Why do solar water pumps need self-priming devices?

The reason why the self-priming device is needed is matched according to the working principle of the solar water pump. If the configuration of the solar water pump can pass through, then the self-priming device is not needed in the ordinary use process. So under what circumstances does a solar water pump need a self-priming device?

When the impeller rotates, only the "textured" things can be thrown from the center to the surroundings, so that a clear vacuum is formed in the center. Obviously, if the pump cavity of the solar water pump is filled with air, no matter how fast the rotation is, a vacuum cannot be formed. Therefore, before the solar water pump works, the pump cavity must be filled with liquid in advance. This is the origin of the self-priming device.

What are the types of self-priming devices?

One is to use compressed air to pump the pump casing to vacuum water; before starting the solar water pump, during the operation of the self-priming device, the valve on the outlet side should be kept closed, or a spring-loaded back pressure valve should be installed when the outlet pressure reaches the normal working pressure of 60 % Is automatically opened, vacuum suction must be connected to the high point on the suction side of the pump, and placed in the suction tube to form an air cavity. Usually a compressed air with reduced pressure is used, and the venturi effect is used to create a vacuum in the pump casing and fill it with water. This device allows the centrifugal pump to dry for a short time.

Another kind of self-priming device is its own vacuum pump. Some pumps are self-priming devices, such as fire emergency water pumps. This kind of disadvantage is that the pump structure is complicated and the volume is increased, and the water tank above must be ensured every time it is started. Full of water.