Gear Pump vs Screw Pump
Gear pumps and screw pumps both use positive displacement, but they move liquid through different internal geometries. Gear pumps transport liquid in spaces between gear teeth and the casing. Screw designs move liquid along helical elements; a progressing-cavity design differs from a multi-screw arrangement. Compare the actual liquid, viscosity at temperature, lubrication, solids, required flow and differential pressure. The word “screw” alone does not identify a suitable configuration, and neither family is a universal substitute for the other.
Quick comparison
Compare operating requirements, not category names alone. This qualitative table describes selection questions; it does not certify a particular product or rank the two options.
| Factor | Gear pump | Screw pump |
|---|---|---|
| Operating principle | Liquid is carried around meshing gears; internal and external gear designs differ. | Liquid advances along helical geometry; rotor–stator and multi-screw constructions differ. |
| Liquid characteristics | Check lubricity, abrasiveness, solids and compatibility with the gear design. | Identify the exact screw construction before assessing lubricity, solids and compatibility. |
| Viscosity | Evaluate inlet filling, slip, torque and starting conditions. | Evaluate inlet feeding, torque, speed and any rotor–stator material constraints. |
| Flow selection | Assess displacement and speed with slip at the duty pressure. | Assess displacement, speed and leakage for the specific screw configuration. |
| Pressure selection | Confirm differential pressure and mechanical limits; include overpressure protection. | Confirm allowable pressure for the selected stages or screw design and pressure protection. |
| Materials | Review gears, casing, bearings where wetted, seals and elastomers. | Review screws or rotor, casing or stator, seals and any elastomers. |
| Temperature | Include startup, normal and upset temperatures when checking clearances and seals. | Include temperature effects on clearances, seals and the stator where fitted. |
| Installation | Check suction pipe losses, inlet conditions, alignment and maintenance access. | Check feed conditions, dry-running restrictions and access required by the exact design. |
When to consider Gear pump
A gear pump may be considered for a liquid-transfer duty when the fluid characteristics and required pressure are compatible with the specific gear arrangement.
- For an oil-transfer application, state viscosity at startup and operating temperature, cleanliness and lubricating characteristics.
- For liquids that become difficult to move when cold, provide the startup procedure and temperature range; ask whether heating or another configuration is needed.
- Report abrasive contamination or particles explicitly. Do not assume that a gear pump suitable for one liquid can handle a slurry with the same viscosity.
When to consider Screw pump
A screw pump may be considered when a specific screw configuration fits the liquid and process, but the internal construction must be identified before comparing it with a gear pump.
- For a progressing-cavity arrangement, evaluate the rotor–stator combination, feed conditions and material compatibility for the intended medium.
- For a multi-screw arrangement, confirm the design’s liquid, lubrication and cleanliness requirements. Do not transfer assumptions from a single-screw product.
- Where flow variation or product handling matters, specify the acceptable process result and operating range rather than assuming a universal pulsation or shear advantage.
Key selection factors
Prepare the following information so the proposed configuration can be assessed for the actual duty.
- Fluid description: Identify the medium, lubricity, abrasive contamination, particle content and any tendency to solidify.
- Rheology and temperature: Provide viscosity with units at operating and starting temperatures. Explain whether viscosity changes with shear or time.
- Exact construction: Confirm internal or external gear, progressing cavity or multi-screw arrangement, and the materials of wetted components.
- Duty and control: Specify flow, differential pressure, operating range, speed control, duty cycle and overpressure protection requirements.
- Site conditions: Provide inlet pressure or tank level, pipe layout, power supply, available heating and maintenance space.
Narrow your shortlist
Use the conditions below to identify what to investigate next. A shortlist still requires confirmation against the complete process and installation.
| Requirement / condition | What to evaluate | Pump type or configuration to investigate |
|---|---|---|
| Clean oil transfer | Viscosity, lubricity, inlet losses and differential pressure. | Evaluate gear and an appropriate multi-screw design. |
| Sludge or a liquid containing particles | Particle size, concentration, abrasion and rotor–stator compatibility. | Investigate a suitable progressing-cavity design; confirm the exact product. |
| Large viscosity change between startup and operation | Starting torque, feed conditions, temperature control and speed. | Compare the proposed gear and screw configurations at both conditions. |
| Process sensitive to flow variation | Permitted variation, control method and verified behavior at the duty point. | Evaluate the specific configurations; request supporting data. |
| A screw pump is specified without further details | Number and arrangement of screws, stator construction and intended medium. | Clarify the screw family before comparing or replacing equipment. |
When the answer is not clear
If the screw construction, liquid viscosity or contamination is unknown, the two categories cannot be compared as interchangeable products. Send the application, medium, flow, pressure, temperature, material requirements and operating conditions. Include the existing model information when assessing a replacement.
Engineering background for this comparison
These references explain general pump principles. HENVO product facts come from the linked HENVO product pages; no external manufacturer specifications are assigned to HENVO products.
Representative HENVO products
These existing products have real product images and populated technical fields. They are examples to investigate, not equivalent replacements or confirmed selections for your process.
Buyer questions
Use these answers to identify the information needed before comparing quotations or requesting a model recommendation.
What is the main difference between gear and screw pumps?
Both are positive-displacement pumps. Gear pumps carry liquid around gear teeth; screw pumps move it through helical geometry. The construction within each family affects suitability.
Are all screw pumps suitable for the same liquids?
No. A progressing-cavity design and a multi-screw design have different internal arrangements. Confirm the exact construction and its liquid requirements.
Is a screw pump always the preferred choice for a viscous liquid?
No. Compare the actual viscosity, temperature, pressure, feed conditions and required process behavior. A suitable gear pump may also be evaluated.
Can I choose between these pumps using motor power?
No. Motor power alone does not establish flow at pressure or suitability for the liquid. Provide the complete duty point and startup conditions.
Why must I specify particles and lubricity?
They affect wear, feeding and compatibility with internal components. Requirements vary by design, so report the liquid characteristics instead of relying on a broad pump label.
What information is needed for a replacement assessment?
Provide the existing model, medium, flow, differential pressure, viscosity and temperature range, materials, suction layout, drive and duty cycle. Explain what the replacement must achieve.
Prepare your comparison inquiry
Send the comparison context and process information below. Identify any unknown values so the next step can be a configuration review.
- Application and existing model if replacing
- Medium, lubricity, particles and abrasion
- Required flow and differential pressure
- Viscosity with units at operating temperature
- Startup temperature and operating range
- Required materials and sealing arrangement
- Suction layout, controls and power supply
- Duty cycle, maintenance space and country