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Multi-aperture metal detector

23 October 2016

Fortress recently collaborated with Sparc Systems to design a ferrous-only five-lane multi-aperture metal detector. This was customised to inspect foil spice packs and integrated with a five-lane Sparc checkweigher.

For Fortress, this installation was deemed an engineering triumph, with the multi-aperture technology being integral to the project’s success. The entire five-lane combination metal detector and checkweighing unit measured 1.5m wide by 2.2m long.

Phil Brown, European sales director, says: "As far as we are aware, no one has accomplished such a compact combined system integrating a multi-aperture metal detector head. Custom built in 12 weeks and installed in March 2016, the five-lane system boosted inspection throughput from 200 to 1000 packs/min, increased metal detection sensitivity by more than 300% and reduced equipment footprint by over a half. All other options would have meant compromising on space, metal detection sensitivity or waste, making this project a non-starter."

Fortress says it cost about £40,000 less than acquiring five individual metal detector and checkweighing combination systems. Another feature is the transport mechanism that automatically separates metal contaminant rejects from weight rejects and places them in accessible BRC-approved lockable bins.

Brown continues: "Due to the foil packaging, x-ray might have been considered the only option. Yet, the small footprint meant it would be technically impossible to accomplish a fully integrated five-lane checkweigher and inspection unit with today’s x-ray technology."

How the spices are processed was another swing factor for multi-aperture. Brown explains: “This Ferrous-only system can identify metal contaminants measuring 1.2mm, compared to 5mm on a single aperture metal detector covering each line. While the risk obviously needs to reflect the product, when you consider the processing involved in preparing these spice blends, increasing the sensitivity to catch smaller wire swarfs that might pass through a sieve is huge advancement.”