Belt Conveying in Food Production

A food conveyor has to be cleaned, often daily and often wet, and the cleaning has to reach everywhere product or water can go. The belt itself is usually specified carefully: a food grade material, a smooth or positively driven surface, a defined finish.

The frame is where it goes wrong. Hollow box sections that hold water, blind fasteners, overlapping plates with a capillary gap, horizontal ledges under the carry side and a drive guard that cannot be removed without tools: each of these is a place where product, water and warmth meet, and that is the definition of a harbourage site.

Tracking is the second practical issue. A belt that wanders spills, and spillage in a food plant lands on the floor and in the frame, which turns a mechanical nuisance into a cleaning and microbiological one.

And products vary. A conveyor carrying coated snacks, wet dough or chilled portions has different problems in each case, from fat soaking into a belt to a product that sticks and then dries on.

What a belt conveyor has to do is the same as anywhere. What changes is that every surface it touches has to be cleanable to the plant standard, including the ones nobody specified.

A machine whose frame, guards and drives are specified to the same hygienic standard as the belt, with no hollow sections, no blind fasteners and no horizontal ledges that collect.

A cleaning method that matches what the plant actually does, including whether the machine can be wet cleaned at all and how it dries afterwards.

A belt that tracks reliably, so spillage is not the daily source of the contamination the cleaning is fighting.

A mining or mineral plant decides the same conveyor on the measured friction angle and lump size, because an incline taken from a table gives back the material it was meant to lift.

The hygienic design is specified as a whole machine. Open tubular or solid frame members rather than closed box sections, fasteners that can be cleaned around or removed, sloped surfaces that drain, guards that come off by hand, and drives and bearings positioned so they are not over the product.

The belt is then chosen for the product and the cleaning. A modular plastic belt can be opened and cleaned in place and handles wet duty well; a solid homogeneous belt has no joint to harbour anything and suits dry fatty products; a fabric belt is cheaper and rarely appropriate where washing is daily.

Tracking is designed rather than adjusted. A positively driven belt removes the problem entirely on short runs; where a plain belt is used, the loading has to be central and the pulleys square, because a tracking adjustment is a symptom treatment.

Then the cleaning method is confirmed with the plant. Wet cleaning needs drainage, drying and electrical protection to match; dry cleaning needs access and vacuum rather than compressed air, which spreads what it removes.

• Frame, guards and drives specified to the same hygienic standard as the belt.
• No hollow sections, blind fasteners or horizontal ledges in the product zone.
• Belt type chosen for the product and the cleaning regime, not only for the duty.
• Positively driven belts or central loading to remove tracking problems at the cause.
• Drainage, drying and electrical protection matched to a wet cleaning regime.
• Dry cleaning by vacuum rather than compressed air, with the access to do it.

• Cleaning regime, wet or dry and how often, which governs the whole machine specification.
• Product characteristics: fat, moisture, stickiness and temperature.
• Allergen matrix where the conveyor is shared between recipes.
• Belt joint, since a joint is a harbourage site and some belts have none.
• Drainage and drying after a wet clean, which is where water sits if it is not designed for.
• Tracking arrangement, because spillage is a hygiene issue rather than a tidiness one.