Why does the centrifugal pump start and stop in the case of closing the gate valve?
The centrifugal pump starts and stops in the case of closing the pump outlet valve. Start off the pump outlet valve is to reduce the starting current, stop when the pump is closed, the outlet valve is to reduce water hammer, prevent blade from bad.
After the valve is closed to stop the cause of centrifugal pump outlet valve is closed to stop the pump to prevent the flow back into the pump, impeller, impeller in reverse, part of the mechanical seal in the pump pump impeller reversal will have adverse consequences, serious damage to the centrifugal pump, to close the valve after the shutdown.
Centrifugal pump to close the gate valve in the case of the start: the centrifugal pump power increases with its flow rate, when the flow is zero (valve closed), the minimum power to operate. Start the valve off from the angle of the motor. If the valve is started, the motor itself to start the current is larger, coupled with the power of the pump is also large, easy to cause the motor over-current trip, serious will burn the motor.