Eccentric Screw Pumps - Gentle and pressure-stable conveyance for highly viscous, solids-laden, and challenging fluids
Eccentric screw pumps are designed as rotary positive-displacement pumps in which an eccentrically rotating rotor forms progressive pumping chambers within an elastomeric stator. This principle enables uniform, relatively low-pulsation pumping even with highly viscous, solids-laden, shear-sensitive, or gas-containing media.
At Harton Anlagentechnik GmbH, we consistently design eccentric screw pumps based on the medium, solids content, abrasiveness, temperature, gas content, speed range, and dry-run protection. This results in robust solutions for water and wastewater treatment, the process industry, the chemical industry, biogas, food applications in hygienic designs, as well as numerous metering and pumping tasks involving challenging media.
At Harton Anlagentechnik GmbH, we consistently design eccentric screw pumps based on the medium, solids content, abrasiveness, temperature, gas content, speed range, and dry-run protection. This results in robust solutions for water and wastewater treatment, the process industry, the chemical industry, biogas, food applications in hygienic designs, as well as numerous metering and pumping tasks involving challenging media.
Why Choose Eccentric Screw Pumps from Harton Anlagentechnik GmbH?
Eccentric screw pumps deliver a flow rate that is largely pressure-stable and volumetrically defined, and can be used even in applications where centrifugal pumps reach their limits due to high viscosity or media containing solids.
Our systems are suitable for high-viscosity slurries, paste-like media, suspensions, polymer solutions, and abrasive process wastewater; due to their design, they are also suitable for shear-sensitive products, provided that the speed, pressure level, and elastomer pairing are properly selected.
We offer 10 different models. Depending on the conveying application, the design is classified as:
In this process, maintenance access, shaft seals, installation space, solids inlet, and operating standards are specifically taken into account.
- Standard PCP
- Hopper pump
- Metering eccentric screw pump
- High-pressure PCP
- Hygienic design
- Mobile unit
- Modular design
- Bearing carrier design
- Articulated shaft/cardan design
- Long-coupled design
In this process, maintenance access, shaft seals, installation space, solids inlet, and operating standards are specifically taken into account.
Progressive cavity pumps are the preferred choice for applications where highly viscous, abrasive, solids-laden, or sensitive fluids must be conveyed reliably.
Typical applications:
- Conveyance of Slurries and Suspensions
- Dosing of polymer and chemical solutions
- Feeding of pasty or viscous media
- Transfer of substrates and biogas media
- Hygienic conveyance in food and process applications
- Mobile discharge and conveyance tasks
- Hopper pump applications for poor-flowing media
Typical industries:
- Water and Wastewater Technology
- Chemistry
- Food Processing (Hygienic Design)
- Mining
- Paper Industry
- Biogas and Substrates
- OEM dosing modules
Our in-house engineers evaluate not only the fluid and flow rate, but also sedimentation, gas content, abrasiveness, inlet conditions, and the expected stator service life.
We use the following parameters as a reliable technical framework, provided that no exact operating data is yet available for the project:
Volume flow rate Q:
0.05 to 1,500 m³/h
Typical range of applications for dosing and process applications:
0.5 to 250 m³/h
Differential pressure Δp:
1 to 80 bar
Typical step pressure:
Approx. 6 bar per stator/rotor stage; higher depending on the project
Media temperature:
-20 °C to +300 °C; in practice, this range is usually limited by the elastomer used
Typical recommended range for standard elastomers:
-10 °C to +120 °C
Ambient temperature:
-20 °C to +60 °C
Viscosity:
1 to 1,000,000 mPa·s
Typical economic sector:
100 to 300,000 mPa·s
Solid content:
0 to 80% by weight
Particle size:
0 to 150 mm, depending on the inlet, hopper, and geometry
Gas content in the medium:
0 to 95 vol.%
Speed range:
10 to 600 1/min
Typical range optimized for service life:
50 to 350 rpm
Self-priming head:
0 to 8 m
Dosing accuracy:
typically ±1 to ±3%
A key factor in service life is that eccentric screw pumps consist of a tribological pair formed by the rotor and stator. For this reason, temperature, dry-running events, abrasiveness, elastomer swelling, and the speed range are evaluated with particular care.
If not all values are available in advance, we use reasonable reference values for the initial technical evaluation and then refine them based on the medium and operating conditions.
Media temperature:
5 °C to 80 °C
Density:
950 to 1,300 kg/m³, often higher for slurries and suspensions
Viscosity:
1,000 to 100,000 mPa·s as a common range of application for PCP
Airflow:
1 to 100 m³/h for many process applications
Differential pressure:
6 to 24 bar as the typical range for standard models
Solid content:
5 to 40% by weight for slurries and suspensions
Particle size d50:
1 to 10 mm
Max. particle size:
20 to 50 mm, depending on the hopper and inlet
Gas content:
0 to 20% by volume; significantly higher concentrations are possible depending on the project
Suction height:
1 to 4 m for non-flooded installations
Company Profile:
continuous or intermittent
Departures per hour:
typically 1 to 12
Dry running:
not permitted
Safety Plan:
Dry-run protection via sensors and automatic shutdown is strongly recommended
Regulation:
Frequency Converter
Typical speed range:
80 to 250 rpm
ATEX:
Zone 1 or 2 is possible
Connection sizes:
Typically DN 25 to DN 150; larger sizes available depending on the project
These parameters serve as a reliable starting point for preparing a quote when the final operating point is still being determined.
Media and Process Materials
Depending on the medium, the leakage target is set to be minimized or defined as permissible. The shaft seal is adapted to the pressure, temperature, solids content, and chemistry.
Typical sealing concepts:
Safety-related standards:
Typical initial technical approaches:
Typical sealing concepts:
- single mechanical seal
- double mechanical seal
- Stuffing box for suitable applications
Safety-related standards:
- Overpressure protection is mandatory on the system side
- Dry-run protection as a mandatory feature
- Temperature limitation on the stator
- Speed limitation to optimize service life
- Leakage monitoring for critical media
- Measurement and flushing connections
- ATEX-compliant design as needed
Typical initial technical approaches:
- Dry running permitted: no
- Dry-run protection: Temperature or power monitoring with shutdown
- Leakage target: minimized
- Shut-off or flushing system: often required for abrasive, crystallizing, or polymerizing media
Materials, Durability, and Tribological Design
The choice of material is based on corrosion resistance, abrasion resistance, compatibility with elastomers, and temperature behavior.
Typical rotor materials:
Typical stator materials:
Typical sealing materials:
For abrasive applications, we define a wear management strategy involving rotor coating, reduced rotational speed, optimized inlet geometry, and specified replacement intervals. For corrosive media, 1.4404, 1.4571, or special materials are used.
Typical rotor materials:
- Stainless steel 1.4404
- Stainless steel 1.4571
- Hard-chromed version
- Ceramic or wear-resistant coated surfaces
Typical stator materials:
- NBR for oil-containing and many standard applications
- EPDM for aqueous and certain chemical media
- FKM for increased chemical and thermal requirements
- Specialty elastomers for project-specific load conditions
Typical sealing materials:
- FKM
- EPDM
- PTFE
- FFKM
- Typical hygienic surface requirement:
- Ra ≤ 0.8 µm in hygienic designs; even finer depending on the project
For abrasive applications, we define a wear management strategy involving rotor coating, reduced rotational speed, optimized inlet geometry, and specified replacement intervals. For corrosive media, 1.4404, 1.4571, or special materials are used.
Seals, Interfaces, and Safety
Depending on the medium, the leakage target is set to be minimized or defined as permissible. The shaft seal is adapted to the pressure, temperature, solids content, and chemistry.
Typical sealing concepts:
Safety-related standards:
Typical initial technical approaches:
Typical sealing concepts:
- single mechanical seal
- double mechanical seal
- Stuffing box for suitable applications
Safety-related standards:
- Overpressure protection is mandatory on the system side
- Dry-run protection as a mandatory feature
- Temperature limitation on the stator
- Speed limitation to optimize service life
- Leakage monitoring for critical media
- Measurement and flushing connections
- ATEX-compliant design as needed
Typical initial technical approaches:
- Dry running permitted: no
- Dry-run protection: Temperature or power monitoring with shutdown
- Leakage target: minimized
- Shut-off or flushing system: often required for abrasive, crystallizing, or polymerizing media
Drives, Control, and Energy
Eccentric screw pumps are typically equipped with an electric motor and a gearbox, since high torque is required at low speeds.
Typical initial technical approaches:
From a technical standpoint, flow rate control via a variable frequency drive is generally preferable, as it directly influences service life, shear, and energy input. Cold start capability is evaluated based on the medium, temperature, and torque reserve.
Typical initial technical approaches:
- Drive power: 1.5 to 45 kW for standard applications; higher for project-specific requirements
- Torque reserve: 20 to 40% above rated requirement
- Control: Frequency converters preferred
- Speed range: 50 to 350 rpm
- Operating hours per year: 2,000 to 8,000 h/a
- ATEX: Zones 1 and 2 possible
From a technical standpoint, flow rate control via a variable frequency drive is generally preferable, as it directly influences service life, shear, and energy input. Cold start capability is evaluated based on the medium, temperature, and torque reserve.
Connections, Installation, and Peripherals
The installation configuration significantly affects pumping performance, inlet behavior, and maintenance access.
Typical initial technical approaches:
For abrasive slurries, an inlet design that prevents sedimentation and maintains a defined inlet pressure is particularly important. For highly viscous media, a heating jacket or insulation may be required to prevent cold start problems and excessive torque.
Typical initial technical approaches:
- Connection sizes: DN 25 to DN 200
- Pressure ratings: PN 10 to PN 40
- Installation orientation: horizontal or slightly inclined; for hopper pumps, process-dependent
- Heated: optional, especially for high-viscosity media
- Peripheral equipment: hopper, screw conveyor, agitator, safety valve, bypass, flushing system
- Mobile version: with trolley, drip tray, and quick-connect couplings
For abrasive slurries, an inlet design that prevents sedimentation and maintains a defined inlet pressure is particularly important. For highly viscous media, a heating jacket or insulation may be required to prevent cold start problems and excessive torque.
Monitoring, Protective Functions, and Operational Safety
Dry running is one of the most critical failure mechanisms in eccentric screw pumps because it can quickly cause thermal and mechanical damage to the stator.
Typical protection and monitoring functions:
Customer request or recommendation for a SIL-/HAZOP-compliant design
This enables early detection and cost-effective control of dry running, abrasion, sedimentation, gas content, cold starts, and overloads.
Typical protection and monitoring functions:
- Dry-run protection
- Stator temperature monitoring
- Pressure monitoring
- Current and power monitoring
- Leakage monitoring
- Alarm and shutdown logic in accordance with plant standards
- Dry-run protection: required
- Availability: ≥ 95% as the standard target value
- Alarm/shutdown logic: both
Customer request or recommendation for a SIL-/HAZOP-compliant design
This enables early detection and cost-effective control of dry running, abrasion, sedimentation, gas content, cold starts, and overloads.
Quality, Testing, and Documentation
The scope of the audit is tailored to the project's criticality, the operator's standards, and the medium.
Typical audit scope:
Typical documents:
Details are generally provided in accordance with the agreement and the customer’s specifications.
Typical audit scope:
- Functional test
- Performance test for Q/Δp
- Leak test
- Pressure test, if required
- Material certificates in accordance with EN 10204 2.2 or 3.1
- Traceability via serial number and component assignment
Typical documents:
- Data sheet
- General arrangement or connection diagram
- Spare parts list
- Operating instructions
- Conformity Documentation
- Ex Certification for ATEX Applications
Details are generally provided in accordance with the agreement and the customer’s specifications.
Service, Maintenance, and Operating Costs (TCO)
For eccentric screw pumps, operating costs are significantly influenced by stator service life, rotor wear, speed range, and dry-running events.
Key TCO drivers:
Typical wear parts:
For critical applications, standby, 1+1, or quick-change concepts may be appropriate. Training on stator/rotor replacement, venting, dry-run prevention, and troubleshooting is tailored to each specific project.
Key TCO drivers:
- Energy consumption
- Stator consumption
- Downtime
- Service costs
- Media losses
Typical wear parts:
- Stator
- Rotor
- Joint components
- Seals
- Bearings, if applicable
For critical applications, standby, 1+1, or quick-change concepts may be appropriate. Training on stator/rotor replacement, venting, dry-run prevention, and troubleshooting is tailored to each specific project.
Advantages of Harton's Eccentric Screw Pumps
- Consistent flow rate even with high viscosity
- Suitable for media containing solids, abrasive media, and shear-sensitive media
- Wide variety of designs with 10 different models
- High dosing accuracy within the appropriate operating window
- Flexible inlet and hopper designs
- Customizable rotor/stator and sealing system
- Technical design by experienced in-house specialists
- ATEX Zones 1 and 2 supported; see ATEX checklist
Types and Variants of Eccentric Screw Pumps
Eccentric screw pumps for various applications
We offer eccentric screw pumps in various designs to optimally accommodate a wide range of pumped media and applications. Whether you’re dealing with abrasive substances, hygienically demanding processes, self-priming applications, or universal standard solutions—we’ll help you select the right eccentric screw pump. In doing so, we take into account the properties of the fluid being pumped as well as requirements regarding viscosity, temperature, flow rate, and industry-specific standards.
Eccentric screw pumps for abrasive media
For abrasive media, the design of the eccentric screw pump is adapted with reinforced components such as wear-resistant seals and rotors made of highly durable materials like hard cast iron or ceramics. These pumps are ideal for handling slurries, cement, and other abrasive substances.
| Pressure | up to 30 bar |
| Accuracy | ±1 - 3 % |
| Media | abrasive, oily liquids |
| Viscosity | 5.000 - 1.000.000 mPa·s |
| Temperature | -20 to +150 °C |
| Materials | Duplex, Hard cast iron |
| ATEX | optional |
| Dosing capacity | 0,1 - 1.500 l/h |
Sanitary Eccentric Screw Pumps
Hygienic progressive cavity pumps meet the strict requirements of the food and pharmaceutical industries. They ensure hygienic pumping processes that comply with current standards such as FDA and EHEDG. These pumps are CIP- and SIP-capable, enabling thorough cleaning after operation.
| Dosing capacity | 0,1 - 1.500 l/h |
| Pressure | up to 6 bar |
| Accuracy | ±0,5 - 2 % |
| Media | Food, Pharmaceuticals |
| Viscosity | 1 - 100.000 mPa·s |
| Temperature | 0 to 150 °C |
| Materials | Stainless Steel 1.4404 |
| ATEX | optional |
Self-priming eccentric screw pumps
Self-priming eccentric screw pumps offer the advantage of being able to operate even under low-suction or flooded suction conditions. They are particularly well-suited for applications that require a continuous supply, such as water or wastewater treatment.
| Media | Water, Wastewater, Industrial Waste |
| Viscosity | 1 - 100.000 mPa·s |
| Temperature | -10 to +100 °C |
| Materials | Stainless steel, Cast iron |
| ATEX | optional |
| Dosing capacity | 0,5 - 2.000 l/h |
| Pressure | up to 10 bar |
| Accuracy | ±0,5 - 3 % |
Standard Eccentric Screw Pumps
Eccentric screw pumps provide precise, pulsation-free transfer of viscous and abrasive fluids. The eccentric rotor moves through the stator housing, conveying the fluid without mechanical disturbance. These pumps are frequently used in wastewater treatment, the food industry, and the chemical and pharmaceutical industries.
| Materials | Stainless steel, Cast iron |
| ATEX | optional |
| Dosing capacity | 0,1 - 2.000 l/h |
| Pressure | up to 10 bar |
| Accuracy | ±0,5 - 3 % |
| Media | viscous liquids, solid particles |
| Viscosity | 1 - 200.000 mPa·s |
| Temperature | -20 to +150 °C |
Relevance for Engineers and Technical Buyers
For a cost-effective design that maximizes service life, the following factors are particularly crucial: flow rate, differential pressure, viscosity, solid and gas content, fluid temperature, speed range, and the selection of the appropriate rotor/stator pairing and dry-run protection.
When procuring equipment, in addition to flow rate, operating pressure, and materials, connection sizes, sealing systems, elastomer quality, ATEX requirements, variable-frequency drive operation, and maintenance and operating standards should also be clearly defined.
Depending on the application, requirements such as ATEX compliance, hygienic designs for food applications, and project-specific material, pressure, and functional tests must be taken into account as part of the technical specifications.
FAQs by Industry
Select an industry
Eccentric screw pumps in water and wastewater treatment: Sludge treatment
Eccentric Screw Pumps in the Food Industry: Hygienic Conveyance
Eccentric Screw Pumps in the Chemical Industry: Polymer and Raw Material Handling
Eccentric screw pumps in the oil and gas industry: drilling mud and crude oil
Eccentric screw pumps in the paint and coatings industry: Pigment handling
Eccentric screw pumps in the construction and mining industries: Concrete and mortar conveyance
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