Pump Monitoring

Pumps are rotating machines for which we can implement protection, monitoring, and predictive diagnostics using vibration measurement systems.

Failure Modes

Vibration analysis provides valuable information for predictive diagnostics of pumps. The most common types of failures diagnosed in industrial pumps are:

• Imbalance
• Coupling Misalignment
• Bench failures, resonance
• Bearing Failures
• Cavitation
• Errors related to propulsion

Monitoring Systems

The recommended monitoring systems for this type of machine are:

Offline vibration

Monitoring of failure-mode parameters using periodic vibration inspection routes with portable vibration sensors.

Online Vibration and Temperature Monitoring

Here, we distinguish between pumps with shafts supported by plain bearings and pumps with roller bearings. We outline what would constitute basic monitoring, since each vibration parameter can be analyzed and broken down into several more precise monitoring parameters when advanced predictive diagnostic systems are used.

Pumps with plain bearings

Image courtesy of API670, 5th Ed.

In pumps whose shafts are supported by plain bearings, the following parameters are continuously monitored:

• Radial vibration at each bearing. Two displacement probes positioned at 90° at each bearing (microns peak-to-peak)
• Axial positioning of the shaft. Two redundant displacement sensors (microns peak-to-peak)
• Bearing temperature. Two sensors per bearing
• Temperature of the active axial bearing. Two sensors per bearing
• Temperature of the passive axial bearing. Two sensors per bearing

Pumps with bearings

Image courtesy of API670, 5th Ed.

In pumps whose shafts are supported by bearings, the following are continuously monitored:

• Radial vibration at each bearing. One accelerometer sensor per bearing or per set of bearings on the same housing (mm/s rms)
• High-frequency parameter for monitoring bearing condition, e.g., acceleration envelope, spike energy… This parameter is obtained from the same accelerometer sensor used to measure vibration.
• Temperature of each bearing housing. It is recommended to use accelerometer sensors that include temperature measurement.

Functions of Continuous Monitoring Systems (Online Condition Monitoring)

Continuous monitoring systems provide valuable functionality for the protection, supervision, and predictive diagnostics of machinery, such as:

• Integration of fault mode monitoring data into the Distributed Control System (DCS, SCADA, PI…)
• Automatic activation when vibration levels reach levels that are dangerous for the machine.
• Alerts regarding maintenance needs, e.g., balancing, relubrication, cavitation, bearing replacement…
• Automatic measurement and presentation of data in diagnostic graphs.
• Remote access to data, which facilitates diagnosis from a remote monitoring center.

Recommended Equipment and Systems for Pumps

Continuous monitoring:

• Pumps with Bearings: Vibrovision and Vibration Transmitters
• Pumps with plain bearings: SETPOINT and Dynamix 1444

Portable data loggers for vibration-based machinery monitoring: Falcon, PRE5140, PRE5050M, and Dynamix 2500

Laser Alignment: Fixturlaser Aligners

Please contact our sales department at info@preditec.com to request a proposal for monitoring your machinery.