Understanding Progressing Cavity Pumps

Introduction

Progressive Cavity Pumps, also known as Positive Displacement Pumps, deliver a nearly constant flow rate at a given operating speed, even when there are fluctuations in the counter-pressure.

There are two primary categories of Progressive Cavity Pumps:

Rotary Pumps
Reciprocating Pumps

How Does the Flow Compare for a Given Back Pressure Variation

The diagram illustrates the contrasting behavior of centrifugal pumps, rotary pumps, and reciprocating pumps in response to changes in back pressure.

Centrifugal pumps
A change in back pressure causes a much more significant change in flow.
Find out more on centrifugal pumps here.
Rotary pumps
A change in back pressure leads to a slight change in flow.
Reciprocating pumps
A change in back pressure has minimal impact on the actual flow within the pump’s operating range.

The diagram illustrates the contrasting behaviour of centrifugal, rotary and reciprocating pumps in response to changes in back pressure (𝚫H).
The flow rate of centrifugal pumps changes the most (Q=1), while that of rotary pumps changes only slightly (Q=2) and that of reciprocating pumps hardly changes at all (Q=3).

How to read pump curves.

Let’s have a look at the different pumping techniques, which ensure that the movement of the fluid is in proportion to the speed of rotation of the pump.

Rotating Progressive Cavity Pumps

Rotating progressive cavity pumps are mainly used for higher viscosity or loaded fluid transfer.
In their smaller versions, they are used as dosing and metering in manufacturing processes.
Here are the main types:

Eccentric Screw Pump

Utilises a helical rotor turning within a stator, creating cavities that progress from the suction to the discharge end. See how Eccentric Screw Pumps works
Ideal for handling viscous, shear-sensitive, and particulate-laden fluids.
Used in many applications as wastewater treatment, food processing, chemical industry, biogas, oil and gas and more.

Lobe Pump

Uses two rotating lobes that trap and transfer the fluid through the pump. Known for gentle handling of fluids, making them suitable for food, pharmaceutical, and cosmetic industries.
Some bigger lobe pumps use helical lobe design.
Used in food and beverage, pharmaceuticals, biotechnology, cosmetics, biogas.

Korthaus Pumps

Screw Pump

There are different types of Screw Pumps, namely double and triple screw pumps.
Double screw pumps are used to move delicate fluids as fruit, meat…
Excellent for high-viscosity fluids and applications requiring a smooth, pulsation-free flow.
Triple screw pumps are used in the transfer of oil and other lower viscosity fluids.
Food and beverage, chemical processing, Oil and gas, marine…

Wangen Twin Pumps

Gear Pump

Consists of two meshing gears that displace fluid through the pump. Available in external and internal gear configurations, they are best for transferring oils and other lubricating fluids.
In Food, used for heated products like chocolate, chemical processing, hydraulics, fuel transfer, but also heated bitumen, oil and lubricants…

More on Gear Pumps

Rotary Vane Pump

Features a rotor with vanes that slide in and out to trap and move fluid. Often used in applications requiring a consistent flow rate, such as fuel transfer and refrigeration.
Fuel transfer, refrigeration, automotive, aerospace.

These pumps, each with its own unique mechanisms, are tailored to specific industries and applications, ensuring optimum performance and efficiency for different fluid handling needs.

Reciprocating Progressive Cavity Pumps

Reciprocating pumps, as we have seen in the diagram above, offer excellent flow stability in relation to the variation in back pressure that a manufacturing process can induce. This makes them ideal for more accurate dosing and metering, particularly in the lower flow ranges.
Here is a quick overview of the different piston pump technologies.

Diaphragm Pump

Fluid is displaced by a reciprocating diaphragm, creating a variable volume within the pump chamber. Ideal for dosing applications.
More on Diaphragm Pumps.
Ideal for high accuracy dosing in water distribution, chemical transfer, pharmaceuticals, food processing, wastewater treatment.

Air-Operated Double Diaphragm (AODD) Pump

Powered by compressed air, with two diaphragms that move back and forth to pump fluids. Highly versatile, capable of handling a wide range of fluids including corrosive and abrasive materials.
Ideal in chemical transfer, mining, wastewater treatment, food and beverage.

Peristaltic Pump

Fluid is moved through a flexible tube squeezed by rotating rollers or shoes.
Ideal for sterile and contamination-free pumping, in their smaller versions, it is often used in medical and chemical applications for fluid dosing.
In their bigger version, they can transfer easily heavy loaded fluids very gently.
In their smaller versions, medical devices, pharmaceuticals, chemical dosing, food and beverage.
In their bigger versions, mining, wastewater treatment, chemical processing, pulp and paper, biogas and even live fish transfer.

Piston Pump

Employs a piston moving back and forth in a cylinder to displace fluid.
Common in high-pressure applications such as hydraulic systems and pressure washing.
Hydraulics, pressure washing, industrial cleaning, water jet cutting.

SPS Pumps
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Extensive Industrial Knowledge
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We leverage this knowledge to guide you towards the optimal pump selection or identify the exact spare parts you require, ensuring efficient and reliable operation.

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Progressive Cavity Pumps