Page 425 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Steam Turbines and Turboexpanders 403

equipped with a Class 1 or Class 2 rotor (rotor class designated on Table
8-9), are furnished with oil rings. The oil rings provide bearing lubrica-
tion during turbine startup and shutdown. This arrangement employs a
standpipe, installed in the bearing housing oil drain connection, to main-
tain the proper oil level for oil ring operation.
Turbines equipped with a Class 3 rotor are pressure lubricated and use
an auxiliary oil pump for bearing lubrication during turbine startup and
shutdown. Standpipes and cooling tubes are also used with this arrange-
ment but oil rings are not.

Fgura 8-13. Backseating the trip valve.