Page 98 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

Be st Practice 2 .14
Be st Practice 2 .15 Pump Best Practices

Best Practice 2.14Practice 2.14
Best

Install mini-oil continuous flow consoles for high DN Lessons Learned
bearings (above 350,000 or when vendor 2 year field ex- Achieving optimum MTBFs with high DN pumps is not
perience is not present for the proposed oil lubrication possible unless continuous lubrication is used.
system (typically ring oil)). It has been my experience that high DN pump bearings typically are
Calculate the bearing DN as the product of the shaft speed in ‘bad actors’ (MTBF less than 12 months) if they are not equipped with
revolutions per minute and the bearing bore in millimeters. continuous oil flow consoles.
If the calculated value exceeds 350,000, obtain vendor experience
lists and contact references to ensure that the offered, non-continuous Benchmarks
flow, bearing lubrication arrangement has resulted in MTBFs greater This best practice has been since the 1980s to obtain high DN pump
than 40 months. bearing MTBFs in excess of 100 months.
If experience cannot be obtained, require continuous oil
circulation.

B.P. 2.14. Supporting Material
Please refer to B.P. 2.13 for reference material.

Best
Best
Best
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Best Practice 2.15Practice 2.15Practice 2.15Practice 2.15Practice 2.15
Remove temporary pump suction strainers after plant Lessons Learned
start-up whenever possible. If not possible, confirm proper Many pump failures have been caused by plugged, poorly
strainer design and supply with a differential pressure designed temporary suction strainers.
gauge. Many pump failures have resulted either from plugged strainers
Check all temporary pump strainers for evidence of debris after one that have not been monitored, or strainers that were made of only
month of initial pump operation. If they show no evidence of debris, mesh and sheet metal frame, that collapsed and entered the pump.
remove them! In many cases the entire pump had to be overhauled, which ex-
If strainers show evidence of debris the following action is posed the process unit to shut down during the period of spare
recommended: pump repair.
Ensure that the strainer design is rigid (perforated sheet metal with
the appropriate mesh size over the perforated plate facing the Benchmarks
direction of flow) This best practice has been used since the mid-1980s, resulting in
Install a differential pressure gauge or differential pressure pump applications with optimum safety and MTBF in excess of 80
transmitter around the strainers and have the differential checked months.
by operators on their daily rounds.

B.P. 2.15. Supporting Material Also consult plant operators, if the pump application in
question is presently operated in your plants, to ensure that the
When reviewing the P&IDs for all pump applications, pay at- strainer can be removed.
tention to the symbol TS and remember that the T stands for If the strainer cannot be removed, it must be of permanent
temporary. design (perforated plate with appropriate mesh size if required
It is recommended that each pump application be reviewed attached to the plate facing the direction of flow) and supplied
with the process licensor’s engineers to ensure that the strainer with a differential pressure gauge or transmitter for daily
can be removed without reducing the pump MTBF. monitoring.

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