1st Sep 2014
Amx cutaway

Amx cutaway

Pumps of any design and shape are extraordinarily technical pieces of equipment that are absolutely vital to any production line.

As we well know, pumps are vital to everyone’s day to day lives, as the average person will use 8 pumps throughout the day, lost likely without knowing so!

Therefore we have come up with our top ten ways to ruin a pump, to help engineers and operators avoid the costly mistakes that kill a pump.


  • Allowing the pump to Run-Dry

Both Mechanical Seal and Magnetic Drive Centrifugal pumps can suffer from running dry if the pump hasn’t been designed to combat it.

Allowing the pump to dry run can lead to catastrophic pump failure (depending on circumstance). For a mechanical seal pump, running dry could lead to pump cavitation and therefore seal damage. The mechanical seal could also experience thermal shock and under the right conditions could shatter within 30 seconds.

With a mag-drive pump, the bearings and shaft can rise in temperature due to the absence of liquid lubrication and subsequently melt the plastic casing.


  • Pumping solids/abrasives with the wrong pump

Pumping solids or abrasives in a pump that is not set to deal with viscosity or solids can clog and potentially break the pump. If the pump is improperly selected for the application at hand expect to see shortened life on nearly all components (casing, impeller, stuffing box, etc) impeller imbalances and seriously drops in efficiency.

It’s best to consult with the pump supplier before ordering as they would be able to tailor or make the pump fit your specifications.


  • Using the Wrong Sized Impeller

Using the wrong sized impeller for the pump causes the pump to produce too much, or too little flow, running off of its Best efficiency point. If the impeller is too big, the pump motor has to work harder to pump the fluid, eventually causing it to burn out, shortening the life of the pump. If the impeller is too small it will most likely not generate enough flow or head.


  • Incorrectly adjusting the impeller

Incorrectly adjusting the impeller can lead to increased slippage in the pump, creating more turbulence inside the pump, lowering the efficiency and increasing stuffing box pressures.


  • Operating the Pump at Shut-off

When the discharge side valve is partially or completely closed to manually control flow, it causes 100% of the input energy to be destructive. Head, high radial loads cause shaft deflection, heat and increased pressure, vibration, auto shut-off, increased energy usage and low amps.


  • Operating the pump too far back on the curve

Pumps are designed to run at the most efficient point by the manufacturer. If the pump is run, off of its efficiency point, this can quickly lead to excess recirculation, heat, radial loss, vibration, high seal temperature and vastly lower efficiency.


  • Poor pipework

Having poor piping can have a big effect of the pumps operation and its efficiency. Designs with in-verted “U”s on the suction side can trap air, while designs with a 90* immediately before the pump can cause turbulence inside the pump. Both result in suction and cavitation-al problems for the pump.


  • Improper Alignment

Up to 50% of damage to rotating machinery is directly related to misalignment. This means increased vibration, premature seal and bearing failures and increased power consumption. Excessive misalignment can even cause breakage of mounts or pump casings.

Crest Pumps deliver pumps that are mounted on a baseplate and are pre-aligned at the factory, to ensure that they pump stays properly aligned.

However, it is important to check the alignment of the pump before it is fully operational. There are type types of miss alignment, – Angular (occurs when the centrelines of the motor shaft and the pump shaft are at an angle to each other) and Parallel misalignment which occurs when the shafts are parallel, but the centrelines are displaced vertically or horizontally.


  • Mechanical Seal Installation Errors

Improperly installing the mechanical seal will cause damage to elastomers (o-rings) as well as a wide variety of other issues. Mechanical seals can be very sensitive as the faces are incredibly flat. Even a small amount of dirt or oil (such as fingerprints) can cause the faces not to align properly.


  • Using too little, too much or the incorrect lubricant

Lubrication is the number 1 cause of premature bearing failure. Using too little lubricant can cause the bearings to seize, while too much lubrication retains heat inside the bearing and also causes oil leakage.


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