If your pump system performance isn’t what it should be, it might make sense to look at the installation in three different areas:
- The suction side;
- The pump in the middle;
- The discharge side.
This “segmenting” of the pump system might help with your troubleshooting process. Of course, one likes to think that the system was designed and constructed correctly in the first place. And then you hope that start-up and operation went according to instructions in the manual or from the supplier.
If everything went well in start-up but there is indeed some performance problem you are dealing with, 9 times out of 10 the issue is going to be on the suction side.
Performance issues are often caused by insufficient suction energy, inadequate net positive suction head available (that’s where NPSH comes into play), air entrainment or increases in the running clearances above design.
If you don’t understand the pump curve, get a pump expert in there to help. The pump will operate on or near its performance curve at the point where the system curve intersects the pump curve.
A situation we see quite a bit is when a system was originally designed for one application but is now struggling to perform on a different application.
A pump must be operating as near to the best efficiency point as the system and process design will allow. As operations depart from this best efficiency point, the pump will develop high radial thrust that greatly affects mechanical seal and bearing life.
Are you sure your pump system is operating at the best efficiency point? What are you seeing in your plant? Can we help?