The principle of self-priming pump

The core principle of a self-priming pump is to achieve automatic exhaust and water absorption through a circulation process of pre stored liquid and gas mixing and separation. Its working process is as follows:

1. Necessary conditions before startup

Sufficient liquid (drainage) must be pre stored in the pump chamber, otherwise self-priming circulation cannot be established.

2. Step by step analysis of self-priming process

Gas liquid mixing stage:

The impeller rotates at high speed, strongly stirring the air in the suction pipe and the liquid stored in the pump in the impeller channel to form a foam like gas-liquid mixture.

The mixture is thrown towards the outer edge of the snail shell under the action of centrifugal force.

Gas liquid separation stage:

After the mixture enters the gas-liquid separation chamber, the gas accumulates towards the top due to its low density and is discharged outside the pump through the exhaust pipe.

The liquid sinks due to high density and returns to the inlet of the impeller (internal mixing type) or the outer edge of the impeller (external mixing type) through the reflux hole.

Cycle exhaust of gas:

The returned liquid is mixed again and the above process is repeated until the air in the suction pipeline is completely discharged.

The pipeline forms negative pressure, and external liquid is continuously sucked in under atmospheric pressure.

3. Performance influencing factors

Sealing clearance: The clearance between the impeller and the pump casing should be maintained at 0.25~1.10mm, as excessive clearance can reduce efficiency;

Rotational speed: The higher the rotational speed, the faster the exhaust speed, but excessive speed can lead to insufficient gas-liquid mixing;

Liquid storage capacity: Insufficient liquid level will result in self-priming failure.