Supplied by Fortress Technology, the new linear Stealth detector had to meet stringent retailer requirements for selling ‘naked nuts’, which speculate that its new honey-coated range must be inspected for metal contaminants prior to own-label packaging.
Additionally, Trigon required a supermarket spec metal detector that was sensitive enough to adapt to the fine oil and sugar tolerances.
For logistical reasons, a small-footprint, wide-head Stealth metal detector engineered to inspect the fried, dried and seasoned nuts on a conveyor before entering the chute and falling into the one-ton sacks (over 1,000 kilograms), was the most viable and accessible option, said Fortress.
The low profile nuts – combined with the inspection speed – meant that a kicker would be incompatible and it would be virtually impossible to isolate and divert contaminated products with naked products.
With insufficient space to accommodate a flap style reject, Fortress instead engineered a retracting band conveyor and reject mechanism.
Rather than a typical tongue and groove conveyor, the rollers on Trigon’s moveable easy-clean, food-grade belt are rounded. The metal detector which sits at the front of the conveyor calculates precisely how long the contaminated nuts will take to reach the end of the conveyor band, communicating via the metal detector control system.
The belt then smoothly retracts back on a sliding rail rolling the rejected nuts into the dedicated bin located beneath the conveyor, resuming its inspection position in just seconds, according to Fortress.
Hourly manual tests are the only reported source of daily waste, which the lead engineer estimated to be less than 0.05% of the total production – below the food manufacturing average, which can reach double figures.
The system is capable of detecting ferrous and non-ferrous particles as small as 1.0mm and stainless steel particles down to 1.5mm – a level of sensitivity Fortress sales manager Jaison Anand attributed to the aperture dimensions.
“Aperture size is critical to optimal operation,” he explained. “If aligned to the size of the product being inspected it delivers the best performance. That’s why we installed a wide yet low profile metal detector head on the Trigon honey nut line.”
A longstanding advocate of Fortress equipment, Trigon Snacks, which last year celebrated it’s half century milestone, was in fact one of the food safety specialist’s first UK snack customers.