Diagnostic system, diagnostic method, and diagnostic program

Abstract

To specify the abrasion loss of a centrifugal dehydrator.SOLUTION: A diagnosis system for diagnosing a centrifugal dehydrator including an outer body and an inner body that are coaxially disposed, are pivotally supported at two bearing portions provided at both ends in an extending direction, and rotate at different rotation speeds, the inner body having a screw spirally provided on an outer periphery thereof, the diagnosis system including measurement devices 2, 3, and 4 that measure a physical quantity related to the centrifugal dehydrator, and an arithmetic device 5, in which the arithmetic device 5 is capable of realizing a wear amount specifying function of specifying a wear amount of a tip portion of the screw based on the physical quantity.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a diagnostic system, a diagnostic method, and a diagnostic program for diagnosing a centrifugal dehydrator. [Background technology]

[0002] A commonly used method for diagnosing equipment having a rotary drive unit is to focus on vibrations that occur during operation of the equipment and perform diagnosis based on electrically measured vibration waveforms. For example, Japanese Patent Laid-Open Publication No. 8-122305 (Patent Document 1) discloses a bearing abnormality diagnosis device that measures acoustic emissions (AE) generated by bearings with an AE sensor and diagnoses bearing abnormalities based on the AE signal output by this AE sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-122305 Summary of the Invention [Problem to be solved by the invention]

[0004] In devices with rotary drive units, wear occurs in the components as the device continues to be used. Wear of components is a typical cause of malfunctions in this type of device. If the amount of wear could be determined without dismantling the device, it would be easier to carry out planned maintenance. However, the invention described in Patent Document 1 was unable to determine the amount of wear in the device.

[0005] Therefore, it is desirable to realize a diagnostic system, a diagnostic method, and a diagnostic program that can identify the amount of wear in a centrifugal dehydrator. [Means for solving the problem]

[0006] The diagnostic system of the present invention is a diagnostic system for diagnosing a centrifugal dehydrator that has an outer barrel and an inner barrel that are concentrically arranged, supported by two bearing portions provided at both ends in the extension direction, and that rotate at different rotational speeds, and the inner barrel has a screw that is spirally provided on its outer periphery, and is characterized in that it comprises a measuring device that measures physical quantities related to the centrifugal dehydrator, and a computing device, and the computing device is capable of realizing a wear amount identification function that identifies the wear amount of the tip of the screw based on the physical quantities.

[0007] The diagnostic method of the present invention is a method for diagnosing a centrifugal dehydrator having an outer barrel and an inner barrel that are concentrically arranged, supported by two bearing portions provided at both ends in the extension direction, and that rotate at different rotational speeds, the inner barrel having a screw spirally provided on its outer periphery, and is characterized by including a measurement step of measuring physical quantities related to the centrifugal dehydrator, and a wear amount determination step of determining the amount of wear at the tip of the screw based on the physical quantities.

[0008] The diagnostic program of the present invention is a diagnostic program for diagnosing a centrifugal dehydrator having an outer barrel and an inner barrel that are concentrically arranged, supported by two bearing portions provided at both ends in the extension direction, and that rotate at different rotational speeds, and the inner barrel has a screw that is spirally provided on its outer periphery, and is characterized in that when executed by a computer, it is capable of realizing a physical quantity acquisition function that acquires physical quantities related to the centrifugal dehydrator, and a wear amount identification function that identifies the wear amount of the tip of the screw based on the physical quantities.

[0009] These configurations allow the wear amount of the centrifugal dehydrator to be identified, making it easier to carry out planned maintenance.

[0010] Preferred embodiments of the present invention will be described below, but the scope of the present invention is not limited to the preferred embodiments described below.

[0011] In the diagnostic system of the present invention, the computing device can further realize a residual imbalance identification function that identifies residual imbalance in the centrifugal dehydrator based on the physical quantity, and it is preferable that the wear amount identification function identifies the wear amount of the tip of the screw based on the residual imbalance.

[0012] This configuration allows the residual imbalance to be identified along with the amount of wear.

[0013] In one aspect of the diagnostic system of the present invention, the measuring device includes a vibration sensor provided at least one on each of the two bearing portions, and the computing device is further capable of realizing a beat identification function that identifies the beat waveform of the centrifugal dehydrator based on the detection values ​​of the two vibration sensors, and it is preferable that the residual imbalance identification function identifies the residual imbalance based on the beat waveform.

[0014] According to this configuration, it is possible to diagnose whether or not there is residual imbalance, and to estimate the location of the cause of the imbalance.

[0015] In one aspect of the diagnostic system of the present invention, it is preferable that the computing device further realizes a health determination function that determines an index indicating the health of the centrifugal dehydrator based on the residual imbalance and the amount of wear.

[0016] This configuration makes it easy to see the need for maintenance of the centrifugal dehydrator.

[0017] In one aspect of the diagnostic system of the present invention, it is preferable that the calculation device, in the wear amount determination function, determines the radial wear amount of the inner barrel blade and the thickness-wise wear amount of the inner barrel blade.

[0018] According to this configuration, the amount of wear can be identified for typical types of wear that occur in centrifugal dehydrators, thereby increasing the accuracy of diagnosis.

[0019] Further features and advantages of the present invention will become more apparent from the following description of exemplary and non-limiting embodiments, which is given with reference to the drawings. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram showing a configuration of a centrifugal dehydrator according to an embodiment. [Figure 2] 1 is a block diagram showing a configuration of a diagnostic system according to an embodiment. [Figure 3] FIG. 1 is a flowchart showing the configuration of a diagnostic method according to an embodiment. [Figure 4] 10 is an example of an envelope according to an embodiment. [Figure 5] 5A and 5B are schematic diagrams illustrating a phase difference of acceleration detected in the embodiment. [Figure 6] FIG. 2 is a schematic diagram of a dynamic model according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Embodiments of a diagnostic system, a diagnostic method, and a diagnostic program according to the present invention will be described with reference to the drawings. In the following, an example will be described in which the present invention is applied to a diagnostic method for diagnosing a centrifugal dehydrator 100 using a diagnostic system 1. The diagnostic system 1 has installed therein a diagnostic program according to this embodiment.

[0022] [Configuration of centrifugal dehydrator] First, the configuration of the centrifugal dehydrator 100 to be diagnosed in this embodiment will be described. The centrifugal dehydrator 100 comprises an outer barrel 101 and an inner barrel 102 (FIG. 1). More specifically, the outer barrel 101 is a cylindrical body that rotates while housing a solid-liquid mixture, such as slurry-like sludge, to be separated, and is the part that performs solid-liquid separation by centrifugal force. The inner barrel 102 is implemented as a screw, and is the part that plays a role in transporting the solid-liquid mixture and the solid components after solid-liquid separation. A feed pipe is provided inside the shaft 102a of the inner barrel 102, and the solid-liquid mixture is supplied to the centrifugal dehydrator 100 through the feed pipe.

[0023] The outer barrel 101 and the inner barrel 102 are journaled by two bearings 103 (103a, 103b) provided at both ends in the extension direction (left-right direction in FIG. 1). The outer barrel 101 and the inner barrel 102 are rotated together by the driving force of a driver (not shown), and are given differential speeds by a differential speed device 104. This causes the outer barrel 101 and the inner barrel 102 to rotate at different rotation speeds.

[0024] The rotation speed of the inner barrel 102 is approximately 3 to 5 rpm higher than the rotation speed of the outer barrel 101. As a result, the inner barrel 102 (screw) rotates relatively faster than the outer barrel 101 (cylindrical body), and the solid-liquid mixture and solid components are gradually transported downstream (to the right in FIG. 1 ) by the inner barrel 102 inside the outer barrel 101. The rotation speed of the outer barrel 101 is set appropriately taking into consideration the properties of the material to be centrifuged and requirements from downstream processes, and can be, for example, 1500 to 3600 rpm. Furthermore, the rotation speed of the inner barrel 102 is set to a value approximately 3 to 5 rpm higher than the rotation speed of the outer barrel 101, depending on the rotation speed of the outer barrel 101.

[0025] In addition, in the downstream end region of the inner body 102, the thickness of the shaft 102a gradually increases from the upstream side to the downstream side, so that the space formed between the outer body 101 and the shaft 102a gradually decreases. As a result, in this end region, the solid components are compressed between the shaft 102a and the inner wall of the outer body 101, forming a dehydrated cake. The dehydrated cake is discharged from the downstream end of the centrifugal dehydrator 100. Meanwhile, the liquid components after solid-liquid separation are discharged from the upstream end of the centrifugal dehydrator 100. Note that, hereinafter, the side where the solid-liquid mixture is supplied (the left side in FIG. 1) is referred to as the "supply side," and the side where the dehydrated cake is discharged (the right side in FIG. 1) is referred to as the "discharge side." The supply side and the discharge side are at one end and the other end in the extension direction of the centrifugal dehydrator 100.

[0026] In the centrifugal dehydrator 100, the outer barrel 101 and inner barrel 102 rotate at high speed and come into contact with each other, causing wear on both components. Because wear does not necessarily occur evenly in the circumferential direction of the outer barrel 101 and inner barrel 102, the wear can cause residual imbalance in the centrifugal dehydrator 100. In other words, there is a close relationship between wear and residual imbalance.

[0027] [Configuration of diagnostic system] Next, the configuration of the diagnostic system 1 according to this embodiment will be described. The diagnostic system 1 according to this embodiment includes a vibration sensor 2 (an example of a measuring device), an outer barrel tachometer 3 (an example of a measuring device), an inner barrel tachometer 4 (an example of a measuring device), and a computing device 5 (FIG. 2). One vibration sensor 2 is provided for each of the two bearings 103a and 103b. To distinguish between them, the one provided for the supply-side bearing 103a will be referred to as vibration sensor 2a, and the one provided for the discharge-side bearing 103b will be referred to as vibration sensor 2b.

[0028] The vibration sensor 2 may be a known sensor capable of converting vibrations into an electrical signal. Examples of sensors that can be used include an acceleration sensor, a velocity sensor, and a non-contact displacement sensor. While the two vibration sensors 2a and 2b may be different types of sensors, it is preferable that the two vibration sensors 2a and 2b be the same type of sensor, from the viewpoint of facilitating procurement of components and calculation processing. For the sake of explanation, the following describes an example in which both the two vibration sensors 2a and 2b are acceleration sensors, but the diagnostic system 1 according to this embodiment will also be effective when other types of vibration sensors are used.

[0029] The vibration sensor 2 is electrically connected to the arithmetic device 5 and is configured to be able to input a measured value to the arithmetic device 5. The vibration sensor 2 may input the measured physical quantity value itself to the arithmetic device 5, or may input a value that has been subjected to some processing to the arithmetic device 5.

[0030] As an example of a configuration capable of such processing, the vibration sensor 2 may have a filter circuit. In this case, the measurement value output from the vibration sensor 2 becomes extracted data obtained by extracting a specific frequency range determined according to the characteristics of the filter circuit from the measurement value itself caused by the vibration of the centrifugal dehydrator 100. The characteristics of the filter circuit are preferably determined taking into consideration the rotation speed of the outer body 101 and the rotation speed of the inner body 102.

[0031] The outer barrel rotation meter 3 is a rotation meter that measures the rotation speed of the outer barrel 101, and a known rotation meter can be used. Note that if the centrifugal extractor 100 originally has a rotation meter that measures the rotation speed of the outer barrel 101, instead of providing the outer barrel rotation meter 3 in the diagnostic system 1, a signal line may be connected so that the output value of the rotation meter that the centrifugal extractor 100 originally has is input to the computing device 5.

[0032] The inner barrel rotation counter 4 is a rotation counter that measures the rotation speed of the inner barrel 102, and a known rotation counter can be used. The measurement methods of the outer barrel rotation counter 3 and the inner barrel rotation counter 4 may be the same or different. If the centrifugal dehydrator 100 is equipped with a rotation counter that measures the rotation speed of the inner barrel 102, like the outer barrel rotation counter 3, this may be used in place of the inner barrel rotation counter 4.

[0033] The arithmetic device 5 is a terminal including an arithmetic device 51, a storage device 52, an input terminal 53, a display 54, and an input device 55. The arithmetic device 5 may be a dedicated terminal having a configuration known in the technical field of this type of diagnostic device, measuring device, etc., or may be a general-purpose information terminal such as a personal computer, a tablet terminal, or a smartphone.

[0034] The arithmetic device 51 is configured to be able to execute various arithmetic processes related to the diagnostic method and diagnostic program according to this embodiment, and is implemented as a known CPU. The storage device 52 is a storage device capable of storing various data handled by the arithmetic device 5, and is implemented as a magnetic memory such as a hard disk drive (HDD) or a semiconductor memory such as a solid-state drive (SSD). The input terminal 53 is a terminal electrically connected to the vibration sensors 2 (2a, 2b), the outer barrel rotation counter 3, and the inner barrel rotation counter 4, and vibration waveform data is input to the arithmetic device 5 through the input terminal 53. The input signals of the vibration sensor 2, the outer barrel rotation counter 3, and the inner barrel rotation counter 4 input to the input terminal 53 are synchronized.

[0035] The display 54 and the input device 55 are components that function as a user interface unit of the arithmetic unit 5. The display 54 is provided for the purpose of displaying various data handled by the arithmetic unit 5 and presenting (outputting) information to the user, and is implemented as a known liquid crystal display or the like. The input device 55 is provided for the purpose of accepting various input operations from the user to the arithmetic unit 5, and is implemented as a keyboard, mouse, button, touch panel, or the like.

[0036] [Functions of the arithmetic unit] In the diagnostic system 1 according to this embodiment, the arithmetic device 5 can realize an acquisition function, a beat identification function, a residual imbalance identification function, a wear amount identification function, and a soundness identification function. Note that the execution entity of each operation described below is the arithmetic device 5 unless otherwise specified. Furthermore, each function corresponds to each step of the diagnostic method according to the present invention.

[0037] In the following, an example will be described in which the rotation speed of the outer body 101 is 3600 rpm and the rotation speed of the inner body 102 is 3603 rpm. In the description, a description to the effect that the rotation speed of the centrifugal dehydrator 100 is approximately 3600 rpm will be used.

[0038] (1) Acquisition function (acquisition process S10) The acquisition function is a function for acquiring vibration waveform data resulting from vibration of the centrifugal dehydrator 100, the rotation speed of the outer barrel 101, and the rotation speed of the inner barrel 102. Specifically, the measured values ​​measured by the vibration sensors 2 (2a, 2b), the outer barrel tachometer 3, and the inner barrel tachometer 4 are input to the calculation device 5. Note that these measured values ​​are all obtained by measuring physical quantities related to the centrifugal dehydrator 100. The measured value of the vibration sensor 2 is obtained, for example, by measuring acceleration (an example of a physical quantity), and the measured values ​​of the outer barrel tachometer 3 and the inner barrel tachometer 4 are obtained, for example, by measuring the current value (an example of a physical quantity) of a photoelectric rotation detector.

[0039] (2) Beat Identification Function (Beat Identification Step S20) The beat identifying function is a function for identifying the waveform of the beat of the centrifugal dehydrator 100 based on the detected values ​​of the two vibration sensors 2.

[0040] Beating occurs during operation of the centrifugal extractor 100 due to the difference in rotation speed between the outer shell 101 and the inner shell 102. The beat period, which is the cycle of this beat, is determined as 60 seconds divided by the difference in rotation speed between the outer shell 101 and the inner shell 102, and is approximately 12 to 20 seconds. As a result, the intensity of the vibration of the centrifugal extractor 100 changes periodically with a period of approximately 12 to 20 seconds. As described above, taking the example where the rotation speed of the outer shell 101 is 3600 rpm and the rotation speed of the inner shell 102 is 3603 rpm, the difference in rotation speed between the outer shell 101 and the inner shell 102 is 3 rpm, and the beat period can theoretically be derived as 20 seconds.

[0041] In the beat identification function according to this embodiment, an envelope of the vibration waveform data (a plot in which the horizontal axis represents time and the vertical axis represents the measured values ​​of the vibration sensor 2) is identified (S21), and a feature value is extracted from the envelope (S22). In this embodiment, the envelope identification (S21) and the feature value extraction (S22) are executed for each of the measured values ​​of the vibration sensor 2a (supply side) and the vibration sensor 2b (discharge side).

[0042] The centrifugal extractor 100 vibrates at a period of approximately 17 milliseconds (60 seconds ÷ 3600 ≒ 0.017 seconds), corresponding to a rotation speed of approximately 3600 rpm. The envelope of the vibration waveform data, which vibrates at a period of approximately 17 milliseconds, can be determined by performing a Hilbert transform on the vibration waveform data or by connecting the points in each period where the absolute value is maximum (Figure 4).

[0043] The vibration waveform data acquired by the acquisition function itself contains components such as noise in addition to components caused by the vibration of the centrifugal dehydrator 100. Therefore, a filtering process may be performed to extract extracted data from the vibration waveform data within a predetermined frequency range that includes a rotational frequency (approximately 60 Hz) determined based on the rotational speed of the outer body 101 and the rotational speed of the inner body 102 (rotational speed of the centrifugal dehydrator 100: approximately 3600 rpm). The filtering process may be bandpass filtering. In this case, an envelope is determined for the extracted data obtained by the filtering process.

[0044] It should be noted that if the vibration sensor 2 has a filter circuit and filtered extracted data is input from the vibration sensor 2 to the arithmetic unit 5, envelope processing is performed on the extracted data. In other words, extraction of the extracted data may be performed by hardware in the vibration sensor 2, or by software in the arithmetic unit 5.

[0045] Next, based on the identified envelope, various feature values ​​are extracted for use in the calculation process of the residual imbalance identification function. First, the beat period is extracted. The envelope shows a waveform that oscillates at a constant period, and this period coincides with the beat period. Second, the maximum value V1 and minimum value V2 of the amplitude in the identified envelope are extracted.

[0046] (3) Residual imbalance identification function (residual imbalance identification step S30) The residual imbalance identification function is a function that identifies the residual imbalance of the centrifugal extractor 100 based on the envelope identified in the beat identification function and the characteristic values ​​of the envelope. The procedure roughly includes identifying the amplitude (S31), identifying the phase difference (S32), and applying a dynamic model (S33).

[0047] (3-1) Identifying the amplitude As described above, the beat of the centrifugal extractor 100 is caused by the difference in rotation speed between the outer shell 101 and the inner shell 102. This phenomenon can be explained as follows: when the residual unbalance of the outer shell 101 and the residual unbalance of the inner shell 102 are close in phase, the vibrations caused by both act additively, resulting in increased vibration; when the phases are far apart, the vibrations caused by both act to cancel each other out, resulting in decreased vibration. Therefore, in the envelope identified by the beat identification function, the point at which the amplitude reaches its maximum value V1 is the point at which the phases of the residual unbalance of the outer shell 101 and the residual unbalance of the inner shell 102 match, and the point at which the amplitude reaches its minimum value V2 is the point at which the phase difference is 180°.

[0048] Here, the amplitude a B , angular velocity ω B The component due to the residual imbalance of the inner body 102 has an amplitude a S , angular velocity ω S Then, the acceleration A detected by the vibration sensor 2 is expressed as a function of time t by the following equation (1).

number

[0049] The envelope curve identified by the beat identification function is obtained by sequentially connecting the points where the absolute value is maximum in each cycle of the waveform expressed by equation (1). Therefore, the maximum value V1 and minimum value V2 of the envelope amplitude are expressed by the following equations (2) and (3), respectively.

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[0050] Equation (3) is a B and a S The cases are divided as follows depending on the magnitude relationship with

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[0051] Therefore, a B >a S When this happens, from the simultaneous equations of equation (2) and equation (3-1), a B and a S is specified as follows:

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[0052] Similarly, a B S When this happens, from the simultaneous equations of equation (2) and equation (3-1), a B and a S is specified as follows:

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[0053] That is, a B and a S If the magnitude relationship between V1 and V2 can be determined, the amplitudes V1 and V2 can be calculated based on the maximum amplitudes V1 and V2 extracted from the envelope. B and a S However, from the envelope itself, a B and a S Since it is not possible to determine the magnitude relationship between the two, a process for determining this is required.

[0054] Therefore, in this embodiment, the amplitude is set to the minimum value V2 of the envelope, and the angular velocity is set to ω B Let us consider a hypothetical waveform A. i The minimum value V2 of the envelope is extracted from the envelope, and the angular velocity ω B ​can be determined from the rotation speed of the outer shell 101, so either can be determined. The rotation speed of the outer shell 101 used at this time may be an actual measurement value obtained by the outer shell rotation meter 3, or a rough value based on the operating conditions (3600 rpm in this embodiment). In either case, from the information available at this point, the virtual waveform A i In the following, a case where the actual measured value of the rotation speed of the outer case 101 is used will be explained. i is expressed by the following equation (6).

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[0055] Next, acceleration A detected by vibration sensor 2 and virtual waveform A i The waveform obtained by adding these is expressed by the following equation (7).

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[0056] Here, equation (3) is substituted into equation (7).

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[0057] a B >a S When V2=a B -a S (Equation (3-1)), so Equation (8) can be transformed as follows:

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[0058] Considering the time when the amplitude of the envelope takes the minimum value V2, the component due to the residual unbalance of the outer body 101 and the component due to the residual unbalance of the inner body 102 are in opposite phases at this time, so sin(ω B t)=-sin(ω S t). Therefore, equation (8-1) can be further transformed as follows:

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[0059] The right side of equation (8-2) is nothing but twice the acceleration A (equation (1)) detected by the vibration sensor 2. Therefore, a B >a S When , acceleration A is virtual waveform A i When a rough value is used as the rotation speed of the outer case 101, the minimum value V2 of the envelope curve becomes approximately doubled.

[0060] On the other hand, a B S When V2=a S -a B (Equation (3-2)), so Equation (8) can be transformed as follows:

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[0061] a B >a S Similarly, when the amplitude of the envelope takes the minimum value V2, sin(ω B t)=-sin(ω S Using t), equation (8-3) can be further transformed as follows:

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[0062] From equation (8-4), a B S When , acceleration A is virtual waveform A i By performing the process of adding, a phenomenon is observed in which the minimum value V2 of the envelope curve becomes 0. Note that when a rough value is used as the rotation speed of the outer case 101, the minimum value V2 of the envelope curve becomes approximately 0.

[0063] ​​The above process can be summarized as follows: for the specified envelope, the minimum value V2 of the amplitude extracted from the envelope and the angular velocity ω specified from the rotation speed of the outer body 101 are B Virtual waveform A created from i When adding, the minimum amplitude of the summed waveform will be twice the minimum value V2 of the original envelope, or 0. Based on this difference in behavior, a B and a S In other words, when the minimum value of the amplitude of the added waveform is twice the minimum value V2 of the original envelope, B >a S When the minimum amplitude of the summed waveform becomes 0, B S is.

[0064] In this way, virtual waveform A i Using a B and a S Therefore, using equations (4-1) and (5-1), or equations (4-2) and (5-2), B and a S can be identified.

[0065] In the above example, virtual waveform A i The angular velocity of ω B Instead, we use the virtual waveform A i The angular velocity of ω S In this case, the angular velocity ω S You can use actual measured values ​​or approximate values. In this case, contrary to the above case, B >a S When equation (8-4) holds, a B S Equation (8-2) holds when

[0066] The above processing is performed for each envelope curve determined from the measured values ​​of the vibration sensor 2a (supply side) and the vibration sensor 2b (discharge side). As a result, the amplitude a of the component of the acceleration on the supply side caused by the residual imbalance of the outer shell 101 is calculated. Bk ​​, the amplitude a of the component of the acceleration on the discharge side due to the residual unbalance of the outer shell 101 Bh , the amplitude a of the component of the supply side acceleration due to the residual imbalance of the inner body 102 Sk , and the amplitude a of the component of the discharge side acceleration due to the residual imbalance of the inner body 102 Sh , is identified.

[0067] (3-2) Identifying the phase difference Using the four amplitudes identified as above to express the sensor direction components of acceleration, the supply-side acceleration A1 and discharge-side acceleration A2 caused by the residual imbalance of the outer body 101, and the supply-side acceleration A3 and discharge-side acceleration A4 caused by the residual imbalance of the inner body 102 can be expressed as follows: where Δφ is the phase difference between the supply side and discharge side of the acceleration caused by the residual imbalance of the outer body 101, and Δξ is the phase difference between the supply side and discharge side of the acceleration caused by the residual imbalance of the inner body 102.

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[0068] Also, the acceleration A detected by the vibration sensor 2a on the supply side k and acceleration A detected by the vibration sensor 2b on the discharge side h are expressed as follows: Acceleration A k , A h is measured by the vibration sensors 2a and 2b. k is the amplitude a k is the acceleration measured by the vibration sensor 2a for the wave of acceleration A h is the amplitude a h is the acceleration measured by the vibration sensor 2b for the wave.

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[0069] Acceleration A kWhen considering the moment when sin(ω) reaches its maximum, it corresponds to the moment when the component due to the residual unbalance of the outer body 101 on the supply side and the component due to the residual unbalance of the inner body 102 arrive at the sensor installation position in the same phase. B t)=sin(ω S t) = 1. The relationship between the acceleration and phase of the outer and inner barrels on the supply and discharge sides at this time is shown in Figure 5. Note that Δθ in the figure is the phase difference between the acceleration of the outer and inner barrels on the discharge side, and is determined as the phase difference of the envelopes determined from the measured values ​​of the vibration sensors 2a and 2b.

[0070] Acceleration on the discharge side a h and the acceleration a h The component of the acceleration a resulting from the residual imbalance of the inner body 102 Bh The phase difference between B Then, the following formula holds:

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[0071] From equations (10-1) and (10-2), the following equation (11) is derived.

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[0072] Also, acceleration A k and acceleration A h Phase difference Δθ D Calculate the acceleration A. k The period of the waveform is t B and the acceleration A k The time when the acceleration at the sensor position is maximum and the acceleration A h The difference between the time when the acceleration at the sensor position becomes maximum and the time when the acceleration at the sensor position becomes maximum is Δt, and Δθ D is given by the following equation (12).

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[0073] The phase difference Δφ between the supply side and discharge side of the acceleration caused by the residual imbalance of the outer body 101 and the phase difference Δξ between the supply side and discharge side of the acceleration caused by the residual imbalance of the inner body 102 are given by the following equations, respectively.

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[0074] (3-3) Application of mechanical models The diagnostic function assumes a dynamic model (FIG. 6) in which one load exists on each of the supply and discharge sides of the outer shell 101 and the inner shell 102, and identifies the masses of the four loads in the dynamic model. In other words, rather than identifying the actual location or size of the causes of residual imbalance (such as adhesion or damage), the diagnostic function identifies the residual imbalance of the centrifugal dehydrator 100 by using a model in which these causes are represented by the four loads.

[0075] In the dynamic model (Fig. 6), a load 61 placed on the supply side of the outer shell 101 and a load 62 placed on the discharge side, as well as a load 63 placed on the supply side of the inner shell 102 and a load 64 placed on the discharge side, are set. The parameters of the loads 61 to 64 are represented by the symbols shown in the table below. However, the masses m B1 , m B2 , m S1 , m S2 The parameters other than are constants that are determined in advance when the dynamic model is set. k and the mass on the discharge side is M h and the total length is L0.

[0076] Table 1: Symbols representing the load parameters on the mechanical model [Table 1]

[0077] When this mechanical model is solved with the premise that the excitation forces are balanced, the following solution is obtained:

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[0078] That is, the acceleration A detected by the vibration sensor 2 (2a, 2b) k , A h and the angular velocity ω converted from the number of rotations detected by the outer barrel rotation meter 3. B and the angular velocity ω converted from the number of rotations detected by the inner barrel rotation meter 4. S and the amplitude a of the component of the supply side acceleration due to the residual unbalance of the outer shell 101 is calculated using Bk , the amplitude a of the component of the acceleration on the discharge side due to the residual unbalance of the outer shell 101 Bh , the amplitude a of the component of the supply side acceleration due to the residual imbalance of the inner body 102 Sk , and the amplitude a of the component of the discharge side acceleration due to the residual imbalance of the inner body 102 Sh , and the phase difference Δφ between the supply side and discharge side of the acceleration due to the residual unbalance of the outer body 101 and the phase difference Δξ between the supply side and discharge side of the acceleration due to the residual unbalance of the inner body 102 are identified, and by substituting these into equations (15-1) to (15-4), the mass m B1 , m B2 , m S1 , m S2 The mass m of the loads 61 to 64 determined at this time can be determined. B1 , m B2 , m S1 , m S2 can be said to represent the residual imbalance currently present in the centrifugal extractor 100.

[0079] Determined mass m B1 , m B2 , m S1 , m S2 From this, the magnitude relationship of the residual imbalance in the four divided regions on the supply side and discharge side of the outer shell 101 and inner shell 102, as well as the overall degree of residual imbalance of the centrifugal dehydrator 100, can be identified.

[0080] (4) Wear Amount Identification Function (Wear Amount Identification Step S40) The wear amount determination function is a function for determining the amount of wear at the tip of the inner body 102 (screw) in the centrifugal dehydrator 100 based on the residual imbalance determined by the residual imbalance determination function. In this embodiment, the residual imbalance (mass m S2 ) and the amount of wear is determined based on the measured value. The reason for targeting the inner body 102 is that the inner body 102 is more susceptible to wear than the outer body 101. The reason for targeting the discharge side is that the residual imbalance on the discharge side is often caused by wear, whereas the residual imbalance on the supply side is often caused by sludge adhesion or the like.

[0081] In this embodiment, a first determination is made assuming that the residual imbalance is entirely caused by radial wear of the blades of the inner barrel 102, and a second determination is made assuming that the residual imbalance is entirely caused by wear in the thickness direction of the blades of the inner barrel 102. In reality, the blades of the inner barrel 102 wear in both the radial and thickness directions, so it is incorrect to assume that the residual imbalance is entirely caused by wear in one direction. However, by assuming that the residual imbalance is entirely caused by wear in one direction, as described above, it is possible to calculate the maximum possible value of wear in that direction. Thus, the wear amounts determined in this embodiment are all hypothetical values ​​based on extreme assumptions.

[0082] By determining the amount of wear based on the extreme assumption that wear has progressed excessively in one direction and using this as a reference to determine the soundness of the centrifugal extractor 100, it is possible to detect signs of malfunction in the centrifugal extractor 100. Even if the soundness of the centrifugal extractor 100 is doubted under such an assumption, in an actual centrifugal extractor 100, the assumed amount of wear occurs dispersedly in both the radial and thickness directions, so the deterioration in soundness is minor. This makes it possible to take measures such as planning maintenance while the malfunction of the centrifugal extractor 100 is still minor.

[0083] In the first determination, first, the amount of uneven wear W when it is assumed that the entire cause of the residual imbalance is due to uneven wear in the radial direction of the blade of the inner cylinder 102 is a(Equation (16)) constant γ r is determined from the mechanical conditions (dimensions, material, density, etc.) of the inner body 102.

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[0084] In addition, when it is assumed that the cause of the residual imbalance is entirely due to the radial wear of the blade of the inner cylinder 102, the total wear amount W b is determined (Equation (17)). The constant λ is an experimentally determined constant.

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[0085] In the second specification, the wear amount W when it is assumed that the cause of the residual imbalance is entirely due to wear in the thickness direction of the blade of the inner cylinder 102 c Identify (Equation (18-1)).

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[0086] constant γ t is determined from the mechanical conditions (dimensions, material, density, etc.) of the inner body 102. That is, the constant γ t The determining factor is the constant γ r Therefore, the wear amount Wc is determined by the constant γ r The constant k may be determined from the mechanical conditions of the inner body 102 (dimensions, material, density, etc.).

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[0087] (5) Soundness identification function (soundness identification process S50) The soundness determination function is a function that determines an index (soundness index) indicating the soundness of the centrifugal dehydrator 100 based on the residual imbalance determined by the residual imbalance determination function and the amount of wear determined by the amount of wear determination function. The soundness index is determined for each of the outer body 101 and the inner body 102.

[0088] For the outer shell 101, a soundness index is determined based on the residual imbalance. Here, the residual imbalance (mass m B1 ) and residual imbalance at the discharge side (mass m B2 ) is used. The following explanation will be given using the supply side as an example.

[0089] First, mass m B1 Substituting this into equation (19), balance grade G based on JIS B 0905:1992 is obtained. B1 The constant β is determined based on the mechanical conditions (dimensions, material, density, etc.) of the outer shell 101, and the constant m 0B1 is the residual imbalance on the supply side of the outer shell 101 at the time of initial manufacture of the centrifugal dehydrator 100 (i.e., the initial value of the residual imbalance). B1 Instead, mass m B1 A moving average value of may be used.

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[0090] Next, the calculated balance grade G B1 The health index H B1 Convert to balance class G B1 and health index H B1 A correspondence relationship between the health index H B1 When expressed as five levels from 1 to 5, the balance grade G for each level is B1 The numerical range is set. The calculated balance grade G B1 By comparing the value of with the numerical range of each level, the soundness index H B1The higher the soundness index value, the higher the soundness.

[0091] The same process is carried out on the discharge side, and mass m B2 Balance grade G B2 After converting this to the health index H B2 Conversion to balance class G B2 and health index H B2 The correspondence relationship between the supply side and the supply health index H may be the same as or different from that of the supply side. B1 and the discharge side health index H B2 The lower value is used as the soundness index H of the outer shell 101. B It is determined as follows.

[0092] For the inner barrel 102, a soundness index is determined based on the residual imbalance and the amount of wear. Here, the residual imbalance (mass m S1 ), and the radial wear amount W on the discharge side b and wear amount W in the thickness direction c That is, for the supply side, a health index is determined based on the residual imbalance, and for the discharge side, a health index is determined based on the amount of wear.

[0093] The supply side is the same as that of the outer shell 101. That is, mass m S1 Balance grade G S1 After converting this to the health index H S1 Conversion to balance class G S1 and health index H S1 The correspondence between the outer shell 101 and the outer shell 102 may be the same as that between the outer shell 101 and the outer shell 102, or may be different.

[0094] On the discharge side, the wear amount W b , W c Based on the predetermined correspondence between the wear amount W and the soundness index, b , W cThis correspondence is stored in the storage device 52. For example, if the health index is expressed in five levels from 1 to 5, the wear amount W b , W c The numerical range of the wear amount W is set. b , W c By comparing the value of with the numerical range of each level, the radial wear amount W b Health index H based on Sr2 and the wear amount in the thickness direction W c Health index H based on St2 The correspondence between the wear amount and the soundness index may be the same in the radial direction and the thickness direction, or may be different.

[0095] And the supply-side health index H S1 , and the discharge side health index H Sr2 and health index H St2 The lowest value is the soundness index H of the inner hull 102. S It is determined as follows.

[0096] Outer hull 101 soundness index H B and the soundness index H of the inner shell 102 S By tracking the changes in the temperature, it is possible to detect abnormal trends in the centrifugal dehydrator 100, thereby enabling timely maintenance.

[0097] Other Embodiments Finally, other embodiments of the diagnostic system, diagnostic method, and diagnostic program according to the present invention will be described. Note that the configurations disclosed in the following embodiments can be applied in combination with the configurations disclosed in other embodiments, as long as no contradiction occurs.

[0098] In the above embodiment, the diagnostic system 1 includes a vibration sensor 2, an outer barrel rotation counter 3, and an inner barrel rotation counter 4, and the residual unbalance is identified based on the physical quantities measured by these measuring devices. However, the present invention does not limit the physical quantities measured to identify the residual unbalance. Furthermore, when a vibration sensor is used as the measuring device, the method for identifying the residual unbalance is not limited to the method of identifying beats exemplified above.

[0099] In the above embodiment, the wear amount determining function is described as an example of a configuration in which the wear amount of the tip of the inner body 102 (screw) is determined based on the residual imbalance determined by the residual imbalance determining function. However, the aspect of the wear amount determining function in the present invention is not limited as long as it determines the wear amount of the tip of the screw based on a physical quantity related to the centrifugal extractor.

[0100] In the above embodiment, the diagnostic system 1 is configured to be able to realize the health level identification function, but in the present invention, it is optional whether or not to identify the health level.

[0101] Regarding other configurations, it should be understood that the embodiments disclosed in this specification are illustrative in all respects and that the scope of the present invention is not limited thereby. Those skilled in the art will easily understand that appropriate modifications are possible without departing from the spirit of the present invention. Therefore, other embodiments modified without departing from the spirit of the present invention are naturally included in the scope of the present invention. [Industrial Applicability]

[0102] The present invention can be used to diagnose centrifugal dehydrators used for sludge treatment and the like. [Explanation of symbols]

[0103] 1: Diagnostic system 2: Vibration sensor 3: Outer barrel rotation counter 4: Inner body rotation meter 5: Arithmetic device 51: Computing device 52: Storage device 53: Input terminal 54: Display 55: Input device 100: Centrifugal dehydrator 101: Outer body 102: Inner body 103: Bearing part

Claims

1. A diagnostic system for diagnosing a centrifugal dehydrator, comprising an outer barrel and an inner barrel that are concentrically arranged, journaled by two bearings provided at both ends in an extension direction, and that rotate at different rotation speeds, the inner barrel having a screw helically provided on its outer periphery, a measuring device for measuring a physical quantity related to the centrifugal dehydrator; a computing device, The diagnostic system is capable of realizing a wear amount specifying function that specifies the amount of wear at the tip of the screw based on the physical quantity.

2. The computing device A residual imbalance identification function for identifying a residual imbalance of the centrifugal dehydrator based on the physical quantity can be further realized, The diagnostic system according to claim 1 , wherein the wear amount identifying function identifies the amount of wear at the tip of the screw based on the residual imbalance.

3. the measuring device includes a vibration sensor provided in each of the two bearing portions, The computing device A beat identifying function for identifying the beat waveform of the centrifugal dehydrator based on the detected values ​​of the two vibration sensors can be further realized, 3. The diagnostic system according to claim 2, wherein the residual imbalance identifying function identifies the residual imbalance based on a waveform of the beat.

4. The diagnostic system according to claim 2 , wherein the computing device is further capable of realizing a health determination function of determining an index indicating the health of the centrifugal dehydrator based on the residual imbalance and the amount of wear.

5. The diagnostic system according to claim 1 , wherein the wear amount specifying function is configured to specify the wear amount in the radial direction of the screw and the wear amount in the thickness direction of the tip of the screw.

6. A diagnostic method for diagnosing a centrifugal dehydrator comprising an outer barrel and an inner barrel that are concentrically arranged, journaled by two bearings provided at both ends in an extension direction, and that rotate at different rotation speeds, the inner barrel having a screw helically provided on its outer periphery, the method comprising: a measuring step of measuring a physical quantity related to the centrifugal dehydrator; The diagnostic method includes a wear amount specifying step of specifying the amount of wear at the tip portion of the screw based on the physical quantity.

7. A diagnostic program for diagnosing a centrifugal dehydrator, comprising an outer barrel and an inner barrel that are concentrically arranged, journaled by two bearings provided at both ends in an extension direction, and that rotate at different rotation speeds, the inner barrel having a screw that is spirally provided on its outer periphery, When executed by a computer, a physical quantity acquisition function for acquiring physical quantities related to the centrifugal dehydrator; a diagnostic program capable of realizing a wear amount specifying function for specifying the wear amount of the tip portion of the screw based on the physical amount;

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