What is the function of check valves in reciprocating pumps?

The primary function of check valves in reciprocating pumps is to prevent backflow. In the context of a reciprocating pump, a check valve is crucial for ensuring that the fluid being pumped moves in one direction only. When the pump operates, the check valve opens to allow the liquid to flow into the discharge line. As the pump's piston moves backward or stops, the check valve closes, preventing the liquid from flowing back into the pump itself.

The design of a check valve allows it to respond to changes in pressure, ensuring that when the pressure on the discharge side of the pump exceeds the pressure on the inlet side, the valve remains closed despite any reverse flow attempt. This functionality is vital for maintaining the efficiency of the pumping system and preventing issues such as loss of prime, contamination, and damage to the pump mechanisms that could occur due to backflow.

The other options present functions that do not accurately describe the role of check valves. For example, increasing pressure pertains to the pump's operation rather than the check valve's function, and measuring liquid levels is not a feature of check valves. Allowing flow in and out incorrectly implies a lack of directionality, which contradicts the purpose of preventing backflow. Hence, understanding the role of