The centrifugal pump is a vane pump. During the rotation process, the rotating impeller rotates the mechanical energy to the liquid due to the interaction of the vane and the liquid, so that the pressure of the liquid can be increased to achieve the purpose of transporting the liquid.
1. The lift generated by the centrifugal pump at a certain speed has a limit value. The operating point flow and shaft power depend on the condition of the system of the unit connected to the pump (pore difference, pressure differential and piping loss). The head changes with the flow.
2 The work is stable, the conveying is continuous, and the flow and pressure are not pulsating.
3 Generally, there is no self-priming ability. It is necessary to fill the pump with liquid or vacuum the pipeline before starting work.
4. The vertical pipeline centrifugal pump is started when the discharge line valve is closed, and the vortex pump and the axial flow pump are started in the fully open state of the valve to reduce the starting power.
Because the centrifugal pump lifts the water by the suction force that forms the vacuum by the centrifugal force of the impeller, when the centrifugal pump starts, the gate valve must be closed and watered. The water level is above the impeller and the air in the centrifugal pump is discharged before it can be started. After starting, a vacuum is formed around the impeller to suck up the water, and the gate valve can be automatically opened to lift the water. Therefore, the valve must be closed first.
In order to ensure the safe operation of the centrifugal pump, the centrifugal pump unit should be thoroughly and thoroughly inspected before starting, especially for the newly installed or overhauled pump. After the inspection, we must also pay attention to the parking operation to extend the life of the vehicle and ensure that the centrifugal pump can work normally.
The centrifugal pump parking operation is as follows:
(1) Close the vacuum gauge and pressure gauge valve;
(2) Slowly close the exit gate valve and stop the motor.
Centrifugal pump parking precautions:
(1) If the centrifugal pump stops the motor first and then closes the outlet valve, the high pressure liquid in the extrusion pipe may be reversed into the pump, causing the impeller to reverse at a high speed, resulting in damage.
(2) If the pump is not used for a long time or the ambient temperature is lower than 0 °C, the water in the pump should be released.
(3) For the axial flow pump, there is no gate valve on the pressure pipe, and it can be stopped directly.
(4) For deep well pumps, the pump cannot be restarted immediately after stopping to prevent water flow from impacting. It usually takes 5 minutes to start again.