housing (147). Remove screws (423). Slide away
compressor section (188). Take care not to bump the compressor
impeller (170). Remove O-ring (430). Remove retaining screw
(179) and retaining washer (180). Use a jack screw to remove com-
pressor impeller (170). Do not use any other tool or device to re-
move this wheel. Remove keys (421).
3. With the bearing housing (147) still under support with a hoist or
crane, remove screws (440). Carefully withdraw the entire rotating
section. Remove seal (966). Take care not to bump the expander
rotor (107). Remove the rotating section to a clean work area.

Note: The machine is now separated into three major components. In this
mode the variable nozzle assentbly remains attached to the expander
case. For further disassembly of the major components see the appropri-
ate section in the following procedures.

These instructions describe the total disassembly of the machine.
Compressor Case and Impeller

I. Disconnect compressor process piping and instrumentation lines.
2. Support compressor inlet spacer (196) with a hoist. Remove socket
head cap screws (401), compressor inlet spacer (196), and O-ring
(405).
3. If the assembly includes a transition piece between parts (196) and
(188), remove all fasteners. Also, if there is a shear ring or split-
ring spacer, remove screws and remove this part, or parts.

* Figure 8-25 represents a typical Rotoflow expander and may differ from other manufacturers’
equipment.