How does a self-priming fuel pump work?
Before starting the water pump, fill the pump casing with water (or there is water in the pump casing itself). After starting, the impeller rotates at high speed to cause the water in the impeller channel to flow to the volute. At this time, a vacuum is formed at the inlet, causing the water inlet check door to open. The air in the suction pipe enters the pump and reaches the outer edge through the impeller channel.
On the other hand, the water discharged by the impeller into the air-water separation chamber flows back to the outer edge of the impeller through the left and right return holes. The water flowing back from the left return hole is ejected into the impeller channel under the action of pressure difference and gravity, and is crushed by the impeller. After mixing with the air from the suction pipe, it is thrown towards the volute and flows in the direction of rotation.
Then it merges with the water flowing from the right return hole and flows along the volute. Because the liquid continuously impacts the blades in the volute and is constantly crushed by the impeller, it is strongly stirred and mixed with the air to generate a gas-water mixture, which continues to flow so that the gas and water cannot be separated. The mixture is stripped off by the partition tongue at the volute outlet and enters the separation chamber along the short tube. The air in the separation chamber is separated and discharged from the outlet pipe, while the water still flows to the outer edge of the impeller through the left and right return holes and mixes with the air in the suction pipe.
By repeating this cycle, the air in the suction pipe is gradually exhausted, allowing water to enter the pump, completing the self-priming process.
