The progressive cavity pump is a special positive displacement pump used for precise metering of liquids or viscous materials. It consists of a helical rotor (the eccentric shaft) that rotates in an eccentric position within an elastic stator. The rotational motion of the rotor creates a cavity that moves the material being pumped from the inlet side to the outlet side. The progressive cavity pump features high accuracy, repeatability and the ability to efficiently convey viscous materials. It is used in various industries where precise metering is required for production processes and applications.
A progressive cavity pump in metering technology works on the basis of a helical rotor rotating in an elastic stator. This design creates a tapered cavity between the rotor and the stator that transports the material being pumped from the inlet side to the outlet side. Here is a step-by-step explanation of how a progressive cavity pump works in metering applications:
Inlet phase: at the beginning of the pumping cycle, the helical rotor is eccentric (offset) within the elastic stator. The cavity between the rotor and stator is wide open at the inlet. The material to be pumped, whether a liquid or viscous material, is drawn into the cavity as the rotor turns and increases the space.
Metering Phase: As the rotor continues to rotate, it shifts along the longitudinal axis of the stator. This gradually narrows the cavity between the rotor and stator. The material is forced through this constriction and moved towards the outlet.
Conveying phase: As the rotor continues to move along the stator, the material is continuously pressed between the rotor and the stator. The pressure in the cavity increases and the material is expelled from the pump through the outlet.
Repeat: This cycle of inlet, metering, delivery, and discharge is repeated continuously as the rotor continues to rotate. In this way, the material to be conveyed is precisely metered and delivered in predefined quantities.
The key aspect of progressive cavity pumps is the displacement action of the rotor in the stator, which allows materials to be metered with high accuracy and repeatability. The speed of the rotational motion can be controlled to adjust the flow rate and metering according to the requirements of the application.
Progressive cavity pumps are particularly well suited for conveying viscous and abrasive materials and are used in many industries for precise metering and conveying, including food processing, chemical, pharmaceutical, wastewater treatment and more.
Progressive cavity pumps offer numerous advantages in various applications due to their special design and mode of operation. Here are some of the main advantages of progressive cavity pumps:
High metering accuracy: progressive cavity pumps are known for their exceptionally high metering accuracy. They can provide precise and repeatable metering of liquids or viscous materials.
Conveying materials of varying viscosity: They are capable of efficiently conveying low- to high-viscosity materials, including those that are more difficult for other types of pumps to handle.
Gentle material handling: progressive cavity pumps handle the material to be conveyed gently, as it is hardly subjected to shear forces during the conveying process. This is important to preserve sensitive or abrasive materials.
Self-priming: progressive cavity pumps are often self-priming and can draw liquids from low levels or against a slight vacuum.
Low pulsation: Compared to, for example, reciprocating pumps, progressive cavity pumps produce a low level of pulsation in the fluid flow, which is an advantage in applications involving sensitive instruments or equipment.
Conveying abrasive materials: They can convey abrasive or filled materials without major problems. Individual components are often available in hardened versions.
High reliability: progressive cavity pumps are generally reliable and require little maintenance. They have a long service life and are suitable for continuous operation.
Versatility: They can be used for a wide range of fluids and materials, including lubricants, adhesives, sealants and potting compounds.
Adaptability: progressive cavity pumps can be adapted for various applications and environments, including hygienic or explosion-proof requirements.
Efficiency: They are typically energy efficient and achieve high metering capacities with low energy consumption.
These benefits make progressive cavity pumps a popular choice in a variety of industries, including food processing, chemical, pharmaceutical, wastewater treatment, construction and many others where precise metering and pumping of viscous or sensitive materials is required.
Progressive cavity pumps can be divided into different types according to the design and application. Here are some of the main types of progressive cavity pumps:
There are two main versions. The first would be for transferring materials from drums.
The progressive cavity pump would be mounted directly on to a 20l or 200l follower plate and would be used to transfer the material directly from the 20l or 200l drum into a metering system.
The second version would be for accurately metering materials.
Meter Mix is focussing on precise metering of small volumes of material at the mixing head.
Progressive cavity pumps are used in a variety of industries and applications, especially where precise metering and transfer of viscous or sensitive materials is required. Here are some typical applications of progressive cavity pumps:
Automotive industry: they are used to meter lubricants, adhesives or sealants onto automotive components.
Electronics: They are suitable for potting components where particularly small quantities are required.
The versatility and precision of progressive cavity pumps make them a popular choice in a wide range of industries and applications where metering and material handling are critical. They are particularly well suited to gently handle viscous or abrasive materials while maintaining high metering accuracy.