What are the different uses of different forms of metal detectors?

Metal materials engineering can be engaged in the design and manufacture of metal materials, material surface modification, metal materials, inorganic non-metallic materials, polymer materials, composite materials, functional materials and other fields in machinery and chemical industry, energy and environment, electronics and information, metallurgy and mining, power and power and national defense construction, as well as automobile, petrochemical, semiconductor and other industries, as well as material production organization, technical management and material testing, failure analysis and other technical supervision work. You can also engage in research and teaching in colleges and universities. At the master's or doctoral level, they can be engaged in the research of basic theory, design, manufacturing, analysis and testing of new materials in the fields of material surface engineering technology, aerospace technology, biomedical engineering technology, etc.

Conveyor Belt Metal Detector: This is currently the most widely used equipment, and the translational conveyor belt can be suitable for placing various types of products for transmission inspection, especially suitable for the inspection needs of packaged products, providing final inspection before shipment. Moreover, the equipment has a variety of sensitivity parameter adjustments, which can be suitable for the detection needs of products in different industries!

Pipeline metal detector: mainly used to inspect paste, sealed pipes on the assembly line. It is convenient to detect and remove metal impurities in pipes, mainly used for the detection of tablets, capsules, granules (plastic particles, etc.), and powdered items!

Falling metal detector: mainly used to detect powdery, small particles and other granular products, currently mainly used in plastics, rubber and other industries!

Pressure conveying metal detector: mainly used in pressure conveying lines, products with high pollution requirements. Liquid or viscous items can be inspected before filling or sealing, which can effectively improve the detection accuracy!

Vacuum conveying metal detector: suitable for vacuum production lines with high production requirements, this kind of products have high requirements for the use of the environment, and are not used much in the market, mainly used in the chemical industry!

Summary. Hello dear<>

I am asking a question and answer the main text Erjiu, the detection range of metal detectors has 1, in the military, metal detectors can be used to detect metal mines. 2. In the field of security, it can detect portable or hidden ** and crime tools. 3. In terms of archaeology, it is possible to detect the ancient tombs where metal objects are buried, and find gold and silver treasures, jewelry or other metal products in the ancient tombs.

4. In engineering, it can be used to detect underground metal burials, such as pipelines and pipelines; In mineral exploration, it can be used to detect and discover natural gold grains. <>

<> metal detector detection range.

Hello dear<>

I am asking a question and answer the main text Erjiu, the detection range of metal detectors has 1, in the military, metal detectors can be used to detect metal mines. 2. In the field of security, it can detect portable or hidden ** and crime tools. 3. In terms of archaeology, it is possible to detect the ancient tombs where metal objects are buried, and find gold and silver treasures, jewelry or other metal products in the ancient tombs.

4. In the project, it can be used and only used to detect underground metal burials, such as pipelines and pipelines; In mineral exploration, it can be used to detect and discover natural gold hail memogranes. <>

<> Kiss now expands for you: Precautions when using a metal detector: A metal detector is a metal detector that consists of a metal detector and an automatic rejection device, with the detector as the core part.

The system can use the alarm signal to drive the automatic rejection device, etc., so as to remove metal impurities from the production line. There are three groups of coils distributed inside the detector, namely the coarse state ** transmitting coil and two equivalent receiving coils, and the high-frequency variable magnetic field is generated by the oscillator connected by the middle transmitting coil, and the induced voltage of the receiving sail opening coils on both sides cancels each other out before the magnetic field is disturbed and reaches a balanced state.

Because the metal detector is operated by the principle of electromagnetic induction, so at present, in many metal substances, such as iron, steel, chromium, carbon steel, tungsten carbide and other metals with conductivity and magnetism, because of the magnetic field of the detection equipment has a significant effect. Metals with high resistance but non-magnetic, such as brass, copper, aluminum, and lead, are relatively easy to detect because they are conductors. However, some pure, high-resistance and non-magnetic metals, such as 304 and 316 in stainless steel, are difficult to detect!

In order to meet the inspection needs of most industry sectors, conventional metal detectors are able to accurately detect most of the metals mentioned above. Although some hard-to-detect metals pose a big problem for the equipment, by analyzing the characteristics of the metals and optimizing the operating frequency and detection accuracy of the equipment, it is also possible to achieve high-precision detection results for these metals.

The accuracy and reliability of a metal detector depends on the stability of the electromagnetic transmitter frequency, which typically operates from 80 to 800 kHz. The lower the operating frequency, the better the detection performance of iron; The higher the working frequency, the better the detection performance of high-carbon steel. The sensitivity of the detector decreases as the detection range increases, and the size of the sensing signal depends on the size of the metal particles and conductivity.

Due to the pulsation of the current and the filtering of the current, the metal detector has certain limits on the delivery speed of the inspected item. If the delivery speed exceeds a reasonable range, the sensitivity of the detector will decrease.

In order to ensure that sensitivity does not deteriorate, it is essential to select the right metal detector to suit the product being inspected. Generally speaking, the detection range is controlled to a minimum as much as possible, and for products with good high-frequency sensing, the detector channel size should match the product size. The adjustment of the detection sensitivity is determined by referring to the center of the detection coil, which has the lowest induction.

The measured value of the product will change with the change of production conditions, such as changes in temperature, product size, humidity, etc., which can be adjusted and compensated by the control function.

Pellets are repeatable, have the smallest surface area and are the most difficult to detect for metal detectors. Therefore, the spheroids can be used as a reference sample for detection sensitivity. For non-spherical metals, the detection sensitivity depends largely on the position of the metal, and different positions have different cross-sectional areas, and the detection effect is different.

For example, iron is more sensitive when passing longitudinally; High-carbon steels and non-ferrous steels are less sensitive. Iron is less sensitive when passing laterally, while high-carbon steel and non-ferrous are more sensitive.

In the food industry, systems typically use higher operating frequencies. For foods such as cheese, the response of high-frequency signals is proportionally increased due to their intrinsic high-frequency sensing performance. Moist fatty or salty substances, such as bread, cheese, sausages, etc., have the same electrical conductivity as metals, and in this case, in order to prevent the system from giving false signals, the compensation signal must be adjusted to reduce the sensing sensitivity.

Femtosecond detection found that there are three main types of metal detectors: electromagnetic induction type, X-ray detection type, and microwave detection type.

Usually a metal detector consists of two parts, namely a metal detector and an automatic rejection device, with the detector as the core part. There are three groups of coils distributed inside the detector, namely the ** transmitting coil and two equal receiving coils, and the oscillator connected by the middle transmitting coil generates a high-frequency variable magnetic field, and the induced voltage of the receiving coils on both sides cancels each other out before the magnetic field is disturbed in the idle state to reach a balanced state. As soon as the metal impurities enter the magnetic field area, the magnetic field is disturbed, this equilibrium is broken, and the induced voltages of the two receiving coils cannot be cancelled out, and the unoffset induced voltages are amplified by the control system and an alarm signal (metal impurities detected) is generated.

The system can use this alarm signal to drive an automatic rejection device, etc., to remove metal impurities from the production line.

According to the mode of conveying the inspected item, the metal detector is usually divided into: channel type, falling body type and pipeline type.

The metal detector should be divided into two parts: the detection circle and the control instrument. The circuit of the control instrument is basically composed of an oscillator, a phase-shifting amplitude modulation bridge, a frequency-selective amplifier, a detection ultra-low frequency amplification, a transmitter pendulum monostable trigger, and a power supply.

Its basic working principle is that a 15kHz sinusoidal voltage is generated by an oscillator and fed to the detection coil, which consists of a main transmitting coil, two sets of secondary coils and an input transformer.

Output transformer composition. Two sets of secondary rings are located on both sides of the main launch coil, and the distance between the main launch coils is equal and symmetrical, and they are intertwined with each other to form a difference coil. When the 15kHz sinusoidal alternating voltage generated by the sine wave oscillator is fed to the main transmission coil through the transmission transformer, the 15kHz alternating magnetic field is generated through a larger alternating current on the main transmitting coil, and the two secondary circles are cut.

Due to the symmetry of the distance from the main transmitter circle and the cross-linking of the two sub-circles, they can induce a 15kHz induced potential of equal amplitude and opposite direction (phase difference of 180°) at the same time to cancel each other out (due to the process relationship, it is impossible for us to make the two sub-circles completely symmetrical to the main circle, and the influence of external shielding materials, the output transformer always has a MV-level unbalanced signal output, and we hope that it is as small as possible). When no metal enters the detection circle, there is only a weak 15kHz equal amplitude unbalanced signal output, this signal is amplified, and the detection becomes a continuous flow voltage and is blocked by the DC blocking capacitor, and cannot enter the post-amplifier, at this time the instrument is in a relatively stable state and stationary. Once the metal enters the detection circle, the metal is in the 15kHz alternating magnetic field, which produces induced potential, eddy current and other phenomena, so that the relative balance of the detection circle is destroyed, and a lower frequency pulsation potential difference is generated, which is loaded on the original equal amplitude unbalanced signal and sent to the amplifier input for amplification.

After the metal signal passes through the first stage amplifier, the amplitude has been amplified by 3000-4000 times, and then sent to the detector to take out the useful signal from the unbalanced signal and then sent to the ultra-low frequency amplifier, and then obtain more than 1000 times amplification. At this time, the metal signal has become an order of magnitude of volts from the original micro-volt signal after several amplifications, and reaches the trigger voltage of the post-stage flip-flop, so that the flip-flop works to drive the relay, send out an alarm signal, and automatically control the required control object. For example, we can determine whether metal is present or not based on the power supply of the load, the signal light is lit, and the signal sound is emitted.