Pumps

Best Practices for ANSI Pumps

Selection

• Operate pumps at 85% to 110% of best efficiency point (BEP).
• Ensure NPSHA is 20% or 1.5m (5ft) over NPSHR, whichever is greater.
• Impeller trims of 75% are optimal, so trim impellers 60% to 95% of maximum.
• Consider using variable speed technology for multiple operating point conditions.

Installation

• Level pump, base & motor, and ensure the area is free of soft foot conditions.
• Provide at least 10 diameters of straight pipe to the pump’s suction inlet.
• Use highly rigid baseplates, such as reinforced stilt or grout installed designs.
• Utilize low shrink grout to install baseplates. Epoxy grout is superior.
• Design piping to ensure minimum stress, i.e., fasteners should be installed without force.

Alignment

• Use laser or reverse dial indicator technology to align pump & motor.
• Align before and after the pump & piping are bolted together.
• Consider using C-flange motor adapters when pumping fluids hotter than 95°C (200°F).
• For pumping temperatures greater than 175°C (350°F) consider centerline mounted casing.

Operation

• Refer to equipment operation & maintenance manuals for start-up procedures and checklists.
• Slowly close process valves to avoid water hammer.
• Consider soft start for frequent on-off duty pumps.
• Avoid run-dry conditions.
• Operate spare pumps at least every three months to maintain proper working conditions.

Preventive Maintenance

• Change lubrication at recommended intervals.
• Protect lubricant from contamination.
• Maintain mechanical seal flush environment.
• Predictive maintenance, vibration monitoring and lubricant analysis are beneficial practices.