Page 55 - Compression Machinery for Oil and Gas

46 SECTION II Types of Equipment

FIG. 3.15 Dry gas seal supply and vent ports.

Impellers
Hub
attachment

Thrust bearing
Radial bearing
Radial bearing
runner
FIG. 3.16 Impeller shaft assembly. (Based on TRIZ, 2018, http://triz-ltd.com/en/produktsiya/
rotora/.)

Shaft
The rotating assembly will typically consist of a shaft with mounted impellers,
sleeves, seal components, thrust disk, and a coupling hub as shown in Fig. 3.16.
The shaft is sized to safely transmit torque from the coupling to the impellers,
and if necessary, to additional bodies attached at the nondrive end. Shaft design
further considers torsional and lateral rotordynamics, as well as material selec-
tion and processing for environmental conditions.
Most shafts are manufactured from a single piece of forged alloy steel or bar
stock that is heat treated and stress relieved. Typical materials include 4140 and
4340 steels. Unique applications require different grades of steel. Ultralow