3. Self-priming centrifugal pumpSelf-priming pump is a single-stage single-priming centrifugal pump that produces self-priming effect by the special structure of the pump itself, which is called a self-priming centrifugal pump. Compared with ordinary centrifugal pumps, there are significant differences in the structure of the pump body: first, the inlet position of the pump is improved, and sometimes the suction valve is installed; The second is to set up a gas-water separation chamber on the outlet side.The self-priming pump outside the pump is a self-priming device added to the pump, such as a vortex pump, a water ring vacuum pump, a jet pump and a hand pump.Compared with ordinary centrifugal pumps, self-priming pumps have compact structure and simple operation, which not only saves the trouble of filling a large amount of water before starting, but also eliminates the low valve of the inlet pipe, reduces the water inlet resistance, and increases the water output of the pump, but the efficiency of the ordinary centrifugal pump of the same specification is 3%~5% lower. Self-priming pumps are mostly used in light and small sprinkler irrigation units and pipeline irrigation units.Electric submersible pumpMaglev submersible pump It has achieved a major breakthrough in the field of submersible pumps in the world, and effectively solved the various drawbacks of traditional submersible pumps: such as low conversion efficiency, high power consumption, limited head, fragile bearings, frequent maintenance, etc. It is widely used in the fields of water supply and drainage, farmland irrigation and water supply in plateau and mountainous areas of industrial and mining enterprises.