Which of the following statements about foot valves is correct?

Foot valves are designed specifically to prevent backflow in a piping system. Their primary function is to maintain the flow of liquid in one direction, particularly in submerged applications like those found at the bottom of a suction line for pumps. When the pump is operational, the foot valve remains open, allowing fluid to flow into the pump. However, when the pump stops, the foot valve closes automatically due to the weight of the liquid above it, preventing any backflow or siphoning effect that could potentially empty the suction line, which would hinder the pump's ability to prime and operate efficiently.

Regarding regulation of pressure, controlling flow rate, and installation orientation, other components are typically responsible for those functions. Foot valves do not inherently regulate pressure; they merely prevent backflow and ensure a consistent supply of liquid to the pump. Flow rate control is generally managed by other types of valves or flow meters that are designed specifically for that purpose. Foot valves are predominantly installed in a vertical position to effectively utilize the pressure of the liquid column above them, although installations can vary based on specific designs and applications.