When is a Screw Pump Better than a Centrifugal Pump?

Pumping technology continues to evolve, with more and more specialized pump systems available for specific applications. Centrifugal pumps have been the standard for many industries for many years. However, more and more operators are looking for screw pumps to handle certain materials.

Differences Between Centrifugal and Screw Pumps

Centrifugal pumps utilize an impeller design that is great for high-transfer applications and water-like fluids that need to be pumped through piping networks with variable flow rates. With their engineering principals, it’s easy to understand why so many operators depend on centrifugal pumps for a variety of common fluid processing applications. Yet, we all know that different pumps are often better for different jobs.

Screw pumps are becoming increasingly popular in certain industries where standard centrifugal pumps just aren’t providing the desired flow rates and energy efficiency, or they are having trouble handling high-viscosity liquids and other materials that tend to hinder performance capabilities.

Twin screw pumps and triple screw pumps feature a positive displacement design that has proven to be more versatile and reliable for certain applications—especially in industries like chemical processing, petrochemicals and oil and gas, where viscosity is often a problem for centrifugal pumps.

Disadvantages of Centrifugal Pumps

Operators often lean on centrifugal pumps because of familiarity. These are the pumps they are used to working with and they find ways to adapt them for different performance requirements. They know how centrifugal pumps operate and have adapted their processes to pump what they need to pump. We often see oil processing plants who will blend or heat the crude oil in order to reduce viscosity before it goes through the centrifugal pump system. This is a common practice, but it may be an unnecessary step. What if you could eliminate the heating or blending stage by simply installing a pump system that will better handle the viscous raw fluids?

The truth is, centrifugal pumps rarely operate at their Best Efficiency Point (BEP) because they are being adapted, adjusted and used for applications for which they may not be ideally suited. Meanwhile, screw pumps might provide the desired performance for high-viscosity fluid transfer without having to make these other sacrifices. 

Advantages of Screw Pumps

Screw pumps contain multiple screws that engage with one another as rotated to form a sealed cavity within the pump casing. As the screw drives turn, the fluid shifts steadily and constantly through the pump. It creates a volumetrically consistent flow rate that is unaffected by pumping pressure or viscosity that might slow down a centrifugal pump.

Some screw pump advantages include:

  • Versatility with different flow rates, pressures, liquid types and viscosities
  • Constant flow rates
  • High volumetric efficiency
  • Controllable output
  • Low internal velocities
  • High tolerance for entrained gases or air
  • Smooth and quiet operation
  • Very low pulsation
  • Self-priming characteristics
  • Reduced mechanical vibration

Best Screw Pump Manufacturers

DXP Cortech works with some of the world’s leading manufacturers of screw pumps. We have great screw pumps from companies like INOXPA and Circor IMO. These screw pumps can be utilized for a wide variety of fluid applications, so it is important to find the right pump for your specific fluid transfer needs.

Contact DXP Cortech today to learn more about the advantages of screw pumps and to see if one is the right solution for your industrial operation. Let us help you select, install and maintain the best pump for the job!