Page 357 - Centrifugal Pumps 2E

322 Centrifugal Pumps: Design and Application

BEARING APPLICATION CHART - PRODUCT LUBE
Rush Pressure (1)
Particle Six* (2) > 10 PSIG >16PSIG > 25 PSIG
-CIO Micron (Clean) Carbon Teflon Teflon
>• 1 0 Micron Carbon Carbon Teflon
<: 400 Mesh (Fine)
>• 400 Mesh Note 3 Carbon (4| Teflon (4)
< 20 Mesh (Coarse)
1. Discharge pressure at mounting plate. Min flow of % GPM per bearing is re-
quired. % GPM is recommended,
2. Particle sizes are as follows:
10 micron - .0004 in.
400 mesh (fine) - .0015 in.
20 mesh (coarse) * .0328 in.
3, Exttrnat flush only at 25 PSIG (Teflon bearings)
4, Cyclone separators required. Refer to chart below.

Figure 15-20. Bearing and lubrication for nonmetallic vertical sump pumps.

A lip seal or closure is installed in the mounting plate where the shaft
passes through preventing gases and vapors from escaping out of the
sump. If the sump is under pressure or has toxic fluid, a mechanical seal
is employed. Likewise, a gasket is placed between the mounting plate
and pit cover. A strainer is placed at the bottom of the casing. It is made
out of a polypropylene material, the net area of which should be three
times the entrance area of the suction nozzle.