Metal Detection Door with Foot Detection Enhanced Security

Abstract

The present invention relates to a detection using electromagnetic fields. A metal detection door with enhanced security inspection by foot detection includes a channel formed by a left door panel, a right door panel and a door head main control box. The left door panel and the right door panel are both provided with detection coils. The detection coils are composed of an external transmitting coil, an internal transmitting coil group, an internal receiving coil group, a foot detection coil, a seismic base and a pedal. The foot detection coil is installed on the seismic base, and the seismic base is fixed to the ground at the installation position; the pedal frame is buckled on the seismic base, and a gap is provided between the two, and they do not contact each other; the foot detection coil is provided with an even number of foot coil groups, and each foot coil group has at least one external transmitting coil, one internal transmitting coil and one receiving coil. The metal detection door of the present invention is provided with a foot security inspection device, and the foot coil group adjacent to the detection door has the same current direction, so that the magnetic field direction of the sole is the same, and the magnetic field strength is enhanced.

Description

Technical Field

[0001] The present invention relates to a detection using electromagnetic field, more specifically, the present invention relates to a metal detection door using an induction coil and having a foot detection enhanced security inspection device. Background Art

[0002] Metal detection doors, also known as metal security doors, are widely used in public places such as airports, stations, and customs. Metal detection doors are mainly used to detect whether the inspected person is carrying metal contraband, such as controlled knives, firearms, pressure gas cylinders, etc., which threaten public safety. Figure 3 As shown. Normally, the metal detection door is a channel-type structure metal detection door composed of left and right side panels and a door head main control box. Three groups of coils are installed inside the left and right door panels of the metal detection door, namely: a group of transmitting outer coils, a group of transmitting inner coils, and a group of receiving inner coils. Among them, the transmitting outer coil is wound along the inner side of the edge of the side panel, and one winding of the coil is installed in each of the left and right side panels. The transmitting inner coil group is provided with 1-8 small coils in total, each of which is wound on its own skeleton, arranged from top to bottom in the transmitting outer coil, and connected in series longitudinally. The number of small coils in the receiving inner coil group is the same as that of the transmitting inner coil group, and they are wound on the skeletons of their corresponding small coils of the transmitting inner coil, and the small coils of the receiving inner coil are connected in series with each other.

[0003] The working mechanism of the metal security door is: the control circuit loads a current signal with opposite phases to the transmitting outer coil and the transmitting inner coil group; wherein the transmitting outer coil generates an alternating magnetic field; at the same time, the transmitting inner coil group composed of 1-8 small coils generates an alternating magnetic field with opposite phases, and the two magnetic fields cancel each other out, so that the electromotive force of the receiving inner coil is zero. When a metal object passes through the doorway of the security door, the metal object is affected by the two alternating magnetic fields, and eddy currents are generated on the metal surface. The secondary field generated by the eddy currents generates an induced voltage in the receiving inner coil. According to this induced voltage, the control circuit can detect the presence of the metal object. The transmitting inner coil is set in multiples, and its purpose is to be able to detect the approximate position of the metal object in the channel more accurately.

[0004] The transmitting outer coil is wound into a rectangular multi-turn coil, and its size is a rectangular coil close to the height and depth of the channel side panel. The horizontal sides of the upper and lower ends of the rectangular coil are close to the top of the head and the bottom of the feet respectively; the straight sides of the rectangular coil are close to the vertical edges of the side door panel; so that the rectangular coil forms a sufficiently large detection area.

[0005] Thus, the current direction of the transmitting outer coil is as follows: Figure 1As shown in the figure: the arrows of a, b, c, d on the left door panel indicate the direction of the current; or the arrows of a', b', c', d' on the other door panel indicate the direction of the current. Since the magnetic fields generated by the currents a, b, c, d and a', b', c', d' have the same direction in the channel of the detection door, an approximately uniform electromagnetic field is generated on both sides of the entire detection channel.

[0006] First of all, the magnetic field generated by the currents c and c' is an inward-directed spiral magnetic field; however, since the coils are located on both sides of the door panel, the magnetic fields in the channel are in opposite directions, especially in the center of the channel, where the magnetic fields cancel each other out. Therefore, the magnetic field generated by the currents c and c' has no enhancing effect on the foot position in the center of the channel. In fact, the horizontal magnetic field generated by the currents a, b and a', b' still has a certain effect on the foot position. That is, under the combined action of the currents c and c', as well as a, b and a', b', there is also a certain detection effect, but its electromagnetic field is uneven relative to other positions. Therefore, the signal for detecting the foot is weak and difficult to detect.

[0007] Secondly, due to the structure of the door body, the coil cannot be close to the ground, but has a certain distance from the ground, resulting in the feet not being covered by the electromagnetic field of the coil, and the electromagnetic strength of the feet is relatively small.

[0008] Third, the magnetic field generated by the coil near the bottom is at the junction of the air medium and the earth (soil) medium. The inconsistency in the magnetic permeability of the two media leads to uneven distribution of electromagnetic density near the ground, causing the magnetic field strength of the feet to weaken.

[0009] In summary, the above factors lead to the weakening of the electromagnetic field of the metal detector door in the middle of the passage close to the ground. Specifically, when detecting metal objects on the soles of the feet and inner ankles, the eddy current signal generated becomes weaker, the detection effect is poor, and it is easy to miss reports.

[0010] In the prior art, in order to solve the problem of detecting metal on the feet, some people have specially designed independent sole metal detectors. The above design does not interfere with each other of the coils, and the structure is relatively simple. However, the security inspection process is relatively complicated. Usually, the security inspection process needs to be divided into two steps: first, pass the detection of the metal detection door; second, stand on the foot metal detection device to detect the metal under the feet. In other words, two security checks are carried out. The shortcomings of the existing security inspection facilities are: low security inspection efficiency, and it is very easy to cause blockage when there is a large flow of people. Summary of the invention

[0011] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a metal detection door that can be used for foot security inspection. The metal detection door is installed in the detection door and can detect the feet of the inspected person when the person passes normally without having to stop, thereby greatly improving the clearance speed.

[0012] The technical solution of the present invention is: a metal detection door with foot detection enhanced security inspection, including a channel formed by a left door panel, a right door panel and a door head main control box, the left door panel and the right door panel are both provided with detection coils, the detection coils are composed of an external transmitting coil, an internal transmitting coil group, and an internal receiving coil group, and the number of small coils of the internal transmitting coil group and the internal receiving coil group is equal to N; it is characterized in that: it also includes a foot detection coil, a seismic base and a pedal, the foot detection coil is installed on the seismic base, and the seismic base is fixed to the ground at the installation position; the pedal frame is buckled on the seismic base, and a gap is provided between the two, and they do not contact each other; the foot detection coil is provided with an even number of foot coil groups, each foot coil group includes an external transmitting coil, at least one internal transmitting coil and at least one receiving coil.

[0013] The number of small coils in the inner transmitting coil group and / or the inner receiving coil group is equal, which is N=1-8.

[0014] The foot coil groups are provided with 2, 4, 6 or 8 groups.

[0015] The distance between the edges of the bottom plate and the outer transmitting coil is 10-30 mm.

[0016] The current direction of the external transmitting coil on the left door panel is consistent with that of the external transmitting coil on the right door panel.

[0017] The current directions of the external transmitting coil on the left door panel and the foot coil group adjacent thereto are consistent; similarly, the current directions of the external transmitting coil on the right door panel and the foot coil group adjacent thereto are consistent.

[0018] The beneficial technical effect of the present invention is that the metal detection door of the foot detection enhanced security inspection device of the present invention is provided with a foot security inspection device, and the foot coil group adjacent to the detection door has the same current direction, so that the magnetic field direction of the sole is the same, and the magnetic field strength is enhanced. In this way, when the inspected person passes through, metal objects hidden in the soles and ankles will change the magnetic field of the foot coil group, causing the foot receiving coil to generate an induced voltage, which can be detected by the door head main control box. Since the metal detection door of the present invention is equipped with a foot detection transmitting coil, the inspected person can pass normally without other coordinated security inspections, so that the process that originally required two steps of detection is omitted, thereby improving the clearance speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of a metal detection door of the present invention;

[0020] Figure 2 It is a schematic diagram of the coil current direction of the metal detection door of the present invention;

[0021] Figure 3 yes Figure 1 A partial enlarged view of the foot detection;

[0022] Figure 4 yes Figure 3 Schematic diagram of the current direction of the foot coil. DETAILED DESCRIPTION

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0024] The metal detection door with foot detection enhanced security inspection device of the present invention is shown in the attached drawings for its specific embodiment. Figure 1-4 As shown. The metal detection door with foot detection enhanced security inspection device in this embodiment includes 5 parts, namely: left door panel 1, right door panel 2, door head main control box 3, anti-vibration base plate 4 and pedal 5. The anti-vibration base 4 and pedal 5 are installed under the passage of the metal detection door, and the pedal 5 is above the anti-vibration base 4, and there is a gap between the pedal 5 and the anti-vibration base, and they do not contact each other.

[0025] In this embodiment, the metal detection door with foot detection enhanced security inspection device of the present invention has four coil groups, namely: left door coil group 10, right door coil group 20, left foot coil group 41 and right foot coil group 42. Among them, the left foot coil 41 and the right foot coil 42 are on the anti-vibration base 4.

[0026] 1. About the coils of the left and right door side panels

[0027] The left door coil group 10 is composed of an outer transmitting coil 11, a group of inner transmitting coils 12, and a group of inner receiving coils 13.

[0028] The external transmitting coil 11 shown is installed on the inner side of the left door panel 1, and is composed of a multi-turn rectangular coil, whose size is slightly smaller than the height and depth of the passage side panel. The upper and lower ends of the rectangular coil are respectively close to the top and bottom of the side door panel; the two sides of the rectangular coil are close to the edge of the side door panel; so that the rectangular coil constitutes a sufficiently large detection area. The specific structure of this embodiment is: a rectangular groove is opened on the inner side of the left door panel 1, and a multi-turn coil is wound in the rectangular groove with copper wire to form a left coil group 10, and is fixed with epoxy resin.

[0029] Of course, it is not necessary to make rectangular grooves, and it is not necessary to make grooves. For example, winding directly on the door panel. In addition, the coil can be fixed without epoxy, and hot melt adhesive or other glue can be used to fix it.

[0030] The inner transmitting coil group 12 is usually composed of 1-8 small coils connected in series, in the same winding direction as the outer transmitting coil 11. In this embodiment, 6 small coils are connected in series. The more small coils there are, the more accurately the corresponding position of the metal object on the human body can be detected. The small coil can be wound on a coil frame, and then the coil frame is embedded in the corresponding groove; or the coil can be directly embedded in the groove. The current phase of the inner transmitting coil group 12 is opposite to that of the outer transmitting coil 11, so that the electromagnetic field of the entire left door is in a balanced state when no metal material enters.

[0031] The inner receiving coil group 13 has the same number of windings as the inner transmitting coil. In this embodiment, the inner receiving small coil is also composed of 6 independent small receiving coils. The inner receiving coil group 13 and the inner transmitting coil group 12 are wound together on a coil frame; or they are directly wound together and embedded in the groove.

[0032] The specific structure of the right door coil group 2 is the same as above, and is symmetrically arranged with the left door coil, and the current direction thereof is exactly the same.

[0033] 2. About the foot coil

[0034] The left foot coil group 41 is composed of an outer transmitting coil 411, an inner transmitting coil 412 and an inner receiving coil 413. The inner transmitting coil 412 and the inner receiving coil 413 are wound together on a coil frame, and the current phases of the outer transmitting coil 411 and the inner transmitting coil 412 are opposite.

[0035] Similarly, the right foot coil group 42 is composed of an outer transmitting coil 421, an inner transmitting coil 422 and an inner receiving coil 423. The inner transmitting coil 412 and the inner receiving coil 413 are wound together on a coil frame, and the current phases of the outer transmitting coil 421 and the inner transmitting coil 422 are opposite.

[0036] The left foot coil assembly 41 and the right foot coil assembly 42 are symmetrically arranged on the anti-vibration bottom plate 4 along the axis of the installation in and out direction.

[0037] 3. Current direction of the coils on both sides and the foot coil

[0038] 1) The current and direction of the left external transmitting coil 11 and the right external transmitting coil 21:

[0039] The left door 1 of the metal detection door of the present invention has a current direction of the outer transmitting coil 11, such as Figure 1 The current direction of the outer transmitting coil 21 of the right side plate 2 is shown as a, b, c, and d. Figure 1The current directions of the transmitting coil 11 and the external transmitting coil 21 are consistent, and the magnetic fields generated by the currents a, b, c, d and a', b', c', d' are consistent in direction within the channel of the detection door.

[0040] 2) The current and direction of the internal transmitting coil 12 of the left side plate 1 and the internal transmitting coil 22 of the right side plate 2:

[0041] In an embodiment of the present invention, the inner transmitting coil group (12 and 22) of the left side plate 1 (or the right side plate 2) is composed of six small coils connected in series, and the winding direction of each small coil is consistent with that of the outer transmitting coil (11 and 12). Figure 1 Middle: The current direction of the small coils a1, b1, c1, d1 of the left door (and the current direction of a2, b2, c2, d2-- a6, b6, c6, d6 not shown in the figure) is opposite to the current direction of the outer transmitting coil; the current direction of the inner transmitting coil of the right door is the same as above. In this way, the magnetic fields of the left plate (or right plate) are balanced.

[0042] 3) The left side plate (or right side plate) receives the induced current of coil 13:

[0043] When no metal object enters the passage of the security door, the currents of the outer transmitting coil 11 and the inner transmitting coil 12 are in opposite phases, and the directions of their magnetic fields are opposite. By adjusting the number of coil turns or the area, the magnetic fields of the two coils can cancel each other out in the receiving coil, so the electromotive force of the receiving coil 13 (or receiving coil 23) is 0.

[0044] 4) Current direction of the outer transmitting coil 411 (421) of the left foot coil (right foot coil)

[0045] In this embodiment, two sets of foot coil groups are used, and their structures are shown in FIG. Figure 1 As shown. The current direction of the outer transmitting coil 411 on the left side of the foot (the outer transmitting coil 421 on the right side of the foot) is e, f, g, h (e', f', g', h'), wherein the current direction h (h') is consistent with the current direction c (c') of the outer transmitting coil 11 of the left door, so the magnetic field generated by the current enhances the magnetic field of the entire detection door.

[0046] 5) Inner transmitting coil 412 (inner transmitting coil 422) of the left foot (right foot)

[0047] The current direction of the inner transmitting coil 412 of the left foot (the inner transmitting coil 422 of the left foot) is e1, f1, g1, h1 (e1', f1', g1', h1'), which is opposite to the current direction e, f, g, h (e', f', g', h') of the outer transmitting coil 411 (the outer transmitting coil 421).

[0048] 6) Inner receiving coil 413 (inner receiving coil 423) of the left foot (right foot)

[0049] When there is no metal object to be inspected and the foot enters the passage of the security door, the currents of the external transmitting coil 411 and the internal transmitting coil 412 of the left foot (right foot) are in opposite phases, and the directions of the magnetic fields of the two are opposite, canceling each other out; therefore, the induced electromotive force of the internal receiving coil 413 (423) of the left foot (right foot) is 0.

[0050] 4. Working principle of the metal detection door of the present invention in the detection state:

[0051] 1. Working principle of non-foot detection

[0052] The outer transmitting coil of the left (right) side door of the metal detection door of the present invention, the inner transmitting coil of the left (right) side door, and the receiving coil of the left (right) side door are electrically connected to the door head main control box.

[0053] When there is no metal object intrusion, the magnetic field generated by the current a, b, c, d of the outer transmitting coil 11 of the left (right) side plate and the magnetic field generated by the current d', c', b', a' of the six inner transmitting coils cancel each other out because their current phases are opposite, so the induced current of the six receiving coils is zero.

[0054] When a metal object invades, it is brought into the detection channel, and the balanced magnetic field generated in the transmitting coils on both sides is broken, which affects the induced potential change of the receiving coil in the receiving coil, thereby generating current. The main control box at the door head can detect the metal object and alarm.

[0055] 2. Working principle of foot detection

[0056] When no metal object enters with the foot, the magnetic field generated by the current e, f, g, h (h', g', f', e') of the outer transmitting coil 411 (421) of the foot and the magnetic field generated by the current e1, f1, g1, h1 (e1', f1', g1', h1') of the inner transmitting coil cancel each other out because their current phases are opposite. Therefore, the induced current of the receiving coil is zero.

[0057] When a metal object enters the passage of the security door through the foot, the magnetic field balance between the outer transmitting coil 411 and the inner transmitting coil 412 of the left foot (right foot) is destroyed. Therefore, an induced potential is generated in the inner receiving coil 413 (423) of the left foot (right foot), and the main control box of the door head can detect the presence of metal objects and alarm.

Claims

1. A metal detection door with enhanced security inspection for foot detection, comprising a channel formed by a left door panel, a right door panel and a door head main control box, wherein the left door panel and the right door panel are both provided with a detection coil, wherein the detection coil is composed of an outer transmitting coil, an inner transmitting coil group and an inner receiving coil group, wherein the number of small coils of the inner transmitting coil group and the inner receiving coil group is equal to N; characterized in that: It also includes a foot detection coil, a seismic base and a pedal, wherein the foot detection coil is installed on the seismic base, and the seismic base is fixed to the ground at the installation position; the pedal is buckled on the seismic base, and a gap is provided between the two, and they do not contact each other; the foot detection coil is provided with an even number of foot coil groups, and each foot coil group includes an outer transmitting coil, at least one inner transmitting coil and at least one receiving coil; The anti-vibration base and pedal are installed below the passage of the metal detection door; The number of the foot coil groups is 2, 4, 6 or 8; The distance between the edges of the anti-vibration base and the outer transmitting coil is 10-30 mm; The current directions of the external transmitting coil on the left door panel and the foot coil group adjacent thereto are consistent; the current directions of the external transmitting coil on the right door panel and the foot coil group adjacent thereto are consistent.

2. A metal detection door with enhanced security inspection by foot detection according to claim 1, characterized in that: The number of small coils in the inner transmitting coil group and / or the inner receiving coil group is equal, which is N=1-8.

3. A metal detection door with enhanced security inspection by foot detection according to claim 2, characterized in that: The number of small coils N=6.

4. A metal detection door with enhanced security inspection by foot detection according to claim 1, characterized in that: The current direction of the external transmitting coil on the left door panel is consistent with that of the external transmitting coil on the right door panel.

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