Should the outlet valve be closed when the fluorine-lined centrifugal pump starts?

When starting the fluorine-lined centrifugal pump, a lot of things should be paid attention to. Should the outlet valve be closed when the fluorine-lined centrifugal pump starts?

When the fluorine-lined centrifugal pump starts, there is no water in the outlet pipe of the pump, so there is no pipe resistance and lifting height resistance. After the start-up of fluorine-lined centrifugal pump, the head of fluorine-lined centrifugal pump is very low and the flow rate is very large. At this time, the output (shaft power) of the pump motor is very large (according to the performance curve of the pump), which is easy to overload and damage the pump motor and circuit. Therefore, the outlet valve should be closed at start-up to make the pump run normally.

No matter which kind of pump, its blades must be immersed in water in order to start to establish the head. Both fluorine-lined centrifugal pump and mixed-flow pump have suction heads, so the suction pipe must be filled with water before starting. At this point, an intake valve needs to be set at the inlet to keep water in the pipe. The axial flow pump has no suction head, and its blades must be immersed in water at any time. So there is no intake valve problem.

Two points must be met before starting the fluorine-lined centrifugal pump.

1. Fill the pump housing with water to form a vacuum.

2. The gate valve on the outlet pipe must be closed so that the pump does not form a flow, which can reduce the starting current of the motor and facilitate the smooth start of the pump. With the smooth start of the pump, the gate valve should be opened slowly in time.

The fluorine-lined centrifugal pump elevates the water through the vacuum suction formed by the centrifugal force of the impeller. Therefore, when the fluorine-lined centrifugal pump starts, the outlet valve must be closed and water must be injected. When the water level exceeds the position of the impeller, the fluorine-lined centrifugal pump can only be started after exhaust. After starting, a vacuum is formed around the impeller, which absorbs water upward and can automatically open the water lift. Therefore, the outlet valve must be closed first.