SELF-PRIMING CENTRIFUGAL PUMPS

What are Self Priming Centrifugal Pumps?

Centrifugal pumps can process liquids, gasses, and abrasive liquids. Their processing power makes them ideal for venting the air in the suction line. However, these pumps only function if the liquid head balances the local air pressure.

It will stop operating as soon as one of the air pressures overcomes the other. For instance, these pumps can perform perfect priming for a 10m height. But factors like temperature and altitude can reduce this efficiency.

Self Priming Centrifugal Pumps

The centrifugal pumps use rotation energy from rotors to move the liquids across the impeller and liquids. In addition, you will not find any seals between the suction and the outlet discharge of the pump. Thus, you can use these pumps to process gases as they do not have any openings.

Trapped air can be dangerous, leading to overheating, component wear, and several other mechanical issues. Mechanical failure can have a long-term pump performance impact too. The pumped liquid usually lubricates the pumps, which does not occur in the case of processing gases.

You can always immerse the pump underwater because the impeller and volute have a casing stopping water contact. It also provides the pump with the cooling and lubrication necessary for optimal performance. However, the priming time should not be too extensive, or we may not get the desired results.

Self-priming mainly means that the pump uses stored liquid in its reservoir to lubricate and cool the components. Remember that a self-priming pump does not work without moisture or if it is dry. 

You can add specific bearing to make the pumps work in dry conditions, but it doesn’t last long.

How does a Self-Priming Centrifugal Pump Work?

The self-priming centrifugal pump works like a liquid-ring pump during its priming phase. The impeller in the pump creates a vacuum by sucking the air in the suction line.

The pump casing acts as a liquid ring simultaneously, creating a gas-tight seal and preventing any gas from leaking out. The air bubbles get trapped in the system and leave the pump from the discharge port located on the other end.

The liquid rises in volume gradually, and reaches the suction line as it evacuates. The pumping starts at this point, and the liquid starts exiting from the pump. The pump saves liquid to avoid running dry in the future.

Bottom Line

The self-priming centrifugal pumps are perfect for users who want to maintain a consistent fluid pumping through the machine. Ensure reading all about these self-priming centrifugal pumps or consulting with a professional to ensure you operate them the right way.