Positive Displacement Pumps
Dynapumps offer a wide range of Positive Displacement Pumps including Air Operated Diaphragm pumps, Gear pumps, Metering Piston pumps, Peristaltic pumps, Progressive Cavity pumps, Pulse-Less Metering pumps, Vane pumps from leading pump manufacturers such as WANNER Hydra-Cell, Argal, SEEPEX, Graco and others.
¦ Positive Displacement Pump Selection Guid
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Pump Type
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Primary Mechanical Action
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Max Pressure Capacity
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Best Suited Applications
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Distinctive Advantage
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Progressive Cavity / Helical Rotor
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Helical rotor rotating inside a double-helix elastomer stator
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Mid to High
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Thick slurries, sludge dewatering, and polymer dosing
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Continuous, low-pulsation flow for high-solids media
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Rotary Lobe (API 676)
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Two non-contacting, synchronized lobes rotating in a chamber
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Low to Mid
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Food processing, pharmaceuticals, oil transfer, and sewage
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Extremely low shear, gentle handling of delicate media
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Air-Operated Diaphragm (AOD)
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Reciprocating flexible diaphragms driven by compressed air
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Low
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Volatile chemical transfer, portable sumps, and hazardous fluids
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Dry self-priming, intrinsically safe running, and run-dry capabilities
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Multi-Screw Pumps (2, 3, 4, 5 Screw)
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Intermeshing parallel screws moving fluid axially
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Mid to High
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High-capacity oil transfer, multiphase well fluids, and lubricants
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Very smooth, non-pulsating flow at large industrial volume rates
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Piston / Plunger Pumps
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Reciprocating piston changing internal chamber displacement
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Very High (up to 1,380 bar)
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High-pressure water spraying, mine flush systems, and boiler feeds
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Highest volumetric efficiency at extreme system backpressures
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¦ Frequently Asked Questions (FAQs)
- What makes positive displacement pumps different from centrifugal pumps?
Centrifugal pumps use high-speed impellers to impart kinetic energy, meaning flow rates drop as pressure increases. Positive displacement pumps trap fluid within fixed chambers, forcing out a set volume per cycle. This produces constant flow rates regardless of system backpressure fluctuations.
- Can Dynapumps PD pumps run dry safely?
Certain configurations, such as Air Operated Diaphragm pumps or custom rotary lobe tanker-unloading packages, are engineered to run dry without causing damage to internal components. However, closely meshing steel designs (like gear pumps) generally count on the media for internal cooling and lubrication.
- How do you adjust the flow rate of a positive displacement pump?
Because PD pumps deliver a fixed volume per revolution or stroke, modifying flow rates is achieved by adjusting the operation speed using frequency inverters or Variable Speed Drives (VSDs).
- Are positive displacement pumps appropriate for abrasive materials?
Yes. Helical rotor (progressive cavity) and specialised rotary lobe designs feature wide clearance chambers or durable elastomer stators specifically manufactured to transfer high-solids mining tailings and abrasive waste slurries without causing premature rotor destruction.