Articles · Buyer decision · 2026-09-13
Some products lose quality the moment they are sheared. Screw pump fillers protect them — but only inside the right product window.
Shear breaks down structure. A honey that recrystallises differently, a jam that loses its fruit body, a cosmetic cream that turns watery — these are classic shear damage symptoms from an aggressive dosing pump. A screw pump filler (progressing cavity) moves product with a rotating screw inside a stator, creating a continuous, gentle, low-pulsation flow with very little mechanical agitation. That is why it is the traditional answer for delicate, sticky, high-viscosity products.
A screw pump is not automatically the best choice for every thick product. Consider these four checks:
| Check | Why it matters |
|---|---|
| Fibrous or hard particles | Long fibres can wrap the screw; very hard solids can shorten stator life. Hard, abrasive particles favour a rotor pump with open passage. |
| Fill accuracy at high speed | Screw metering is gentle but can drift at very high cycle rates; servo control is essential for tight tolerance. |
| Cleaning and changeover | Stator and rotor need proper CIP or disassembly; changeover time is longer than a simple seatless rotor chamber. |
| Stator wear | The elastomer stator is a wear part with product-dependent life. Budget for replacement as normal maintenance. |
Both handle high-viscosity product, so the distinction is about the product's nature, not its thickness. We recommend a screw pump filler when the priority is gentleness on a shear-sensitive product with limited particle size. We recommend a rotor pump filler when the product contains larger or abrasive particles, when very high dosing accuracy (±0.5% on pure liquids, error ≤1 g; ±1 g–±2 g measured on particle-containing or high-viscosity products) must be held over a wide fill range (5 ml to 300,000 ml), or when CIP-capable seatless construction is the deciding factor.
Grounton Pak builds both screw and rotor pump fillers, so the screw-versus-rotor decision here is engineering judgement rather than product availability — gentleness for shear-sensitive products and particle tolerance for larger solids both have their place in the range.
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–±2 g on particle-containing or high-viscosity products, CIP-capable hygienic construction and custom filling lines.
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