Belt Conveying in Pet Food Plants

A pet food conveyor carries coated kibble, which is fat on the outside of a porous brittle piece. The fat transfers to everything: the belt surface, the belt carcass if it can get in, the seams, the scrapers, the frame and the floor underneath.

Once it is in, it stays. A fabric reinforced belt with a mechanical joint absorbs fat into the carcass and into the joint, and no surface cleaning reaches it. That absorbed fat oxidises, it smells, and it carries the previous recipe into the next one.

Carryover here reaches the label. Single protein diets, poultry free formulations and prescription products depend on the previous recipe being absent, and a conveyor is a long product contact surface that is rarely named in a changeover procedure.

Breakage is the other cost. Kibble is fragile, and transfer points, scrapers and steep inclines with cleats all break pieces that then report to the fines screen.

A belt conveyor is chosen on capacity and lift in every industry. Here the fat and the palatant decide what the belt and its joint may be made of.

Belt materials that fat does not penetrate, with joints that do not absorb, so cleaning the surface actually cleans the belt.

A frame and structure specified for the cleaning regime, without hollow sections, ledges or blind fasteners where fat and product can collect out of reach.

The conveyor named in the changeover procedure with a cleaning method and a verification step, and transfer points designed to keep kibble whole.

A recycling plant cannot specify against a known product at all, so the separation steps upstream decide what the belt has to survive, and separation placed late protects nothing.

Belt selection starts from fat resistance. A homogeneous belt or a modular plastic belt with no absorbent carcass keeps the fat on the surface where cleaning can reach it; a fabric belt with a mechanical joint does the opposite and is a long term carryover source.

The frame is then specified to the same standard as in a food plant, because the cleaning problem is the same and the material is stickier. Open sections, drainable surfaces, hand removable guards and nothing horizontal under the carry side.

Transfer points are designed for the product rather than for the layout. A short drop onto a moving belt at a matched speed keeps kibble whole; a long fall onto a stationary surface does not. Scrapers are chosen for the fat without being aggressive enough to break product.

Then the conveyor enters the changeover procedure. A cleaning method, a verification step and a position in the sequence from restricted recipes downwards, so the carryover risk on a long contact surface has an owner.

• Belt material chosen for fat resistance, with no absorbent carcass or joint.
• Frame and guards specified to a hygienic standard, drainable and without ledges.
• Transfer points designed as short drops onto a matched belt speed to keep kibble whole.
• Scrapers chosen to remove fat without breaking product.
• Conveyor named in the changeover procedure with a cleaning and verification step.
• Production sequenced from restricted recipes downwards so cleaning does less work.

• Fat and palatant level, which decides the belt material and the cleaning interval.
• Belt joint type, since an absorbent joint is a permanent carryover source.
• Claim sensitivity of the recipes sharing the line.
• Kibble fragility and the number of transfer points on the route.
• Cleaning regime, dry or wet, and what the frame has to tolerate.
• Changeover frequency and the time available for cleaning.