Centrifugal Pump Performance Monitoring

If the inlet flow of a pump is restricted by a clogged strainer, closed valve or other obstruction, gas filled cavities or bubbles can form in the process media due to negative pressure. These sound like the pump is moving rocks and can cause excessive wear on the case and impeller, and increase vibration for the entire installation if not corrected. Emerson’s pressure transmitters can detect this condition, and vibration sensors warn of changes to the installation so the problem can be corrected.

Vibration in rotating equipment is the greatest enemy of component life. The most common source of vibration for direct-coupled pump installations is shaft misalignment. If the equipment base is not fully solid and if the installation has not been adjusted to bring the two shafts onto a coaxial line when the equipment is at running temperature, excess vibration results. Cavitation can also enter into the picture, but it is more easily recognized. Emerson’s vibration sensors, combined with Plantweb Insight software, determine when changes in vibration characteristics indicate formation of damaging conditions.

The mechanism to keep fluid inside the pump and avoid leakage where the shaft enters the case is a critical vulnerability. Old pump designs used packing, but mechanical seals have gained popularity. The seal has its own liquid system to equalize pressure, and the flushing mechanism cleans debris from the sealing surfaces. This system must be monitored for pressure and fluid level to ensure correct operation, and Emerson offers instruments well-suited to this application.

Common problems and failures associated with pumps include cavitation, mechanical seal failure, bearing failure, impeller wear or damage, leakage, overheating, impeller or shaft misalignment, insufficient flow or low pressure, motor or drive issues, material compatibility issues, and foreign object damage. Proper pump health monitoring and proactively addressing issues promptly are essential to mitigate these problems and ensure optimal pump performance.