china slurry pump valve

Self Priming Pumps: How it Works, Types, and Applications

What Is Self-Priming?

Pumps that are partially or completely above the fluid level allow air into the suction line, which must be evacuated or displaced before the pump can move the liquid. Self-priming pumps are capable of removing air at startup before beginning its normal pumping functions.

Are Centrifugal Pumps Self-Priming?

Centrifugal pumps do not have seals between the suction and discharge sides of the pump, meaning they are not self-priming and cannot evacuate gases and air if the pump is above fluid level. To make a centrifugal pump self-priming, it can be surrounded by a tank to ensure that it is always immersed in a liquid and that it has the necessary lubrication and cooling to prevent the pump from overheating.

How Do Self-Priming Pumps Work?

To avoid the mixing of air and water, self-priming pumps create a partial vacuum to discharge water while also evacuating any air. It does this by combining the air and water during the priming process, forcing the air to rise and the water to sink or go down. Gravity then pulls the air-free water back into the impeller, where it mixes with the remaining air in the suction line.

This process repeats until all air is evacuated and a vacuum forms in the suction line. Once this happens, atmospheric pressure forces the water into the suction line and towards the impeller to allow pumping to begin.

Common Applications

Self-priming pumps are used in various industrial and commercial facilities, from steel mills, power plants, and sewage treatment facilities to wineries, breweries, and more. Common applications include:

• Pumping water, fuels, clear or gray water, raw sewage, industrial wastewater, and more
• Liquid transfer systems
• Irrigation
• Basement floodwater pumps
• Bailing out boats
• Increasing water pressure
• Sewage treatment

FPS Self Priming Pumps

FPS self-priming pumps are built to handle clear water and solids. They can handle solids up to 3 inches in diameter or length, and the pumps are built with self-priming mechanisms to mitigate the risk of becoming air-bound. At GIE, we provide FPS self-priming pumps in electric drive, frame mount drive, and gas engine drive varieties. Gas engine varieties can provide up to 27 horsepower, depending on the model.

Gould Pumps Clear Liquids Self Priming End Suction Pumps

These self-priming pumps can handle clear water for a variety of commercial and industrial applications. They are available in portable contractor pump styles, with enclosed impellers, and with bronze fittings to integrate with virtually any applicable system. Gould’s self-priming end suction pumps can handle up to 250 PSI and fluid temperatures of 250°F.

Marlow Series Self-Priming Pumps

These self-priming pumps are designed to be placed anywhere from 10 to 20 feet above the fluid level without the risk of becoming air-bound. Along with clear water, they can handle solids of different sizes depending on the specific model chosen. Marlow specializes in vertical in-line pumps that can be used in industrial petroleum and chemical systems.