Chain conveyor system, abnormality detection device, abnormality detection program, recording medium, and abnormality detection method

Abstract

To detect abnormality by fastening of a chain used for driving a conveyor.SOLUTION: A chain conveyor system (100) includes a pair of right and left chains (CH) used for driving a conveyor (80), and an abnormality detection device (1). The abnormality detection device (1) has an acquisition part (11) for acquiring a physical amount generated in a sprocket (SP), and a detection part (12) for detecting abnormality of the chain (CH) on the basis of an attention frequency component among frequency components obtained from time-series data of a physical amount. The attention frequency component is a frequency component corresponding to an installation position to the chain (CH) of an additional member provided on the chain (CH).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] One aspect of the present invention relates to a chain conveyor system and the like. [Background technology]

[0002] Patent document 1 discloses a method for diagnosing abnormalities in a sludge collector, which continuously scrapes up sludge that has settled in a sedimentation tank by moving flights (scraper plates) attached at predetermined intervals to an endless chain that is wound around a sprocket and rotates. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-153784 Summary of the Invention [Problem to be solved by the invention]

[0004] The invention described in Patent Document 1 relates to a method for diagnosing sprocket wear and / or endless chain elongation, and is not a method for determining abnormalities caused by chain sticking.

[0005] An object of one aspect of the present invention is to detect an abnormality caused by sticking of a chain used to drive a conveyor. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, a chain conveyor system according to one aspect of the present invention includes a chain used to drive a conveyor; an acquisition unit that acquires physical quantities generated in a sprocket as the sprocket rotates around the chain; and an abnormality detection device having a detection unit that detects an abnormality in the chain based on a frequency component of interest among frequency components obtained from time-series data of the physical quantities acquired by the acquisition unit, wherein the frequency component of interest is a frequency component that corresponds to the installation position of an accessory member attached to the chain relative to the chain.

[0007] In addition, an abnormality detection device according to one aspect of the present invention includes an acquisition unit that acquires physical quantities generated in a sprocket as the sprocket rotates, which rotates a chain used to drive a conveyor, and a detection unit that detects abnormalities in the chain based on a frequency component of interest among frequency components obtained from time series data of the physical quantities acquired by the acquisition unit, wherein the frequency component of interest is a frequency component that corresponds to the installation position of an associated member attached to the chain relative to the chain.

[0008] In addition, an abnormality detection method according to one aspect of the present invention includes an acquisition step of acquiring physical quantities generated in a sprocket as the sprocket rotates, which rotates a chain used to drive a conveyor, and a detection step of detecting an abnormality in the chain based on a frequency component of interest among frequency components obtained from time series data of the physical quantities acquired in the acquisition step, wherein the frequency component of interest is a frequency component corresponding to the installation position of an accessory member attached to the chain relative to the chain. [Effects of the Invention]

[0009] According to one aspect of the present invention, an abnormality due to sticking of a chain used to drive a conveyor can be detected. [Brief explanation of the drawings]

[0010] [Figure 1]1 is a side view schematically showing the configuration of a chain conveyor system according to a first embodiment of the present invention. [Figure 2] 2 is a plan view of the chain conveyor system shown in FIG. 1 as seen from the A1 direction shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] FIG. 2 is an enlarged side view schematically showing the periphery of a drive sprocket of the chain conveyor system shown in FIG. 1. [Figure 5] FIG. 1 is a block diagram showing an example of a configuration of a chain conveyor system. [Figure 6] 1 is a graph showing an example of time-series data of numerical values ​​that reflect physical quantities that occur in a sprocket as the drive sprocket rotates. [Figure 7] FIG. 10 is a diagram illustrating the relationship between the overlap rate and FFT target data. [Figure 8] 7 is a graph showing an example of a frequency spectrum derived by a detection unit using time-series data of motor current values ​​in the example shown in FIG. 6. [Figure 9] FIG. 10 is a diagram showing an example of an index indicating a tendency of a chain to stick, which is derived by a detection unit. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. However, the following description is intended to provide a better understanding of the gist of the invention and does not limit the present invention unless otherwise specified. For the sake of convenience, the drawings referred to in the following description show only the main components necessary for explaining the embodiment in a simplified form, and descriptions of well-known technical matters are omitted as appropriate for brevity. Therefore, the chain conveyor system of this embodiment may optionally include well-known components not shown in the drawings referred to. Furthermore, the shapes and dimensions of the components in the drawings do not necessarily reflect the actual shapes and dimensions, and have been changed as appropriate for clarity and simplification of the drawings.

[0012] In this embodiment, a chain conveyor system will be described which is used as an ash conveyor that is arranged in a plant having an incinerator (for example, a garbage incineration facility) and that conveys ash generated by the incinerator.

[0013] (Overall overview of the chain conveyor system) First, the overall configuration of a chain conveyor system 100 of the first embodiment will be described briefly with reference to Figs. 1 to 4. Fig. 1 is a side view schematically showing the configuration of the chain conveyor system 100. Fig. 2 is a plan view of the chain conveyor system 100 shown in Fig. 1 as viewed from the A1 direction. Fig. 2 shows an enlarged view of a portion related to the chain CH in the conveyor 80. Fig. 3 is a cross-sectional view taken along the line III-III in Fig. 2. Fig. 4 is an enlarged side view schematically showing the periphery of a drive sprocket SP1 of the chain conveyor system 100.

[0014] As shown in Figures 1 to 4, the chain conveyor system 100 includes a conveyor 80 and a conveyor driving device 81. The conveyor 80 moves an object to be conveyed in a predetermined conveying direction (direction D1 in Figure 1). In this embodiment, a case where the object to be conveyed is ash will be described as an example.

[0015] The conveyor 80 may include a pair of left and right chains CH (hereinafter simply referred to as "chains CH"), a pair of left and right drive sprockets (first sprockets) SP1, a pair of left and right driven sprockets (second sprockets) SP2, and a table TB. In Figure 1, only one drive sprocket SP1 and one driven sprocket SP2 are shown.

[0016] The chain CH may be an endless chain used to drive the conveyor 80. The chain CH may be provided with accompanying members. Examples of accompanying members include scrapers SK, flights, and conveying jigs. In this embodiment, the chain CH may be provided with a plurality of scrapers SK.

[0017] The scrapers SK are connected to the chain CH. As the chain CH rotates, the scrapers SK move along with the movement of the chain CH. In other words, the multiple scrapers SK move in the conveying direction at the same speed as the chain CH. Ashes, which are the target object, are conveyed by the movement of the scrapers SK. Specifically, the ash on the table TB can be conveyed by being pushed out by the scrapers SK. The scrapers SK have a pushing surface P1 that pushes out the ash. The scrapers SK are attached to the chain CH so that the pushing surface P1 faces the conveying direction D1 of the chain CH.

[0018] The chain CH has a first chain CH1 located on one side in the Y-axis direction of the XYZ axes shown in Figure 1 etc., and a second chain CH2 located on the other side. The following explanation of the first chain CH1 also applies to the second chain CH2. Therefore, a repeated explanation of the second chain CH2 will be omitted.

[0019] The first chain CH1 may have a plurality of link members LK (see Figures 2 and 3). The first chain CH1 may be formed by connecting a plurality of link members LK. A roller chain having a known structure can be used as the first chain CH1. Therefore, a detailed description of the structure of the first chain CH1 will be omitted, but the first chain CH1 may be formed, for example, by connecting outer links OLK and inner links ILK in an alternating combination. The outer links OLK have two plates (outer plates), and the inner links ILK have two plates (inner plates). The first chain CH1 may further include pins, rollers, bushings, etc.

[0020] In this embodiment, a retaining member 20 (e.g., an angle) may be attached to the plate of the two plates of the outer link OLK of the first chain CH1 that is located on the side of the second chain CH2, and a scraper SK may be attached to the retaining member 20. The scraper SK may be fixed to the retaining member 20 with fixing members such as bolts and nuts. Similarly, a scraper SK may be fixed to the outer link OLK of the second chain CH2. In this way, multiple scrapers SK may be provided for the chain CH so that the extrusion surface P1 of each of the multiple scrapers SK faces the conveying direction D1 of the chain CH.

[0021] The scrapers SK may be arranged in a predetermined pattern relative to the link members LK. As an example, the scrapers SK may be arranged at equal intervals along the conveying direction D1 relative to the chain CH. Note that the present invention is not limited to the above example, and the scrapers SK may be formed integrally with the plates of the outer links OLK or may be fixed to the plates of the inner links ILK.

[0022] The first chain CH1 has a ring shape and is wound around one drive sprocket SP1 and one driven sprocket SP2 located on one side in the Y-axis direction (positive side of the Y-axis) as shown in Figure 1 etc. The second chain CH2 has a ring shape and is wound around one drive sprocket SP1 and one driven sprocket SP2 located on the other side in the Y-axis direction (negative side of the Y-axis) as shown in Figure 1 etc.

[0023] The drive sprocket SP1 and the driven sprocket SP2 may each have an outer periphery configured to mesh with the chain CH. Known components can be used for the drive sprocket SP1 and the driven sprocket SP2. Therefore, detailed descriptions of the drive sprocket SP1 and the driven sprocket SP2 will be omitted.

[0024] The pair of drive sprockets SP1 are connected to a common drive shaft (not shown) and rotate with the rotation of the drive shaft. The drive shaft is rotated by power transmitted from the conveyor drive device 81.

[0025] As an example, the conveyor drive device 81 may include a motor MT and a power transmission mechanism PT. The power transmission mechanism PT may be, for example, a chain. When the motor MT rotates in a rotational direction R1, power is transmitted to the drive shaft via the power transmission mechanism PT, causing the drive sprocket SP1 to rotate in a rotational direction R2. As the drive sprocket SP1 rotates, the circular chain CH circulates between the drive sprocket SP1 and the driven sprocket SP2. The movement of the chain CH causes the driven sprocket SP2 to rotate in a rotational direction R3. In the example shown in FIG. 1 , the rotational directions R1, R2, and R3 are counterclockwise toward the positive Y-axis of the XYZ axes. Note that the power transmission mechanism PT may include gears, etc., and if the number of gear transmission stages is odd, the rotational directions R1 and R2 may be opposite to each other. If a worm reducer with orthogonal axes is used, the rotational axes may not be parallel to each other.

[0026] (Summary of the findings of the invention) Further referring to FIGS. 1 to 4, the findings of the present inventors regarding the chain conveyor system having the overall configuration described above will be outlined below.

[0027] In one example of the waste treatment flow in a waste incineration facility, ash is generated by an incinerator located upstream of the chain conveyor system 100 in the waste treatment flow. The ash sent from the incinerator to the ash extruder 90 is typically cooled with water inside the ash extruder 90. The ash extruder 90 then intermittently extrudes the ash from which a certain amount of moisture has been removed. For example, at least a portion of a table TB is located below a discharge port 91 in the ash extruder 90, and as ash AS1 is discharged from the discharge port 91, the ash AS1 accumulates on the table TB.

[0028] The scraper SK pushes out the ash on the table TB, and the ash pile AS2 is transported in the transport direction D1 as the scraper SK moves. Also, when the ash pile AS2 transported by the conveyor 80 is pushed out from the end of the table TB and falls vertically downward, the ash AS3 that falls from the table TB is sent downstream in the waste disposal flow through the ash chute CT.

[0029] Generally, the ash AS1 and the ash AS3 contain moisture. As the ash dries and solidifies over time, the chain CH may become stuck. This stuck chain CH may break.

[0030] A conventional technology for determining whether a conveyor has an abnormality (Patent Document 1) is known, which determines whether an abnormality exists by determining the increasing trend in the wave height of sideband wave components in the waveform obtained by frequency analysis of the conveyor's motor current. This technology detects chain elongation, which appears as a pitch error. Since sideband waves (sidebands) are generated by pitch error in the waveform obtained by frequency analysis, the presence or absence of an abnormality can be determined by determining the increasing trend in the wave height of the sideband wave components. However, because sticking in the ash conveyor described above is different from chain elongation, it cannot be detected using the same conventional approach.

[0031] As a result of extensive research, the inventors of the present invention have discovered the following: When frequency analysis is performed on time-series data of physical quantities generated in relation to the drive sprocket SP1 of the conveyor 80, a specific frequency component corresponding to the configuration of the conveyor 80 appears only when the chain CH is stuck. The physical quantity may be, for example, the current value of the motor MT that generates power to be transmitted to the drive sprocket SP1, or the torque value of rotation, vibrations around the sprocket SP1, etc. In this specification, the phrase "a certain frequency component appears" means that a peak corresponding to the frequency component appears in a graph showing the results of the frequency analysis.

[0032] More specifically, time-series data is obtained by measuring the physical quantities at a sampling period sufficiently small relative to the rotational speed. The time-series data is then subjected to frequency analysis. If no sticking occurs, only the frequency component corresponding to the chain pitch appears in the graph resulting from the frequency analysis. On the other hand, if sticking occurs, a peak of the frequency component corresponding to the scraper pitch appears in the graph resulting from the frequency analysis at the timing when the stuck portion of the chain CH passes the drive sprocket SP1. The presence or absence of an abnormality due to chain sticking can be determined by, for example, performing threshold determination using the peak intensity of the frequency component corresponding to the scraper pitch. The relationship between chain sticking and scraper pitch will be described in more detail below with specific examples.

[0033] (System Configuration) 5 is a block diagram showing an example of the configuration of a chain conveyor system 100. As shown in FIG. 5, the chain conveyor system 100 in this embodiment includes an abnormality detection device 1 in addition to a conveyor 80 and a conveyor driving device 81.

[0034] The conveyor driving device 81 has a control device 70. The control device 70 may be provided outside the conveyor driving device 81, and may be included in a computer (e.g., a control system) that is higher in rank than the conveyor driving device 81, for example.

[0035] The motor MT is driven based on an electrical signal from the control device 70. The rotation of the motor MT is transmitted to the drive sprocket SP1 via the power transmission mechanism PT. The rotation of the drive sprocket SP1 can move the chain CH.

[0036] The abnormality detection device 1 detects an abnormality in the chain CH. The abnormality detection device 1 includes an acquisition unit 11 and a detection unit 12. The abnormality detection device 1 may further include an identification unit 13.

[0037] The acquisition unit 11 acquires physical quantities that occur in the drive sprocket SP1 as the drive sprocket SP1 rotates. Therefore, the acquisition unit 11 acquires time-series data of the physical quantities. In this embodiment, an example will be described in which the motor current value is acquired as the physical quantity. The acquisition unit 11 may acquire the time-series data from, for example, the control device 70, or from a sensor (not shown) attached to the cable of the motor MT. Alternatively, the time-series data may be acquired using, for example, a data logger.

[0038] The detection unit 12 acquires the time series data from the acquisition unit 11. The detection unit 12 may derive frequency components of the physical quantity (motor current value) from the time series data. The detection unit 12 can detect an abnormality in the chain CH based on a frequency component of interest (hereinafter referred to as a frequency component of interest) among the frequency components.

[0039] In the example of the first embodiment, the frequency component of interest is a frequency component corresponding to the installation position of the scraper SK relative to the chain CH. As an example, the detection unit 12 may predict when the numerical value of the intensity of the frequency component of interest will reach a predetermined threshold value based on the change in the intensity of the frequency component of interest over time. In this case, the control device 70 may function as a detector DT, and the detection unit 12 may acquire time-series data of the above numerical value from the control device 70 via the acquisition unit 11. The detection unit 12 may then detect an abnormality in the chain CH based on the time-series data of the above numerical value. Therefore, for example, the detection unit 12 may detect an abnormality in the chain CH based on the presence or intensity of a frequency component corresponding to the installation position of the scraper SK. The processing performed by the detection unit 12 is described below.

[0040] Fig. 6 is a graph showing an example of time-series data of numerical values ​​reflecting physical quantities occurring in the drive sprocket SP1 as the drive sprocket SP1 rotates. Fig. 6 shows an example in which the numerical values ​​reflecting the physical quantities are used as motor current values, and the vertical axis of Fig. 6 represents the motor current values.

[0041] The detector 12 may acquire time-series data of the motor current value from the control device 70 via the acquirer 11. The example in Fig. 6 shows the result of detecting the current over 24 hours (hours) at a predetermined sampling period Ts (unit: s).

[0042] In the example in Figure 6, Total length of chain CH: 60m Conveyor line speed (conveyor 80 conveyor speed): 0.85 m / min Scraper pitch (the distance between each of the multiple scrapers SK): 1m Chain pitch: 0.25m The chain pitch corresponds to the distance from one roller to the next in the chain CH. Below, we will explain an example in which the scraper pitch is uniform throughout the chain CH (scrapers SK are evenly spaced).

[0043] The conveyor line speed can be interpreted as the movement speed of the chain CH (or the movement speed of the scraper SK).

[0044] The detector 12 may perform frequency analysis on the time series data of the motor current value. For example, the detector 12 may perform FFT (Fast Fourier Transform) processing on the time series data of the motor current value.

[0045] The sampling period Ts is Ts≦CH_PITCT / (V_CONV×2)…(1) where CH_PITCT is the chain pitch (unit: m), and V_CONV is the conveyor line speed (unit: m / s). The coefficient 2 on the right side of equation (1) is set with the intention of obtaining spectral information in the frequency band up to half the sampling frequency by FFT.

[0046] In the example of FIG. 6, CH_PITCT=0.25 m, V_CONV=0.85 m / min≒0.0142 m / s. Therefore, Ts may be set to ≦8.80 s. This facilitates appropriate FFT processing. In the example of FIG. 6, Ts is set to 1 s. Therefore, the acquisition unit 11 may sample the current value every second.

[0047] Next, the detection unit 12 may extract a partial section of the time series data using a time window 400 having a predetermined length Tw (unit: seconds). Tw is also referred to as the time window length. Examples of window functions used in FFT processing include a Hanning window, a rectangular window, and a flat-top window. The window function used in the example of embodiment 1 is a Hanning window.

[0048] For FFT processing, it is desirable that the number of data (number of sampling points) n is set to a value equal to a power of 2. Therefore, under the condition that Ts=1s, Tw is Tw=2 n It is expressed as:

[0049] The minimum value Tw(min) of the time window length under the condition of Ts=1 s is, for example, Tw(min)=2 n1 ≧(SK_PITCT×2) / V_CONV …(2) n1 is the number of data points corresponding to Tw(min). SK_PITCT is the scraper pitch.

[0050] As an example, the maximum value Tw(max) of the time window length under the condition of Ts=1 s may be set so as not to exceed five times the value of the rightmost side of equation (2). In this case, Tw(max) is Tw(max)=2 n2 ≦(SK_PITCT×10) / V_CONV …(3) n2 is the number of data corresponding to Tw(max). Naturally, n2 is any natural number greater than n1.

[0051] In the example of Figure 6, n may be set to a value greater than or equal to n1 and less than or equal to n2. By setting n in this manner, Tw can be set to a value greater than or equal to Tw(min) and less than or equal to Tw(max). In the example of Figure 6, SK_PITCH = 1 m, so the value of the rightmost side of equation (2) is approximately 140 s. Therefore, the value of the rightmost side of equation (3) is approximately 700 s.

[0052] Therefore, in the example of Fig. 6, if n1 = 8 and n2 = 9 are set, the above-mentioned formulas (2) and (3) are satisfied. Therefore, in the example of Fig. 6, n = 9 is set by the user. Therefore, in the example of Fig. 6, the detection unit 12 sets Tw as Tw = 512 s in accordance with the set value of n = 9.

[0053] The detection unit 12 may generate FFT target data from a part of the time series data extracted using the time window 400 (hereinafter referred to as extracted time series data) in accordance with a predetermined overlap rate. In the first embodiment, a case where the overlap rate is set to 50% is exemplified.

[0054] 7 is a diagram illustrating the relationship between the overlap rate and FFT target data. Reference numerals 501, 502, and 503 in FIG. 7 respectively represent examples of the first, second, and third slots (time slots) in FFT target data generated at an overlap rate of 50%. In the following description, the length of one slot of FFT target data is represented as TF. In FIG. 7, the start time (initial time) is set to 0, and TF is the same value as the time window length Tw of the time window 400 (512 s ≈ 8.5 min).

[0055] First, as indicated by the reference numeral 501, the detection unit 12 acquires post-extraction time-series data in the period from the start time point to TF as the first slot of the FFT target data. The end time point of one slot in the FFT target data is TF after the start time point.

[0056] Hereinafter, the average point between the start and end points of one slot will be referred to as the center point. The portion of one slot from the start to the center point will be referred to as the first half. On the other hand, the portion of one slot from the center to the end will be referred to as the second half.

[0057] Next, the detection unit 12 copies (duplicates) the latter half of the first slot. Then, as indicated by reference numeral 502, the detection unit 12 assigns the copied latter half of the first slot as the first half of the second slot. Therefore, the second slot overlaps with the first slot over half the slot length (a period that is 50% of the slot length). Next, the detection unit 12 acquires the extracted time-series data for the period from time TF to TF×3 / 2 as the latter half of the second slot.

[0058] Next, the detection unit 12 copies the latter half of the second slot. Then, as indicated by reference numeral 503, the detection unit 12 assigns the copied latter half of the second slot as the first half of the third slot. Therefore, the third slot overlaps with the second slot over half a slot length. Next, the detection unit 12 acquires the post-extraction time series data for the period from time TF×3 / 2 to TF×2 as the latter half of the third slot. As described above, when the overlap rate is 50%, data of the post-extraction time series data is acquired progressively every half slot length.

[0059] The detection unit 12 may derive the frequency spectrum of the motor current value by performing an FFT using a window function (e.g., a Hanning window) on the FFT target data generated as described above. Fig. 8 is a graph showing an example of the frequency spectrum derived by the detection unit 12 using the time-series data of the motor current value shown in Fig. 6.

[0060] The horizontal and vertical axes in the graph of FIG. 8 represent the converted frequency and intensity, respectively, in the frequency spectrum. The intensity in the graph of FIG. 8 may be used as an index representing the amplitude of the current waveform. The converted frequency in the graph of FIG. 8 is a value obtained by converting the number of fluctuations per unit time (frequency) into the number of fluctuations per scraper pitch. Specifically, the number of fluctuations per unit length is obtained by dividing the data after FFT (horizontal axis unit: 1 / min) by the line speed (m / min), and the result is further divided by the scraper pitch (1 / m) to obtain the number of fluctuations per scraper pitch. In the example of FIG. 8, a converted frequency of 1 corresponds to the scraper pitch (1 m).

[0061] In the example shown in Figure 6, the line speed is 0.85 m / min, so seven or eight scrapers SK are located within the time window length Tw of 512 s. When a Hanning window is used as the window function, a weighting function (window function) is used in which the data approaches zero as it approaches both ends of each slot. Therefore, information about the scrapers SK at both ends of the slot is not reflected in the FFT results. Therefore, the characteristics of the scraper SK located at the center point are effectively reflected in the FFT results for each slot.

[0062] The above explanation can be summarized as follows. That is, the time window length Tw can be set so that a portion of the chain CH with a length equivalent to the time window length Tw includes multiple scrapers SK (for example, three or more, typically about five to seven). In the above example, the line speed is 0.85 m / min, and the length of the chain CH equivalent to the time window length Tw of 512 s (about 8.5 min) is 7.25 m, so 7.25 scrapers SK will be included in the period of the time window length Tw.

[0063] The graph resulting from the FFT analysis using a window function such as a Hanning window or a flat-top window (a Hanning window in the above example) effectively reflects the characteristics of the scraper SK that corresponds to near the center point in the slot with the time window length Tw, i.e., the 3.6th scraper SK (rounded to the nearest 4th) out of 7.25 scrapers SK.

[0064] Then, for example, the overlap rate is set to 50% and each slot of the time series data is analyzed for each time window length Tw. As a result, if the time series data to be analyzed starts from the first scraper SK, for example, every 3.6 scrapers SK (rounded up or down, for example, the 4th, 7th, 11th, 14th, etc.) can be analyzed based on the frequency analysis results. The scrapers SK that were not analyzed during the first rotation of the rotating chain CH (for example, the 1st to 3rd, 5th, 6th, etc.) are located at the center of the slots from the second rotation of the chain CH onwards, and can therefore be analyzed from the second rotation of the chain CH onwards.

[0065] From the above, in the chain conveyor system 100, the total number X of scrapers SK installed on the chain CH (60 in the above example) may be set so that it is not an integer multiple of the interval Y of the number of scrapers SK to be analyzed (3.6 in the above example) (the total number X is not divisible by the interval Y). By analyzing a certain period of time in the time-series data (three revolutions of the chain CH in the above example), all scrapers SK can be analyzed. In the chain conveyor system 100, the total number X and the interval Y of the number may have a least common multiple (180 in the above example).

[0066] The overlap rate is not necessarily limited to 50% and may be set as appropriate. The larger the overlap rate, the shorter the interval between determining whether or not each part of the circular chain CH is stuck, but the amount of calculation (load) per unit time of the detection unit 12 increases. The smaller the overlap rate, the longer the interval between determining whether or not each part of the circular chain CH is stuck, and the longer the time required to analyze all scrapers SK.

[0067] As shown in the graph labeled 810 in Figure 8, when the chain CH is not stuck, a prominent peak (referred to as the main peak) appears at a converted frequency of 4.00. This peak corresponds to the chain pitch, and therefore appears regardless of whether the chain CH is stuck or not.

[0068] On the other hand, as shown in the graph indicated by reference numeral 820 in Fig. 8, when the chain CH is stuck, in addition to the main peak, a first peak (a peak at a position where the converted frequency is 1) appears in the frequency spectrum. A second peak (a peak at a position where the converted frequency is 2) in the frequency spectrum tends to appear along with the appearance of the first peak.

[0069] In the chain conveyor system 100 of this embodiment, the first peak can be the frequency component of interest. Alternatively, the first peak and the second peak can be the frequency components of interest. In other words, the frequency component of interest may be a frequency component corresponding to the installation position of the scraper SK (ancillary member) with respect to the chain CH.

[0070] The detection unit 12 may detect an abnormality in the chain CH based on the presence or absence or intensity of a frequency component of interest. The presence or absence of a frequency component of interest means whether a peak of the frequency component of interest exists in the frequency spectrum. The presence or absence of a peak may be determined based on whether the peak can be distinguished from baseline noise in the frequency spectrum, or whether the peak intensity exceeds a predetermined threshold.

[0071] For example, if there is no peak of the frequency component of interest, the detection unit 12 may determine that the chain CH is in a normal state (no abnormality has occurred in the chain CH), and if there is a peak of the frequency component of interest, the detection unit 12 may determine that there is an abnormality in the chain CH.

[0072] As another example, the detection unit 12 may determine that the chain CH is in a normal state when the frequency component of interest is below a predetermined threshold value, and may determine that an abnormality has occurred in the chain CH when the frequency component of interest is equal to or greater than the threshold value.

[0073] The detection unit 12 may derive an index indicating the tendency of the chain CH to stick for each of the multiple scrapers SK by performing frequency analysis. FIG. 9 shows an example of the index derived by the detection unit 12. For example, a reference position may be predetermined for the chain CH. In the example of FIG. 9, the chain CH has a total length of 60 m and 60 scrapers SK are arranged with a scraper pitch of 1 m. In the example of FIG. 9, scraper numbers 1 to 60 are assigned to each of the 60 scrapers SK based on the reference position of the chain CH. The reference position of the chain CH can be set by the user as appropriate, and the specific method for setting the reference position of the chain CH is not particularly limited.

[0074] In the example of FIG. 9, the detection unit 12 performs FFT processing on the entire time-series data over 24 hours with a time window length Tw of 512 seconds and an overlap rate of 50%, as described above. The detection unit 12 then derives the intensity (first intensity) at converted frequency 1 for each of scraper numbers 1 to 60. Because the peak at converted frequency 2 (the second peak described above) tends to appear when the peak at converted frequency 1 (the first peak described above) appears, the intensity (second intensity) at converted frequency 2 does not need to be considered. The first intensity and the second intensity are examples of indicators indicating the tendency of the chain CH to stick. The first intensity may be the peak intensity at the first peak described above, and the second intensity may be the peak intensity at the second peak described above. The graph of FIG. 9 shows all data calculated for the entire time-series data over 24 hours, so multiple first intensities are plotted for each scraper number.

[0075] In the example of Fig. 9, most of the data points are concentrated at positions near index 0. A small index for a certain data point (e.g., close to 0) means that the intensity of the frequency component of interest is small in the part of the chain CH corresponding to that data point, suggesting that that part of the chain CH is in a normal state.

[0076] On the other hand, a large index for a certain data point means that the intensity of the frequency component of interest is high in the part of the chain CH corresponding to that data point, suggesting that an abnormality has occurred in that part of the chain CH.

[0077] Therefore, the identification unit 13 may identify the stuck position of the chain CH based on the index of the data point. For example, if the index of a certain data point is equal to or greater than a predetermined threshold, the identification unit 13 may determine that the chain CH is stuck at the position corresponding to the data point. As described above, the data points shown in FIG. 9 correspond to scraper numbers. In the example of FIG. 9, the predetermined threshold is set to 0.10.

[0078] As an example, point P_ab2 in FIG. 9 (the point with the highest index among the multiple points corresponding to scraper number 2) has an index higher than 0.10. Therefore, the identifying unit 13 identifies point P_ab2 as an abnormal point. Then, the identifying unit 13 may identify that sticking has occurred at the position of scraper number 2 on the chain CH at the time point when point P_ab2 is detected.

[0079] As another example, point P_ab42 in FIG. 9 (the point with the highest index among the multiple points corresponding to scraper number 42) also has an index higher than 0.10. Therefore, the identifying unit 13 identifies point P_ab42 as an abnormal point. Then, the identifying unit 13 may determine that sticking has occurred at the position of scraper number 42 on the chain CH at the time point when point P_ab42 is detected.

[0080] As described above, the identifying unit 13 may identify the fixing position of the chain CH based on (i) the occurrence timing of the target frequency component that exceeds a predetermined threshold, and (ii) the reference position.

[0081] Here, among the multiple link members LK connected to each other in the chain CH, the link members LK (see FIG. 2) on which the multiple scrapers SK are respectively installed are referred to as first link members LK1. The multiple first link members LK1 may correspond one-to-one to the multiple scrapers SK. The link members LK located immediately before each of the multiple first link members LK1 in the movement direction of the chain CH (conveying direction D1) are referred to as second link members LK2. The term "located immediately before" above means the following: For example, if a virtual plane (virtual plane) perpendicular to the conveying direction D1 is set at an arbitrary position, the second link member LK2 will pass through the virtual plane just before the first link member LK1 passes through the virtual plane as the chain CH moves in the conveying direction D1.

[0082] Specific examples of the first link member LK1 and the second link member LK2 will be described with reference to Figures 2 and 3 again. In the example shown in Figures 2 and 3, the first link member LK1 is an outer link OLK on which a scraper SK is installed. The second link member LK2 is an inner link ILK that is connected to the outer link OLK on which the scraper SK is installed and is located downstream in the conveying direction D1 (on the left side of the paper in Figures 2 and 3).

[0083] According to the findings of the inventors, the chain CH tends to stick at the connection between the first link member LK1 and the second link member LK2. As described above, the extrusion surface P1 of the scraper SK faces the conveying direction D1 and moves in the conveying direction D1 together with the chain CH. As the ash is conveyed in the conveying direction D1 by the scraper SK, ash that exceeds the height of the scraper SK spills over and is conveyed by the scraper SK on the upstream side (the right side of the paper in Figures 2 and 3). Ash that has traveled over the scraper SK attached to the first link member LK1 often falls on the connection between the first link member LK1 and the immediately preceding second link member LK2. For example, with the shape and installation of the scraper SK shown in Figure 2, ash that has traveled over the scraper SK attached to the first link member LK1 often falls on the connection between the first link member LK1 and the immediately preceding second link member LK2. 2 and 3, the connecting portions are located near both ends of the extrusion surface P1 of the scraper SK in the width direction. The width direction of the extrusion surface P1 is a direction perpendicular to both the height direction of the extrusion surface P1 from the table TB and the conveying direction D1. Typically, the width direction of the extrusion surface P1 may be the longitudinal direction.

[0084] Therefore, the identification unit 13 may identify a first link member LK1 among the multiple first link members LK1 in which an abnormality has occurred at the connection portion with the second link member LK2, by distinguishing the multiple first link members LK1, for example, by the scraper number of the scraper SK, as described above, based on the intensity of the frequency components corresponding to the multiple first link members LK1.

[0085] The identifying unit 13 may also identify the first link member LK1 in which an abnormality has occurred as follows: That is, the link members LK located immediately after each of the plurality of first link members LK1 in the movement direction of the chain CH (conveying direction D1) are referred to as third link members LK3. The third link member LK3 is an inner link ILK that is connected to an outer link OLK on which a scraper SK is installed and is located on the upstream side in the conveying direction D1 (the right side of the paper in FIGS. 2 and 3). Depending on the shape and installation mode of the scraper SK, ash that has traveled over the scraper SK installed on the first link member LK1 often covers the connection portion between the first link member LK1 and the third link member LK3 immediately thereafter. The identification unit 13 may identify a first link member LK1 among the multiple first link members LK1 in which an abnormality has occurred at the connection portion with the third link member LK3, by distinguishing the multiple first link members LK1, for example, by the scraper number of the scraper SK, as described above, based on the intensity of the frequency components corresponding to the multiple first link members LK1.

[0086] (Advantages of chain conveyor systems) As described above, the chain conveyor system 100 of this embodiment can detect the sticking of the chain CH. Therefore, the possibility of the chain CH breaking due to sticking can be reduced. As a result, it is possible to prevent the conveyor 80 from having to stop driving. Furthermore, by identifying the location of the sticking, it is possible to shorten the maintenance time. By identifying the location where sticking may occur, it is also possible to take maintenance measures before the chain CH sticks.

[0087] (Anomaly detection method) The scope of the present invention also includes an abnormality detection method corresponding to the abnormality detection process performed in the chain conveyor system 100 described above. This can be summarized as follows, for example.

[0088] An abnormality detection method according to one embodiment of the present invention includes an acquisition step of acquiring physical quantities generated in a sprocket (e.g., a drive sprocket SP1) that rotates a pair of left and right chains CH used to drive a conveyor 80, and a detection step of detecting an abnormality in the chain CH based on a frequency component of interest among frequency components obtained from time-series data of the physical quantities acquired in the acquisition step. The frequency component of interest is a frequency component corresponding to the installation position of an accessory member (e.g., a scraper SK) provided to the chain CH relative to the chain CH.

[0089] In the detection process, an abnormality in the chain CH is detected, and the position of the part of the chain CH where the abnormality has occurred (for example, the first link member LK1) may be identified based on, for example, the scraper number of the scraper SK as described above.

[0090] (Other configuration examples) (a) The conveyed object is not limited to ash. In a usage mode in which the chain CH may become stuck, the chain conveyor system 100 can effectively detect the stuck chain CH.

[0091] (b) The conveyor driving device 81 is not particularly limited in its specific configuration as long as it can drive the conveyor 80. It is sufficient that information on physical quantities occurring in the driving sprocket SP1 as the driving sprocket SP1 rotates can be obtained (for details, see the second embodiment described below).

[0092] [Embodiment 2] A chain conveyor system 100 according to another embodiment will be described below. For convenience of explanation, members having the same components as those described in the first embodiment will be denoted by the same reference numerals in the following embodiments, and their description will not be repeated.

[0093] The chain conveyor system 100 may further include a detector DT. The detector DT may detect a value that reflects a change in the force required to rotate the sprocket SP, and may acquire data indicating a change in the value over time (time-series data of the value). The acquisition unit 11 may acquire the time-series data of the value from the detector DT.

[0094] For example, the force required to rotate the sprocket SP may be the torque (motor torque) supplied from the motor MT to the sprocket SP. Generally, motor torque varies depending on the current supplied to the motor MT. For this reason, the motor torque may be detected based on the current value. The detector DT may be a current sensor that detects current. For example, if the motor MT is an inverter motor, the acquisition unit 11 may acquire the current value from a control panel. If the motor MT is a general-purpose motor, the secondary current may also be detected using a clamp-on ammeter. In the case of an equivalent circuit of a three-phase induction motor, the current value may be measured by providing a clamp-on ammeter on the secondary side.

[0095] Furthermore, if the motor torque increases, the vibration (hereinafter simply referred to as vibration) generated in the motor MT or related components may increase. Therefore, vibration is another example of a numerical value that reflects a change in the force required to rotate the sprocket SP. For this reason, the detector DT may be a vibration sensor that detects vibration.

[0096] For example, the motor MT may have a bearing at the connection between the motor MT and the sprocket SP to support the load of the sprocket SP. In this case, it is expected that the vibration generated in the bearing has a high correlation to the motor torque. Therefore, the vibration sensor may be attached to the bearing.

[0097] However, the location where the vibration sensor is attached is not limited to the above example. As another example, the vibration sensor may be attached to the frame of the motor MT. In this case, the vibration sensor installation work is easier than when the vibration sensor is attached to a bearing.

[0098] As yet another example, when motor torque is used as a numerical value that reflects a change in the force required to rotate the sprocket SP, the detector DT may be a torque meter that detects motor torque.

[0099] As described above, frequency components can be obtained from time-series data measuring values ​​indicating the force required to rotate the sprocket SP (e.g., motor torque values) or vibrations associated with the motor MT (e.g., vibrations around the sprocket SP). Chain abnormalities can then be detected based on a frequency component of interest among the frequency components.

[0100] [Software implementation example] The functions of the chain conveyor system 100 (hereinafter referred to as the "device" for convenience) can be realized by a program (an abnormality detection program) that causes a computer to function as the device, and that causes a computer to function as each control block of the device (in particular, each part included in the abnormality detection device 1).

[0101] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The control device and storage device execute the program, thereby realizing the functions described in each of the above embodiments.

[0102] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0103] In addition, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of one aspect of the present invention. In addition, the functions of the control blocks can be realized by, for example, a quantum computer.

[0104] Furthermore, each process described in each of the above embodiments may be executed by AI (Artificial Intelligence). In this case, the AI ​​may run on the control device or on another device (for example, an edge computer or a cloud server).

[0105] 〔summary〕 A chain conveyor system according to a first aspect of the present invention comprises a pair of left and right chains used to drive a conveyor; an acquisition unit that acquires physical quantities generated in a sprocket as the sprocket rotates around the chain; and an abnormality detection device having a detection unit that detects an abnormality in the chain based on a frequency component of interest among frequency components obtained from time-series data of the physical quantities acquired by the acquisition unit, wherein the frequency component of interest is a frequency component that corresponds to the installation position of an accessory member attached to the chain with respect to the chain.

[0106] In a chain conveyor system according to a second aspect of the present invention, as in the first aspect, the acquisition unit acquires data showing changes over time in a numerical value that reflects changes in the force required to rotate the sprocket, and the detection unit may detect an abnormality in the chain based on the presence or absence or strength of a frequency component corresponding to the installation position of the auxiliary member.

[0107] In a chain conveyor system according to a third aspect of the present invention, in the first or second aspect, the chain may be formed by connecting a plurality of link members, and a plurality of scrapers may be installed as the auxiliary members in a predetermined pattern relative to the plurality of link members.

[0108] A fourth aspect of the present invention relates to a chain conveyor system according to the third aspect, wherein a reference position is predetermined for the chain, and the abnormality detection device may further include an identification unit that identifies a stuck position of the chain based on the reference position and the occurrence timing of the frequency component of interest that exceeds a predetermined threshold.

[0109] In a chain conveyor system according to a fifth aspect of the present invention, in the fourth aspect, the chain has a plurality of first link members on which a plurality of the scrapers are respectively installed, and a plurality of second link members located immediately before each of the plurality of first link members in the movement direction of the chain, and the identification unit may identify, among the plurality of first link members, a first link member in which an abnormality has occurred at the connection portion with the second link member based on the intensity of a frequency component corresponding to the first link member.

[0110] In a chain conveyor system according to a sixth aspect of the present invention, in any one of the first to fifth aspects, the detection unit may predict, based on a change in the intensity of the frequency component of interest over time, when the intensity of the frequency component of interest will reach a predetermined threshold value.

[0111] A chain conveyor system according to a seventh aspect of the present invention is in any one of the first to sixth aspects and may further include a detector that detects a numerical value that reflects a change in the force required to rotate the sprocket.

[0112] An abnormality detection device according to aspect 8 of the present invention comprises an acquisition unit that acquires physical quantities generated in a sprocket as the sprocket rotates, which rotates a pair of left and right chains used to drive a conveyor, and a detection unit that detects abnormalities in the chain based on a frequency component of interest among frequency components obtained from time series data of the physical quantities acquired by the acquisition unit, wherein the frequency component of interest is a frequency component corresponding to the installation position of an accessory member attached to the chain relative to the chain.

[0113] An abnormality detection program according to a ninth aspect of the present invention is an abnormality detection program for causing a computer to function as the abnormality detection device according to the eighth aspect, and may cause the computer to function as the acquisition unit and the detection unit.

[0114] A computer-readable recording medium according to a tenth aspect of the present invention may store the anomaly detection program according to the ninth aspect.

[0115] An abnormality detection method according to aspect 11 of the present invention includes an acquisition step of acquiring physical quantities generated in a sprocket when the sprocket that rotates a pair of left and right chains used to drive a conveyor is rotated, and a detection step of detecting an abnormality in the chain based on a frequency component of interest among frequency components obtained from time series data of the physical quantities acquired in the acquisition step, wherein the frequency component of interest is a frequency component corresponding to the installation position of a component of the chain.

[0116] [Additional Notes] One aspect of the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of one aspect of the present invention. [Explanation of symbols]

[0117] 1. Anomaly detection device 11 Acquisition Department 12 Detector 13 Specific section 80 Conveyor 81 Conveyor drive unit 100 Chain Conveyor System CH Chain SP sprocket SK scraper (accessory part) LK link member LK1 First link member LK2 Second link member

Claims

1. A pair of left and right chains used to drive a conveyor that transports objects to be transported; an abnormality detection device including an acquisition unit that acquires physical quantities generated in the sprocket as the sprocket that rotates the chain rotates, and a detection unit that detects abnormalities in the chain based on a frequency component of interest among frequency components obtained from time series data of the physical quantities acquired by the acquisition unit; a plurality of auxiliary members that are installed on the chain at predetermined intervals in the extending direction of the chain and that are involved in the transport of the transport object that is performed in conjunction with the movement of the chain; The frequency component of interest is a frequency component in a frequency spectrum obtained for each of the associated components, and is a frequency component that appears in response to an abnormality in the chain.

2. the acquisition unit acquires data indicating a change over time in a numerical value that reflects a change in the force required to rotate the sprocket; The chain conveyor system according to claim 1 , wherein the detection unit detects an abnormality in the chain based on the presence or absence or intensity of the frequency component of interest.

3. 3. The chain conveyor system according to claim 1, wherein the chain is formed by connecting a plurality of link members, and a plurality of scrapers are provided as the auxiliary members on the plurality of link members in a predetermined pattern.

4. A reference position is predetermined on the chain, 4. The chain conveyor system according to claim 3, wherein the abnormality detection device further comprises an identification unit that identifies a stuck position of the chain based on the reference position and the occurrence timing of the frequency component of interest that exceeds a predetermined threshold.

5. the chain includes a plurality of first link members on which the plurality of scrapers are respectively installed, and a plurality of second link members positioned immediately before each of the plurality of first link members in the movement direction of the chain, 5. The chain conveyor system according to claim 4, wherein the identification unit identifies, among the plurality of first link members, the first link member in which an abnormality has occurred at a connection portion with the second link member, based on an intensity of the frequency component of interest in the frequency spectrum obtained for the scraper installed on the first link member.

6. 2. The chain conveyor system according to claim 1, wherein the detection unit predicts, based on a change over time in the intensity of the frequency component of interest, when the intensity of the frequency component of interest will reach a predetermined threshold value.

7. 10. The chain conveyor system of claim 1, further comprising a detector that detects a numerical value reflecting a change in the force required to rotate the sprocket.

8. An acquisition unit that acquires physical quantities generated in a sprocket as the sprocket rotates to rotate a pair of left and right chains used to drive a conveyor that transports an object to be transported; a detection unit that detects an abnormality in the chain based on a frequency component of interest among frequency components obtained from the time-series data of the physical quantity acquired by the acquisition unit, The chain has a plurality of auxiliary members that are involved in the transport of the object to be transported as the chain moves, the auxiliary members being installed at predetermined intervals in the extending direction of the chain, An abnormality detection device, wherein the frequency component of interest is a frequency component in a frequency spectrum obtained for each of the auxiliary components, and is a frequency component that appears in response to the occurrence of an abnormality in the chain.

9. 9. An abnormality detection program for causing a computer to function as the abnormality detection device according to claim 8, wherein the abnormality detection program causes a computer to function as the acquisition unit and the detection unit.

10. A computer-readable recording medium on which the abnormality detection program according to claim 9 is recorded.

11. An acquisition process for acquiring physical quantities generated in a sprocket as the sprocket rotates to rotate a pair of left and right chains used to drive a conveyor that transports an object to be transported; a detection step of detecting an abnormality in the chain based on a frequency component of interest among frequency components obtained from the time-series data of the physical quantity obtained in the acquisition step, The chain has a plurality of auxiliary members that are involved in the transport of the object to be transported as the chain moves, the auxiliary members being installed at predetermined intervals in the extending direction of the chain, An abnormality detection method in which the frequency component of interest is a frequency component in a frequency spectrum obtained for each of the auxiliary components, and is a frequency component that appears in conjunction with the occurrence of an abnormality in the chain.

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