Production Technology [Weekly Topic]: Startup Operation of Centrifugal Pumps (2011-02-21~02-27)

This post was last edited by shiwang528 on 2011-2-20 at 22:28. Before starting the centrifugal pump, the inlet valve should be opened while the outlet valve should be fully closed. The outlet valve is closed in order to reduce the power required to start the pump and prevent the motor from being damaged. During system startup, the pipelines are often empty, resulting in no pressure due to pipe resistance; this causes the pump to operate at a high flow rate for a short time after it starts, as there is no resistance. This often leads to vibration and noise in the pump, and even to overloading of the motor, which can result in its destruction. Closing the outlet valve is equivalent to artificially creating a pressure drop in the pipeline; once the pump starts operating normally, the valve should be opened slowly to allow the pump to work gradually and according to its performance curve. The inlet valve is opened to fill the pump and prevent air entrapment that occurs when the pump starts.

This post was last edited by shmily327 on 2011-2-21 08:53: the inlet valve is opened and the outlet valve is closed before starting the centrifugal pump； Reason for opening the inlet valve: to allow material to enter the pump, to warm the pump, for drainage, and for exhaust ； Reason for the closure of the outlet valve: During system startup, the pipelines are often empty, resulting in no pressure due to pipeline resistance. This causes the pump to operate at a high flow rate in the initial moments after it starts running at a certain speed, as there is no resistance. As a result, the pump may vibrate and make noise, and in severe cases the motor may be overloaded and damaged. Closing the outlet valve is equivalent to artificially creating a pressure drop in the pipeline; once the pump starts operating normally, the valve should be opened slowly to allow the pump to work gradually and according to its performance curve.

This post was last edited by shmily327 on 2011-2-21 08:57: Export closed, import open. Prevent excessive starting current

This post was last edited by shmily327 on 2011-2-21 08:59: Open the inlet valve to prevent the pump from running idle； Outlet valve closed: Results in a lower starting current, protecting the motor.

This post was last edited by shmily327 on 2011-2-21 at 22:35. The correct way to start a centrifugal pump is to open the inlet valve, close the outlet valve, start the pump, and once the pressure indicated by the outlet pressure gauge returns to normal, then open the outlet valve. Before starting the centrifugal pump, the outlet valve is in a closed state. When operating under no-load conditions, the current is at its minimum. Starting with the outlet valve open to fill it with liquid will cause excessive load and lead to burnout. It can also cause the centrifugal pump to draw in air, leading to air locking and damaging the pump. Since the pipelines are often empty at the time of system startup, with no pipe resistance pressure, this causes the pump to operate at a higher flow rate in the initial moments after it starts running at a certain speed, as there is no resistance. This often leads to pump vibration and noise, and even to the motor operating under overload conditions, which can result in the motor being damaged. Closing the outlet valve is equivalent to artificially creating a pressure drop in the pipeline; once the pump starts operating normally, the valve should be opened slowly to allow the pump to work gradually and according to its performance curve.

Opening the inlet valve facilitates pumping and prevents cavitation; closing the outlet valve prevents the motor from being damaged

Before starting the centrifugal pump, the inlet valve must be fully open while the outlet valve is closed. If there is no fluid in the pump chamber when starting the pump, it must be primed to prevent air locking. The outlet valve closes to prevent excessive current at the moment of startup, which could cause the motor to overheat and get damaged.

This post was last edited by shmily327 on 2011-2-21 22:37: the inlet valve is opened and the outlet valve is closed before starting the centrifugal pump； Reason for opening the inlet valve: To allow material to enter the pump chamber, as well as for heating the pump, draining waste, and releasing air. Reason for closing the outlet valve: During system startup, the pipelines are often empty, resulting in no pressure due to pipeline resistance. This causes the pump to operate at a high flow rate in the initial moments after startup, as there is no resistance; this often leads to pump vibration and noise, and even overload of the motor, which can result in its destruction. Closing the outlet valve is equivalent to artificially creating a pressure drop in the pipeline; once the pump starts operating normally, the valve should be opened slowly so that the pump can gradually operate as per its performance curve

This post was last edited by rctx97 on 2011-2-21 09:28. Reply to 1# shmily327: The inlet valve is open to allow pumping; the outlet valve is closed to prevent overload due to starting current

Before starting the centrifugal pump, open the inlet valve and close the outlet valve. Closing the outlet valve reduces the starting load, while opening the inlet valve ensures that the pump chamber is filled with liquid to prevent cavitation.