JP2016197070A - Belt monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt monitoring device that can monitor a belt without being interrupted by powder and granular materials falling through cracks or broken parts of the belt.SOLUTION: A belt monitoring device 10 includes: a belt 29 for carrying powder and granular materials on the belt; an optical measurement unit 30 for applying a laser beam from a side where the powder and granular materials are put on to the belt 29, receiving reflecting lights of the laser beam, and measuring a time difference between a light projecting timing and a light receiving timing; and a determination unit for determining the presence or absence of cracks or broken parts of the belt 29 based on the measurement results of the optical measurement unit 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a belt monitoring device for monitoring damage to a belt of a belt conveyor during operation of the belt conveyor.

  Conventionally, a belt conveyor is used for tunnel construction. If the belt conveyor is operated intermittently or continuously for a long time, the belt may be cracked. In particular, when the earth and sand is placed on the belt by dropping the earth and sand on the belt, sharp foreign matters in the earth and sand penetrate the belt, and the belt is torn in the traveling direction, thereby causing a vertical tear in the belt. Further, cracks grow due to the tension of the belt, and the belt may be broken. In view of this, the technique described in Patent Document 1 discloses a technique for measuring the shape of the belt of the belt conveyor in operation with a laser sensor. This laser sensor is disposed below the belt, and measures the shape of the belt according to the trigonometric principle by projecting a laser beam toward the belt.

JP 2006-52039 A

  By the way, in the technique of patent document 1, since the laser sensor is arrange | positioned under the belt and the crack which arose in the belt has opened, the earth and sand on a belt will fall to a laser sensor through a crack. As a result, the laser sensor may be damaged. Moreover, the fallen earth and sand will shield a laser beam, and it will become impossible to measure the shape of a belt with a laser sensor. Even when the belt breaks in the vicinity of the laser sensor, the laser sensor is damaged or the laser beam is blocked by the earth and sand that has fallen from the broken belt.

  The present invention has been made in view of the above circumstances. SUMMARY OF THE INVENTION An object of the present invention is to enable monitoring of belt damage without being interfered with by a powdery substance such as earth and sand falling through a crack or broken portion of the belt.

  In order to solve the above problems, a belt monitoring apparatus according to the present invention includes a belt on which powder particles are placed, a belt that conveys the powder particles, and a laser that faces the belt from the side on which the powder particles are placed. An optical measuring device that projects light and receives reflected light of the laser beam and measures the time difference between the light projecting timing and the light receiving timing, and a crack or breakage of the belt based on the measurement result of the optical measuring device And a determination unit for determining the presence or absence.

  According to the present invention, since there is an optical measuring instrument on the side where the powder is placed, even if the powder placed on the belt falls through a crack or breakage of the belt, the powder is optical. Never hit the measuring instrument. Therefore, damage to the optical measuring device can be prevented. Furthermore, the laser beam emitted by the optical measuring instrument is not shielded by the powder or particles that have fallen from the cracks or breaks of the belt. Therefore, it is possible to determine the presence or absence of cracks or breaks in the belt without being interfered by the powder particles.

  Preferably, the belt monitoring device includes a drive unit that drives the belt, and an emergency stop unit that stops the drive unit when the determination unit determines the presence of a crack or a fracture.

  Therefore, if cracks occur in the belt while the granular material is being transported by the belt, the belt will stop urgently, so safety measures such as belt repair can be taken before the belt breaks or the like. . Even when the belt breaks, the emergency stop of the belt can minimize damage.

  Preferably, the belt monitoring device includes an alarm device and a warning processing unit that activates the alarm device when the determination unit determines the presence of a crack or a fracture.

  Therefore, if cracks or breaks occur in the belt while the granular material is being conveyed by the belt, the alarm is activated, so that an operator or the like can be notified of the occurrence of cracks or breaks.

  Preferably, the optical measuring instrument is a scanning measuring instrument that scans the belt in the width direction with the laser beam.

  Therefore, it is possible to realize cost reduction and downsizing of the apparatus.

  Preferably, the determination unit determines whether or not there is a crack or a fracture by determining whether or not a state in which a measurement result per scan by the scanning type measuring instrument is equal to or greater than a predetermined threshold is continuous. .

The time until the reflected light reflected by the granular material placed on the belt is received by the scanning measuring instrument is shorter than the time until the reflected light reflected by the belt is received by the scanning measuring instrument. Therefore, the measurement result when scanning the granular material with the laser beam is equal to or lower than the detection threshold, and the erroneous detection of the granular material as a crack or a broken portion of the belt can be prevented.
In addition, since it is determined whether or not the state in which the measurement result per scan is equal to or greater than the predetermined threshold value is continuous, it is possible to determine the presence or absence of a long crack in the longitudinal direction of the belt, that is, a vertical tear. Whether the belt is broken or not can also be determined.

  According to the present invention, the belt can be monitored without being interfered by powder particles falling through cracks or breaks in the belt.

It is drawing which showed the belt monitoring apparatus. It is sectional drawing of the belt conveyor seen toward the conveyance direction of a belt. It is the block diagram which showed the belt monitoring apparatus. It is the flowchart which showed the flow of the process of the control unit. It is the graph which showed the measurement result of one scan by the scanning type measuring instrument, when the crack has not passed under the scanning type measuring instrument. It is the graph which showed the measurement result of one scan by the scanning type measuring device, when the crack has passed under the scanning type measuring device.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below are provided with various technically preferable limitations for carrying out the present invention, and the scope of the present invention is not limited to the following embodiments and illustrated examples.

FIG. 1 is a schematic view showing a belt monitoring device 10.
This belt monitoring device 10 monitors the belt 29 during operation of the belt conveyor 20 that conveys earth and sand (powder flow) generated during excavation of the ground, and detects cracks (particularly longitudinal tears) or breakage of the belt 29. To do. The term “longitudinal tear” refers to an elongated crack in the conveying direction of the belt 29. Here, the powder flow means a solid and fluid material, and the powder is also a powder flow.

  This belt monitoring device 10 is employed in a shield method. In the shield construction method, the shield machine 3 is constructed by sequentially advancing the shield machine 1 while excavating the face 2 with the shield machine 1 and assembling the segments behind the shield machine 1. The earth and sand generated by excavation of the face 2 is conveyed to the wellhead 4 of the shield tunnel 3 by the belt conveyor 5. At the wellhead 4, the earth and sand conveyed by the belt conveyor 5 are transferred to the belt conveyor 20, and the earth and sand are carried out by the belt conveyor 20 to the ground through a shaft or the like. Here, the upstream portion of the belt conveyor 20 is arranged below the pulley 6 of the belt conveyor 5, and the sand 7 falls from the belt 7 to the belt 29 of the belt conveyor 20 by the belt 7 of the belt conveyor 5 being folded back by the pulley 6. . Cracks are likely to occur in the belt 29 of the belt conveyor 20 due to the impact force of earth and sand. Therefore, the belt monitoring apparatus 10 monitors the belt 29 on the downstream side of the falling point of earth and sand. The belt monitoring device 10 may be employed in a ground excavation method other than the shield method.

  The belt monitoring device 10 includes a belt conveyor 20, a scanning type measuring device 30, a control unit 50, and an alarm device 70.

-About the belt conveyor 20 The belt conveyor 20 has the pulley 21, the pulley 22, the motor 28, and the belt 29. As shown in FIG. A pulley 21 is provided below the pulley 6 of the belt conveyor 5, and a pulley 22 is provided on the ground. The endless belt 29 is stretched between the pulley 21 and the pulley 22. The motor 28 is driven by a motor driver 28 a and the pulley 22 is rotated by the motor 28. Thereby, the belt 29 circulates and the earth and sand transferred from the belt conveyor 5 to the belt 29 is conveyed from the pulley 21 toward the pulley 22. The pulley 21 may be driven by the motor 28.

Scanning Measuring Device 30 As shown in FIG. 1, the scanning measuring device 30 is disposed above the earth and sand mounting surface (upper surface) of the belt 29 on the downstream side of the pulley 21 and the upstream side of the pulley 22. ing. More specifically, as shown in FIG. 2, the scanning measuring instrument 30 is disposed above the intermediate point in the width direction of the belt 29.

  The scanning measuring instrument 30 is a laser scanner. In other words, the scanning measuring instrument 30 deflects the laser light along the width direction of the belt 29 while projecting the modulating laser light toward the earth and sand mounting surface of the belt 29, and follows the width direction of the belt 29. By receiving the reflected light reflected by each point on the measurement line, the time difference between the laser light projection timing and the reflected light reception timing is measured. Then, the scanning measuring instrument 30 outputs the measurement result to the control unit 50. Here, the laser light irradiation location moves in the width direction of the belt 29 by the deflection of the laser light, and the locus of the laser light irradiation location is called a measurement line.

  Here, since the speed of light is a constant, the time difference between the light projection timing and the light reception timing corresponds to the distance. That is, the scanning measuring instrument 30 measures the distance from each point on the measurement line to the scanning measuring instrument 30 by scanning the laser beam along the width direction of the belt 29.

The scanning measuring instrument 30 includes a light projecting element (for example, a laser diode) that emits laser light, a scanning mechanism that deflects the laser light emitted from the light projecting element in the width direction of the belt 29, and a light receiving element that receives reflected light. And a control circuit that controls the light projecting element, the scanning mechanism, and the light receiving element, and calculates a time difference between the light projecting timing of the light projecting element and the light receiving timing of the light receiving element. The wavelength of the laser light projected by the scanning measuring instrument 30 is not particularly limited, but the laser light is preferably infrared. Since the scanning measuring instrument 30 has a small number of light projecting elements and light receiving elements, the scanning measuring instrument 30 is low-cost and small.
The measurement method using the scanning measuring instrument 30 may be a phase difference measurement method or a pulse measurement method.

  In the present embodiment, the presence or absence of a crack is determined using the measurement result of the scanning measuring instrument 30. Therefore, the measurement result of the scanning type measuring device 30 will be examined. FIG. 5 is a graph showing, in polar coordinates (circular coordinates), the measurement result of one scan when a portion of the belt 29 where no crack exists passes under the scanning measuring instrument 30. FIG. 6 shows the measurement result of one scan in the case where a portion of the belt 29 where the crack exists passes under the scanning type measuring device 30 in polar coordinates. The distance r from the origin O is the measurement time (the time difference between the light projection timing of the light projecting element and the light reception timing of the light receiving element) or the measurement distance (from each point on the locus line of the laser light irradiation point to the scanning type measuring device 30. Distance), and the central angle θ at the origin O represents the direction of laser light projection. As shown in FIG. 5, when a portion of the belt 29 that does not have a crack passes under the scanning measuring instrument 30, the measurement time is almost the same for any light projection direction. On the other hand, when the part where the crack exists in the belt 29 passes under the scanning type measuring instrument 30, the laser light is cracked and reflected at the tip, so that the laser beam is directed toward the crack as shown in FIG. The measurement time by the light projection is extremely longer than the measurement time by the light projection toward the surface of the belt 29 other than the crack. Therefore, the presence or absence of a crack can be determined by comparing the measurement result of the scanning measuring instrument 30 with a predetermined threshold value. Here, the predetermined threshold value is obtained in advance by experiments or the like, and takes into account the unevenness, bending, bending, etc. of the belt 29, and the measurement time shown in FIG. 5 (toward the surface of the belt 29 other than the crack). (Measurement time by light projection) is set slightly longer.

  When earth and sand are placed on the belt 29, the laser beam is reflected on the surface of the earth and sand. The distance from the earth and sand surface to the scanning measuring instrument 30 is the distance from the earth and sand mounting surface of the belt 29 to the scanning measuring instrument 30. Shorter than. In addition, the measurement time when the laser light is reflected on the surface of the earth and sand is less than the above-mentioned predetermined threshold value. Therefore, it is possible to prevent earth and sand from being erroneously detected as cracks in the belt 29.

Further, since the earth and sand placed on the belt 29 falls from the belt 29 through the crack, the crack is not blocked by the earth and sand. Therefore, a crack generated in the belt 29 can be reliably detected.
Even if the earth and sand are filled in the cracks, the surface of the earth and sand tends to be depressed more than the surface of the belt 29 due to the weight of the earth and sand. Therefore, a crack can be detected.
Moreover, since the scanning type measuring device 30 is provided above the belt 29, it is possible to prevent the earth and sand that has fallen through the crack from colliding with the scanning type measuring device 30.

Here, below the position where the scanning measuring instrument 30 is disposed, both edge portions of the belt 29 are supported from below by the rollers 24 and 25, and the central portion of the belt 29 is bent by its own weight. When the crack generated in the belt 29 passes under the scanning type measuring device 30, the width of the crack generated in the belt 29 widens due to the bending of the belt 29, and the earth and sand on the belt 29 falls through the crack. It has become easier. Therefore, the crack is not blocked by the earth and sand, and the detection failure of the crack can be prevented.
A plurality of rollers may be used instead of the rollers 24 and 25. Specifically, a plurality of rotatable rollers are arranged from the pulley 21 to the pulley 22 at intervals along the conveying direction of the belt 29, and the earth and sand mounting surface of the belt 29 is supported by these rollers from below. And the scanning type measuring device 30 is arrange | positioned above between adjacent rollers, and the locus | trajectory (measurement line) of the irradiation place of the laser beam by the scanning type measuring device 30 exists between adjacent rollers. Since the belt 29 bends slightly between these rollers, cracks generated in the belt 29 are likely to spread, and earth and sand are also likely to fall through the cracks.

-Alarm 70 As shown in FIG. 1, the alarm 70 is provided in the vicinity of the belt conveyor 20 or in the shield tunnel 3. The alarm device 70 is a warning light, a warning indicator, or a warning speaker.

Control Unit 50 FIG. 3 is a block diagram showing the configuration of the belt monitoring device 10.
The control unit 50 is a computer having a CPU, GPU, ROM, RAM, hardware interface, and the like. In addition to the alarm device 70, the scanning type measuring device 30 and the motor driver 28 a, an operation unit 51, a storage unit 52 and a display unit 53 are connected to the control unit 50.

The operation unit 51 is an input device such as a switch, a keyboard, or a pointing device.
The storage unit 52 is a storage device including a semiconductor memory or a hard disk drive. The storage unit 52 is readable and writable by the control unit 50.
The display unit 53 is a display that performs screen display.

  The storage unit 52 stores a program 52 a that can be executed by the control unit 50. The program 52a may be stored in the ROM of the control unit 50.

Processing and function of the control unit 50 The processing executed by the control unit 50 based on the program 52a during the operation of the belt conveyor 20, that is, when the motor 28 is driven by the motor driver 28a, will be specifically described below. .

  The program 52a causes the control unit 50 to execute measurement result input processing, and the control unit 50 functions as a measurement result input unit. That is, when the control unit 50 controls the scanning type measuring instrument 30, the earth and sand mounting surface of the belt 29 is scanned along the measuring line by the scanning type measuring instrument 30, and the measurement results (measurement time, measuring distance) of each point on the measuring line are scanned. ) Are sequentially output by the scanning type measuring device 30, and the control unit 50 sequentially inputs the measurement results.

  The program 52a causes the control unit 50 to execute damage determination processing, and the control unit 50 functions as a damage determination unit. That is, the control unit 50 determines the presence or absence of a crack in the belt 29 based on the measurement results sequentially input from the scanning type measuring device 30. Specifically, the process shown in FIG. 4 is executed by the control unit 50.

  First, the control unit 50 sets a counter N for managing the crack length along the conveying direction of the belt 29 to a predetermined initial value (for example, N = 1) (step S1). This counter initial setting process is performed immediately before the motor 28 starts operating or immediately before the scanning type measuring instrument 30 starts measuring.

  Next, the control unit 50 is in the middle of one scanning by the scanning measuring instrument 30 (from the time when laser light is projected on one edge of the belt 29 until the time when laser light is projected on the other edge. In the meantime, the measurement results sequentially input from the scanning type measuring device 30 are compared with the above-mentioned predetermined threshold (step S2).

  As a result of the comparison, when the sequentially input measurement result is equal to or greater than the predetermined threshold value continuously for a predetermined number of times (for example, 3 times) (step S3: YES), 1 is added to the counter N (step S4). Here, the predetermined number of times corresponds to the width of the crack to be detected. That is, if the belt 29 is cracked, the laser beam passes through the crack, so that the measurement result is a predetermined threshold value, and if the width of the crack generated in the belt 29 is wider than the predetermined value, the measurement is sequentially input. The result becomes a predetermined threshold value or more continuously for a predetermined number of times. In addition, there is a possibility that the measurement result may become a predetermined threshold value or more due to noise, disturbance or the like even though no crack is generated in the belt 29. In such a case, in order to prevent erroneous detection of the crack, sequentially A crack is detected based on whether or not the input measurement result has continuously exceeded a predetermined threshold value a predetermined number of times (see step S2 and step S3).

  On the other hand, as a result of the comparison, when the sequentially input measurement results do not continuously exceed the predetermined threshold value a predetermined number of times (step S3: NO), the control unit 50 sets the counter N to a predetermined initial value (for example, N = 1) (step S5), and the process of the control unit 50 returns to step S2. Therefore, the measurement result is sequentially compared with the predetermined threshold value by the control unit 50 even during the next scanning by the scanning measuring instrument 30 (step S2).

  After step S4, the control unit 50 compares the counter N with a predetermined value M (step S6). As a result of the comparison, when the counter N is less than the predetermined value M (step S6: NO), the process of the control unit 50 returns to step S2. Therefore, the measurement result is sequentially compared with the predetermined threshold value by the control unit 50 even during the next scanning by the scanning measuring instrument 30 (step S2). On the other hand, as a result of the comparison, if the counter N is greater than or equal to the predetermined value M (step S6: YES), the control unit 50 executes a warning process and an emergency stop process described later (step S7).

  As described above, when the crack generated in the belt 29 passes under the scanning type measuring instrument 30, the processing of Step S2, Step S3, Step S4, and Step S6 is repeated, so that the counter N is added. To go. If the crack is long, it takes a long time for the crack to pass under the scanning type measuring instrument 30, so that the counter N becomes equal to or greater than the predetermined value M. Then, a warning process and an emergency stop process described later are executed by the control unit 50. The predetermined value M is set in advance based on the length of the crack to be detected, the traveling speed of the belt 29, the scanning frequency of the scanning type measuring instrument 30, and the like.

  By the way, when the earth and sand fall from the belt 7 of the belt conveyor 5 to the belt 29 of the belt conveyor 20, the belt 29 may be broken. The presence or absence of such breakage can also be determined by the damage determination process of the control unit 50. That is, when the belt 29 is broken, the belt 29 does not pass below the scanning type measuring instrument 30, so that the sequentially input measurement result during each scan becomes a predetermined threshold value or more continuously for a predetermined number of times (step S3: YES). ). In addition, since the state in which the belt 29 does not pass the lower side of the scanning type measuring instrument 30 continues, the processes of Step S2, Step S3, Step S4 and Step S6 are repeated, and the counter N is added. For this reason, the counter N becomes equal to or greater than the predetermined value M, and a warning process and an emergency stop process described later are executed by the control unit 50.

  The program 52a causes the control unit 50 to execute warning processing, and the control unit 50 functions as a warning processing unit. That is, when the counter N is equal to or greater than the predetermined value M, the control unit 50 activates the alarm device 70. Then, if the alarm device 70 is a warning light, the alarm device 70 is lit or blinking. If the alarm device 70 is an alarm speaker, a warning sound is emitted from the alarm device 70, and the alarm device 70 is a warning indicator. In this case, a warning is displayed by the alarm device 70. Thereby, a warning can be alert | reported to an operator, and an operator can recognize presence of the crack of the belt 29 and generation | occurrence | production of a fracture | rupture.

  Further, the program 52a causes the control unit 50 to execute an emergency stop process, and the control unit 50 functions as an emergency stop unit. That is, if the counter N is equal to or greater than the predetermined value M, the control unit 50 turns off the motor driver 28a and stops the motor 28. Thereby, the belt conveyor 20 stops.

  As mentioned above, although the form for implementing this invention was demonstrated, the said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and equivalents thereof are also included in the present invention.

  In the above embodiment, the optical measuring instrument is the scanning measuring instrument 30, but a line measuring instrument may be provided above the belt 29 instead of the scanning measuring instrument 30. The line-shaped measuring device includes a plurality of laser projectors arranged along the width direction above the belt 29, a plurality of light receivers arranged along the width direction above the belt 29, and the laser projector and the plurality of laser projectors. And a control circuit for controlling the light receiver. The laser projector and the light receiver form a one-to-one pair, each set of laser projectors projects laser light toward the belt 29, and the light reflected from the surface of the belt 29 is received by each set of light receivers. The time difference between the projection timing of each set of laser light and the reception timing of reflected light is calculated by the control circuit. The measurement results of one line based on the light received by these light receivers are latched in the control circuit of the line-shaped measuring device, and these measurement results are sequentially output to the control unit 50. Therefore, the process shown in FIG. Is judged. Here, the measurement result of one line of the linear measuring instrument corresponds to the measurement result of one scan of the scanning type measuring instrument 30.

  DESCRIPTION OF SYMBOLS 1 ... Shield machine, 2 ... Face, 3 ... Shield tunnel, 4 ... Wellhead, 5 ... Belt conveyor, 6 ... Pulley, 7 ... Belt, 10 ... Belt monitoring device, 20 ... Belt conveyor, 21 ... Pulley, 22 ... Pulley, 24 ... Roller, 25 ... Roller, 28 ... Motor (drive unit), 28a ... Motor driver, 29 ... Belt, 30 ... Scanning type measuring instrument (optical measuring instrument), 50 ... Control unit (determination unit, emergency stop unit, Warning processing unit), 51 ... operation unit, 52 ... storage unit, 52a ... program, 53 ... display unit, 70 ... alarm device

Claims (5)

A belt on which the powder is placed and transports the powder;
An optical measuring instrument that projects laser light toward the belt from the side on which the powder is placed, receives reflected light of the laser light, and measures the time difference between the light projection timing and the light reception timing;
A belt monitoring device comprising: a determination unit that determines whether the belt is cracked or broken based on a measurement result of the optical measuring instrument. A drive unit for driving the belt;
The belt monitoring apparatus according to claim 1, further comprising an emergency stop unit that stops the drive unit when the determination unit determines the presence of a crack or a fracture. An alarm,
The belt monitoring apparatus according to claim 1, further comprising: a warning processing unit that activates the alarm when the determination unit determines the presence of a crack or a fracture.   4. The belt monitoring apparatus according to claim 1, wherein the optical measuring instrument is a scanning measuring instrument that scans the belt in the width direction with the laser beam. 5.   The determination unit determines whether or not there is a crack or fracture by determining whether or not a state in which a measurement result per scan by the scanning type measuring instrument is equal to or greater than a detection threshold is continuous. The belt monitoring device according to claim 4, wherein

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