Page 355 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

334 Major Process EQuipment Maintenance and Repair

Revlew of Turbine Hardware

The steam turbine is a comparatively simple type of prime mover. It
has only one major moving part, the rotor which carries the buckets or
blades. These, with the stationary nozzles or blades, form the steam path
through the turbine. The rotor is mounted on a shaft supported on journal
bearings, and axially positioned by a thrust bearing. A housing with
steam inlet and outlet connections surrounds the rotating parts and serves
as a frame for the unit.
However, a great number of factors enter into the design of a modern tur-
bine, and its present perfection is the result of many years of research and
development. The following is a listing of special purpose turbine “hard-
ware” as shown in Figure 8-2.

1. High pressure parts.
a. Trip valve-trip and throttle.
b. Governor valve(s).
c. Steam chest, nozzle bowl, chamber or box.
d. Nozzles-rings and diaphragms.

2. Low pressure parts.

a. Casing or cylinder.
b. Blade rings and covers.
c. Exhaust hood.
d. Glands or seals.

3. Rotor assembly.

a. Blades or buckets.
b. Disk(s).
c. Shaft or drum.
Bearings.
Thrust control mechanism.

4. Auxiliaries.

a. Overspeed trip device.
b. Governor.
c. Turning gear.