Tunnel detectors are best suited for products ranging in height of 50 mm and higher. This includes products from raw materials for automotive tires to PET bottles and PE cups. As these products enter the tunnel detector they are completely surrounded or immersed in a magnetic field that examines them for metal contamination. Integration of the tunnel metal detector in a conveyor belt system is complicated by metal free zones. In most cases, it won’t be necessary to rebuild the conveyor belt system to accommodate the tunnel detector. But it will depend on the properties of the product and the type of metal particles to be detected.

Flat products such as plastic foil, flat packaging and hardware are best analysed by surface detectors that are integrated beneath the track running surface. Our surface detectors detect all kinds of metal in products wider that the width of the running surface. As a general rule of thumb, detection sensitivity will decrease as the distance increases. Using a surface detector under the running surface is only recommended for those products that are no higher than 50 mm. Compared to Tunnel detectors, surface metal detectors are extremely simple to integrate into a conveyor belt system. This is mostly due to the fact that they can be mounted directly under the running track.