Every fruit packing line runs on cylindrical brushes. Potatoes, carrots, apples, citrus and mangoes each need a different bristle stiffness, and using the wrong one either leaves soil on the fruit or bruises the skin it is supposed to clean. For equipment builders and packhouse engineers, the fill chart below is the core of the specification.
Matching Fill Stiffness to Produce
| Produce | Fill | Why |
| Potatoes, beets | Stiff PP or PP/wire mix | Heavy soil, thick skin |
| Carrots | Medium PP | Skin scuffs easily when wet |
| Apples, pears | Soft PP | Wax and skin must survive |
| Citrus | Medium PP, often with green fibre mix | Penetrates dimpled peel |
| Mango, avocado | Very soft PP | Thin skins, high value |
| Onions, garlic | Stiff PP | Dry peeling action |
The pattern to remember: the higher the value and thinner the skin, the softer the fill. A bruised mango is unsellable; a dusty carrot is not.
Food-Safe Materials Are Non-Negotiable
Brushes on washing lines contact food directly, so fill and core must comply with the destination market’s rules. For US-bound lines, materials should meet FDA food contact requirements, and equipment design falls under FSMA’s sanitary framework — confirm compliance certificates with your supplier before the line is built, not after inspection. Stainless cores and shafts are standard for washdown zones; galvanised components fail quickly under chlorine and organic acids.
Sizing the Roller
Three dimensions define the roller:
- Diameter — typically 120–200 mm for washing tunnels; smaller diameters fit sorting tables.
- Length — band width; continuous production means any length without tooling charges.
- Spiral pattern — open wind for rinsing action, dense wind where soil load is heavy.
Rotation speed matters as much as geometry: fruit rides on the brush crests, and too much speed turns cleaning into throwing. Equipment designers usually run 100–200 rpm and let the spiral direction move fruit gently sideways to prevent end-pile-up.
The Replaceable-Sleeve Advantage
Washing brushes are wear parts — bristles soften and splay over months of wet abrasion. A two-part design, where a brush sleeve slides onto a reusable stainless core, cuts lifetime cost substantially: the core survives years, and only the sleeve is replaced. Ask for this configuration when budgeting a new line.
Ordering Checklist
Send: produce type, roller OD/length, shaft diameter, wet or dry section, and target market (for compliance certificates). Factory-direct supply with in-house winding handles custom lengths in 15–20 days, with sample rollers for trial runs.
Roller options: Spiral Brushes · Spiral Roller Brush
