Metal detection element for turn-key packaging lines

Phil Black - PII Editor 30/05/2014

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Lock Inspection (part of the Loma Group) has been selected to supply the metal detection element of a new turn-key packaging line for a global speciality chemicals company, on the back of its reputation for delivering best-in-class performance on dry food, chemical and pharmaceutical products.

Last year the chemical company contracted automation and systems integration specialist Pacepacker Services to design and install a new line for packing and palletising lanolin pearls at its UK factory. Because lanolin is used as a base ingredient in many moisturisers, ointment, lotions and sun cream products, it is crucial that not even the tiniest metallic particles find their way into the bulk product, which is supplied to personal care and cosmetic manufacturers in the form of waxy pearls. For this reason, Pacepacker selected an inspection equipment partner who could guarantee the highest levels of sensitivity and reliability.

Whilst wet or conductive products are usually inspected at lower frequencies due to product interference, dry products can be inspected at mid to high frequencies as this gives heightened detection performance for non-ferrous and stainless steel metals.

Three Lock metal detectors – two INSIGHT HD conveyorised systems and an INSIGHT PH VF ‘Pharmaceutical Vertical Fall metal detector – are now up-and-running at the company’s East Yorkshire facility, screening bulk, free-flowing product and 25kg sacks of lanolin pearls for metal contamination.

The two INSIGHT HD Metal Detector systems are installed on sack packing lines. After being filled, closed and ‘kicked’ into a lie flat position, 25kg sacks pass through the detectors, which are tuned to 286kHz – the optimum frequency for this application. Out of specification sacks are diverted onto a reject conveyor to a quarantine area, with the contaminate-free sacks continuing on to the robotic palletiser.

The Vertical Fall INSIGHT Metal Detector, Lock’s flagship inspection system for free-falling powders and granules, was chosen for its compact dimensions. It slots beneath the out-flow of the box filling system and can check up to 3,000kg of free-flowing product per hour, ensuring that metallic contaminants are isolated before the lanolin is packed into boxes of varied capacity – up to 25kg.

“It wouldn’t have been possible to install a conveyorised system on the box filling line because the size of the aperture needs to match the size of the product – you can’t pass a 1kg box through an aperture that was specified for a 25kg box and expect to achieve good detection performance. For the box filling line, therefore, the optimum solution was to check the product for metal before it was packaged,” explains Mark Jackson-Nichols, the Loma / Lock Sales Engineer who worked with Pacepacker on this project.

“Space was extremely tight, not just on this line, but for the overall system. We had to be mindful of this when choosing which equipment to specify, so on this score, Lock’s INSIGHT Vertical Fall was ideal,” adds Paul Wilkinson. “We knew before this project that Lock had an outstanding reputation for the highest detection performance and were confident that they would deliver a solution our client would be happy with. Working with them on this project has only reinforced this perception.”

Having worked with Lock Inspection on a number of occasions and aware that Lock’s single frequency machines are widely known to be as being the best in the business for dry, high sensitivity applications, Pacepacker had no hesitation in making Lock’s metal detection equipment an integral part of the solution it was proposing.

Pacepacker’s Business Development Manager Paul Wilkinson says: “We’ve worked with Lock on projects stretching back many years and know that their inspection equipment delivers unbeatable performance on dry products.”

Explaining why this is, Hitesh Hirani, Lock’s Technical Director, says: “Whether tablets, snacks, powders or granules, Lock’s metal detectors come out on top in tests. The build of our metal detectors – both in terms of coil construction assembly and stability – means they are particularly suited to being operated at mid and high range frequencies; our pharmaceutical unit is widely acknowledged as the most sensitive metal detector available and is the only machine on the market to operate at 1MHz.”