JPH1029717A - Method to detect crack in longitudinal direction of conveyor belt and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to detect cracks in the longitudinal direction of a conveyor belt, which can surely detect cracks in the longitudinal direction of the conveyor belt even if the conveyor belt is shifted. SOLUTION: First and second millimeter wave radar units 21a and 21b are arranged in series in the cross direction of a conveyor belt 4 to measure the turnaround time of electromagnetic waves at an interval of given time by radiating electromagnetic waves of millimeter wave to the belt face of the conveyor belt 4 and receiving reflected waves. In addition, electromagnetic waves are scanned by a millimeter wave radar in the cross direction of the conveyor belt 4, and the turnaround times of the electromagnetic waves, which is measured by the millimeter wave radar, are memorized in first and second memory sections 22a and 22b given times in succession as time data, and based on a plurality of this memorized and successive time data, the cracks in the longitudinal direction of the conveyor belt 4 is detected by a central processing section 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detecting a vertical crack in a conveyor belt that detects a vertical crack generated in a conveyor belt in use.

[0002]

2. Description of the Related Art Conventionally, a large-sized conveyor belt has been used to transport a conveyed object such as ore. When ores and the like are transported by such a conveyor belt, there are many cases where the ore projections or the like cause scratches or vertical cracks due to ore protrusions when the ore is dropped into the conveyor belt or during transportation.

[0003] When the conveyor belt is longitudinally cracked in this way, not only does it hinder the conveyance operation, but also suffers a great deal of damage.

For this reason, the conveyor belt is provided with a vertical crack detecting device for detecting a vertical crack. Various types, such as an exterior type and an interior type, are known as such a vertical crack detection of the conveyor belt.

FIG. 2 is a configuration diagram showing an example of the above-described interior vertical crack detecting device. In the figure, reference numeral 1 denotes a conveyor device, which is composed of a driving pulley 2, a driven pulley 3, a conveyor belt 4 extended over the driving pulley 2 and the driven pulley 3, and an electric motor 5 for rotating the driving pulley 2.

As shown in FIG. 3, a plurality of objects to be detected are embedded in the conveyor belt 4 at predetermined regular intervals in the longitudinal direction. The detected object is, for example, a coil 6
A part of the conductive wire forming the coil 6a extends in the width direction of the conveyor belt 4 and is buried in the conveyor belt 4. The resonance frequency of the resonance circuit 6 is about 650 KH
z.

Further, the drive pulley 2 is provided with an encoder 7, and the encoder 7 outputs a pulse signal at every predetermined number of rotations. The output timing of the pulse signal is set in synchronization with the movement of the resonance circuit 6 embedded in the conveyor belt 4.

On the other hand, below the conveyor belt 4, three detectors 8a to 8c are fixedly disposed, and these detectors 8a to 8c are connected to the conveyor belt 4 as shown in FIG.
Are displaced little by little in the width direction.

As shown in FIG. 5, the detecting units 8a to 8c respectively include an antenna coil 81 and an oscillating circuit 8.
2. A determination circuit 83 is provided, and an AC signal having a frequency of about 650 KHz is supplied from the oscillation circuit 82 to the antenna coil 81. Further, the determination circuit 83 is configured to output the AC signal A supplied from the oscillation circuit 82 to the antenna coil 81.
And a timing pulse signal TP output from the encoder 7, the presence or absence of an abnormality in the resonance circuit 6 is determined based on these signals, and an abnormality signal D is output when an abnormality occurs.

According to the conveyor belt longitudinal crack detecting device having the above-described configuration, when the conveyor belt 4 has no longitudinal crack, each resonance circuit 6 operates normally and the detecting section 8a
When the resonance circuit 6 is located above the antenna circuit 81 through 8c, the antenna coil 81 and the resonance circuit 6 are electromagnetically coupled. As a result, the energy radiated from the antenna coil 81 is absorbed by the resonance circuit 6, and the level of the AC signal supplied to the antenna coil 81 is reduced, so that the normality of the resonance circuit 6 is confirmed.

When the conveyor belt 4 in use is longitudinally cracked due to a projection of a falling object or the like, the conductive wire constituting the coil 6a of the resonance circuit 6 embedded in the conveyor belt 4 is cut off. Since the resonance circuit 6 does not operate,
The energy radiated from the antenna coil 81 is not absorbed by the resonance circuit 6. For this reason, since the level of the AC signal supplied to the antenna coil 81 does not decrease, abnormality of the resonance circuit 6 is detected. Thereby, the vertical crack of the conveyor belt is detected. When the vertical crack of the conveyor belt 4 is detected in this way, the determination circuit 83
Is output, and the electric motor 5 is stopped.

Further, although the conveyor belt 4 may be shifted in the width direction during the conveyance, the state of the resonance circuit 6 can be reliably detected because the plurality of detectors 8a to 8c are arranged as described above. be able to.

[0013]

However, according to the above-described conventional conveyor belt longitudinal crack detecting device, when the conveyor belt 4 is largely displaced in the width direction, the resonance circuit 6 is not provided.
In order to prevent the coil 6a from being deviated from above the detecting section and thereby causing a malfunction, it is necessary to dispose a plurality of detecting sections like the detecting sections 8a to 8c in the width direction of the conveyor belt. In addition, if a large number of the detection units 8 are provided, a malfunction due to a shift of the conveyor belt 4 can be avoided, but the cost becomes very high.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a conveyor belt longitudinal crack detection method and apparatus capable of reliably detecting a conveyor belt longitudinal crack even if the conveyor belt shifts. .

[0015]

According to the present invention, in order to achieve the above object, according to the present invention, a millimeter-wave radar radiates a millimeter-wave electromagnetic wave to a belt surface of a conveyor belt and receives a reflected wave. Of the electromagnetic wave by the millimeter-wave radar is scanned in the width direction of the conveyor belt, and the round-trip time of the electromagnetic wave measured by the millimeter-wave radar is determined as time data. A method for detecting a vertical crack in the conveyor belt, which stores several consecutive time data and detects a vertical crack in the conveyor belt based on the stored plurality of continuous time data, is proposed.

According to the method for detecting a vertical crack in the conveyor belt, the millimeter-wave radar radiates the millimeter-wave electromagnetic waves to the belt surface of the conveyor belt. Thereby, the millimeter-wave electromagnetic wave is reflected by the belt surface, and the reflected wave is received by the millimeter-wave radar. Further, the radiation direction of the electromagnetic wave by the millimeter wave radar is scanned in the width direction of the conveyor belt, and the reciprocating time of the electromagnetic wave is measured at predetermined time intervals. As a result, the reciprocating time of the electromagnetic wave measured by the millimeter wave radar is continuously stored as time data by a predetermined number, and the longitudinal crack on the belt surface is detected based on the time data. For example, if a vertical crack is formed on the belt surface of the conveyor belt, the round-trip time of the electromagnetic wave at the vertical crack position is locally changed as compared to before and after the vertical crack, whereby a vertical crack can be detected.

According to a second aspect of the present invention, a millimeter-wave electromagnetic wave is radiated to the belt surface and a reflected wave is received, and the round-trip time of the electromagnetic wave is measured at predetermined time intervals. At least one millimeter-wave radar that outputs the electromagnetic waves emitted by the millimeter-wave radar, a scan driving unit that scans the radiation direction of the electromagnetic waves by the millimeter-wave radar in the width direction of the conveyor belt; A conveyor belt comprising: storage means for continuously storing a predetermined number of data as data; and longitudinal crack detection means for detecting a longitudinal crack in the conveyor belt based on a plurality of continuous time data stored in the storage means. We propose a vertical crack detection device.

According to the conveyor belt longitudinal crack detecting device, the millimeter wave radar radiates the millimeter wave electromagnetic waves to the belt surface of the conveyor belt. Thus, the millimeter-wave electromagnetic wave is reflected by the belt surface, the reflected wave is received by the millimeter-wave radar, and the round-trip time of the electromagnetic wave is measured at predetermined time intervals. Further, the radiation direction of the electromagnetic wave by the millimeter wave radar is scanned in the width direction of the conveyor belt by scanning driving means, and the round trip time of the electromagnetic wave measured by the millimeter wave radar is stored as time data by the storage means, A predetermined number is continuously stored, and a vertical crack on the belt surface is detected by the vertical crack detecting means based on the time data. For example, if a vertical crack is formed on the belt surface of the conveyor belt, the round-trip time of the electromagnetic wave at the vertical crack position is locally changed as compared to before and after the vertical crack, whereby a vertical crack can be detected.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a conveyor belt longitudinal crack detecting device according to an embodiment of the present invention.
FIG. 3 is a block diagram showing an electric circuit. In the figure, the same components as those of the above-described conventional example are denoted by the same reference numerals, and description thereof will be omitted. The difference between the present embodiment and the conventional example is that a detection unit 20 is provided in place of the detection target and the detection units 8a to 8c mainly including the resonance circuit 6 in the conventional example.

That is, below the conveyor belt 4 immediately after the hopper 13, the detection unit 20 is fixedly disposed. As shown in FIG. 6, the detection unit 20 includes first and second millimeter wave radar units 21a and 21b, first and second storage units 22a and 22b, a central processing unit 23,
It is composed of a keyboard 24, a display unit 25, and a notification unit 26.

First and second millimeter wave radar units 21
Each of a and 21b includes a waveguide unit 211, a drive unit 212, an oscillator 213, a receiver 214, and a timer unit 215, as shown in FIG. They are arranged in series in the width direction.

The waveguide unit 211 receives a high-frequency current from the oscillator 213, radiates the high-frequency current as a millimeter-wave electromagnetic wave having a predetermined frequency in one specific direction, and receives the millimeter-wave electromagnetic wave incident from the substantially same direction as the radiation direction. Is converted to a high-frequency current and output to the receiver 214.

Further, the waveguide unit 211 includes a driving unit 212
Is rotated within a predetermined angle. That is, the electromagnetic wave radiated from the waveguide unit 211 by the rotation of the driving unit 212 is scanned in the width direction of the conveyor belt 4. Further, electromagnetic waves are applied to the entire width of the conveyor belt 4 by the two radar units 21a and 21b.

The oscillator 213 outputs a pulsed high-frequency current of a predetermined frequency to the waveguide unit 211 when the radiation timing signal S from the timer 215 is input.

The receiver 214 detects a pulse signal having substantially the same frequency as that output from the oscillator 213 from the high-frequency current input from the waveguide unit 211, converts the pulse signal into a digital signal R, and outputs the digital signal R to the timer 215. I do.

The timer 215 outputs the radiation timing signal S every 0.01 second, for example, and outputs the radiation timing signal S
Is output, the time until the digital signal R is input from the receiver 214 is measured, and the measured time is converted into a digital value and output.

The first and second storage units 22a, 22a
b, the measurement time data output from the corresponding first and second millimeter wave radar units 21a and 21b are input, and the measurement time data for one scan is stored.

The central processing unit 23 comprises a well-known CPU 231 and a memory 232, and the CPU 231 performs first and second scans for each scan of the millimeter wave radar units 21a and 21b based on a program stored in the memory 232. The measurement time data for one scan is read from the second storage units 22a and 22b, and a vertical crack detection process of the conveyor belt 4 is performed using the read data. This is displayed on the display unit 25. The occurrence is notified through the notification unit 26.

Further, the notification unit 26 outputs an alarm signal K to a drive control unit (not shown) of the motor 5 in response to the notification of the occurrence of the vertical crack, thereby stopping the driving of the motor 5.

Next, the operation of the longitudinal crack detecting device having the above-described configuration will be described with reference to the flowchart shown in FIG.
First, the CPU 231 of the central processing unit 23
The measurement time data for one scan stored in 2a is read (SA1), the difference between two consecutive time data is calculated (SA2), and the difference value is equal to or greater than a preset detection reference value. It is determined whether or not there is (SA3).

For example, as shown in FIG.
The normal measurement time data when the irradiation position of the electromagnetic wave radiated from the waveguide unit 211 is scanned once from point A to point B on the conveyor belt surface, that is, when the conveyor belt has no longitudinal crack The measured time data changes in a predetermined curve as shown in FIG.

On the other hand, as shown in FIG. 12, when a vertical crack occurs at point C of the conveyor belt 4, for example, the measurement time data is obtained at the vertical tear position (point C) as shown in FIG. It changes greatly.

Therefore, by monitoring the magnitude of the change in the measured time data, it is possible to detect a longitudinal crack generated in the conveyor belt 4.

As a result of the determination in SA4, if the calculated difference value is equal to or larger than the detection reference value, the process proceeds to SA7 described later. If the calculated difference value is smaller than the detection reference value, The measurement time data for one scan stored in the second storage unit 22b is read (SA4), and two consecutive measurement time data are read.
The difference between the two time data is calculated (SA5), and it is determined whether or not the value of the difference is equal to or greater than the above-described detection reference value (S5).
A6).

As a result of this determination, if the calculated difference value is smaller than the detection reference value, the process proceeds to SA1 described above. If the calculated difference value is equal to or larger than the detection reference value, Is determined to have a vertical crack, a message indicating that a vertical crack has occurred is displayed on the display unit 25, and a notification instruction is output to the notification unit 26 to notify the generation of the vertical crack by the notification unit 26 ( SA7).

At this time, the notification section 26 outputs an alarm signal K to a drive control section (not shown) of the electric motor 5, thereby stopping the driving of the electric motor 5 and progressing the vertical tearing of the conveyor belt 4. In addition, prevent accidents caused by longitudinal cracks.

Note that the configuration in the present embodiment is an example, and the present invention is not limited to this.

[0038]

As described above, according to the conveyor belt longitudinal crack detection method of the present invention, when a longitudinal crack occurs in the conveyor belt, the measurement time by the millimeter wave radar locally changes. The occurrence of a vertical crack in the conveyor belt can be easily detected. Further, even if the conveyor belt is largely displaced in the width direction, it is possible to perform stable detection without causing a malfunction in the detection of longitudinal cracks.

According to the conveyor belt longitudinal crack detecting device of the present invention, when a longitudinal crack occurs in the conveyor belt, the measurement time by the millimeter wave radar locally changes.
The occurrence of a vertical crack in the conveyor belt can be easily detected. Furthermore, even if the conveyor belt shifts greatly in the width direction,
Stable detection can be performed without causing a malfunction in vertical crack detection.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a conveyor belt longitudinal crack detection device according to an embodiment.

FIG. 2 is a configuration diagram showing a conventional example.

FIG. 3 is a diagram showing an object to be detected embedded in a conveyor belt in a conventional example.

FIG. 4 is a diagram showing an arrangement of detection units in a conventional example.

FIG. 5 is a configuration diagram showing a detection unit in a conventional example.

FIG. 6 is a block diagram showing an electric circuit of the conveyor belt longitudinal crack detecting apparatus according to the embodiment of the present invention;

FIG. 7 is a configuration diagram showing a millimeter wave radar unit according to an embodiment of the present invention.

FIG. 8 is a diagram showing an arrangement of a millimeter wave radar unit according to an embodiment of the present invention.

FIG. 9 is a flowchart illustrating a longitudinal crack detection process according to an embodiment of the present invention.

FIG. 10 is a diagram illustrating a scanning operation of the millimeter wave radar according to the embodiment of the present invention.

FIG. 11 is a diagram showing a transition of a measurement time value by the millimeter wave radar according to the embodiment of the present invention.

FIG. 12 is a diagram illustrating a scanning operation of the millimeter wave radar according to the embodiment of the present invention.

FIG. 13 is a diagram showing a transition of a measurement time value by the millimeter wave radar according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Conveyer apparatus, 2 ... Driving pulley, 3 ... Driving pulley,
4 ... Conveyor belt, 5 ... Electric motor, 20 ... Detection unit, 21a ... First millimeter wave radar unit, 21b ... Second millimeter wave radar unit, 211 ... Waveguide unit, 21
2 ... drive unit, 213 ... oscillator, 214 ... receiver, 215 ... clock unit, 22a ... first storage unit, 22b ... second storage unit, 2
3 central processing unit, 24 keyboard, 25 display unit, 2
6… Notification section.

Claims (2)

[Claims] 1. A millimeter-wave radar radiates a millimeter-wave electromagnetic wave to a belt surface of a conveyor belt, receives a reflected wave, measures a reciprocating time of the electromagnetic wave at predetermined time intervals, and emits the electromagnetic wave by the millimeter-wave radar. The direction is scanned in the width direction of the conveyor belt, and the round-trip time of the electromagnetic wave measured by the millimeter wave radar is stored as time data continuously for a predetermined number of times, based on the stored plurality of continuous time data, A method for detecting a vertical crack in a conveyor belt, comprising detecting a vertical crack in the conveyor belt. 2. At least a device arranged to face a belt surface of a conveyor belt, radiate a millimeter wave electromagnetic wave to the belt surface, receive a reflected wave, measure and output a reciprocating time of the electromagnetic wave at predetermined time intervals, and output the same. One millimeter-wave radar, scanning drive means for scanning the radiation direction of the electromagnetic wave by the millimeter-wave radar in the width direction of the conveyor belt, and a predetermined number of round-trip times of the electromagnetic wave measured by the millimeter-wave radar as time data. A conveyor belt comprising: storage means for continuously storing; and longitudinal crack detection means for detecting a longitudinal crack in the conveyor belt based on a plurality of continuous time data stored in the storage means. Longitudinal crack detection device.