The technical principle and application of metal detector

The technical principle and application of metal detector


The technical principle and application of metal detector

With the improvement of people’s quality of life, people’s requirements for the quality of food and medicine have become higher and higher. This poses a serious problem for food and medicine manufacturers: how to solve the broken blades and fallen screws in the production process Such as the mixing of metal impurities into the products, causing metal impurities pollution, and causing great damage to the product quality and corporate image of food companies? The application of metal detectors in the production process helps companies solve this problem. To


The working principle of metal detector machine

The working principle of the metal detector machine is very simple. A central transmitting coil and two equivalent receiving coils are installed in a probe. The oscillator emits a high-frequency magnetic field through the transmitting coil in the middle, which is connected to the two receiving coils, but the polarity is opposite. When the magnetic field is not interfered by the outside, the voltage output signals generated by them cancel each other out. Once the metal impurities enter the magnetic field, the signals output by the two output coils cannot be cancelled, and the metal detector machine can detect the presence of metal.

The structure of the metal foil metal detector machine is slightly different. It consists of many copper cables wound around a bobbin. There are many pole magnets in the bobbin. The passage of ferromagnetic metal will cut the magnetic field and generate current in the coil winding. Thus, metal impurities are detected. To


The sensitivity of the metal detector machine

The sensitivity of the metal detector machine is mainly determined by the following factors: opening size, operating frequency, product effects and environmental interference. To

1. The smaller the opening size, the higher the sensitivity of the probe. To

2. The higher the working frequency, the higher the sensitivity. To

3. The product itself will also generate a corresponding signal in the detector coil, which is called product effect. Food composition, temperature, and moisture content all have an impact on the metal detection process. This is because conductive products have a strong influence on the current of the metal detector coil. To

The temperature of the product will also affect the performance of the detector. The sensitivity of the metal detector for detecting thawed products and unthawed products is different. To

External electrical signals and mechanical vibrations from the surroundings will also affect the sensitivity of the metal detector, causing the device to alarm incorrectly. The digital metal detector has an automatic product tracking function that can overcome these problems.


Which metals are difficult to detect

Non-magnetic metals with (relatively) high resistance (such as 304 and 316 stainless steel) are difficult to detect by metal detectors. To

The packaging requirements of the metal detector for the product are not to contain metal, but many manufacturers take into account that some foods have higher requirements on the tightness and light-proofness of the packaging, and use metal composite film for packaging, but the metal composite film will affect the metal detector Therefore, many powerful metal detector manufacturers have developed corresponding testing equipment for this problem. For example, aluminum foil metal detectors can directly detect aluminum-plastic film packaging products. To

Some products with higher requirements for sealing and moisture resistance usually use aluminum foil packaging. Aluminum foil packaging can withstand high temperatures, has good airtightness, and is easy to recycle. However, aluminum foil packaging products are very troublesome for metal detection. The aluminum foil metal detector is a testing equipment specially designed for testing aluminum foil packaged products. To

Detection and rejection

After the metal detector detects the metal, the detector generates an output signal to start the removal equipment to ensure that products containing metal impurities are removed from the production line. Users can choose different rejection methods according to different products. To


Metal detector probe

The characteristics of the metal detector:

1. Digital processing technology-using digital information processing technology, high precision, convenient adjustment and calibration, and good long-term stability. All adjustments are digitally adjusted on the front panel, no need to adjust the potentiometer;

2. It can directly detect products packaged with aluminum-plastic film;

3. Three-frequency metal detector-a metal detector has three built-in working frequencies, which is suitable for the detection of many different products.