Dosing and big bag systems
Gravimetric screw feeder
Load-cell weighing feeder for powders and granulates, with ±0.5 % accuracy and a report for every batch. Integrates into mixing, packing and processing lines, at rates of 50 – 5,000 kg/h.
Also known as: weigh feeder · gravimetric dosing unit · loss-in-weight feeder
Specifications
| Throughput | 50 – 5,000 kg/h |
|---|---|
| Dosing accuracy | ±0.5 % |
| Hopper volume | 100 – 2,000 L, to order |
| Product contact material | AISI 304 / 316L stainless |
| Motor power | 0.37 – 7.5 kW |
| Drive | Gearmotor with frequency inverter |
| Weighing | Load cells, with correction for material in flight |
| Options | Interchangeable screws · hopper vibrator · hopper agitator |
The figures above are the ranges we build routinely, not construction limits. We design and manufacture any capacity, power rating and envelope to order — including below or above the ranges in the table.
Industrii
- Chemicals
- Food
- Pharma
- Individually sized — on your material, throughput and space
- Technical proposal and price, normally within 48 hours
- Installation, commissioning and service from our own plants
When to choose it
The concrete situations where this machine is the right answer — and the one where we recommend something else from our range.
The recipe demands exact quantities, and a deviation means a rejected lot or wasted raw material — two-stage dosing with correction for material in flight holds the deviation to ±0.5 %.
You need traceability: the system issues a weighing report for every batch, with the recipe used.
You dose materials with different flow behaviour from the same installation — the screws are interchangeable, per material type.
The material is sticky and bridges in the hopper: a hopper vibrator or agitator is added.
When this is NOT the right machine
If you only need to move material from one point to another, without a guaranteed quantity, the weighing and the control are costs you will not use.
Vezi Screw conveyorHow it works
The gravimetric screw feeder provides weighed dosing of powdered and granular materials in mixing, packing and processing lines — anywhere the recipe demands exact quantities and where deviations mean rejects or wasted raw material.
The feed hopper is mounted on load cells, and the extraction screw discharges the material while the system weighs continuously. Dosing runs in two stages — high rate for rapid filling, fine rate as the target is approached — with automatic correction for the material in flight, for an accuracy of ±0.5 % on every dose.
The control system stores the recipes, issues a weighing report for every batch and communicates with the existing line automation. Product contact parts are built in AISI 304/316L stainless, with interchangeable screws for materials of differing flow behaviour and a hopper vibrator or agitator for sticky powders.
±0.5 % accuracy
Continuous load-cell weighing, with correction for material in flight.
Two-stage dosing
High rate plus fine rate — fast dosing without overshooting the target.
A report for every batch
Full traceability of the recipes, stored in the control system.
Line integration
Direct communication with the mixing or packing line automation.
Variante constructive
What actually differs between them — not just what they are called.
Gravimetric dosing (weighed)
The hopper stands on load cells and weighs continuously. Accuracy is guaranteed regardless of variations in material density — the version described on this page.
Volumetric dosing (without weighing)
A speed-controlled screw only. Less expensive, but accuracy depends on the density of the material staying constant: if the raw material varies from lot to lot, so does the quantity dosed.
With a hopper vibrator or agitator
For sticky powders that bridge above the screw and stop flowing.
With interchangeable screws
Several flights, with different pitches, for materials of differing flow behaviour dosed from the same installation.
Frequently asked questions
Question not answered here? Write to us — an engineer replies, nu un robot.
What does ±0.5 % accuracy mean in practice?
That at a target dose of 100 kg, the deviation stays within ±0.5 kg. The accuracy comes from two-stage dosing — high rate until close to target, then fine rate — plus automatic correction for the material in flight between the screw and the receiver at the moment of stopping.
What happens if the density of the raw material varies from lot to lot?
With gravimetric dosing it does not matter: mass is weighed, not volume. That is the difference from a volumetric feeder, where a density variation translates directly into a quantity deviation.
What report do I get for each batch?
The system stores the recipes and issues a weighing report for every batch.
Will it connect to our line automation?
Yes, the control communicates directly with the mixing or packing line automation. The protocols supported are in the specification table, in the “Line communication” row.
Our material bridges in the hopper — will dosing stop?
That is what a hopper vibrator or agitator is for: it releases the material and keeps it flowing to the screw. Tell us what you are dosing and how sticky it is — the choice between vibrator and agitator depends on exactly that.
