Roller Size Grading Machine
Roller diameter grader that separates round and oblong fruit into size bands by carrying product over rollers with progressively widening gaps.
How it works
Product is fed onto a bed of rotating rollers set with a gap that widens along the length of the machine. Each piece rides the rollers until it reaches the point where the gap exceeds its smallest dimension, then it drops through onto a cross-belt or into a collection flume. Because the rollers also rotate the product, pieces are measured on their smallest axis rather than in one fixed orientation.
Stepped-gap designs use discrete sections with fixed gaps instead of a continuous taper; they are simpler but give fewer, coarser bands.
Suitable for
Apples, pears, citrus and other round fruit; potatoes and onions; oblong root vegetables; any product where market value depends on diameter band.
Not suitable for
Flat or irregular shapes that do not roll; very soft fruit that deforms under roller pressure; product requiring grading by weight rather than dimension; long thin products like carrots and cucumbers, which need a different mechanism.
Material & compliance
Rollers and frame in SUS304 (EN 1.4301) or food-grade polymer sleeves on stainless shafts; catch belts in food-grade PU or PVC. Gap adjustment accessible from the operator side without dismantling the bed.
Supplied with CE declaration of conformity and DoC on request; material certificate EN 10204 3.1 available for contact parts.
Selection notes
Decide how many bands you actually sell — every extra band adds cross-belts, collection points and labour, and most packhouses over-specify this. Confirm whether gap adjustment is mechanical (spanner and gauge) or motorised, because changeover between crops is where the time goes. Check roller surface: hard rollers bruise soft fruit, and sleeved rollers wear.
When you should not buy this machine: If your contract is on weight, a diameter grader will not satisfy it — buy a weight grader instead. Also skip it for product that does not roll reliably; irregular shapes will ride past their correct band and contaminate every grade.
Key specifications
| Parameter | Value |
| Capacity | 1500-8000 kg/h (TYPICAL, confirm with factory) |
| Size bands | 3-6 grades (TYPICAL) |
| Motor power | 1.5-4.0 kW (TYPICAL) |
| Contact material | SUS304 (EN 1.4301) |
| Roller type | Diverging roller or stepped gap (TYPICAL) |
| Power supply | 380V/3P/50Hz or 415V/3P/50Hz, customizable |
Specification values are industry-typical ranges for this machine class and are not verified against a specific factory datasheet. Replace them with measured factory data before publication.
FAQ
How accurate is diameter grading compared with weight grading?
Diameter grading measures geometry, not mass. For round fruit of uniform density the two correlate well; for variable-density or irregular product they diverge. If the buyer pays by weight, grade by weight.
Can I change grade bands between crops?
Yes, on most designs. Mechanical adjustment takes longer and needs a gauge; motorised adjustment from the HMI is faster but costs more. Ask how long a full changeover takes on the machine you are quoted.
Will rollers bruise soft fruit?
Hard steel rollers can. Sleeved rollers or polymer-coated shafts reduce bruising, and lower bed speed helps. For soft or delicate product, test on your own fruit before committing.
Related equipment
This unit is one stage of a complete processing line. For the full range of sorting and grading equipment, or to compare this model against the weight grading machine, see the complete equipment catalogue. Capacity, material grade and utility requirements can be confirmed through a quote request.
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