What is the working principle of the self-priming pump?

What is the working principle of the self-priming pump?

Ordinary centrifugal pumps, if the suction liquid surface under the impeller, should be pre-irrigation when starting, it is inconvenient. In order to store water in the pump, a suction valve inlet is required to install a bottom valve, and the bottom valve causes a large hydraulic loss when the pump is operated. The so-called self-priming pump, is not required before the start of irrigation (the first start after installation still need to water), after a short period of operation, relying on the role of the pump itself, that can suck up the water, into normal work. Self-priming pump is divided into the following categories according to the principle of action:

1. Gas-liquid hybrid (including internal mixing and external mixing)

2, water wheel 3, jet type (including liquid jets and gas jets). The working process of the gas-liquid hybrid self-priming pump: due to the special structure of the self-priming pump body, after the pump stops, a certain amount of water is stored in the pump body. After the pump is started again, the air and water in the suction pipeline are sucked due to the rotation of the impeller. Fully mixed and discharged to the air-water separation chamber. The gas in the upper part of the air-water separation chamber overflows. The lower part of the water returns to the impeller and mixes with the remaining air in the suction pipeline until the gas in the pump and the suction tube is completely discharged. Suction, and normal pumping. The water ring wheel type self-priming pump is a channel for the water ring wheel and the pump impeller, and drains the liquid in the water ring wheel. Jet self-priming pump, which is a combination of a centrifugal pump and a jet pump (or ejector), relying on a spraying device to create a vacuum at the nozzle to achieve suction.