Ordinary centrifugal pump, if the inhalation of liquid below the impeller, the start should be pre-irrigation, very inconvenient. In order to pump the water in the reservoir, the intake of the suction pipe needs to be fitted with a bottomed valve, which causes great hydraulic losses when the pump is in operation. The so-called self-priming pump, is not required before the start of irrigation (after the first start of the installation still need irrigation), after a short period of operation, by the pump itself, that is, the water can be sucked up, put into normal work. Self-priming pump according to the principle of action is divided into the following categories: 1. Gas-liquid hybrid (including the inside and outside mixed); 2. Water ring wheel; 3. Jet (including liquid jets and gas jets). Gas-liquid hybrid self-priming pump work process: Due to the special structure of the self-priming pump body, the pump stops, the pump body has a certain amount of water, the pump starts again after the impeller due to rotation, inhalation of air and water pipe Fully mixed, and was discharged to the gas-water separation chamber, the gas above the gas-water separation chamber overflows, the lower part of the water back to the impeller, and re-inhalation of the remaining air intake pipe until the pump and the suction pipe all the gas discharge, complete since Suction, and normal pumping. Water ring wheel self-priming pump is the water ring and pump impeller combination of a shell, with the water ring to the gas discharge, to achieve self-absorption. When the pump is working properly, the valve of the water ring and the pump impeller can be cut off by the valve, and the liquid in the water ring wheel can be released. Jet-type self-priming pump, the centrifugal pump and jet pump (or injector) combination of relying on the jet device, resulting in a vacuum nozzle to achieve suction.
