What is the primary function of check valves in centrifugal pumps?

The primary function of check valves in centrifugal pumps is to prevent backflow of water in the discharge line. When the pump is operating, it creates a flow of water from the pump into the discharge pipeline. If there were no check valve, the pressure in the system could drop when the pump is turned off or if there's a loss of prime in the suction line, causing water to flow back into the pump. This backflow can potentially lead to issues such as pump damage, cavitation, and inefficiencies in the pumping system. Check valves allow fluid to flow only in one direction, ensuring that once water is pumped out, it cannot return to the pump when it is not actively pumping. This function is vital for maintaining system efficiency and protecting the integrity of the pumping equipment.

In contrast, while other options relate to functions that may be relevant to pump operation, they do not accurately describe the role of check valves. Sediment build-up, pumping speed control, and lubrication are managed through different mechanisms and components in a pumping system.