A non-magnetic metal sorting device and method based on an eddy current array sensor

Abstract

The present application relates to non-magnetic metal classification technology, specifically to a non-magnetic metal classification device and method based on eddy current array sensor.The present application solves the problems of poor environmental protection, limited application range, high implementation cost and low classification accuracy of the existing non-magnetic metal classification technology.A non-magnetic metal classification device based on eddy current array sensor, comprising a belt conveyor, a support rod, a transparent supporting plate, an eddy current array sensor, a laser ranging sensor, an impedance analyzer, a signal conditioner and an upper computer.The belt conveyor is horizontally fixed on the ground.The vertical section of the support rod is fixed on the ground beside the belt conveyor.The horizontal section of the transparent supporting plate is fixed on the horizontal end of the support rod.The eddy current array sensor comprises a transmitting coil and four receiving coils.The transmitting coil and the four receiving coils are both horizontally fixed on the upper surface of the horizontal section of the transparent supporting plate, and the four receiving coils are arranged around the transmitting coil.The present application is suitable for the classification of non-magnetic metals.

Description

Technical Field

[0001] This invention relates to non-magnetic metal classification technology, specifically a non-magnetic metal classification device and method based on an eddy current array sensor. Background Technology

[0002] In the process of sorting scrap metals, magnetic metals can be relatively easily sorted out. The remaining non-magnetic metals, mainly composed of copper, aluminum, zinc, tin, and titanium, usually have higher recycling value. However, under current technological conditions, non-magnetic metal sorting technologies suffer from poor environmental friendliness, limited applicability, high implementation costs, and low sorting accuracy due to their inherent limitations. Specifically, existing non-magnetic metal sorting technologies are mainly divided into three types: The first is the heavy media separation method. This method has the following problems: 1. The slurry used is usually highly toxic, and improper handling can easily cause serious environmental pollution, resulting in poor environmental friendliness. 2. It cannot classify non-magnetic metal samples with similar densities, thus limiting its applicability. 3. It has high implementation costs. The second is the optical method. This method has the following problems: 1. It has very strict requirements for the operating environment, thus limiting its applicability. 2. It has high implementation costs. The third method is the eddy current method based on a dual-coil eddy current sensor. The problem with this method is that the classification results are greatly affected by the lift-off height (i.e., the distance between the sensor and the non-magnetic metal sample). Therefore, when external vibrations cause changes in the lift-off height, errors in the classification results are easily introduced, leading to low classification accuracy. Based on this, it is necessary to invent a non-magnetic metal classification device and method based on an eddy current array sensor to solve the problems of poor environmental friendliness, limited applicability, high implementation cost, and low classification accuracy of existing non-magnetic metal classification technologies. Summary of the Invention

[0003] To address the problems of poor environmental friendliness, limited applicability, high implementation cost, and low classification accuracy in existing non-magnetic metal classification technologies, this invention provides a non-magnetic metal classification device and method based on an eddy current array sensor.

[0004] This invention is achieved using the following technical solution:

[0005] A non-magnetic metal sorting device based on an eddy current array sensor includes a belt conveyor, a support rod, a transparent tray, an eddy current array sensor, a laser rangefinder, an impedance analyzer, a signal conditioner, and a host computer.

[0006] The belt conveyor is horizontally fixed to the ground; the support rod has an L-shaped structure, including a horizontal section and a downward-facing vertical section; the vertical section of the support rod is fixed to the ground beside the belt conveyor; the horizontal section of the support rod is located above the belt conveyor; the transparent pallet has an L-shaped structure, including a horizontal section and an upward-facing vertical section; the horizontal section of the transparent pallet is fixed to the horizontal end of the support rod, and the horizontal section of the transparent pallet is located above the belt conveyor.

[0007] The eddy current array sensor includes a transmitting coil and four receiving coils; both the transmitting coil and the four receiving coils are horizontally fixed to the upper surface of the horizontal section of the transparent tray, and the four receiving coils are arranged around the transmitting coil; a laser rangefinder is fixed to the upper surface of the horizontal section of the transparent tray; an impedance analyzer is electrically connected to the transmitting coil; all four receiving coils are electrically connected to the host computer through a signal conditioner; the laser rangefinder is electrically connected to the host computer; and the host computer is electrically connected to the impedance analyzer.

[0008] The dimensions of the transmitting coil and the four receiving coils are identical; the horizontal distances between the transmitting coil and the four receiving coils are equal; the angular distance between the first and second receiving coils is 60°; the angular distance between the second and third receiving coils is 120°; the angular distance between the third and fourth receiving coils is 60°; and the angular distance between the fourth receiving coil and the first receiving coil is 120°.

[0009] A method for classifying non-magnetic metals based on an eddy current array sensor (this method is based on a non-magnetic metal classification device based on an eddy current array sensor described in this invention), the method is implemented by the following steps:

[0010] Step 1: Place the non-magnetic metal sample to be classified on the upper surface of the conveyor belt of the belt conveyor. The non-magnetic metal sample moves with the conveyor belt of the belt conveyor.

[0011] Step Two: When the non-magnetic metal sample moves below the eddy current array sensor, the impedance analyzer outputs a single-frequency excitation signal. This single-frequency excitation signal is transmitted to the transmitting coil, inducing eddy currents in the non-magnetic metal sample, which in turn induces four mutual inductance signals in the four receiving coils. These four mutual inductance signals are transmitted to the signal conditioner, conditioned, and then transmitted to the host computer. Simultaneously, the laser rangefinder measures the lift-off height and transmits the measurement result to the host computer. The lift-off height refers to the distance between the eddy current array sensor and the non-magnetic metal sample.

[0012] Step 3: The host computer acquires the amplitude points of the four mutual inductance signals, selects the point with the largest amplitude from the four mutual inductance signal amplitude points, and then calculates the phase value of the point with the largest amplitude as the characteristic value of the non-magnetic metal sample; the specific calculation formula is as follows:

[0013] Y(α)=arctan(Im(ΔL) / Re(ΔL));

[0014] In the formula: Y(α) represents the phase value at the point of maximum amplitude; Im(ΔL) represents the imaginary part at the point of maximum amplitude; Re(ΔL) represents the real part at the point of maximum amplitude;

[0015] Step 4: Using the lift-off height as the abscissa and the characteristic value of the non-magnetic metal sample as the ordinate, determine the characteristic coordinate points of the non-magnetic metal sample; then, calculate the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample to the first characteristic curve, the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample to the second characteristic curve, the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample to the third characteristic curve, the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample to the fourth characteristic curve, and the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample to the fifth characteristic curve, respectively.

[0016] The first characteristic curve is: y = 0.67825 - 0.00775x; where the value of x ranges from 3mm to 7mm;

[0017] The second characteristic curve is: y = 0.374475 - 0.009825x; where the value of x ranges from 3mm to 7mm;

[0018] The third characteristic curve is: y = 0.2579 - 0.0103x; where x ranges from 3mm to 7mm.

[0019] The fourth characteristic curve is: y = 0.18525 - 0.00675x; where the value of x ranges from 3mm to 7mm;

[0020] The fifth characteristic curve is: y = 0.132825 - 0.004275x; where x ranges from 3mm to 7mm.

[0021] Step 5: Based on the calculation results of Step 4, determine the material of the non-magnetic metal sample, and thus classify the non-magnetic metal samples; the specific determination rules are as follows:

[0022] When the longitudinal distance from the characteristic coordinate point of a non-magnetic metal sample to the first characteristic curve is less than or equal to 0, the material of the non-magnetic metal sample is determined to be titanium.

[0023] When the longitudinal distance from the characteristic coordinate point of a non-magnetic metal sample to the second characteristic curve is less than or equal to 0, the material of the non-magnetic metal sample is determined to be tin.

[0024] When the longitudinal distance from the characteristic coordinate point of a non-magnetic metal sample to the third characteristic curve is less than or equal to 0, the material of the non-magnetic metal sample is determined to be zinc.

[0025] When the longitudinal distance from the characteristic coordinate point of a non-magnetic metal sample to the fourth characteristic curve is less than or equal to 0, the material of the non-magnetic metal sample is determined to be aluminum.

[0026] When the longitudinal distance from the characteristic coordinate point of a non-magnetic metal sample to the fifth characteristic curve is less than or equal to 0, the material of the non-magnetic metal sample is determined to be copper.

[0027] In step two, the excitation frequency and excitation voltage of the single-frequency excitation signal are set by the host computer.

[0028] Compared with existing non-magnetic metal classification technologies, the non-magnetic metal classification device and method based on an eddy current array sensor described in this invention uses the phase value of the largest amplitude point among the amplitude points of four mutual inductance signals as the classification basis, thus possessing the following advantages: First, compared with heavy medium separation methods, the advantages of this invention are: 1. This invention does not require the use of slurry, thereby avoiding environmental pollution caused by improper slurry treatment, and effectively improving environmental friendliness. 2. This invention can classify non-magnetic metal samples with similar densities, thus removing limitations on its applicability. 3. This invention has lower implementation costs. Second, compared with optical methods, the advantages of this invention are: 1. This invention has lower requirements for the operating environment, thus removing limitations on its applicability. 2. This invention has lower implementation costs. Third, compared with the eddy current method based on a dual-coil eddy current sensor, the advantages of this invention are: The classification results of this invention are minimally affected by the lift-up height; even if external vibrations cause changes in the lift-up height, the classification results will not be erroneous, thus effectively improving classification accuracy.

[0029] This invention effectively solves the problems of poor environmental friendliness, limited applicability, high implementation cost, and low classification accuracy of existing non-magnetic metal classification technologies, and is applicable to the classification of non-magnetic metals. Attached Figure Description

[0030] Figure 1 This is a partial structural schematic diagram of the device described in this invention.

[0031] Figure 2 yes Figure 1 Top view.

[0032] Figure 3 yes Figure 1 The left view.

[0033] Figure 4 This is another structural schematic diagram of the device described in this invention.

[0034] Figure 5 This is a schematic diagram of the first to fifth characteristic curves in the method described in this invention.

[0035] In the figure: 1-Belt conveyor, 2-Support rod, 3-Transparent tray, 401-Transmitting coil, 402-Receiving coil, 5-Laser rangefinder, 6-Impedance analyzer, 7-Signal conditioner, 8-Host computer, 9-Non-magnetic metal sample. Detailed Implementation

[0036] A non-magnetic metal sorting device based on an eddy current array sensor includes a belt conveyor 1, a support rod 2, a transparent tray 3, an eddy current array sensor, a laser rangefinder 5, an impedance analyzer 6, a signal conditioner 7, and a host computer 8.

[0037] The belt conveyor 1 is horizontally fixed to the ground; the support rod 2 has an L-shaped structure and includes a horizontal section and a downward-facing vertical section; the vertical section of the support rod 2 is fixed to the ground beside the belt conveyor 1; the horizontal section of the support rod 2 is located above the belt conveyor 1; the transparent pallet 3 has an L-shaped structure and includes a horizontal section and an upward-facing vertical section; the horizontal section of the transparent pallet 3 is fixed to the horizontal end of the support rod 2, and the horizontal section of the transparent pallet 3 is located above the belt conveyor 1.

[0038] The eddy current array sensor includes a transmitting coil 401 and four receiving coils 402; the transmitting coil 401 and the four receiving coils 402 are all horizontally fixed on the upper surface of the horizontal section of the transparent tray 3, and the four receiving coils 402 are arranged around the transmitting coil 401; the laser rangefinder 5 is fixed on the upper surface of the horizontal section of the transparent tray 3; the impedance analyzer 6 is electrically connected to the transmitting coil 401; the four receiving coils 402 are all electrically connected to the host computer 8 through the signal conditioner 7; the laser rangefinder 5 is electrically connected to the host computer 8; the host computer 8 is electrically connected to the impedance analyzer 6.

[0039] The dimensions of the transmitting coil 401 and the four receiving coils 402 are identical; the horizontal distances between the transmitting coil 401 and the four receiving coils 402 are equal; the angular distance between the first receiving coil 402 and the second receiving coil 402 is 60°; the angular distance between the second receiving coil 402 and the third receiving coil 402 is 120°; the angular distance between the third receiving coil 402 and the fourth receiving coil 402 is 60°; and the angular distance between the fourth receiving coil 402 and the first receiving coil 402 is 120°.

[0040] A method for classifying non-magnetic metals based on an eddy current array sensor (this method is based on a non-magnetic metal classification device based on an eddy current array sensor described in this invention), the method is implemented by the following steps:

[0041] Step 1: Place the non-magnetic metal sample 9 to be classified on the upper surface of the conveyor belt of the belt conveyor 1. The non-magnetic metal sample 9 moves with the conveyor belt of the belt conveyor 1.

[0042] Step 2: When the non-magnetic metal sample 9 moves below the eddy current array sensor, the impedance analyzer 6 outputs a single-frequency excitation signal. The single-frequency excitation signal is transmitted to the transmitting coil 401, causing eddy currents to be induced in the non-magnetic metal sample 9, thereby inducing four mutual inductance signals in the four receiving coils 402. The four mutual inductance signals are transmitted to the signal conditioner 7, and after being conditioned by the signal conditioner 7, they are transmitted to the host computer 8. At the same time, the laser rangefinder 5 measures the lift-off height and transmits the measurement result to the host computer 8. The lift-off height refers to the distance between the eddy current array sensor and the non-magnetic metal sample 9.

[0043] Step 3: The host computer 8 acquires the amplitude points of the four mutual inductance signals, selects the point with the largest amplitude from the four mutual inductance signal amplitude points, and then calculates the phase value of the point with the largest amplitude as the characteristic value of the non-magnetic metal sample 9; the specific calculation formula is as follows:

[0044] Y(α)=arctan(Im(ΔL) / Re(ΔL));

[0045] In the formula: Y(α) represents the phase value at the point of maximum amplitude; Im(ΔL) represents the imaginary part at the point of maximum amplitude; Re(ΔL) represents the real part at the point of maximum amplitude;

[0046] Step 4: Using the lift-off height as the abscissa and the characteristic value of the non-magnetic metal sample 9 as the ordinate, determine the characteristic coordinate points of the non-magnetic metal sample 9; then, calculate the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample 9 to the first characteristic curve, the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample 9 to the second characteristic curve, the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample 9 to the third characteristic curve, the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample 9 to the fourth characteristic curve, and the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample 9 to the fifth characteristic curve, respectively.

[0047] The first characteristic curve is: y = 0.67825 - 0.00775x; where the value of x ranges from 3mm to 7mm;

[0048] The second characteristic curve is: y = 0.374475 - 0.009825x; where the value of x ranges from 3mm to 7mm;

[0049] The third characteristic curve is: y = 0.2579 - 0.0103x; where x ranges from 3mm to 7mm.

[0050] The fourth characteristic curve is: y = 0.18525 - 0.00675x; where the value of x ranges from 3mm to 7mm;

[0051] The fifth characteristic curve is: y = 0.132825 - 0.004275x; where x ranges from 3mm to 7mm.

[0052] Step 5: Based on the calculation results of Step 4, determine the material of non-magnetic metal sample 9, and thus classify non-magnetic metal sample 9; the specific determination rules are as follows:

[0053] When the longitudinal distance from the characteristic coordinate point of the non-magnetic metal sample 9 to the first characteristic curve is less than or equal to 0.01, the material of the non-magnetic metal sample 9 is determined to be titanium.

[0054] When the longitudinal distance from the characteristic coordinate point of the non-magnetic metal sample 9 to the second characteristic curve is less than or equal to 0.01, the material of the non-magnetic metal sample 9 is determined to be tin.

[0055] When the longitudinal distance from the characteristic coordinate point of the non-magnetic metal sample 9 to the third characteristic curve is less than or equal to 0.01, the material of the non-magnetic metal sample 9 is determined to be zinc.

[0056] When the longitudinal distance from the characteristic coordinate point of the non-magnetic metal sample 9 to the fourth characteristic curve is less than or equal to 0.01, the material of the non-magnetic metal sample 9 is determined to be aluminum.

[0057] When the longitudinal distance from the characteristic coordinate point of the non-magnetic metal sample 9 to the fifth characteristic curve is less than or equal to 0.01, the material of the non-magnetic metal sample 9 is determined to be copper.

[0058] In step two, the excitation frequency and excitation voltage of the single-frequency excitation signal are set by the host computer 8.

[0059] In specific implementation, the transparent tray 3 is made of acrylic; the excitation frequency of the single-frequency excitation signal is set to 40kHz; the excitation voltage of the single-frequency excitation signal is set to 1V; the inner radius of the transmitting coil 401 is 3mm, the outer radius is 5mm, the height is 1mm, and the number of turns is 100; the inner radius of the four receiving coils 402 is 3mm, the outer radius is 5mm, the height is 1mm, and the number of turns is 100; the horizontal distance between the transmitting coil 401 and the four receiving coils 402 is 10mm.

[0060] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for classifying non-magnetic metals based on an eddy current array sensor, characterized in that: This method is based on a non-magnetic metal classification device based on an eddy current array sensor. The device includes a belt conveyor (1), a support rod (2), a transparent tray (3), an eddy current array sensor, a laser rangefinder (5), an impedance analyzer (6), a signal conditioner (7), and a host computer (8). Among them, the belt conveyor (1) is fixed horizontally on the ground; the support rod (2) has an L-shaped structure and includes a horizontal section and a vertical section facing downward; the vertical section of the support rod (2) is fixed on the ground next to the belt conveyor (1); the horizontal section of the support rod (2) is located above the belt conveyor (1); the transparent pallet (3) has an L-shaped structure and includes a horizontal section and a vertical section facing upward; the horizontal section of the transparent pallet (3) is fixed to the horizontal end of the support rod (2) and the horizontal section of the transparent pallet (3) is located above the belt conveyor (1); The eddy current array sensor includes a transmitting coil (401) and four receiving coils (402); the transmitting coil (401) and the four receiving coils (402) are all horizontally fixed on the upper surface of the horizontal section of the transparent tray (3), and the four receiving coils (402) are arranged around the transmitting coil (401); the laser rangefinder (5) is fixed on the upper surface of the horizontal section of the transparent tray (3); the impedance analyzer (6) is electrically connected to the transmitting coil (401); the four receiving coils (402) are all electrically connected to the host computer (8) through the signal conditioner (7); the laser rangefinder (5) is electrically connected to the host computer (8); the host computer (8) is electrically connected to the impedance analyzer (6); This method is implemented using the following steps: Step 1: Place the non-magnetic metal sample (9) to be classified on the upper surface of the conveyor belt of the belt conveyor (1), and the non-magnetic metal sample (9) moves with the conveyor belt of the belt conveyor (1); Step 2: When the non-magnetic metal sample (9) moves to the bottom of the eddy current array sensor, the impedance analyzer (6) outputs a single-frequency excitation signal; the single-frequency excitation signal is transmitted to the transmitting coil (401), causing eddy currents to be induced in the non-magnetic metal sample (9), thereby causing four mutual inductance signals to be induced in the four receiving coils (402); the four mutual inductance signals are transmitted to the signal conditioner (7), and after being conditioned by the signal conditioner (7), they are transmitted to the host computer (8); at the same time, the laser range sensor (5) measures the lift-off height and transmits the measurement result to the host computer (8); the lift-off height refers to the distance between the eddy current array sensor and the non-magnetic metal sample (9); Step 3: The host computer (8) collects the amplitude points of the four mutual inductance signals, selects the largest amplitude point from the amplitude points of the four mutual inductance signals, and then calculates the phase value of the largest amplitude point as the characteristic value of the non-magnetic metal sample (9); the specific calculation formula is as follows: ； In the formula: This indicates the phase value at the point of maximum amplitude. Represents the imaginary part of the point with the largest amplitude; Represents the real part of the point with the largest amplitude; Step 4: Using the lift-off height as the abscissa and the characteristic value of the non-magnetic metal sample (9) as the ordinate, determine the characteristic coordinate points of the non-magnetic metal sample (9); then, calculate the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample (9) to the first characteristic curve, the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample (9) to the second characteristic curve, the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample (9) to the third characteristic curve, the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample (9) to the fourth characteristic curve, and the longitudinal distances from the characteristic coordinate points of the non-magnetic metal sample (9) to the fifth characteristic curve. The first characteristic curve is: ;in, The value range is 3mm to 7mm; The second characteristic curve is: ;in, The value range is 3mm to 7mm; The third characteristic curve is: ;in, The value range is 3mm to 7mm; The fourth characteristic curve is: ;in, The value range is 3mm to 7mm; The fifth characteristic curve is: ;in, The value range is 3mm to 7mm; Step 5: Based on the calculation results of Step 4, determine the material of the non-magnetic metal sample (9), and classify the non-magnetic metal sample (9) accordingly; the specific determination rules are as follows: When the longitudinal distance from the characteristic coordinate point of the non-magnetic metal sample (9) to the first characteristic curve is less than or equal to 0.01, the material of the non-magnetic metal sample (9) is determined to be titanium. When the longitudinal distance from the characteristic coordinate point of the non-magnetic metal sample (9) to the second characteristic curve is less than or equal to 0.01, the material of the non-magnetic metal sample (9) is determined to be tin. When the longitudinal distance from the characteristic coordinate point of the non-magnetic metal sample (9) to the third characteristic curve is less than or equal to 0.01, the material of the non-magnetic metal sample (9) is determined to be zinc. When the longitudinal distance from the characteristic coordinate point of the non-magnetic metal sample (9) to the fourth characteristic curve is less than or equal to 0.01, the material of the non-magnetic metal sample (9) is determined to be aluminum. When the longitudinal distance from the characteristic coordinate point of the non-magnetic metal sample (9) to the fifth characteristic curve is less than or equal to 0.01, the material of the non-magnetic metal sample (9) is determined to be copper.

2. The method for classifying non-magnetic metals based on an eddy current array sensor according to claim 1, characterized in that: The dimensions of the transmitting coil (401) and the four receiving coils (402) are identical; the horizontal distances between the transmitting coil (401) and the four receiving coils (402) are equal; the angular distance between the first receiving coil (402) and the second receiving coil (402) is 60°; the angular distance between the second receiving coil (402) and the third receiving coil (402) is 120°; the angular distance between the third receiving coil (402) and the fourth receiving coil (402) is 60°; and the angular distance between the fourth receiving coil (402) and the first receiving coil (402) is 120°.

3. The non-magnetic metal classification method based on an eddy current array sensor according to claim 1, characterized in that: In step two, the excitation frequency and excitation voltage of the single-frequency excitation signal are set by the host computer (8).

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