Diagnostic device, diagnostic method, and diagnostic program

Abstract

To identify the presence of abnormality, and estimate a position thereof.SOLUTION: Provided is a diagnosis device for diagnosing a centrifugal dehydrator 100 that is pivotally supported by two bearings 103a, 103b that are concentrically arranged and provided at both ends in an extension direction, and that is equipped with an outer shell 101 and an inner shell 102 rotating at mutually different revolution speeds. The diagnosis device comprises vibration sensors 2a, 2b that are provided to the two bearings 103a, 103b, at least one for each, and a computing device. The computing device is capable of identifying a beat waveform of the centrifugal dehydrator 100 that is an object to be diagnosed, on the basis of detection values of the two vibration sensors 2a, 2b, and identifying the residual imbalance of the centrifugal dehydrator 100 on the basis of the beat waveform.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] As a method for diagnosing devices having a rotary drive unit, a commonly used method focuses on vibrations generated during the operation of the device and performs diagnosis based on electrically measured vibration waveforms. For example, Japanese Patent Publication No. 8-122305 (Patent Document 1) discloses a bearing abnormality diagnostic device that measures acoustic emissions (AE) generated by a bearing with an AE sensor and diagnoses bearing abnormalities based on the AE signal output by the AE sensor. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-122305 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, while the technology described in Patent Document 1 could determine whether or not there was a bearing abnormality, it could not estimate the location of that abnormality. Therefore, even if the device was disassembled and serviced when an abnormality was detected, the cause of the abnormality had to be investigated by examining the entire device, which sometimes resulted in a long time being spent to resolve the problem.

[0005] Therefore, there is a need for a diagnostic device, diagnostic method, and diagnostic program that can not only identify the presence or absence of an abnormality but also estimate its location. [Means for solving the problem]

[0006] The diagnostic device according to the present invention is for diagnosing a centrifugal dewatering machine having an outer and inner drum that are arranged concentrically, supported by two bearing sections located at both ends in the extending direction, and rotating at different rotational speeds, and comprises a vibration sensor provided at least one on each of the two bearing sections, and a calculation device, wherein the calculation device identifies the waveform of the hum of the centrifugal dewatering machine based on the detected values ​​of the two vibration sensors. death Furthermore, the residual unbalance of the centrifugal dehydrator is identified based on the waveform of the aforementioned hum. do It is characterized by the following:

[0007] The diagnostic method according to the present invention is a diagnostic method for diagnosing a centrifugal dewatering machine comprising an outer shell and an inner shell arranged concentrically and supported by two bearing portions provided at both ends in the extending direction, and rotating at different rotational speeds, and is characterized by comprising the steps of: identifying the waveform of the hum of the centrifugal dewatering machine to be diagnosed based on the detection value of a vibration sensor provided at least one at each of the two bearing portions; and identifying the residual unbalance of the centrifugal dewatering machine based on the waveform of the hum.

[0008] The diagnostic program according to the present invention is a diagnostic program for diagnosing a centrifugal dewatering machine comprising an outer and inner drum that are arranged concentrically, supported by two bearing parts provided at both ends in the extending direction, and rotating at different rotational speeds, and is characterized in that, when executed by a computer, it realizes the function of identifying the waveform of the hum of the centrifugal dewatering machine to be diagnosed based on the detection value of vibration sensors provided at least one at each of the two bearing parts, and the function of identifying the residual unbalance of the centrifugal dewatering machine based on the waveform of the hum.

[0009] With these configurations, it is possible to diagnose the presence or absence of residual unbalance and estimate the location of its cause based on the detection values ​​of vibration sensors provided at least one at each of the two bearing sections.

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

[0011] In one embodiment of the diagnostic device according to the present invention, it is preferable that the calculation device uses the detected values ​​of the two vibration sensors to solve a mechanical model of a centrifugal dehydrator in which residual unbalance is set at a predetermined position, and obtains a solution in which the residual unbalance in the mechanical model represents the actual residual unbalance, thereby identifying the residual unbalance of the centrifugal dehydrator to be diagnosed.

[0012] This configuration allows for a reduction in computational processing load because the detected values ​​are applied to a pre-defined dynamic model to obtain a solution.

[0013] In one embodiment, the diagnostic device according to the present invention separates the residual unbalance of the centrifugal dehydrator to be diagnosed into the residual unbalance of the outer drum of the centrifugal dehydrator and the residual unbalance of the inner drum of the centrifugal dehydrator. do It is preferable.

[0014] This configuration allows for the diagnosis of residual imbalance in both the outer and inner shells, as well as the estimation of the location of its cause.

[0015] In one embodiment, the diagnostic device according to the present invention determines the phase difference between residual unbalance located at one end of the centrifugal dehydrator in the extending direction and residual unbalance located at the other end in the extending direction. do It is preferable.

[0016] This configuration allows for a more detailed identification of the positional relationship between the residual imbalances of the outer and inner shells.

[0017] In one embodiment, the diagnostic device according to the present invention further includes a calculation device that identifies the envelope of the hum waveform of the centrifugal dehydrator to be diagnosed. do It is preferable.

[0018] This configuration allows for a reduction in the number of data points to be processed compared to when envelope processing is not performed, thereby reducing the computational load.

[0019] In one embodiment, the diagnostic device according to the present invention generates a virtual waveform in which the angular velocity is the same as the angular velocity of the outer drum or the angular velocity of the inner drum, and the amplitude is greater than 0 and less than or equal to the minimum amplitude of the envelope; generates an added waveform obtained by adding the virtual waveform and the envelope; and separates the residual unbalance of the centrifugal dehydrator to be diagnosed into the residual unbalance of the outer drum of the centrifugal dehydrator and the residual unbalance of the inner drum of the centrifugal dehydrator based on the added waveform. do It is preferable.

[0020] With this configuration, it is possible to diagnose the presence or absence of residual imbalance in the outer and inner shells, respectively, and to estimate the location of the cause, through relatively simple calculations.

[0021] In one embodiment, the diagnostic device according to the present invention further comprises an outer drum tachometer for measuring the rotational speed of the outer drum of a centrifugal dehydrator to be diagnosed, and an inner drum tachometer for measuring the rotational speed of the inner drum of the centrifugal dehydrator, wherein the calculation device identifies the residual unbalance of the centrifugal dehydrator to be diagnosed based on the hum waveform, the rotational speed of the outer drum, and the rotational speed of the inner drum. do It is preferable.

[0022] With this configuration, based on the detection values ​​of vibration sensors provided at least one at each of the two bearing sections, the rotational speed of the outer casing, and the rotational speed of the inner casing, it is possible to distinguish between one end and the other end in the extending direction of the outer casing and inner casing, as well as the location of the cause of residual unbalance, and to identify the phase difference between one end and the other end.

[0023] Further features and advantages of the present invention will become clearer through the following description of exemplary and non-limiting embodiments, with reference to the drawings. [Brief explanation of the drawing]

[0024] [Figure 1] This is a diagram showing the configuration of a centrifugal dehydrator according to an embodiment. [Figure 2]This is a block diagram showing the configuration of the diagnostic device according to the embodiment. [Figure 3] This is a flowchart showing the configuration of the diagnostic method according to the embodiment. [Figure 4] This is an example of an envelope according to the embodiment. [Figure 5] This is a schematic diagram showing the phase difference of acceleration detected in the embodiment. [Figure 6] This is a schematic diagram of the mechanical model according to the embodiment. [Modes for carrying out the invention]

[0025] Embodiments of the diagnostic device, diagnostic method, and diagnostic program according to the present invention will be described with reference to the drawings. Below, an example will be described in which the diagnostic method, diagnostic program, and diagnostic device according to the present invention are applied to a diagnostic method for diagnosing a centrifugal dehydrator 100 using the diagnostic device 1. The diagnostic program according to this embodiment is installed on the diagnostic device 1.

[0026] [Configuration of a centrifugal dehydrator] First, the configuration of the centrifugal dewatering machine 100, which is the target of diagnosis by the diagnostic method, diagnostic program, and diagnostic device according to this embodiment, will be described. The centrifugal dewatering machine 100 comprises an outer shell 101 and an inner shell 102 (Figure 1). More specifically, the outer shell 101 is a cylindrical body that rotates while containing 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 shell 102 is implemented as a screw and is the part that plays the role of 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 shell 102, and the solid-liquid mixture is supplied to the centrifugal dewatering machine 100 through the feed pipe.

[0027] The outer casing 101 and the inner casing 102 are pivotally supported at two bearing sections 103 (103a, 103b) located at both ends in the extending direction (left-right direction in Figure 1). The outer casing 101 and the inner casing 102 are rotated together by the driving force of a drive unit (not shown), and a differential speed is applied by a differential speed device 104. As a result, the outer casing 101 and the inner casing 102 rotate at different rotational speeds.

[0028] The rotational speed of the inner cylinder 102 is approximately 3 to 5 rpm higher than the rotational speed of the outer cylinder 101. As a result, the inner cylinder 102 (screw) rotates relatively faster than the outer cylinder 101 (cylindrical body), and within the outer cylinder 101, the solid-liquid mixture and solid components are gradually transported downstream (to the right in Figure 1) by the inner cylinder 102. The rotational speed of the outer cylinder 101 is set appropriately considering the properties of the material to be centrifuged and the requirements from downstream processes, but it can be, for example, 1500 to 3600 rpm. The rotational speed of the inner cylinder 102 is set to a value approximately 3 to 5 rpm higher than the rotational speed of the outer cylinder 101.

[0029] Furthermore, in the downstream end region of the inner cylinder 102, the diameter of the shaft 102a is gradually increased from the upstream side to the downstream side, thereby gradually reducing the space formed between the outer cylinder 101 and the shaft 102a. As a result, in this end region, the solid components are compressed between the shaft 102a and the inner wall of the outer cylinder 101, forming a dewatered cake. This dewatered cake is discharged from the downstream end of the centrifugal dewaterer 100. On the other hand, the liquid components after solid-liquid separation are discharged from the upstream end of the centrifugal dewaterer 100. Hereafter, the side to which the solid-liquid mixture is supplied (left side in Figure 1) will be referred to as the "supply side," and the side from which the dewatered cake is discharged (right side in Figure 1) will be referred to as the "discharge side." The supply side and the discharge side are at opposite ends in the extending direction of the centrifuge 100.

[0030] [Configuration of the diagnostic device] Next, the configuration of the diagnostic device 1 according to this embodiment will be described. The diagnostic device 1 according to this embodiment includes a vibration sensor 2, an outer casing tachometer 3, an inner casing tachometer 4, and a computer 5 (an example of a computing device) (Figure 2). One vibration sensor 2 is provided in each of the two bearing sections 103a and 103b. When distinguishing between them, the one provided in the supply-side bearing section 103a is referred to as vibration sensor 2a, and the one provided in the discharge-side bearing section 103b is referred to as vibration sensor 2b.

[0031] As the vibration sensor 2, a known sensor capable of converting vibration into an electrical signal can be used. Examples of usable sensors include acceleration sensors, velocity sensors, and non-contact displacement sensors. While it is not prohibited for the two vibration sensors 2a and 2b to be of different types, it is preferable for the two vibration sensors 2a and 2b to be of the same type from the viewpoint of simplifying the procurement of materials and calculation processing. In the following explanation, the case in which both vibration sensors 2a and 2b are acceleration sensors will be described as an example, but the diagnostic device 1 according to this embodiment will be similarly established even when other types of vibration sensors are used.

[0032] The vibration sensor 2 is electrically connected to the computer 5 and is configured to input measured values ​​to the computer 5. The vibration sensor 2 may input the measured physical quantity itself to the computer 5, or it may input a value that has undergone some processing to the computer 5.

[0033] As an example of a configuration that enables such processing, the vibration sensor 2 may have a filter circuit. In this case, the measured values ​​output from the vibration sensor 2 become extracted data obtained by extracting a specific frequency range determined according to the characteristics of the filter circuit from the measured values ​​themselves that are caused by vibrations of the centrifugal dehydrator 100. Preferably, the characteristics of the filter circuit are determined by considering the rotation speed of the outer drum 101 and the rotation speed of the inner drum 102.

[0034] The outer drum tachometer 3 is a tachometer that measures the rotational speed of the outer drum 101, and any known tachometer can be used. If the centrifugal dehydrator 100 is equipped with a tachometer that measures the rotational speed of the outer drum 101, instead of providing the outer drum tachometer 3 to the diagnostic device 1, a signal line may be connected so that the output value of the tachometer already equipped in the centrifugal dehydrator 100 is input to the computer 5.

[0035] The inner drum tachometer 4 is a tachometer that measures the rotational speed of the inner drum 102, and any known tachometer can be used. The measurement methods of the outer drum tachometer 3 and the inner drum tachometer 4 may be the same or different. If the centrifugal dewatering machine 100 is equipped with a tachometer that measures the rotational speed of the inner drum 102, similar to the outer drum tachometer 3, this may be used instead of the inner drum tachometer 4.

[0036] Computer 5 is a terminal equipped with an arithmetic unit 51, a storage device 52, an input terminal 53, a display 54, and an input device 55. Computer 5 may be a dedicated terminal with a configuration known in the technical field of diagnostic devices, measuring devices, etc., or it may be a general-purpose information terminal such as a personal computer, tablet terminal, or smartphone.

[0037] The arithmetic unit 51 is configured 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 computer 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 sensor 2 (2a, 2b), the outer casing tachometer 3, and the inner casing tachometer 4, and vibration waveform data is input to the computer 5 through the input terminal 53. The input signals from the vibration sensor 2, the outer casing tachometer 3, and the inner casing tachometer 4 input to the input terminal 53 are synchronized.

[0038] The display 54 and input device 55 are components that function as the user interface of the computer 5. The display 54 is provided for the purpose of displaying various data handled by the computer 5 and presenting (outputting) information to the user, and is implemented as a well-known liquid crystal display or the like. The input device 55 is provided for the purpose of receiving various input operations from the user to the computer 5, and is implemented as a keyboard, mouse, buttons, touch panel, or the like.

[0039] [Structure of the diagnostic method] Next, the configuration of the diagnostic method according to this embodiment will be described. The diagnostic method according to this embodiment includes an acquisition step S10, a beat analysis step S20, and a diagnostic step S30 (Figure 3). The diagnostic method according to this embodiment is performed using the diagnostic device 1, and each function of the diagnostic program according to this embodiment is executed in each step. Therefore, the main entity that executes the acquisition step S10, the beat analysis step S20, and the diagnostic step S30 is the computer 5 (particularly the arithmetic unit 51) of the diagnostic device 1.

[0040] In the following explanation, we will use the example of a case where the rotation speed of the outer drum 101 is 3600 rpm and the rotation speed of the inner drum 102 is 3603 rpm. In the explanation, we may use statements to the effect that the rotation speed of the centrifugal dehydrator 100 is approximately 3600 rpm.

[0041] (1) Acquisition process S10 The acquisition process S10 is a process in which vibration waveform data caused by vibrations of the centrifugal dehydrator 100, the rotation speed of the outer drum 101, and the rotation speed of the inner drum 102 are acquired (by the computer 5). Specifically, the measured values ​​measured by the vibration sensors 2 (2a, 2b), the outer drum tachometer 3, and the inner drum tachometer 4 are input to the computer 5.

[0042] (2) Beat analysis process S20 The beat analysis step S20 is a step in which the beat waveform of the centrifugal dehydrator 100 is identified based on the detection values ​​of the two vibration sensors 2.

[0043] A humming noise occurs during the operation of the centrifugal dewatering machine 100 due to the difference in rotational speed between the outer drum 101 and the inner drum 102. The humming period, which is the period of this humming, is determined by dividing 60 seconds by the difference in rotational speed between the outer drum 101 and the inner drum 102, and is approximately 12 to 20 seconds. As a result, the intensity of the vibration of the centrifugal dewatering machine 100 changes periodically with a period of approximately 12 to 20 seconds. As explained above, if the rotational speed of the outer drum 101 is 3600 rpm and the rotational speed of the inner drum 102 is 3603 rpm, then the difference in rotational speed between the outer drum 101 and the inner drum 102 is 3 rpm, and the humming period can be theoretically derived to be 20 seconds.

[0044] In the beat analysis step S20 of this embodiment, the envelope of the vibration waveform data (a plot with time on the horizontal axis and the measured value of the vibration sensor 2 on the vertical axis) is identified (S21), and feature values ​​are extracted from the envelope (S22). In this embodiment, the identification of the envelope (S21) and the extraction of feature values ​​(S22) are performed for each measured value of the vibration sensor 2a (supply side) and the vibration sensor 2b (discharge side).

[0045] Corresponding to the rotational speed of the centrifugal dehydrator 100 being approximately 3600 rpm, the centrifugal dehydrator 100 vibrates with a period of approximately 17 milliseconds (60 seconds ÷ 3600 ≈ 0.017 seconds). The envelope of the vibration waveform data is identified by performing a Hilbert transform on the vibration waveform data that vibrates with a period of approximately 17 milliseconds, or by sequentially connecting the points where the absolute value takes its maximum in each period (Figure 4).

[0046] The vibration waveform data acquired in acquisition step S10 contains components such as noise in addition to components caused by the vibration of the centrifugal dehydrator 100. Therefore, filtering may be performed to extract data within a predetermined frequency range, including the rotational frequency (approximately 60 Hz) determined based on the rotational speed of the outer drum 101 and the rotational speed of the inner drum 102 (rotational speed of the centrifugal dehydrator 100: approximately 3600 rpm), from the vibration waveform data. The filtering may be a bandpass filter. In this case, the envelope is identified using the extracted data obtained by the filtering process.

[0047] Furthermore, if the vibration sensor 2 has a filter circuit and filtered extracted data is input from the vibration sensor 2 to the computer 5, envelope processing is performed on the extracted data. In other words, the extraction of extracted data may be performed hardware-wise in the vibration sensor 2, or software-wise in the computer 5.

[0048] Next, based on the identified envelope, various feature values ​​are extracted to be used in the calculation process in diagnostic step S30. First, the beat period is extracted. The envelope shows a waveform that oscillates with 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.

[0049] (3) Diagnostic process The diagnostic step S30 is a step in which residual unbalance of the centrifugal dehydrator 100 is identified based on the envelope and characteristic values ​​of the envelope identified in the beat analysis step S20. The procedure broadly includes identifying the amplitude (S31), identifying the phase difference (S32), and applying a mechanical model (S33).

[0050] (3-1) Amplitude identification As described above, the humming of the centrifugal dehydrator 100 is caused by the difference in rotational speed between the outer drum 101 and the inner drum 102. This phenomenon can be explained by the fact that when the phases of the residual unbalance of the outer drum 101 and the residual unbalance of the inner drum 102 are close, the vibrations caused by both act additively and become larger, and when the phases are far apart, the vibrations caused by both act in a way that cancels each other out and becomes smaller. Therefore, in the envelope identified in the humming analysis process S20, the point where the amplitude takes its maximum value V1 is the point where the phases of the residual unbalance of the outer drum 101 and the residual unbalance of the inner drum 102 coincide, and the point where the amplitude takes its minimum value V2 is the point where the phase difference is 180°.

[0051] Here, the amplitude a of the component caused by the residual unbalance of the outer shell 101 B , angular velocity ω Band for the components caused by the residual imbalance of the inner cylinder 102, the amplitude a S , the angular velocity ω S Then, the acceleration A detected by the vibration sensor 2 is expressed by the following formula (1) as a function of time t.

Equation

[0052] The envelope line specified in the beat analysis step S20 is obtained by connecting in order the points where the absolute value takes the maximum value in each period of the waveform represented by formula (1). Therefore, the maximum value V1 and the minimum value V2 of the amplitude of the envelope line are represented by the following formula (2) and formula (3), respectively.

Equation

[0053] Formula (3) is classified as follows according to the magnitude relationship between a B and a S .

Equation

[0054] Therefore, when a B > a S , from the simultaneous equations of formula (2) and formula (3-1), a B and a S are specified as follows.

Equation

[0055] Similarly, when a B < a S , from the simultaneous equations of formula (2) and formula (3-1), a B and a S are specified as follows.

Equation

[0056] That is, a B and a S If we can determine the relative magnitudes of these, then based on the maximum amplitudes V1 and V2 extracted from the envelope, a B and a S It is possible to determine this. However, from the envelope itself, a B and a S Since the relative size relationship cannot be determined, a process is needed to determine it.

[0057] 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 Virtual waveform A i Create the following. Note that the minimum value V2 of the envelope is extracted from the envelope, and the angular velocity ω B Since this can be determined from the rotational speed of the outer casing 101, all of them can be determined. The rotational speed of the outer casing 101 used at this time may be the actual value measured by the outer casing tachometer 3, or a rough value based on the operating conditions (3600 rpm in this embodiment) may be used. In any case, from the information available at this point, the virtual waveform A can be determined. i It is possible to create this. Below, we will explain the case using the measured value of the rotational speed of the outer casing 101. Virtual waveform A i This can be expressed by the following equation (6).

number

[0058] Next, the acceleration A detected by the vibration sensor 2 and the virtual waveform A i The waveform obtained by adding the two is calculated. This added waveform is represented by the following equation (7).

number

[0059] Now, substitute equation (3) into equation (7).

number

[0060] a B >a S In this case, V2 = a B -a S Since (Equation (3-1)) is true, Equation (8) can be transformed as follows.

number

[0061] Considering the case where the amplitude of the envelope takes its minimum value V2, at this time the component due to the residual unbalance of the outer shell 101 and the component due to the residual unbalance of the inner shell 102 are in opposite phase, so sin(ω B t) = -sin(ω S t) Therefore, equation (8-1) can be further transformed as follows.

number

[0062] The right-hand side of equation (8-2) is nothing more than twice the acceleration A (equation (1)) detected by the vibration sensor 2. Therefore, a B >a S In this case, the acceleration A corresponds to the virtual waveform A. i By performing the addition process, the minimum value V2 of the envelope is doubled. Furthermore, if a rough value is used for the rotation speed of the outer shell 101, the minimum value V2 of the envelope is approximately doubled.

[0063] on the other hand, a B S In this case, V2 = a S -a B Since (Equation (3-2)) is true, Equation (8) can be transformed as follows.

number

[0064] a B >a S Similar to the case where the amplitude of the envelope takes its minimum value V2, sin(ω B t) = -sin(ω​S Using t), equation (8-3) can be further transformed as follows:

number

[0065] From equation (8-4), a B S In this case, the acceleration A corresponds to the virtual waveform A. i By performing the addition process, the minimum value V2 of the envelope becomes 0. Furthermore, when a rough value is used for the rotation speed of the outer shell 101, the minimum value V2 of the envelope becomes approximately 0.

[0066] To summarize the above process, for the identified envelope, the minimum amplitude V2 extracted from the envelope and the angular velocity ω determined from the rotational speed of the outer shell 101 are used. B Virtual waveform A created from i When added, the minimum amplitude of the added waveform is either twice the minimum value V2 of the original envelope, or zero. Based on this difference in behavior, a B and a S The relationship between the two can be determined. That is, when the minimum value of the summation waveform becomes twice the minimum value V2 of the original envelope, a B >a S And when the minimum value of the amplitude of the summation waveform becomes 0, a B S That is the case.

[0067] Thus, virtual waveform A i Using a B and a S Since the relationship between them can be determined, we can use equations (4-1) and (5-1), or equations (4-2) and (5-2), to determine a B and a S It can be identified.

[0068] Note that the above refers to virtual waveform A i The angular velocity of ω B However, instead of this, virtual waveform A i The angular velocity of ω S ​​This is also acceptable. In this case as well, the angular velocity ω S You may use measured values ​​or approximate values. In this case, however, contrary to the above case, a B >a S When this happens, equation (8-4) holds true, and a B S Equation (8-2) holds true in this case.

[0069] The above process is performed on each envelope identified from the measured values ​​of vibration sensor 2a (supply side) and vibration sensor 2b (discharge side). This determines the amplitude a of the component of the acceleration on the supply side that is due to the residual unbalance of the outer shell 101. Bk , the amplitude a of the component of the acceleration on the discharge side that is 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 unbalance of the inner drum 102 Sk , and the amplitude a of the component of the acceleration on the discharge side due to the residual unbalance of the inner drum 102 Sh , is identified.

[0070] (3-2) Identification of Phase Difference Using the four amplitudes identified above, the sensor-directional components of acceleration can be expressed as follows: the supply-side acceleration A1 and discharge-side acceleration A2 due to residual unbalance in the outer casing 101, and the supply-side acceleration A3 and discharge-side acceleration A4 due to residual unbalance in the inner casing 102, respectively. Note that Δφ is the phase difference between the supply-side and discharge-side acceleration due to residual unbalance in the outer casing 101, and Δξ is the phase difference between the supply-side and discharge-side acceleration due to residual unbalance in the inner casing 102.

number

[0071] In addition, the acceleration A detected by the vibration sensor 2a on the supply side k and acceleration A detected by the discharge-side vibration sensor 2b h These are expressed as follows: Acceleration A k , A h ​This is measured by vibration sensors 2a and 2b. Note that acceleration A k is, amplitude a k The acceleration of the wave is measured by the vibration sensor 2a, and acceleration A h is, amplitude a h This is the acceleration measured by vibration sensor 2b for the wave.

number

[0072] Acceleration A k Considering the moment when it is at its maximum, this corresponds to the moment when the component due to the residual unbalance of the outer casing 101 and the component due to the residual unbalance of the inner casing 102 are in phase on the supply side and reach the sensor mounting position. That is, at this time, sin(ω B t) = sin(ω S t)=1. At this time, the acceleration and phase of the outer and inner drums on the supply and discharge sides are as follows: The relationship is schematically illustrated in Figure 5. In the figure, Δθ represents the phase difference between the acceleration of the outer and inner drums on the discharge side, and is determined as the phase difference of the envelopes identified from the respective measurements of vibration sensors 2a and 2b.

[0073] Acceleration a on the discharge side h And the acceleration a h Acceleration a is a component resulting from the residual unbalance of the inner drum 101. Bh The phase difference with Δθ B Therefore, the following equation holds true.

number

[0074] From equations (10-1) and (10-2), the following equation (11) is derived.

number

[0075] Also, acceleration A k and acceleration Ah The phase difference Δθ with D is obtained. The acceleration A k of the waveform of B is defined as the period t k of the acceleration A waveform, and the difference between the time when the acceleration at the sensor position is maximum and the time when the acceleration at the sensor position is maximum in the acceleration A waveform is defined as Δt. Then, Δθ h is given by the following equation (12). D

Equation

[0076] The phase difference Δφ between the supply side and the discharge side of the acceleration caused by the residual imbalance of the outer cylinder 101, and the phase difference Δξ between the supply side and the discharge side of the acceleration caused by the residual imbalance of the inner cylinder 102 are given by the following equations, respectively.

Equation

[0077] (3-3) Application of the mechanical model [[ID=三十四]] In the diagnosis step S30, a mechanical model (Figure 6) is assumed in which there is one load on each of the supply side and the discharge side of the outer cylinder 101 and the inner cylinder 102, and the masses of the four loads in the mechanical model are specified. That is, instead of specifying the position and magnitude of the factors of the residual imbalance that actually exist (such as adhesion and damage), the residual imbalance of the centrifugal dehydrator 100 is specified as a model represented by four loads.

[0078] In the mechanical model (Figure 6), a load 61 placed on the supply side of the outer cylinder 101, a load 62 placed on the discharge side, a load 63 placed on the supply side of the inner cylinder 102, and a load 64 placed on the discharge side are set. Each parameter of the loads 61 to 六十四 is represented by the symbols shown in the following table. However, the masses m B1 、m B2 、m S1 、m S2 ​Other parameters are constants predetermined when setting up the dynamic model. Also, the mass on the supply side of the centrifugal dewatering machine 100 is M. k Let M be the mass of the discharge side. h Let the total length be L0.

[0079] Table 1: Symbols representing each parameter of load in the mechanical model [Table 1]

[0080] Solving this dynamic model, assuming equilibrium of excitation forces, yields the following solution.

number

[0081] In other words, the acceleration A detected by the vibration sensors 2 (2a, 2b) k , A h And the angular velocity ω is calculated from the rotational speed detected by the outer casing tachometer 3. B The angular velocity ω is calculated from the rotational speed detected by the internal drum tachometer 4. S Using and , the amplitude a of the component of the acceleration on the supply side caused by the residual unbalance of the outer shell 101 Bk , the amplitude a of the component of the acceleration on the discharge side that is 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 unbalance of the inner drum 102 Sk , and the amplitude a of the component of the acceleration on the discharge side due to the residual unbalance of the inner drum 102 Sh Furthermore, by identifying the phase difference Δφ between the supply side and discharge side of acceleration due to residual unbalance in the outer shell 101 and the phase difference Δξ between the supply side and discharge side of acceleration due to residual unbalance in the inner shell 102, and substituting these into equations (15-1) to (15-4), the mass m of loads 61 to 64 is obtained. B1 , m B2 , m S1 , m S2 The mass m of the load 61-64 determined at this time can be determined. B1 , m B2 , m S1 , mS2 This can be said to represent the residual imbalance that actually exists in the centrifugal dehydrator 100.

[0082] Determined mass m B1 , m B2 , m S1 , m S2 From this, the relative magnitudes of residual unbalance in the four regions divided into the supply side and discharge side of the outer drum 101 and inner drum 102, as well as the overall degree of residual unbalance of the centrifugal dewatering machine 100, can be estimated. For example, among the four masses, mass m B1 If it is larger than the others, it is presumed that there is a significant cause of residual unbalance in the supply-side region of the outer shell 101 compared to other regions. Also, mass m B1 , m B2 , m S1 , m S2 By regularly identifying the cause and monitoring its trends, changes in the residual unbalance of the centrifugal dewatering machine 100 can be identified. This allows for the estimation of the residual unbalance without disassembling the centrifugal dewatering machine 100, enabling timely maintenance.

[0083] [Other Embodiments] Finally, other embodiments of the diagnostic device, diagnostic method, and diagnostic program according to the present invention will be described. Note that the configurations disclosed in each of the following embodiments can be applied in combination with configurations disclosed in other embodiments, provided that this does not create a conflict.

[0084] In the above embodiment, a configuration in which four loads 61 to 64 are set in the mechanical model (Figure 6) was described as an example. However, when using a mechanical model in the present invention, the number of loads that can be set is not limited.

[0085] In the above embodiment, a configuration in which the diagnostic device 1 includes an outer drum tachometer 3 and an inner drum tachometer 4 was described as an example. However, as stated above, in the diagnostic device, diagnostic method, and diagnostic program according to the present invention, it is also possible to use an approximate value instead of the actual measured value of the rotational speed, so one or both of the outer drum tachometer and the inner drum tachometer may be omitted.

[0086] In the above embodiment, a configuration in which the envelope is identified at the beginning of a series of analyses was described as an example. However, the detector of the vibration sensor may be analyzed directly without identifying the envelope. However, from the viewpoint of reducing the amount of computational processing required for the analysis, it is preferable to identify the envelope.

[0087] In the above embodiment, a configuration was described as one in which the phase difference Δφ between the supply side and discharge side of acceleration due to residual unbalance in the outer drum 101, and the phase difference Δξ between the supply side and discharge side of acceleration due to residual unbalance in the inner drum 102 are identified. However, even if the identification of the phase difference is omitted, the residual unbalance of the centrifugal dewatering machine can be identified at a level sufficient for practical use, although the accuracy may be lower compared to the above embodiment.

[0088] In the above embodiment, a configuration in which the residual unbalance of the outer drum 101 and the residual unbalance of the inner drum 102 are separated was described as an example. However, this separation may be omitted, and the residual unbalance may be identified as the overall residual unbalance of the centrifugal dewatering machine 100.

[0089] With regard to other configurations, the embodiments disclosed herein are illustrative in all respects, and it should be understood that the scope of the present invention is not limited thereto. Those skilled in the art will readily understand that modifications can be made as appropriate without departing from the spirit of the invention. Therefore, other embodiments modified without departing from the spirit of the invention are naturally included within the scope of the present invention. [Industrial applicability]

[0090] This invention can be used, for example, in diagnosing centrifugal dehydrators. [Explanation of Symbols]

[0091] 1: Diagnostic device 2: Vibration sensor 3: Outer casing tachometer 4: Inner drum tachometer 5: Computer 51: Arithmetic device 52: Storage device 53: Input terminals 54: Display 55: Input Devices 100: Centrifugal dehydrator 101: Outer shell 102: Inner torso 102a: Axis 103: Bearing part 104: Differential speed device A: Acceleration

Claims

1. A diagnostic device for diagnosing a centrifugal dewatering machine comprising an outer and inner drum arranged concentrically, supported by two bearings located at both ends in the extending direction, and rotating at different rotational speeds, The system comprises vibration sensors provided at least one on each of the two bearing sections, and a computing device. The aforementioned computing device Based on the detection values ​​of the two vibration sensors, the waveform of the humming of the centrifugal dehydrator to be diagnosed is identified, and, A diagnostic device that identifies residual imbalance in the centrifugal dehydrator based on the aforementioned humming waveform.

2. The diagnostic device according to claim 1, wherein the calculation device uses the detected values ​​of the two vibration sensors to solve a mechanical model of a centrifugal dehydrator in which residual unbalance is set at a predetermined position, and obtains a solution in which the residual unbalance in the mechanical model represents the actual residual unbalance, thereby identifying the residual unbalance of the centrifugal dehydrator to be diagnosed.

3. The diagnostic device according to claim 1, wherein the calculation device separates the residual unbalance of the centrifugal dehydrator to be diagnosed into residual unbalance of the outer drum of the centrifugal dehydrator and residual unbalance of the inner drum of the centrifugal dehydrator.

4. The diagnostic device according to claim 1, wherein the calculation device identifies the phase difference between residual unbalance located at one end of the centrifugal dehydrator in the extending direction and residual unbalance located at the other end of the extending direction.

5. The diagnostic device according to claim 1, wherein the calculation device further identifies the envelope of the hum waveform of the centrifugal dehydrator to be diagnosed.

6. The calculation device generates a virtual waveform in which the angular velocity is the same as the angular velocity of the outer shell or the inner shell, and the amplitude is greater than 0 and less than or equal to the minimum amplitude of the envelope. The virtual waveform and the envelope are added together to generate an added waveform, and, The diagnostic device according to claim 5, which, based on the summation waveform, separates the residual unbalance of the centrifugal dehydrator to be diagnosed into residual unbalance of the outer drum of the centrifugal dehydrator and residual unbalance of the inner drum of the centrifugal dehydrator.

7. The system further comprises an outer drum tachometer for measuring the rotational speed of the outer drum of the centrifugal dehydrator to be diagnosed, and an inner drum tachometer for measuring the rotational speed of the inner drum of the centrifugal dehydrator, The diagnostic device according to any one of claims 1 to 6, wherein the calculation device identifies the residual unbalance of the centrifugal dehydrator to be diagnosed based on the waveform of the hum, the rotation speed of the outer drum, and the rotation speed of the inner drum.

8. A diagnostic method for diagnosing a centrifugal dewatering machine comprising an outer and inner drum arranged concentrically, supported by two bearings located at both ends in the extending direction, and rotating at different rotational speeds, A step of identifying the humming waveform of the centrifugal dehydrator to be diagnosed based on the detection value of vibration sensors provided at least one on each of the two bearing parts, A diagnostic method comprising the step of identifying residual unbalance in the centrifugal dehydrator based on the waveform of the aforementioned hum.

9. A diagnostic program for diagnosing a centrifugal dewatering machine comprising an outer and inner drum arranged concentrically, supported by two bearings located at both ends in the extending direction, and rotating at different rotational speeds from each other, When executed by a computer, A function to identify the humming waveform of the centrifugal dehydrator to be diagnosed based on the detection value of vibration sensors provided at least one on each of the two bearing parts, A diagnostic program that enables a function to identify residual imbalance in the centrifugal dehydrator based on the aforementioned humming waveform.

Images