ordinary centrifugal pump, if the suction fluid is under the impeller, it should be irrigated in advance, which is very inconvenient. in order to pump the water in the pump, the inlet of the suction tube requires the bottom valve, and the bottom valve causes a large hydraulic loss when the pump works. alleged self-priming pump, it is before start without irrigation (the first time you start after installation to infuse water still), after a short time, by the pump itself, namely can suck up the water, into the normal work.
the self-priming pumps are divided into the following categories:
air mixture (including in-mix and exterior mix);
water wheel type;
jet flow (including liquid jet and gas jet).
gas-liquid hybrid self-priming pump working process: due to the special structure of the self-priming pump pump body, pump after stalling, there is a certain amount of water in the pump body, pump starts again due to the impeller rotation, suction pipe fully mixing of air and water, and into the gas water separation chamber, the upper part of the gas water separation chamber gas overflow, the lower the water back impeller, mixed with the surplus air inlet line again, until all the pumps and suction tube of gas discharge, complete the imbibition, and normal pumping. the water ring type self-priming pump is the combination of the water ring wheel and the pump impeller in one casing and the water ring wheel is used to discharge the gas and realize self-absorption. when the pump is working properly, the passage of the water wheel and the pump impeller is available through the valve, and the fluid in the ring is released. the jet type self-priming pump, which is composed of centrifugal pump and jet pump (or injector), depends on the injection device, which creates vacuum suction at the nozzle.
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