Knowledge centre · Product properties
A practical guide to fluid categories: liquids, semi-fluids and pastes in filling
Put the product in the right category and most filling decisions answer themselves. This is the taxonomy we use every day.
1. Four practical categories
Product names vary, but flow behaviour falls into a small number of categories. Classifying by behaviour — not by label — is the fastest route to a correct machine:
| Category | Typical products | Filling approach |
|---|---|---|
| Thin liquids | Milk, beverages, edible oil, syrups | Gear pump or piston filler; high speed, simple handling |
| Semi-fluids | Creams, gels, sauces, dressings | Rotor pump filler; accurate, gentle dosing |
| Pastes and fillings | Bean paste, jam, meat filling, thick cream | Rotor pump filler (larger chamber); handles high viscosity |
| Particle-bearing fluids | Chilli sauce, fruit jam, dressings with herbs | Seatless rotor pump; particles pass intact |
2. Why the category matters more than the name
Two products called "sauce" can sit in completely different categories — a thin vinaigrette and a thick chilli paste. Equipment quoted by name alone will be wrong for one of them. When you communicate with a supplier, describe behaviour: viscosity at filling temperature, particle size and concentration, shear sensitivity. The category then places the product, and the product places the pump.
3. The boundaries shift with temperature
Categories are not fixed. Chocolate is a semi-fluid at 45 °C and a solid at room temperature; honey behaves very differently between cold and warm filling. If your process temperature varies, state both ends of the range so the machine is sized for the worst case — the cold, thick condition usually dictates the pump.
4. From category to machine in four answers
- Product type and viscosity (at filling temperature) — selects pump family.
- Fill volume — sizes the pump chamber and servo resolution.
- Container — shapes nozzle and handling design.
- Required output — sets speed, head count and line layout.
With these four answers, the machine configuration follows. Where the category is unusual, a filling test with your product settles it.