Progressive Cavity Pumps

Progressive cavity pumps are positive displacement pumps designed for reliable transfer of viscous, abrasive, shear-sensitive and solids-containing fluids. Also known as progressing cavity pumps, PC pumps or helical rotor pumps, they produce a smooth, low-pulsation flow and can be accurately controlled by varying pump speed.

AxFlow UK supplies NOV Mono progressive cavity pumps for applications including wastewater and sludge handling, food and beverage processing, chemicals, industrial processing and hygienic product transfer. Our engineers can help select the pump, rotor and stator materials, drive arrangement and protection systems to suit the complete operating duty.

What is a progressive cavity pump?

A progressive cavity pump is a rotary positive displacement pump that moves fluid through a sequence of sealed cavities formed between a helical rotor and stator.

Because each rotation moves a predictable volume, flow is closely related to pump speed. This makes progressive cavity pumps particularly useful for controlled transfer, dosing and applications where a steady, low-pulsation flow is important.

They are particularly well suited to liquids that are:

• Highly viscous or non-Newtonian
• Shear-sensitive
• Abrasive
• Containing suspended solids
• Difficult to feed into conventional centrifugal pumps
• Required to be transferred at a controlled or variable flow rate

How do progressive cavity pumps work?

Inside the pump, a single-helix metal rotor rotates eccentrically within a double-helix stator. This creates sealed cavities between the rotor and stator. As the rotor turns, these cavities continuously move from the suction side towards the discharge. The fluid is therefore carried through the pump rather than accelerated by an impeller.

The result is a smooth, positive-displacement pumping action with relatively low pulsation and gentle product handling.

ADVANTAGES OF PROGRESSIVE CAVITY PUMPS 

• Smooth, low-pulsation flow for stable transfer and process control
• Gentle pumping action suited to shear-sensitive fluids and fragile solids (application dependent)
• Excellent for viscous and non-Newtonian media where centrifugal pumps struggle
• Solids handling capability for slurries and sludge duties (range and configuration dependent)
• High differential pressure capability for longer transfer distances (range dependent)
• Variable speed control enables accurate dosing and metering-style transfer
• Good suction performance and self-priming characteristics (duty dependent)

Progressive Cavity pump APPLICATIONS 

Progressive cavity pumps are often used where other industrial pumps struggle, especially when a fluid must be handled gently, contains solids, and/or has high viscosity. Common uses include:

• Pumping, dosing, and metering chemicals where accuracy is required. 
• Hygienic environments and/or shear sensitive fluids such as in the food, drink and cosmetics industry. 
• Pumping materials that contain abrasive particles such as wastewater management and pumping sewage, sludge or slurry. 
• Pumping heavy or viscous fluids such as oil and chemicals. 
• Applications that require varied flow rates.

Which progressive cavity pump should I choose?

The correct pump depends on the fluid and the complete operating duty rather than flow rate alone.

What information is needed to size a progressive cavity pump?

For an initial pump selection, provide:

Fluid or product — including chemical concentration where relevant.
Required flow — minimum, normal and maximum where possible.
Differential pressure — including pipework losses and maximum potential system pressure.
Viscosity — ideally across the full operating temperature range.
Temperature — including start-up and cleaning temperatures where relevant.
Solids — particle size, concentration, shape and abrasiveness.
Suction conditions — flooded suction or suction lift, pipe diameter, pipe length and available NPSH.
Operating pattern — continuous, intermittent or variable-speed operation.
Materials requirements — including corrosion, hygiene or regulatory requirements.
Installation constraints — available space, orientation, access for maintenance and hazardous-area requirements.

Providing this information allows the pump, operating speed, rotor and stator combination, seals and drive to be selected as a complete system.

When Not to Use a Progressive Cavity Pump

Progressive cavity pumps are highly effective for pumping viscous, shear-sensitive and solids-containing fluids, but they are not the best choice for every application. Selecting the correct pump technology is essential to maximise reliability and minimise maintenance.

A progressive cavity pump may not be suitable where:

• Frequent dry running is likely, as the rotor and stator rely on the pumped fluid for lubrication and cooling.
• High-flow, low-viscosity liquids such as clean water are being transferred, where a centrifugal pump is often a more efficient solution.
• Highly abrasive media is pumped at high speeds, as excessive wear can reduce rotor and stator service life.
• Large or fibrous solids exceed the pump's handling capability, increasing the risk of blockage or accelerated wear.
• Intermittent duty with long idle periods is expected, where alternative pump technologies may require less maintenance.

For applications involving clean liquids, abrasive slurries or frequent dry running, technologies such as centrifugal pumps, peristaltic pumps or air operated double diaphragm (AODD) pumps may provide a better solution. AxFlow's engineers can help determine the most appropriate pump technology based on your fluid properties, operating conditions and process requirements.

How do you reduce progressive cavity pump wear?

Rotor and stator wear is strongly influenced by the fluid, pump speed and operating conditions.

For reliable operation:

• Avoid dry running unless the specific pump configuration is designed for it.
• Operate abrasive products at an appropriate speed.
• Maintain stable suction conditions and prevent starvation.
• Select stator elastomers for chemical and temperature compatibility.
• Check the rotor, stator, seals and joints as part of planned maintenance.
• Monitor unexpected reductions in flow or changes in operating performance.
• Use appropriate pressure and dry-run protection where the process creates those risks.

Maintenance intervals should be based on the manufacturer's instructions and the severity of the individual duty rather than a single universal running-hour interval.

WHY BUY PROGRESSIVE CAVITY PUMPS FROM AXFLOW

AxFlow represents Mono progressive cavity pumps that have over 70 years experience.The progressive cavity pump principle is ideal for handling liquids that can be slurries, viscous, shear sensitive, 2 or 3 phase mixtures or when applications require, significant suction lift capabilities. The heart of the Progressive Cavity pump is the rotor and stator. As the single helix rotor revolves eccentrically within the double helix of the stator, a continuous cavity is formed and progresses towards the discharge end of the pump as the rotor rotates