Cavitation in a fluid is a phenomenon that occurs when air bubbles in a solution suddenly collapse. This happens because the pressure inside the pump changes, which then creates shock waves. These shock waves cause the components of the solution to get eroded. When the net positive suction head is lower than the net positive suction head required, then cavitation will start to occur. In most cases, the force generated by the shock waves is strong enough to damage the components of a pump, such as its seals and impeller. In some cases, a flooded inlet is not enough to prevent a pump from experiencing a condition known as cavitation. The lowest pressure that a given pump can experience is located at its suction side. For instance, a positive displacement pump’s lowest pressure is near its rotor meshing. On the other hand, a centrifugal pump’s lowest pressure is near its eye. Although it can be caused by different pump types, such as positive displacement and centrifugal pumps, it is usually triggered by the presence of too low pressure near the eye. This condition then causes bubbles to form and eventually collapse. When the pressure inside the solution increases due to the rotation of the pump’s impeller, the bubbles will also start to disappear. When the vapor pressure of a given fluid is predictable, the bubbles in the solution will form as the pressure inside the pump drops below its vapor pressure. When the pressure inside the pump exceeds the vapor pressure, the bubbles will collapse. This form of collapse is usually violent and rapid. Aside from the environment, a poorly executed processing line can also cause a pump to experience a condition known as pump cavitation.
Typical indications of cavitation:
Higher than usual power consumption
HOW TO PREVENT PUMP CAVITATION
To prevent a pump from experiencing a condition known as pump cavitation, it’s important to identify the cause of the pressure drop and determine the location of the problem. Doing so will help prevent additional pressure drops from forming. In some cases, a blockage can also be caused by debris that’s collected near the pump’s suction lines. To prevent this issue from happening again, it’s important to clear the debris from the lines. However, it’s important to avoid throwing the pieces back toward the source of the problem. Before buying a new pump, it’s also important to follow the manufacturer’s performance guidelines to ensure that the device’s design specifications are met. Having a rough estimate of the net positive suction head required by the pump will help determine its optimal operation.