Self priming centrifugal pump

self-priming pump is a modified type of centrifugal pump, differing from
conventional centrifugal pumps that require manual priming and air venting before
startup. With its built-in liquid reservoir due to its structural design, the self-
priming pump eliminates the need for repeated water filling after the initial
priming. It can automatically draw liquid from below the pump's installation
position, preventing air binding. This type of pump is widely used in scenarios
such as water supply and drainage, garden irrigation, sewage lifting, chemical
dosing, and on-site pumping, where low-position pump installation or frequent
start-stop cycles are impractical.
2、 Working principle
1. First use: Add water intake
Fill the storage chamber of the pump body with liquid and close the exhaust port
before the first operation, leaving a certain amount of working fluid in the
storage chamber.
2. Gas liquid mixture suction stage
The impeller rotates at high speed, throwing the water retained in the pump body
towards the volute, creating negative pressure at the impeller inlet; The air in
the suction pipeline mixes with the water in the pump at high speed, forming a
mixture of gas and water, which is continuously pressed towards the gas-liquid
separation chamber.
3. Gas liquid separation
The gas water mixture enters the upper part of the separation chamber, and the gas
with low density is discharged from the exhaust port. The liquid falls back to the
lower storage chamber of the pump by gravity to participate in gas-liquid mixing
circulation.
4. Normal water delivery
As the air inside the pipeline is continuously emptied, a vacuum is formed in the
suction pipeline, and the liquid level is continuously sucked into the pump under
atmospheric pressure. The self-priming process is completed, and the pump enters
the conventional centrifugal pump water delivery condition.
Core feature: After the first addition of water, sealing water will remain inside
the pump casing, and there is no need to refill the pump again after subsequent
shutdown and restart.
3、 Main structure
Self suction pump body (with gas-liquid separation storage chamber): Different from
ordinary centrifugal pump volutes, the upper part is designed with a large capacity
air-water separation chamber to store water and separate air;
Impeller: mostly closed impeller (for clean water self-priming pumps), open/double
channel impeller (for sewage self-priming pumps);
Check valve (bottom valve/one-way valve inside the pump): Lock the water storage
inside the pump after shutdown to prevent water from flowing back into the suction
tank, ensuring that it can still self suction next time;
Exhaust plug and water inlet: add water for the first time and empty the air inside
the pump;
Mechanical seal, motor, base.
4、 Main classification
1. According to the conveying medium
Clean water self-priming pump
Made of cast iron/stainless steel material, with a closed impeller, used for
boosting tap water, irrigating farmland, and circulating water supply. It can only
transport clean water and cannot contain a large amount of fiber sediment.
Non clogging sewage self-priming pump
Double channel/cutting impeller, can transport domestic sewage, mild sludge, and
wastewater containing a small amount of fiber, mostly used for construction site
sewage discharge and small-scale sewage treatment plants.
Corrosion resistant self-priming pump (fluoroplastic/stainless steel)
Transporting acid and alkali, chemical waste liquid, and electroplating wastewater,
mostly used for environmental protection dosing and chemical liquid transportation.
2. According to the structural form
Horizontal self-priming centrifugal pump (ZX, ZW type): commonly used in industry,
with stable self-priming and a wide range of head and flow rate;
Vertical self-priming pump: small footprint, directly connected pipeline
installation;
Household small self-priming booster pump: 220V single-phase, used for boosting
household tap water and taking well water.
3. Follow the self-priming method
Internal mixing self-priming pump: gas-liquid mixing occurs inside the impeller,
with fast self-priming speed and a self-priming height of generally 4-6m;
External hybrid self-priming pump: Gas and liquid are mixed on the outside of the
impeller, with a simple and durable structure, commonly used in high flow
conditions.
5、 Core performance parameters
Self suction height: the most critical parameter, the rated self-priming height of
a conventional self-priming pump is 4-6 meters (it is recommended not to exceed 5
meters in practice), which refers to the maximum vertical height from the center of
the pump to the suction liquid level;
Flow rate, head, rated power voltage;
Self suction time: Generally completed within 30-120 seconds, exceeding the time
indicates air leakage or water loss;
Medium temperature: conventional 0-80 ℃.
6、 Advantages
One time water filling, multiple start and stop without filling the pump, solves
the problem of frequent pumping of ordinary centrifugal pumps, and eliminates the
problem of gas binding and inability to suck water;
Flexible installation, can be installed on the ground or at high places, without
the need to place the pump below the liquid level or build a pump room;
It can suck liquids containing a small amount of gas, and the pipeline can still
work normally even with slight air intake;
Easy to maintain, highly versatile, with multiple working conditions to choose from
for clean water, sewage, and chemical anti-corrosion.

Minimum Order: 1 sets

Click to Enlarge