WHITE PAPER Consequently, metal detection systems do not give a 100% security, even with regard to the detection of metal objects. Metal detection systems cannot detect non-metallic items such as bone, glass, wood or plastic. The metal detectable plastics used in the construction of food industry standard cleaning equipment and utensils only contain a small percentage of metal detectable material. Consequently, metal detection systems only work if the fragments of this equipment are large enough to detect (given other detector limitations). Most manufactures of metal detection equipment will provide ‘calibration test pieces’, to check the function of the detector against ferrous (iron) and non-ferrous metals. These are regularly used by food manufacturers to verify the performance of their metal detection systems. Some manufacturers of metal detectable plastic equipment also provide a test kit, that enables the food manufacturer to find out what size of metal detectable plastic can be detected by their detector/in their product. However, very few food manufacturers do this. STUDY 1: THE DETECTABILITY OF METAL DETECTABLE PLASTICS This investigation focussed on determining the detectability of metal detectable plastics used in the production of food industry cleaning equipment and utensils, such as brush blocks, shovels, hand scoops, buckets, etc. Method A Detectronic metal detector (Model No.606-250, Figure 2) was used to investigate the detectability of a range of metal detectable plastics, available as test kits from suppliers of metal detectable plastic equipment to the food industry. An example of a metal detectable plastic test kit is shown in Figure 3. Detectronic model no. 606-250 Speed: 20 meter/minute Settings: Neutral product Product compensation: -5 Aperture Width: 350 cm Aperture Height: 250 cm Figure 2. The Detectronic metal detector (Model No.606-250) Figure 3. Metal detectable plastic test kit (Vikan) The detector was calibrated for optimal detection of a 1.5 mm diameter ferrous (iron) metal test piece. These settings were then used to assess the detectability of each of the different sized pieces of metal detectable plastic in each supplier test kit. Results The results of the investigation to assess the detectability of different metal detectable plastics are shown in Figure 4. Vikan A/S - Department of Research & Development 2 Copyright © 2021 Vikan A/S · All Rights Reserved
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