Can Automated Detection Help Prevent Cavitation?
If you’ve read our earlier post on cavitation, you’ll know that pump cavitation can cause significant damage – premature valve failure, decreased flow pressure and repetitive stress on other critical parts such as the impeller and internal components that will eventually failure of your pump over time.
Even though pump cavitation can be easily detected by an unmistakable popping or what sounds like rocks rolling through the pump, someone has to be near enough to hear. This means that cavitation can go on for weeks.
The longer cavitation occurs undetected, the greater the damage, and the greater the cost of repair. Automated detection can help prevent cavitation by monitoring vibration levels – allowing early correction by merely adjusting flow or tank level, or by changing piping or pump design.
What is the role of vibration?
When vapour bubbles collapse, they typically make that recognizably loud, popping sound. However, they also create vibration patterns that can be analysed. If high frequency energy is increasing (higher vibration), it’s a sign that cavitation is getting worse, leading to damage of the impeller and seals, as well as increasing wear on the pump bearings.
**Note: If vibration is present on both bearings it’s generally as a result of pump cavitation, whereas if vibration has increased on just one bearing, it’s usually a bearing or lubrication issue.
However, cavitation is often intermittent as it can depend on the process. Many things can contribute to pump cavitation, including flow rates, tank levels, valve positions, piping and pump design to name a few. This means that it can be difficult to detect cavitation when it happens. Operators can only do something when they hear the sound of cavitation, usually when walking by the pump. Vibration readings can also be confusing if data is collected on a set schedule (such as once a month) because changing process conditions mean that cavitation can occur for several days a week.
Is automated monitoring a solution?
A device that can collect and analyze vibration data continuously offers a viable solution. Often called a smart machinery health device, this automated monitoring system can scan for changes in the pump’s vibration, analyze results automatically, and warn maintenance personnel to correct any issues while the condition is occurring. This allows operators to make changes in the process condition during operation to eliminate cavitation, such as opening a valve or adjusting process fluid temperature. Occasionally, process design may have to change, although this will require downtime.
Ultimately, automated diagnostics can help operators extend the life of a pump and minimize repair costs by giving them time to make adjustments. When combined with other high-tech information, such as lubricant analysis and infrared imaging, automated monitoring provides a holistic picture of the pump’s operating condition and its potential for failure.
If you want to find out more about automated diagnostics and its advantages, call our toll-free number 1-800- 367-4180. We have experts on hand to help you choose, install, and maintain a variety of equipment.