JP2002156462A - Metal detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the accuracy of a metal detection in a metal detecting apparatus which detects the inclusion of a metal by using a coil while a specimen is being passed from the upper part to the lower part. SOLUTION: The metal detecting apparatus 50 is an apparatus which detects the inclusion of the metal while the specimen is being passed. The apparatus is provided with coils 52, 53, 54 and a tube 56. The specimen passes hollow parts in the coils 52, 53, 54 from the upper part to the lower part. The tube 56 regulates the passage region of the specimen in such a way that the specimen does not pass the vertical axis 0 including the center of the hollow parts in the coils 52, 53, 54 and a region near the vertical axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal detecting device, and more particularly to a metal detecting device for detecting the intrusion of metal while passing a test object from above to below.

[0002]

2. Description of the Related Art In a production line for foods, cosmetics, medicines, and the like, a metal detection device is used to check whether a metal piece is present in a product or mixed with the product. In this metal detection device, an object to be inspected is passed through a magnetic field generated by a coil, and the presence or absence of metal in the object to be inspected is inspected based on a change in a magnetic field generated by a metal piece.

[0003]

This type of metal detection apparatus is also used for a metal detection process for a falling inspection object. Here, a plurality of coils for generating a magnetic field and detecting a magnetic field fluctuation are arranged vertically, the hollow portions of these coils are aligned with the pass band of the object to be inspected, and the coils falling through the hollow portions of the coils are dropped. Inspect the inspection object for metal contamination.

In such a metal detecting device, it is required to improve the metal detecting accuracy. In particular, in the case of a metal detection device that targets an object falling from above, it is often not determined which area of the hollow portion of the coil the object to be inspected passes. It is difficult to accurately detect changes in the magnetic field due to metal because of the tendency to randomly pass through various parts of the part.

SUMMARY OF THE INVENTION An object of the present invention is to improve the accuracy of metal detection in a metal detection device that detects the intrusion of metal by using a coil while passing the object to be inspected from above to below.

[0006]

According to a first aspect of the present invention, there is provided a metal detecting apparatus for detecting the intrusion of a metal while passing an object to be inspected, and includes a coil and a regulating member. The test object passes through the hollow portion of the coil from above to below. The restricting member is provided on the inspection object so that the inspection object does not pass through the vertical axis including the center of the hollow portion of the coil and a region in the vicinity thereof (hereinafter, referred to as a region near the center vertical axis of the coil hollow portion). Regulate the pass area.

In this case, since the metal detecting device is provided with the regulating member, the object to be inspected does not pass through the region near the center vertical axis of the hollow portion of the coil, or becomes less. The area near the center vertical axis of the coil hollow area is the area where the detection sensitivity is the lowest in a metal detection device of the type that performs metal detection using a coil, so that only the other area is covered without passing through this area. If the inspection object passes, the metal detection accuracy of the metal detection device is improved. As a result of an actual test, a metal piece that could not be detected without a regulating member was detectable with a metal member provided with the regulating member.

As described above, since the regulating member is provided so that the inspection object does not pass through the vicinity of the center vertical axis of the hollow portion of the coil, the accuracy of metal detection is improved. A metal detecting device according to a second aspect is the metal detecting device according to the first aspect, wherein the regulating member extends along the vertical axis near the center of the hollow portion of the coil.

Here, since the regulating member actually occupies the space near the center of the hollow portion of the coil, the inspection object can be more reliably prevented from entering the region near the center vertical axis of the hollow portion of the coil. A metal detecting device according to a third aspect is the metal detecting device according to the second aspect, wherein the regulating member extends to above the hollow portion of the coil.

[0010] Here, the restricting member does not stay inside the hollow portion of the coil but extends above the hollow portion of the coil. Therefore, even when the inspection object enters the metal detector with a force component (vector) other than vertically downward, the upper part of the regulating member guides the inspection object along the vertical direction. In addition, the uniformity of the passing direction when the inspection object passes through the hollow portion of the coil is improved.

In addition, even when the regulating member does not exist in the space below the hollow portion of the coil, the regulating member guides the direction of the passage of the inspection object above and above the hollow portion of the coil, and Is prevented from entering and passing near the center of the lower space of the hollow portion of the coil. That is,
Intrusion of the test object into the vicinity of the center vertical axis of the coil hollow portion is further reliably suppressed.

According to a fourth aspect of the present invention, there is provided a metal detecting device.
4. The metal detection device according to any one of items 1 to 3, wherein the regulating member is formed of a flexible nonmetallic material. If metal parts are always present inside the detection coil,
The possibility that erroneous detection will occur due to the vibration or movement of the component increases. On the other hand, since the regulating member is formed from a nonmetallic material, occurrence of erroneous detection can be suppressed.

Further, since the regulating member has flexibility, an impact when the inspection object collides with the regulating member is suppressed, and damage and breakage of the inspection object are suppressed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Outline of Production Line Using Metal Detector 50> FIG. 1 shows a part of a food production line using a metal detector according to an embodiment of the present invention. Some of the production lines include confectionery, fruits and vegetables, side dishes,
Goods such as dried noodles and processed foods are bagged by a predetermined weight (or a predetermined quantity).

[Previous Step of Metal Detector 50]
Goods are first conveyed above the combination weighing device 10 by the supply conveyor device 90. Next, the articles are placed on the dispersion feeder 11 and are radially dispersed by the vibration of the dispersion feeder 11. Then, when the products are sent to a plurality of pool hoppers 13 arranged circumferentially via a radiation trough 12 following the dispersion feeder 11, the products are temporarily pooled there, and then the products are positioned below each pool hopper 13. Into the measuring hopper 14. The weight of the product put into the weighing hopper 14 is measured by a load cell (weight detector) provided for each weighing hopper 14. Then, based on the measured weight of the product in each weighing hopper 14, a combination operation is performed to determine which weighing hopper 14 from which the product should be discharged to obtain a weight or quantity within an allowable range. The product discharges the goods to the collective discharge chute 15 (see FIG. 2).

Collective discharge chute 1 of combination weighing device 10
The product discharged from 5 passes through the metal detection device 50 disposed below, and further falls to the bag making and packaging device 20 disposed below. The metal detection device 50 will be described later in detail.

The dispersion feeder 11 and the radiation trough 1
2. The pool hopper 13 and the weighing hopper 14 are supported by a main body support 17 attached to a main body case 16. The collective discharge chute 15 is also supported by the main body support 17.

[Post-Process of Metal Detecting Apparatus 50] The bag making and packaging apparatus 20 is an apparatus that fills and packs a product into a bag while manufacturing the bag. The bag making and packaging apparatus 20 is called a vertical pillow packaging machine. First, a sheet-like film drawn from a film roll 128 is formed into a cylindrical shape by a former and a tube. Is heat-sealed (heat-sealed). When the dropped product is filled in the tubular film, the horizontal sealing mechanism disposed at the lower portion performs the horizontal sealing over the upper portion of the preceding bag and the lower portion of the subsequent bag, and the horizontal sealing portion is provided. Is cut by the cutter at the center.

The bag filled with the product is placed on the inclined plate 2.
9 and is transferred to the weight checker 40 at the subsequent stage by being placed on the conveyor 30. <Configuration of Metal Detecting Device 50> The metal detecting device 50 receives a product falling from the collecting / discharging chute 15 of the combination weighing device 10 disposed above, and forms a metal piece while passing the product downward. Detect contamination. As shown in FIG. 3, the metal detection device 50 mainly includes a detection head 51, a cylindrical member 55, a tube 56, and a jaw 58. These metal detectors 5
0 are fixed to a gantry 80 supporting the combination weighing device 10 and the bag making and packaging device 20 by a support member (not shown).

[Detection Head 51] The detection head 51 is covered by a casing having an outer shape such that a columnar space penetrating vertically is formed in the center of a rectangular parallelepiped, and three coils 52, 53 and 54 are arranged. The coil 53 is a transmission coil that generates an AC magnetic field based on an AC signal from an oscillator (not shown). The coils 52 and 54 are reception coils wound coaxially with the transmission coil 53, and are arranged so that their magnetic fluxes interlink equally.

[Cylindrical Member 55] The cylindrical member 55 is a member made of vinyl that extends in the vertical direction, and is disposed so as to penetrate the cylindrical internal space of the detection head 51. The internal space of the cylindrical member 55 serves as a path for commodities. The upper end of the cylindrical member 55 covers the outer periphery of the lower part of the jaw 58, and a stop band 57 (described later) is attached from above. That is, the upper end of the cylindrical member 55 is sandwiched between the jaw 58 and the stop band 57. Then, with the upper end fixed as described above, the cylindrical member 55 is hung downward.

[Tube 56] The tube 56 is made of vinyl, and has an outer diameter that is considerably smaller than the inner diameter of the cylindrical member 55, as shown in FIG. The height position of the lower end of the tube 56 substantially coincides with the lower surface position of the detection head 51. The tube 56 extends vertically to a position much higher than the height position of the upper surface of the detection head 51 (see FIG. 3A), and its upper end is located in the internal space of the jaw 58.

The center of the tube 56 is supported by the coils 52, 53,
It is held so as to substantially coincide with the vertical axis O including the center of the hollow portion (the axis of the coil). The end of the support bar 59 is fixed to the lower inner wall of the jaw 58. The outer periphery of the support rod 59 is covered with a vinyl coating.

[Jogo 58] The jago 58 is made of metal, and has a structure in which the upper portion has a larger opening area than the lower portion. The opening shape of the lower part of the jaw 58 is
The shape substantially matches the shape of the upper opening of the cylindrical member 55. The product that has fallen from the collecting / discharging chute 15 of the combination weighing device 10 first enters the jaw 58 and then enters the cylindrical member 5.
5 and falls into the lower bag making and packaging apparatus 20.

<Operation of Metal Detector 50> In the metal detector 50, an AC signal is oscillated by an oscillator,
3 generates an AC magnetic field of a predetermined frequency. Receiving coils 52 and 5 receiving an alternating magnetic field by transmitting coil 53
The electromotive forces generated in 4 are adjusted to be equal to each other in the initial setting.

When the metal pieces pass through the hollow portions of these coils 52, 53, 54, that is, when the metal pieces pass through the cylindrical member 55 from top to bottom while being mixed with the product, the receiving coil 52 and the receiving coil 54 There is a difference in the electromotive force generated in the. The metal detection device 50 detects this electromotive force difference using an amplifier or a detection circuit, and when the electromotive force difference is equal to or more than a predetermined level, determines that a metal piece has been detected and issues a metal detection signal.

<Features of Metal Detector 50> (1) Here, since the tube 56 is provided at the center of the metal detector 50, the product to be inspected is the coil 5
There is no need to pass through the vicinity of the center of the hollow portion of 2, 53, 54. As described above, the tube 56 is arranged in the above-described region where the detection sensitivity is lowest in a metal detection device of a type that performs metal detection using a coil, and a mistake in metal detection due to a metal piece passing through the region is suppressed. Therefore, metal detection accuracy is improved.

When a test was conducted in which a fine wire piece was actually passed through 120 times, a detection error (non-detection) occurred at a rate of 30% when the tube 56 was not mounted. In the metal detection device 50 provided with 56, the ratio of detection errors was 0.

(2) Here, the tube 56 extends not only inside the detection head 51 but also inside the jaw 58 above it. For this reason, for a product that enters the jago 58 with a force component (vector) other than the vertically downward direction from the collecting and discharging chute 15 of the combination weighing device 10, the force component other than the vertically downward direction is cut to some extent by the tube 56. . This improves the uniformity of the product passing direction (direction close to the vertical downward direction) when the product passes through the height position of the detection head 51, and improves the stability of metal detection accuracy.

(3) Here, the cylindrical member 55 and the tube 56 are made of vinyl, so that the impact when a product collides with them can be suppressed. Further, the outer periphery of the support rod 59 is also covered with a vinyl coating. Thereby, damage and breakage of the product are reduced.

In particular, here, as shown in FIG. 2, the products collected from each weighing hopper 14 by the collecting and discharging chute 15 have a horizontal force component in addition to the vertically downward force component. Therefore, a product entering the metal detection device 50 has a high probability of colliding with the tube 56 or the cylindrical member 55. However, since the two members 55 and 56 are made of vinyl and have flexibility as described above, damage and breakage of the product can be suppressed.

[Other Embodiments] (A) In the above embodiment, the tube 56 extends down to the lower surface position of the detection head 51, but does not necessarily have to extend to the lower surface position of the detection head 51.

For example, even if the lower end of the tube 56 extends only to the middle or upper end of the detection head 51, the product guided by the upper portion of the tube 56 passes almost vertically downward at the height of the detection head 51. In such a case, there is almost no possibility that a product including a metal piece enters the vicinity of the vertical axis O in the hollow portion of the detection head 51, and the possibility of occurrence of a metal piece detection error is extremely small. In such a case, the tube 56 does not need to extend to the lower surface position of the detection head 51.

(B) In the above embodiment, the tube 56 extends to the inner space of the jaw 58, but occupies the center of the hollow portion (coil axis) of each of the coils 52, 53, 54 of the detection head 51. If the tube 56 is present, the tube 56 does not necessarily need to extend into the jaw 58.

(C) In the above embodiment, the tube 56 is held by the support rod 59, but the upper end of the tube 56 is supported by the lower part of the main body case 16 of the combination weighing device 10 without using the support rod 59. , Detection head 5 from there
It is also possible to adopt a configuration in which the tube 56 hangs down to one.

(D) In the above embodiment, three coils 5
2, 53 and 54 are shown in FIG. 3 as an example in which the present invention is applied to a metal detection device arranged coaxially in the casing of the detection head 51.
2 and 45 are arranged in the same plane, and each coil 52, 53, 5
The present invention can also be applied to a metal detection device of a type in which 4 is disposed on a plane parallel to the passing direction of the product. Also in the case where the present invention is applied to such a parallel arrangement type metal detection device, the metal detection accuracy is improved as in the case where the invention is applied to the coaxial arrangement type metal detection device as in the above embodiment.

[0037]

According to the present invention, since the regulating member is provided in the metal detecting device, the object to be inspected does not pass through the region near the center vertical axis of the hollow portion of the coil. In other words, the object to be inspected must pass only the other area without passing through the area near the center vertical axis of the hollow part of the coil where the detection sensitivity is the lowest in a metal detection device that performs metal detection using a coil. become. For this reason, the accuracy of metal detection is improved.

[Brief description of the drawings]

FIG. 1 is a side view of a part of a food production line in which a metal detection device according to one embodiment of the present invention is used.

FIG. 2 is a diagram illustrating a state of a product discharged from a combination weighing device to a metal detection device.

FIG. 3A is a side view of a metal detection device. (B) The bb arrow view.

[Explanation of symbols]

 Reference Signs List 50 metal detection device 51 detection head 52, 53, 54 coil 55 cylindrical member 56 tube (restriction member) 59 support rod O vertical axis

Claims (4)

[Claims] 1. A metal detecting device for detecting mixing of metal while passing an object to be inspected, comprising: a coil having a hollow portion through which an object to be inspected passes from above to below; and a center of the hollow portion of the coil. A metal detection device, comprising: a regulating member that regulates a passing area of the object to be inspected so that the object does not pass through the vertical axis including the vertical axis and a region near the vertical axis. 2. The regulating member extends along the vertical axis near a center of a hollow portion of the coil.
The metal detection device according to claim 1. 3. The metal detecting device according to claim 2, wherein said regulating member extends to above a hollow portion of said coil. 4. The metal detecting device according to claim 1, wherein said regulating member is formed of a non-metallic material having flexibility.