JPH0972885A - Metal detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly prevent an object to be inspected mixed with metal foreign matter from flowing to other processing process by a detection leak by making the transfer to detection operation impossible unless a detection capacity confirming test is performed. SOLUTION: When the power supply of a metal detection means (means 32) is turned ON, a control means 45 can preferentially enter a test mode according to an operation program. Then, a feed means (means 25) is operated to feed a test piece to the means 32 to detect the metal sphere of the test piece. When the detection of the metal sphere is judged by a judge means 40, the means 45 completes the test mode in such a state that the means 25 is operated as it is to change over the test mode to a usual detection mode to enable the detection operation of the object to be inspected. When the metal sphere is judged to be not detected by the means 40, if 30sec is not elapsed after the operation of the means 25 is started, the test piece is re-detected. If 30sec is elapsed, the means 45 turns the power supply of the means 25 OFF on the basis of the signal of 'test not executed yet' or 'test failure' of the means 40 to prevent detection operation in such a state that the means 32 is not normal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for inspecting and detecting the presence / absence of metallic foreign substances that should not be mixed in all non-metallic products such as agricultural and marine products, other foods, clothing and industrial materials. And a metal detection device.

[0002]

2. Description of the Related Art As a conventional metal detecting device, there is one shown in FIG. 8, for example. The metal detection device shown in the drawing has an upstream side (lower right side in the figure) on a conveyor belt 28 driven to be fed in the direction of arrow B via a driven wheel 26 which is driven by a motor 25 and rotates in the direction of arrow A. ), The loaf bread 1 is placed as a subject on the loaf bread, and the loaf bread 1 is conveyed by the conveyor belt 28 in the direction of the arrow B, and magnetically inspected for the presence of foreign metal such as nails or screws during the conveyance. It has become.

Above the main body 31 of the metal detector, a search coil is built in and a rectangular tunnel passage 32 is provided.
a casing 32 with a built-in coil having a is provided, and the loaf bread 1 has a tunnel passage 32a of the casing 32 with a built-in coil.
When passing through, the search coil in the coil built-in casing 32 magnetically detects foreign matter such as nails and screws mixed in the loaf bread 1.

Reference numeral 34 is an operation control device for operating the metal detecting device by the user operating it, or controlling the operation of each part of the metal detecting device. The operation control device 34 has a data display section, operation buttons, and the like on the outside, and various electric circuits, wiring furnaces, and other electric parts on the inside.

Inside the coil built-in casing 32, FIG.
The search coil 100 as shown in FIG.
And a receiving coil 201, and is connected to other parts such as the excitation unit 101 and the low-frequency amplification unit 202 to form a metal detection circuit. Excitation coil 1
03 and the receiving coil 201 are arranged so that the conveyor belt 28 on which the loaf bread 1 of FIG.

The excitation coil 103 is adapted to generate a DC magnetic field by the DC current from the excitation unit 101,
A current is induced in the receiving coil 201 by the DC magnetic field of the excitation coil 103. The receiving coil 201 is composed of two receiving coils 201a and 201b in order to improve the resistance to disturbance, and is configured to be differentially connected to each other.

In FIG. 8, when the loaf bread 1 advances in the B direction,
The loaf bread 1 that has approached the receiving coil 201 in the coil built-in casing 32 first passes near the receiving coil 201a, and then the loaf bread 1 separates from the receiving coil 201a and then passes near the receiving coil 201b, and then the loaf bread 1 The receiving coils 201a and 201b are arranged in such a direction as to move away from the receiving coil 201.

By the way, the metallic foreign matter mixed in the loaf bread 1 is weak but has magnetism and conductivity and has a property of affecting the magnetic field. Because of not having such a property, the foreign metal and the bread 1 generally have greatly different influences on the magnetic field.

Therefore, the metallic foreign matter mixed in the loaf bread 1 is conveyed to the conveyor belt 28 and moved, so that the receiving coil 2 by the magnetic field of the exciting coil 103 first.
The interlinkage magnetic flux of 01a is changed, and a voltage is induced between the receiving coils 201a and 201b whose voltage was zero until then.

Next, the loaf bread 1 moves and the receiving coil 20 moves.
As it moves away from 1a and approaches the receiving coil 201b,
This time, the receiving coil 201 by the magnetic field of the excitation coil 103
By changing the interlinkage magnetic flux of b, the voltage is induced again between the receiving coils 201a and 201b with the time difference due to the moving speed of the loaf bread 1 from the induction of the voltage similar to the above.

Such receiving coils 201a and 201b
The induced voltage output from the interval is amplified by the low-frequency amplification unit 202, and after removing excess noise through the filter 204, it is compared with the reference value by the comparison unit 203 and a detection voltage corresponding to the difference is output. To be done.

In such a conventional example, the excitation unit 101
Has described the case where a DC magnetic field is generated by supplying a DC current to the excitation coil 103. Instead of generating the DC magnetic field in this way, the excitation unit 101
The same purpose can be achieved by replacing the exciting coil 103 with a permanent magnet. In addition to this, an AC magnetic field type metal detection device can be configured by using an AC current for the excitation unit 101 and the excitation coil 103, and installing a detection unit after the receiving coils 201a and 201b.

Further, in the conventional metal detecting device as in the conventional example, a conveyor belt is generally used as a conveying means for conveying an object to be inspected for contamination of metal foreign matter. Can be said. However, some have other types of transport means, or some do not have transport means as described below.

[0014]

In such a conventional metal detecting device, in recent years, there is a tendency that high sensitivity is required for the detection ability, and the sensitivity is deviated from the set value due to various reasons. Occasionally, abilities do not work properly. Therefore, if you start using the metal detection device after not using it for a long time, or if you place special importance on reliability in detecting foreign metal inclusions, be sure to insert a metal ball before starting use. The test piece is passed through the tunnel passage 32a of the casing 32 with a built-in coil several times to test whether or not the detection capability of the metal detection device is normal, and then the normal metal detection operation is started.

As shown in FIG. 10, the test piece has a length L of 50 mm, a width W of 30 mm, and a thickness H of about 5 mm. The sphere 15 is embedded.

A chip (10) of the test piece is conveyed in the forward direction by a conveyor belt (28) on which the chip (10) is mounted, and a photoelectric tube (not shown) is provided at a position before entering the tunnel passage (32a) of the coil built-in casing (32). The plastic chip 10 forming the test piece is detected by the photoelectric tube, passes through it, and enters the tunnel passage 32a.

In the above test, the chip 10 of the test piece was detected by the photoelectric tube, and the search coil 1 was used.
00 outputs a detection voltage that is equal to or larger than a reference value set in advance according to the size of the metal ball 15 embedded in the test piece, and satisfies both conditions.

The reason why the chip 10 of the test piece is detected by the photoelectric tube is that the test piece is the tunnel passage 32a.
Even if it does not pass through the inside, the metal detection device may malfunction and output the detection voltage due to vibration or other disturbances.To prevent the result of such malfunction, the number of times the test piece is detected is counted. This is because

However, depending on the work site or the user, the metal detecting device is suddenly used for a normal detecting operation for the object without performing such a test, and the detecting operation is performed while the detecting ability of the metal detecting device is not normal. Therefore, there were cases in which there was a case in which a metal foreign object was not detected.

In view of the above problems, the metal detecting apparatus according to the present invention is designed so that the normal metal detecting operation cannot be performed without a test for confirming that the detection ability is normal. Therefore, it is an object of the present invention to provide a metal detection device capable of reliably preventing an object, in which a metallic foreign matter is mixed due to a detection omission, from flowing to another product processing step.

[0021]

In order to solve the above-mentioned problems, a metal detecting apparatus according to the present invention is a metal detecting device which has a conveying path for conveying an object to which a foreign metal may be mixed, and the conveying path. Before performing the detection operation on the object, the metal detection means having a detection part that is provided on the way and magnetically detects the presence or absence of a metallic foreign matter that may be mixed in the object, and the metal detection means performs the detection operation on the object. A test piece for detecting the test piece, to determine whether or not a test of whether the metal detection means operates normally, and to determine whether the test has passed or failed; If the test is passed, the metal detection means is allowed to perform the detection operation on the subject, and if the test is not performed or the test fails, the carrying Is obtained by a configuration in which a control means for stopping the conveying operation of the unit.

According to the metal detecting device having such a structure,
Before the metal detection means performs the detection operation of the metallic foreign matter on the subject, a test is performed as to whether or not the metal detection means operates normally, and if this test is passed, the control means controls the metal detection means on the subject. When the test is not performed or the test fails, the control means stops the carrying operation of the carrying means, so that the detection capability of the metal detecting means is improved. It is possible to reliably prevent the detection operation of the metallic foreign matter for the specimen in an abnormal state, and to prevent the specimen containing the metallic foreign matter due to the detection omission from flowing to other product processing steps. You can

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing a metal detection device according to a first embodiment of the present invention.
Since the metal detecting device according to the first embodiment has all the configurations and operations of the metal detecting device according to the conventional example, duplicate description will be omitted and only different parts will be described.

FIG. 1 is a block diagram showing the functional structure of a metal detection device. In the figure, reference numeral 40 is metal detecting means (casing 32 with built-in coil, search coil 10).
0, excitation unit 101, low frequency amplification unit 202, comparison unit 20
3, the filter 204 and the like), and the transport means (the belt conveyor including the motor 25, the driven wheel 26, the conveyor belt 28, etc.) starts to operate,
The determination means is for determining whether or not a test has been performed to determine whether or not the metal detection means operates normally, and when the test is performed, whether the result is a pass or a failure.

The discriminating means 40 is constructed so as not to output a signal, for example, when the test is not conducted, and to output a High signal when the test is conducted and passes, and a Low signal when the test is unsuccessful. ing.

Reference numeral 45 enables, based on the signal from the discriminating means 40, the operation of detecting the metallic foreign matter in the object by the metal detecting means, or stopping the operation of the conveying means so that the detecting operation cannot be performed. It is a control means for performing a control operation such as turning on and off.

In addition to the above, a counter 48 for measuring the number of tests, a warning means 50 using an auditory audible sound to give a warning operation by a signal from the control means 45, and a warning operation with a visible electric light display. A warning means 51 using visual sense is provided.

The discriminating means 40 and the control means 45 are, as required,
It is connected to the comparison unit 203 connected to the search coil 100 in the coil built-in casing 32, the motor 25 of the belt conveyor (conveying means), their power supply switch unit, or the photoelectric tube and the like, and is constituted by an appropriate electric circuit. And is arranged inside the operation control device 34, for example.

The counter 48 is connected to the discrimination means 40 and the control means 45, the warning means 50 and 51 are connected to the control means 45, and the counter 48 is connected to the discrimination means 40 and the control means 4.
5, the warning means 50 and 51 are also arranged outside the operation control device 34, although they are also arranged inside the operation control device 34.

FIG. 2 is a flow chart showing an operation procedure in the case where the metal detection device according to the first embodiment described above mainly performs a test as to whether or not the metal detection means normally operates (test mode). The operation in the test mode is always performed with the highest priority when the metal detection device is started by turning on the power, and the normal detection operation for the object cannot be performed unless the operation in the test mode is completed. It is like this.

Below, based on the flowchart of FIG.
The operation of the metal detection device according to the first embodiment in the test mode will be described.

In this test mode, first, when the power source of the metal detection means is turned on, the operation program of the control means 45 preferentially enters the test mode (step S
1), the count value of the counter 48 for measuring the number of tests is reset to "0" (step S2). Next, when the power supply of the conveying means is turned on (the start switch of the belt conveyor is operated) (step S3), the driving operation of the belt conveyor is started (started) (step S4).

At this time, at the same time, the warning means 50 issues a warning by an audible voice (for example, an intermittent sound) that the test mode is currently in progress, and the warning means 51 gives a warning by a visual electronic display (for example, "test piece transport"). “Middle” is displayed) to alert the user not to perform the normal detection operation for the subject (step S5).

Next, when the test piece is conveyed onto the belt conveyor (step S6), the passage of the test piece is confirmed by the photoelectric tube installed in front of the coil built-in casing 32 containing the search coil 100 (step S7). . When the test piece passes through the coil-embedded casing 32, the determination means 40 determines whether a metal ball in the test piece is detected (step S8).

When the metal ball in the test piece is not detected (NO in step S8), it is measured by the built-in timer whether 30 seconds have elapsed from step S3 when the power of the belt conveyor is turned on (step S9), Thirty
In the case of NO where seconds have not elapsed, the process returns to step S6.

In step S8 again, the discrimination means 40
When it is determined that the detection of the metal ball in the test piece is performed (YES), "1" is added to the count value of the counter 48 (step S10), and it is further determined whether this is the predetermined number of times N times. (Step S1
1).

If YES in step S11, the control means 45 turns off the sound warning operation by the warning means 50 and the electric light display by the warning means 51 by the signals from the discrimination means 40 and the counter 48 (step S12). . Further, the control means 45 ends the test mode without turning off the power of the belt conveyor and switches the program to the normal detection mode (step S1).
3) After that, the metal detection means can perform the operation of detecting the metallic foreign matter in the subject.

If it is determined in step S11 that N times have not been detected (NO), it is measured in step S9 whether 30 seconds have elapsed from step S3 when the power of the belt conveyor was turned on.

When it is measured in step S9 that 30 seconds have elapsed (YES), the control means 45 sends a signal from the discrimination means 40, which indicates "the test has not been performed" or "the test has failed". Signal to the belt conveyor to turn on the power of the belt conveyor motor 25.
The driving operation is stopped by performing the FF (step S14), and it is possible to prevent the metal foreign matter detection operation from being performed on the subject while the metal detection means is not normally performing the detection operation. Then, it becomes "RETURN" and prepares for the next power-on (step S15).

If YES in step S11,
When the metal detecting means can detect the metallic foreign matter in the object, the control means 45 terminates the test mode program and switches to the normal program as described above (step S13).

As a result, in the test mode, when both the conditions that the chip 10 of the test piece is detected by the photoelectric tube and that the search coil 100 outputs the detection voltage above the reference value are satisfied, While the operation of the belt conveyor is not stopped after passing the test, in the operation of the normal program, contrary to the test mode, the photoelectric tube detects the object and the search coil 100 is equal to or more than the reference value. Of the detection voltage being output,
When both conditions are satisfied, it means that the metallic foreign matter is detected, and in that case, the control means 45 turns off the power of the motor 25 of the belt conveyor to stop the conveyor operation, and the user removes the metallic foreign matter. To be able to do.

As described above, in the metal detecting device according to the first embodiment, when the belt conveyor start switch is operated (power is turned on) to start the operation of the belt conveyor, the 30-second timer starts and within 30 seconds. If the test is not completed, the driving of the conveyor belt 28 is automatically stopped. By doing so, it is possible to reliably prevent the possibility that the metal detection device may fail to detect the foreign metal.

When stopping the metal detecting device, the belt conveyor stop switch provided next to the belt conveyor start switch is operated to turn off the power of the belt conveyor (step S16). Therefore, the driving operation of the belt conveyor is stopped (step S1).
7), thereby becoming "RETURN" and preparing for the next power-on (step S18).

FIG. 3 is a block diagram showing the functional structure of a metal detection device according to the second embodiment of the present invention.
As shown in the figure, the metal detection apparatus according to the second embodiment has almost the same functional configuration as that of the first embodiment, but a signal from the control means 45 conveys the conveyance means. The difference is that a reversing means 53 for reversing the direction is provided.

That is, in the second embodiment, when the test piece is conveyed onto the belt conveyor, the belt conveyor reverses and stops at the conveyance start position after the test of the test piece is detected. Therefore, even if the user mistakenly conveys the subject (product) during the operation period of the test mode, the subject is not transported to the next step because the subject returns to the start position.

FIG. 4 is a flow chart showing an operation procedure in the case where the metal detection device according to the second embodiment carries out a test for whether the metal detection means normally operates (test mode). The operation in the test mode in the metal detection device according to the second embodiment will be described based on the flowchart of FIG.

First, when the power of the metal detection device is turned on,
Here, as in the first embodiment, the test mode is preferentially entered (step S1), and then in step S2,
The count value of the counter 48 for measuring the number of tests is set to "0". Next, in step S3, the conveyor activation switch for activating the conveyor belt 28 is operated to turn on the power of the belt conveyor, thereby causing the conveyor belt 28 to be conveyed in the forward direction (step S4).

Next, a test piece (a plastic chip 10 having metal balls embedded therein) is placed on the conveyor belt 28.
Are placed and transported (step S5). Next, it is determined whether or not the photoelectric tube provided in front of the coil built-in casing 32 has detected the test piece (step S6). If YES, the search coil 10 in the coil built-in casing 32 is determined.
The metal detection means including 0 performs the detection operation for the test piece, and whether the detection voltage by the search coil 100 is larger than a value obtained by subtracting 20% from a predetermined reference value corresponding to the size of the metal ball in the test piece. Is determined (step S7).

If YES in step S7, the belt conveyor is once stopped and then reversed (step S8), and the conveyor belt 28 is stopped when the test piece reaches the original start position (step S9). At this time, 1 is added to the count value "0" of the counter 48 to make it "1" (step S10).

Next, the control means 45 determines whether the test has been performed N times by the signal from the counter 48 (step S11). If NO, the process returns to step S4 and the subsequent steps are performed as described above. repeat. When this is repeated N times and YES is determined in step S11, the control means 45 terminates the program in the test mode without switching off the power source and switches to the normal program (step S12) to detect the metal. It becomes possible for the means to perform the operation of detecting the metallic foreign matter with respect to the subject.

In step S7, the detected voltage is 20% from the reference value corresponding to the size of the metal ball in the test piece.
When it is smaller than the minus value (NO), the conveyor belt 28 is reversed in the same manner as in steps S8 and S9, and the conveyor belt 28 is stopped at the position where the original start position is reached (steps S13 and S14).

Then, the control means 45 which has received the signal indicating the failure of the test from the discrimination means 40 has the warning means 50, 51.
To the warning means 50 to turn on the buzzer for notifying the abnormality, and the warning means 51 also performs an electronic display to indicate the abnormality (step S15), and turns off the power supply of the conveying means and the metal detecting means (step S16). ).

As a result, it is possible to prevent the detection of the metallic foreign matter in the object under the condition that the detecting ability of the metallic detecting means is not normal, and to reliably prevent the detection failure of the metallic foreign matter. After that, the cause of abnormal detection ability is removed by repairing, the power is turned on again, and each operation is performed again in the order of each step described above (R
ETURN).

The metal detecting apparatus according to the second embodiment as described above is used for the test so that the test piece placed on the conveyor belt 28 for the test does not flow to other manufacturing processes. Immediately after the detection operation is completed, the conveyor belt 28 is rotated in the reverse direction so that the test piece can be reliably collected.

For this reason, if the user suddenly tries to detect a metallic foreign object with respect to the object before the test is repeated N times, the object is detected by the photoelectric tube in step S6, and then the detection voltage is determined in step S7. The test object is returned to the start point by the reverse operation of the belt conveyor regardless of the result, and therefore the test object does not flow to the next step before the test by the test piece is completed.

Therefore, in the metal detecting device according to the second embodiment, like the metal detecting device according to the first embodiment, an intermittent noise or "test piece is being conveyed" during the operation period of the test mode. A warning action such as "is not necessary.

5 to 7 are views showing a metal detecting device according to a third embodiment of the present invention. FIG. 5 is an external perspective view thereof, and FIG. 6 is a block diagram showing its functional structure. ,
FIG. 7 is a flow chart showing an operation procedure in the case of performing a test as to whether the metal detecting means normally operates (test mode).

Whereas the metal detecting devices according to the first and second embodiments have the carrying means, the metal detecting device according to the third embodiment does not have the carrying device in particular. It is related to the type.

The metal detector 60 shown in FIG. 5 is shaped like a box as you can see, and above the inside is
A metal detection circuit (metal detection means) including the search coil 100 as described with reference to FIG. 9 in the conventional example.
Is stored. In this metal detection device 60, a magnetic flux is emitted upward from the ceiling surface 60a of the ceiling surface 60a.
When the metal passes above a, the magnetic flux is changed, and the detection voltage becomes higher than the reference value like the metal detection devices according to the first and second embodiments, and the presence of the metal foreign matter is detected. be able to.

For example, by holding the loaf bread 1 as shown in the figure by hand and passing the loaf bread 1 along the region of the length L on the ceiling surface 60a of the metal detection device 60, the loaf bread 1 is
If there is a metallic foreign matter inside, it is possible to reliably detect it.

Reference numeral 62 is an operation control section for operating the metal detection device 60 by the user operating it, or for controlling the operation of each part thereof. Code 64
Is a display section formed of liquid crystal or the like, and displays a message to that effect if the metal detection means has not been tested for normal detection operation immediately after activation of the metal detection device 60.
After the test is completed, the detection result of the metallic foreign matter by the metal detecting means is displayed.

As shown in FIG. 6, in addition to the above-mentioned metal detection circuit, the metal detection device 60 includes a discrimination means 40, a control means 45, which is the same as the metal detection devices according to the first and second embodiments.
In addition to having the counter 48 and the warning means 50, the display means 64 as described above is provided, and the transport means is omitted as described above.

Below, based on the flow chart of FIG.
The operation in the test mode in the metal detection device according to the third embodiment will be described.

First, when the metal detector 60 is turned on, the test mode is preferentially entered (step S1) as in the first and second embodiments, and then the number of tests is measured in step S2. The count value of the counter 48 is set to "0". Next, hold the test piece by hand,
The metal detection device 60 is moved along the region in the length direction L (step S3).

Next, the metal detection means including the search coil in the metal detection device 60 performs the detection operation on the metal sphere in the test piece due to the change of the magnetic flux, and the detection voltage by the search coil is the detection voltage in the test piece. It is determined whether it is larger than a value obtained by subtracting 20% from a predetermined reference value corresponding to the size of the metal ball (step S4).

If YES in step S4, 1 is added to the count value "0" of the counter 48 to make it "1" (step S5). Next, the control means 45 determines whether the test has been performed N times by the signal from the counter 48 (step S6). If NO, the process returns to step S3 and the subsequent steps are repeated as described above.

When this is repeated N times and YES is determined in step S6, the control means 45 terminates the test mode program without turning off the power source and switches to the normal program, whereby the metal detecting means is started. It becomes possible to perform the operation of detecting the metallic foreign matter with respect to the subject.

In step S4, when the detected voltage is smaller than the predetermined value as described above (NO), the control means 45 which has input a signal indicating this from the discrimination means 40.
Turns on the buzzer that outputs a signal to the warning means 50 to notify the abnormality (step S7), and turns off the power source of the metal detection means (step S8). As a result, it is possible to prevent the detection of the metallic foreign matter from being detected in the object under the condition that the detection capability of the metallic detection means is not normal, and to reliably prevent the detection failure of the metallic foreign matter.

In the metal detecting apparatus according to the third embodiment, when the user suddenly performs the foreign metal detecting operation on the object before the test is performed N times, the display section 64 displays "Test The display of "Not performed yet" is continued, and the detection result of the metallic foreign matter cannot be displayed on the display unit 64.

In the metal detecting apparatus according to the first embodiment, in order to inform that during the operation period of the test mode, a display of "transporting the test piece" and a warning operation by an intermittent sound are performed. However, as a visual display method, you can use something like a police light attached to the roof of the police police car, and instead of an intermittent sound as an auditory sound,
A voice such as "currently under test" may be stored in the memory and uttered.

In the metal detecting apparatus according to the second embodiment, the buzzer for notifying the abnormality when the test fails is operated. However, a bell, a chime, or a voice synthesis memory is used in addition to the buzzer. The warning means may be used, a warning display for visual display may be used together with such a sound warning means, or only the visual warning display may be used.

Further, in the metal detecting apparatus according to the above-mentioned embodiment, the belt conveyor is used as the conveying means, but the present invention can be applied to a metal detecting apparatus having a conveying means other than the belt conveyor. it can.

[0073]

As described above, according to the present invention, a test is made as to whether or not the metal detecting means normally operates before the metal detecting means performs the operation of detecting the metallic foreign matter in the object. The control means enables the metal detection means to perform the detection operation of the metal foreign matter on the object when the test is passed, and when the test is not performed or the test fails, the control means controls the transport means. Since the transport operation is stopped, it is possible to reliably prevent the operation of detecting a metallic foreign substance from the object while the detection capability of the metal detecting means is not normal, and the metallic foreign object is mixed in due to the detection failure. It is possible to reliably prevent the sample from flowing to another product processing step.

In the metal detecting device according to the second embodiment, the conveyor belt 28 is used every time a test is performed.
Since the test piece is returned to the original starting position by reversing the test piece, it is possible to prevent the test piece from flowing to another manufacturing process and to reliably collect the test piece.

Further, in the metal detecting apparatus according to the third embodiment, even in the metal detecting apparatus having no carrying means, the object to which the foreign metal is mixed due to the detection failure is similar to the metal detecting apparatus having the carrying means. Can be reliably prevented from flowing to other product processing steps.

[Brief description of drawings]

FIG. 1 is a block diagram showing a functional configuration of a metal detection device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation procedure in a test mode in the metal detection device according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a functional configuration of a metal detection device according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing an operation procedure in a test mode in the metal detection device according to the second embodiment of the present invention.

FIG. 5 is an external perspective view of a metal detection device according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a functional configuration of a metal detection device according to a third embodiment of the present invention.

FIG. 7 is a flowchart showing an operation procedure in a test mode in the metal detection device according to the third embodiment of the present invention.

FIG. 8 is an external perspective view showing a conventional metal detection device.

9 is a block circuit diagram showing a search coil 100 in a coil built-in casing 32 of the metal detection device shown in FIG. 8 and a metal detection circuit connected thereto.

10 is an external perspective view showing a test piece formed by the chip 10 in which the standard metal balls 15 are embedded. FIG.

[Explanation of symbols]

 1 Bread 10 Chip 15 Standard Metal Ball 25 Motor 26 Driven Vehicle 28 Conveyor Belt 31 Main Body 32 Coil Built-in Casing 32a Tunnel Passage 34 Operation Control Device 40 Discriminating Means 45 Control Means 48 Counters 50, 51 Warning Means 53 Reversing Means 60 Metal Detecting Devices 60a Ceiling surface 62 Operation control unit 64 Display unit 100 Search coil 101 Excitation unit 103 Excitation coil 201, 201a, 201b Reception coil 202 Low frequency amplification unit 203 Comparison unit 204 Filter

Claims (7)

[Claims] 1. A transport means having a transport path for transporting an object to which a metal foreign matter may be mixed, and a presence or absence of a metal foreign matter which may be mixed in the object, which is provided in the middle of the transport path. A metal detecting unit having a magnetically detecting detecting unit, and a detecting operation for a test piece before the metal detecting unit performs the detecting operation for the object, and whether the metal detecting unit operates normally In addition to determining whether or not the test has been performed, determining means that determines whether the test has passed or failed, and if the test has passed, the metal detection means performs a detection operation for the subject. And a control means for stopping the carrying operation of the carrying means when the test is not performed or when the test fails, Detection device. 2. The test on the test piece is performed within a predetermined time and, if the test is passed, the control means enables the metal detection means to perform detection operation on the object, and the test is performed for the predetermined time. A metal detecting device characterized in that the carrying operation of the carrying means is stopped when not carried out. 3. The control means enables the metal detection means to perform a detection operation on the object when the test on the test piece has passed a predetermined number of times consecutively, and when the test is not performed or even once. A metal detecting device characterized in that when the test fails, the carrying operation of the carrying means is stopped. 4. After the test is performed by passing the test piece through the detection portion of the metal detection means, the conveyance direction of the conveyance means is reversed to bring the test piece to the original start position. 4. The metal detecting device according to claim 1, wherein the carrying operation of the carrying means is stopped at. 5. A metal detection means for magnetically detecting the presence or absence of a metallic foreign matter that may be mixed in a subject, and a test piece before the metal detection means performs the detection operation for the subject. The detection operation determines whether or not a test has been performed as to whether the metal detection means operates normally, and a determination means for determining whether the test has passed or failed, and a warning in a predetermined case. And a warning unit that causes the metal detection unit to perform a detection operation on the object when the test is passed, and a control that issues a warning to the warning unit when the test is not performed. A metal detecting device comprising: 6. A warning means is provided for visually or audibly warning during the operation period of the test mode during the operation period of the test mode in which the detection operation is to be performed with the highest priority after the activation. The metal detection device according to claim 1, wherein the metal detection device is a metal detection device. 7. A second warning means for issuing a warning when the test fails is provided.
The metal detection device according to claim 5.