Progressive cavity pumps are effective for certain applications and fluids. However, they are not ideal for every application, which is something that can generally be said for most different types of pumps. Proper pump selection is always critical. You have to find, configure and operate the right pump system to produce the optimum results for your specific fluid processing application.
How Does a Progressive Cavity Pump Work?
It helps to understand the basic operating principles of a progressive cavity (PC) pump. An internal rotor is generally made from a solid piece of metal, and its shape is a single-helix that rotates within a double-helix-shaped cavity. The rotation creates suction that effectively pulls the process fluid through the pump.
Progressive cavity pumps are often utilized for applications where the fluid viscosity levels are beyond what a standard centrifugal pump can efficiently handle. PC pumps might also be effective when the process fluid is abrasive or shear sensitive. A good example might include food production, such as solid fruits suspended in a liquid that you don’t want to be sheared as they travel through the pump.
Progressive Cavity Pump Selection
Three key factors to consider when selecting the best progressive cavity pump for your application are:
- Fluid Properties
- Pump Size
- Operating Speed
- Pump Stator/Rotor Material
- Pressure:Flow Rate Ratio
Let’s take a look at each of these factors interact:
Know Your Fluid
It is key to understand your fluid(s) before deciding if a progressive cavity pump is the proper selection. Then, the fluids’ physical qualities will help you determine the pump size, operating speed, and material. The main fluid factors to focus on will be the temperature, viscosity, and abrasive qualities.
The higher the viscosity, the lower the operating speed of the pump should be. Therefore, abrasive fluids will generally require a larger progressive cavity pump that can run at lower speeds. A smaller and faster PC pump may not be as efficient and the wear from the abrasive fluids will cause costly problems over time.
Additionally, the temperature will affect the performance and durability of the stator elastomer. As fluid temperatures increase, the elastomer stator will expand. Therefore, the stator material must be matched to the fluid temperature to produce the desired pumping results.
Pressure vs. Flow Rate
In general, a progressive cavity pump is an effective solution when the pressure required is higher than the flow rate (PSI > GPM). Operators often avoid using PC pumps because they are typically most efficient at lower speeds—it seems counterintuitive to have a slower pump. However, viscous, abrasive, and temperature-sensitive materials can cause problems in other pumps that may offer higher flow rates and speeds. Like the tortoise versus the hare, sometimes slow and steady is what you actually need to win the race!
SEEPEX Progressive Cavity Pump
SEEPEX is one of the world’s leading manufacturers of progressive cavity pumps. They offer an excellent selection of PC pumps with different sizes, materials, and speeds to suit your specific needs. Consider a SEEPEX pump if a progressive cavity solution is best for your operation.
To learn more about SEEPEX progressive cavity pumps and help selecting the ideal pump size, material and speed for your particular application, contact DXP Pacific today. Let our knowledgeable team provide guidance and advice to ensure proper pump selection.