Progressive Cavity Pumps’ ABCDE

What Is a Progressive Cavity Pump?

A progressive cavity pump is a type of positive displacement pump that works on the basis of the progress of the rotor. The helical rotor and rubber-lined stator are the main components of this cavity pump. A progressive cavity pump is a versatile pump that can handle a variety of jobs and is specially designed to meter chemicals and handles highly viscous, abrasive, or shear-sensitive materials and other extremely tough pumping applications.

A progressive cavity pump is widely used. So it has many other different names, such as PC pumps, progressing cavity pumps(PCP), cavity pumps, progg cavity pumps, screw pumps, eccentric screw pumps, etc.

Many famous pump brands are popular with progressive cavity pumps, such as NETZSCH, MONO, SEEPEX, ALLWEILER, MOYNO, etc.. Therefore, there is a big request for replaceable spare parts In the market. Including NETZSCH Pump Parts, MONO Pump Parts, SEEPEX Pump Parts, etc.

What are the specific applications of progressive cavity pumps?

Progressive cavity pumps are versatile and they can be used in different conditions with various applications. Some main PC pump applications are listed below for your information.

• Wastewater
• Pulp and Paper
• Metering and Dosing
• Chemical Manufacturing
• Lubrication Oil Pumping
• Grout or Cement Pumping
• Environmental Technology
• Food and Beverage Processing
• Oil Pumping/Petroleum Production
• Limited Energy Well Water Pumping
• Sewage, Sludge, and Slurry Pumping

How does a progressive cavity pump work?

As a positive displacement pump type, progressive cavity pumps ( also called PC pumps or PCP) are flow-creating devices. They forward fluid at a consistent speed no matter how the pressure varies on the inlet end.

PC pumps draw fluid in through a suction inlet which feeds into an elongated casing. Within the suction casing, there are a helical rotor and rubber-lined stator assembly. The rotor helix is offset to the stator. As the rotor turns and contacts the internal surface of the stator, it leaves conveying spaces between the hollow stator and the helical rotor. Then the viscous medium can move continuously from the inlet to the outlet side. That is generally how a progressive cavity pump works.

Are the PC pumps allowed to dry run?

PC pumps are highly effective at pumping different types of fluids as long as you keep them in ideal working conditions. One main reason for these pumps to fail is when they lose the necessary lubrication to keep the rotor and stators operating correctly.

When there is a loss of lubrication of the pumped fluid, it causes excess friction and high temperature on the surface of the stator. Then the pump stator would be destructed by dry running. Please remember that dry running is the most common cause of pump failure. So PC pumps are not allowed to dry run and we should take some actions to prevent the progressing cavity pump from dry running.

How to prevent the progressing cavity pump from dry running?

Different PC pump manufacturers designed some accessories that act as a safeguard against this. Common methods of preventing the PC pump from dry running are using presence/absence sensors, stator temperature probes, and nonintrusive pressure sensors.

Presence/absence sensors can protect pumps by detecting the absence of fluid flowing into the suction port. When supply fluid is not detected for a preset period of time, the system would deactivate the pump motor starter or other critical process equipment. This sensor is reliable protection against dry running since it can stop the pump before dry running happens.

Stator temperature probes are another way to protect the progressive cavity pump against dry running. Because it has a thermistor sensor and sleeve inserted into the pump stator to measure the temperature between the rotor and stator. When a preset temperature is reached, an electronic temperature regulator would deactivate the motor starter.

For abrasive applications, a few minutes of dry running would result in accelerated wear of the stator. According to our experiences, the rotor and stator actually have a dry run for several minutes before the temperature probes detect the increased heat.

Well, there is another effective way to prevent dry running of the progressive cavity pumps. It is a non-intrusive pressure sensor. This kind of sensor is located at the pump outlet. The pressure detection works over the entire pipe circumference to ensure that coatings, settled material, or bridging will not affect the pressure readings. In addition, a liquid-filled gauge can be an added feature to allow visual monitoring of pressure.

By the way, a pressure sensor not only protects a PC pump from dry running but also prevents pump failure caused by high pressure.

What purposes do progressive cavity pumps serve?

Progressive cavity pumps （also known as PC pumps） are used to pump fluids that cannot be handled by other types of industrial pumps. PC pumps typically serve the following purposes.

• Pumping heavy or viscous fluids;
• Pumping shear-sensitive materials;
• Pumping, dosing, and metering chemicals;
• Pumping materials that contain abrasive particles;
• Pumping fluids in applications that require varied flow rates;

1. Pumping heavy or viscous fluids

The progressive cavity pump is an ideal choice for pumping higher-viscosity fluids. When you use a centrifugal pump, the flow rate would go down as the fluid viscosity goes up. Then it’s far less efficient, as the pump energy consumption must increase accordingly in order to keep up.

Like other types of positive displacement pumps, PC pumps (Progressing cavity pumps or PCP) create their own flow. PC pumps are actually more efficient as viscosity increases and will have approximately the same flow rate regardless of the weight of the pumped material. That’s why the progressive cavity pump is a good choice for pumping heavy or viscous fluids.

2. Pumping shear-sensitive materials

First of all, please be aware that the volumetric flow rate of a Progressive Cavity pump is proportional to its rotation rate. Based on this, the pumping movement applies very little shear to the pumped fluid. Then, along with a lower internal velocity, It makes PC pumps ideal for pumping shear-sensitive materials. For example, some fluids containing fragile solids are just such shear-sensitive materials.

3. Pumping, dosing, and metering chemicals

It’s known that there are conveying cavities between the hollow stator and the helical rotor while the rotor turns and contacts the internal surface of the stator. In addition, the cavities inside a single progressive cavity pump taper at their ends and overlap, so there is no flow pulsing other than that caused by compression of the pump components or fluid.

It is just this smooth, low-pulsation pumping that makes progressive cavity pumps so well-suited for metering applications. As mentioned above, the flow rate of PC pumps is proportional to their speed, so they can be applied to doses of highly viscous fluids such as some additives and chemicals.

4. Pumping materials that contain abrasive particles

In other pump designs, fluids travel around the inside walls of the casing at a high speed. When the pumped material contains abrasive solids, this “scours” the pump’s surfaces and causes it to wear out before the end of its useful lifespan.

On the other hand, a progressive cavity pump takes the fluid through a long casing. The abrasive particles travel parallel to the internal surfaces at a slower speed instead of being hit centrifugally at a high speed. In this condition, PC pumps are far more abrasion-resistant and last much longer than other types of pumps when used for these specific applications. This is the answer to why PC pumps are well suited for pumping materials that contain abrasive particles.

5. Pumping fluids in applications that require varied flow rates

PC pumps produce a precise flow per revolution. This makes it easy to manage the pump flow by simply regulating the pump speed. They can also pair well with variable frequency drives for managing flow rates. Likewise, PC pumps can be used when you need to control a steady flow, but please be aware that the viscosity of the pumped fluid is variable. With such an advantage, why don’t you use PC pumps to pump fluids in applications that require varied flow rates?

What industries does Progressive Cavity Pump apply to?

Progressive cavity pumps (PC pumps) are variously applied in many different industries. From the wastewater treatment industry to the oil or food and beverages industries. PC pumps are well suited to solids, fluids with low to high viscosity, abrasive, and toxic or corrosive media. Some typical industries and specific applications that PC pumps are applied to are listed below FYI.

Biogas/Anaerobic Digestion Industry

• Pump the liquid livestock to collection tanks or animal waste directly to digesters
• Inject the liquid manure from liquid sewage collection tanks to digestate feed pump
• Pump the partially fermented biomass from the main digesters to post-digesters
• Transfer the digestate from the post-digesters to final storage & processing.

Brewing, Distilling & Oenological Industries

• Pump the crushed and destemmed must
• Transfer the must from fermenters to processing tanks
• Transfer the processed fluids to barrels for aging
• Convey the filtered product to bottling lines

Papermaking

• Transfer the pulps to the dosing/metering system
• Transfer the dyes, fillers & fixatives to the metering system
• Transfer the wastewater from forming stages (pressing, filtering, bleaching & coating) to the purification/treatment system.

Wastewater Treatment

• Transfer the thickened sludge from storage tanks to dewatering systems
• Transfer the treated sludge to storage silos, tanks or vats
• Dose and meter polymers & additives

Can progressive cavity pumps pump water?

The progressive cavity pump (PC Pump) is a positive displacement pump. It is a highly versatile pump that can be used in many different pumping applications.

PC Pump offers all the advantages of a positive displacement pump but it is different from a centrifugal pump and less commonly used. when pumping water-like fluids with low viscosity and when a fixed flow and constant discharge pressure are the basis of the application, a centrifugal pump is a good, economical choice instead of the progressive cavity pump. A well-applied centrifugal pump will offer many years of reliable service in simple pumping applications.

Thanks for reading this post! We are a reliable supplier of after-market spare parts for single progressive cavity pumps. Mainly provide the replacement universal parts for NETZSCH PUMPS, MONO PUMPS, SEEPEX PUMPS and ALLWEILER Pumps. The generic parts we supplied can highly match the original pump parts and be with equivalent service life. They are high-quality replacement PC Pump parts. Should you still have further questions on the single progressive cavity pumps or PC pump parts, please feel free to EMAIL US or WhatsApp us for further suggestions or recommendations.