treated water centrifugal pump

Self-Priming Pumps: Pros and Cons

Centrifugal pumps need to be primed before they can be operated. Even though priming is needed only when the elevation of the liquid in the suction tank or pond is less than that of the pump, it is still best to prime the pump first before operating it.

Priming every single time can be a tedious process and this can be eliminated by using a self-priming pump. Learn about the advantages and disadvantages of self-priming pumps to see if they’re suitable for your operations.

An overview of self-priming pumps

A self-priming pump usually uses a vacuum priming system to ensure that your pump is always ready to start without any troublesome start-up procedure. It eliminates the problem of your pump losing its prime or becoming air-bound.

You cannot operate a self-priming pump without water. It overcomes air binding by mixing water into the air. Once the self-priming pump gets rid of air, it continues to move water just like anh standard centrifugal pump.

Self-priming pumps can effectively handle different kinds of fluids and they are great with corrosive fluids, slurries and solids.

Advantages of self-priming pumps

engineering inspecting the machineThere are many benefits that come with the priming system used by self-priming pumps. For one, a well-designed vacuum priming system can prime multiple pumps, so installation costs are lower and the run-time is limited. It also ensures that all pumps are fully primed and lets you use the most efficient and reliable pumps at the lowest cost. Since the priming system is mostly a non-wetted component, it does not need expensive construction materials, and ultimately reduces your construction and equipment expenses.

Since you do not have to wait until a self-priming pump to finishes priming for it to be usable, you can maximise the efficiency of your pump at reduced power requirements. You will be able to skip tedious and time-consuming start-up procedures for centrifugal pumps, and the glitches that come with it. By mixing air and water, a self-priming pump eliminates the need to fill it and the suction piping with water. There’s no need for unreliable but expensive foot valves either.

Perhaps, the most prominent advantage of a self-priming pump is its ability to handle solids. Some pumps can even handle solids up to 8 centimetres in diameter. Compared to a submersible pump, a self-priming pump can also continue to pump fluids while it is still out of the pit.

Disadvantages of self-priming pumps

The main problem in a self-priming centrifugal pump tends to happen towards its suction side. For new self-priming pumps, the standard priming process needs to be followed before you can put it into use. After the initial priming, you need to prime it again to optimise its operation due to many factors, such as the evaporation of fluids during its initial priming.

A self-priming pump’s suction line is below atmospheric pressure, which makes it prone to air leakage. Ideally, the suction line should be at 0.5 metres of vacuum during the operation of the pump.

You also need to place the self-priming pump as close as possible to its suction source. The maximum recommended distance usually ranges from 7.6 to 9 metres.

Self-priming pumps eliminate the tedious process of priming before a centrifugal pump is operational. Its priming system and function lead to many benefits, but has disadvantages, as well. Weigh its pros and cons, and consider your application and other relevant factors to decide whether or not self-priming pumps are suitable for you.