Picking A Pump: What You Should Know About Self-Priming Centrifugal Pumps

Centrifugal pumps from sites like http://pfcequip.com/ are designed to move liquid through a system. Most centrifugal pumps are not capable of handling gasses or other materials. Because these pumps are not able to handle gasses, it is important that the pump is primed so that there is no air in the pump's first stage before you start it. Otherwise, the system may not flow properly. Here is some information about choosing a self-priming pump and keeping it running at its best.

Understanding Self-Priming Pumps

A self-priming pump is one that is designed to free itself of any air pockets. These pumps typically operate independently, free of any manual intervention to prime the system or clear out gas pockets. If you are interested in investing in self-priming pumps for your system, here are the types available on the market.

Liquid-Priming Pumps

A liquid-priming pump depends upon a chamber filled with liquid for the pump to prime the system. In this process, air pockets are drawn out of the pump, creating a suction that replaces the air with liquid from the reservoir.

Once the front chamber of the pump is filled with liquid, the system will be able to operate at standard capacity for the pump you have installed. If you work in an area where temperatures drop below freezing, and the pump is installed outside, add a heating element to the reservoir to prevent freezing.

Compressed Air Priming Systems

Unlike liquid priming pumps, a compressed air priming system uses high-pressure compressed air running through a tube to prime the pump. The air creates a vacuum in the tube system that draws fluid into the pump. Gradually, the fluid overtakes the air in the pump. When this happens, the pump is able to run as needed.

Vacuum Priming Pumps

A vacuum-primed pump system uses a float box to establish a vacuum. That vacuum draws liquid into the pump until it has enough for the pump to cycle properly. Some vacuum-primed pumps can even run dry for very brief periods. This is beneficial because it gives you time to restore the system if something should malfunction.

Efficiency Improvements

Once you have chosen and installed a self-priming centrifugal pump, it is in your best interest to optimize the system. For example, installing a foot valve on the pump's suction line will allow you to keep the pump full of fluid even if it's not running.

Add a water ejector to the systems discharge pipe in order to create a consistent draw to prime your pump. In situations where you are using submersible pumps, this keeps the system flooded and preserves the prime.

If you want to avoid the buildup of air in the pump lines in the event of a main pump failure, place a self-priming pump on the discharge side of the system's main pump. By doing this, you'll be able to run the self-priming pump to maintain the prime if your main pump fails.

Safety Considerations

No matter which type of centrifugal pump you choose, it will need routine inspection. Monitor the pump for any signs of air leaks. One of the biggest problem areas for leaking is the pump shaft seal. Check this seal frequently so that you can spot a leak right away.

You should also be sure that the suction pipe is free of any high spots. If the pipe isn't level, you're bound to have air pockets and inefficient flow.

Once you understand the different types of self-priming pumps and how to keep them running their best, you'll be able to choose the most effective pump for your system and keep it flowing at optimal capacity. Talk with a centrifugal pump technician if you want professional support to choose and install your new pump.