Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)

Rolling Element Bearings and Lubrications 541
Figure 20-9. Oil mist lubrication schematic (courtesy of Alemite Division of Stewart-Warner
Corporation, Chicago, Illinois).
mist then passes through a reclassifier nozzle before entering the point to
be lubricated. This reclassifier nozzle establishes the oil mist stream as
either a mist, spray, or condensate, depending on the application of the
system.
Since the mid-1950s, the oil mist lubrication concept has been accepted
as a proven and cost-effective means of providing lubrication for centrifugal
pumps. Typical petrochemical plant pump applications are illustrated
in Figures 20-10 through 20-13. Centralized oil mist systems have
also been highly successful on electric motors, gears, chains, and horizontal
shaft bearings such as on steam turbines and steel plant rolling mill
equipment.
The actual method of applying oil mist to a given piece of equipment is
governed to a large extent by the type of bearing used. For sliding bearings,
oil mist alone is not considered an effective means of lubrication
because relatively large quantities of oil are required. In this case, oil
mist is used effectively as a purge of the oil reservoir and, to a limited
extent, as fresh oil make-up to the reservoir. Purge mist lubricated pumps
generally use a constant level oiler with a balance line between the bearing
housing and the oiler lower bowl. This type of installation, which
was shown earlier in Figure 20-5, is required for bearing housings having
an excessive back pressure or vacuum and is ideally suited for purge oil