What is the purpose of the foot valve in a centrifugal pump installation?

The purpose of the foot valve in a centrifugal pump installation is to retain liquid in the line. This valve is typically installed at the bottom of a suction pipe, submerged in the fluid being pumped. Its main function is to maintain the prime of the pump by preventing the liquid from draining back into the source when the pump is turned off. This ensures that when the pump is restarted, it has immediate access to the liquid, facilitating smooth operation and preventing damage that could result from running the pump dry.

While foot valves may help in preventing backflow as a secondary benefit, the essential function that defines its role in centrifugal pump systems is retaining liquid in the line, allowing for consistent and reliable pump operation.