Page 179 - Know and Understand Centrifugal Pumps

Know and Understand Centrifugal Pumps

normally softer than the shaft material, and abrasives can be
absorbed into or imbedded into the bearing material without
destroying it. This is certainly not the case with precision ball and
roller bearings.
Bearings should not be left exposed overnight. Coat bearings
with clean oil and cover them with clean oil or wax paper.
Clean the internal bearing housing and shaft seat before
installing the bearing.
rn Clean and paint all un-machined internal surfaces inside the
bearing housing with oil resistant paint.
w Do not spin a new bearing by hand or with compressed air. This
introduces dirt and grit and causes it to imbed into the
protective grease.
4. Inadequate Lubrication
Inadequate means not enough lubricant, and it means the wrong
type of lubricant. If the lubrication is insufficient, the bearing suffers
short life from too much friction, high heat, and metal-to-metal
contact between rolling and stationary elements. For horizontal
shafts, the proper oil level is: half way up the lowest ball or roller in
the bearing assembly. Some pumps have a site level indicator
showing the oil level inside the bearing chamber. It is recommended
that you install these indicators if your pumps don’t have them.
Teach the operators and mechanics to pay attention to the
indicators. As for greases, lithium based grease is for pumps.
Polyurea based grease is for electric motors. If these two greases are
mixed or confused, it will lead to premature pump bearing failure.
5. Excessive Lubrication
Too much lubrication is as damaging to bearings as insufficient
lubrication. It also leads to overheating. When the oil level is too
high, the bearing balls and rollers crash into the oil pulling in air
and bubbles leading to foaming. The foam and froth mixed with air
cannot remove the heat.

In cold clii nates, many homes and businesses use double and tric )le pane windows.
The air poi cket between double and triple pane windows serves tl o insulate so that
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heat is not lost througn tne wind ows. LiKewise, air bubbles in oil prevent the heat
from escaping.