How to extend the service life of steam turbomachinery bearing?

Labyrinth isolators are stationary bearing protection devices used in steam turbomachinery turbines. They are designed to isolate the bearing from external pressures and moisture. The thermal expansion and contraction of steam causes condensation on the inner surfaces of the bearing housing and eventually forms a moisture accumulation in the bearing's sump. This moisture contamination can lead to premature bearing failure.

High-temperature steam seals are used in turbomachinery bearings to control the flow of steam to the bearing. In addition to providing pressure and temperature control, they also reduce axial sliding. A large error in the seal's perpendicularity can cause accelerated wear. For example, a 0.2-mm error can lead to two kilometers of axial sliding in a single day.

The seal is constructed of carbon ring segments. The carbon ring segments are made from special self-lubricating graphite. It is generally formed of three or more segments, bound by a garter spring. A tang is positioned between the carbon ring segments to prevent rotation.

Oil-pressure lubrication is a method for steam turbine bearings that helps them stay lubricated by applying a constant pressure to the bearings. The pressure is provided by a pump. The pump is installed on the coupling end bearing cap and shaft-driven by spur gears. The pump is equipped with equalizer pipes and standpipes to maintain the right level of oil in the bearing housings. If the sump cooling is not sufficient, an external oil cooler is installed. This system runs at a pressure of between three to five psig.

Oil-pressure lubrication is important to prevent a steam turbine from overheating. This may lead to wear on the working parts, and could affect the lubricant's properties. Therefore, proper lubrication can prolong the service life of a steam turbine significantly.