What Is a Progressing Cavity Pump?

Mary McMahon
Mary McMahon

A progressing cavity pump is a type of pump useful for liquids and slurries with a range of viscosities. This design features a rotor in a helical shape mounted inside a sealed container. As the rotor turns, it pulls the fluid up into the container in a series of isolated cavities, discharging it out the other end. The design is also known as an eccentric screw pump, as it looks similar to a corkscrew inside the container, or as a Moineau pump, for the French inventor who first developed it.

Progressive cavity pumps are a type of screw pump and operate in a twisting motion.
Progressive cavity pumps are a type of screw pump and operate in a twisting motion.

The progressing cavity pump is an example of a positive displacement pump, functioning to move a fluid from one location to another by trapping it. This pump does not need priming, as it does not rely on maintaining pressure to operate, and it can handle very low flows and very thick materials, as the rotor acts mechanically to pull fluid up until it reaches the discharge pipe.

This pump design can be useful for waste-water management facilities and a variety of other environments where fluids may have suspended sediments. The rate of flow is adjustable by changing the speed of rotor rotation, allowing an operator to decide how much fluid to move in a given time period with a progressing cavity pump. Maintenance requirements include lubricating the rotor shaft, periodically cleaning intake and outlet pipes to remove obstructions, and confirming that the seal is still tight.

Manufacturers with progressive cavity pump lineups usually feature a range of sizes and speeds for different applications. For customers unsure about the best model for their purposes, it can help to ask a company representative for advice and assistance. It is important to select a pump capable of handling a given flow rate and to consider future pumping needs; if volumes are likely to increase, for example, buying a pump rated for the current application will not be sufficient, as it will start to overload when the volume goes up.

It is sometimes possible to rent a progressing cavity pump for a specific application or to use in a trial to see if it will meet the need. Companies may also offer leases and sales of used pumps to provide consumers with more options. For companies that want to buy a new unit, the manufacturer may offer periodic deals for new customers that can lower the price and make the progressing cavity pump more affordable.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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