From what we have seen firsthand, one of the main issues people have with metal detectors is getting the right size to match their processes. People don’t often realize that a larger metal detector shroud has a more difficult time locating metal fragments than a smaller shroud.
A typical rule of thumb is that a smaller electrical field will be able to locate smaller fragments. Metal detectors are simply looking for disturbances in an otherwise static electrical field. Metal distorts this field as it passes through, but a larger metal detector does not work as well because the field already becomes more distorted over a larger area, making it difficult to see the subtle changes from small fragments. There are several things you can do to optimize the size of your metal detector.
First, you should always pass your products through the metal detector when they are at their smallest point. What this means is that they should be checked before they are put into cases or complex packaging.
We have seen customers who have been running entire cases of product through a large metal detector because it will save them money to run multiple products at once, but this generally isn’t true in the long run. Scanning a case with a metal detector means that the system will likely pass over small pieces of metal because the electrical field is too large.
It is better to send each product going into a case through a metal detector individually. This allows you to use a much smaller metal detector, eliminating finer shards of metal. The disturbance they make in the electrical field is far more pronounced on this scale.
There isn’t much in terms of industry standards regarding metal contaminants. Because of this, producers can sometimes take metal detection for granted. Just because you run your product through a metal detector does not make it clear of metal, especially if you have a large detector. Standards aside, customers expect better than metal fragments in their food products, and hurting their expectations hurts business in the long run.
See how metal detectors work for food lines.