What is the role of metal detector in the food industry
Metal detectors are used in the food industry to detect and eliminate threats of metal contaminants falling into food commodities. Detecting these particles can make or break a small business, and also protect established manufacturers from losing product quality and brand due to metallic contaminant recalls.
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Metal detection and its place in food production
The food industry produces goods with maximum efficiency, resulting in the maximum possible number of high-quality products in a given period. To protect brands and consumer attractiveness, many companies have adopted and implemented advanced metal detection technologies in their product lines. Metal detectors used in contemporary food production are a lower cost alternative to X-ray inspection systems and have a lower cost of ownership, and the detection technology meets HACCP requirements. This ability to detect defects and inappropriate products before they reach the consumer is a powerful advantage any food business has, helping to prevent any brand-damaging recalls or legal action that may come from manufacturing unsafe products.
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How do metal detectors work?
There are several types of metal detectors that work with different detection methods. In the food industry, metal detectors apply the transmitter-receiver method (see diagram). These metal detectors are equipped with a transmitter coil and two receiver coils. The transmitter coil generates a constant electromagnetic field. When a metal particle passes the detector it interferes with the electromagnetic field, causing a signal to be detected by the receiver coils. The electronic unit in the metal detector analyzes and evaluates this signal and indicates the presence of metal contamination. As a rule, metal detectors in the food industry are equipped with automatic rejection units that directly separate the contaminated product from the production line.
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Why are metal detectors used in the food industry?
Metal detectors for food are mainly used for the purpose of consumer protection. Despite the utmost care, metal contamination of food products during the entire production process cannot be ruled out. Metal particles that enter the product during the production process or are already present in the raw materials may cause serious injury to consumers. The consequences for the producing company are numerous and serious and include compensation claims and expensive withdrawals. Greater and longer-term damage is caused by negative brand image and loss of consumer confidence due to impure food products. Metal detectors for food provide effective protection against ferrous and non-ferrous metals (aluminum, stainless steel, etc.). It can be installed at every step of the production process and can be used for many different applications, for example to screen bread, bakery products, meats, sausages, fruits, vegetables, dairy products, spices, sugar, etc. In addition to consumer protection, metal detectors are also used to protect machinery. Even the smallest particles of metal can lead to machinery failure. Expensive repairs and production downtime are the consequences, often followed by a drop in revenue.
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Terms of Food Products
The conditions of food products can have a significant impact on metal detection. The electrical conductivity in foods such as cheese, fresh meat, warm bread, jam, and pickles can generate a signal in a metal detector even though the metal is not present. This phenomenon is known as the ‘product effect’. It is best to be aware of this phenomenon and work with the metal detector supplier or manufacturer to determine the best means to compensate for the effect of the product. Carrier detectors are the most common; Examples are presented in Figure 3. Many variations of manual, semi-automatic and fully automatic rejection mechanisms are possible, such as air blowers, push-arms, retractable conveyor bed, reversible conveyor sliding gate, ink mark or programmer, shift conveyors and an automatic clutch.
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Metal Detector Program
The official metal detector program will help ensure product quality. Metal detectors can be used at various stages of production. The combination of screening of finished ingredients, bulk ingredients and the product gives the best performance. Detectors may need to be placed after certain processing equipment (such as downsizing) that is prone to breaking or chipping metallic materials. A sensitivity criterion (or standards) should be established for the entire facility. An important aspect of this is the determination of the minimum agreed upon particle type and size. For example, a typical detection criterion for a final product may be to remove all non-magnetic spherical particles larger than 2.0 mm and all spherical and magnetic particles larger than 1.5 mm. Only detectors that meet these criteria will be considered for purchase and installation. Conditions must be clearly indicated on the side of any installed reagent and samples of correct diameters must be provided for unit testing.
Metal detectors work excellently for finding valuable objects like coins and jewelry. Since such a device can detect ferrous and non-ferrous metals, it can be pretty easy to pinpoint where your targets are buried.
So, this hobby can be worth the effort and time investment because you can find valuables that you can exchange for money.
However, what metals cannot be detected by a metal detector?
Metal detectors emit electromagnetic fields to locate metals buried underground. These electromagnetic fields change from time to time as the device listens to waves that come from conductive elements.
That said, a metal detector will not detect metals with poor electrical conductivity.
Metal detectors are high-end devices. They do not work on magnetism but rather by detecting electromagnetic fields. For this reason, the device can detect both ferrous and non-ferrous metals.
Ferrous metals consist of iron. Such a type of metal is corrosive and magnetic. They are known for their durability, hardness, and strength. Some examples of ferrous metals are alloy steel and cast iron, both detectable by a metal detector.
On the other hand, non-ferrous metals, such as copper and aluminum do not contain iron. For this reason, non-ferrous metals are non-magnetic. Some non-ferrous items are coins and jewelry, which a metal detector can also detect.
That said, metal detectors can locate almost all types of metals. The reason is that the device works by transferring an electromagnetic field from the search coil into the ground. However, it is essential to note that there are metals that a metal detector cannot detect.
Once the electromagnetic field hits a metal target, it will retransmit an electromagnetic field into the device’s receiver coil. Any metal target will send a signal regardless of whether it is ferrous or non-ferrous.
For this reason, there are only a few metals that a metal detector cannot detect. These metals have low electrical conductivity, making it impossible to create an electromagnetic field.
