Xylem 8100 Series Centrifugal Pumps AC2515 REV.C - Manual (Page 24)

assured if the level of grease is maintained at
about the capacity of the bearing and 1/3 to
1/2 of the cavity between the bearing and
grease fitting. Any greater amount will, as a
rule, be discharged by the seal or vent and be
wasted.
The importance of proper lubrication cannot
be over emphasized. Lubrication frequency
depends upon the speed, size and type of
bearing, and operating temperature or
environmental conditions. Generally, the
smaller the bearing and faster the speed, the
more frequent the interval for relubrication
with grease. It is recommended that a certain
amount of grease be added at intervals of
three to six months to replace the small
quantity of grease lost between grease
flushing intervals. For average bearing
housing designs, one (1) ounce of grease will
be sufficient at these intervals. For larger or
smaller bearing housings this amount may
have to be adjusted.
Unfortunately, there is not a grease available
which will not harden over time and become
less suitable for its purpose due to oxidation.
It is good practice to remove all the old
grease about once a year and thoroughly
clean the bearings. This should be done
during major overhauls. After gaining
experience with each individual pump and its
operating characteristics, the relubrication
and flushing intervals may be adjusted
accordingly. Keep good records and add
grease at regular intervals. Then adjustments
can be made after the first overhaul, if
necessary.
Periodic Addition of Grease
Grease lubricated ball bearings are packed
with grease at the factory. Store the pump in
a clean, dry place prior to its first operation.
If one is uncertain about the amount of
grease in a bearing at relubrication intervals,
the safe rule is to add grease while the pump
is stopped to avoid overloading. Remember,
a ball or roller bearing in most applications is
assured of adequate lubrication if the level of
grease is maintained at about the capacity of
the bearing and 1/3 and 1/2 of the cavity
between the bearing and grease fitting. Any
greater amount will, as a rule, be discharged
by the seals or vent and be wasted. Excess
grease is the most common cause of
overheating of the bearings. Remove vent
plugs for the first 24 hours of operation after
regreasing.
Bearing Temperature
Normally the maximum desirable operating
temperature for ball bearings is 180°F.
Special designs may have higher limits.
Should the temperature of the bearing frame
rise above the limit, the pump should be shut
down to determine the cause. Check with an
accurate temperature measuring device to be
sure.
Oil Lubrication of Bearings
Oil lubrication on 8100 Series pumps is
considered special. Oil lubricated pumps are
installed with Trico oilers (See Figure 15).
The oilers keep the oil level in the housings
constant.
After the pump has been installed, flush the
housing to remove dirt, grit, and other
impurities that may have entered the bearing
housing during shipment or installation. Then
refill the housing with proper lubricant. (The
housing must be filled using the Trico oiler.)
The oil level will be maintained by the Trico
oiler. (See the SERVICE section for proper
instructions.)
FIGURE 15 – TRICO OILER
A Mobil Oil, DTE Medium, or equal, meeting
the following specification will provide
satisfactory lubrication. Similar oils can be
furnished by all major oil companies. It is the
responsibility of the oil vendor to supply a
suitable lubricant.
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