Generator Maintenance Oil Flushes 
When performing a major inspection on your turbine generator, it is important that you do a thorough and proper oil flush. Oil system cleanliness is vital to the reliable operation of your unit. Doing an improper oil flush can create more problems if your procedure is not comprehensive. There are two main types of oil flushes:

·         Maintenance oil flush

·         High velocity oil flush

A maintenance oil flush should always be performed after any minor inspection which includes the bearings. The oil reservoir pumps are utilized and each bearing is bypassed. The oil is sampled as it returns to the reservoir until no hard particles greater than 5 microns are detected. The system is generally flushed for a minimum of 12 hours.

After a major inspection, a high velocity oil flush should be performed. High oil velocities can be developed by bringing in a separate oil pump skid or by using the existing oil pumps if they are of sufficient capacity. It is important that all system restrictions (orifices, coolers) be removed from the system so that sufficient flows can be obtained. Heating the oil is also necessary to achieve optimal cleaning results. In especially dirty systems, hydroblasting oil lines is an effective way of pre-cleaning prior to the high velocity flush. Oil coolers should always be removed and cleaned as they are natural dirt traps.
In any case, it is important to design the cleaning process that fits your particular unit and outage.