What Is The Working Principle Of Self-priming Seawater Pump

Sep 20, 2025

A self-priming seawater pump is a hydraulic machinery used for pumping water, consisting of a pump body, a rotating assembly, a faucet assembly, a discharge cover, as well as an inlet pipe, an outlet pipe, and a blocking net. What is his specific working principle?

The self-priming seawater pump adopts an axial return liquid pump body structure.

The pump body is composed of a suction chamber, a liquid storage chamber, a scroll chamber, a liquid return hole, a gas-liquid separation chamber, etc. After the pump starts normally, the impeller sucks the liquid in the suction chamber and the air in the suction pipeline together, and is fully mixed in the impeller.

Under the effect of centrifugal force, the liquid carries gas to the outer edge of the scroll chamber, forming a white foam belt with a certain thickness and a high-speed rotating liquid ring on the outer edge of the impeller.

The gas-liquid mixture enters the gas-liquid separation chamber through a diffusion tube. At this point, due to the sudden decrease in flow rate, lighter gases are separated from the mixed gas-liquid mixture, and the gases continue to rise and be discharged through the pump body outlet.

The degassed liquid returns to the storage chamber and enters the impeller again through the reflux hole, where it mixes with the gas sucked in from the suction pipeline inside the impeller. Under the action of the high-speed rotating impeller, it flows towards the outer edge of the impeller again. As this process repeats itself, the amount of air sucked into the pipeline continuously decreases until the gas is completely absorbed, completing the self-priming process, and the pump is put into normal operation.

Some pumps also have cooling chambers at the bottom of their bearing bodies.

When the bearing heats up and causes the temperature of the bearing to rise by more than 70 degrees, coolant can be injected into the cooling chamber through any coolant pipe joint for circulation cooling. The sealing mechanism inside the pump to prevent liquid leakage from the high-pressure area to the low-pressure area is the front and rear sealing rings.

The front sealing ring is installed on the pump body, and the rear sealing ring is installed on the bearing body. When the sealing ring wears out to a certain extent after long-term operation of the pump and affects the efficiency and self-priming performance of the pump, it should be replaced.