Due to the constant impact of the liquid in the case of the blade cascade, and constantly being crushed by the impeller, with the strong mixing of the air, the formation of a mixture of water and gas, and constantly flow so that the gas can not be separated from the water. The mixture was separated at the volute tongue export stripping along the short tube into the separation chamber. In the separation of indoor air is separated from the outlet pipe to drain, while the water is still by the left and right of the backwater hole flow to the outer edge of the impeller and and the suction pipe air mixed phase. So repeated cycle, gradually will be sucked into the pipeline in the air exhaust, so that water into the pump, complete the self absorption process. Sewage pump self-priming pump diaphragm pump screw pump gear pump pump are the same, and the difference is just does not flow to the outer edge of the impeller of the backwater, and flows to the impeller inlet. Internal mixing type self priming pump in the start, must open the impeller before the bottom of the return valve, so that the pump liquid flow back to the impeller inlet. The water is mixed with the air in the suction pipe under the action of the high speed rotation of the impeller to form a gas water mixture to the separation chamber. Here the air is discharged and the water is returned from the return valve to the impeller inlet. So repeatedly, until the air exhaust, suction and water to the internal mixing of the self priming pump, working principle and external mixing.
