INSTALLATION GUIDE

How should a metal detector be installed?

All CO-EL metal detectors work with a balanced magnetic field, controlled by a control board that discriminates between the variations induced by metallic impurities and variations induced by the product to be checked. To avoid false alarms, it's necessary to eliminate all the causes of variation in the magnetic field:

Main trouble causes:

• Distance between the detection head and nearby metallic parts
• Incorrect installation of the conveyor belt
• Coil Effect

Distance of nearby metallic parts

The magnetic field, even though screened in the detection head, is never perfectly contained in the sides of the detection head.
For this reason, the "detection zone" is bigger than the opening of the metal detector, and must be kept free from metal parts.
When installing a metal detector head, every fixed metal part must be kept at a distance at least equal to the passage height.
Every moving metal part must be kept at a distance at least equal to 1.5 times the passafe height instead.

Metal detector head installed on a conveyor belt

A conveyor belt must respect several conditions to allow a metal detector to work properly.
CO-EL metal detectors are supplied with plastic feets to keep the metal detector head insulated from the conveyor's frame. Feets unproperly mounted may lead to false alarms.
The belt must slide on a non-conductive plane. A belt rubbing for long time on a metallic plate may be contaminated by metallic impurities, generating false alarms.  To avoid electrostatic pertutrbations, we recommend the use of and antistatic conveyor belt.

Coil Effect

The magnetic field generated by the metal detector is interlocked with the head's support structure.
If the structure is poorly fixed, an electromotive force may be generated  that unbalances the metal detector's field provoking a false alarm.
To avoid this all conductive parts composing the metal detector conveyor stucture must be welded or well fixed. For these reasons it's necessary to use plastic rollers; if it is not possible, mount rollers with an insulating bearing: one roller's side must be kept conductive to eliminate electrostatic discharges.