Multifunctional coil module for metal detector and metal detector

Abstract

The present invention relates to a multifunctional coil module of a metal detector and a metal detector, which includes a power drive circuit and a signal receiving circuit, and also includes five coils arranged in sequence, and the distances between the second coil and the fourth coil and the third coil are equal, and the distances between the first coil and the fifth coil and the third coil are equal, and the third coil is connected to the output end of the power drive circuit. The coil module also includes a coil switching mechanism, and the coil switching mechanism includes a first selection switch, a second selection switch, a third selection switch and a fourth selection switch, and the first selection switch, the second selection switch, the third selection switch and the fourth selection switch are all single-pole three-throw switches, and the common end is respectively connected to the first coil, the second coil, the fourth coil and the fifth coil, the first output end is connected to the power drive circuit, the second output end is empty, and the third output end is connected to the signal receiving circuit. Compared with the prior art, the present invention has the advantages of strong versatility and space saving.

Description

Technical Field

[0001] The invention relates to the field of metal detectors, and in particular to a multifunctional coil module of a metal detector and a metal detector. Background Art

[0002] Metal detector is an online detection device that detects metal foreign bodies by detecting the changes in the electromagnetic field in the probe window. It is widely used in food, medicine, plastic products, mineral processing and papermaking industries. It is used to detect metal foreign bodies in raw materials and finished products to ensure the quality and safety of products. The detection circuit of the metal detector mainly includes LC oscillation circuit (power circuit), signal receiving circuit, demodulation circuit, control circuit, transmission device and other parts.

[0003] Among them, as the main carrier unit for signal transmission and reception, the coil is an important component of the metal detector. At present, different coil modules are designed for different application scenarios and purposes, but some different types of coils have requirements for the position. For example, as a receiving coil for testing some products with long length and large size, it needs to be far away from the transmitting coil, and this position may conflict with the shielding coil. In addition, even if there is no conflict, in order to meet various working conditions, too many coils need to be configured, which not only increases material costs, but also causes the equipment layout to be too dense or increases the occupied space. Summary of the invention

[0004] The purpose of the present invention is to provide a multifunctional coil module for a metal detector and a metal detector. The coil switching mechanism is formed by a three-throw switch, which can realize the function switching of four coils, thereby realizing four working modes based on five coils, greatly reducing material and space costs.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A multifunctional coil module of a metal detector includes a power driving circuit and a signal receiving circuit, and also includes a first coil, a second coil, a third coil, a fourth coil and a fifth coil, wherein the first coil, the second coil, the third coil, the fourth coil and the fifth coil are arranged in sequence, and the second coil and the fourth coil are at the same distance from the third coil, and the first coil and the fifth coil are at the same distance from the third coil, and the third coil is connected to the output end of the power driving circuit.

[0007] The coil module also includes a coil switching mechanism, which includes a first selection switch, a second selection switch, a third selection switch and a fourth selection switch. The first selection switch, the second selection switch, the third selection switch and the fourth selection switch are all single-pole three-throw switches, and the common end is respectively connected to the first coil, the second coil, the fourth coil and the fifth coil, the first output end is connected to the power driving circuit, the second output end is empty, and the third output end is connected to the signal receiving circuit.

[0008] In some embodiments, the selection switch adopts a double-pole triple-throw switch. Specifically, the coil switching mechanism includes a fifth selection switch and a sixth selection switch, and the fifth selection switch and the sixth selection switch are both double-pole triple-throw switches. The first common end of the fifth selection switch is connected to the first coil, and the corresponding first output end is connected to the power driving circuit, the second output end is empty, and the third output end is connected to the signal receiving circuit. The second common end of the fifth selection switch is connected to the fifth coil, and the corresponding first output end is connected to the power driving circuit, the second output end is empty, and the third output end is connected to the signal receiving circuit. The first common end of the sixth selection switch is connected to the second coil, and the corresponding first output end is connected to the power driving circuit, the second output end is empty, and the third output end is connected to the signal receiving circuit. The second common end of the sixth selection switch is connected to the fourth coil, and the corresponding first output end is connected to the power driving circuit, the second output end is empty, and the third output end is connected to the signal receiving circuit.

[0009] The single-pole triple-throw switch / double-pole triple-throw switch is a relay, or the single-pole triple-throw switch / double-pole triple-throw switch is a manual switch.

[0010] The positions of the first coil, the second coil, the third coil, the fourth coil and the fifth coil are fixed.

[0011] A metal detector comprises a host computer and the coil module as described above, wherein the host computer is connected to each selection switch.

[0012] The host computer is a PC.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1) By forming a coil switching mechanism with a three-throw switch, the function switching of the four coils can be realized, thereby realizing four working modes based on five coils, greatly reducing material and space costs.

[0015] 2) The use of relays can achieve automatic control and improve ease of use.

[0016] 3) The fixed position design provides higher stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the arrangement of the coils of the present invention;

[0018] Figure 2 It is a structural schematic diagram of the present invention;

[0019] Figure 3 is a circuit diagram of a coil switching mechanism;

[0020] Figure 4 is a circuit diagram of another coil switching mechanism;

[0021] Figure 5 This is a schematic diagram of the coil function in the first working mode;

[0022] Figure 6 This is a schematic diagram of the coil function in the second working mode;

[0023] Figure 7 This is a schematic diagram of the coil function in the third working mode;

[0024] Figure 8 is a schematic diagram of coil function in the fourth working mode;

[0025] Fig. 9 is a schematic diagram of a power drive circuit;

[0026] Among them: 1. first coil, 2. second coil, 3. third coil, 4. fourth coil, 5. fifth coil, 6. coil switching mechanism, 7. power driving circuit, 8. signal receiving circuit, 9. coil group, 10. demodulation circuit, 11. host computer. DETAILED DESCRIPTION

[0027] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0028] The main working principle of the metal detector is that inside the probe of the metal detector, the power driving circuit 7 drives the transmitting coil to generate an alternating magnetic field through LC parallel resonance. There is a coil at an equal distance from the transmitting coil. This group of differential coils constitutes a receiving coil. When a metal foreign body passes through the magnetic field, it affects the voltage difference and phase difference between the differential coils. The small signal processing circuit extracts this disturbance signal, thereby realizing the detection of metal foreign bodies passing through the machine. For a metal detector, a good coil system is the key to ensuring the performance and stable operation of the machine. A conventional coil system consists of a transmitting coil and a group of symmetrical receiving coils.

[0029] A multifunctional coil module for a metal detector, such as Figures 1 to 3 As shown, it includes a power driving circuit 7 and a signal receiving circuit 8, and also includes a first coil 1, a second coil 2, a third coil 3, a fourth coil 4 and a fifth coil 5. The first coil 1, the second coil 2, the third coil 3, the fourth coil 4 and the fifth coil 5 are arranged in sequence, and the second coil 2 and the fourth coil 4 are at the same distance from the third coil 3, and the first coil 1 and the fifth coil 5 are at the same distance from the third coil 3. The third coil 3 is connected to the output end of the power driving circuit 7.

[0030] The coil module also includes a coil switching mechanism 6, which includes a first selection switch S1, a second selection switch S2, a third selection switch S3 and a fourth selection switch S4. The first selection switch S1, the second selection switch S2, the third selection switch S3 and the fourth selection switch S4 are all single-pole three-throw switches, and the common end is respectively connected to the first coil 1, the second coil 2, the fourth coil 4 and the fifth coil 5, the first output end is connected to the power driving circuit 7, the second output end is empty, and the third output end is connected to the signal receiving circuit 8.

[0031] The main structure of the coil system is as follows: Figure 5 As shown, it consists of a central transmitting coil and two groups of coils symmetrically on both sides, a total of five coils.

[0032] The third coil is stably used as a transmitting coil, but the first coil 1, the second coil 2, the fourth coil 4 and the fifth coil 5 can switch between different working modes according to the switching states of the corresponding selection switches.

[0033] When the first selection switch S1 and the fourth selection switch S4 are empty, and the third output terminals of the second selection switch S2 and the third selection switch S3 are connected to the common terminal, the first working mode is entered, and the coil functions as follows: Figure 5 As shown, the third coil 3 is used as a transmitting coil, the second coil 2 and the fourth coil 4 are used as receiving coils, the first coil 1 and the fifth coil 5 are not connected to the circuit, and the first working mode is also a normal working mode.

[0034] When the second output terminals of the second selection switch S2 and the third selection switch S3 are connected to the common terminal, and the third output terminals of the first selection switch S1 and the fourth selection switch S4 are connected to the common terminal, the second working mode is entered, and the coil functions as follows: Figure 6 As shown, the third coil 3 is used as a transmitting coil, the second coil 2 and the fourth coil 4 are not connected to the circuit, and the first coil 1 and the fifth coil 5 are used as receiving coils. The coil structure of the second working mode is similar to that of the first working mode, but the distance between the receiving coil and the transmitting coil is larger, which is suitable for testing some products with long length and large size.

[0035] When the first output terminals of the second selection switch S2 and the third selection switch S3 are connected to the common terminal, and the third output terminals of the selection switch S1 and the fourth selection switch S4 are connected to the common terminal, the third working mode is entered. Figure 7 As shown, the second coil 2, the third coil 3 and the fourth coil 4 are used as transmitting coils, and the first coil 1 and the fifth coil 5 are used as receiving coils. The characteristic of this working mode is that the transmitting coil forms a more powerful and uniform alternating magnetic field, which is suitable for testing large-effect products such as salt-rich and oil-rich products in a test environment with obvious directionality in combination with a reasonable signal demodulation circuit.

[0036] When the third output terminals of the second selection switch S2 and the third selection switch S3 are connected to the common terminal, and the first output terminals of the selection switch S1 and the fourth selection switch S4 are connected to the common terminal, at this time, as Fig. 9 As shown, since the induction coils connected to the selection switch S1 and the fourth selection switch S4 and the power driving circuit 7 are wound in opposite directions to the induction coil corresponding to the third coil, the magnetic fields generated by the first coil 1 and the fifth coil 5 are opposite to the third coil 3, thus entering the fourth working mode, as shown in FIG. Figure 8 As shown, the first coil 1 and the fifth coil 5 are used as shielding coils, the second coil 2 and the fourth coil 4 are used as receiving coils, and the first coil 1 and the fifth coil 5 form a reverse alternating magnetic field with the same frequency as the transmitting coil, a certain order of magnitude lower power than the transmitting coil, and a phase lag of 180° compared with the transmitting coil, forming a shielding coil. The magnetic fields of the transmitting coil and the shielding coil cancel each other out and are neutralized at the middle position of the receiving coil and the shielding coil.

[0037] In summary, the switch design of the present application can realize the adaptation of the coil structure of 5 coils to the above four working modes, greatly reducing the space occupation.

[0038] In some embodiments, the selection switch adopts a double-pole triple-throw switch, specifically, Figure 4 As shown, the coil switching mechanism 6 includes a fifth selection switch and a sixth selection switch, and the fifth selection switch and the sixth selection switch are both double-pole triple-throw switches. Figure 4In the figure, S5A1 is the first group of contacts of the fifth selection switch, S5A2 is the second group of contacts of the fifth selection switch, S6A1 is the first group of contacts of the sixth selection switch, and S6A2 is the second group of contacts of the sixth selection switch. The first common terminal of the fifth selection switch is connected to the first coil 1, the corresponding first output terminal is connected to the power driving circuit 7, the second output terminal is empty, and the third output terminal is connected to the signal receiving circuit 8. The second common terminal of the fifth selection switch is connected to the fifth coil 5, the corresponding first output terminal is connected to the power driving circuit 7, the second output terminal is empty, and the third output terminal is connected to the signal receiving circuit 8. The first common terminal of the sixth selection switch is connected to the second coil 2, the corresponding first output terminal is connected to the power driving circuit 7, the second output terminal is empty, and the third output terminal is connected to the signal receiving circuit 8. The second common terminal of the sixth selection switch is connected to the fourth coil 4, the corresponding first output terminal is connected to the power driving circuit 7, the second output terminal is empty, and the third output terminal is connected to the signal receiving circuit 8. In these embodiments, since the linkage control of the first coil 1 and the fifth coil 5, and the linkage control of the second coil 2 and the fourth coil 4 are realized, fewer control signal lines can be occupied.

[0039] In some embodiments, the single-pole triple-throw switch / double-pole triple-throw switch is a relay, which can achieve automatic control and improve ease of use.

[0040] In some embodiments, the single-pole triple-throw switch / double-pole triple-throw switch is a manual switch, which is easier to operate.

[0041] In some embodiments, the coil switching mechanism 6 may also be implemented by transformer tap connection.

[0042] In some embodiments, the positions of the first coil 1, the second coil 2, the third coil 3, the fourth coil 4 and the fifth coil 5 are fixed, and the stability is higher. Of course, in other embodiments, direct lead-out taps can also be used for wiring. This convenient structure is simpler, but switching between different working modes is not very convenient.

[0043] Another embodiment of the present application is to provide a metal detector, including a host computer 11 and the coil module as described above, wherein the host computer 11 is connected to each selection switch, wherein the host computer 11 can be a PC or some specially designed and customized embedded devices.

Claims

1. A multifunctional coil module for a metal detector, comprising a power driving circuit and a signal receiving circuit, characterized in that: It also includes a first coil, a second coil, a third coil, a fourth coil and a fifth coil, wherein the first coil, the second coil, the third coil, the fourth coil and the fifth coil are arranged in sequence, and the second coil and the fourth coil are at an equal distance from the third coil, and the first coil and the fifth coil are at an equal distance from the third coil, and the third coil is connected to the output end of the power driving circuit. The coil module also includes a coil switching mechanism, which includes a first selection switch, a second selection switch, a third selection switch and a fourth selection switch. The first selection switch, the second selection switch, the third selection switch and the fourth selection switch are all single-pole three-throw switches, and the common end is respectively connected to the first coil, the second coil, the fourth coil and the fifth coil, the first output end is connected to the power driving circuit, the second output end is empty, and the third output end is connected to the signal receiving circuit.

2. The multifunctional coil module of a metal detector according to claim 1, characterized in that: The single-pole triple-throw switch is a relay.

3. The multifunctional coil module of a metal detector according to claim 1, characterized in that: The single-pole triple-throw switch is a manual switch.

4. The multifunctional coil module of a metal detector according to claim 1, characterized in that: The positions of the first coil, the second coil, the third coil, the fourth coil and the fifth coil are fixed.

5. A multifunctional coil module for a metal detector, comprising a power driving circuit and a signal receiving circuit, characterized in that: It also includes a first coil, a second coil, a third coil, a fourth coil and a fifth coil, wherein the first coil, the second coil, the third coil, the fourth coil and the fifth coil are arranged in sequence, and the second coil and the fourth coil are at an equal distance from the third coil, and the first coil and the fifth coil are at an equal distance from the third coil, and the third coil is connected to the output end of the power driving circuit. The coil module further includes a coil switching mechanism, which includes a fifth selection switch and a sixth selection switch, wherein the fifth selection switch and the sixth selection switch are both double-pole triple-throw switches. The first common terminal of the fifth selection switch is connected to the first coil, the corresponding first output terminal is connected to the power driving circuit, the second output terminal is empty, and the third output terminal is connected to the signal receiving circuit. The second common terminal of the fifth selection switch is connected to the fifth coil, the corresponding first output terminal is connected to the power driving circuit, the second output terminal is empty, and the third output terminal is connected to the signal receiving circuit. The first common terminal of the sixth selection switch is connected to the second coil, the corresponding first output terminal is connected to the power driving circuit, the second output terminal is empty, and the third output terminal is connected to the signal receiving circuit. The second common terminal of the sixth selection switch is connected to the fourth coil, the corresponding first output terminal is connected to the power driving circuit, the second output terminal is empty, and the third output terminal is connected to the signal receiving circuit.

6. The multifunctional coil module of a metal detector according to claim 5, characterized in that: The double-pole triple-throw switch is a relay.

7. The multifunctional coil module of a metal detector according to claim 5, characterized in that: The double-pole triple-throw switch is a manual switch.

8. The multifunctional coil module of a metal detector according to claim 5, characterized in that: The positions of the first coil, the second coil, the third coil, the fourth coil and the fifth coil are fixed.

9. A metal detector, characterized in that: It comprises a host computer and a coil module as claimed in any one of claims 1 to 8, wherein the host computer is connected to each selection switch.

10. The metal detector according to claim 9, characterized in that: The host computer is a PC.

Images