Industrial Machinery News

Metal detection systems are often used for inspection and automatic rejection of contaminated product during processing.  One of the most common places where metal detectors are utilized is in the free flowing bulk and powder steps of food production.  Here a metal detection systems is placed inline with the free flowing stream of product.  Typical products being inspected are grains, flour, sugar, filler product and more.  Typically these products are transported in a gravity feed part of the process allowing the raw ingredients to fall at the speed of gravity.  Typically this is a steady enough flow of product that a metal detection system can rely on its speed.  However, under many applications over time the flow of product no longer remains consistent over the days production.  This change in velocity of the free following product changes the way in which a metal detector performs.  Many metal detectors performance and overall sensitivity is based solely on laboratory testing and not ‘real world’ situations.  Another area that can cause a change in system performance is the automatic rejection or removal of contaminated product.  Typically in powdered product a gate or bell diverts the flow of product when metal is detected.  As the gate or flapper moves through the flow of product it can be slowed by the volume of product passing by.  This in turn changes how fast the metal detection system can react to a contaminant.  If you run over the rated amount of flow the system will become sluggish and slow.

So how do you test for gravity feed metal detectors performance?

Here are some tips for testing a gravity feed metal detection system.

1)      Test all products being inspected

2)      Test for minimum and maximum flows

3)      Test regularly throughout the production cycle

4)      Make sure the testing wand is rejected every time.

5)      Inspect rejected material in smaller metal detector and locate contaminant

These simple steps will help you in achieving a higher confidence level with the performance of your metal detector.