Knowledge centre · Selection
How to select a metering-grade rotor pump for filling
Selection is not a matter of preference — it follows from the product. Work in this order and the machine configuration falls out of the data.
1. Start with the product, not the machine
Three product characteristics decide almost everything: viscosity, particle content and temperature behaviour. Viscosity tells you whether a gear pump (thin liquids) or a rotor pump (medium to high viscosity) is appropriate; particle content determines whether a piston-type machine is usable at all.
| Viscosity band | Typical products | Pump type |
|---|---|---|
| ≈50–1,000 cSt | Milk, beverages, edible oil | Gear pump |
| 1,000–50,000 cSt | Creams, gels, sauces without solids | Rotor pump (LX-9 / LX-18) |
| 50,000–300,000 cSt | Bean paste, jams, fillings, with particles | Rotor pump (LX-18 / LX-36 / LX-60) |
2. Size the pump to the fill volume
Fill volume per container selects the rotor pump size. Choose a pump whose working band sits inside your fill range — not at its extreme — so the servo has resolution to correct against weight feedback.
3. Match the filling valve to the product
- Blow-spray valve: thin to medium viscosity, high-speed lines.
- Full-immersion valve: foaming or oxidising products.
- Sauce cut-off valve: viscous products or those with particles — prevents stringing and drip.
4. Then set output, container and automation level
Containers per hour sets the number of heads and the automation level. Container and cap type set the filling station geometry. Only after these are fixed should price be compared — two quotations for “a filling machine” are not comparable until the configuration is.