What Are Self-Priming Pumps & How Do They Work?

Self-priming pumps are essential in a variety of industries and applications. They differ from traditional centrifugal pumps in that they can draw liquid from a suction source and pump it without the need for manual filling or priming. Because of this, they are a popular choice for applications where a steady supply of water is not readily available. This article aims to provide a comprehensive overview of self-priming pumps, from their basic principles of operation to their practical applications in various industries.

What is a Self-Priming Pump?

A self-priming pump is a type of centrifugal pump that can draw liquid from a suction source and pump it without needing to be primed manually. Unlike traditional centrifugal pumps, which require you to manually fill them with liquid before starting, self-priming pumps have a built-in mechanism that allows them to remove any trapped air and create a vacuum so that they can begin pumping fluid from the suction source. For a self-priming pump to work effectively, there must be liquid in its housing or cavity.

Working Principle

The automatic priming capability of self-priming pumps is due to the ability of their reservoirs to retain water after the first prime. During pump priming, air enters the pump from the suction line and combines with liquid at the impeller to create a pumping fluid. The impeller rotates very fast to create a vacuum, which forces air to rise to the top and pushes the liquid down into a reservoir inside the pump housing. The liquid becomes denser after being separated from air bubbles and flows back into the impeller chamber. In the impeller chamber, the liquid combines with the remaining air in the suction line. This process repeats itself until the pump expels all the air and becomes filled with fluid. As soon as the pump is filled with liquid, it begins the normal pumping process, expelling liquid.

Pros & Cons

Here are the major pros and cons of self-priming centrifugal pumps:

Pros

• They can handle various liquids, including corrosive liquids, suspended solids, and slurries.
• The pump keeps pumping liquids even after taking it out of the liquid tank or vessel.
• Because they do not require priming, self-priming pumps are ideal for both frequent and intermittent pumping operations.

Cons

• Self-priming pumps can’t operate if there is no initial priming liquid in their reservoir.
• They are larger than other centrifugal pumps because they need a liquid reservoir to function. This can cause issues when space is limited in the liquid tank.
• They must be close to production lines to ensure that the pump’s liquid reservoir doesn’t deplete during the self-priming process.

Common Applications

Self-priming industrial pumps are suitable for use in various applications, including:

• Irrigation and agriculture
• Wastewater treatment
• Flood control and dewatering
• Swimming pool and spa circulation
• Industrial processes, such as chemical transfer, water treatment, and cooling towers
• Firefighting and emergency pumping
• Marine and saltwater transfer
• Mining and construction site dewatering

Self-Priming Pumps vs. Centrifugal Pumps

The differences between self-priming pumps and centrifugal pumps are as follows:

1. Priming: Self-priming pumps can draw in and pump liquid from a source without the need for manual filling, while centrifugal pumps require you to manually fill them before they start pumping.
2. Suction Lift: Self-priming pumps are capable of lifting fluid from a level below the pump, while centrifugal pumps can only lift liquid from the same level as the pump or above it.
3. Efficiency: Centrifugal pumps are generally more efficient than self-priming pumps, as they are designed to move fluid at a constant flow rate.

Contact PumpWorks for Your Pump Needs

Look no further than PumpWorks for all your pumping needs. Our state-of-the-art pumps are designed to make fluid transfer easy, efficient, and hassle-free. In addition, our advanced priming pumps are designed to eliminate the need for manual priming. Contact us now to learn more about our range of industrial pumps.