Direct answer
Treat the product as a two-phase process, not a smooth paste
- Record the largest particle in three dimensions, not only a nominal ingredient size.
- Describe particle shape, hardness, fragility and concentration across representative batches.
- Check whether particles float, settle, clump or separate during the expected production hold time.
- Review every restriction in the hopper, valve, hose and nozzle path.
- Measure both total dose and distribution of pieces when piece count or presentation matters.
Why particles change the filling decision
A product can appear pumpable in a sample jug yet behave differently in a valve or nozzle. Long fibres can bridge across an opening, soft pieces can deform, hard particles can jam a moving valve and suspended solids can settle while the machine pauses. The carrier liquid or paste may also flow ahead of the pieces, changing the composition delivered to each pack.
The selection process therefore needs representative product from normal and difficult batches. The trial should run long enough to expose separation, hopper depletion, stoppages and restart—not only a handful of favourable fills immediately after mixing.
| Product characteristic | Why it matters | Trial observation |
|---|---|---|
| Largest particle dimensions | Controls the minimum free passage through valves, hoses and nozzles. | Blockage, cutting, deformation and inconsistent piece transfer. |
| Particle concentration | Changes the probability of several pieces entering the path together. | Dose composition at full, middle and low hopper levels. |
| Settling or flotation | Can change the product presented to the dosing element over time. | Distribution after production pauses and normal replenishment. |
| Fragility or shear sensitivity | Pieces may break or smear through unsuitable restrictions. | Visual condition of pieces before and after filling. |
| Carrier viscosity and temperature | Controls suspension, feed pressure and shut-off behaviour. | Separation, drips, strings and dose stability across the temperature range. |
What counts as a particle in a filling product?
A particle is any discrete solid, fibre, seed, piece or inclusion that behaves differently from the surrounding liquid or paste as the product passes through the filling path. The useful description includes length, width, thickness, shape, hardness, fragility and concentration. A long flexible fibre can bridge a passage even when its thickness is small, while several round pieces can jam together. Supply photographs, dimensions and representative product rather than relying only on an ingredient name.
Which particle properties matter to filler selection?
Particle size, shape, concentration, density, tendency to settle or float, fragility and interaction with the carrier product all matter to filler selection. Also record the product temperature, hold time, mixing method and whether the pieces must remain visually intact. The machine path should be reviewed from the supply vessel to the nozzle exit. A nominal nozzle diameter is not sufficient if another valve, elbow or hose connection creates the smaller restriction.
Why do particles block valves and nozzles?
Particles block valves and nozzles when one or more pieces bridge a restriction, collect at a moving seat, arrive in a cluster or separate from the carrier in a way the passage was not designed to handle. Blockage risk rises during pauses and low-flow conditions because the product may settle or pieces may remain in the shut-off area. The trial should include stop and restart cycles and inspection of retained product. Increasing a nozzle opening can help in some applications but can also affect cut-off, container access and fill control, so it must be tested as part of the whole system.
How can product separation affect fill consistency?
Product separation can make one container receive mainly carrier and another receive more pieces even when the total measured dose appears consistent. Agitation or recirculation may help only when it maintains uniform distribution without damaging the product or introducing air. The correct action depends on particle density, carrier viscosity and vessel geometry. Compare samples from the start, middle and end of a production run and after realistic pauses.
What should a trial prove for a product with pieces or fibres?
A trial should prove that the complete product passes without unacceptable blockage or damage and that both total quantity and inclusion distribution remain acceptable through normal running, pauses, replenishment and restart. Use the smallest nozzle or most restrictive format proposed, the largest representative particles and the full temperature range. Record piece condition, pack cleanliness, valve behaviour, residual product and cleaning access. Agree how many containers will be assessed and what constitutes an acceptable distribution before the trial starts.
Samples and evidence to provide
- Representative product from normal and difficult batches, in sufficient quantity for a sustained run.
- Largest particle dimensions, photographs and approximate concentration.
- Required condition of pieces after filling and any piece-count expectation.
- Product temperature, mixing, hold time and replenishment method.
- Smallest and largest dose and the narrowest container opening.
- Cleaning method and acceptable product recovery or residual-product boundary.
Final suitability depends on the real product, pack, environment and integrated process. Use representative samples and agree the acceptance method before the machine design is fixed.