FHS-JUN24-PG32+33_Layout 1 11/06/2024 09:27 Page 32
MACHINERY & MACHINE SAFETY
DAIRY INSPECTION SENSITIVITY GETS SMARTER
Food safety specialist Fortress Technology addresses the main metal detection challenges that arise when inspecting dairy applications for contaminants, reviewing how the latest technology is smarter and overcomes a number of sensitivity challenges.
A
pplying the company’s longstanding metal detection expertise, European sales director Phil Brown explains how changing characteristics, product and orientation effect can disrupt product signals and
affect detection sensitivity if not addressed. The food inspection specialist also touches on how digital technologies and machine learning are pushing the innovation boundaries and streamlining inspection processes.
PASSING UNDER THE RADAR Due to high levels of automated processing machinery, the use of tools for maintenance, and other mixing equipment, metal remains the most prevalent contaminant risk in food manufacturing, potentially causing product quality and consumer safety issues. Metal detectors can be deployed to reduce this food
safety risk. However, due to the physics of disturbing the electromagnetic field, the orientation of a metal contaminant can affect whether a contaminant is effectively detected. This phenomenon is known as orientation
effect. It occurs most noticeably when long, thin wire-type metal contaminants are more easily detected if they pass through the metal inspection system in one orientation rather than another. However, this orientation effect is exhibited by any non-spherical contaminant, not just wires. A typical occurrence could be when equipment is calibrated to detect a stainless- steel sphere measuring 2mm in diameter. While it may identify and reject this contaminant, the machine may fail to detect a stainless-steel wire that is slightly smaller in diameter, but longer than 2mm. It does depend on the orientation of the wire as it travels through the detector. Often, it can be easier to detect stainless steel and non-ferrous wires when they pass through
the aperture space sideways or upright, rather than in alignment with the conveyor. This is because of the magnetic permeability of the metal, which is much lower for stainless steel than ferrous metals. Reducing the aperture size in relation to the
product size can be a simple and effective way to increase metal detector sensitivity. This is because sensitivity is expressed as the smallest detectable spherical contaminant travelling through the geometric centre of the aperture. The centre of aperture is always the least sensitive position in the aperture. The idea is to challenge the worst-case scenario. So, if the contaminant is detectable in this position, then it will be more easily detected closer to the aperture walls. Features like single pass product learning and
automatic calibration can also help, as operators are easily able to overcome a potentially changing product effect which will result in maintaining the highest performance levels and lowest levels of false detections.
SENSITIVITY SIGNATURES Dairy product applications are typically wet and conductive, which can present an additional challenge for metal detectors. Cheese, for
32 JUNE 2024 | FACTORY&HANDLINGSOLUTIONS
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54
