Prevent Pump Damage through Automatic Detection of Cavitation

Written by Todd Reeves, Emerson Process Management

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Automated Monitoring

In fact, automated monitoring of pumps already exists. Software embedded in a machinery health monitoring device collects vibration data continuously and analyzes the data results automatically. The use of embedded analysis logic of the type portrayed in Figure 2 enables the monitoring system to do more than just present high vibration readings, which do not really tell an operator what he or she needs to know to alter the process.

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Figure 2

However, a smart machinery health device can deliver a message indicating that a pump is experiencing cavitation right now (see Figure 3), which really empowers that operator to correct the problem immediately.

Figure 3

Additional details can also be provided about what to do while the condition is occurring in order to alter the circumstances that cause the pump to cavitate. By following these suggestions, an operator can extend the life of the pump and minimize repair costs.

This is a real-life solution that enables operators to make positive changes in the process condition to eliminate the cavitation. It may involve opening a valve, which affects the NPSH, or adjusting the process fluid's temperature, which affects the vapor pressure. In certain cases, process design changes may even need to be addressed to eliminate the recurrence of cavitation.

A smart machinery health device can continually measure the operating parameters of key motor-pump machine trains in the field and report a consolidated analysis based on current operating conditions. This technology is capable of making in-the-field assessments and automatically warning plant personnel whenever the possibility of cavitation exists.

Automated diagnostics packages can augment the work of maintenance personnel by giving the analysis directly to operators in time for them to make appropriate adjustments. When combined with information from other sources, such as lubricant analysis and infrared imaging, a true picture emerges of the operating condition of an asset and its potential for failure.

Todd Reeves is the process industries marketing manager for machinery health management at Emerson Process Management, 835 Innovation Drive, Knoxville, TN 37932, 865-675-2400 ext. 2101, Fax: 865-218-1401, http://www.emersonprocess.com/.

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