A Progressive Cavity Pump is a type of positive displacement pump with a rotor rotating within a housing called a stator. The rotor is always metallic, and the stator is made of rubber. It looks somewhat like a screw thread – the fluid is between the cavities, and the rotary motion of the rotor forces the liquid through from one end to the other.
When a product needs to be handled gently and is used in all sectors of industries to convey almost all types of media continuously and smoothly, with low pulsation and dosing in proportion to speed, we can use progressing Cavity pumps are used. They are used for dosing applications requiring accuracy (multi-stage pumps). Their range covers most miniature dosing pumps with a few ml flow rates to high-performance pumps that pump up to 1000 m³/h.
One of the main advantages of a progressive cavity pump is that it is easy to regulate the flow of product simply by controlling the speed of the pump.
What fluids and applications is a progressing cavity pump suitable for?
A progressing cavity pump excels when handling highly viscous fluids that must be moved long distances (discharge pressure up to 48 bar). Typical fluids may include slurry, mashes, pulps, and dough from wastewater treatment plants, anaerobic digestion facilities, and paper recycling plants. As the pump flow rate is proportional to the speed, the pump can be used to dose viscous fluids such as additives and chemicals. Models are available for dosing-type applications, hygienic environments, and drum-emptying.
Progressive cavity pumps are fundamentally fixed flow rates pumps, like piston pumps and peristaltic pumps. This type of pump needs a fundamentally different understanding than the types of pumps to which people are more commonly introduced, namely ones that can be thought of as generating pressure. This can lead to the mistaken assumption that all pumps can adjust their flow rates by using a valve attached to their outlet. Still, with this type of pump, this assumption is a problem since such a valve will have practically no effect on the flow rate. Ultimately, closing it will involve very high pressure being generated. To prevent this, pumps are often fitted with cut-off pressure switches, rupture discs (deliberately weak and easily replaced), or bypass pipes that allow a variable amount of fluid to return to the inlet. With a bypass fitted, a fixed flow rate pump is effectively converted to a set pressure one.
At the points where the rotor touches the stator, the surfaces generally travel transversely, so small areas of sliding contact occurs. These areas need to be lubricated by the fluid being pumped (hydrodynamic lubrication). This can mean that more torque is required for starting, and if allowed to operate without fluid, called ‘run dry,’ rapid deterioration of the stator can result.
While progressive cavity pumps offer long life and reliable service transporting thick or lumpy fluids, abrasive fluids will significantly shorten the life of the stator. However, slurries (particulates in a medium) can be pumped reliably if the medium is dense enough to maintain a lubrication layer around the particles and protect the stator.
Structure and composition
The pump has a spare stator integrated with the original sub, which can be used after a simple u-turn installation. Flexible coupling rod without wear and maintenance, fast clamping stator system, loosen the discharge body of the connecting bolt; you can remove the cover plate and replace it without moving any other parts of the pump; pump cover plate is also the pump information nameplate, with detailed operation instructions and maintenance instructions and additional information Standard shaft plug-in reduction motor, compact and rugged, is directly connected to the pump through a hollow shaft.
Scope of application:
· Petroleum industry: heavy oil transportation, oil, and gas mixed transportation, oil-water separation, waste oil recovery systems, etc.
· Chemical and pharmaceutical: various pastes, emulsions, suspensions, etc.
· Environmental engineering: transportation of various sewage, dewatered sludge, metering and dosing of flocculants and their chemical preparations, etc.
· Mineral engineering: production equipment for titanium dioxide, kaolin, calcium carbonate, etc.
· Food industry: dairy products, fruit juice, puree, vegetable sauce, beer, etc.
· Paper industry: raw material equipment, pulping and wastewater treatment, etc.
Advantage comparison with other pumps
· Compared with the centrifugal pump, the single screw pump does not need to install valves, and the flow is a stable linear.
·Compared with pneumatic diaphragm pumps, single screw pumps can transport various mixed impurities containing gas and solid particles or fibers and can also transport various corrosive substances.
· Compared with gear pumps, single screw pumps can deliver high-viscosity substances.
· Unlike plunger pumps, diaphragm pumps, and gear pumps, screw pumps can be used for pharmaceutical filling and metering.
Here are some common questions and answers about Progressive Cavity Pumps (PCPs), which are commonly used in the oil and gas, chemical, and food industries:
Q: What is a Progressive Cavity Pump? A: A Progressive Cavity Pump is a type of positive displacement pump that uses a single helical rotor and a stator with a double helix geometry to move fluid through the pump. As the rotor turns, it creates a series of cavities that trap and move fluid from the inlet to the outlet of the pump.
Q: What are the advantages of using a Progressive Cavity Pump? A: PCPs offer several advantages, including the ability to handle viscous and abrasive fluids, low shear pumping, and a wide range of flow rates and pressures. They are also self-priming, have low pulsation, and can handle solids without clogging.
Q: What materials are Progressive Cavity Pumps made of? A: PCPs can be made from a variety of materials, including stainless steel, cast iron, and specialty alloys. The materials used depend on the application and the fluid being pumped.
Q: What are some well-known Progressive Cavity Pump brands? A: Some well-known PCP brands include Netzsch, Moyno, and NEMO. These brands are known for their high-quality pumps and long-lasting performance.
Q: How do I select the right Progressive Cavity Pump for my application? A: To select the right PCP, you should consider factors such as the type of fluid being pumped, the flow rate and pressure requirements, and the operating conditions (e.g., temperature, viscosity, and solids content). Consulting with a pump specialist can also be helpful in selecting the appropriate pump.
Q: How do I maintain and repair a Progressive Cavity Pump? A: Regular maintenance is essential for prolonging the life of a PCP. This includes inspecting and replacing the rotor and stator when necessary, checking and replacing seals and bearings, and ensuring the pump is properly lubricated. If repairs are needed, replacement parts can be purchased from the pump manufacturer or a third-party supplier.
Q: What are some common problems with Progressive Cavity Pumps? A: Common problems with PCPs include wear and damage to the rotor and stator, leakage around the seals, and clogging due to solids buildup. Proper maintenance and material selection can help minimize these issues.
In conclusion, Progressive Cavity Pumps are versatile and reliable pumps that are widely used in various industries. Selecting the appropriate pump, regular maintenance, and proper repairs can help ensure efficient and reliable pump operation. Well-known brands such as Netzsch, Moyno, and NEMO are known for their high-quality PCPs and are worth considering for your pumping needs.