Metal detector | Advantages and disadvantages of needle detector
With the improvement of people's living standards, the quality of life requirements are not satisfied with being able to eat and use, but put forward a higher goal of good food and good use. Only high-quality products can stand on the market and win consumers' Dear. Metal detectors are widely used in various processing and packaging industries such as food, pharmaceutical, and daily chemical industries. As a key control point of HACCP, manufacturers are encouraged to carry out quality control to ensure that the final products that enter the market will not cause harm to consumers.
Advantages of metal detectors:
1. Easy to operate.
2. Economical and reliable.
3. Wide range of applications.
Disadvantages:
1. Sensitivity is not enough.
2. Affected by the environment.
3. Affected by the test object.
The principle of the metal detector is that the magnetic field of the metal entering the detector causes the magnetic field to change, the sensor starts the signal, and drives the automatic rejection device, such as the flap, the push rod, etc., to remove the impurities. However, some products themselves contain water, salt and other components, which also cause metal-like interference to the magnetic field.
Advantages and disadvantages of needle detector
The advantages of the needle detector are not to be elaborated, as the price is relatively cheap, suitable for most manufacturers. Has been accepted by the majority of users. At present, the performance of the needle detector provided by the regular manufacturers in China can be comparable to that of the imported needle detector.
A. Although the needle detector technology is only improved and improved, since the principle of the needle detector is the principle of magnetic induction, only ferromagnetic metals (iron, cobalt, nickel and alloys containing these metal impurities) can be detected, and other highs cannot be detected. Fine metal of purity. That is to say, if the product contains a small amount of high-purity non-ferromagnetic metal impurities other than ferromagnetic metals, the needle detector has no way to detect it.
B. The inside of the probe of the needle detector is a permanent magnet, but after years of use, the magnetic force will gradually decrease and the sensitivity may decrease. This also poses a safety hazard for industrial testing. The needle detector must be periodically tested and calibrated with the needle detector nine-point test method to ensure efficiency. For products that need to detect all metal foreign objects (clothes, handbags, etc. without metal fittings), an all-metal detector can be selected according to actual needs.