Centrifugal pumps are commonly used in various industrial applications, including water treatment, chemical processing, and oil refining. Before starting a centrifugal pump, it is essential to close the outlet valve as a crucial precautionary measure. This article will explore the reasons behind closing the outlet valve before starting the centrifugal pump, emphasizing equipment protection and ensuring safe and efficient operation.

1.Preparations Before Starting the Centrifugal Pump

Before starting a centrifugal pump, several preparations must be carried out to ensure safe operation. These preparations include inspecting the pump's condition, connecting the power source properly, confirming that the inlet and outlet pipelines are free from any blockages, and aligning the pump shaft with the motor shaft. Among these steps, closing the outlet valve is one of the critical preparatory measures.

2.Purpose and Significance of Closing the Outlet Valve

The purpose of closing the outlet valve is to prevent the liquid from flowing out of the pump's outlet. The following are the key significance of this action:

Preventing Dry Run: When starting the centrifugal pump with the outlet valve open, the liquid will immediately flow out, resulting in dry run conditions. Dry run can cause damage to the pump's impeller and seals, and in severe cases, it may even lead to motor damage.

Avoiding Water Hammer: Water hammer is a phenomenon caused by sudden stops or rapid changes in liquid flow velocity. Starting the centrifugal pump with the outlet valve suddenly closed can create water hammer, exerting pressure shocks on the pump equipment and pipelines, potentially causing damage.

Reducing Starting Load: Closing the outlet valve before starting the centrifugal pump can reduce the starting load on the pump, which is beneficial for protecting the motor and reducing energy consumption.

3.Steps to Close the Outlet Valve

Closing the outlet valve is a critical operation that must be performed following the correct procedure. The following steps outline the process:

Check the Status of Inlet and Outlet Valves: Before closing the outlet valve, ensure that both the inlet and outlet valves of the pump are in the closed position.

Close the Outlet Valve: Gently rotate the outlet valve handle or actuator to close the valve. Avoid applying excessive force to prevent damage to the valve.

Confirm the Operation: Verify that the outlet valve is closed and check other pump-related equipment to ensure that everything is ready for operation

4.Starting the Centrifugal Pump

After closing the outlet valve, the centrifugal pump can be started. During the startup process, closely monitor the pump's operation to ensure smooth and stable performance. If any abnormalities are detected, promptly stop the pump's operation, inspect and address the issues before attempting to start again.

Closing the outlet valve before starting the centrifugal pump is a crucial step to protect equipment and ensure safe operation. It effectively prevents dry run and water hammer, reducing potential risks and hazards to the pump and surrounding equipment. By strictly adhering to the operational procedure and maintaining proper maintenance practices, centrifugal pumps can operate safely and efficiently, providing reliable pumping services across various industries.