Wire rope inspection method and inspection device

Abstract

To provide an inspection method and an inspection apparatus for a bare wire broken state of a wire rope by detecting a timing when a force is applied to the wire rope.SOLUTION: An integrated value of acoustic emission (AE) energy of a wire rope 4 is used for inspecting a bare wire broken state of the wire rope 4. The integrated value of AE energy is the integrated value from the first timing at which a tension starts to act on the wire rope 4 to the second timing at which the wire rope 4 starts to move a load 5 at the end until a predetermined time elapses. A vibration acceleration sensor 3 is used for detecting the timing (first timing) at which a tension starts to act on the wire rope 4 and the timing (second timing) at which the wire rope 4 starts to move the load 5 at the end portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for inspecting wire ropes for broken wires, and more particularly to a technique for diagnosing the soundness of wire ropes in hydraulic facilities such as spillway gates. [Background technology]

[0002] It is important to monitor the condition of wire ropes used to lift loads such as elevators so that damage can be detected early. Known technologies include a technique for monitoring wire rope damage by automatically checking the number of friction feet and broken wires based on photographed images of the wire rope (see, for example, Patent Document 1), and a technique for monitoring wire rope damage using an acoustic emission (AE) method that detects acoustic signals and vibrations generated when broken wires come into contact with a detection element in elevator wire ropes (see, for example, Patent Document 2).

[0003] Wire ropes are also used in power facilities, for example, at dams in hydroelectric power plants to open and close dam gates. For example, the wire ropes for spillway gates are installed underwater within the dam's reservoir, and currently, to ensure their integrity, divers inspect them once every three years if they have been installed for less than 15 years, and once a year if they have been installed for more than 15 years, to check for broken wires in the wire rope, and replace any wire rope with a wire breakage rate of 10% or more.

[0004] However, inspections by divers pose the risk of accidents during diving work, such as the possibility that a diver could accidentally be sucked into the discharge from the spillway gate. There are legal restrictions on the amount of time a diver can work underwater, and moving between gates also requires moving diving equipment, which reduces work efficiency. Furthermore, diver labor costs are high, and the greater the number of spillway gates, the greater the number of inspection days, which increases inspection costs. Furthermore, securing sufficient divers is difficult, making it difficult to coordinate work schedules. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-012903 [Patent Document 2] International Publication No. 2011 / 158871 Summary of the Invention [Problem to be solved by the invention]

[0006] In the aforementioned Patent Document 2, the AE method is used to detect acoustic signals and vibrations of a detection member generated when a broken wire in the wire rope comes into contact with the detection member, thereby monitoring damage to the wire rope. An acoustic emission (AE) sensor that detects high-frequency components of the vibrations of the detection member is used as the detection sensor. In the technology of Patent Document 2, damage or breakage of the wire in an elevator wire rope is likely to occur first at the outer position where the wire rope is pulled most strongly when the wire rope is bent, for example, when it is wound around the hoist drum or hoist car of a hoisting machine. Therefore, AE sensors are placed at points where the wire rope bends to detect damage or breakage early.

[0007] However, there is no known technology that can detect a wire break in a wire rope by capturing the timing at which force is applied to the wire rope, rather than detecting when the wire rope reaches the hoist. Furthermore, there is a need for a safe, highly accurate diagnosis of a wire break in wire ropes that require underwater inspection, such as wire ropes for spillway gates in dam facilities, and for early detection of damage or breakage.

[0008] In view of the above circumstances, the present invention aims to provide a method and an apparatus for inspecting a wire rope for broken wires by detecting the timing when force is applied to the wire rope. [Means for solving the problem]

[0009] In order to solve the above problem, the inspection method of the present invention inspects the wire rope for broken wires using the integrated value of the acoustic emission (AE) energy of the wire rope. Calculating the integrated value of AE energy means detecting the elastic waves (AE waves) generated when the wires of a wire rope are frictioned, converting them into an electrical signal, obtaining an AE waveform that represents the magnitude of the AE wave as, for example, a change in voltage value over time, and then calculating the integrated value of AE energy, which is the integral value of the AE waveform. Rather than simply measuring the AE waves of the wire rope, damage or breakage can be detected early by capturing the timing at which force is applied to the wire rope and calculating the integrated value of AE energy from the moment the wire rope starts to move the load at its end until a specified time has passed. Here, the wire rope broadly includes wire ropes that require inspection for broken wires, such as wire ropes used to suspend elevator cars or loads from cranes, and wire ropes for spillway gates in dam facilities.

[0010] In the inspection method of the present invention, the integrated value of the AE energy is calculated from the first timing when tension starts to act on the wire rope to the second timing when the wire rope starts to move the load at the end. After detecting This is the integrated value up to the elapse of a predetermined time. Because the rise in AE energy can be seen not only from the first timing to the second timing, but also after the second timing, highly accurate inspections are possible by using the integrated value from the second timing until a specified time has elapsed. In other words, the first timing (when force is applied to the wire rope) is taken as the timing when AE energy begins, and the specified time has elapsed since the second timing (when the wire rope begins to move the load at its end) is taken as the timing when AE energy is released. The predetermined time is preferably 0.0 to 2.0 seconds, more preferably 0.5 to 1.5 seconds, and even more preferably 0.8 to 1.2 seconds.

[0011] In the inspection method of the present invention, the first and second times are preferably response times of an acceleration sensor (hereinafter also referred to as a vibration acceleration sensor) that detects vibration acceleration. The vibration acceleration sensor is attached to a load moved by a wire rope, and responds when tension begins to act on the wire rope (first time) and when the wire rope begins to move the load at its end (second time). For example, when inspecting a wire rope for a spillway gate for a broken wire, the vibration acceleration sensor is attached to the spillway gate. In the case of a spillway gate, the vibration acceleration sensor can detect the first and second times even when water is accumulated in the dam reservoir. The vibration acceleration sensor is used to detect the elongation of the wire rope. If the weight of the load and the length of the wire rope when moving it are known in advance, it is possible to measure the load on the wire rope, the wire rope's elongation rate, the wire rope's length, etc. and determine the timing. Here, in the case of a single-axis acceleration sensor, the vibration acceleration sensor is placed so that its detection axis is perpendicular to the surface on which the load is placed, and the vibration of the load is detected as an acceleration (m / s 2The vibration acceleration sensor may be, for example, a two-axis or three-axis acceleration sensor. The type of acceleration sensor may be selected arbitrarily, for example, from a capacitance type, a piezo-resistance type, or the like.

[0012] In the inspection method of the present invention, the wire rope's wire breakage condition is preferably determined such that the correlation coefficient between the damage rate and the integrated value of AE energy is 0.8 or more. For example, in the case of wire ropes for spillway gates, on-site verification data has revealed that there is a high correlation between the AE energy generated by wire breakage and the actual inspection results (wire breakage rate) performed by divers.

[0013] Next, the inspection device of the present invention will be described. The inspection device of the present invention calculates the integrated value of the acoustic emission (AE) energy of the wire rope to inspect the wire rope for broken wires. Specifically, the inspection device of the present invention comprises the following components 1) to 3). 1) AE wave input unit that inputs AE wave signals from the AE sensor attached to the wire rope. 2) A vibration acceleration input unit that inputs vibration acceleration from an acceleration sensor that detects vibration acceleration and is installed on the load connected to the end of the wire rope. 3) Based on the vibration acceleration input from the vibration acceleration input unit, the first timing when tension begins to act on the wire rope and the second timing when the load begins to move are detected, and the first timing is converted into the second timing. After detecting A determination unit that calculates the integrated value of the AE energy of the AE wave of the wire rope input from the AE wave input unit over a predetermined time period and determines whether the wire rope is broken.

[0014] In the inspection device of the present invention, it is preferable that the judgment unit classifies the wire breakage state of the wire rope into ranks of whether replacement is necessary. For example, it can be displayed in three ranks: replacement necessary, caution required, and no replacement necessary. The judgment result ranks can be displayed in colors such as blue, yellow, and red to make them easy for the user to understand.

[0015] In the inspection device of the present invention, it is preferable that the AE sensors are attached to two locations, one above and one below, the lower end of the hoist drum, and the determination unit removes the AE waves generated on the hoist drum side when calculating the integrated value of the AE energy of the AE waves of the wire rope. By removing the AE waves generated on the hoist drum side as noise, the measurement accuracy of the AE energy is improved.

[0016] In the inspection method and inspection device of the present invention, it is preferable that the wire rope is a wire rope for a spillway gate installed at a dam. A spillway gate is a general term for discharge equipment installed to ensure the safety of a dam and reservoir against the inflow of floodwaters, and is also called a spillway in the case of a power-generating dam. [Effects of the Invention]

[0017] The inspection device and inspection method for the broken wire condition of a wire rope of the present invention have the effect of detecting the timing when force is applied to the wire rope, inspecting the broken wire condition of the wire rope, and determining the degree of damage to the wire rope early, efficiently, and safely. [Brief explanation of the drawings]

[0018] [Figure 1] Inspection system functional block diagram [Figure 2] Connection diagram of the inspection system in use [Figure 3] Diagram of wire rope for spillway gates in dam facilities [Figure 4] Inspection method flow chart [Figure 5] Flowchart for determining the wire rope wire breakage [Figure 6] AE measurement of wire rope [Figure 7] Wire rope structure diagram [Figure 8] Diagram of the mechanism for measuring AE energy using a vibration acceleration sensor (1) [Figure 9] Diagram of the mechanism for measuring AE energy using a vibration acceleration sensor (2) [Figure 10] On-site measurement data (sites with few AE wave measurements) [Figure 11] On-site measurement data (sites with many AE wave measurements) [Figure 12] Graph showing the correlation between integrated AE energy value and wire breakage rate (single strand damage rate) DETAILED DESCRIPTION OF THE INVENTION

[0019] An example of an embodiment of the present invention will be described in detail below with reference to the drawings. Note that the scope of the present invention is not limited to the following examples and illustrated examples, and many modifications and variations are possible. [Example]

[0020] The embodiment of the present invention will be described assuming that the load connected to the wire rope is a spillway gate of a dam. The load may include an elevator car, a heavy load suspended by a crane, or any other object suspended or moved by a wire rope. First, a functional block diagram of an inspection system according to one embodiment of the present invention will be described with reference to Figures 1 to 3. The inspection system 10 comprises an inspection device 1, an AE sensor 2, and a vibration acceleration sensor 3. One end of a wire rope 4 to be inspected is attached to a spillway gate 5 (load) of a dam, and the other end is wound around a hoist 6, and the opening and closing of the spillway gate is controlled by controlling the hoist 6.

[0021] The AE sensor 2 detects elastic waves (AE waves) generated when the metals that make up the wire rope rub against each other when the wire rope deforms and breaks, and is attached to the surface of the wire rope. There are no particular restrictions on the attachment method, and the sensor can be fixed with tape or the like. The AE sensor 2 detects the AE waves, converts them into electrical signals, and sends the detected signal data to the inspection device 1.

[0022] The vibration acceleration sensor 3 is attached and fixed to the spillway gate 5. Specifically, the vibration acceleration sensor 3 is an acceleration sensor that detects vibration acceleration, and in the case of a uniaxial acceleration sensor, it is positioned so that its detection axis is perpendicular to the installation surface of the spillway gate 5. The vibration acceleration sensor 3 detects the vibration of the spillway gate 5 as acceleration in the detection axis direction, and sends the detected signal data to the inspection device 1.

[0023] In the inspection device 1, an AE wave signal from the AE sensor 2 attached to the wire rope 4 is input through an AE wave input unit 12. In addition, vibration acceleration is input through a vibration acceleration input unit 13 from an acceleration sensor that detects vibration acceleration and is installed on the spillway gate 5. The AE wave signal data input through the AE wave input unit 12 and the vibration acceleration signal data input through the vibration acceleration input unit 13 are calculated in a determination unit 14 of the inspection device 1. Here, the inspection device 1 may be an inspection device such as a portable computer or a personal computer. The functions of the inspection device (AE wave input unit 12, vibration acceleration input unit 13, and determination unit 14) may be realized, for example, by a microprocessor (e.g., a CPU) reading and executing a program stored in a memory. Alternatively, they may be realized by hardware such as a dedicated circuit, or by a combination of software and hardware. Furthermore, some of the functions of the inspection device 1 (e.g., a separate function of the determination unit 14) may be realized by another computer that can communicate with the inspection device 1.

[0024] The determination unit 14 is composed of a first timing detection unit 14a, a second timing detection unit 14b, an AE energy integrated value calculation unit 14c, a wire break state determination unit 14d, and a determination result display unit 14e. The first timing detection unit 14a detects the first timing at which tension begins to act on the wire rope 4 based on the vibration acceleration input from the vibration acceleration input unit 13, and sends a detection signal to the AE energy integrated value calculation unit 14c and the second timing detection unit 14b. After detecting the first timing, the second timing detection unit 14b detects the second timing at which the wire rope 4 begins to move the spillway gate, and sends a detection signal to the AE energy integrated value calculation unit 14c. The AE energy integrated value calculation unit 14c calculates the integral value of the AE waveform acquired from the AE wave input unit 12 from the first timing, and calculates the integral value of the AE waveform from the second timing until a predetermined time has elapsed (here, one second has elapsed) as the integrated value of the AE energy. Then, the wire breakage state determination unit 14d determines the wire breakage state of the wire rope 4 using the integrated value of AE energy calculated by the AE energy integrated value calculation unit 14c. The determination result display unit 14e displays the wire breakage state on the inspection device 1, for example, by displaying it in a color-coded lamp or on a display. The determination results are displayed according to the rank of necessity for replacement, and more specifically, are displayed in three ranks: replacement required, caution required, and no replacement required. The ranks of the determination results are displayed in an easy-to-understand manner for the user, for example, by color-coding the ranks as blue for no replacement required, yellow for caution required, and red for replacement required. The determination results can be not only displayed but also recorded.

[0025] FIG. 2 shows the connections of the components of the inspection system 10 when in use. The AE sensor 2 contacts the wire rope 4, and the vibration acceleration sensor 3 is mounted on the spillway gate 5. As described above, the vibration acceleration sensor 3 is positioned so that its detection axis is perpendicular to the installation surface of the spillway gate 5. When a wire break 7 occurs in the wire rope 4, an AE wave (rubbing noise) 8 is generated. The AE sensor 2 detects this AE wave 8 and converts it into an electrical signal (e.g., a voltage value). The AE sensor 2 is connected to the inspection device 1 via a signal cable 2a. The converted AE wave is sent to the AE wave input unit 12 of the inspection device 1. The inspection device 1 acquires the change in the magnitude (voltage value) of the AE wave over time. The vibration acceleration sensor 3 is connected to the inspection device 1 via a signal cable 3a. The acceleration in the detection axis direction during the vibration of the spillway gate 5 is sent to the vibration acceleration input unit 13 of the inspection device 1. The inspection device 1 acquires first and second timings based on the timing at which the vibration acceleration increases.

[0026] Figure 3 shows a wire rope for a spillway gate in a dam facility. Water is stored in the dam reservoir 20, and the spillway gate 5 is opened and closed and the flow rate is adjusted by controlling a hoist 6 to operate the spillway gate wire rope 4. Conventionally, a diver would dive into the dam reservoir 20 to check for damage to the wire rope 4. In the inspection system 10, a working space is secured on the side of the hoisting machine 6 where the AE sensor 2 can be installed, and the state of wire breakage in the wire rope for the spillway gate from the air to the underwater portion is inspected. If there is a break in the wire rope 4 for the spillway gate, the wire moves and is more likely to rub due to tension when the gate operates, and AE waves are generated that are larger and longer than when the wire rope is not broken. Therefore, the state of damage to the wire rope 4 can be confirmed by capturing the AE waves.

[0027] Next, the flow of the inspection method will be described with reference to Fig. 4. As shown in Fig. 2, with the inspection device 1, AE sensor 2, vibration acceleration sensor 3, and wire rope 4 connected to each other, an AE wave signal is input from the AE sensor 2 (step S01), and vibration acceleration is input from the vibration acceleration sensor 3 (step S02). Steps S01 and S02 are listed in order, but they may be reversed, and the AE sensor 2 and vibration acceleration sensor 3 are separate sensors and can be performed simultaneously. Based on the vibration acceleration from the vibration acceleration sensor 3, it is determined whether a first timing has been detected, at which tension begins to act on the wire rope 4 (step S03). When the first timing is detected, integration of the AE waveform is started, and AE energy accumulation is started (step S04). Then, based on the vibration acceleration from the vibration acceleration sensor 3, it is determined whether a second timing has been detected, at which the wire rope 4 begins to move the spillway gate (step S05). After detecting the second timing, it waits until a predetermined time (e.g., 1 second) has elapsed (step S06), and then the accumulation of AE energy is terminated (step S07). The accumulated value of AE energy is calculated (step S08), and a wire break state of the wire rope is determined (step S09), and the process ends.

[0028] Figure 5 shows an example of a flow for determining the wire breakage status of a wire rope. The necessity for replacement is ranked according to the integrated value of AE energy. The correlation between the integrated value of AE energy and the wire breakage rate (referred to as the single-strand damage rate) will be explained later. For example, if the integrated value of AE energy is less than 90 (#1), the wire breakage rate is less than 5%, a blue light is displayed, and the wire rope is determined to be "no replacement required" (S12, S15). Also, if the integrated value of AE energy is 90 or more but less than 160 (#2), the wire breakage rate is 5% or more but less than 10%, a yellow light is displayed, and the wire rope is determined to be "caution required" (S13, S16). If the integrated value of AE energy is 160 or more (#3), the wire breakage rate is 10% or more, a red light is displayed, and the wire rope is determined to be "replacement required" (S14, S17).

[0029] AE measurement of a wire rope will be explained with reference to Figure 6. Figures 6(1) and 6(2) are schematic illustrations of AE wave generation when the wire rope has no broken wires. Meanwhile, Figures 6(3) and 6(4) are schematic illustrations of AE wave generation when the wire rope has a broken wire. Figures 6(1) and 6(3) are both images of the wire rope 4 when no force is applied, while Figures 6(2) and 6(4) are images of the wire rope 4 when tension is applied. When tension is applied, the wire rope is pulled in the direction of the arrow in the figure, extending its length compared to when it is unloaded. As shown in Figure 6(2), when the wire rope has no broken wires, AE wave (rubbing noise) 11a is small and short. However, as shown in Figure 6(4), when the wire rope has broken wires, AE waves (rubbing noise) 11b and 11c are large and long.

[0030] Here, we will explain the structure of an example of a wire rope, such as a 6x37 (Japanese Industrial Standards: JIS) wire rope for ships, cranes, machinery, and other general uses, with reference to Figure 7. Wire ropes are complex structures made up of numerous wires, and there are various types depending on the core rope 4a (either fiber core or rope core), the number and shape of strands 4b surrounding the core rope 4a, and the number and arrangement of wires 4c within the strands 4b. For example, a 6x37 wire rope is constructed as shown in Figure 7, with six strands 4b, each consisting of 37 wires 4c, twisted around the core rope 4a at a predetermined pitch. In Figure 7(1), (1) shows the structure of a 6x37 wire rope, and (2) shows the cross section of the wire rope. In Figure 7(1), one pitch of the wire rope is shown as a one-lay length of 4d. Wire breaks within this one-lay length are checked to determine whether the wire rope needs to be replaced. For example, if there are no broken wires within the one-lay length, it can be determined that there is no abnormality. Furthermore, if the ratio of the number of broken wires to the total number of wires (6 x 37 = 222) in one strand length is defined as the "damage rate," then if the number of broken wires in one strand length is 22, the damage rate will be 10%. For example, if the damage rate is 10% or more, it can be determined that the wire rope has a deterioration rank that directly leads to a malfunction that will stop functioning or cause damage.

[0031] Conventionally, deterioration diagnosis has been carried out by visual inspection by people including divers or by images of the wire rope. However, by using the correlation between the damage rate within one twist length and the integrated value of AE energy, the inspection device 1 described above can determine the state of broken wires in the wire rope using the integrated value of AE energy, thereby reducing the risk of accidents and improving inspection efficiency (reducing inspection costs).

[0032] Figures 8 and 9 show how AE energy is measured using a vibration acceleration sensor. In Figure 8, the vertical axis of the upper graph represents AE energy (S·V), and the vertical axis of the lower graph represents vibration acceleration (V), with both axes representing time (s). AE energy is calculated from the vibration acceleration measured by the vibration acceleration sensor and the AE waves measured by the AE sensor. By comparing this vibration acceleration and AE energy, the point at which tension is applied to the wire rope is identified, which is the start timing of AE energy (timing 1). After timing 1, further force is applied to the wire rope, causing it to tighten and lengthen. With the vibration acceleration sensor, when tension begins to be applied to the wire rope, the end of the wire rope moves, vibrating the load, causing an increase in acceleration. Next, acceleration also increases at the point at which the wire rope begins to move the load (timing 2). AE energy continues to increase after timing 2 and then stabilizes (when the wire rope is fully extended). The time it continues to increase after timing 2 is approximately 1 second. There are two times, a first time and a second time, when the vibration acceleration measured by the vibration acceleration sensor suddenly increases, and the AE energy continues to increase after the second time until a predetermined time has elapsed.

[0033] The integrated value of AE energy is calculated from the first point in time when tension begins to be applied to the wire rope, causing the end of the wire rope to move and vibrate the load, to the second point in time (after a predetermined time has passed) when the end of the wire rope begins to move and vibrate the load, and the wire rope wire breakage status is determined.Here, AE energy is calculated as the product of time (S) and the voltage (V) into which the AE wave is converted by the AE sensor. When a spillway gate is operated by a wire rope, as shown in Figure 9, the gate body and the socket at the end of the wire rope are not in contact when the gate is fully closed, but when the gate is opened, tension in the wire rope causes the socket to come into contact with the gate body, and the first timing (starting point) is detected from the vibration acceleration at that time. After that, the timing when the spillway gate opens (discharge start timing) is captured when a certain amount of time has passed from the second timing (ending point), and the integration of AE energy ends. Between the starting point and the ending point, in addition to standing waves caused by the natural vibration of the wire rope and steady energy generated by the environment (wind, waves), etc., AE energy due to wire breakage is added.

[0034] Figure 10 shows an example of measurement data from a spillway gate site. At this site, an inspection by a diver revealed that there were no broken wires in the wire rope. The graph in Figure 10(1) shows that there were few measurement points for the amplitude (dB) of the AE waves captured by the AE sensor. Furthermore, the graph in Figure 10(2) shows that when the integrated value of AE energy was calculated from the first and second timings at which vibration acceleration was captured and the specified elapsed time, the value was small.

[0035] On the other hand, Figure 11 shows measurement data from another spillway gate site. At this site, an inspection by a diver found that 28 wires in the wire rope had broken. However, according to the graph in Figure 11(1), there were many measurement points for the amplitude (dB) of the AE waves captured by the AE sensor. Also, according to the graph in Figure 11(2), when the integrated value of the AE energy was calculated from the first and second timings at which the vibration acceleration was captured and the specified elapsed time, a large value was obtained.

[0036] Regarding the correlation between the integrated value of AE energy (also called integrated AE energy) and the single-strand damage rate, which is an indicator of the wire breakage status of a wire rope, we investigated the integrated AE energy value against the single-strand damage rate (caused by divers' inspection work) of wire ropes attached to spillway gates (17 gates) at dam sites (7 locations) shown in Table 1 below, and confirmed the correlation between the two variables. As shown in Table 1, the wire ropes were two types (6x37, 6x61) with different wire diameters (mm), and the correlation between integrated AE energy and single-strand damage rate was confirmed for a total of 40 wire ropes. In addition, in all cases, an increase in AE energy was confirmed around 1 second from the second timing. Figure 12 shows the correlation between the cumulative AE energy and the single-thread damage rate. From Figure 12, there is a positive correlation between the two variables, cumulative AE energy (S·V) and the single-thread damage rate (%), with a correlation coefficient R of 0.87 (coefficient of determination R 2 =0.7584), indicating a high correlation.

[0037] [Table 1]

[0038] As described above, according to the wire rope inspection device and inspection method of the present invention, the first timing (the timing when tension begins to act on the wire rope) to the second timing (the timing when the wire rope begins to move the load at the end) After detecting Furthermore, the state of wire rope wire breakage can be determined using the correlation between the cumulative AE energy over a specified time period and the single-strand damage rate.The correlation coefficient between the cumulative AE energy and the single-strand damage rate was R = 0.87, confirming a high correlation. [Industrial Applicability]

[0039] The present invention is useful for inspecting wire ropes for spillway gates, which are currently inspected by divers. [Explanation of symbols]

[0040] 1. Inspection equipment 2 Acoustic Emission (AE) Sensors 3. Vibration acceleration sensor 2a, 3a signal cable 4 Wire rope 5 Spillway Gate 6 Hoisting machine 7. Wire break 8 AE waves (rubbing noise) 10 Inspection System 12 AE wave input section 13 Vibration acceleration input section 14 Judgment section 20 Dam reservoir

Claims

1. An inspection method for inspecting a wire rope for a broken wire using an integrated value of acoustic emission (AE) energy of the wire rope, comprising: An inspection method characterized in that the integrated value of the AE energy is the integrated value from the first timing when the end of the wire rope moves and vibrates the load as tension begins to act on the wire rope, to the elapse of a predetermined time after detecting the second timing when the wire rope begins to move the load at the end.

2. 2. The inspection method according to claim 1, wherein the first timing and the second timing are response timings of an acceleration sensor that detects vibration acceleration.

3. 2. The inspection method according to claim 1, wherein the wire breakage state of the wire rope is determined by a correlation coefficient of the damage rate with the integrated value of the AE energy of 0.8 or more.

4. 4. The inspection method according to claim 1, wherein the wire rope is a wire rope for a spillway gate installed in a dam.

5. An inspection device that calculates an integrated value of acoustic emission (AE) energy of a wire rope and inspects the wire rope for broken wires, The inspection device includes: an AE wave input unit that inputs an AE wave signal from an AE sensor attached to the wire rope; a vibration acceleration input unit that inputs vibration acceleration from an acceleration sensor that detects vibration acceleration and is installed on a load connected to an end of the wire rope; An inspection device characterized by comprising a judgment unit that detects a first timing at which the end of the wire rope moves and vibrates the load when tension begins to act on the wire rope based on the vibration acceleration input from the vibration acceleration input unit, and a second timing at which the load begins to move, and calculates the integrated value of the AE energy of the AE wave of the wire rope input from the AE wave input unit from the first timing until a predetermined time has elapsed after detecting the second timing, and judges whether the wire rope is in a broken state.

6. 6. The inspection device according to claim 5, wherein the determining unit displays the state of the broken wires of the wire rope by classifying the state into ranks of necessity for replacement.

7. The AE sensors are attached to two locations, top and bottom, at the bottom end of the hoist drum, The inspection device according to claim 5, wherein the determination unit removes AE waves generated on the hoist drum side when calculating the integrated value of AE energy of the AE waves of the wire rope.

8. 8. The inspection device according to claim 5, wherein the wire rope is a wire rope for a spillway gate installed in a dam.

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