1. Introduction to Screw Pumps in Low-Flow, High-Pressure Systems

A screw pump is a positive displacement pump that uses one or more intermeshing

screws to move fluid along the screw axis. In low-flow, high-pressure systems,

screw pumps are frequently chosen because they deliver:

• Stable and repeatable flow
• High discharge pressures
• Low pulsation and vibration
• Good efficiency over a wide viscosity range
• Long service life with proper lubrication

Low-flow, high-pressure systems appear in many industries:

lubrication circuits, hydrostatic bearing supply, fuel injection skids,

hydraulic power units, test benches, metering and dosing systems, and

pressure boosting for specialty fluids. These systems usually demand

precise flow at pressures that may reach hundreds of bar, often under

continuous duty.

1.1 What Is a Low-Flow, High-Pressure System?

There is no universal cutoff, but in many industrial contexts a

low-flow, high-pressure system can be characterized as:

• Flow rate: typically below 50 m3/h, and often below 10 m3/h
• Discharge pressure: above 20 bar, often reaching 80–250 bar or more
• Continuous or intermittent duty with tight control of process pressure

Such systems are used where the volume of fluid required is modest, but the

force needed to move or control that fluid is large. This is exactly the

operating window where screw pumps excel as low-flow,

high-pressure pumps.

1.2 Why Use Screw Pumps in This Operating Window?

Compared to centrifugal pumps, which are highly efficient at

medium-to-high flow and moderate pressure, screw pumps provide consistent

flow almost independent of pressure. This makes them well suited to:

• Small but precise flows of viscous or lubricating fluids
• Systems where pressure changes frequently but flow must remain stable
• Applications where low noise and low pulsation are important

As a positive displacement design, the screw pump delivers a fixed volume

of fluid per revolution. Pressure is generated by the resistance of the

system, up to the pump’s rated limit and the opening pressure of any

built-in or external relief valve.

2. Basic Operating Principle of Screw Pumps

Screw pumps are positive displacement pumps. They consist of one

or more helical screws rotating inside a closely fitting housing. As the screws rotate,

they trap pockets of fluid and move them continuously from the suction side to the discharge side.

2.1 Core Working Mechanism

The working principle can be summarized in three main steps:

1. Fluid Inlet: Fluid enters the pump at the suction port.
2. Axial Transport: As the screw(s) rotate, fluid is trapped in cavities

   formed between the screw profile and the pump casing and is carried axially along the shaft.

3. Discharge: Trapped fluid is delivered to the discharge port at a higher pressure.

Since the fluid is transported in sealed cavities with continuous motion, screw pumps achieve

very low pulsation and gentle handling, which is valuable in sensitive

low-flow, high-pressure applications.

2.2 Key Components

• Screws (Rotors): One, two, or three screws with a specific helix angle and pitch.

  The geometry determines displacement per revolution and pressure capability.

• Housing / Casing: Precision-machined to form close clearances that minimize internal leakage.
• Bearings: Radial and thrust bearings to carry rotor loads at high pressure.
• Seals: Mechanical seals or packing to prevent leakage at the shaft penetration.
• Drive: Electric motor, engine, or gear motor, often via flexible coupling.

2.3 Pressure Generation vs Flow Generation

The screw pump does not inherently “create” pressure; it generates flow.

The system resistance (valves, piping, process equipment) converts this

flow into pressure. In a low-flow, high-pressure system:

• The pump delivers nearly constant flow up to its mechanical and power limits.
• Discharge pressure rises with increasing system restriction.
• A relief valve is required to protect the pump and piping from overpressure.

3. Why Screw Pumps Are Ideal for Low-Flow, High-Pressure Applications

Screw pumps bring together several characteristics that align well with

low-flow, high-pressure operating requirements. The combination of

low pulsation, high-pressure capability, and efficiency makes them

a preferred technology in many demanding systems.

3.1 Stable Flow at Varying Pressure

Because screw pumps are positive displacement pumps, the flow rate is

primarily set by pump size and speed, not by system pressure. In

low-flow, high-pressure systems where pressure can change rapidly,

this stable flow characteristic simplifies control

and sizing of downstream components.

3.2 High Discharge Pressure Capability

Many screw pump designs can handle discharge pressures reaching

80–250 bar, and in certain specialized versions even higher,

depending on:

• Rotor geometry
• Casing and screw materials
• Clearances and sealing concept
• Fluid viscosity and lubricity

This capability is central to their use in hydraulic power units,

fuel injection skids, and other systems where low flow must be delivered

at very high pressure.

3.3 Low Pulsation and Noise

The continuous, overlapping cavities in screw pumps generate a very

smooth flow with minimal pulsation. Benefits in low-flow, high-pressure systems include:

• Reduced vibration in piping and components
• Lower acoustic noise levels
• More accurate performance of flow and pressure instrumentation
• Greater stability in control loops and servo systems

3.4 Wide Viscosity and Fluid Handling Range

Screw pumps can handle a broad range of viscosities, from light fuels

to heavy lubricating oils. Many low-flow, high-pressure systems involve:

• Hydraulic oil
• Lubricating oil
• Fuel oil and diesel
• Polymer melts (in specialized designs)

The positive displacement mechanism provides consistent

volumetric efficiency over this viscosity range, especially in well-lubricated services.

3.5 Self-Priming Capability

Most screw pumps are self-priming, which allows them to draw fluid

from a reservoir even if the suction line is initially empty. In

low-flow, high-pressure applications with intermittent duty, this

can eliminate the need for separate priming arrangements.

4. Types of Screw Pumps for High-Pressure Duty

Several screw pump configurations are used in low-flow, high-pressure systems.

The most common are single-screw pumps, twin-screw pumps,

and triple-screw (three-screw) pumps. Each type has specific

characteristics that affect pressure capability, flow range, and fluid compatibility.

4.1 Single-Screw (Progressive Cavity) Pumps

Single-screw pumps, often referred to as Progressive cavity pumps,

consist of a single helical rotor turning inside an elastomeric stator with a double helix cavity.

• Suited to: viscous, shear-sensitive, or solids-laden fluids
• Pressure capability: often up to 24 bar per stage, with multi-stage designs for higher pressures
• Flow range: from very low to medium flows

While not always the first choice for clean hydraulic oils, they are used in

specialized low-flow, high-pressure systems involving difficult fluids. In many

industrial lubrication and hydraulic applications, however, multi-screw metal pumps

are preferred for their compactness and lubrication-friendly design.

4.2 Twin-Screw Pumps

Twin-screw pumps use two intermeshing screws that rotate in opposite directions.

The screws can be timing gear driven so they do not contact each other,

enabling gentle handling and the ability to run dry for short periods.

• Suited to: multiphase fluids, low NPSH conditions, a wide viscosity range
• Pressure capability: widely ranges, often up to 80–160 bar in high-pressure designs
• Flow range: from low to very high flows, depending on frame size

In low-flow, high-pressure systems, twin-screw pumps are selected when:

• The fluid may entrain gas
• Dry-run capability is desirable
• A broad operating envelope is needed (variable flow with speed control)

4.3 Triple-Screw (Three-Screw) Pumps

Triple-screw pumps, or three-screw pumps, consist of one

driving screw (the power rotor) and two idler screws.

The driven screw transmits torque to the idlers through a hydrodynamic film of the pumped fluid.

• Suited to: clean, lubricating fluids such as hydraulic oil and lubricating oil
• Pressure capability: can exceed 100–250 bar depending on design
• Flow range: from very low flows (a few L/min) to medium flows

Three-screw pumps are widely used as low-flow, high-pressure screw pumps

in lubrication systems, hydraulic power systems, fuel oil skids, and similar applications.

Their compact design, high efficiency, and low pulsation make them particularly attractive.

4.4 Comparing Screw Pump Types for Low-Flow, High-Pressure Service

5. Key Performance Parameters in Low-Flow, High-Pressure Operation

For selecting and evaluating screw pumps in low-flow, high-pressure systems,

several performance parameters are especially important.

5.1 Flow Rate (Capacity)

Flow rate in screw pumps is mostly determined by:

• Displacement per revolution (rotor geometry)
• Rotational speed
• Volumetric efficiency (affected by clearances, viscosity, and pressure)

In low-flow, high-pressure configurations, flow is often in the range of:

• 0.1–10 m3/h for small lubrication and hydraulic units
• 10–50 m3/h in large industrial skids or centralized systems

5.2 Discharge Pressure

The maximum working pressure depends on pump size, materials, and application.

Designers should distinguish between:

• Continuous operating pressure (typical working limit)
• Maximum allowable pressure (short-term or relief valve setting)

In low-flow, high-pressure screw pump service, discharge pressures may range from:

• 20–80 bar for general hydraulic and lubrication systems
• 80–250 bar for high-pressure fuel, test, and injection systems

5.3 Volumetric and Overall Efficiency

Efficiency in screw pumps is influenced by:

• Internal leakage (slip) at high pressure
• Mechanical friction in bearings and seals
• Fluid viscosity and temperature

For well-designed screw pumps handling moderately viscous lubricating fluids:

• Volumetric efficiency can exceed 90% at design conditions
• Overall efficiency often lies in the 70–85% range

5.4 Net Positive Suction Head (NPSH)

At low flow and high pressure, the NPSH available (NPSHa) at the pump suction

may be limited by system layout or fluid properties (e.g., hot oil). Screw pumps generally have

favorable NPSH characteristics compared to many other positive displacement pumps. Nevertheless:

• Ensure NPSHa > NPSHr with adequate margin
• Use flooded suction whenever possible
• Minimize suction line losses and avoid unnecessary fittings

5.5 Pulsation, Noise, and Vibration

One of the main reasons screw pumps are chosen in low-flow, high-pressure applications is the

combination of:

• Very low pulsation in discharge flow
• Low noise compared to reciprocating pumps
• Reduced vibration in the mechanical structure

This improves system reliability, especially where sensitive instrumentation,

control valves, or servo mechanisms are used.

6. Typical Applications of Screw Pumps in Low-Flow, High-Pressure Systems

Screw pumps, particularly three-screw and twin-screw designs, are widely used in industries

that require reliable low-flow, high-pressure performance. Some representative applications

are outlined below.

6.1 Lubrication Systems

Many rotating machines, including turbines, compressors, and large gearboxes, use

forced lubrication systems. In these systems:

• Flow rates are relatively low compared to process flows
• Required pressures are moderate to high (e.g., 10–80 bar)
• Fluid is typically a clean lubricating oil with good viscosity

Screw pumps are ideal in this role because they provide stable, non-pulsating oil flow to bearings

and seals, minimizing dynamic loads and extending equipment life.

6.2 Hydraulic Power Units (HPUs)

Hydraulic power units convert mechanical energy into hydraulic energy in the form of

pressurized fluid. Screw pumps in these units:

• Supply low to moderate flows (e.g., 5–80 L/min)
• Generate high pressures (e.g., 80–250 bar or more)
• Operate continuously or on-demand with variable speed drives

Compared with gear pumps, screw pumps offer lower noise levels and smoother flow,

which is important for precision hydraulic actuators and servo systems.

6.3 Fuel Injection and Burner Systems

In fuel supply systems for burners, boilers, and engines, screw pumps are used

to deliver low-flow, high-pressure fuel oil or diesel:

• Precise metering at stable pressure is critical to combustion performance
• Fuel often serves as both working fluid and lubricant
• Pressures can reach 20–160 bar, depending on burner and injector design

Three-screw pumps are a standard choice in such systems because they are

compact, efficient, and handle light to medium viscosity fuels well.

6.4 Test Benches and Pressure Testing

Screw pumps are frequently used in test benches and

pressure testing rigs where low flow is required at

very high pressure, such as:

• Component pressure testing
• Valve calibration
• Hydraulic system functional tests

The combination of accurate flow control and smooth pressure buildup

helps protect sensitive test pieces and instrumentation.

6.5 High-Pressure Cooling and Seal Systems

Many process compressors, mechanical seals, and special bearings require

a flow of cooling or sealing fluid at elevated pressure but relatively low flow:

• Mechanical seal flush systems
• Jacket cooling systems
• High-pressure flushing for process equipment

Screw pumps reliably maintain these flows and pressures, improving

equipment reliability and process safety.

6.6 Metering and Dosing in Process Industries

In cases where the required flow is low and the operating pressure is high,

screw pumps can serve as metering or dosing pumps for:

• Additive injection
• Corrosion inhibitor dosing
• Polymer or resin injection at pressure

Speed control and accurate volumetric displacement help achieve precise dosing,

while the high-pressure capability ensures injection into pressurized systems.

7. Design and Material Considerations

Designing screw pumps for low-flow, high-pressure applications requires careful

attention to rotor geometry, clearances, materials, sealing arrangements, and

thermal effects. These factors have a direct impact on pump reliability and efficiency.

7.1 Rotor and Housing Geometry

The geometry of the screws and housing determines:

• Displacement per revolution (and thus flow at a given speed)
• Number of cavities in contact at any time (affecting pulsation)
• Ability to handle high-pressure gradients without excessive leakage

In low-flow, high-pressure designs, rotors often have:

• Optimized pitch and diameter to balance displacement against pressure loads
• High precision machining to maintain tight clearances
• Surface finishes that promote hydrodynamic lubrication

7.2 Materials of Construction

Typical materials for screw pumps in high-pressure applications include:

• Carbon steel or alloy steel casings for strength and pressure containment
• Hardened steel or alloy rotors for wear resistance
• Stainless steels for corrosion resistance with aggressive fluids
• Special coatings where additional wear or corrosion protection is needed

Material selection must consider:

• Fluid chemistry and temperature
• Required design pressure and safety factors
• Compatibility with seals and gaskets

7.3 Sealing Arrangements

High-pressure operation requires robust sealing of the drive shaft:

• Mechanical seals are common in high-pressure, clean-fluid applications.
• Cartridge seal designs simplify installation and replacement.
• Balanced seal designs help manage high-pressure differential across the seal faces.

In some lubrication systems, the fluid itself serves as seal flush and cooling medium, improving

seal life and reliability.

7.4 Bearings and Load Management

At high pressures, axial hydraulic forces act on the screws. Bearing design must:

• Carry axial and radial loads safely
• Minimize frictional losses
• Operate reliably in the pumped fluid, which often doubles as bearing lubricant

Thrust balancing arrangements, such as hydraulic balancing pistons or opposed rotor designs, may

be used to limit bearing load and increase service life.

7.5 Thermal Considerations

In low-flow, high-pressure screw pumps, power input and pressure drop can generate heat:

• Fluid temperature rise can affect viscosity and efficiency.
• Thermal expansion of components influences operating clearances.
• Seal and bearing materials must withstand operating temperatures.

Designs may incorporate cooling arrangements, such as:

• Cooling jackets
• External coolers in the circuit
• Temperature monitoring and control

8. Advantages of Screw Pumps vs Other Pump Technologies

In low-flow, high-pressure systems, engineers can choose among screw pumps,

gear pumps, piston/plunger pumps, vane pumps, and others. Screw pumps offer

a set of advantages that often make them the preferred option.

8.1 Screw Pumps vs Gear Pumps

Both screw pumps and gear pumps are positive displacement designs commonly

used for oils. However, in low-flow, high-pressure applications:

• Smoothness: Screw pumps provide smoother, less pulsating flow.
• Noise: Screw pumps are typically quieter due to continuous meshing and hydrodynamic lubrication.
• Pressure capability: High-pressure screw pump designs may exceed the economic limits of many gear pumps.
• Efficiency at higher viscosities: Screw pumps often maintain higher volumetric efficiency.

8.2 Screw Pumps vs Piston and Plunger Pumps

Reciprocating piston and plunger pumps are also capable of very high pressure at low flow.

Compared to these pumps, screw pumps offer:

• Low pulsation: Screw pumps deliver a nearly continuous flow, whereas reciprocating pumps need pulsation dampeners.
• Lower vibration and noise: Rotary motion is inherently quieter than reciprocating motion.
• Simplified piping: Less need for pulsation-control equipment.

However, piston and plunger pumps may still be preferred when:

• Extremely high pressures (hundreds to thousands of bar) are needed.
• Fluid is non-lubricating or contains solids that screw pumps cannot handle.

8.3 Screw Pumps vs Vane Pumps

Vane pumps are used in many hydraulic systems, but screw pumps have particular strengths:

• Higher efficiency with viscous lubricating oils
• Better suitability for continuous duty at high pressure
• Lower noise and smoother flow in many cases

For small compact systems with moderate pressure, vane pumps may compete; for robust

low-flow, high-pressure duty, screw pumps often offer longer life and better performance.

9. Selection Guidelines for Low-Flow, High-Pressure Screw Pumps

Proper pump selection is crucial to achieve reliability and efficiency.

Below are general guidelines for selecting screw pumps in low-flow, high-pressure applications.

9.1 Define System Requirements

Start by accurately defining:

• Required flow range (minimum, normal, maximum)
• Required discharge pressure (operating and maximum)
• Fluid properties: viscosity, temperature, density, lubricity, solids content
• Duty cycle: continuous, intermittent, variable load
• Power supply and speed control options

9.2 Select Pump Type

For most low-flow, high-pressure systems with clean lubricating fluids,

a three-screw pump is a strong candidate. Consider:

• Three-screw pumps for lubrication, hydraulic oil, and clean fuel
• Twin-screw pumps where gas entrainment, wide viscosity variation, or dry-run capability is needed
• Single-screw (progressive cavity) pumps when solids or shear-sensitive fluids are part of the duty

9.3 Size the Pump Correctly

Once the pump type is chosen:

• Match displacement per revolution and speed to required flow at design conditions.
• Ensure that maximum continuous speed is not exceeded.
• Consider a margin for wear, efficiency losses, and viscosity variations.

Use manufacturer performance data or generic performance curves to check:

• Flow vs speed at your fluid viscosity and temperature
• Power consumption vs pressure
• NPSH requirements

9.4 Ensure Compatibility with Fluid and Operating Conditions

Verify that:

• Materials of construction are compatible with the fluid
• Seals and gaskets can withstand pressure and temperature range
• Clearances are appropriate for viscosity and expected temperature range

9.5 Provide Overpressure Protection

Every positive displacement pump in a low-flow, high-pressure system must be protected

against overpressure. Typical arrangements include:

• Built-in relief valve integrated into the pump casing
• External relief valve installed in discharge piping with return line to tank

Size relief valves for full pump capacity at maximum drive speed. Set opening pressure

below the maximum allowable working pressure of the pump and system.

10. Installation and Piping Best Practices

Correct installation has a significant impact on the performance and service life of

screw pumps in low-flow, high-pressure applications. Key considerations include foundation,

alignment, suction conditions, and discharge piping design.

10.1 Foundation and Alignment

Mount the pump and driver on a rigid baseplate with:

• Grouted or bolted foundation
• Proper alignment of coupling within recommended tolerances
• Allowance for thermal expansion if operating at elevated temperatures

10.2 Suction Piping Design

Good suction conditions are essential for screw pump reliability:

• Use a short, straight, and generously sized suction line.
• Minimize fittings, elbows, and valves close to the pump.
• Install a strainer only if necessary, and ensure it is sized to limit pressure drop.
• Ensure NPSHa exceeds the pump’s NPSHr with a safety margin.

10.3 Discharge Piping Design

Since screw pumps in low-flow, high-pressure systems develop high discharge pressures:

• Ensure piping and components are pressure-rated above relief valve setpoint.
• Provide pressure gauges and, if necessary, pressure transmitters near the pump outlet.
• Install pulsation dampeners only if required; screw pumps often do not need them.

10.4 Filtration and Cleanliness

In applications with tight clearances and high pressures, fluid cleanliness is critical:

• Use appropriate filters on the return line or pressure line.
• Monitor and maintain fluid cleanliness to specified ISO cleanliness codes.
• Include sampling points for fluid analysis.

10.5 Venting and Priming

Before starting, vent air from the pump casing and suction line:

• Open vent connections to allow trapped air to escape.
• Ensure the pump is fully flooded where possible.
• Follow manufacturer procedures for priming if machine is not self-priming under given conditions.

11. Operation, Control, and System Integration

Operating a screw pump in a low-flow, high-pressure system involves speed control, pressure regulation,

and integration with instrumentation and safety systems.

11.1 Speed Control and Variable Frequency Drives (VFDs)

Because discharge flow of screw pumps is directly proportional to rotational speed, VFDs

are commonly used to:

• Modulate flow according to demand
• Soft-start the pump and reduce mechanical stress
• Optimize energy consumption

11.2 Pressure Control Strategies

In low-flow, high-pressure systems, pressure can be controlled by:

• Bypass control: fixed-speed pump with control valve returning excess flow to tank.
• Speed control: VFD adjusts speed to maintain setpoint pressure.
• Combined strategies: speed control for coarse regulation, valve control for fine tuning.

11.3 Monitoring and Protection

Recommended instrumentation includes:

• Pressure transmitters on discharge and, if needed, suction side
• Temperature sensors for fluid and bearings where required
• Flow meters for critical applications
• Vibration and noise monitoring in high-value systems

Protective functions can trip the pump on:

• High discharge pressure
• Low suction pressure (cavitation risk)
• High bearing or fluid temperature

12. Maintenance and Reliability in High-Pressure Service

Screw pumps are known for reliability and long service intervals when properly applied and maintained,

even in demanding low-flow, high-pressure systems.

12.1 Routine Maintenance Tasks

• Periodically check alignment and coupling condition.
• Inspect seals for leakage and wear.
• Monitor bearing temperatures and vibrations.
• Verify relief valve operation and settings.
• Maintain fluid cleanliness and chemical condition.

12.2 Wear and Failure Modes

Common issues in high-pressure screw pumps include:

• Wear of screw flanks and housing surfaces due to contaminated or non-lubricating fluids
• Seal face wear or leakage at elevated pressure or poor lubrication
• Cavitation damage where NPSHa is insufficient
• Overheating if relief valve recirculates full flow continuously

Proactive monitoring and adequate filtration significantly reduce the likelihood of these problems.

12.3 Service Life Expectations

When handling clean, lubricating fluids under well-controlled operating conditions,

screw pumps in low-flow, high-pressure systems can achieve:

• Many tens of thousands of operating hours between major overhauls
• Extended seal life with proper selection and flushing
• Stable performance with gradual, predictable wear

13. Example Specification Tables for Low-Flow, High-Pressure Screw Pumps

The following tables provide illustrative specifications for screw pumps used in low-flow,

high-pressure applications. These are generic examples intended to show typical ranges and

parameters considered in engineering specifications.

13.1 Example Performance Ranges

13.2 Example Technical Specification Sheet

13.3 Example Comparison: Screw Pump vs Alternative for a High-Pressure System

14. Frequently Asked Questions (FAQ)

14.1 What defines a low-flow, high-pressure screw pump application?

A low-flow, high-pressure application is typically one where required pump flow is relatively small

(often below 50 m3/h and frequently below 10 m3/h) but discharge pressure is high (commonly 20–250 bar).

Screw pumps suit these applications due to their ability to generate stable flow at high pressure with

low pulsation.

14.2 Why are screw pumps preferred over gear pumps in some high-pressure systems?

Screw pumps are often preferred because they:

• Produce smoother, less pulsating flow
• Operate at lower noise levels
• Can achieve higher efficiency at certain viscosities
• Offer robust continuous-duty performance at high pressure

14.3 Can screw pumps handle non-lubricating or abrasive fluids?

Traditional three-screw pumps are best suited to clean, lubricating fluids. For non-lubricating or

abrasive fluids, special designs (such as certain twin-screw or progressive cavity pumps) may be

more appropriate, but careful material and configuration choices are required. Not all screw pumps

are suitable for abrasive service.

14.4 How is flow controlled in a low-flow, high-pressure screw pump system?

Flow can be controlled by:

• Adjusting pump speed with a variable frequency drive
• Using bypass or recirculation valves to divert excess flow
• Combining speed control with control valves for fine regulation

14.5 Do screw pumps require pulsation dampeners?

In many cases, screw pumps do not require pulsation dampeners because their flow is inherently smooth

compared to reciprocating pumps. However, in very sensitive systems or where extremely precise

pressure stability is required, additional dampening may be considered.

14.6 What maintenance is needed for screw pumps in high-pressure service?

Maintenance typically includes:

• Regular inspections of seals and bearings
• Monitoring vibration, temperature, and noise
• Maintaining fluid cleanliness and proper lubrication
• Checking and periodically testing relief valve operation

14.7 Are screw pumps self-priming?

Many screw pumps have self-priming capability, especially when used with viscous or lubricating fluids.

However, for reliable operation, flooded suction and proper venting are usually recommended, particularly

at high pressures and critical services.

15. Summary and Key Takeaways

Screw pumps are a proven, reliable solution for low-flow, high-pressure systems in

a wide range of industrial applications. Their advantages include:

• Stable, low-pulsation flow ideal for sensitive equipment and precise control
• High discharge pressure capability in a compact footprint
• Good efficiency with lubricating fluids across a broad viscosity range
• Low noise and vibration compared to many alternative pump types

Three-screw and twin-screw pumps dominate in clean oil, lubrication, hydraulic, and fuel systems,

while single-screw (progressive cavity) designs serve specialized duties with challenging fluids.

Correct selection, installation, and operation ensure long-term, reliable performance in demanding

low-flow, high-pressure environments.