Understanding the Key Differences: Self-Priming Pump vs. Non-Self-Priming Pump

Self-Priming Pump

A self-priming pump is designed to remove air from the suction line and create a vacuum that allows the pump to draw fluid from a source. Unlike traditional pumps, self-priming pumps can operate without external assistance or the need for a foot valve.

This makes them perfect for applications where the pump is located above the fluid source or where the fluid supply is intermittent. Self-priming pumps are commonly used in wastewater treatment, irrigation, and other industrial applications. They are typically centrifugal pumps with a particular chamber or mechanism that allows them to create the necessary vacuum for priming.

The Inner Workings of a Self-Priming Pump: An In-Depth Explanation

Self-priming pumps are designed to have the necessary liquid in their chamber or body during start-up. They prevent mixing air and water by creating a partial vacuum to discharge water. Through the priming process, air and water combine, allowing the air to rise and the water to descend. Gravity then pulls the air-free water back into the impeller, mixing it with the remaining air in the suction line.

This cycle continues until all air is removed and a vacuum is created in the suction line. Finally, atmospheric pressure pushes the water into the suction line and towards the impeller, initiating the pumping process. By mixing any remaining air in the working mechanism with fluid during priming, self-priming centrifugal pumps can overcome air binding.

Self-Priming Pump

Non-Self-Priming Pump

A non-self-priming pump requires external assistance to remove air from the suction line and create a vacuum, allowing it to draw fluid from a source. Unlike self-priming pumps, non-self-priming pumps cannot operate without a constant fluid flow and a foot valve to maintain the necessary vacuum for priming. This makes them less suitable for applications where the fluid source is intermittent, or the pump is above it.

These centrifugal pumps are commonly used when a steady liquid flow is required, such as in chemical processing, water treatment, and circulation systems. They are also typically centrifugal pumps but lack the special chamber or mechanism that enables self-priming pumps to create the necessary vacuum for priming.

The Mechanics Behind a Non-Self-Priming Pump: A Comprehensive Overview

A non-self-priming pump operates differently than a self-priming pump. It relies on external means to fill the pump with liquid before it begins operation.

When a non-self-priming pump is turned on, the impeller inside the pump begins to rotate, creating a vacuum effect that draws liquid into the pump casing. However, this process will only work effectively if the pump casing is filled with fluid.

To ensure that the pump casing is filled with liquid, the non-self-priming pump must be installed below the liquid level, or a separate priming mechanism must be used to fill the pump before it starts. This is typically done using a foot valve installed at the end of the suction line and prevents the liquid from flowing back out when the pump is switched off.

While a non-self-priming pump requires additional steps to ensure proper operation, it can still be an effective option for many applications, mainly when used with the appropriate priming mechanism.

Self-Priming Pump

Self-Priming Pump vs. Non-Self-Priming Pump: What Sets Them Apart?

Non-self-priming Pumps

  1. Self-priming is not a feature of standard centrifugal pumps, also called non-self-priming pumps. Instead, these pumps require external priming to ensure they are filled with liquid before operation.
  2. Standard centrifugal pumps operate by using centrifugal force to move water. Water enters the pump through a suction inlet, passes through one or two impellers, and is propelled toward the pump discharge. The impeller(s) are designed with curved blades that rotate at high speeds to generate the centrifugal force necessary for moving water. This process is repeated continuously to create a steady flow of water.
  3. As standard centrifugal pumps are not self-priming, priming must be done manually by ensuring the intake pipe is always filled with liquid before the pump is operated. This process involves filling the pump and suction pipe with liquid, which displaces any air, to create a vacuum in the suction line. This vacuum draws in more fluid until the entire system is primed and ready for operation. It is crucial to ensure the pump is correctly primed to prevent damage to the pump and ensure optimal performance.
  4. Compared to self-priming pumps, standard centrifugal pumps are valued for their simplicity, durability, and affordability. We have extensive experience as manufacturers of centrifugal pumps, which allows us to offer a diverse range of high-quality pumps. Our centrifugal pumps are designed and built to meet the demands of various industries and applications. Explore our range of centrifugal pumps to learn more about our offerings and how they can benefit your pumping operations.

Self-Priming Pump

Self-Priming Pumps

  1. Unlike standard centrifugal pumps, self-priming pumps are designed to prime themselves automatically and do not require any manual priming procedures. This feature makes self-priming pumps popular for applications where frequent priming takes time and effort. In addition, self-priming pumps use a unique mechanism to create a vacuum and draw in the liquid, eliminating the need for external priming. This makes them efficient and user-friendly for a wide range of pumping applications.
  2. Self-priming pumps are designed with a distinct feature of an integrated liquid reservoir positioned above or in front of the impeller. This design lets the pump prime itself automatically and starts pumping without manual priming. In addition, the liquid reservoir helps maintain sufficient liquid in the pump, allowing it to create a vacuum and pull in the liquid for efficient pumping. This design feature makes self-priming pumps a popular choice for applications where priming would require more time and effort.
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  4. One of the notable advantages of self-priming pumps is that they do not require a foot valve. This is because the integrated liquid reservoir allows the pump to remove any air from the pump body and suction line during the priming cycle, replacing it with a mixture of liquid and any remaining air. This makes self-priming pumps more efficient and user-friendly than other pumps requiring a foot valve for proper operation. Self-priming pumps are commonly used in applications where frequent priming is needed or when the pump must be restarted after a power outage or system shutdown.


The main differences between self-priming and non-self-priming pumps lie in their design and operation. Self-priming pumps have an in-built liquid reservoir and can prime themselves without manual intervention, while non-self-priming pumps require manual priming before use. As a result, self-priming pumps are ideal for applications requiring frequent priming and are more reliable and efficient in such situations.

In contrast, non-self-priming pumps are more straightforward and cheaper, making them a better choice for less demanding applications. Ultimately, the pump’s intention depends on the application’s specific needs and operating conditions, and careful consideration should be given to ensure optimal performance and efficiency.

Self-Priming Pump

Self-Priming Pump

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