What is the impact of the opening degree of the centrifugal pump outlet control valve?
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The outlet flow rate of a centrifugal pump is controlled by adjusting the outlet valve; so what impact does opening this valve wider have on production? What’s the harm in turning it off? Generally, centrifugal pump outlets are equipped with manual valves as well as a set of control valves. When should we adjust the manual valves and when should we adjust the control valves?
After the centrifugal pump is started, the manual valve must be opened fully, and then the pump’s outlet pressure and flow rate are controlled via the control valve. When the control valve is closed, the pump outlet pressure increases and the flow rate decreases; the opposite occurs when the valve is opened. When the control valve is fully closed, the pump pressure rises to its maximum value while the outlet flow rate becomes 0.
Why shut it down completely during normal production? At startup, the outlet valve remains closed for no more than 3 minutes. The opening and closing of the valve are adjusted according to the required flow rate.
Closing the outlet valve partially or completely at startup is done to reduce the starting current of the centrifugal pump; this starting current is 3-8 times higher than the normal operating current. By closing the outlet valve partially or completely, the flow rate of the centrifugal pump is minimized, and its power consumption is reduced as well. The centrifugal pump should not be started repeatedly, in order to avoid damaging it. There are many reasons why a centrifugal pump may not deliver the desired flow rate, such as vacuum conditions, cavitation, etc., all of which can lead to a decrease in the pressure at the pump’s outlet. Closing the outlet valve helps to prevent the liquid level in the upstream equipment from dropping too low; it is one method used to address the issue of insufficient flow rate from the pump. This is just my personal opinion, for reference only
The manual valve at the centrifugal pump’s outlet should have its opening adjusted properly when starting the pump; under normal operation, the control valve should be used for adjustment first, and the manual valve should only be adjusted if there is a problem with the control valve or if its setting is outside the acceptable range.
When a centrifugal pump is started, there is no water in the pump’s outlet pipeline; as a result, there is no pipeline resistance or head loss. After the pump starts, its head is very low while the flow rate is high. At this point, the motor driving the pump generates a large amount of power, which can easily lead to overload and damage to the pump’s motor and electrical wiring. Therefore, it is necessary to close the outlet valve at the time of startup in order for the pump to operate properly.
When a centrifugal pump is started, there is no water in the pump’s outlet pipeline; as a result, there is no pipeline resistance or head loss. After the pump starts, its head is very low while the flow rate is high. At this point, the motor driving the pump generates a large amount of power, which can easily lead to overload and damage to the pump’s motor and electrical wiring. Therefore, it is necessary to close the outlet valve at the time of startup in order for the pump to operate properly.
1# lj20052004: The centrifugal pump was selected during installation, and the valves serve a minor regulatory function. The valve should not be closed for more than 3 minutes, as pressure buildup can damage the pump.
The flow rate of the pump is primarily regulated by valves, which are adjusted according to the process requirements to ensure what is necessary for the process. Under normal circumstances, after adjusting the volume to a certain range, it can be adjusted using a control valve.