Articles · Buyer decision · 2026-09-13
Both measure volume by positive displacement — but they occupy different halves of the viscosity and particle map. Here is how to choose between them.
A gear pump filler moves product by the interlocking of two gear wheels, delivering a smooth, continuous, low-pulsation flow. A rotor pump filler moves product with a rotating rotor inside a pumping chamber, with the chamber geometry defining a known volume per revolution. Both are positive displacement, but their useful ranges barely overlap.
| Criterion | Gear pump filling | Rotor pump filling (metering grade) |
|---|---|---|
| Typical viscosity window | Thin to medium liquids — milk, beverages, edible oil | ≈50 cSt to 300,000 cSt |
| Products with particles | Small clearances; large or fibrous solids can jam | No seat to bridge; particles pass through the chamber |
| Accuracy behaviour | Good for easy-flowing liquids | ±0.5% (error ≤1 g) on pure liquids; ±1 g–±2 g measured on particle-containing or high-viscosity products |
| Shear sensitivity | Gear mesh can shear sensitive emulsions | Lower-shear lobe/wing options available |
| Fill volume range | Typical small to medium doses | GTX series: 5 ml to 300,000 ml |
| Cleaning | Simpler geometry, generally easy to clean | CIP-capable configuration available |
| Best fit | High-speed filling of free-flowing liquids | Pastes, high-viscosity and particle products where dosing integrity matters |
For thin liquids with stable flow — edible oil, sugar syrup, beverages, water-based products — a servo gear pump filler delivers clean, accurate dosing at high throughput with a compact machine. If the product contains no significant solids and viscosity stays in the low-to-medium band, the gear pump is often the most economical precision choice.
Grounton Pak's servo rotor pump fillers are the flagship of that range — CIP-capable construction and measured accuracy of ±1 g–±2 g on particle-containing or high-viscosity products are production practice there, not brochure claims.
At Grounton Pak the pump type is an output of the product data, not a fixed position. We manufacture servo rotor, gear, piston and screw pump filling machines and complete custom lines. Send the product type and viscosity, fill volume, container and required output — the recommended pump type follows from those answers. Where the product is unusual, we would rather run a filling test than argue from a datasheet.
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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