Reducing cavitation risks with variable speed drives

Many fluid handling applications can be affected by cavitation, but it is a particular challenge for the water and wastewater industry where a high number of pumps are deployed. The result of cavitation is an increased risk of downtime and higher maintenance costs. The issue goes beyond the need to replace a damaged pump. In remote areas, in particular, the cost of sending a maintenance team with heavy lifting equipment to the site might be many times the cost of the pump itself. Cavitation can happen when the pumping process subjects a liquid to rapid local changes in pressure, creating vapour-filled bubbles. The exact point at which this liquid-to-vapour transition occurs depends on the pressure. At normal atmospheric pressure, water transitions into steam at 100°C. When the system pressure is reduced, this occurs at lower temperatures. Eventually, when the pressure is reduced to a vacuum, the transition happens at room temperature. Low pressure When the impeller is spinning in an...