KR100298597B1 - Method and apparatus for detecting metal strip on conveyer belt for transferring raw materials - Google Patents

Abstract

PURPOSE: A method and apparatus for detecting metal strip on conveyer belt for transferring raw materials is provided to prevent conveyor belt from being damaged by the metal strips, while allowing the metal strips to be easily removed. CONSTITUTION: An apparatus comprises a transmitting coil(11) and a receiving coil arranged on above and underneath a conveyer belt(B), respectively. The receiving coil includes a first receiving coil(12) and a second receiving coil which are continuously arranged in the lengthwise direction of the conveyor belt. A method comprises a first step of defining a transport speed of conveyer belt; a second step of detecting a signal on the metal strip by examining change in magnetic flux caused due to the action of transmitting and receiving coils, and obtaining information regarding the width and thickness of the metal strip by using the size of the detected signal; a third step of obtaining information on the length of the metal strip by using the detected size; and a fourth step of removing the metal strip in accordance with the result.

Description

Metal piece detection method on conveyor belt for raw material conveying and apparatus thereof

The present invention relates to a method for detecting a metal piece on a conveyor belt for raw material transfer and a device thereof, and is particularly included in a raw material (iron ore) which is a direct factor of shortening the belt's lifespan and operation failure while the belt is damaged or broken. Various metal pieces are detected by non-contact method using Eddy Current, which informs the operator of the presence or absence of metal pieces, the position of the conveyor belt direction of the metal pieces and the width of the conveyor belt width direction, and also detects the joints of the steel belt. By preventing the desensitization of the detection sensitivity due to the passage of the joint portion to effectively remove the metal piece.

In the conventional metal piece detection method, the signal of various metal pieces 14 conveyed to the conveyor belt B is detected sensitivity along the width direction of the conveyor belt B, that is, the center portion of the conveyor belt B, and the conveyor belt B. Since the sensitivity characteristic of the detector with respect to the edge portion of is significantly differentiated, when various metal pieces 14 pass through the edge portion of the conveyor belt B, the detection sensitivity is very low, which is a major cause of malfunction.

In addition, since only the positional information of the various metal pieces 14 with respect to the longitudinal direction of the conveyor belt B is provided, much time is required for metal removal.

Most of the conventional methods and apparatus for detecting metal pieces using eddy currents include an integrated type in which the transmitting coil 11 and the first and second receiving coils 12 and 16 are integrated, the transmitting coil 11, Although there is a separate type in which the first and second receiving coils 12 and 16 are dualized up and down, the magnetic coil sensor sensitivity characteristics are differentiated according to the width direction of the conveyor belt B. It is the cause.

In the conventional metal piece detectors, the metal piece detection sensitivity level, which is a standard for determining the presence or absence of various metal pieces 14, is set higher than the output signal of the joint portion of the steel belt, resulting in a decrease in detection sensitivity.

The present invention has been invented to solve the above problems in view of the conventional metal piece detector, and eliminates the detection sensitivity level differentiation of the metal piece detector, and is due to the output signal level generated when the metal piece detector passes through the steel belt joint. Sensor sensitivity can be prevented from desensitization, making it easy to detect metal pieces lower than the signal level for the joint, and by using accurate positioning and size (thickness, width, and length) information of metal pieces for automatic removal of metal pieces, The purpose is to prevent the breakage and damage of the conveyor belt, as well as to facilitate the removal of metal pieces.

The method of the present invention having such an object comprises the steps of first obtaining a moving speed of a conveyor belt carrying raw materials by the following equation;

Distance traveled by the conveyor belt during the width section of the first metal piece detection signal

κ = ------------------------------------------------ ------------------

The time the conveyor belt moved during the width section of the first metal piece detection signal.

Obtaining information on the width and thickness of the metal piece by the magnitude of the metal piece detection signal, obtaining information on the length of the metal piece by the magnitude of the metal piece detection signal width, analyzing and sheeting the information of the steps; It is characterized by consisting of a process of removing the metal piece to inform the operator of the analysis and the determined result.

The present invention also provides a metal piece detecting device for detecting a metal piece as a waveform diagram measured from the receiving coil by installing a transmitting coil and a receiving coil on the upper and lower portions of the conveyor belt for carrying ore, respectively. Is composed of a first receiving coil and a second receiving coil continuous in the longitudinal direction of the conveyor belt, the plate-shaped first receiving coil and the second receiving coil from one side end to the other end in the transverse direction of the bottom side of the conveyor belt. It was installed so that it could be leveled out.

On the other hand, a plurality of first receiving coils and second receiving coils are connected to each other so as to be installed so as to extend from one side end of the conveyor belt to the other end of the conveyor belt. It is done.

1 (a), (b) and (c) are working state diagrams for explaining the metal piece detection state of the present invention,

2 is a block diagram showing a metal piece detection system of the present invention;

3 (a) to (g) are waveform diagrams showing respective signal shapes measured from the receiving coil of the present invention,

(A)-(e) is a perspective view which shows the coil structure of this invention and its mounting state,

5 (a), (b), (c), and (d) are working state diagrams for explaining a metal piece detection state according to another embodiment of the present invention;

6 is a block diagram showing a metal piece detection system according to another embodiment of the present invention;

7 (a) to 7 (g) are waveform diagrams showing respective signal types measured from the receiving coils according to another embodiment of the present invention.

8 (a) (b) (c) are perspective views of a coil structure and a mounted state of another embodiment of the present invention;

9 is a block diagram for explaining a metal piece detecting method of the present invention;

10 is a waveform diagram for explaining a metal piece detection signal analysis of the metal piece detection method of the present invention;

11 is a graph showing a metal piece discrimination method of the present invention;

12 is a flowchart of a metal piece discrimination method executed in the signal processing section of the present invention.

<Description of the symbols for the main parts of the drawings>

11: Outgoing coil 12, 16: First and second receiving coil

14 metal part 15 iron ore

17: seam 18: steel

30: coil body 31: top plate

32: lower plate 33: middle plate

34: coil 35: casing

38: support

1 is an operation state diagram for explaining the detection state of the metal piece of the present invention, the magnetic flux generated in the transmission coil 11 will have the same effect on the two receiving coils 12, 16 located at the same distance, In addition, the same induced voltage is generated at the two receiving coils 12 and 16.

Therefore, if there is a metal piece 14 between the transmitting coil 11 and the two receiving coils 12, 16, the amount of signal change in the two receiving coils 12, 16 that change due to this Since the signal difference between the two receiving coils 12 and 16 is obtained by the signal comparison detecting unit, the signals are always kept constant regardless of the presence or absence of iron ore.

By using this principle, the metal piece detection signal generated by the pure metal piece 14 is transmitted to the metal piece 14 passing through the two receiving coils 12 and 16 in the conveyor belt B regardless of the type of the iron ore. You get it.

The detected metal piece detection signal is amplified by the signal amplifier and then converted into an average value by the rectifying circuit unit and the mean-absolute value (MVA) measuring unit and input to the signal processing unit through the signal measuring unit.

The metal piece detection signal is acquired by the signal processing unit when the synchronization signal output from the synchronization signal generation unit becomes high together with the output value of the counter for measuring the rotation amount of the roll.

Determination of the width and thickness of the metal piece 14 is a period (24), (25), (26) larger than the MVA (Mean-absolute Value) output signal converted by the metal piece 14 as shown in FIG. While obtaining the largest value of the MVA output signal, the thickness and width of the metal piece 14 are determined by the change in the magnitude of the signal.

And the length determination of the metal piece 14 is calculated | required by the time during the sections 24, 25, and 26 which became larger than the MVA output signal threshold changed by the metal piece 14, and the moving speed of a belt. .

In FIG. 10, when the moving speed of the belt during the section “24” is χ to determine the length of the metal piece 14 due to the metal piece detection signal 21,

(24) Distance the belt moved during the section

χ = -------------------------------------

24 hours

Since the equation is established, the distance traveled by the belt during the "(24)" section is obtained by counting the output of a constant value per one revolution of the roll, and the time during the (24) section is 30HZ because the synchronization signal is 30HZ. The number of pulses of the synchronous signal during the operation is x (1/30) seconds.

One

Length of metal piece = number of sync signal pulses in χ × ----- sec × ”(24)” section

30

Obtained by

If the speed of the belt is constant, it can be seen that an important factor in determining the length of the metal piece 14 is the number of synchronization signal pulses during the metal piece detection signal section.

As can be seen from FIG. 11, the metal piece can be determined based on the length of the metal piece and the width and thickness information of the metal piece.

Then, after the belt is stopped to the position where the metal piece 14 is located, the operator is informed of the distance moved by the conveyor belt B during the sections (27), (28) and (29) of FIG.

The device of the present invention is a separate type in which the transmitting coil 11 and the receiving coils 12 and 16 are divided up and down, and are easily maintained in case of breakage, and the receiving coils 12 and 16 have two coils. Since it is comprised, the signal by an iron ore and the signal by the metal piece 14 are distinguished, and the separate sensitivity adjustment according to the kind of iron ore is unnecessary.

In addition, since external vibration and noise are simultaneously sensed by the two receiving coils 12 and 16, the signal comparison detection unit cancels out and removes the cause of the malfunction due to the influence.

Since the commercial power is used as the excitation signal of the transmission coil 11, the transmission signal is not required separately, thereby simplifying the structure of the apparatus. The conveyor belt (B) generated by missing the metal piece 14 is stored in the signal processing part after the information of the metal piece 14 continuously passing through the iron piece detector is notified to the operator through the detection display part. ) It is a device to prevent breakage and damage.

1 is an operation diagram for explaining a metal piece detection state, showing a configuration in which the transmission coil 11 is located parallel to the upper side of the conveyor belt (B) and the receiving coil 12 is located parallel to the lower side, which is the transmission The magnetic flux generated in the coil 11 connects the receiving coil 12 and maintains the voltage in the receiving coil 12.

If the metal piece 14 exists between the transmitting coil 11 and the receiving coil 12, the magnetic flux generated in the transmitting coil 11 generates an eddy current on the surface of the metallic piece 14.

Since the magnetic flux is generated in the opposite direction to the magnetic flux generated in the transmission coil 11 by the eddy current generated on the surface of the metal piece 14, the magnetic flux induced in the receiving coil 12 is reduced, thereby receiving the receiving coil 12 Reduce the induced voltage at

As described above, the metal piece 14 on the conveyor belt B is detected by the amount of change in the signal generated by the receiving coil 12.

However, if the metal piece 14 is buried in the iron ore 15 containing a large amount of iron (Fe) component, the detection of the metal piece 14 relatively small compared to the iron ore 15 due to the change of the magnetic field by the iron ore 15 It becomes impossible.

In order to eliminate this cause, the first receiving coil 12 and the second receiving coil 16 are continuously installed in the conveyor belt B moving direction on the lower surface of the conveyor belt B.

The magnetic flux generated from the transmitting coil 11 exerts the same influence on the two receiving coils 12 and 16 located at the same distance and generates the same induced voltage on the two receiving coils 12 and 16. Let's do it.

If the iron ore 15 is present between the transmission coil 11 and the two reception coils 12 and 16, the amount of change in the signal at the two reception coils 12 and 16 which changes due to this. Since is the same, the difference between the signals in the two receiving coils 12 and 16 will always maintain a constant signal regardless of whether or not the iron ore 15 is present.

Using this principle, the signal generated by the pure metal piece 14, regardless of the type of the iron ore 15, for the metal piece 14 passing through the two receiving coils 12 and 16 in the conveyor belt B. Will be detected.

FIG. 2 is a block diagram illustrating a metal piece detecting method of the present invention, in which signals generated by being induced in the receiving coils 12 and 16 by the magnetic flux generated in the transmitting coil 11 (FIG. 3 (a)). The difference between the two signals is input to the signal comparison detection unit. At this time, if the metal piece 14 passes through the upper portion of the first receiving coil 12, the second (2b) is not affected by the signal (Fig. 2 (b)) and the metal piece 14 of the first receiving coil (12). The signal (FIG. 3 (c)) of the receiving coil 16 is input to the signal comparison detection unit so that the difference signal when it is not present when the metal piece 14 is present, that is, the signal generated by the pure metal piece 14 (Fig. 3 (d)) is detected.

This signal is input to the signal measuring unit and synchronized with the signal from the synchronizing signal generator (Fig. 3 (e)) to obtain a peak value of the signal, which is transferred to the signal processing unit and stored in the memory in the signal processing unit. .

Then, the information on the metal piece 14 is displayed on the detection display unit so as to be recognized by the operator, and a control signal for stopping the drive belt driving motor of the conveyor belt B is sent.

In addition, since the information about the metal pieces 14 continuously passing through the detector is stored in the memory of the signal processing unit, the effect of preventing damage and breakage of the conveyor belt B by the metal pieces 14 passing through the detector is prevented. Have

4 shows the configuration of the coils. In (a), the upper and lower parts are covered by the upper plate 31 and the lower plate 32, and the coil body 30 in which the middle plate 33 is wound by the coil 34 is shown. The coil body 30 is a main component constituting the transmitting coil 11 and the receiving coils 12, 16 shown in (b) and (c).

That is, the receiving coil of FIG. 4 (b) processes the first receiving coil 12 and the second receiving coil 16 therein, and the receiving coils 12 and 16 are housed in the casing 35. 4 (c) shows that the transmission coil 11 is accommodated inside the casing 35.

The receiving coils 12, 16 and the transmitting coil 11 as described above are positioned on the upper and lower sides of the conveyor belt B as shown in FIGS. 4 (d) and (e), respectively, on the support frame 38. I support it.

In this way, the experiment was performed, and the distance between the transmitting coil 11 and the receiving coils 12, 16 was supplied to the transmitting coil 11 as the excitation signal to supply commercial power (100 [V], 60 [HZ]). At the time, the minimum interval for detecting the minimum specimen to be detected by the metal piece detector was set at the detection part of the sensor.

The positions of the first receiving coil 12 and the second receiving coil 16 were set where each output kept the same value.

On the other hand, the metal piece detection method of this invention is demonstrated as follows.

The transmission coil 11 is positioned on the upper side of the conveyor belt B, and the receiving coil 12 is positioned in the form of a cross section of the belt on the lower side, and the magnetic flux generated by the transmission coil 11 is a multiple coil. The receiving coil 12 configured to be eliminated to induce a voltage to the receiving coil 12.

If the metal piece 14 exists between the transmitting coil 11 and the receiving coil 12, the magnetic flux generated in the transmitting coil 11 generates an eddy current on the surface of the metallic piece 14. Due to the eddy current generated on the surface of the metal piece 14, the magnetic flux is generated in a direction opposite to the magnetic flux generated in the transmitting coil 11, thereby reducing the magnetic flux induced in the multiple coils of the receiving coil 12 in which the metal piece 14 is located. The cause is to reduce the voltage induced in the multiple coils of the receiver directly below the metal piece 14 is located.

In the same basic principle as described above, the metal pieces 14 on the conveyor belt B are detected by the amount of change in the signal generated in each of the multiple coils of the receiving coil 12.

However, if the metal piece 14 is buried in the iron ore 15 containing a large amount of iron (Fe), due to the change in the magnetic field in the iron ore 15 it is impossible to detect the relatively small metal piece 14 compared to the iron ore (15). Done.

In order to eliminate this cause, the first receiving coil 12 and the second receiving coil 16 made of multiple coils are continuously installed in the conveyor belt B moving direction on the lower surface of the conveyor belt B.

The magnetic flux generated from the transmitting coil 11 exerts the same effect on the two receiving coils 12 and 16 located at the same distance, and the iron ore 15 between the two receiving coils 12 and 16. If is present, the amount of change in the signal at each of the multiple coils of the two receiving coils 12, 16, which is changed due to this, is the same, so that the signal at these two receiving coils 12, 16 Finding a car always maintains a constant signal whether or not iron ore 15 is present or not.

Using this principle, the signal generated by the pure metal piece 5 regardless of the type of the iron ore 15 for the metal piece 14 passing through the two receiving coils 12 and 16 in the conveyor belt B is used. Will be detected.

If the joint 17 of the steel belt passes through the metal piece detector, the detection sensitivity level is set higher than that of the steel belt joint through the conventional metal piece detector to detect the metal piece lower than the signal level. You will not.

In order to prevent the above-described desensitization of the metal piece detection sensitivity level, the first receiving coil 12 and the second receiving coil 16 are multi-coiled in an arc shape in the belt width direction and installed continuously.

When the magnetic flux generated from the transmitting coil 11 passes through the joint portion of the steel belt, the plurality of first receiving coils 12, which are the first receiving coil bodies, pass.

At this time, the plurality of first receiving coils 12 detects a passing signal corresponding to the steel belt joint.

In the present invention as described above, since the receiving coil portion of the conveyor belt is single or multiple coils in the horizontal and arc shapes in the belt width direction, the sensitivity of the belt edge portion is reduced and the detection sensitivity level is reduced by detecting the joint portion of the steel belt. It is possible to prevent the damage of the conveyor belt due to the metal piece by preventing the deterioration phenomenon, as well as to facilitate the removal of the metal piece by recognizing the position of the belt width direction and the longitudinal direction of the metal piece.

Claims (3)

Obtaining a moving speed of a conveyor belt carrying raw materials by the following equation, Distance traveled by the conveyor belt during the width section of the first metal piece detection signal κ = ------------------------------------------------ ------------------ The time the conveyor belt moved during the width section of the first metal piece detection signal. Detecting the metal piece by the change of the magnetic flux generated by the action of the transmitting coil and the receiving coil installed above and below the conveyor belt and acquiring information on the width and thickness of the metal piece by the magnitude of the detected signal; Acquiring the length information of the metal piece by the size of the width, and analyzing and determining the information of the processes, and notifying the operator of the result, and removing the metal piece. . In the metal piece detecting device for detecting the metal piece as a waveform diagram of the magnetic flux measured from the receiving coil by installing the transmitting coil 11 and the receiving coil respectively on the upper and lower portions of the conveyor belt (B) for carrying ore, etc. The receiving coil comprises a first receiving coil 12 and a second receiving coil 16 continuous in the longitudinal direction of the conveyor belt B, and the first receiving coil 12 and the second receiving coil 16. The metal piece detection device on the conveyor belt for raw material conveyance, characterized in that formed in a plate shape so as to maintain a horizontal in the transverse direction of the bottom side of the conveyor belt (B). The first receiving coil 12 and the second receiving coil 16 are installed so as to extend from one end to the other end in the transverse direction of the bottom of the conveyor belt B. Metal piece detection device on a conveyor belt for raw material transfer, characterized in that the arc shape to match the cross-sectional shape.