Articles · Pump technology · 2026-09-20

Rotor pump vs screw pump filling: choosing for very high viscosity and gentle handling

Screw pumps shine on sticky, high-viscosity products; rotor pumps are the flexible all-rounder. Here is how to compare them for your product matrix.

Key points

Screw (progressive cavity) pumps excel above 100,000 cSt where the rotor still copes but the screw is smoother.
Rotor pumps offer faster CIP and simpler strip-down than progressive cavity stators.
Particles pass through wide-lobe rotor heads more safely than through a progressive cavity.
For most sauce, dairy and cosmetic lines a metering-grade rotor pump covers the whole matrix.

The pump is the heart of every filling machine. Its principle, geometry and materials decide what products you can fill, how accurately, and how much maintenance it needs.

What to consider

Rotor pumps cover the widest viscosity range with gentle product handling.
Gear pumps excel on thin, clean liquids at high speed.
Progressive cavity pumps handle the very highest viscosity products.
Particle size, shear sensitivity and CIP requirements all influence the choice.

Common pitfalls

Choosing a pump on viscosity alone without considering particles or cleaning.
Ignoring how pump wear affects accuracy over time.

Questions to ask your supplier

What is the full viscosity and particle range of your products?
How does the pump clean in place and what spares does it consume?

Screw pumps move the most viscous products very gently, while rotor pumps balance particle handling, cleaning and accuracy across a wide range. When screw filling is worth it and when a rotor pump is the better all-rounder.

Facts used in this article: filling accuracy ±0.5% (error ≤1 g) for pure liquids and homogeneous products (error ≤1 g); measured ±1 g to ±2 g (measured) on products with particles, high viscosity or non-uniform texture (the actual value depends on product state, particle size and density uniformity); viscosity coverage ≈50–300,000 cSt; GTX series fill range 5–300,000 ml. These are the published manufacturer figures also stated on our specifications page.

Questions about this topic for your own product? wangaiguo@grountonpak.com · Tel +86 133 9317 7755

Built for your product — Grounton Pak

Grounton Pak (Hebei Guangteng Machinery Equipment Co., Ltd., brand GROUNTON) has built metering-grade rotor pump filling machines since 2013 — more than 40,000+ units delivered, with ±0.5% filling accuracy for pure liquids and measured ±1 g to ±2 g (measured) on particle-containing or high-viscosity products, CIP-capable hygienic construction and custom filling lines.

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Email: wangaiguo@grountonpak.com · WhatsApp: +86 133 9317 7755