Diagnostic device, diagnostic method, and diagnostic program

Abstract

To make it possible to accurately diagnose the condition of a vibrating tube of a Coriolis mass flowmeter.SOLUTION: A diagnostic device (2) includes: a stiffness damping diagnostic unit (61) that generates stiffness damping diagnostic results regarding changes in stiffness of a vibrating tube (11) by applying a driving force with an oscillation feedback gain made constant to the vibrating tube (11) in a Coriolis mass flowmeter (1) that measures the flow rate and density of fluid flowing through the vibrating tube (11) based on Coriolis force acting on the vibrating tube (11) that is vibrated; and a wall thickness diagnostic unit (70) that executes calculations regarding the wall thickness of the vibrating tube (11) based on the stiffness damping diagnostic results and generates wall thickness diagnostic results regarding changes in the wall thickness of the vibrating tube (11).SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] Coriolis mass flowmeters are known as one type of flowmeter used in plants. Coriolis mass flowmeters vibrate a vibrating tube (U-shaped tube) through which a fluid flows by exciting a coil, and measure the Coriolis force generated by the fluid passing inside the vibrating tube through the twisting of the vibrating tube. Since the Coriolis force increases according to the flow rate of the fluid, it is possible to measure the flow rate through the width and phase of the twisting of the vibrating tube.

[0003] In Coriolis mass flowmeters, the flow rate is measured by using the twisting of the vibrating tube, so if the vibrating tube becomes corroded, it will cause errors in the flow rate measurement. It is also desirable to know the corrosion of the vibrating tube for the maintenance of the tube. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4952820 [Patent Document 2] Patent No. 4469337 [Patent Document 3] Patent No. 4866423 [Patent Document 4] Patent No. 3523592 [Patent Document 5] Patent No. 7024466 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned conventional techniques have room for improvement in terms of accurately diagnosing the condition of the vibrating tube of a Coriolis mass flowmeter. For example, in Patent Document 1, amplitude information is used to determine corrosion of the vibrating tube, which is affected by the amplification sensitivity of the driving circuit and the measurement circuit. In addition, in Patent Document 1, corrosion of the vibrating tube is determined based on rigidity, and the change in wall thickness is not directly obtained.

[0006] The present invention has been made in view of the above, and an object of the present invention is to accurately diagnose the condition of a vibrating tube of a Coriolis mass flowmeter. [Means for solving the problem]

[0007] The present invention provides a diagnostic device comprising a Coriolis mass flowmeter that measures the flow rate and density of a fluid flowing through a vibrating tube based on the Coriolis force acting on the vibrating tube, the diagnostic device including: a stiffness damping diagnostic unit that applies a driving force with a constant oscillation feedback gain to the vibrating tube to generate a stiffness damping diagnostic result related to a change in stiffness of the vibrating tube; and a wall thickness diagnostic unit that performs a calculation related to the thickness of the vibrating tube based on the stiffness damping diagnostic result to generate a wall thickness diagnostic result related to a change in the wall thickness of the vibrating tube.

[0008] The present invention also provides a diagnostic method in which a computer executes processing in a Coriolis mass flowmeter that measures the flow rate and density of a fluid flowing through a vibrating tube based on the Coriolis force acting on the vibrating tube, applies a driving force with a constant oscillation feedback gain to the vibrating tube, generates a stiffness damping diagnostic result related to a stiffness change in the vibrating tube, performs calculations related to the thickness of the vibrating tube based on the stiffness damping diagnostic result, and generates a thickness diagnostic result related to the thickness change of the vibrating tube.

[0009] The present invention also provides a diagnostic program that causes a computer to execute a process in which a Coriolis mass flowmeter that measures the flow rate and density of a fluid flowing through a vibrating tube based on the Coriolis force acting on the vibrating tube applies a driving force with a constant oscillation feedback gain to the vibrating tube to generate a stiffness damping diagnostic result related to a stiffness change in the vibrating tube, performs a calculation related to the thickness of the vibrating tube based on the stiffness damping diagnostic result, and generates a thickness diagnostic result related to the thickness change of the vibrating tube. Effect of the Invention

[0010] According to the present invention, it is possible to accurately diagnose the condition of the vibrating tube of a Coriolis mass flowmeter. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a diagnostic system according to an embodiment. [Diagram 2] 1 is a block diagram showing an example of the configuration of a Coriolis mass flowmeter according to an embodiment; [Diagram 3] FIG. 4 is a diagram illustrating an example of a measurement process of the Coriolis mass flowmeter according to the embodiment. [Figure 4] FIG. 2 is a block diagram showing an example of the configuration of each device of the diagnostic system according to the embodiment. [Diagram 5] FIG. 11 is a diagram showing an example of the overall stiffness decay diagnosis process according to the embodiment; [Figure 6] FIG. 11 is a diagram showing an example of the overall stiffness decay diagnosis process according to the embodiment; [Figure 7] FIG. 2 is a diagram showing an example of stiffness attenuation diagnosis processing 1 according to the embodiment. [Figure 8] FIG. 11 is a diagram showing an example of stiffness attenuation diagnosis processing 2-1 according to the embodiment. [Figure 9] FIG. 11 is a diagram showing an example of stiffness attenuation diagnosis processing 2-2 according to the embodiment. [Figure 10] FIG. 11 is a diagram showing an example of stiffness attenuation diagnosis processing 3 according to the embodiment. [Figure 11] FIG. 11 is a diagram showing an example of stiffness attenuation diagnosis processing 4 according to the embodiment. [Figure 12] FIG. 11 is a diagram showing an example of an entire thickness diagnosis process according to the embodiment; [Figure 13] FIG. 2 is a diagram showing an example of a wall thickness diagnosis process 1 according to the embodiment. [Figure 14] FIG. 4 is a diagram showing an example of a wall thickness diagnosis process 2 according to the embodiment. [Figure 15] 11 is a diagram showing an example of a wall thickness diagnosis process 3 according to the embodiment. FIG. [Figure 16] FIG. 4 is a diagram showing an example of a wall thickness diagnosis process 4 according to the embodiment. [Figure 17] FIG. 4 is a diagram showing an example of a wall thickness diagnosis process 5 according to the embodiment. [Figure 18] FIG. 11 is a diagram showing an example of the entire density error diagnosis and simple correction process according to the embodiment. [Figure 19] FIG. 2 is a diagram showing an example of density error diagnosis and simple correction processing 1 according to the embodiment. [Figure 20] FIG. 11 is a diagram showing an example of density error diagnosis and simple correction processing 2 according to the embodiment. [Figure 21] FIG. 11 is a diagram showing an example of density error diagnosis and simple correction processing 3 according to the embodiment. [Figure 22] FIG. 11 is a diagram showing an example of density error diagnosis and simple correction processing 4 according to the embodiment. [Figure 23] FIG. 11 is a diagram showing an example of the entire flow rate error diagnosis and simple correction process according to the embodiment. [Figure 24] FIG. 4 is a diagram showing an example of flow rate error diagnosis and simple correction processing 1 according to the embodiment. [Diagram 25] FIG. 11 is a diagram showing an example of flow rate error diagnosis and simple correction processing 2 according to the embodiment. [Figure 26] FIG. 11 is a diagram showing an example of flow rate error diagnosis and simple correction processing 3 according to the embodiment. [Figure 27] FIG. 11 is a diagram showing an example of flow rate error diagnosis and simple correction processing 4 according to the embodiment. [Figure 28] FIG. 4 is a diagram showing an example of an entire timing prediction diagnosis process according to the embodiment; [Figure 29]FIG. 2 is a diagram showing an example of a timing prediction diagnosis process 1 according to the embodiment. [Diagram 30] FIG. 4 is a diagram showing an example of a timing prediction diagnosis process 2 according to the embodiment. [Diagram 31] FIG. 11 is a diagram showing an example of a timing prediction diagnosis process 3 according to the embodiment. [Diagram 32] FIG. 4 is a diagram showing an example of a timing prediction diagnosis process 4 according to the embodiment. [Diagram 33] FIG. 2 is a diagram showing an example of a wall thickness diagnosis result 1 according to the embodiment. [Diagram 34] FIG. 11 is a diagram showing an example of a wall thickness diagnosis result 2 according to the embodiment. [Diagram 35] FIG. 11 is a diagram showing an example of a density diagnosis result according to the embodiment. [Diagram 36] FIG. 4 is a diagram showing an example of a flow rate diagnosis result 1 according to the embodiment. [Figure 37] FIG. 2 is a diagram showing an example of a flow rate diagnosis result 2-1 according to the embodiment. [Figure 38] FIG. 11 is a diagram showing an example of a flow rate diagnosis result 2-2 according to the embodiment. [Figure 39] FIG. 11 is a diagram showing an example of a flow rate diagnosis result 2-3 according to the embodiment. [Diagram 40] FIG. 11 is a diagram showing an example of a timing prediction diagnosis result according to the embodiment. [Diagram 41] 10 is a flowchart showing an example of the overall flow of diagnostic processing according to the embodiment. [Diagram 42] 5 is a flowchart showing an example of the overall flow of stiffness attenuation diagnosis processing according to the embodiment. [Diagram 43] 10 is a flowchart showing an example of a flow of a stiffness attenuation diagnosis process according to the embodiment. [Diagram 44] 10 is a flowchart showing an example of the overall flow of a wall thickness diagnosis process according to the embodiment. [Diagram 45] 1 is a flowchart showing an example of the overall flow of density diagnosis and simple correction processing according to the embodiment. [Figure 46] 5 is a flowchart showing an example of the overall flow rate diagnosis and simple correction process according to the embodiment. [Figure 47]5 is a flowchart showing an example of the overall flow of a timing prediction diagnosis process according to the embodiment. [Figure 48] FIG. 2 is a diagram illustrating an example of a hardware configuration according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A diagnostic device, a diagnostic method, and a diagnostic program according to an embodiment of the present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the embodiment described below.

[0013] [Embodiment] The configuration of the diagnostic system (1000) according to this embodiment, the configuration of the Coriolis mass flowmeter (1), the configuration of each device in the diagnostic system (1000), details of each process of the diagnostic device (2), the results of each process, and the flow of each process will be described below in order, and finally the effects of this embodiment will be described.

[0014] 1. Configuration of diagnostic system (1000) The configuration of the diagnostic system (1000) according to this embodiment will be described in detail with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of the diagnostic system (1000) according to the embodiment. Below, an example of the overall configuration of the diagnostic system (1000), the processing of the diagnostic system (1000), the basic operation of the Coriolis mass flowmeter (1), and problems with the conventional technology will be described in this order, and finally, the effects of the diagnostic system (1000) will be described.

[0015] (1-1. Example of the overall configuration of the diagnostic system (1000)) The diagnostic system (1000) includes a Coriolis mass flowmeter (1), a diagnostic device (2), and a calibration device (3). The Coriolis mass flowmeter (1), the diagnostic device (2), and the calibration device (3) are connected to each other via a predetermined communication network (not shown) so as to be able to communicate with each other by wire or wirelessly. The diagnostic system (1000) shown in FIG. 1 may include a plurality of Coriolis mass flowmeters (1), a plurality of diagnostic devices (2), and a plurality of calibration devices (3). As will be described later with reference to FIG. 2, the Coriolis mass flowmeter (1) may have at least one of the diagnostic device (2) and the calibration device (3) as an internal device. The diagnostic device (2) and the calibration device (3) may be integrated into an external device (31).

[0016] (1-2. Overall processing of diagnostic system (1000)) The overall processing of the above-mentioned diagnostic system (1000) will be described. First, the diagnostic device (2) acquires the measured value measured by the Coriolis mass flowmeter (1) (step S1). Next, the diagnostic device (2) executes the stiffness damping diagnostic processing (step S2), the wall thickness diagnostic processing (step S3), the density error diagnosis and simple correction processing (step S4), the flow rate error diagnosis and simple correction processing (step S5), and the timing prediction diagnostic processing (step S6) in order. Then, the diagnostic device (2) transmits the diagnosis result of the above steps S2 to S6 to the Coriolis mass flowmeter (1) (step S7). In addition, the diagnostic device (2) transmits the calibration timing of the Coriolis mass flowmeter (1), which is the timing prediction diagnosis result of the above step S6, to the calibration device (3) (step S8). Note that the above steps S1 to S8 can be executed in a different order. Also, among the above steps S1 to S8, some processing may be omitted.

[0017] (1-3. Basic operation of Coriolis mass flowmeter (1)) 2-3 and equations, a basic operation of the Coriolis mass flowmeter 1 in the diagnostic system 1000 will be described. The basic configuration, measurement equation, and operation of the Coriolis mass flowmeter 1 will be described below in that order.

[0018] (1-3-1. Basic configuration of Coriolis mass flowmeter (1)) The basic configuration of the Coriolis mass flowmeter (1) will be described with reference to Fig. 2. Fig. 2 is a block diagram showing an example of the configuration of the Coriolis mass flowmeter (1) according to the embodiment. As shown in Fig. 2, the Coriolis mass flowmeter (1) has a detection unit (10), a conversion unit (20), and a display operation unit (30). In addition, the Coriolis mass flowmeter (1) is connected to an external device (31).

[0019] The detection unit (10) has one or more vibration tubes (11), a vibration unit (12), two or more sensors (13, 14) that measure vibration, and a temperature sensor (15). Here, the upstream sensor (13) transmits an upstream signal S1 (13a) to the conversion unit (20). Also, the downstream sensor (14) transmits a downstream signal S2 (14a) to the conversion unit (20). The temperature sensor (15) measures at least one of the temperature of the vibration tube (11) and the temperature of the fluid, and transmits a temperature signal T (15a) to the conversion unit (20). The vibration unit (12) receives an excitation signal drive (12a) from the conversion unit (20) and vibrates the vibration tube (11).

[0020] The conversion unit (20) has a drive control unit (21), a mass flow rate calculation unit (22), and a density calculation unit (23). The drive control unit (21) changes the excitation signal drive (12a) so that at least one of the amplitude of the upstream signal S1 (13a) and the amplitude of the downstream signal S2 (14a) becomes a target value. The mass flow rate calculation unit (22) calculates the mass flow rate from the phase difference and frequency of the upstream signal S1 (13a) and the downstream signal S2 (14a). The mass flow rate calculation unit (22) also performs temperature correction using the temperature signal T (15a). The density calculation unit (23) calculates the density of the fluid from at least one of the frequency of the upstream signal S1 (13a) and the frequency of the downstream signal S2 (14a). The density calculation unit (23) also performs temperature correction using the temperature signal T (15a).

[0021] The conversion unit (20) transmits the measured numerical value to the display operation unit (30) as a status value (32a). The conversion unit (20) also transmits the measured numerical value to the external device (31) as a status value (32b). Meanwhile, the display operation unit (30) transmits an operation amount (33a) to the conversion unit (20) and sets the operation and the measurement coefficient. The external device (31) also transmits an operation amount (33b) to the conversion unit (20) and sets the operation and the measurement coefficient.

[0022] Here, the conversion unit (20) may also have a calibration control unit (40b) that executes a calibration process for measuring at least one of mass flow rate and density for the Coriolis mass flowmeter (1). The conversion unit (20) may also have a diagnosis control unit (60b) that executes a diagnosis process for the Coriolis mass flowmeter (1).

[0023] The external device (31) holds a reference flow meter and calibrates the Coriolis mass flowmeter (1) by flowing a fluid, and includes a calibration control unit (40a) and a diagnosis control unit (60a). The calibration control unit (40a) includes a density calibration unit (51a) and a mass flow calibration unit (41a). The density calibration unit (51a) performs a density calibration process by measuring the frequency of a plurality of fluids having known densities. The mass flow calibration unit (41a) performs a mass flow calibration process. The diagnosis control unit (60a) also performs a diagnosis process by a diagnosis device (2) according to an embodiment described below.

[0024] Meanwhile, the calibration control unit (40b) of the conversion unit (20) of the Coriolis mass flowmeter (1) can also execute a calibration process, similar to the calibration control unit (40a) of the above-described external device (31). Moreover, the diagnosis control unit (60b) of the conversion unit (20) of the Coriolis mass flowmeter (1) can also execute a diagnosis process by a diagnosis device (2) according to an embodiment described below, similar to the diagnosis control unit (60a) of the above-described external device (31).

[0025] As described above, in the diagnostic system (1000) according to the embodiment, the diagnostic control unit (60) that executes various diagnostic processes is configured as either or both of the diagnostic control unit (60a) included in the external device (31) and the diagnostic control unit (60b) included in the conversion unit (20) inside the Coriolis mass flowmeter (1).

[0026] (1-3-2. Measurement formula of Coriolis mass flowmeter (1)) The measurement formula of the Coriolis mass flowmeter (1) is explained below. First, according to JIS B7555 "Explanation of flow measurement method by Coriolis meter (mass flow rate, density and volumetric flow rate measurement)", the mass flow rate Qm is measured by the following formula (1).

[0027]

number

[0028] Here, the variable Ks indicates the rigidity (spring constant) of the vibrating tube in the torsional direction. The variable ω indicates the vibration angular velocity of the vibrating tube. The variable d indicates the width of the U-shaped vibrating tube. The variable L indicates the length of the U-shaped vibrating tube in the vibration direction. The variable K1 indicates a constant. The variable ωs indicates the natural frequency in the torsional direction. The variable ωu indicates the natural angular frequency in the vibration direction. The variable θ0 indicates the phase difference corresponding to the torsion.

[0029] To measure the actual mass flow rate, the following measurement equation (2) is used.

[0030]

number

[0031] In the Coriolis mass flowmeter (1), the vibrating tube vibration frequency f and the phase difference θ0 are measured and multiplied by the flow measurement coefficient Cq to obtain the mass flow rate Qm. At this time, the flow measurement coefficient Cq is determined by the mass flow calibration unit (41) and is defined as the flow measurement coefficient Cq (28f). The phase difference θ0 is also measured and is defined as the phase difference θ (28d). The frequency f is also measured and is defined as the frequency f (28c). The mass flow rate Qm is then calculated using the above formula (2) and is defined as the mass flow rate Qm (28a).

[0032] In the vibration of the oscillating tube (11) of the Coriolis mass flowmeter (1), the relationship between the stiffness (spring constant) K of the oscillating tube (11), the total mass M of the oscillating tube (11), and the vibration angular frequency ω of the oscillating tube (11) is expressed by the following equation (3), where the variable f indicates the vibration frequency of the oscillating tube (11).

[0033]

number

[0034] The total mass M of the vibration tube (11) is the sum of the mass Mu of the vibration tube (11), the mass Md of accessories connected to the vibration tube (11), such as two or more sensors (13, 14) and the vibration unit (12), and the mass Mf of the fluid inside the vibration tube (11), and is expressed by the following equation (4).

[0035]

number

[0036] The mass Mf of the fluid in the vibration tube (11) is expressed by the following formula (5) using the volume of the fluid, that is, the internal volume V of the vibration tube (11), and the density ρ of the fluid.

[0037]

number

[0038] Here, from the above formulas (3), (4), and (5), the following formulas (6) and (7) are given.

[0039]

number

[0040]

number

[0041] Here, density ρ is a function of vibration frequency f. The above formula (7) includes the rigidity K of the vibrating tube (11), the internal volume V of the vibrating tube (11), the mass Mu of the vibrating tube (11) itself, and the mass Md of the accessories. Therefore, these coefficients must be calculated in order to measure the density.

[0042] A fluid with a known density ρ is measured. If the density is ρa, the vibration frequency is fa, and the rigidity of the vibration tube (11) is Ka, the following equation (8) is established from the above equation (6).

[0043]

number

[0044] In addition, if the stiffness Ka of the vibration pipe (11) is equal to the stiffness K of the vibration pipe (11) during measurement, it is expressed by the following formula (9).

[0045]

number

[0046] Incidentally, the rigidity of the vibration pipe (11) changes depending on the temperature, etc., so strictly speaking, the above formula (9) does not hold. Therefore, correction based on the temperature, etc. is required.

[0047] From the above equations (6), (8), and (9), the following equation (10) is obtained.

[0048]

number

[0049] Here, we define the density measurement coefficient Cd. As expressed by the following formula (11), the density measurement coefficient Cd is the sum of the mass of the vibration tube and accessories divided by the internal volume of the vibration tube, and has the same units as density.

number

[0050] Moreover, from the above formulas (10) and (11), the following formulas (12) and (13) hold true.

[0051]

number

[0052]

number

[0053] In the Coriolis mass flowmeter (1), the density measurement coefficient Cd and frequency fa are determined by the density calibration unit (51) and are defined as the density measurement coefficient Cd (28k) and the density measurement coefficient fa (28l), respectively. Also, the vibration frequency f of the vibration tube (11) is measured and defined as the frequency f (28c). Then, the density ρ is calculated from the above formula (12) and defined as the density ρ (28b).

[0054] Here, the above formula (12) shows that if the density measurement coefficient Cd and the frequency fa at the fluid density ρa are measured in advance, the density ρ of the unknown fluid can be calculated from the frequency f. In this case, the fluid density ρa and frequency fa are the values ​​of air or vacuum at standard temperature and pressure. When measuring liquids, the span error can be reduced by using the density of a liquid with a close density, such as water.

[0055] Moreover, the above formula (13) indicates that as the density ρ increases, the frequency f decreases. Furthermore, as the density measurement coefficient Cd increases, the change in frequency f relative to the change in density ρ decreases.

[0056] From the above, the relationship between the density measurement coefficient Cd and the rigidity K is expressed by the following equation (14).

[0057]

number

[0058] (1-3-3. Operation of Coriolis mass flowmeter (1)) The operation of the Coriolis mass flowmeter (1) will be described with reference to FIG. 3. FIG. 3 is a diagram showing an example of a measurement process of the Coriolis mass flowmeter (1) according to the embodiment. As shown in FIG. 3, the Coriolis mass flowmeter (1) has a detection unit (10) and a conversion unit (20). The detection unit (10) also has an excitation unit (12), an upstream sensor (13), a downstream sensor (14), and a temperature sensor (15). The conversion unit (20) also has a drive control unit (21) including an amplitude calculation unit (21a), an amplitude control unit (21b), a multiplier (21c), an excitation circuit (21d), and a current amplitude calculation unit (21e), a mass flow rate calculation unit (22), a density calculation unit (23), a phase difference calculation unit (24a), a frequency calculation unit (24b), an amplitude calculation unit (24c), an amplitude calculation unit (24d), a temperature calculation unit (24e), and a pressure selection switch (24f).

[0059] First, the upstream sensor (13) of the detection unit (10) outputs an upstream signal S1 (13a), and the downstream sensor (14) of the detection unit (10) outputs a downstream signal S2 (14a).

[0060] Next, the drive control section (21) of the conversion section (20) controls the excitation signal drive (12a) so that the amplitude of the upstream signal S1 (13a) becomes the amplitude target value (27c). Here, the amplitude calculation section (21a) outputs the amplitude of the upstream signal S1 (13a). The amplitude control section (21b) calculates the drive gain (27b) from the amplitude calculated by the amplitude calculation section (21a) and the amplitude target value (27c). At this time, P control, PI control, or the like is used. The multiplier (21c) multiplies the upstream signal S1 (13a) by the drive gain (27b) to calculate a control signal. The excitation circuit (21d) creates the excitation signal drive (12a) from the control signal. Then, the excitation section (12) of the detection section (10) is driven by the excitation signal drive (12a). At this time, the excitation section (12) converts the current into a force. Moreover, the current amplitude calculation unit (21e) outputs the amplitude of the current value output by the excitation circuit (21d) as a drive current (27a).

[0061] 3, the amplitude control is performed by the upstream signal S1 (13a), but the amplitude control can also be performed by the downstream signal S2 (14a). Also, both the upstream signal S1 (13a) and the downstream signal S2 (14a) can be used.

[0062] The amplitude calculation unit (24c) of the conversion unit (20) outputs the amplitude S1 (27d) of the upstream signal S1 (13a). The amplitude calculation unit (24d) outputs the amplitude S2 (27e) of the downstream signal S2 (14a). The amplitude calculation units (24c, 24d) can perform output processing simultaneously with the phase difference calculation using a Hilbert transform or the like. The phase difference calculation unit (24a) of the conversion unit (20) calculates the phase difference θ (28d) from the upstream signal S1 (13a) and the downstream signal S2 (14a). The frequency calculation unit (24b) of the conversion unit (20) calculates the frequency f (28c) from at least one of the upstream signal S1 (13a) and the downstream signal S2 (14a). The temperature calculation unit (24e) of the conversion unit (20) calculates the temperature T (28e) from the temperature signal T (15a).

[0063] The mass flow calculation unit (22) of the conversion unit (20) calculates the mass flow rate Qm (28a) from the phase difference θ (28d) and the frequency f (28c) by the above-mentioned formula (2). The mass flow calculation unit (22) calculates the mass flow rate Qm (28a) by using the flow measurement coefficient Cq (28f). Here, the mass flow rate Qm (28a) depends on temperature, pressure, and density. Since the Coriolis mass flowmeter (1) cannot measure pressure, an external pressure gauge (29) is attached to obtain an external input pressure Pin (28r) or set a default pressure Ps (28q). When the pressure gauge (29) is connected, a pressure gauge connection signal (28s) is set. The pressure selection switch (24f) outputs the external input pressure Pin (28r) or the default pressure Ps (28q) according to the pressure gauge connection signal (28s), and sets it as the pressure P (28t). At this time, the mass flow rate calculator (22) corrects the mass flow rate Qm (28a) by using a flow rate measurement correction coefficient (28g) and at least one of the temperature T (28e), the density ρ (28b), and the pressure P (28t).

[0064] The density calculation unit (23) of the conversion unit (20) calculates the density ρ (28b) from the frequency f (28c) by the above-mentioned formula (12). The density calculation unit (23) calculates the density ρ (28b) by using the density measurement coefficient Cd (28k) and the density measurement coefficient fa (28l). Here, the density ρ (28b) depends on the temperature and the pressure. At this time, the density calculation unit (23) corrects the density ρ (28b) by using the density measurement correction coefficient (28m) and at least one of the temperature T (28e) and the pressure P (28t). Note that this correction is not a correction for a change in the measurement target, but a correction for a situation in which the above-mentioned formula (9) does not hold due to a change in the rigidity of the vibration tube (11) or the like. The density calculation unit (23) corrects the frequency to a specified state, for example, 20° C. and 1 atm.

[0065] The conversion unit (20) stores all of the coefficients, set values, and measurement results used in the above-mentioned calculations as control parameters (27) and parameters (28). The calibration control unit (40) and diagnosis control unit (60) operate by reading and setting the values ​​of these parameters.

[0066] (1-4. Issues with the prior art) Below, the problems with the conventional technology will be described in the order of stiffness damping diagnosis processing, corrosion diagnosis processing, density calibration processing, flow rate calibration processing, and prediction processing for maintenance, etc.

[0067] (1-4-1. Stiffness damping diagnostic processing and corrosion diagnostic processing) In the conventional stiffness attenuation diagnosis process and corrosion diagnosis process, corrosion is judged based on stiffness, and thickness change is not directly obtained. Here, the cause of stiffness change is not limited to corrosion. The stiffness attenuation diagnosis process and thickness diagnosis process executed by the diagnosis system (1000) contribute to solving the above problems.

[0068] (1-4-2. Density calibration process) In conventional density calibration processing, changing parameters creates discontinuity in the measurement results. This becomes a factor of variation, especially when calibration is performed frequently. Even with conventional processing, it is possible to calculate the density error from the difference with the known density of the fluid used during calibration, but the density error depends on the density of the object to be measured. Here, since the purpose of a Coriolis mass flowmeter is to measure mass flow rate and density, it is necessary to understand the density error in order to guarantee performance. The density error diagnosis and simple correction processing executed by the diagnostic system (1000) contributes to solving the above problems.

[0069] (1-4-3. Flow rate calibration process) Conventional flow rate calibration processes require a device that provides a known flow rate or a standard mass flow meter, and the calibration device is large in size. In addition, in conventional processes, mass flow rate calibration requires removing the device and transporting it to a calibration facility for calibration, which results in a large amount of expense and time when the flow meter cannot be used. Since measurement accuracy is important, calibration is performed during regular maintenance. In conventional processes, there are attempts to calibrate Coriolis mass flow meters at the site of use, but this requires a compact flow rate calibration device. Here, since the purpose of the Coriolis mass flow meter is to measure mass flow rate and density, it is necessary to grasp the flow rate error in order to guarantee performance. The flow rate error diagnosis and simple correction process performed by the diagnostic system (1000) contributes to solving the above problems.

[0070] (1-4-4. Prediction of maintenance, etc.) Conventional maintenance and replacement timing prediction processes predict timing based on stiffness or damping. It is difficult to determine the value that requires maintenance based on these parameters alone. The timing prediction diagnostic process executed by the diagnostic system (1000) contributes to solving the above problem.

[0071] (1-5. Effects of diagnostic system (1000)) In the following, the effects of the diagnostic system (1000) will be described in the order of stiffness damping diagnostic processing, wall thickness diagnostic processing, density error diagnostic and simple correction processing, flow rate error diagnostic and simple correction processing, and timing prediction diagnostic processing.

[0072] (1-5-1. Stiffness damping diagnostic process and wall thickness diagnostic process) As described above, in the diagnostic system (1000), the diagnostic device (2) applies a driving force with a constant oscillation feedback gain to the Coriolis mass flowmeter (1), which measures the flow rate and density of the fluid flowing through the vibrating tube (11) based on the Coriolis force acting on the vibrating tube (11), to generate a stiffness damping diagnostic result related to the stiffness change of the vibrating tube (11), executes a calculation related to the thickness of the vibrating tube (11) based on the generated stiffness damping diagnostic result, and generates a thickness diagnostic result related to the thickness change of the vibrating tube (11). In addition, the diagnostic device (2) generates a thickness diagnostic result including at least one of the inner diameter, thickness, thickness change, and thickness change rate of the vibrating tube (11) using the stiffness change rate of the vibrating tube (11) indicated by the stiffness damping diagnostic result and the design value of the vibrating tube (11), and detects an abnormality related to the vibrating tube (11) when the thickness diagnostic result is equal to or greater than a threshold value.

[0073] Therefore, in the diagnostic system (1000), the change in the wall thickness of the vibrating tube (11) can be directly obtained, so that the failure or performance deterioration of the Coriolis mass flowmeter (1) can be easily diagnosed.

[0074] (1-5-2. Density error diagnosis and simple correction process) As described above, in the diagnostic system (1000), the diagnostic device (2) executes calculations related to the density of the fluid based on the thickness diagnostic result, and generates a density diagnostic result related to the density error of the fluid. Therefore, in the diagnostic system (1000), it is possible to estimate the change in the density measurement coefficient from the stiffness change, the thickness change, etc., and to simply correct the density, without performing density calibration in a calibration facility.

[0075] (1-5-3. Flow rate error diagnosis and simple correction process) As described above, in the diagnostic system (1000), the diagnostic device (2) executes calculations related to the flow rate of the fluid based on the density diagnostic result, and generates a flow rate diagnostic result related to the error in the flow rate of the fluid. Therefore, in the diagnostic system (1000), the mass flow rate can be easily corrected based on changes in stiffness, thickness, and density measurement coefficient, without calibrating the mass flow rate in a calibration facility.

[0076] (1-5-4. Timing prediction diagnostic processing) As described above, in the diagnostic system (1000), the diagnostic device (2) predicts the occurrence of a fault in the Coriolis mass flowmeter (1), the time required for maintenance or equipment replacement, the operating time, or the integrated flow rate of the fluid based on the stiffness damping diagnostic result, the wall thickness diagnostic result, the density diagnostic result, or the flow rate diagnostic result, and outputs the result as a timing prediction diagnostic result. Therefore, in the diagnostic system (1000), by using any of the results of each diagnostic process, the timing of maintenance, etc. can be predicted more accurately and easily.

[0077] 2. Configuration of each device in the diagnostic system (1000) The functional configuration of each device of the diagnostic system (1000) shown in FIG. 1 will be described with reference to FIG. 4. FIG. 4 is a block diagram showing an example of the configuration of each device of the diagnostic system according to the embodiment. Below, an example of the configuration and processing of the diagnostic system (1000) as a whole will be described, and then an example of the configuration of the diagnostic device (2) will be described. In FIG. 4, the solid arrows indicate information such as signals, and the dashed arrows indicate triggers for processing.

[0078] (2-1. Example of the overall configuration of the diagnostic system (1000)) As shown in FIG. 4, the diagnostic system (1000) has a Coriolis mass flowmeter (1), a diagnostic device (2), and a calibration device (3). In FIG. 4, the Coriolis mass flowmeter (1), the diagnostic device (2), and the calibration device (3) are shown as separate devices, but two or three of the above three devices may be integrated into one configuration. The configuration and processing of the Coriolis mass flowmeter (1) are common to the configuration and processing of the Coriolis mass flowmeter (1) described in (1-3-1. Basic configuration of the Coriolis mass flowmeter (1)), so a description thereof will be omitted. The configuration and processing of the calibration control unit (40) of the calibration device (3) are common to the external device (31) or the calibration control unit (40) in the conversion unit (20) of the Coriolis mass flowmeter (1) described in (1-3-1. Basic configuration of the Coriolis mass flowmeter (1)), so a description thereof will be omitted.

[0079] (2-2. Overall processing of diagnostic system (1000)) As shown in FIG. 4, the diagnostic device (2) executes diagnostic processing in the order of stiffness damping diagnosis processing by a stiffness damping diagnosis unit (61), thickness diagnosis processing by a thickness diagnosis unit (70), density error diagnosis and simple correction processing by a density error diagnosis simple correction unit (80), flow rate error diagnosis and simple correction processing by a flow rate error diagnosis simple correction unit (90), and timing prediction diagnosis processing by a timing prediction diagnosis unit (100).

[0080] (2-2-1. Stiffness damping diagnostic processing) As the first process, the stiffness damping diagnosis process will be described. First, the stiffness damping diagnosis unit (61) of the diagnosis device (2) outputs a stiffness damping diagnosis result (221). At this time, the stiffness damping diagnosis unit (61) sets a fixed drive gain (242) and a drive gain selection (240) for the drive control unit (21) of the Coriolis mass flowmeter (1) and changes the excitation signal drive (12a) given to the vibration unit (12) of the Coriolis mass flowmeter (1). Then, the stiffness damping diagnosis unit (61) outputs a stiffness damping diagnosis result (221) including a stiffness change rate aKc (221a) from changes in the amplitude S1 (27d), the amplitude S2 (27e), the frequency f (28c), the temperature T (28e), the drive current (27a), and the drive gain (27b). In addition, the stiffness damping diagnosis unit (61) sets a stiffness damping diagnosis completion signal (231) at the end of the process.

[0081] (2-2-2. Thickness diagnosis process) As the second process, the wall thickness diagnosis process will be described. First, the wall thickness diagnosis unit (70) of the diagnosis device (2) executes the process when the stiffness attenuation diagnosis completion signal (231) is set. The wall thickness diagnosis unit (70) calculates the change in wall thickness from the stiffness attenuation diagnosis result (221) and updates the wall thickness diagnosis result (321). Here, the wall thickness diagnosis result (321) takes over the stiffness change amount, the damping change amount, and the Q value change amount from the stiffness attenuation diagnosis result (221). Then, the wall thickness diagnosis unit (70) resets the stiffness attenuation diagnosis completion signal (231) when the process ends. The wall thickness diagnosis unit (70) also sets the wall thickness diagnosis completion signal (331).

[0082] (2-2-3. Density error diagnosis and simple correction process) As the third process, the density error diagnosis and simple correction process will be described. First, the density error diagnosis simple correction unit (80) executes the process when the thickness diagnosis completion signal (331) or the density calibration completion signal (122) is set. At this time, when the thickness diagnosis completion signal (331) is set, the density error diagnosis simple correction unit (80) obtains the density diagnosis result (421) from the thickness diagnosis result (321). Then, the density error diagnosis simple correction unit (80) updates the density measurement coefficient Cd (28k) and the density measurement coefficient fa (28l) to reduce the density error. On the other hand, when the density calibration completion signal (122) is set, the density error diagnosis simple correction unit (80) performs an initialization operation of the density error diagnosis. Then, when the process ends, the density error diagnosis simple correction unit (80) resets the thickness diagnosis completion signal (331) and the density calibration completion signal (122). Furthermore, the density error diagnosis simple correction unit (80) sets a density diagnosis completion signal (431) when the process is completed.

[0083] (2-2-4. Flow rate error diagnosis and simple correction process) As the fourth process, the flow rate error diagnosis and simple correction process will be described. First, the flow rate error diagnosis simple correction unit (90) executes the process when the density diagnosis completion signal (431) or the flow rate calibration completion signal (121) is set. At this time, when the density diagnosis completion signal (431) is set, the flow rate error diagnosis simple correction unit (90) obtains the flow rate diagnosis result (521) including the flow rate correction coefficient from the wall thickness diagnosis result (321). Then, the flow rate error diagnosis simple correction unit (90) updates the flow rate correction coefficient fk (28u) to reduce the flow rate error. On the other hand, when the flow rate calibration completion signal (121) is set, the flow rate error diagnosis simple correction unit (90) performs an initialization operation of the flow rate error diagnosis. Then, when the process ends, the flow rate error diagnosis simple correction unit (90) resets the density diagnosis completion signal (431) and the flow rate calibration completion signal (121).

[0084] (2-2-5. Timing prediction diagnostic processing) As the fifth process, the timing prediction diagnosis process will be described. First, the timing prediction diagnosis unit (100) predicts the time when the diagnosis result will reach a target value by using the stiffness damping diagnosis result (221), the wall thickness diagnosis result (321), the density diagnosis result (421), or the flow rate diagnosis result (521). At this time, the timing prediction diagnosis unit (100) sets a threshold value to predict the time required until a failure occurs or a state in which maintenance is required, the operating time, or the accumulated flow rate of the fluid.

[0085] (2-3. Configuration example of diagnostic device (2)) A configuration example of the diagnostic device (2) according to the embodiment will be described below. As shown in Fig. 4, the diagnostic device (2) has a diagnostic control unit (60), a transmitting / receiving unit (200), and a notification unit (300). The diagnostic device (2) may also have an input unit (e.g., a keyboard, a mouse, etc.) that accepts various operations from an administrator of the diagnostic device (2), and a display unit (e.g., a liquid crystal display, etc.) that displays various information.

[0086] (2-3-1. Diagnosis control unit (60)) The diagnostic control unit (60) is realized, for example, by a central processing unit (CPU), a micro processing unit (MPU), etc., executing various programs (corresponding to an example of an information processing program) stored in a storage device inside the diagnostic device (2) using a RAM as a working area. The diagnostic control unit (60) is also realized, for example, by an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0087] As shown in Fig. 4, the diagnosis control unit (60) has a stiffness damping diagnosis unit (61), a wall thickness diagnosis unit (70), a density error diagnosis simple correction unit (80), a flow rate error diagnosis simple correction unit (90), and a timing prediction diagnosis unit (100), and realizes or executes the functions and actions of information processing described below. The internal configuration of the diagnosis control unit (60) is not limited to the configuration shown in Fig. 4, and may be other configurations as long as they perform information processing described below. Furthermore, the connection relationship between the various processing units in the diagnosis control unit (60) is not limited to the connection relationship shown in Fig. 4, and may be other connection relationships.

[0088] (2-3-1-1. Stiffness damping diagnostic unit (61)) The stiffness damping diagnosis unit (61) applies a driving force with a constant oscillation feedback gain (drive gain) to the vibrating tube (11) in a Coriolis mass flowmeter (1), which measures the flow rate and density of a fluid flowing through the vibrating tube (11) based on the Coriolis force acting on the vibrated vibrating tube (11), to generate a stiffness damping diagnosis result (221) regarding a stiffness change in the vibrating tube (11).

[0089] For example, the stiffness damping diagnosis unit (61) sets a fixed drive gain (242) and a drive gain selection (240) for the drive control unit (21) of the Coriolis mass flowmeter (1), changes the excitation signal drive (12a) provided to the vibration unit (12) of the Coriolis mass flowmeter (1), and generates a stiffness damping diagnosis result (221) including a stiffness change rate aKc (221a) from changes in the amplitude S1 (27d), the amplitude S2 (27e), the frequency f (28c), the temperature T (28e), the drive current (27a), the drive gain (27b), etc.

[0090] (2-3-1-2. Thickness Diagnosis Section (70)) The wall thickness diagnosis unit (70) executes a calculation regarding the wall thickness of the vibration pipe (11) based on the stiffness damping diagnosis result (221) and generates a wall thickness diagnosis result (321) regarding a change in the wall thickness of the vibration pipe (11). For example, the wall thickness diagnosis unit (70) uses the stiffness change rate aKc (221a) of the vibration pipe (11) indicated by the stiffness damping diagnosis result (221) and the vibration pipe design values ​​(303) (vibration pipe inner diameter d, vibration pipe outer diameter D) of the vibration pipe (11) to generate a wall thickness diagnosis result (321) including at least one of the inner diameter dcc, wall thickness tcc, wall thickness change dtc, and wall thickness change rate rtc of the vibration pipe (11), and detects an abnormality regarding the vibration pipe (11) when the wall thickness diagnosis result (321) is equal to or greater than a threshold value.

[0091] The thickness diagnosis unit (70) can also generate a thickness diagnosis result (321) by using an equation for the second moment of area of ​​a cantilever beam having a circular tubular cross section and correcting it with an approximation line or approximation curve.

[0092] (2-3-1-3. Density error diagnosis and simple correction unit (80)) The density error diagnosis simple correction unit (80) performs calculations related to the density of the fluid based on the wall thickness diagnosis result (321) to generate a density diagnosis result (421) related to the density error of the fluid. For example, the density error diagnosis simple correction unit (80) calculates density measurement coefficients (Cdcc, facc) using the results related to the stiffness change and the wall thickness change, and performs update control of the density measurement coefficients used by the Coriolis mass flowmeter (1) to measure the density based on the calculated density measurement coefficients.

[0093] At this time, the density error diagnosis simple correction unit (80) calculates the density fluctuation Δρ when the density measurement coefficients are updated, using the density measurement coefficients (Cdc0, fac0) before the change, the calculated density measurement coefficients (Cdcc, facc), and the density ρt of the object to be measured, and if the density fluctuation exceeds an allowable value, updates the density measurement coefficients used by the Coriolis mass flowmeter (1) to measure density. The density error diagnosis simple correction unit (80) can also calculate at least one of the density measurement coefficient change rate (aCdc, afac) and the density error Δρ0, using the density measurement coefficients (Cdc0, fac0) before the change, the calculated density measurement coefficients (Cdcc, facc), and the density ρt of the object to be measured.

[0094] (2-3-1-4. Flow rate error diagnosis simple correction unit (90)) The flow rate error diagnosis simple correction unit (90) performs calculations related to the flow rate of the fluid based on the density diagnosis result (421) and generates a flow rate diagnosis result (521) related to the flow rate error of the fluid. For example, the flow rate error diagnosis simple correction unit (90) calculates a flow rate correction coefficient fkq using at least one of the stiffness change rate aKc, the wall thickness change rate rtc, and the change rates (aCdc, afac) of the density measurement coefficients, and performs update control of the flow rate correction coefficient used by the Coriolis mass flowmeter (1) to measure the flow rate based on the calculated flow rate correction coefficient.

[0095] At this time, the flow rate error diagnosis simple correction unit (90) calculates the flow rate fluctuation rate rqd when the flow rate correction coefficient is updated, using the flow rate correction coefficient fk before the change and the calculated flow rate correction coefficient fkq, and if the flow rate fluctuation rate exceeds an allowable value, updates the flow rate measurement coefficient used by the Coriolis mass flowmeter (1) to measure the flow rate. The flow rate error diagnosis simple correction unit (90) can also determine in advance the type of rate of change and weighting coefficient used in calculating the flow rate correction coefficient fkq from the results of a simulation or experiment.

[0096] (2-3-1-5. Timing prediction diagnosis unit (100)) The timing prediction diagnosis unit (100) predicts the occurrence of a fault in the Coriolis mass flowmeter (1), the time required for maintenance or equipment replacement, the operating time, or the integrated flow rate of the fluid based on the stiffness damping diagnosis result (221), the wall thickness diagnosis result (321), the density diagnosis result (421), or the flow rate diagnosis result (521), and outputs the result as a timing prediction diagnosis result (603).

[0097] For example, the timing prediction diagnosis unit (100) uses at least one of the inner diameter dcc, the thickness tcc, the thickness change dtc, and the thickness change rate rtc of the vibration pipe (11) as the thickness diagnosis result (321) and outputs it as the timing prediction diagnosis result (603). Also, the timing prediction diagnosis unit (100) uses at least one of the calculated density measurement coefficient (Cdcc, facc), the density measurement coefficient change rate (aCdc, afac), and the density error Δρ0 as the density diagnosis result (421) and outputs it as the timing prediction diagnosis result (603). Also, the timing prediction diagnosis unit (100) uses at least one of the flow correction coefficient fkq and the flow error rate rqe as the flow rate diagnosis result (521) and outputs it as the timing prediction diagnosis result (603).

[0098] Moreover, the timing prediction diagnosis unit (100) obtains an approximation line or an approximation curve showing the change with time of a parameter included in the stiffness damping diagnosis result (221), the wall thickness diagnosis result (321), the density diagnosis result (421) or the flow rate diagnosis result (521), the change with respect to the operating time of the parameter, or the change with respect to the integrated flow rate of the parameter, and predicts the time, operating time or integrated flow rate of the fluid until the approximation line or the approximation curve reaches a diagnostic target value defined as a state in which a fault has occurred and maintenance or replacement of equipment is required, and outputs the result as a timing prediction diagnosis result (603).

[0099] (2-3-2. Transmitter / receiver (200)) The transmitting / receiving unit (200) is realized by, for example, a network interface card (NIC) etc. The transmitting / receiving unit (200) is connected to a predetermined communication network by wire or wirelessly, and transmits and receives information to and from various devices.

[0100] (2-3-3. Notification Department (300)) The notification unit (300) notifies of an abnormality related to the vibrating pipe (11) when the stiffness damping diagnosis result (221), the wall thickness diagnosis result (321), the density diagnosis result (421) or the flow rate diagnosis result (521) exceeds a predetermined alarm value.

[0101] [3. Details of each process of the diagnostic device (2)] 5 to 32 and equations, the details of each process of the diagnosis device (2) according to the embodiment will be described. The following will explain the stiffness damping diagnosis process, the wall thickness diagnosis process, the density error diagnosis and simple correction process, the flow rate error diagnosis and simple correction process, and the timing prediction diagnosis process in that order.

[0102] (3-1. Stiffness damping diagnostic processing) 5 to 11 and equations, the stiffness attenuation diagnosis process executed by the stiffness attenuation diagnosis unit (61) of the diagnosis device (2) according to the embodiment will be described. Below, after explaining the theoretical equation of the stiffness attenuation diagnosis process, the whole stiffness attenuation diagnosis process, the execution determination process, the stiffness attenuation measurement process, the stiffness attenuation initialization process, and the stiffness attenuation determination process will be described in this order.

[0103] (3-1-1. Theoretical formula for stiffness damping diagnostic processing) The theoretical formula for the stiffness damping diagnostic process will be described below. First, the vibration equation of the vibrating pipe (11) is given by the following formula (15).

[0104]

number

[0105] Here, in the above formula (15), the variable x indicates the vibration displacement of the vibration tube (11), the variable M indicates the total mass of the vibration tube (11), the variable D indicates the damping coefficient, the variable K indicates the rigidity of the vibration tube (11), and the variable G indicates the feedback gain. In addition, in the above formula (15), "Gdx / dt" on the right side corresponds to the action force applied to the vibration tube (11) by the vibration unit (12). The upstream sensor (13) and the downstream sensor (14) output the upstream signal S1 (13a) and the downstream signal S2 (14a) proportional to the speed signal dx / dt. The vibration unit (12) generates an action force proportional to the current of the excitation signal drive (12a). The upstream signal S1 (13a) is multiplied by the drive gain (27b) and converted into a current by the excitation circuit (21d) to drive the vibration tube (11).

[0106] Dividing both sides of the above equation (15) by the mass M gives the following equation (16): Moreover, using the damping ratio ζ and the angular frequency ω gives the following equations (17) to (20).

[0107]

number

[0108]

number

[0109]

number

[0110]

number

[0111]

number

[0112] Here, the solutions of the above equation (20) are the following equations (21) to (23).

[0113]

number

[0114]

number

[0115]

number

[0116] The upstream sensor (13) and the downstream sensor (14) output a value proportional to the speed signal dx / dt expressed by the following equation (24).

[0117]

number

[0118] When measuring the mass flow rate and density, the drive gain (27b) is controlled by AGC (Auto Gain Control), and the attenuation is cancelled by the gain G0 expressed by the following equation (25).

[0119]

number

[0120] As expressed by the following two equations (26), the rate of increase / decrease in the gain G1 is α1, and the rate of increase / decrease in the gain G2 is α2.

[0121]

number

[0122] When mass M is calculated from the above formula (26), the following formula (27) is obtained.

[0123]

number

[0124] The stiffness K is calculated from the angular frequency ω using the following equation (28).

[0125]

number

[0126] The damping coefficient D is calculated using the following equation (29). Note that the damping coefficient D is the same as the gain G0 (drive gain).

[0127]

number

[0128] The Q value Qf is calculated as shown in the following equation (30).

[0129]

number

[0130] In the stiffness damping diagnosis process described above, two-system diagnosis is possible using the upstream signal S1 (13a) and the downstream signal S2 (14a). Here, the signal number is indicated by the variable x. The amplitude of the upstream signal S1 (13a) is x=1, and the amplitude of the downstream signal S2 (14a) is x=2.

[0131] In addition, in the stiffness attenuation diagnosis process described above, the drive gain (27b) is fixed at two values, and the rate of increase or decrease in amplitude is measured to diagnose stiffness and attenuation. At this time, the fixed value is set based on the drive gain (27b) during AGC and the previous increase or decrease status. If it is smaller than the drive gain (27b) during AGC, the amplitude is attenuated, and if it is larger, it is increased.

[0132] The rates of increase / decrease αx1 and αx2 are measured from the rate of change of the amplitude per unit time. From the above formula (24), the amplitude A(t) at time t, which is expressed by the following formula (31), is found.

[0133]

number

[0134] Here, the amplitude A0 in the above formula (31) represents the amplitude at time t = 0. Next, when the rate of increase or decrease αx1 is calculated from the amplitude Ax1 at time t1 and Ax2 at time t2, the following formulas (32) to (35) are obtained.

[0135]

number

[0136]

number

[0137]

number

[0138]

number

[0139] Similarly, when the rate of increase or decrease αx2 is calculated from the amplitude Ax3 at time t3 and Ax4 at time t4, the following formula (36) is obtained.

[0140]

number

[0141] In the stiffness damping diagnostic process described above, the drive gain (27b) is used as the feedback gain G. Here, the drive gain (27b) is a value that adjusts not only the fluctuation of the vibration tube (11) but also the characteristics of the sensors (13, 14), the characteristic fluctuation of the vibration unit (12), and the characteristic fluctuation of the excitation circuit (21d).

[0142] In this case, the characteristics of the sensor (13, 14), the vibration unit (12), and the excitation circuit (21d) cannot be measured directly. The gain that cannot be measured is designated as GT1. Since there are individual differences in characteristics, a judgment is made by calculating the rate of change from a reference value. Since the sensors (13, 14) and the vibration unit (12) are affected by temperature, temperature compensation is performed to maintain accuracy. The following equation (37) is an example of temperature compensation using a quadratic equation. Here, coefficients CT1 and CT2 are constants determined by the material and are calculated in advance. The temperature may be set at 20°C.

[0143]

number

[0144] The gain Gc obtained by dividing the drive current (27a) by the amplitude S1 (27d) may be used as the feedback gain G. The drive current (27a) is a variable Id, and the amplitude S1 (27d) is a variable A1. Each indicates an amplitude value. If the unmeasurable gain is GT2, the following equation (38) is obtained.

[0145]

number

[0146] As in the above formula (38), by using the gain Gc, the characteristics of the excitation circuit (21d) can be excluded.

[0147] Substituting the above equations (37) and (38) into the above equation (27) to find the mass M, we obtain the following two equations (39). Here, the mass Mxd indicates the mass found using the fixed drive gain (242) calculated using the above equation (37). Also, the mass Mxg indicates the mass found using the gain Gc calculated using the above equation (38).

[0148]

number

[0149] The stiffness K is calculated from the corrected frequency fc as shown in the following formula (40).

[0150]

number

[0151] The damping coefficient D is calculated using the second equation of the following formula (41).

[0152]

number

[0153] The Q value Qf is calculated using the following formula (42).

[0154]

number

[0155] The stiffness K and damping coefficient D obtained by the theoretical formula of the stiffness damping diagnosis process described above are not absolute values, so it is necessary to evaluate the change ratio. The change rate of the Q value Qf is also evaluated. Each change rate is expressed by the following formulas (43) to (45).

[0156]

number

[0157]

number

[0158]

number

[0159] Here, in the above formulas (43) to (45), the variable y indicates the measurement method, d indicates the drive gain, and g indicates the result using the gain. The denominator indicates the initial value. The stiffness change rate aKxy indicates the stiffness change rate aKc (221a). The damping change rate aDxy indicates the damping change rate aDc (221b). The Q value change rate aQfxy indicates the Q value change rate aQc (221c).

[0160] Anomalies can be detected using the stiffness change rate aKc (221a), damping change rate aDc (221b), and Q-factor change rate aQc (221c). The absolute value of the change ratio from the initial state is evaluated. In this case, the conditional expressions are the following expressions (46) to (48).

[0161]

number

[0162]

number

[0163]

number

[0164] Here, in the above formulas (46) to (48), the threshold aKerror indicates the stiffness change rate tolerance (222m), the threshold aDerror indicates the damping change rate tolerance (222n), and the threshold aQferror indicates the Q factor change rate tolerance (222o).

[0165] Corrosion can be determined from the rate of change in stiffness aKc (221a). When corrosion occurs, stiffness decreases. In other words, the rate of change in stiffness aKc (221a) becomes smaller than 1. In this case, the conditional formula is given by the following formula (49).

[0166]

number

[0167] Here, the judgment value aKcor in the above formula (49) is set as the corrosion judgment value (222p).

[0168] Adhesion can also be determined from changes in the Q value or damping and stiffness. If the Q value or damping decreases and there is no change in stiffness, adhesion is likely. If a soft substance adheres, there is no effect on stiffness. The Q value or damping decreases as the adhesion absorbs forces. Since the Q value and damping depend on the object being measured, care must be taken when making a judgment. In this case, the conditional formula is given by the following formula (50).

[0169]

number

[0170] Here, in the above formula (50), the judgment value aDad, the judgment value aQfad, and the judgment value aKad are defined as the adhesion judgment value (222q).

[0171] (3-1-2. Overall processing of stiffness damping diagnosis) The overall stiffness damping diagnosis process will be described with reference to Fig. 5 to Fig. 6. Fig. 5 to Fig. 6 are diagrams showing an example of the overall stiffness damping diagnosis process according to the embodiment. Below, an overview of the overall stiffness damping diagnosis process showing the relationship with the Coriolis mass flowmeter (1) will be described, and then the configuration of the stiffness damping diagnosis unit (61) of the diagnosis device (2) will be described.

[0172] (3-1-2-1. Overview of the entire stiffness damping diagnostic process) An overview of the entire stiffness damping diagnosis process will be described with reference to Fig. 5. As shown in Fig. 5, in the drive control section (21) of the Coriolis mass flowmeter (1), the drive gain selector (21f) selects the AGC drive gain (241) output from the amplitude control section (21b) and a fixed drive gain (242) according to the drive gain selection (240) output from the stiffness damping diagnosis section (61) of the diagnosis device (2). Then, the drive gain selector (21f) selects the fixed drive gain (242) when performing stiffness damping diagnosis.

[0173] Next, the stiffness attenuation diagnosis unit (61) sets the drive gain (27b) to the fixed drive gain (242), and performs stiffness and damping diagnosis from changes in the amplitude S1 (27d), the amplitude S2 (27e), and the drive current (27a). At this time, the stiffness attenuation diagnosis unit (61) uses the frequency f (28c). The stiffness attenuation diagnosis unit (61) also uses the temperature T (28e), the pressure P (28t), and the density measurement correction coefficient (28m) for correction.

[0174] (3-1-2-2. Configuration of stiffness damping diagnostic unit (61)) The configuration of the stiffness attenuation diagnosis unit (61) will be described with reference to Fig. 6. As shown in Fig. 6, the stiffness attenuation diagnosis unit (61) is a part of the diagnosis control unit (60) of the diagnosis device (2), and executes a process of measuring changes in stiffness and damping and diagnosing them. The stiffness attenuation diagnosis unit (61) also has an execution determination unit (62), a stiffness attenuation measurement unit (63), a stiffness attenuation initialization unit (64), and a stiffness attenuation determination unit (65), and executes an execution determination process, a stiffness attenuation measurement process, a stiffness attenuation initialization process, and a stiffness attenuation determination process, respectively.

[0175] The stiffness damping diagnosis unit (61) executes processing when the stiffness damping diagnosis execution signal (230) is set. First, the execution determination unit (62) selects the processing to be executed based on the stiffness damping diagnosis execution signal (230) and the stiffness damping diagnosis set value (222). At this time, if the execution determination unit (62) sets the initialization execution signal (223), the stiffness damping measurement unit (63) and stiffness damping initialization unit (64) execute processing. On the other hand, if the determination execution signal (224) is set, the stiffness damping measurement unit (63) and stiffness damping determination unit (65) execute processing.

[0176] Next, the stiffness damping measurement unit (63) measures stiffness and damping. The stiffness damping measurement unit (63) sets a fixed drive gain (242) and a drive gain selection (240) for the drive control unit (21) of the Coriolis mass flowmeter (1) and changes the operation of the drive gain selector (21f). The stiffness damping measurement unit (63) also calculates a stiffness damping diagnosis result (221) from changes in the control parameter (27) and the parameter (28). The stiffness damping measurement unit (63) executes processing when an initialization execution signal (223) or a determination execution signal (224) is set.

[0177] Next, the stiffness damping initialization unit (64) sets the result of measurement by the stiffness damping measurement unit (63) as the initial value of the stiffness damping diagnosis set value (222). The stiffness damping initialization unit (64) executes processing when the initialization execution signal (223) is set. The stiffness damping initialization unit (64) also resets the stiffness damping diagnosis execution signal (230). The stiffness damping initialization unit (64) also sets the stiffness damping diagnosis completion signal (231).

[0178] The stiffness attenuation determination unit (65) then calculates the rate of change from the result of measurement by the stiffness attenuation measurement unit (63). The stiffness attenuation determination unit (65) compares the rate of change with an allowable value and sets abnormality information. The stiffness attenuation determination unit (65) also resets the stiffness attenuation diagnosis execution signal (230). The stiffness attenuation determination unit (65) also sets the stiffness attenuation diagnosis completion signal (231). When the determination execution signal (224) is set, the stiffness attenuation determination unit (65) executes processing.

[0179] (3-1-3. Execution Determination Process) The execution determination process by the execution determination unit (62) of the stiffness attenuation diagnosis unit (61) will be described with reference to FIG. 7. FIG. 7 is a diagram showing an example of stiffness attenuation diagnosis process 1 according to the embodiment. As shown in FIG. 7, the execution determination unit (62) executes the process when a stiffness attenuation diagnosis execution signal (230) is set. The execution determination unit (62) also outputs an initialization execution signal (223) and a determination execution signal (224) based on the initial stiffness Kc0 (222e), the initial value acquisition command (222u) and the initial date and time (222x) as the stiffness attenuation diagnosis set value (222). The flow of the execution determination process will be described later in [5. Flow of each process of the diagnosis device (2)].

[0180] (3-1-4. Stiffness damping measurement processing) A stiffness attenuation measurement process by the stiffness attenuation measuring unit (63) of the stiffness attenuation diagnosis unit (61) will be described with reference to Figs. 8 and 9. Figs. 8 and 9 are diagrams showing an example of stiffness attenuation diagnosis process 2 according to the embodiment. Below, the configuration of the stiffness attenuation measuring unit (63) will be described, and then the signal waveforms during the operation of the stiffness attenuation measuring unit (63) will be described.

[0181] (3-1-4-1. Configuration of stiffness damping measuring unit (63)) The configuration of the stiffness damping measuring unit (63) will be described with reference to Fig. 8. As shown in Fig. 8, the stiffness damping measuring unit (63) has a frequency correcting unit (66) and a stiffness damping measurement executing unit (67).

[0182] The frequency correction unit (66) corrects the frequency f (28c) using the temperature T (28e), the pressure P (28t), and the density measurement correction coefficient (28m), and outputs the corrected frequency (225). The frequency correction unit (66) also performs the same operation as the frequency correction in density measurement. That is, the frequency correction unit (66) performs correction so that the above formula (9) is satisfied.

[0183] The stiffness damping measurement execution unit (67) executes stiffness and damping measurements. The stiffness damping measurement execution unit (67) switches the drive gain selector (21f) by drive gain selection (240) to use a fixed drive gain (242). The stiffness damping measurement execution unit (67) varies the amplitude S1 (27d), the amplitude S2 (27e), and the drive current (27a) according to the fixed drive gain (242). The stiffness damping measurement execution unit (67) calculates the mass Mc (221d), stiffness Kc (221e), damping Dc (221f), and Q value Qc (221g) according to the signal at the time of variation and the corrected frequency (225). The stiffness damping measurement execution unit (67) also corrects the results according to the density ρ (28b) and the temperature T (28e). The stiffness damping measurement execution unit (67) also stores the diagnosis information in the stiffness damping diagnosis result (221). Moreover, the stiffness damping measurement execution unit 67 sets the date and time 28x of the parameter 28 to the diagnosis date and time 221x. Moreover, the stiffness damping measurement execution unit 67 sets the conversion unit drive time 28y of the parameter 28 to the drive time 221y. Moreover, the stiffness damping measurement execution unit 67 sets the integrated flow rate 28z of the parameter 28 to the integrated flow rate 221z.

[0184] (3-1-4-2. Signal waveform during operation of stiffness damping measuring unit (63)) The signal waveforms during operation of the stiffness damping measurement unit (63) will be described with reference to FIG. 9. "Switch" shown in FIG. 9 indicates the selection of the drive gain selector (21f). In normal measurement, it is "AGC", i.e., the AGC drive gain (241). The stiffness damping measurement execution unit (67) changes the drive gain selection (240) to "Fixed Drive Gain", i.e., the fixed drive gain (242). While the fixed drive gain (242) is selected, the stiffness damping measurement execution unit (67) averages the corrected frequency (225) and the temperature T (28e) to obtain the corrected frequency fc and temperature Tc.

[0185] 9, "DG" indicates a drive gain. Also, "Amplitude" indicates the amplitude of the upstream signal S1 (13a) or the downstream signal S2 (14a). In normal measurement, the AGC drive gain (241) is controlled by the amplitude control unit (21b) of the Coriolis mass flowmeter (1) so that the amplitude of the upstream signal S1 (13a) becomes the amplitude target value (27c).

[0186] The stiffness damping measurement execution unit (67) changes the drive gain selection (240) and selects the fixed drive gain (242). Here, the amplitude is reduced by setting the fixed drive gain (242) to DG1, which is a value smaller than the AGC drive gain (241). The stiffness damping measurement execution unit (67) presets amplitude thresholds ATH1 and ATH2 and compares them with the amplitude of the upstream signal S1 (13a). Then, the stiffness damping measurement execution unit (67) stores the amplitude Ax1 and the time t1 when the amplitude crosses the amplitude threshold ATH1. Here, the variable x indicates the signal number. The stiffness damping measurement execution unit (67) also stores the amplitude Ax2 and the time t2 when the amplitude of the upstream signal S1 (13a) crosses the amplitude threshold ATH2.

[0187] Here, the amplitude increases by setting the fixed drive gain (242) to DG2, which is a value greater than the AGC drive gain (241). The stiffness damping measurement execution unit (67) stores the amplitude Ax3 and the time t3 when the amplitude of the upstream signal S1 (13a) crosses the amplitude threshold ATH2. It also stores the amplitude Ax4 and the time t4 when the amplitude of the upstream signal S1 (13a) crosses the amplitude threshold ATH1.

[0188] The stiffness damping measurement execution unit (67) changes the drive gain selection (240) to the AGC drive gain (241). At this time, the stiffness damping measurement execution unit (67) sets the average value of the gain when the fixed drive gain (242) is DG1 to the gain GC1. Also, the stiffness damping measurement execution unit (67) sets the average value of the gain when the fixed drive gain (242) is DG2 to the gain GC2. Furthermore, the stiffness damping measurement execution unit (67) calculates the increase / decrease rates αx1 and αx2 from the above equations (35) and (36).

[0189] In Fig. 9, the amplitude is lowered and then increased, but it can also be set to increase and then lower. Also, by setting the drive gain, it is possible to change the amplitude around the amplitude during AGC. Also, fluctuations can be suppressed by repeatedly raising and lowering the amplitude and taking the average.

[0190] (3-1-5. Stiffness damping initialization process) The stiffness attenuation initialization process performed by the stiffness attenuation initialization unit 64 of the stiffness attenuation diagnosis unit 61 will be described with reference to Fig. 10. Fig. 10 is a diagram showing an example of stiffness attenuation diagnosis process 3 according to the embodiment.

[0191] The stiffness damping initialization unit (64) sets an initial value to the stiffness damping diagnosis set value (222) as shown below. That is, the stiffness damping initialization unit (64) stores the value of stiffness Kc (221e) in initial stiffness Kc0 (222e), stores the value of damping Dc (221f) in initial damping Dc0 (222f), stores the value of Q value Qc (221g) in initial Q value Qc0 (222g), stores the value of diagnosis date and time (221x) in initial date and time (222x), stores the value of drive time (221y) in initial drive time (222y), and stores the value of integrated flow rate (221z) in initial integrated flow rate (222z). In addition, the stiffness damping initialization unit (64) resets the initial value acquisition command (222u).

[0192] The stiffness damping initialization unit (64) initializes the stiffness damping diagnosis result (221) as shown below. That is, the stiffness damping initialization unit (64) stores a value of 1.0 in the stiffness change rate aKc (221a), stores a value of 1.0 in the damping change rate aDc (221b), and stores a value of 1.0 in the Q value change rate aQc (221c). The stiffness damping initialization unit (64) also resets the stiffness change rate abnormality (221m), the damping change rate abnormality (221n), the Q value change rate abnormality (221o), the corrosion abnormality (221p), and the adhesion abnormality (221q). The stiffness damping initialization unit (64) also sets the initialization flag (221t) and the update flag (221s).

[0193] The stiffness damping initialization unit (64) resets the stiffness damping diagnosis execution signal (230) and sets the stiffness damping diagnosis completion signal (231).

[0194] (3-1-6. Stiffness attenuation judgment process) The stiffness attenuation determination process by the stiffness attenuation determination unit (65) of the stiffness attenuation diagnosis unit (61) will be described with reference to Fig. 11. Fig. 11 is a diagram showing an example of stiffness attenuation diagnosis process 4 according to the embodiment. As shown in Fig. 11, the stiffness attenuation determination unit (65) has a change ratio calculation unit (68) and a change ratio comparison unit (69).

[0195] The stiffness attenuation determination unit (65) calculates the rate of change. At this time, the change ratio calculation unit (68) calculates the rate of change from the stiffness attenuation diagnosis result (221) and the stiffness attenuation diagnosis setting value (222) and stores the result in the stiffness attenuation diagnosis result (221). At this time, the change ratio calculation unit (68) calculates the stiffness change rate aKc (221a) from the stiffness Kc (221e) and the initial stiffness Kc0 (222e) using the above formula (43). The change ratio calculation unit (68) also calculates the damping change rate aDc (221b) from the damping Dc (221f) and the initial damping Dc0 (222f) using the above formula (44). The change ratio calculation unit (68) also calculates the Q value change rate aQc (221c) from the Q value Qc (221g) and the initial Q value Qc0 (222g) using the above formula (45).

[0196] The stiffness damping determination unit (65) compares the rate of change with the allowable value and sets an abnormality determination value. At this time, the change ratio comparison unit (69) uses the above formula (46) to compare the stiffness change rate aKc (221a) with the stiffness change rate allowable value (222m) and sets stiffness change rate abnormality (221m). The change ratio comparison unit (69) also uses the above formula (47) to compare the damping change rate aDc (221b) with the damping change rate allowable value (222n) and sets damping change rate abnormality (221n). The change ratio comparison unit (69) also uses the above formula (48) to compare the Q value change rate aQc (221c) with the Q value change rate allowable value (222o) and sets the Q value change rate abnormality (221o). The change ratio comparison unit (69) also performs corrosion determination using the above formula (49) and sets corrosion abnormality (221p). Moreover, the change ratio comparison section (69) performs adhesion determination using the above formula (50) and sets adhesion abnormality (221q).

[0197] The stiffness attenuation determination unit (65) resets the initialization flag (221t) and sets the update flag (221s). The stiffness attenuation determination unit (65) also resets the stiffness attenuation diagnosis execution signal (230) and sets the stiffness attenuation diagnosis completion signal (231).

[0198] (3-2. Thickness Diagnosis Processing) 12 to 17 and equations, the wall thickness diagnosis process executed by the wall thickness diagnosis unit (70) of the diagnosis device (2) according to the embodiment will be described. In the following, after explaining the theoretical equation of the wall thickness diagnosis process, the whole wall thickness diagnosis process, the initialization determination process, the wall thickness diagnosis initialization process, the wall thickness calculation process, the wall thickness change initialization process, and the wall thickness change determination process will be described in this order.

[0199] (3-2-1. Theoretical formula for thickness diagnosis processing) The theoretical formula for the stiffness damping diagnostic process will be described below. First, the second moment of area I of a cantilever beam whose cross section is a tube is expressed by the following formula (51).

[0200]

number

[0201] The stiffness (spring constant) K is given by the following equation (52).

[0202]

number

[0203] In the above formula (52), E is Young's modulus and l is the length of the cantilever. The above formula (52) shows that the inner diameter and rigidity change due to corrosion. Therefore, the above formula (52) cannot be used to evaluate other phenomena such as adhesion.

[0204] From the above formula (52), the relationship between the stiffness change rate aKc (221a) and the change in inner diameter is given by the following formula (53): In the following formula (53), stiffness Kc0 indicates the initial stiffness Kc0 (222e), and stiffness Kc indicates the stiffness Kc (221e).

[0205]

number

[0206] The inner diameter dc2 is given by the following equation (54).

[0207]

number

[0208] Here, the vibrating tube of the Coriolis mass flowmeter (1) can be said to be a cantilever beam, but it has a complex shape. Therefore, although it cannot be expressed by the above formula (51), the dependency on the inner diameter and the outer diameter is considered to be the same. Also, by calculating the inner diameter dcc (321a) using the correction formula expressed by the following formula (55), the error can be suppressed.

[0209]

number

[0210] In the above formula (55), the coefficient d0 indicates the initial inner diameter d0 (322a). The correction coefficient Cdc1 (322f) is a value that depends on the characteristics of the detection unit (10). The correction equation for the inner diameter dcc (321a) may be a higher-order equation instead of a linear equation. In this case, the correction coefficient Cdc1 (322f) depends on the detector, and is therefore set in advance for each detector. There are several methods, such as actually corroding the oscillating tube and calculating the effect of corrosion by simulation.

[0211] The thickness tcc (321b) is given by the following formula (56).

[0212]

number

[0213] The change in thickness dtc (321c) is given by the following formula (57).

[0214]

number

[0215] The wall thickness change rate rtc (321d) from the initial state is given by the following formula (58).

[0216]

number

[0217] A thickness diagnosis is performed from the change in thickness. Here, it is determined whether the absolute value of the difference between the inside diameter dcc (321a) and the initial inside diameter d0 (322a) is greater than the inside diameter tolerance (322i). In this case, the conditional formula is the following formula (59). In the following formula (59), the coefficient dcclim indicates the inside diameter tolerance (322i). If the absolute value is large, an inside diameter abnormality (321i) is set. There is also a method of determining the difference by setting an upper and lower limit.

[0218]

number

[0219] It is determined whether the absolute value of the difference between the thickness tcc (321b) and the initial thickness is greater than the thickness tolerance (322j). In this case, the conditional formula is the following formula (60). In the following formula (60), the coefficient tcclim indicates the thickness tolerance (322j). If the absolute value is large, a thickness abnormality (321j) is set. There is also a method of determining by setting an upper and lower limit.

[0220]

number

[0221] It is determined whether the absolute value of the thickness change dtc (321c) is greater than the thickness change tolerance (322k). In this case, the conditional formula is the following formula (61). In the following formula (61), the coefficient dtclim indicates the thickness change tolerance (322k). If the absolute value is large, a thickness change abnormality (321k) is set. Note that there is also a method of determining by setting upper and lower limits.

[0222]

number

[0223] It is determined whether the thickness change rate rtc (321d) is greater than the thickness change rate tolerance (322l). In this case, the conditional formula is the following formula (62). In the following formula (62), the coefficient rtclim indicates the thickness change rate tolerance (322l). If the change rate is large, a thickness change rate abnormality (321l) is set. If there is no change, the thickness change rate rtc (321d) becomes the value 1.0. There is also a method of determining by setting upper and lower limits.

[0224]

number

[0225] Consider a vibration tube with a circular cross section, outer diameter D, and inner diameter d. If the density of the vibration tube is ρu, the length of the vibration tube is lu, and the number of vibration tubes is m, then the mass Mu of the vibration tube itself is expressed by the following equation (63).

[0226]

number

[0227] The wall thickness t of the vibrating tube is given by the following equation (64).

[0228]

number

[0229] The internal volume V of the vibrating tube is given by the following equation (65).

[0230]

number

[0231] Moreover, the coefficient Cd is defined as shown in the following equation (66).

[0232]

number

[0233] Here, in the above formula (66), the first term Cda is a term due to the mass and internal volume of the vibration tube, and depends on the cross-sectional shape and material. Also, the second term Cdb is a term due to the mass Mu of the accessory and the internal volume of the vibration tube. In other words, the above formula (66) indicates that the heavier the accessory, the larger Cd becomes.

[0234] In a Coriolis mass flowmeter (1), the amplitude becomes larger toward the tip, the kinetic energy varies depending on the distance from the fixed point, and the farther the mass is located, the greater the impact on the vibration. In order to discuss this accurately, it is necessary to consider the equivalent mass. The first term Cda of the coefficient Cd is not affected by position as long as the cross-sectional shape of the vibrating tube does not change. The second term Cdb is affected by position. The vibrating tube length lu and the mass Md of accessories are values ​​that take into account the equivalent mass.

[0235] Consider a case where the inside diameter d of the oscillating tube increases uniformly due to corrosion or other reasons to become an inside diameter dc. The coefficient Cdc after the change is expressed by the following equation (67).

[0236]

number

[0237] If the vibration conditions of the entire Coriolis mass flowmeter do not change, there is no change in the equivalent mass, and no change occurs in the vibration tube length lu and the mass Md of the accessories.

[0238] The relationship between the coefficient Cdc and the stiffness Kc after the change is given by the following equation (68): In the following equation (68), the frequency at which a material with density ρa is measured is denoted as fac.

[0239]

number

[0240] The internal volume Vc of the vibrating tube is calculated from the inner diameter dc, as shown in the following equation (69).

[0241]

number

[0242] If the inner diameter changes, the measurement error can be eliminated by performing calibration again and determining the coefficient Cdc and frequency fac.

[0243] The relationship between the change in density measurement coefficient and the wall thickness and rigidity is shown below. The changed inner diameter dc of the vibration tube is found from the above formulas (66) and (67), resulting in the following formula (70). In the following formula (70), the density measurement coefficient Cd in the initial state is set to the initial density measurement coefficient Cd0. Also, the inner diameter d of the vibration tube in the initial state is set to the initial vibration tube inner diameter d0. Also, it is assumed that the vibration tube density ρu does not change. By using the following formula (70), the changed inner diameter dc of the vibration tube can be calculated from the changed density measurement coefficient Cdc and the initial density measurement coefficient Cd0.

[0244]

number

[0245] The wall thickness tc of the vibrating tube is calculated using the following equation (71).

[0246]

number

[0247] The change in thickness dt is expressed by the following equation (72).

[0248]

number

[0249] The wall thickness change rate rt is given by the following equation (73).

[0250]

number

[0251] Moreover, the density measurement coefficient fa in the initial state is set as the initial density measurement coefficient fa0. The stiffness change rate aK of the vibrating tube from the initial state can be calculated from the above equations (14) and (68) by the following equation (74). In the following equation (74), stiffness K0 indicates the initial stiffness.

[0252]

number

[0253] (3-2-2. Overall processing of thickness diagnosis) The entire stiffness attenuation diagnosis process will be described with reference to Fig. 12. Fig. 12 is a diagram showing an example of the entire thickness diagnosis process according to the embodiment. The configuration of the thickness diagnosis unit (70) of the diagnosis device (2) will be described below.

[0254] 12, the wall thickness diagnosis unit (70) is a part of the diagnosis control unit (60), and estimates a wall thickness change by using an equation for the moment of inertia of area from the stiffness damping diagnosis result (221). The wall thickness diagnosis unit (70) also has an initialization determination unit (71), a wall thickness diagnosis initialization unit (72), a wall thickness calculation unit (73), a wall thickness change initialization unit (74), and a wall thickness change determination unit (75), which respectively execute an initialization determination process, a wall thickness diagnosis initialization process, a wall thickness calculation process, a wall thickness change initialization process, and a wall thickness change determination process.

[0255] The wall thickness diagnosis unit (70) executes processing when the stiffness damping diagnosis completion signal (231) is set. First, the initialization determination unit (71) determines whether or not an initialization operation should be performed based on the wall thickness diagnosis set value (322), the stiffness damping diagnosis result (221), and the stiffness damping diagnosis completion signal (231). The initialization determination unit (71) also sets the initialization signal (306), the diagnosis initialization signal (307), or the diagnosis execution signal (308).

[0256] At the first execution, an initialization signal (306) is set, and the thickness diagnosis initialization unit (72) executes the process. If it is necessary to reset the reference data, a diagnosis initialization signal (307) is set, and the thickness calculation unit (73) and the thickness change initialization unit (74) execute the process. If it is desired to set the current state as the initial value, resetting is performed. At the time of normal diagnosis, a diagnosis execution signal (308) is set, and the thickness calculation unit (73) and the thickness change determination unit (75) execute the process.

[0257] (3-2-3. Initialization Judgment Process) The initialization determination process by the initialization determination unit (71) of the wall thickness diagnosis unit (70) will be described with reference to FIG. 13. FIG. 13 is a diagram showing an example of wall thickness diagnosis process 1 according to the embodiment. As shown in FIG. 13, the initialization determination unit (71) executes the process when the stiffness attenuation diagnosis completion signal (231) is set. The initialization determination unit (71) outputs an initialization signal (306), a diagnosis initialization signal (307), and a diagnosis execution signal (308) based on the initial inner diameter d0 (322a), the initialization execution command (322u), and the initial date and time (322x) as the wall thickness diagnosis set value (322), and the initialization flag (221t) as the stiffness attenuation diagnosis result (221). The flow of the initialization determination process will be described later in [5. Flow of each process of the diagnosis device (2)].

[0258] (3-2-4. Thickness diagnosis initialization process) The wall thickness diagnosis initialization process performed by the wall thickness diagnosis initialization unit (72) of the wall thickness diagnosis section (70) will be described with reference to Fig. 14. Fig. 14 is a diagram showing an example of the wall thickness diagnosis process 2 according to the embodiment. As shown in Fig. 14, the wall thickness diagnosis initialization unit (72) has a wall thickness calculation unit (76).

[0259] The wall thickness diagnosis initialization unit (72) sets an initial value for the wall thickness diagnosis set value (322) as shown below. That is, the wall thickness diagnosis initialization unit (72) substitutes the value of the diagnosis date and time (221x) for the initial date and time (322x), the value of the drive time (221y) for the initial drive time (322y), the value of the integrated flow rate (221z) for the initial integrated flow rate (322z), and the value of the vibration pipe inner diameter d (303c) for the initial inner diameter d0 (322a). In addition, the wall thickness diagnosis initialization unit (72) resets the initialization execution command (322u).

[0260] The wall thickness diagnosis initialization unit (72) initializes the wall thickness diagnosis result (321) as follows: That is, the wall thickness diagnosis initialization unit (72) substitutes the value of the diagnosis date and time (221x) for the diagnosis date and time (321x), the value of the drive time (221y) for the drive time (321y), the value of the integrated flow rate (221z) for the integrated flow rate (321z), the value of the stiffness change rate aKc (221a) for the stiffness change rate aKc (321e), the value of the damping change rate aDc (221b) for the damping change rate aDc (321f), the value of the Q value change rate aQc (221c) for the Q value change rate aQc (321g), and the value of the vibration pipe inner diameter d (303c) for the inner diameter dcc (321a). The wall thickness diagnosis initialization unit (72) also calculates the initial wall thickness using the wall thickness calculation unit (76) and sets the wall thickness to the wall thickness tcc (321b). The wall thickness diagnosis initialization unit (72) also substitutes the inner diameter dcc (321a) and the vibration tube outer diameter D (303a) into the formula (56) to obtain the wall thickness tcc (321b). The wall thickness diagnosis initialization unit (72) also sets the thickness change dtc (321c) to a value of 0.0, sets the thickness change rate rtc (321d) to a value of 0.0, resets the inner diameter abnormality (321i), resets the wall thickness abnormality (321j), resets the wall thickness change abnormality (321k), and resets the wall thickness change rate abnormality (321l). The initialization flag (321t) is also set to indicate that the wall thickness diagnosis result (321) has been initialized. Also, the update flag (321s) is set to indicate that the thickness diagnosis result (321) has been updated.

[0261] The wall thickness diagnosis initialization unit 72 resets the stiffness attenuation diagnosis completion signal 231 to prepare for the next stiffness measurement, and also sets the wall thickness diagnosis completion signal 331 to indicate that the wall thickness diagnosis process has ended.

[0262] (3-2-5. Thickness calculation processing) The thickness calculation process by the thickness calculation unit (73) of the thickness diagnosis unit (70) will be described with reference to Fig. 15. Fig. 15 is a diagram showing an example of the thickness diagnosis process 3 according to the embodiment. As shown in Fig. 15, the thickness calculation unit (73) has a thickness change rate calculation unit (78).

[0263] The thickness calculation unit (73) calculates the thickness change rate by the thickness change rate calculation unit (78) as shown below, and sets it in the thickness diagnosis result (321). That is, the thickness calculation unit (73) calculates the inner diameter dcc (321a) by the above formulas (54) and (55). At this time, the thickness calculation unit (73) uses the vibration tube outer diameter D (303a), the vibration tube inner diameter d (303c), the initial inner diameter d0 (322a), and the stiffness change rate aKc (221a). The thickness calculation unit (73) also calculates the thickness tcc (321b) by the above formula (56). At this time, the thickness calculation unit (73) uses the vibration tube outer diameter D (303a) and the inner diameter dcc (321a). The thickness calculation unit (73) also calculates the thickness change dtc (321c) by the above formula (57). At this time, the wall thickness calculation unit (73) uses the initial inner diameter d0 (322a) and the inner diameter dcc (321a). The wall thickness calculation unit (73) also obtains the wall thickness change rate rtc (321d) by the above formula (58). At this time, the wall thickness calculation unit (73) uses the vibration tube outer diameter D (303a), the initial inner diameter d0 (322a), and the inner diameter dcc (321a).

[0264] The thickness calculation unit (73) sets the stiffness attenuation diagnosis result (221) to the thickness diagnosis result (321) as shown below. That is, the thickness calculation unit (73) assigns the value of the stiffness change rate aKc (221a) to the stiffness change rate aKc (321e), assigns the value of the damping change rate aDc (221b) to the damping change rate aDc (321f), assigns the value of the Q value change rate aQc (221c) to the Q value change rate aQc (321g), assigns the value of the diagnosis date and time (221x) to the diagnosis date and time (321x), assigns the value of the drive time (221y) to the drive time (321y), and assigns the value of the integrated flow rate (221z) to the integrated flow rate (321z).

[0265] (3-2-6. Initialization process for thickness change) The thickness change initialization process performed by the thickness change initialization unit (74) of the thickness diagnosis unit (70) will be described with reference to Fig. 16. Fig. 16 is a diagram showing an example of the thickness diagnosis process 4 according to the embodiment.

[0266] The thickness change initialization unit (74) sets an initial value of the thickness diagnosis set value (322) as follows. That is, the thickness change initialization unit (74) substitutes the value of the diagnosis date and time (221x) for the initial date and time (322x), the value of the drive time (221y) for the initial drive time (322y), the value of the integrated flow rate (221z) for the initial integrated flow rate (322z), and the value of the inside diameter dcc (321a) for the initial inside diameter d0 (322a). The thickness change initialization unit (74) also resets the initialization execution command (322u).

[0267] The thickness change initialization unit (74) initializes the thickness diagnosis result (321) as shown below. The thickness change initialization unit (74) does not initialize the inner diameter dcc (321a) and the thickness tcc (321b), but inherits the thickness diagnosis result (321). The thickness change initialization unit (74) also sets the thickness change dtc (321c) to a numerical value of 0.0, and sets the thickness change rate rtc (321d) to a numerical value of 0.0. The thickness change initialization unit (74) also resets the inner diameter abnormality (321i), the thickness abnormality (321j), the thickness change abnormality (321k), and the thickness change rate abnormality (321l). The thickness change initialization unit (74) also sets an initialization flag (321t) to indicate that the thickness diagnosis result (321) has been initialized. In addition, the thickness change initialization unit 74 sets an update flag 321s to indicate that the thickness diagnosis result 321 has been updated.

[0268] The thickness change initialization unit 74 resets the stiffness attenuation diagnosis completion signal 231 to prepare for the next stiffness measurement, and also sets the thickness diagnosis completion signal 331 to indicate that the thickness diagnosis process has ended.

[0269] (3-2-7. Thickness change determination process) The thickness change determination process by the thickness change determination unit (75) of the thickness diagnosis section (70) will be described with reference to Fig. 17. Fig. 17 is a diagram showing an example of the thickness diagnosis process 5 according to the embodiment. As shown in Fig. 17, the thickness change determination unit (75) has an abnormality determination unit (79).

[0270] As described below, the thickness change determination unit (75) uses the abnormality determination unit (79) to compare the thickness diagnosis result (321) with the thickness diagnosis set value (322) and set an abnormality determination value in the thickness diagnosis result (321). That is, the thickness change determination unit (75) compares the inside diameter dcc (321a) with the inside diameter allowable value (322i). If the difference is outside the allowable value, the thickness change determination unit (75) sets the inside diameter abnormality (321i). On the other hand, if the difference is within the allowable value, the thickness change determination unit (75) resets the inside diameter abnormality (321i). In the case of corrosion, the inside diameter dcc (321a) becomes large. In addition, the thickness change determination unit (75) compares the thickness tcc (321b) with the inside thickness allowable value (322j). At this time, if the difference is outside the allowable range, the thickness change determination unit (75) sets the thickness abnormality (321j). On the other hand, if the difference is within the allowable range, the thickness change determination unit (75) resets the thickness abnormality (321j). In the case of corrosion, the thickness tcc (321b) becomes smaller.

[0271] The thickness change determination unit (75) also compares the thickness change dtc (321c) with the thickness change allowable value (322k). If the thickness change dtc is outside the allowable value, the thickness change determination unit (75) sets a thickness change anomaly (321k). On the other hand, if the thickness change dtc is within the allowable value, the thickness change anomaly (321k) is reset. In the case of corrosion, the thickness change dtc (321c) becomes negative. The thickness change determination unit (75) also compares the thickness change rate rtc (321d) with the thickness change rate allowable value (322l). If the thickness change dtc is outside the allowable value, the thickness change determination unit (75) sets a thickness change rate anomaly (321l). On the other hand, if the thickness change dtc is within the allowable value, the thickness change determination unit (75) resets the thickness change rate anomaly (321l). In the case of corrosion, the wall thickness change rate rtc (321d) is smaller than 1. The wall thickness change determination unit (75) can also perform a determination process using one or more of the four parameters for the abnormality information in the wall thickness diagnosis result (321) described above.

[0272] The thickness change determination unit 75 resets the initialization flag 321t to indicate that the thickness diagnosis result 321 has not been initialized, and sets the update flag 321s to indicate that the thickness diagnosis result 321 has been updated.

[0273] The thickness change determination unit 75 resets the stiffness attenuation diagnosis completion signal 231 to prepare for the next stiffness measurement, and also sets the thickness diagnosis completion signal 331 to indicate that the thickness diagnosis process has ended.

[0274] (3-3. Density error diagnosis and simple correction process) 18 to 22 and equations, the density error diagnosis and simple correction process executed by the density error diagnosis simple correction unit (80) of the diagnosis device (2) according to the embodiment will be described. Below, after explaining the theoretical equation of the density error diagnosis and simple correction process, the overall density error diagnosis and simple correction process, the initialization determination process, the density initialization process, the rigidity thickness initialization process, and the density correction coefficient update process will be described in that order.

[0275] (3-3-1. Theoretical formula for density error diagnosis and simple correction processing) The theoretical formula for density error diagnosis and simple correction processing will be described below. The density error diagnosis and simple correction unit (80) of the diagnosis device (2) diagnoses density error from stiffness changes and wall thickness changes, and performs simple correction of the density measurement coefficient, as shown below.

[0276] The density measurement coefficient before the change is the initial coefficient Cdc0 (422a) and the initial coefficient fac0 (422b), the vibration tube inner diameter before the change is the initial inner diameter dc0 (422c), the stiffness change rate before the change is the initial stiffness change rate aKc0 (422d), the density measurement coefficient after the change is the density measurement coefficient Cdcc (421a) and the density measurement coefficient facc (421b), and the vibration tube inner diameter after the change is the inner diameter dcc (321a). In addition, the vibration tube density ρu (303b) is assumed to remain unchanged, and the stiffness change rate after the change is the stiffness change rate aKc (321e). The change in the vibration tube inner diameter is obtained from the change in the density measurement coefficient from the above formulas (66) and (67). At this time, by using the linearly corrected inner diameter dcc (321a), the error caused by using the formula for the second moment of area can be suppressed.

[0277] The inside diameter dcc (321a) of the vibration tube after the change is expressed by the following formula (75).

[0278]

number

[0279] By expanding the equation and finding the density measurement coefficient Cdcc (421a), we obtain the following equation (76).

[0280]

number

[0281] The change in stiffness is expressed by the following equation (77) based on the above equations (14) and (68).

[0282]

number

[0283] By expanding the equation and finding the density measurement coefficient facc(421b), we obtain the following equation (78).

[0284]

number

[0285] The density measurement coefficient Cdcc (421a) is set to the density measurement coefficient Cd (28k), and the density measurement coefficient facc (421b) is set to the density measurement coefficient fa (28l), and simple correction is performed.

[0286] When the coefficient change rate aCdc (421c) is calculated from the initial coefficient Cdc0 (422a) and the density measurement coefficient Cdcc (421a), the following formula (79) is obtained.

[0287]

number

[0288] The coefficient change rate afac (421d) is calculated from the initial coefficient fac0 (422b) and the density measurement coefficient facc (421b) as shown in the following equation (80).

[0289]

number

[0290] Calculate the density error that occurs due to changes in the density measurement coefficients. Let the initial density measurement coefficients be Cdc0 and fac0. Also, let the current density measurement coefficients be Cdc and fac. From equation (13) above, when measuring a material with a measurement target density ρt (422 g), the frequency fd is given by equation (81) below.

[0291]

number

[0292] Here, the density error Δρd expressed by the following equation (82) occurs when the density measurement coefficients are not updated and measurement is performed with the initial density measurement coefficients Cdc0 and fac0.

[0293]

number

[0294] The density error Δρe calculated using the density measurement coefficient Cdcc (421a) and the density measurement coefficient facc (421b) is given by the following equation (83).

[0295]

number

[0296] Calculate the density fluctuation caused by replacing the density measurement coefficient. From the density measurement coefficient Cdcc (421a) and the density measurement coefficient facc (421b) obtained by the above equations (76) and (78), calculate the frequency fc when measuring a material with the measurement target density ρt (422g), and obtain the following equation (84).

[0297]

number

[0298] When the density fluctuation Δρ (421e) is calculated from the density measurement coefficient Cd (28k) before the change, the density measurement coefficient fa (28l), and the frequency fc, the following equation (85) is obtained.

[0299]

number

[0300] Changing the density measurement coefficient creates discontinuities in the density measurement results. If the density fluctuation Δρ (421e) is within the allowable range, there is also the option of prioritizing the continuity of the measurement values. The density fluctuation allowable value (422h) is set to ρlim and compared with the absolute value of the density fluctuation Δρ (421e). Small fluctuations are suppressed by determining whether or not the density measurement coefficient can be replaced. In this case, the conditional formula is the following formula (86).

[0301]

number

[0302] It is possible to set an alarm when the density measurement coefficient is replaced.

[0303] Calculating the density error Δρ0 (421f) from density calibration results in the following equation (87). The density measurement coefficients during density calibration are the initial coefficient Cdc0 (422a) and the initial coefficient fac0 (422b). The frequency fc calculated using equation (84) above is used.

[0304]

number

[0305] When the absolute value of the density error Δρ0 (421f) becomes equal to or greater than the density error warning value (422r), a density diagnosis abnormality (421r) is set. At this time, the condition formula is the following formula (88).

[0306]

number

[0307] In the above formula (88), the error warning value ρ0lim indicates the density error warning value (422r). By indicating a density diagnosis abnormality (421r), recalibration is prompted.

[0308] The density error diagnosis and simple correction process described above includes a diagnosis process that monitors density error and issues an alarm, and a simple correction process that updates the density measurement coefficient to reduce the density error, and it is possible to use only one of these processes.

[0309] (3-3-2. Overall processing of density error diagnosis and simple correction) The overall process of density error diagnosis and simple correction processing will be described with reference to Fig. 18. Fig. 18 is a diagram showing an example of the overall process of density error diagnosis and simple correction processing according to the embodiment. The following describes the configuration of a density error diagnosis simple correction unit (80) of the diagnosis device (2).

[0310] As shown in Fig. 18, the density error diagnosis simple correction unit (80) is a part of the diagnosis control unit (60). The density error diagnosis simple correction unit (80) has an initialization determination unit (81), a density initialization unit (82), a rigidity thickness initialization unit (83), and a density correction coefficient update unit (84), which respectively execute an initialization determination process, a density initialization process, a rigidity thickness initialization process, and a density correction coefficient update process. The density error diagnosis simple correction unit (80) updates the density measurement coefficient Cd (28k) and the density measurement coefficient fa (28l) based on the thickness diagnosis result (321). Here, the density measurement coefficient Cd (28k) and the density measurement coefficient fa (28l) are included in the parameters (28) of the conversion unit (20).

[0311] The initialization determination unit (81) sets an initialization execution signal 1 (407), an initialization execution signal 2 (408), or an update execution signal (409). The density initialization unit (82) executes initialization processing when the density calibration unit (51) of the calibration device (3) is executed, and executes processing when the initialization execution signal 1 (407) is set. The rigidity thickness initialization unit (83) executes initialization processing when the thickness diagnosis unit (70) is executed, and executes processing when the initialization execution signal 2 (408) is set. The density correction coefficient update unit (84) updates the flow rate measurement coefficient, and executes processing when the update execution signal (409) is set.

[0312] (3-3-3. Initialization Judgment Process) The initialization determination process by the initialization determination unit (81) of the density error diagnosis simple correction unit (80) will be described with reference to FIG. 19. FIG. 19 is a diagram showing an example of density error diagnosis and simple correction process 1 according to the embodiment. As shown in FIG. 19, the initialization determination unit (81) executes the process when the density calibration completion signal (122) or the thickness diagnosis completion signal (331) is set. The initialization determination unit (81) also outputs an initialization execution signal 1 (407), an initialization execution signal 2 (408), and an update execution signal (409) based on an initialization flag (321t) as the thickness diagnosis result (321) and an initial date and time (422x) and an initialization execution command (422u) as the density diagnosis set value (422). The flow of the initialization determination process will be described later in [5. Flow of each process of the diagnosis device (2)].

[0313] (3-3-4. Density initialization process) The density initialization process by the density initialization unit (82) of the density error diagnosis simple correction unit (80) will be described with reference to Fig. 20. Fig. 20 is a diagram showing an example of density error diagnosis and simple correction process 2 according to the embodiment. As shown in Fig. 20, the density initialization unit (82) has an inner diameter stiffness selection unit (85).

[0314] The density initialization unit (82) initializes the density diagnosis set value (422) by the inner diameter stiffness selection unit (85) as shown below. That is, the density initialization unit (82) sets an initial change rate. At this time, if the diagnosis date and time (321x) has not been set, the density initialization unit (82) sets the vibration pipe inner diameter d (303c) to the initial inner diameter dc0 (422c). In addition, the density initialization unit (82) sets the initial stiffness change rate aKc0 (422d) to a numerical value of 1.0. On the other hand, if the diagnosis date and time (321x) has been set, the density initialization unit (82) sets the inner diameter dcc (321a) to the initial inner diameter dc0 (422c). In addition, the density initialization unit (82) sets the stiffness change rate aKc (321e) to the initial stiffness change rate aKc0 (422d).

[0315] The density initialization unit 82 sets the density measurement coefficient Cd (28k) to the initial coefficient Cdc0 (422a), sets the density measurement coefficient fa (28l) to the initial coefficient fac0 (422b), sets the flow calibration date and time (28h) to the initial date and time (422x), sets the flow calibration drive time (28i) to the initial drive time (422y), and sets the flow calibration integrated flow rate (28j) to the initial integrated flow rate (422z). In addition, the density initialization unit 82 sets an initialization execution command (422u) to perform initialization the next time stiffness damping diagnosis is performed.

[0316] The density initialization unit 82 initializes the density diagnosis result 421 as follows: That is, the density initialization unit 82 sets the density measurement coefficient Cd (28k) to the density measurement coefficient Cdcc (421a), sets the density measurement coefficient fa (28l) to the density measurement coefficient facc (421b), sets the coefficient change rate aCdc (421c) to a value of 1.0, sets the coefficient change rate afac (421d) to a value of 1.0, sets the density fluctuation Δρ (421e) to a value of 0.0, sets the density error Δρ0 (421f) to a value of 0.0, sets the flow rate calibration date and time (28h) to the correction date and time (421x), sets the flow rate calibration drive time (28i) to the drive time (421y), and sets the flow rate calibration integrated flow rate (28j) to the integrated flow rate (421z). The density initialization unit 82 also resets the density diagnosis abnormality 421r. The density initialization unit 82 also sets an initialization flag 421t to indicate that the density diagnosis result 421 has been initialized. The density initialization unit 82 also sets an update flag 421s to indicate that the density diagnosis result 421 has been updated.

[0317] The density initialization unit (82) resets the density calibration completion (122) and waits for the next density calibration to be performed, and also sets the density diagnosis completion (431) to indicate that the density error diagnosis and simple correction process has been performed.

[0318] (3-3-5. Initialization of rigidity and thickness) The rigidity thickness initialization process by the rigidity thickness initialization unit (83) of the density error diagnosis simple correction unit (80) will be described with reference to Fig. 21. Fig. 21 is a diagram showing an example of density error diagnosis and simple correction process 3 according to the embodiment.

[0319] The rigidity thickness initialization unit (83) initializes the density diagnosis set value (422) as follows: That is, the rigidity thickness initialization unit (83) sets the inner diameter dcc (321a) to the initial inner diameter dc0 (422c), the rigidity change rate aKc (321e) to the initial rigidity change rate aKc0 (422d), the diagnosis date and time (321x) to the initial date and time (422x), the drive time (321y) to the initial drive time (422y), and the integrated flow rate (321z) to the initial integrated flow rate (422z), as the thickness diagnosis result (321). The rigidity thickness initialization unit 83 also sets the density measurement coefficient Cd (28k) to an initial coefficient Cdc0 (422a) and sets the density measurement coefficient fa (28l) to an initial coefficient fac0 (422b) as the parameters 28. The rigidity thickness initialization unit 83 also resets the initialization execution command 422u and waits for an external initialization command.

[0320] The rigid thickness initialization unit 83 initializes the density diagnosis result 421 as follows: That is, the rigid thickness initialization unit 83 sets the diagnosis date and time 321x to the correction date and time 421x, sets the drive time 321y to the drive time 421y, sets the integrated flow rate 321z to the integrated flow rate 421z, sets the density measurement coefficient Cd (28k) to the density measurement coefficient Cdcc (421a), sets the density measurement coefficient fa (28l) to the density measurement coefficient facc (421b), sets the coefficient change rate aCdc (421c) to a value of 1.0, sets the coefficient change rate afac (421d) to a value of 1.0, sets the density fluctuation Δρ (421e) to a value of 0.0, and sets the density error Δρ0 (421f) to a value of 0.0. The rigid thickness initialization unit 83 also resets the density diagnosis abnormality 421r. The rigid thickness initialization unit 83 also sets an initialization flag 421t to indicate that the density diagnosis result 421 has been initialized. The rigid thickness initialization unit 83 also sets an update flag 421s to indicate that the density diagnosis result 421 has been updated.

[0321] The rigidity / thickness initialization unit 83 resets the thickness diagnosis completion signal 331 and waits for the next thickness diagnosis to be performed. The rigidity / thickness initialization unit 83 also sets the density diagnosis completion signal 431 to indicate that the density error diagnosis / simple correction process has been performed.

[0322] (3-3-6. Density correction coefficient update process) The density correction coefficient update process by the density correction coefficient update unit (84) of the density error diagnosis simple correction unit (80) will be described with reference to Fig. 22. Fig. 22 is a diagram showing an example of density error diagnosis and simple correction process 4 according to the embodiment. As shown in Fig. 22, the density correction coefficient calculation unit (86), density fluctuation comparator 1 (87), density correction coefficient setter (88), and density fluctuation comparator 2 (89) are included.

[0323] The density correction coefficient update unit 84 sets the measurement information of the density diagnosis result 421 as follows: That is, the density correction coefficient update unit 84 sets the diagnosis date and time 321x to the correction date and time 421x, sets the drive time 321y to the drive time 421y, and sets the integrated flow rate 321z to the integrated flow rate 421z.

[0324] The density correction coefficient update unit (84) calculates the density measurement coefficient, the coefficient change rate, the density fluctuation, and the density error by using the density correction coefficient calculation unit (86). That is, the density correction coefficient update unit (84) calculates the density measurement coefficient Cdcc (421a) by the above formula (76). At this time, the density correction coefficient update unit (84) uses the inside diameter dcc (321a), the initial inside diameter dc0 (422c), the initial coefficient Cdc0 (422a), and the vibration tube density ρu (303b). In addition, the density correction coefficient update unit (84) calculates the density measurement coefficient facc (421b) by the above formula (78). At this time, the density correction coefficient update unit (84) uses the stiffness change rate aKc (321e), the initial stiffness change rate aKc0 (422d), the density measurement coefficient Cdcc (421a), the initial coefficient Cdc0 (422a), the vibration tube density ρu (303b), and the initial coefficient fac0 (422b). The density correction coefficient update unit (84) also obtains the coefficient change rate aCdc (421c) by the above formula (79). At this time, the density correction coefficient update unit (84) uses the initial coefficient Cdc0 (422a) and the density measurement coefficient Cdcc (421a). The density correction coefficient update unit (84) also obtains the coefficient change rate afac (421d) by the above formula (80). At this time, the density correction coefficient update unit (84) uses the initial coefficient fac0 (422b) and the density measurement coefficient facc (421b). The density correction coefficient update unit (84) obtains the density fluctuation Δρ (421e) by the above formula (85). At this time, the density correction coefficient update unit (84) uses the density measurement coefficient fa (28l), the density measurement coefficient facc (421b), the density measurement coefficient Cd (28k), the density measurement coefficient Cdcc (421a), and the measurement object density ρt (422g). The density correction coefficient update unit (84) obtains the density error Δρ0 (421f) by the above formula (87). At this time, the density correction coefficient update unit (84) uses the initial coefficient fac0 (422b), the density measurement coefficient facc (421b), the initial coefficient Cdc0 (422a), the density measurement coefficient Cdcc (421a), and the measurement object density ρt (422g).

[0325] The density correction coefficient update unit (84) executes the following process using a density fluctuation comparator 1 (87). The density correction coefficient update unit (84) compares the absolute value of the density fluctuation Δρ (421e) with the density fluctuation tolerance (422h) using the above equation (86). At this time, if the absolute value of the density fluctuation Δρ (421e) is greater than the density fluctuation tolerance (422h), the density correction coefficient update unit (84) sets the density coefficient selection signal (404).

[0326] When the density coefficient selection signal (404) is set, the density correction coefficient update unit (84) sets the density measurement coefficients by the density correction coefficient setter (88). That is, the density correction coefficient update unit (84) sets the density measurement coefficient Cdcc (421a) to the density measurement coefficient Cd (28k) and sets the density measurement coefficient facc (421b) to the density measurement coefficient fa (28l).

[0327] The density correction coefficient updating unit (84) executes the following process using a density fluctuation comparator 2 (89). The density correction coefficient updating unit (84) compares the absolute value of the density error Δρ0 (421f) with the density error warning value (422r) using the above equation (88). At this time, if the absolute value of the density error Δρ0 (421f) is greater than the density error warning value (422r), the density correction coefficient updating unit (84) sets a density diagnosis abnormality (421r). On the other hand, if the absolute value of the density error Δρ0 (421f) is smaller than the density error warning value (422r), the density correction coefficient updating unit (84) resets it.

[0328] The density correction coefficient update unit 84 resets the initialization flag 421t to indicate that the density diagnosis result 421 has not been initialized, and sets the update flag 421s to indicate that the density diagnosis result 421 has been updated.

[0329] The density correction coefficient update unit 84 resets the thickness diagnosis completion signal 331 and waits for the next thickness diagnosis to be performed. The density correction coefficient update unit 84 also sets the density diagnosis completion signal 431 to indicate that the density error diagnosis and simple correction process have been performed.

[0330] (3-4. Flow rate error diagnosis and simple correction process) 23 to 27 and equations, the flow rate error diagnosis and simple correction process executed by the flow rate error diagnosis simple correction unit (90) of the diagnosis device (2) according to the embodiment will be described. Below, after explaining the theoretical equation of the flow rate error diagnosis and simple correction process, the entire flow rate error diagnosis and simple correction process, the initialization determination process, the flow rate initialization process, the rigidity thickness initialization process, and the flow rate correction coefficient update process will be described in this order.

[0331] (3-4-1. Theoretical formula for flow rate error diagnosis and simple correction processing) The theoretical formula for flow rate error diagnosis and simple correction processing is explained below. First, the flow rate correction coefficient fk(28u) included in the following equation (89) is calculated from the result of the wall thickness diagnosis, and the mass flow rate is simply corrected.

[0332]

number

[0333] In the above equation (89), the flow rate measurement coefficient Cq represents the flow rate measurement coefficient Cq (28f), the phase difference θ represents the phase difference θ (28d), the frequency f represents the frequency f (28c), the mass flow rate Qmc represents the mass flow rate Qm after simple correction (28a), and the value of the correction coefficient fk represents the flow rate correction coefficient fk (28u).

[0334] The flow rate measurement coefficient Cq in the mass flow rate measurement equation shown in equation (2) above includes the stiffness (spring constant) ks of the torsional vibration of the vibrating tube and the ratio of the resonance frequencies of bending vibration and torsional vibration. The stiffness change rate measured by diagnostic device (2) is the stiffness in the vibration direction, but is thought to fluctuate similarly to the stiffness of torsional vibration. Changes in wall thickness are related to changes in resonance frequency. Simple correction of the mass flow rate is possible by determining the correction coefficient fk from the rate of change obtained by diagnostic device (2).

[0335] In the diagnostic process described above, the changes in stiffness and thickness are obtained by the thickness diagnosis. In addition, the changes in the density measurement coefficient Cd and density measurement coefficient fa are obtained from the changes in stiffness and thickness. Here, the density measurement coefficient Cd and density measurement coefficient fa contain information about the vibrating tube. Therefore, by using the density measurement coefficient itself or the rate of change of the density measurement coefficient, simple correction of the mass flow rate is possible.

[0336] The calculation formula for the flow rate correction coefficient fkq using the stiffness change rate aKc (321e), the wall thickness change rate rtc (321d), the coefficient change rate aCdc (421c), and the coefficient change rate afac (421d) is shown in the following formula (90). Here, a simple correction is performed by substituting the flow rate correction coefficient fkq for the flow rate correction coefficient fk (28u).

[0337]

number

[0338] In the above equation (90), the coefficient Ckx indicates the flow rate correction coefficient Ckx(28v), and is a value that depends on the characteristics of the detection unit (10) of the Coriolis mass flowmeter (1). The correction equation for the flow rate correction coefficient fkq may be an approximate straight line or an approximate curve. The parameters and correction coefficients used are determined using multiple regression analysis, inference using AI (Artificial Intelligence), etc. The flow rate correction coefficient Ckx(28v) depends on the detector, and is therefore set in advance for each detector. Methods include actually corroding the vibrating tube and calculating the effects of corrosion through simulation.

[0339] In the above equation (90), the wall thickness change rate rtc (321d) is used, but the correction equation for the flow rate correction coefficient fkq can also be formed using any of the inner diameter dcc (321a), the wall thickness tcc (321b), or the wall thickness change dtc (321c).

[0340] In addition, conventional flow rate calibration requires actual flow of water, etc., and requires a separate device. Stiffness damping diagnosis does not require a special device to specify the reference flow rate, because it diagnoses with a constant oscillation feedback gain. Unlike flow rate calibration, which involves flowing a fluid, there is a high possibility of error.

[0341] When mass flow calibration is performed, the error that was corrected using the flow correction coefficient fk (28u) is absorbed by the flow measurement coefficient Cq (28f). Therefore, after mass flow calibration, it is necessary to set the flow correction coefficient fk (28u) to its initial value of 1.0. In the above equation (90) for calculating the flow correction coefficient fk (28u), the flow correction coefficient Ckx (28v) is fixed because it depends on the characteristics of the detection unit (10). Therefore, the rate of change must be initialized at the start or when calibrating the mass flow rate.

[0342] The rate of change is calculated by the thickness diagnosis unit (70) and the density error diagnosis simple correction unit (80). An initial value is stored in the flow rate error diagnosis simple correction unit (90), and the rate of change from the initial value is used. Note that it is also possible to configure the initialization by an initialization command. The following formula (91) using the rate of change from the initial value is shown.

[0343]

number

[0344] At this time, as initial values, an initial stiffness change rate aKc0 (522e), an initial thickness change rate rtc0 (522d), an initial coefficient change rate aCdc0 (522a), and an initial coefficient change rate afac0 (522b) are used.

[0345] When calibrating mass flow rate, the flow rate correction coefficient fk (28u) is set to an initial value of 1.0. Mass flow rate calibration and density calibration are not necessarily synchronized. In particular, if the stiffness has changed since the previous density calibration, a flow rate error will occur. Therefore, to minimize errors in the simple correction of the flow rate measurement coefficient, density calibration must be performed at the same time as mass flow rate calibration.

[0346] Changing the flow rate measurement coefficient creates discontinuities in the flow rate measurement results. If the flow rate fluctuations are within the allowable range, there is also the option of prioritizing the continuity of the measurement values. If the flow rate correction coefficient before simple correction is fk and the flow rate correction coefficient after correction is fkq, the flow rate fluctuation rate rqd (521c) is defined as equation (92) below. The mass flow rate before simple correction is mass flow rate Qmc, and the mass flow rate after simple correction is mass flow rate Qmcq.

[0347]

number

[0348] The flow rate fluctuation tolerance is set to rqdlim and is compared with the flow rate change rate rqd. By determining whether or not the flow rate correction coefficient fk can be replaced, small fluctuations can be suppressed. The flow rate fluctuation tolerance rqdlim indicates the flow rate fluctuation tolerance (522h). In this case, the conditional formula is the following formula (93).

[0349]

number

[0350] It is always replaced when the flow rate fluctuation tolerance ratio value rqdlim is set to 0. When the flow rate correction coefficient fk is not updated, the flow rate correction coefficient fk maintains the value at the time of the previous update.

[0351] Using the flow rate correction coefficient fkq after simple correction, the flow rate error rate rqe (521b) of the mass flow measurement from the time of flow rate calibration is calculated as the following equation (94). The flow rate error rate rqe (521b) is used as a basis for diagnosing the flow rate error. The mass flow rate at the time of flow rate calibration is defined as the mass flow rate Qm.

[0352]

number

[0353] The flow rate error rate rqe (521b) is compared with the flow rate error alarm value rqelim, and if the fluctuation becomes large, a flow rate diagnosis abnormality (521r) is set. The flow rate error alarm value rqelim indicates the flow rate error alarm value (522r). At this time, the condition formula is the following formula (95).

[0354]

number

[0355] By setting the flow rate diagnosis abnormality (521r), it is possible to inform the user of an abnormality in the device. In addition, a method can be considered in which the flow rate error rate rqe is displayed on the display operation unit (30) of the Coriolis mass flowmeter (1) or on an external device (31) and whether or not the coefficient should be updated is input.

[0356] The flow rate error diagnosis and simple correction process described above includes a diagnosis process that monitors the flow rate error and issues an alarm, and a simple correction process that updates the flow rate correction coefficient fkq to reduce the density error, and it is possible to use only one of them.

[0357] (3-4-2. Flow error diagnosis and simple correction process) The overall flow rate error diagnosis and simple correction process will be described with reference to Fig. 23. Fig. 23 is a diagram showing an example of the overall flow rate error diagnosis and simple correction process according to the embodiment. The configuration of the flow rate error diagnosis simple correction unit (90) of the diagnosis device (2) will be described below.

[0358] As shown in Fig. 23, the flow rate error diagnosis simple correction unit (90) is a part of the diagnosis control unit (60). The flow rate error diagnosis simple correction unit (90) has an initialization determination unit (91), a flow rate initialization unit (92), a rigidity thickness initialization unit (93), and a flow rate correction coefficient update unit (94), which respectively execute an initialization determination process, a flow rate initialization process, a rigidity thickness initialization process, and a flow rate correction coefficient update process. The flow rate error diagnosis simple correction unit (90) updates the flow rate correction coefficient fk (28u) based on the thickness diagnosis result (321) and the density diagnosis result (421). Here, the flow rate correction coefficient fk (28u) is included in the parameters (28) of the conversion unit (20).

[0359] The initialization determination unit (91) sets an initialization execution signal 1 (507), an initialization execution signal 2 (508), or an update execution signal (509). The flow rate initialization unit (92) executes initialization processing when the mass flow rate calibration unit (41) is executed, and executes processing when the initialization execution signal 1 (507) is set. The rigidity thickness initialization unit (93) executes initialization processing when the thickness diagnosis unit (70) or the density error diagnosis simple correction unit (80) is executed, and executes processing when the initialization execution signal 2 (508) is set. The flow rate correction coefficient update unit (94) updates the flow rate measurement coefficient, and executes processing when the update execution signal (509) is set.

[0360] (3-4-3. Initialization Judgment Process) The initialization determination process will be described with reference to FIG. 24. The initialization determination process by the initialization determination unit (91) of the flow error diagnosis simple correction unit (90) will be described. FIG. 24 is a diagram showing an example of the flow error diagnosis simple correction process 1 according to the embodiment. As shown in FIG. 24, the initialization determination unit (91) executes the process when the flow calibration completion signal (121) or the density diagnosis completion signal (431) is set. The initialization determination unit (91) also outputs an initialization execution signal 1 (507), an initialization execution signal 2 (508), and an update execution signal (509) based on the initialization flag (321t) as the thickness diagnosis result (321), the initialization flag (421t) as the density diagnosis result (421), and the initial date and time (522x) and the initialization execution command (522u) as the flow diagnosis set value (522). The flow of the initialization determination process will be described later in [5. Flow of each process of the diagnosis device (2)].

[0361] (3-4-4. Flow rate initialization process) The density flow rate initialization process by the flow rate initialization unit (92) of the flow rate error diagnosis simple correction unit (90) will be described with reference to Fig. 25. Fig. 25 is a diagram showing an example of the flow rate error diagnosis and simple correction process 3 according to the embodiment. As shown in Fig. 25, the flow rate initialization unit (92) has a rigidity thickness selection unit (95).

[0362] The flow rate initialization unit (92) initializes the flow rate diagnosis set value (522) by the rigidity / thickness selection unit (95) as described below. That is, the flow rate initialization unit (92) selects the initial value of the change rate. At this time, if the diagnosis date and time (321x) has not been set, the flow rate initialization unit (92) sets the initial coefficient change rate aCdc0 (522a), the initial coefficient change rate afac0 (522b), the initial thickness change rate rtc0 (522d), and the initial rigidity change rate aKc0 (522e) to a value of 1.0. On the other hand, when the diagnosis date and time (321x) is set, the flow rate initialization unit (92) assigns the value of the coefficient change rate aCdc (421c) to the initial coefficient change rate aCdc0 (522a), assigns the value of the coefficient change rate afac (421d) to the initial coefficient change rate afac0 (522b), assigns the value of the thickness change rate rtc (321d) to the initial thickness change rate rtc0 (522d), assigns the value of the stiffness change rate aKc (321e) to the initial stiffness change rate aKc0 (522e), assigns the value of the flow calibration date and time (28h) to the initial date and time (522x), assigns the value of the flow calibration drive time (28i) to the initial drive time (522y), and assigns the value of the flow calibration integrated flow rate (28j) to the initial integrated flow rate (522z). The flow rate initialization unit 92 also sets an initialization execution command 522u to perform initialization at the next density calibration, and sets the flow rate correction coefficient fk 28u to an initial value of 1.0.

[0363] The flow rate initialization unit (92) initializes the flow rate diagnosis result (521) as follows. That is, the flow rate initialization unit (92) assigns a value of 1.0 to the flow rate correction coefficient fkq (521a), assigns a value of 0.0 to the flow rate error rate rqe (521b), assigns a value of 0.0 to the flow rate fluctuation rate rqd (521c), assigns the value of the flow rate calibration date and time (28h) to the correction date and time (521x), assigns the value of the flow rate calibration drive time (28i) to the drive time (521y), and assigns the value of the flow rate calibration integrated flow rate (28j) to the integrated flow rate (521z). The flow rate initialization unit (92) also resets the flow rate diagnosis abnormality (521r). The flow rate initialization unit (92) also sets an initialization flag (521t) to indicate that the flow rate diagnosis result (521) has been initialized. The flow rate initialization unit 92 also sets the update flag 521s to indicate that the flow rate diagnosis result 521 has been updated, and resets the flow rate calibration completion signal 121 to wait for the next flow rate calibration to be performed.

[0364] (3-4-5. Initialization of rigidity and thickness) The rigidity thickness initialization process by the rigidity thickness initialization unit (93) of the flow rate error diagnosis simple correction unit (90) will be described with reference to Fig. 26. Fig. 26 is a diagram showing an example of flow rate error diagnosis and simple correction process 3 according to the embodiment.

[0365] The rigidity thickness initialization unit (93) initializes the flow diagnostic setpoint (522) as follows. That is, the rigidity thickness initialization unit (93) assigns the value of the coefficient change rate aCdc (421c) to the initial coefficient change rate aCdc0 (522a), assigns the value of the coefficient change rate afac (421d) to the initial coefficient change rate afac0 (522b), assigns the value of the thickness change rate rtc (321d) to the initial thickness change rate rtc0 (522d), assigns the value of the rigidity change rate aKc (321e) to the initial rigidity change rate aKc0 (522e), assigns the value of the diagnosis date and time (321x) to the initial date and time (522x), assigns the value of the drive time (321y) to the initial drive time (522y), and assigns the value of the integrated flow rate (321z) to the initial integrated flow rate (522z). The rigidity / thickness initialization unit 93 also resets the initialization execution command 522u and waits for an external initialization command, and sets the flow rate correction coefficient fk 28u to an initial value of 1.0.

[0366] The rigid thickness initialization unit (93) initializes the flow rate diagnosis result (521) as follows. That is, the rigid thickness initialization unit (93) assigns a value of 1.0 to the flow rate correction coefficient fkq (521a), a value of 0.0 to the flow rate error rate rqe (521b), a value of 0.0 to the flow rate fluctuation rate rqd (521c), the value of the diagnosis date and time (321x) to the correction date and time (521x), the value of the drive time (321y) to the drive time (521y), and the value of the integrated flow rate (321z) to the integrated flow rate (521z). The rigid thickness initialization unit (93) also resets the flow rate diagnosis abnormality (521r). The rigidity thickness initialization unit 93 also sets an initialization flag 521t to indicate that the flow rate diagnosis result 521 has been initialized, and an update flag 521s to indicate that the flow rate diagnosis result 521 has been updated. The rigidity thickness initialization unit 93 also resets the density diagnosis completion signal 431, and waits for the next density error diagnosis to be performed.

[0367] (3-4-6. Flow rate correction coefficient update process) The flow rate correction coefficient updating process by the flow rate correction coefficient updating unit (94) of the flow rate error diagnosis simple correction unit (90) will be described with reference to Fig. 27. Fig. 27 is a diagram showing an example of flow rate error diagnosis and simple correction process 4 according to the embodiment. As shown in Fig. 27, it has a flow rate correction coefficient calculation unit (96), a flow rate fluctuation comparator 1 (97), a flow rate correction coefficient setter (98), and a flow rate fluctuation comparator 2 (99).

[0368] The flow rate correction coefficient updating unit (94) calculates the flow rate correction coefficient, the flow rate error rate, and the flow rate fluctuation rate using the flow rate correction coefficient calculation unit (96). That is, the flow rate correction coefficient updating unit (94) calculates the flow rate correction coefficient fkq using the above equation (91) and substitutes it for the flow rate correction coefficient fkq (521a). The flow rate correction coefficient updating unit (94) also calculates the flow rate fluctuation rate rqd using the above equation (92) and substitutes it for the flow rate fluctuation rate rqd (521c). The flow rate correction coefficient updating unit (94) also calculates the flow rate error rate rqe using the above equation (94) and substitutes it for the flow rate error rate rqe (521b).

[0369] The flow rate correction coefficient update unit (94) sets the flow rate diagnosis result (521) as follows: That is, the flow rate correction coefficient update unit (94) assigns the value of the diagnosis date and time (321x) to the correction date and time (521x), assigns the value of the drive time (321y) to the drive time (521y), and assigns the value of the integrated flow rate (321z) to the integrated flow rate (521z).

[0370] The flow rate correction coefficient updating unit (94) uses the flow rate fluctuation comparator 1 (97) to compare the absolute value of the flow rate fluctuation rate rqd (521c) with the flow rate fluctuation allowable value (522h). At this time, the flow rate correction coefficient updating unit (94) makes a determination using the above formula (93). If the absolute value of the flow rate fluctuation rate rqd (521c) is greater than the flow rate fluctuation allowable value (522h), the flow rate correction coefficient updating unit (94) sets the flow rate coefficient selection signal (504) and sets the flow rate correction coefficient fkq (521a) to the flow rate correction coefficient fk (28u) using the flow rate correction coefficient setter (98).

[0371] The flow rate correction coefficient updating unit (94) executes the following process using the flow rate fluctuation comparator 2 (99). That is, the flow rate correction coefficient updating unit (94) compares the absolute value of the flow rate error rate rqe (521b) with the flow rate error warning value (522r) using the above formula (95). If the absolute value of the flow rate error rate rqe (521b) is greater than the flow rate error warning value (522r), the flow rate correction coefficient updating unit (94) sets a flow rate diagnosis abnormality (521r). On the other hand, if the absolute value of the flow rate error rate rqe (521b) is equal to or less than the flow rate error warning value (522r), the flow rate correction coefficient updating unit (94) resets the flow rate diagnosis abnormality (521r). The flow rate correction coefficient updating unit (94) also resets the initialization flag (521t) to indicate that the flow rate diagnosis result (521) has not been initialized. The flow rate correction coefficient update unit 94 also sets the update flag 521s to indicate that the flow rate diagnosis result 521 has been updated, and resets the density diagnosis completion signal 431 to wait for the next density error diagnosis to be performed.

[0372] (3-5. Timing prediction diagnostic processing) 28 to 32 and equations, a timing prediction diagnostic process executed by the timing prediction diagnostic unit (100) of the diagnostic device (2) according to the embodiment will be described. Below, a theoretical formula for the timing prediction diagnostic process will be explained, followed by an explanation of the entire timing prediction diagnostic process, timing prediction diagnostic process using the stiffness damping diagnostic result, timing prediction diagnostic process using the wall thickness diagnostic result, timing prediction diagnostic process using the density diagnostic result, and timing prediction diagnostic process using the flow rate diagnostic result, in that order.

[0373] (3-5-1. Theoretical formula for timing prediction diagnostic processing) The theoretical formula for timing prediction diagnosis processing will be explained below. Here, an example of thickness change dtc (321c) is shown as an example of a formula used in timing prediction diagnosis. Similar formulas can also be created for other diagnostic values. The following diagnostic values ​​are important for timing prediction. Here, they are defined as inner diameter dcc (321a), thickness tcc (321b), thickness change rate rtc (321d), stiffness change rate aKc (321e), damping change rate aDc (321f), Q value change rate aQc (321g), coefficient change rate aCdc (421c), coefficient change rate afac (421d), density error Δρ0 (421f), flow correction coefficient fkq (521a), and flow error rate rqe (521b).

[0374] Here, the changes are approximated using an approximate straight line or curve from multiple data points, and timing prediction diagnosis is performed. The parameters and correction coefficients used are determined using multiple regression analysis, AI inference, etc. Using the maximum rate of change from multiple data, predictions can be made under the conditions where the change is greatest.

[0375] Here, an example is shown in which an approximation line is created from the diagnosis results of two points and timing prediction diagnosis is performed. If the coefficient x is the history information number, x=1 is the start, x=2 is the present, the date and time is Tmx, the driving time is Tdx, the integrated flow rate is Qmx, and the change in thickness is dtx, the approximation line is created as shown in the following equations (96) to (98).

[0376]

number

[0377]

number

[0378]

number

[0379] In the above equation (96), the coefficient am indicates the change in thickness per date and time. The coefficient bm indicates the change in thickness at x=0. Moreover, in the above equation (97), the coefficient ad indicates the change in thickness per drive hour. The coefficient bd indicates the change in thickness at x=0. Moreover, in the above equation (96), the coefficient aq indicates the change in thickness per integrated flow rate. The coefficient bq indicates the change in thickness at x=0. Here, from the above equations (96) to (98), the following equations (99) to (104) are obtained.

[0380]

number

[0381]

number

[0382]

number

[0383]

number

[0384]

number

[0385]

number

[0386] Here, a diagnosis target value dts of the wall thickness change is set. A predicted value for reaching the diagnosis target value dts is obtained. If the predicted value is expressed by the date and time Tme, the drive time Tde, and the mass flow rate Qme, the following formulas (105) to (107) are obtained.

[0387]

number

[0388]

number

[0389]

number

[0390] The flow rate correction coefficient fk (28u) indicates the flow rate error that has occurred. By inputting the flow rate correction coefficient fk (28u) into the flow rate measurement formula, the flow rate error can be corrected, but since the flow rate correction coefficient fk (28u) is an estimate, it contains a certain amount of error. By using the flow rate correction coefficient fk (28u) to perform timing prediction diagnosis, it is possible to predict the date and time, operating time, and mass flow rate when the error limit value will be reached.

[0391] (3-5-2. Overall processing of timing prediction diagnosis) The entire timing prediction diagnosis process will be described with reference to Fig. 28. Fig. 28 is a diagram showing an example of the entire timing prediction diagnosis process according to the embodiment. The configuration of the timing prediction diagnosis unit (100) of the diagnosis device (2) will be described below.

[0392] The timing prediction diagnosis unit (100) has a history unit (101), a change trend calculation unit (102), and a prediction unit (103), and predicts timing from any of the results of the stiffness damping diagnosis unit (61), the wall thickness diagnosis unit (70), the density error diagnosis simple correction unit (80), and the flow rate error diagnosis simple correction unit (90).

[0393] First, the timing prediction diagnosis unit (100) determines whether an update flag is set. Here, the timing prediction diagnosis unit (100) checks the update flag of the diagnosis data included in the result of each diagnosis. That is, the timing prediction diagnosis unit (100) checks the update flag (221s) included in the stiffness damping diagnosis result (221) which is the diagnosis result of the stiffness damping diagnosis unit (61), checks the update flag (321s) included in the thickness diagnosis result (321) which is the diagnosis result of the thickness diagnosis unit (70), checks the update flag (421s) included in the density diagnosis result (421) which is the diagnosis result of the density error diagnosis simple correction unit (80), and checks the update flag (521s) included in the flow rate diagnosis result (521) which is the correction result of the flow rate error diagnosis simple correction unit (90). If none of the above update flags is set, the timing prediction diagnosis unit (100) ends the process.

[0394] Next, the timing prediction diagnosis unit (100) stores the above diagnosis result by the history unit (101). Then, the timing prediction diagnosis unit (100) calculates a change trend value (601) from the updated data in the history unit (101) by the change trend calculation unit (102). At this time, the timing prediction diagnosis unit (100) approximates the change by the approximation line or approximation curve shown in the above-mentioned equations (99) to (104). The timing prediction diagnosis unit (100) determines the parameters and correction coefficients to be used by using multiple regression analysis, AI inference, etc.

[0395] Then, the timing prediction diagnosis unit (100) outputs a timing prediction diagnosis result (603) from the change trend value (601) and the diagnosis target value (602) by the prediction unit (103). At this time, the timing prediction diagnosis unit (100) performs the calculations shown in the above equations (105) to (107). The timing prediction diagnosis unit (100) transmits the calculated timing prediction diagnosis result (603) to the display operation unit (30) of the Coriolis mass flowmeter (1) or the external device (31). Finally, the timing prediction diagnosis unit (100) resets the update flag.

[0396] (3-5-3. Timing prediction diagnosis process using stiffness damping diagnosis results) A timing prediction diagnostic process using a stiffness damping diagnosis result will be described with reference to Fig. 29. Fig. 29 is a diagram showing an example of timing prediction diagnostic process 1 according to the embodiment.

[0397] The timing prediction diagnosis unit (100) performs timing prediction diagnosis from the stiffness decay diagnosis result (221) of the stiffness decay diagnosis unit (61) as described below. That is, the timing prediction diagnosis unit (100) executes timing prediction diagnosis processing when the update flag (221s) included in the stiffness decay diagnosis result (221) is set. At this time, the history unit (101) of the timing prediction diagnosis unit (100) imports data in response to the setting of the update flag (221s). The history unit (101) is also capable of selecting necessary data from the input data. When the importing is completed, the history unit (101) resets the update flag (221s).

[0398] (3-5-4. Timing prediction diagnosis process using thickness diagnosis results) The timing prediction diagnostic process using the wall thickness diagnosis result will be described with reference to Fig. 30. Fig. 30 is a diagram showing an example of timing prediction diagnostic process 2 according to the embodiment.

[0399] The timing prediction diagnosis unit (100) performs timing prediction diagnosis from the wall thickness diagnosis result (321) of the wall thickness diagnosis unit (70) as described below. That is, the timing prediction diagnosis unit (100) executes timing prediction diagnosis processing when an update flag (321s) included in the wall thickness diagnosis result (321) is set. The history unit (101) of the timing prediction diagnosis unit (100) imports data when the update flag (321s) is set. The history unit (101) is also capable of selecting necessary data from the input data. When the import is completed, the history unit (101) resets the update flag (321s).

[0400] (3-5-5. Timing prediction diagnosis processing using density diagnosis results) A timing prediction diagnostic process using a density diagnosis result will be described with reference to Fig. 31. Fig. 31 is a diagram showing an example of a timing prediction diagnostic process 3 according to the embodiment.

[0401] The timing prediction diagnosis unit (100) performs timing prediction diagnosis from the density diagnosis result (421) of the density error diagnosis simple correction unit (80) as described below. That is, the timing prediction diagnosis unit (100) executes timing prediction diagnosis processing when the update flag (421s) included in the density diagnosis result (421) is set. The history unit (101) of the timing prediction diagnosis unit (100) imports data when the update flag (421s) is set. The history unit (101) is also capable of selecting necessary data from the input data. When the import is completed, the history unit (101) resets the update flag (421s).

[0402] (3-5-6. Timing prediction diagnostic process using flow rate diagnostic results) A timing prediction diagnostic process using a flow rate diagnosis result will be described with reference to Fig. 32. Fig. 32 is a diagram showing an example of timing prediction diagnostic process 4 according to the embodiment.

[0403] The timing prediction diagnosis unit (100) performs timing prediction diagnosis from the flow rate diagnosis result (521) of the flow rate error diagnosis simple correction unit (90) as described below. That is, the timing prediction diagnosis unit (100) executes timing prediction diagnosis processing when the update flag (521s) included in the flow rate diagnosis result (521) is set. The history unit (101) of the timing prediction diagnosis unit (100) imports data when the update flag (521s) is set. The history unit (101) is also capable of selecting necessary data from the input data. When the import is completed, the history unit (101) resets the update flag (521s).

[0404] [4. Processing results of each process of the diagnostic device (2)] 33 to 40, the results of each process of the diagnostic device (2) according to the embodiment and their effects will be described. The results of the thickness diagnostic, density diagnostic, flow rate diagnostic, and timing prediction diagnostic will be described in this order.

[0405] (4-1. Thickness diagnosis results and effects) The wall thickness diagnosis results and effects will be described with reference to Figures 33 to 34. In the following, wall thickness diagnosis result 1 and wall thickness diagnosis result 2 will be described, and then the effects of the wall thickness diagnosis process will be described.

[0406] (4-1-1. Thickness diagnosis result 1) The wall thickness diagnosis result 1 will be explained using Figure 33. The wall thickness diagnosis result 1 shows the results of flowing a corrosive fluid into a Coriolis mass flowmeter (1), performing density calibration before and after corrosion, and measuring the stiffness change rate and damping change rate together with the density calibration.

[0407] The measurement results are shown in Figure 33 (1). With the drive gain fixed, the stiffness change rate aKc (221a) was calculated using the above formula (43), and the result is shown in "aKc". The inner diameter dc2 was calculated from the stiffness change rate aKc (221a) using the above formula (54), and the result is shown in "dc2". Also, the value without correction using the above formula (55) is shown. The vibration tube inner diameter dc calculated using the above formula (70) from the density calibration result is shown in "dc". The stiffness change rate aK calculated using the above formula (74) from the density calibration result is shown in "aK". The stiffness change rate aK was inserted into the above formula (54), and the inner diameter of the vibration tube calculated using the formula for the second moment of area is shown in "dc2d". Also, the value without correction using the above formula (55) is shown.

[0408] Figure 33 (3) shows the change in the inner diameter. The inner diameter dc calculated from the density measurement coefficient and the inner diameter dc2d calculated from the equation for the second moment of area have the same tendency, but there is a difference. This is thought to be because the second moment of area is expressed in the simple form of equation (51).

[0409] Figure 33(4) shows the relationship between the inner diameter "dc", the inner diameter "dc2", and the inner diameter "dc2d". As Figure 33(4) shows, there is a high correlation. The correction coefficient Cdc1 (322f) of the linear expression in equation (55) is found from the inner diameter "dc" and the inner diameter "dc2d". The correction coefficient Cdc1 (322f) corrects the error caused by using the equation for the second moment of area.

[0410] Figure 33(2) shows the inner diameter after linear correction. The inner diameter dccd is the corrected value of the inner diameter "dc2d" and is equal to the inner diameter dc in Figure 33(1). By using the linear form of the above equation (55), the inner diameter calculated by the simplified equation (52) for the second moment of area can be corrected to a value closer to reality.

[0411] (4-1-2. Thickness diagnosis result 2) The wall thickness diagnosis result 2 will be explained with reference to Fig. 34. The wall thickness diagnosis result 2 shows the result of diagnosis performed by attaching a total of 0.978g of vinyl tape to the outside of the vibration tube.

[0412] The measurement results are shown in Figure 34. Here, "Normal" indicates the case where vinyl tape was not attached, and "Tape" indicates the case where vinyl tape was attached, and each was diagnosed five times with air and water. The stiffness change rate aKc (221a), Q value change rate aQc (221c), and thickness change dtc (321c) are shown. The thickness change rate rtc (321d) was calculated from the stiffness change rate aKc (221a). The stiffness change rate aKc (221a) and Q value change rate aQc (221c) indicate the change rates based on "Normal", air, and the first test.

[0413] The wall thickness change rate rtc (321d) calculated from the stiffness change rate aKc (221a) hardly changes. This shows that adhesion does not affect stiffness. The amount of change in the Q value is large, so adhesion should be judged from the change in the Q value. Since the Q value changes depending on the fluid, it is necessary to compare under the same conditions.

[0414] (4-1-3. Effects) As described above, the change in thickness can be estimated from the change in rigidity and the design information of the vibration tube. In this case, the formula for the moment of inertia of a cantilever beam with a circular cross section does not take into account the shape of the vibration tube, resulting in a discrepancy with the actual value. By correcting with an approximate straight line or curve, it is possible to estimate an inner diameter that is closer to the actual value. Furthermore, the thickness is a value that is directly related to corrosion and adhesion, and it is easier to set a tolerance for it than the rate of change in rigidity. Furthermore, it is possible to set a tolerance for the change in thickness and notify of abnormalities by issuing an alarm.

[0415] (4-2. Density diagnosis results and effects) The density diagnosis result and effect will be described with reference to Fig. 35. In the following, the density diagnosis result will be described, and then the effect of the density diagnosis process will be described.

[0416] (4-2-1. Density diagnosis results) The density diagnosis results are explained using Figure 35. The density diagnosis results are shown by flowing a corrosive fluid through a Coriolis mass flowmeter (1), calibrating the density before and after corrosion, and measuring the stiffness change rate and damping change rate along with the calibration. In addition, the density error is estimated from the results, and the density measurement coefficient is simply corrected.

[0417] The measurement results are shown in Figure 35 (1). The density measurement coefficient Cdc and the density measurement coefficient fac were measured by density calibration. The frequency fd was calculated from the above formula (81). The frequencies of air and water are shown. The density error Δρd was calculated from the above formula (82) when the density measurement coefficient #0 was used. Using the stiffness change rate aKc (221a) and the inner diameter dcc (321a), the density measurement coefficient Cdcc (421a) was calculated from the above formula (76), and the density measurement coefficient facc (421b) was calculated from the above formula (78). In addition, the density error Δρe was calculated from the above formula (83). The density error Δρe was calculated before and after updating the density measurement coefficient Cdcc (421a) and the density measurement coefficient facc (421b).

[0418] Figure 35 (3) shows the density error Δρd and the density error Δρe. The density error Δρd shows the error when the density measurement coefficient is not changed from the initial value. As corrosion progresses, the error increases. The density error Δρe shows the density error when the density measurement coefficient is updated. It also shows the error just before the update and the error after the update. The density error can be reduced by updating the density measurement coefficient using the stiffness change rate aKc (221a) and the inner diameter dcc (321a).

[0419] Figure 35 (4) shows the density measurement coefficient. The density measurement coefficient Cdcc (421a) and the density measurement coefficient facc (421b) obtained from Cdc and fac obtained by density calibration, the stiffness change rate aKc (221a) and the inner diameter dcc (321a) are shown. Although there are some differences, they show the same trend of change.

[0420] The density diagnosis result is shown in Figure 35 (2). The density variation Δρ (421e) and density error Δρ0 (421f) were calculated from the density measurement coefficient Cdcc (421a) and density measurement coefficient facc (421b) calculated from the stiffness change rate aKc (221a) and the inside diameter dcc (321a). By setting a density error alarm value (422r) for the density error Δρ0 (421f), it is possible to determine whether the density diagnosis is abnormal (421r).

[0421] 35(5) shows the density error Δρd calculated from the density calibration result and the density error Δρ0 (421f) obtained by the estimation process according to the embodiment described above. The density errors have the same tendency.

[0422] (4-2-2. Effects) As described above, the density measurement coefficient can be estimated from the stiffness change and wall thickness change. By replacing the density measurement coefficient, a simple correction of the density measurement is performed, and the density error is reduced. By updating the density measurement coefficient, the density calibration cycle is lengthened. Changing the density measurement coefficient through density calibration creates discontinuities in the density measurement results. If the density fluctuation is within the tolerance, there is also the option of prioritizing the continuity of the measurement values. By setting the density fluctuation tolerance, it is possible to determine whether or not to replace the density measurement coefficient, and to suppress fluctuations in the density measurement results.

[0423] In addition, density error can be estimated from changes in the density measurement coefficient. Since density error depends on the density of the object being measured, the density error is calculated taking into account the density of the object being measured. It is also possible to set a density error tolerance from the time of density calibration and notify of abnormalities by issuing an alarm. The occurrence of a density error indicates that an error has also occurred in the mass flow measurement results. In addition, it is also possible to notify that readjustment of the measuring instrument is necessary.

[0424] (4-3. Flow rate diagnosis results and effects) The flow rate diagnosis results and effects will be described with reference to Figures 36 to 39. Below, flow rate diagnosis result 1 and flow rate diagnosis result 2 will be described, and then the effects of the flow rate error diagnosis and simple correction process will be described.

[0425] (4-3-1. Flow rate diagnosis result 1) Flow rate diagnosis result 1 will be explained using Figure 36. Here, consider a situation in which the flow rate error increases due to corrosion. Due to corrosion, the flow rate measurement coefficient Cq decreases and the ratio θ0 / f of the phase difference θ0 and the frequency f increases. An error occurs because the flow rate measurement coefficient Cq (28f) is the value before corrosion.

[0426] Figure 36 shows the relationship between error and simple correction. If the error variation per measurement is -0.1%, then 10 measurements will result in an error of -1%. If the initial value of the flow measurement coefficient Cq (28f) continues to be used, an error of +1.0% will be produced in the 10th flow measurement. "Qe=-0.1%" shows the flow error when flow calibration is not performed.

[0427] The flow rate error was calculated when the flow rate correction coefficient fk (28u) was updated. The flow rate error when the rate of change of the flow rate correction coefficient fk (28u) is equal to the flow rate error is shown as "fk = -0.1%". In this case, the flow rate measurement coefficient Cq (28f) can be corrected by using the flow rate correction coefficient fk (28u). The flow rate error returns to zero by performing density calibration.

[0428] The error when the rate of change of the flow correction coefficient fk (28u) is -0.05% / calibration is shown as "fk=-0.05%". When it is -0.15% / calibration, it is shown as "fk=-0.15%". Error can be suppressed by correction. If the allowable error is ±0.5%, without correction with coefficient 1, it will take 5 times to reach the allowable error, but with correction it will take 10 times. This shows that the interval between flow calibrations can be extended by using the flow correction coefficient fk (28u) to perform simple correction of the flow measurement coefficient.

[0429] (4-3-2. Flow rate diagnosis result 2) The flow rate diagnosis result 2 will be explained using Figures 37 to 39. Figure 37 (1) shows the stiffness change rate, wall thickness change rate, density measurement coefficient change rate, and flow rate error rate when corrosion was repeated multiple times. The drive gain in Figure 37 (1) was fixed, and water was allowed to flow and the flow rate error rate Qe was measured at the same time as the experiment to determine the stiffness change rate aK. The wall thickness change rate rtc (321d), coefficient change rate aCdc (421c), and coefficient change rate afac (421d) were obtained from the stiffness change rate aKc (321e). The change in the flow rate measurement coefficient Cq (28f) was calculated from the flow rate error rate Qe, and the change rate aCq was obtained.

[0430] FIG. 37(2) shows the relationship between the stiffness change rate aKc (321e), the wall thickness change rate rtc (321d), the coefficient change rate aCdc (421c), the coefficient change rate afac (421d), and the change rate aCq of the flow measurement coefficient Cq (28f). The flow measurement coefficient Cq (28f) is updated during flow calibration, and a flow error occurs until it is updated. The flow error can be easily corrected by making the flow correction coefficient fk (28u) change in the same way as the change rate aCq. The trends of the change rate aCq and each change rate match, but there are some differences as the corrosion becomes larger. The change in the coefficient change rate afac (421d) is small. The change in the flow measurement coefficient Cq (28f) can be easily corrected by at least one of the coefficient change rate aCdc (421c), the wall thickness change rate rtc (321d), and the stiffness change rate aKc (321e).

[0431] Figure 37 (3) shows the flow rate error when flow rate error diagnosis and simple correction processing are performed using the results of Figure 37 (1). The flow rate error when simple correction is not performed is Qe. When simple correction is performed, the coefficient name used to calculate the flow rate correction coefficient fk (28u) is shown. In the above formula (91), one of Ckx (x = 1, 2, 3, 4) is set to the value 1, and the others are set to the value 0. From the first time onwards, there are two simple correction results, showing before and after updating the flow rate correction coefficient fk (28u). When the coefficient change rate afac (421d) is used, the error is only slightly reduced, and the effect of correction is small. This is because the change in the coefficient change rate afac (421d) is smaller than the change rate aCq. The results when the other three parameters are used are equivalent. Since the change rate is larger than aCq, the flow rate error after simple correction becomes negative with each iteration.

[0432] Figure 37 (4) shows the relationship between the change in the flow coefficient Cq and the wall thickness change rate rtc (321d), the stiffness change rate aKc (321e), the coefficient change rate aCdc (421c), and the coefficient change rate afac (421d). There is a high correlation between all variables. The slope of the coefficient change rate afac (421d) is small.

[0433] Figure 38 (1) shows the results of determining the flow correction coefficient Ckx (28v) using multiple regression analysis. A blank indicates that the value is 0. The results show the case where the four parameters are used independently and the case where the correction coefficient is determined by combining the stiffness change rate aKc (321e) and the wall thickness change rate rtc (321d), the coefficient change rate aCdc (421c) and the coefficient change rate afac (421d). The correlation is high in all cases. Although the combination and F value become small, the combination is also effective. By calculating the flow correction coefficient fk (28u) using the coefficient change rate aCdc (421c), the wall thickness change rate rtc (321d) or the stiffness change rate aKc (321e), the wall thickness change rate rtc (321d) or the coefficient change rate aCdc (421c), and the coefficient change rate afac (421d), simple correction of the mass flow rate is possible.

[0434] Figure 38(2) shows the flow rate correction result when the flow rate correction coefficient Ckx(28v) in Figure 38(1) is used. The error returns to zero by performing density calibration.

[0435] Figure 39 (1) shows the results of estimating the flow rate error. The flow rate correction coefficient fk (28u) was found from equation (91) above, and the flow rate error rate rqe (521b) was calculated from equation (94) above. One of the four variables was used for the flow rate correction coefficient fk (28u). Shown here is the result rqex1 when the flow rate correction coefficient Ckx (28v) corresponding to the variable used in equation (91) above is set to the value 1.0, and shown here is the result rqex2 when the value found by correlation between the flow rate correction coefficient Ckx (28v) is used.

[0436] Figure 39 (2) shows the change in the flow rate error Qe and the flow rate error rate rqex1. The change in the coefficient change rate afac (421d) is small. The flow rate error rate rqe (521b) calculated using the stiffness change rate aKc (321e), the wall thickness change rate rtc (321d) and the coefficient change rate aCdc (421c) shows the same change trend as the flow rate error Qe.

[0437] Figure 39 (3) shows the change in the flow rate error Qe and the flow rate error rate rqex2. The change trend of each result coincided with that of the flow rate error Qe. From the above, by setting the flow rate error alarm value (522r) for the calculated flow rate error rate rqe (521b), it is possible to determine whether the flow rate diagnosis is abnormal (521r).

[0438] (4-3-3. Effects) As described above, the rate of change in wall thickness and the rate of change in density measurement coefficient can be calculated from the rate of change in rigidity and the design information of the vibrating tube. Using these to perform simple correction of the flow measurement coefficient, the flow rate error can be reduced without flow rate calibration. There is a high correlation between the error in mass flow rate and the rate of change in rigidity, wall thickness, and density measurement coefficient, but there is a difference in the slope. By correcting with an approximate straight line or approximate curve, the error of the simple correction can be reduced. The parameters and correction coefficients to be used can be determined using multiple regression analysis, AI inference, etc.

[0439] Furthermore, the flow rate error can be estimated from the change in the flow rate correction coefficient. An error can be notified by setting a tolerance for the flow rate error and issuing an alarm. Changing the flow rate correction coefficient creates a discontinuity in the mass flow measurement results. If the flow rate fluctuation caused by changing the flow rate correction coefficient is within the tolerance range, there is also the option of prioritizing the continuity of the measurement value. Setting a flow rate fluctuation tolerance determines whether or not the flow rate correction coefficient can be replaced, and suppresses fluctuations in the mass flow measurement results. Coriolis mass flowmeters (1) are characterized by their ability to perform accurate measurements. Mass flow measurement is one of the basic processes of a Coriolis mass flowmeter (1), and by monitoring the flow rate error, it is possible to maintain the target accuracy.

[0440] (4-4. Timing prediction diagnosis results) The timing prediction diagnostic result and the effect will be described with reference to Fig. 40. In the following, the timing prediction diagnostic result will be described, and then the effect of the timing prediction diagnostic process will be described.

[0441] (4-4-1. Timing prediction diagnosis results) FIG. 40 shows an example of calculation of timing prediction diagnosis. Two points each of date and time, operating time, accumulated flow rate, and density error are assumed. These are shown in "Data 1" and "Data 2". The coefficients of the approximate line obtained from the above-mentioned equations (99) to (104) are shown in "Slope ax" and "Intercept bx". The diagnosis target value dts is set to -0.5 mm. The predicted value obtained from the above-mentioned equations (105) to (107) is shown in "Estimation". "Estimation - Data 2" shows the predicted value from "Data 2". In FIG. 40, from "Data 2", the diagnosis target value dts is reached after 8 days, operating time of 60 hours, or accumulated flow rate of 760 t.

[0442] (4-4-2. Effects) As described above, the timing prediction diagnostic process makes it possible to predict when a failure will occur or when maintenance or equipment replacement will be required. By having a history of calibration and diagnosis, the health of the equipment can be understood. By using the converter's operating time and integrated flow rate in addition to the time, a diagnosis that is close to reality can be performed. Corrosion occurs when a corrosive fluid is flowed, so the integrated flow rate is important. Converter failures are often affected by the operating time. By evaluating density error and flow rate error, it is possible to predict when flow rate calibration will be necessary. By storing the obtained diagnostic results in a history, the state of condition changes can be understood. This makes it possible to perform timing prediction diagnosis (life diagnosis). From multiple parameters, the parameter that suits the purpose can be used.

[0443] For users, predicting when maintenance or replacement is necessary is important for the effective use of equipment. Maintenance requires the equipment to be shut down and calibration costs are incurred. For equipment prone to failures such as corrosion, replacement must be anticipated.

[0444] [5. Flow of each process of the diagnostic device (2)] The flow of each process of the diagnosis device (2) according to the embodiment will be described with reference to Figures 41 to 47. Below, the flow of the entire diagnosis process, the flow of the stiffness damping diagnosis process, the flow of the wall thickness diagnosis process, the flow of the density error diagnosis and simple correction process, the flow of the flow rate error diagnosis and simple correction process, and the flow of the timing prediction diagnosis process will be described in this order.

[0445] (5-1. Overall flow of diagnostic processing) The overall flow of the diagnostic process will be described with reference to Fig. 41. Fig. 41 is a flowchart showing an example of the overall flow of the diagnostic process according to the embodiment. Note that the processes of steps S101 to S105 below may be executed in a different order. Also, some of the processes of steps S101 to S105 below may be omitted.

[0446] The diagnostic device (2) executes a stiffness damping diagnostic process (step S101), a wall thickness diagnostic process (step S102), a density error diagnostic process and simple correction process (step S103), a flow rate error diagnostic process and simple correction process (step S104), a timing prediction diagnostic process (step S105), and ends the process.

[0447] (5-2. Stiffness damping diagnosis process flow) The flow of the stiffness attenuation diagnosis process will be described with reference to Figs. 42 and 43. Fig. 42 is a flowchart showing an example of the flow of the stiffness attenuation diagnosis process according to the embodiment. Fig. 43 is a flowchart showing an example of the flow of the stiffness attenuation diagnosis process according to the embodiment. Below, the flow of the stiffness attenuation diagnosis process as a whole will be described, and then the flow of each process will be described. Note that the following processes can also be executed in a different order. Also, some of the following processes may be omitted.

[0448] (5-2-1. Overall flow of stiffness damping diagnosis process) 42, the diagnostic device (2) executes an execution determination process (steps S201 to S206), and if the initialization execution signal (223) is set (step S207: Yes), executes a stiffness damping measurement process (step S208), executes a stiffness damping initialization process (step S209), and ends the process. On the other hand, if the initialization execution signal (223) is not set (step S207: No), the diagnostic device (2) proceeds to the process of step S210.

[0449] If the judgment execution signal (224) is set (step S210: Yes), the diagnostic device (2) executes a stiffness damping measurement process (step S211), executes a stiffness damping judgment process (step S212), and ends the process. On the other hand, if the judgment execution signal (224) is not set (step S210: No), the diagnostic device (2) ends the process.

[0450] (5-2-2. Flow of execution decision process) As shown in Fig. 42, first, the diagnostic device (2) resets the initialization execution signal and the judgment execution signal (step S201). Next, the diagnostic device (2) judges whether the stiffness damping diagnosis execution signal (230) is set (step S202). At this time, if the stiffness damping diagnosis execution signal (230) is set (step S202: Yes), the diagnostic device (2) proceeds to the process of step S203. On the other hand, if the stiffness damping diagnosis execution signal (230) is not set (step S202: No), the diagnostic device (2) ends the process.

[0451] The diagnostic device (2) determines whether an initial value exists (step S203). At this time, if there is no initial value (step S203: Yes), the diagnostic device (2) sets an initialization execution signal (223) (step S205). On the other hand, if there is an initial value (step S203: No), the diagnostic device (2) proceeds to the process of step S204. Here, the diagnostic device (2) determines that there is no initial value when either the initial date and time (222x) has not been set or the initial stiffness Kc0 (222e) is a numerical value of 0.0.

[0452] The diagnostic device (2) judges whether an initial value acquisition command (222u) is set (step S204). At this time, the diagnostic device (2) indicates that it has determined that initialization is necessary. If the initial value acquisition command (222u) is set (step S204: Yes), the diagnostic device (2) sets an initialization execution signal (223) (step S205) and proceeds to processing from step S207 onwards. On the other hand, if the initial value acquisition command (222u) is not set (step S204: No), the diagnostic device (2) sets a judgment execution signal (224) (step S206) and proceeds to processing from step S207 onwards.

[0453] (5-2-3. Stiffness damping measurement process flow) 43, the stiffness damping measurement process will be described when DG1, which is the fixed drive gain (242), is smaller than the AGC drive gain (241) and DG2, which is the fixed drive gain (242), is larger than the AGC drive gain (241). Note that the amplitude S1 (27d) decreases and then increases.

[0454] First, the diagnostic device (2) sets the fixed drive gain (242) to DG1 (step S301). The diagnostic device (2) also sets the drive gain selection (240) to the fixed drive gain (242) (step S302). At this time, the diagnostic device (2) changes the drive gain selection (240) and outputs the fixed drive gain (242) from the drive gain selector (21f). The diagnostic device (2) also starts averaging the corrected frequency (225) and the temperature T (28e) (step S303). The diagnostic device (2) also starts averaging the gain Gc (step S304). At this time, the diagnostic device (2) calculates the gain Gc by the above formula (38).

[0455] Next, the diagnostic device (2) compares the amplitude S1 (27d) with the amplitude threshold ATH1 (step S305). At this time, if the amplitude S1 (27d) is greater than the amplitude threshold ATH1 (step S305: Yes), the diagnostic device (2) continues the process of step S305. On the other hand, if the amplitude S1 (27d) is equal to or less than the amplitude threshold ATH1 (step S305: No), the diagnostic device (2) records the time t1 and the amplitude Ax1 (step S306).

[0456] Next, the diagnostic device (2) compares the amplitude S1 (27d) with the amplitude threshold ATH2 (step S306). If the amplitude S1 (27d) is greater than the amplitude threshold ATH2 (step S305: Yes), the diagnostic device (2) continues the process of step S306. On the other hand, if the amplitude S1 (27d) is equal to or less than the amplitude threshold ATH2 (step S305: No), the diagnostic device (2) records the time t2 and the amplitude Ax2 (step S306).

[0457] Then, the diagnostic device (2) stores the average value of the gain Gc in GC1 (step S309), sets the fixed drive gain (242) to DG2 (step S310), starts averaging the gain Gc (step S311), and compares the amplitude S1 (27d) with the amplitude threshold ATH2 (step S312). At this time, if the amplitude S1 (27d) is smaller than the amplitude threshold ATH2 (step S312: Yes), the process of step S312 is continued, and if the amplitude S1 (27d) is equal to or larger than the amplitude threshold ATH2 (step S312: No), the time t3 and the amplitude Ax3 are recorded (step S313). Also, the diagnostic device (2) compares the amplitude S1 (27d) with the amplitude threshold ATH1 (step S314). At this time, if the amplitude S1 (27d) is smaller than the amplitude threshold ATH1 (step S314: Yes), the diagnostic device (2) continues the processing of step S314, and if the amplitude S1 (27d) is equal to or greater than the amplitude threshold ATH1 (step S314: No), the diagnostic device (2) records the time t4 and the amplitude Ax4 (step S315).

[0458] Then, the diagnostic device (2) stores the average value of the gain Gc in GC2 (step S316), stores the average value of the corrected frequency (225) in fc, and the average value of the temperature T (28e) in Tc (step S317), and sets the drive gain selection (240) to the AGC drive gain (241) (step S318).

[0459] The diagnostic device (2) also calculates the increase / decrease rates αx1 and αx2 using the above formula (35) and formula (36) (step S319). The diagnostic device (2) also calculates the correction coefficient Ct using the above formula (38) (step S320). The diagnostic device (2) also calculates the mass, stiffness, damping, and Q value (step S321). At this time, the diagnostic device (2) obtains the mass Mxd and mass Mxg from the above formula (39) and outputs them to the mass Mc (221d), obtains the stiffness Kxd and stiffness Kxg from the above formula (40) and outputs them to the stiffness Kc (221e), obtains the damping Dxd and damping Dxg from the above formula (41) and outputs them to the damping Dc (221f), and obtains the Q value Qxd and Qxg from the above formula (42) and outputs them to the Q value Qc (221g).

[0460] Finally, the diagnostic device (2) saves the diagnostic information (step S322) and ends the process. At this time, the diagnostic device (2) sets the date and time (28x) of the parameter (28) to the diagnosis date and time (221x), sets the conversion unit drive time (28y) of the parameter (28) to the drive time (221y), and sets the integrated flow rate (28z) of the parameter (28) to the integrated flow rate (221z).

[0461] (5-2-4. Stiffness damping initialization process flow) The diagnostic device (2) sets an initial value to the stiffness damping diagnosis setting value (222), resets an initial value acquisition command (222u), initializes the stiffness damping diagnosis result (221), sets an initialization flag (221t), sets an update flag (221s), resets a stiffness damping diagnosis execution signal (230), sets a stiffness damping diagnosis completion signal (231), and ends the process.

[0462] (5-2-5. Stiffness attenuation judgment process flow) The diagnostic device (2) calculates the rate of change, compares the rate of change with a tolerance, sets an abnormality determination value, resets an initialization flag (221t), sets an update flag (221s), resets a stiffness damping diagnosis execution signal (230), sets a stiffness damping diagnosis completion signal (231), and ends the process.

[0463] (5-3. Flow of thickness diagnosis process) The flow of the wall thickness diagnosis process will be described with reference to FIG. 44. FIG. 44 is a flowchart showing an example of the flow of the entire wall thickness diagnosis process according to the embodiment. Below, the flow of the entire wall thickness diagnosis process will be described, and then the flow of each process will be described. Note that each of the processes below can also be executed in a different order. Also, some of the processes below may be omitted.

[0464] (5-3-1. Overall flow of thickness diagnosis process) As shown in Fig. 44, the diagnostic device (2) executes an initialization determination process (steps S401 to S408), and if the initialization signal (306) is set (step S409: Yes), executes a thickness diagnosis initialization process (step S410), and ends the process. On the other hand, if the initialization signal (306) is not set (step S409: No), the diagnostic device (2) proceeds to the process of step S411.

[0465] If the diagnosis initialization signal (307) is set (step S411: Yes), the diagnosis device (2) executes a thickness calculation process (step S412), executes a thickness change initialization process (step S413), and ends the process. On the other hand, if the diagnosis initialization signal (307) is not set (step S411: No), the diagnosis device (2) proceeds to the process of step S414.

[0466] If the diagnosis execution signal (308) is set (step S414: Yes), the diagnosis device (2) executes a thickness calculation process (step S415), executes a thickness change determination process (step S416), and ends the process. On the other hand, if the diagnosis execution signal (308) is not set (step S414: No), the diagnosis device (2) ends the process.

[0467] (5-3-2. Flow of initialization determination process) As shown in Fig. 44, first, the diagnostic device (2) resets the initialization signal (306), the diagnosis initialization signal (307), and the diagnosis execution signal (308) (step S401). Next, the diagnostic device (2) judges whether the stiffness damping diagnosis completion signal (231) is set (step S402). At this time, if the stiffness damping diagnosis completion signal (231) is set (step S402: Yes), the diagnostic device (2) proceeds to the process of step S403, and if the stiffness damping diagnosis completion signal (231) is not set (step S402: No), the diagnostic device (2) ends the process.

[0468] The diagnostic device (2) determines whether an initial value exists (step S403). At this time, if there is no initial value (step S403: Yes), the diagnostic device (2) sets the initialization signal (306) (step S405). On the other hand, if there is an initial value (step S403: No), the diagnostic device (2) proceeds to the process of step S404. Here, the diagnostic device (2) determines that there is no initial value when either the initial inner diameter d0 (322a) is the numerical value 0 or the initial date and time (322x) has not been set.

[0469] The diagnostic device (2) determines whether the initialization flag (221t) is set (step S404). If the initialization flag (221t) is set (step S404: Yes), the diagnostic device (2) sets the initialization signal (306) (step S405). On the other hand, if the initialization flag (221t) is not set (step S404: No), the diagnostic device (2) proceeds to the process of step S406.

[0470] The diagnostic device (2) determines whether the initialization execution command (322u) is set (step S406). At this time, if the initialization execution command (322u) is set (step S406: Yes), the diagnostic initialization signal (307) is set (step S407), and the process proceeds to step S409 and thereafter. On the other hand, if the initialization execution command (322u) is not set (step S406: No), the diagnostic device (2) sets the diagnosis execution signal (308) (step S408), and the process proceeds to step S409 and thereafter.

[0471] (5-3-3. Flow of Initialization Process for Wall Thickness Diagnosis) The diagnosis device (2) sets an initial value to the wall thickness diagnosis set value (322), resets the initialization execution command (322u), initializes the wall thickness diagnosis result (321), sets the initialization flag (321t), sets the update flag (321s), resets the stiffness damping diagnosis completion signal (231), sets the wall thickness diagnosis completion signal (331), and ends the process.

[0472] (5-3-4. Flow of thickness calculation process) The diagnosis device (2) calculates the wall thickness change rate, sets it as the wall thickness diagnosis result (321), sets the stiffness attenuation diagnosis result (221) as the wall thickness diagnosis result (321), and ends the process.

[0473] (5-3-5. Flow of wall thickness change initialization process) The diagnosis device (2) sets an initial value of the wall thickness diagnosis set value (322), resets the initialization execution command (322u), initializes the wall thickness diagnosis result (321), sets the initialization flag (321t), sets the update flag (321s), resets the stiffness damping diagnosis completion signal (231), sets the wall thickness diagnosis completion signal (331), and ends the process.

[0474] (5-3-6. Flow of thickness change determination process) The diagnosis device (2) compares the wall thickness diagnosis result (321) with the wall thickness diagnosis set value (322), sets an abnormality determination value in the wall thickness diagnosis result (321), resets the initialization flag (321t), sets the update flag (321s), resets the stiffness damping diagnosis completion signal (231), sets the wall thickness diagnosis completion signal (331), and ends the process.

[0475] (5-4. Density error diagnosis and simple correction process flow) The flow of density error diagnosis and simple correction processing will be described with reference to FIG. 45. FIG. 45 is a flowchart showing an example of the overall flow of density error diagnosis and simple correction processing according to the embodiment. Below, the overall flow of density error diagnosis and simple correction processing will be described, and then the flow of each process will be described. Note that the following processes can also be executed in a different order. Also, some of the following processes may be omitted.

[0476] (5-4-1. Overall flow of density error diagnosis and simple correction process) As shown in Fig. 45, first, the diagnostic device (2) executes an initialization determination process (steps S501 to S509), and if the initialization execution signal 1 (407) is set (step S510: Yes), it executes a density initialization process (step S511) and ends the process. On the other hand, if the initialization execution signal 1 (407) is not set (step S510: No), the diagnostic device (2) proceeds to the process of step S512.

[0477] If the initialization execution signal 2 (408) is set (step S512: Yes), the diagnostic device (2) executes the rigidity / thickness initialization process (step S513) and ends the process. On the other hand, if the initialization execution signal 2 (408) is not set (step S512: No), the diagnostic device (2) proceeds to the process of step S514.

[0478] If the update execution signal (409) is set (step S514: Yes), the diagnostic device (2) executes the density correction coefficient update process (step S515) and ends the process. On the other hand, if the update execution signal (409) is not set (step S514: No), the diagnostic device (2) ends the process.

[0479] (5-4-2. Flow of initialization determination process) As shown in FIG. 45, first, the diagnostic device (2) resets the initialization execution signal 1 (407), the initialization execution signal 2 (408), and the update execution signal (409) (step S501). Next, the diagnostic device (2) determines whether the density calibration completion signal (122) is set (step S502). Here, the density calibration completion signal (122) is set when the density calibration process is executed by the density calibration unit (51) of the calibration device (3). At this time, if the density calibration completion signal (122) is set (step S502: Yes), the diagnostic device (2) sets the initialization execution signal 1 (407) (step S503) and proceeds to the process of step S510 and subsequent steps. On the other hand, if the density calibration completion signal (122) is not set (step S502: No), the diagnostic device (2) proceeds to the process of step S504.

[0480] The diagnosis device (2) determines whether the wall thickness diagnosis completion signal (331) is set (step S504). If the wall thickness diagnosis completion signal (331) is set (step S504: Yes), the process proceeds to step S505. If the wall thickness diagnosis completion signal (331) is not set (step S504: No), the process ends. Here, the wall thickness diagnosis completion signal (331) is set when the wall thickness diagnosis process is executed by the wall thickness diagnosis unit (70).

[0481] The diagnostic device (2) determines whether an initial value exists (step S505). Here, the diagnostic device (2) determines whether an initial date and time (422x) is set. At this time, if an initial value does not exist (step S505: Yes), the diagnostic device (2) sets the initialization execution signal 2 (408) (step S508) and proceeds to processing from step S510 onwards. On the other hand, if an initial value exists (step S505: No), the diagnostic device (2) proceeds to processing of step S506.

[0482] The diagnostic device (2) determines whether the initialization flag (321t) is set (step S506). At this time, if the initialization flag (321t) is set (step S506: Yes), the diagnostic device (2) sets the initialization execution signal 2 (408) (step S508) and proceeds to processing of step S510 and thereafter. On the other hand, if the initialization flag (321t) is not set (step S506: No), the diagnostic device (2) proceeds to processing of step S507.

[0483] The diagnostic device (2) determines whether the initialization execution command (422u) is set (step S507). At this time, if the initialization execution command (422u) is set (step S507: Yes), the diagnostic device (2) sets the initialization execution signal 2 (408) (step S508) and proceeds to processing from step S510 onwards. On the other hand, if the initialization execution command (422u) is not set (step S507: No), the diagnostic device (2) sets the update execution signal (409) (step S509) and proceeds to processing from step S510 onwards.

[0484] (5-4-3. Density initialization process flow) The diagnostic device (2) initializes the density diagnosis set value (422), sets an initialization execution command (422u), initializes the density diagnosis result (421), sets an initialization flag (421t), sets an update flag (421s), resets the density calibration completion signal (122), sets a density diagnosis completion signal (431), and ends the process.

[0485] (5-4-4. Flow of stiffness and thickness initialization process) The diagnostic device (2) initializes the density diagnosis set value (422), resets the initialization execution command (422u), initializes the density diagnosis result (421), sets the initialization flag (421t), sets the update flag (421s), resets the thickness diagnosis completion signal (331), sets the density diagnosis completion signal (431), and ends the process.

[0486] (5-4-5. Density correction coefficient update process flow) The diagnostic device (2) sets the measurement information of the density diagnosis result (421) and calculates the density measurement coefficient, coefficient change rate, density fluctuation, and density error. At this time, if the absolute value of the density fluctuation Δρ (421e) is greater than the density fluctuation allowable value (422h), the diagnostic device (2) sets the density coefficient selection signal (404) and updates the density measurement coefficient Cd (28k) and the density measurement coefficient fa (28l). Also, if the absolute value of the density error Δρ0 (421f) is greater than the density error alarm value (422r), the diagnostic device (2) sets a density diagnosis abnormality (421r). On the other hand, if the absolute value of the density error Δρ0 (421f) is smaller than the density error alarm value (422r), the diagnostic device (2) resets the density diagnosis abnormality (421r).

[0487] The diagnostic device (2) resets the initialization flag (421t), sets the update flag (421s), resets the thickness diagnosis completion signal (331), sets the density diagnosis completion signal (431), and ends the process.

[0488] (5-5. Flow rate error diagnosis and simple correction process flow) The flow of the flow error diagnosis and simple correction process will be described with reference to FIG. 46. FIG. 46 is a flowchart showing an example of the overall flow of the flow error diagnosis and simple correction process according to the embodiment. Below, the overall flow of the flow error diagnosis and simple correction process will be described, and then the flow of each process will be described. Note that each of the processes below can also be executed in a different order. Also, some of the processes below may be omitted.

[0489] (5-5-1. Overall flow of flow rate error diagnosis and simple correction process) As shown in Fig. 46, first, the diagnostic device (2) executes an initialization determination process (steps S601 to S609), and if the initialization execution signal 1 (507) is set (step S610: Yes), it executes a flow rate initialization process (step S611) and ends the process. On the other hand, if the initialization execution signal 1 (507) is not set (step S610: No), the diagnostic device (2) proceeds to the process of step S612.

[0490] If the initialization execution signal 2 (508) is set (step S612: Yes), the diagnostic device (2) executes the rigidity / thickness initialization process (step S613) and ends the process. On the other hand, if the initialization execution signal 2 (508) is not set (step S612: No), the diagnostic device (2) proceeds to the process of step S614.

[0491] If the update execution signal (509) is set (step S614: Yes), the diagnostic device (2) executes the flow rate correction coefficient update process (step S615) and ends the process. On the other hand, if the update execution signal (509) is not set (step S614: No), the diagnostic device (2) ends the process.

[0492] (5-5-2. Flow of initialization determination process) As shown in FIG. 46, first, the diagnostic device (2) resets the initialization execution signal 1 (507), the initialization execution signal 2 (508), and the update execution signal (509) (step S601). Next, the diagnostic device (2) determines whether the flow rate calibration completion signal (121) is set (step S602). Here, the flow rate calibration completion signal (121) is set when the mass flow rate calibration process is executed by the mass flow rate calibration unit (41) of the calibration device (3). At this time, if the flow rate calibration completion signal (121) is set (step S602: Yes), the diagnostic device (2) sets the initialization execution signal 1 (507) (step S603) and proceeds to the process of step S610 and subsequent steps. On the other hand, if the flow rate calibration completion signal (121) is not set (step S602: No), the diagnostic device (2) proceeds to the process of step S604.

[0493] The diagnostic device (2) determines whether the density diagnosis completion signal (431) is set (step S604). If the density diagnosis completion signal (431) is set (step S604: Yes), the process proceeds to step S605. If the density diagnosis completion signal (431) is not set (step S604: No), the process ends. Here, the density diagnosis completion signal (431) is set when the density error diagnosis and simple correction process is executed by the density error diagnosis simple correction unit (80).

[0494] The diagnostic device (2) determines whether an initial value exists (step S605). Here, the diagnostic device (2) determines whether an initial date and time (522x) has been set. At this time, if an initial value does not exist (step S605: Yes), the diagnostic device (2) sets the initialization execution signal 2 (508) (step S608) and proceeds to processing from step S610 onwards. On the other hand, if an initial value exists (step S605: No), the diagnostic device (2) proceeds to processing of step S606.

[0495] The diagnostic device (2) determines whether the initialization flag (321t) or the initialization flag (421t) is set (step S606). At this time, if the initialization flag (321t) or the initialization flag (421t) is set (step S606: Yes), the diagnostic device (2) sets the initialization execution signal 2 (508) (step S608) and proceeds to processing of step S610 and thereafter. On the other hand, if neither the initialization flag (321t) nor the initialization flag (421t) is set (step S606: No), the diagnostic device (2) proceeds to processing of step S607.

[0496] The diagnostic device (2) determines whether the initialization execution command (522u) is set (step S607). At this time, if the initialization execution command (522u) is set (step S607: Yes), the diagnostic device (2) sets the initialization execution signal 2 (508) (step S608) and proceeds to processing from step S610 onwards. On the other hand, if the initialization execution command (522u) is not set (step S607: No), the diagnostic device (2) sets the update execution signal (509) (step S609) and proceeds to processing from step S610 onwards.

[0497] (5-5-3. Flow Initialization Process) The diagnostic device (2) initializes the flow rate diagnosis set value (522), sets an initialization execution command (522u), sets the flow rate correction coefficient fk (28u) to an initial value of 1.0, initializes the flow rate diagnosis result (521), sets an initialization flag (521t), sets an update flag (521s), resets the flow rate calibration completion signal (121), and ends the process.

[0498] (5-5-4. Flow of stiffness and thickness initialization process) The diagnostic device (2) initializes the flow rate diagnosis set value (522), resets the initialization execution command (522u), sets the flow rate correction coefficient fk (28u) to an initial value of 1.0, initializes the flow rate diagnosis result (521), sets the initialization flag (501t), sets the update flag (521s), resets the density diagnosis completion signal (431), and ends the process.

[0499] (5-5-5. Flow rate correction coefficient update process flow) The diagnostic device (2) calculates the flow correction coefficient, the flow error rate, and the flow rate fluctuation rate. At this time, if the absolute value of the flow rate fluctuation rate rqd (521c) is greater than the flow rate fluctuation allowable value (522h), the diagnostic device (2) sets the flow coefficient selection signal (504) and sets the flow correction coefficient fk (28u). Furthermore, if the absolute value of the flow rate error rate rqe (521b) is greater than the flow rate error alarm value (522r), the diagnostic device (2) sets a flow rate diagnosis abnormality (521r). On the other hand, if the absolute value of the flow rate error rate rqe (521b) is equal to or less than the flow rate error alarm value (522r), the diagnostic device (2) resets the flow rate diagnosis abnormality (521r).

[0500] The diagnostic device (2) resets the initialization flag (521t), sets the update flag (521s), resets the density diagnosis completion signal (431), and ends the process.

[0501] (5-6. Flow of timing prediction diagnosis process) The flow of the timing prediction diagnosis process will be described with reference to Fig. 47. Fig. 47 is a flowchart showing an example of the flow of the entire timing prediction diagnosis process according to the embodiment. Note that the processes of S701 to S705 below can also be executed in a different order. Also, some of the processes of S701 to S705 below may be omitted.

[0502] The diagnostic device (2) determines whether an update flag is set (step S701). At this time, if an update flag is set (step S701: Yes), the diagnostic device (2) proceeds to the process of step S702. On the other hand, if none of the update flags are set (step S701: No), the diagnostic device (2) ends the process. Note that the update flag of the diagnostic data is included in each diagnostic result.

[0503] The diagnostic device (2) checks the stiffness damping diagnostic result (221), the wall thickness diagnostic result (321), the density diagnostic result (421), and the flow rate diagnostic result (521), imports the diagnostic result data (step S702), calculates a change trend value (601) from the imported data (step S703), calculates a timing prediction diagnostic result (603) from the change trend value (601) and the diagnostic target value (602) (step S704), resets the update flag (step S705), and ends the process.

[0504] 6. Effects of the embodiment Finally, effects of the embodiment will be described below: Effects 1 to 8 corresponding to the processing according to the embodiment will be described below.

[0505] (6-1. Effect 1) In the process according to the embodiment described above, a driving force with a constant oscillation feedback gain is applied to the vibrating tube (11) in the Coriolis mass flowmeter (1), which measures the flow rate and density of a fluid flowing through the vibrating tube (11) based on the Coriolis force acting on the vibrated vibrating tube (11), to generate a stiffness damping diagnosis result (221) relating to a stiffness change in the vibrating tube (11), and a calculation is performed on the thickness of the vibrating tube (11) based on the stiffness damping diagnosis result (221) to generate a thickness diagnosis result (321) relating to a thickness change in the vibrating tube (11). Therefore, in this process, the state of the vibrating tube (11) of the Coriolis mass flowmeter (1) can be accurately diagnosed.

[0506] (6-2. Effect 2) In the process according to the embodiment described above, a thickness diagnosis result (321) including at least one of the inner diameter, thickness, thickness change, and thickness change rate of the vibration pipe (11) is generated using the stiffness change rate of the vibration pipe (11) indicated by the stiffness damping diagnosis result (221) and the design value of the vibration pipe (11), and an abnormality related to the vibration pipe (11) is detected when the thickness diagnosis result (321) is equal to or greater than a threshold value. Therefore, in this process, the thickness diagnosis result (321) is effectively generated, thereby making it possible to accurately diagnose the state of the vibration pipe (11) of the Coriolis mass flowmeter (1).

[0507] (6-3. Effect 3) In the process according to the embodiment described above, a calculation related to the density of the fluid is performed based on the wall thickness diagnosis result (321) to generate a density diagnosis result (421) related to a density error of the fluid. Therefore, in this process, by generating the density diagnosis result (421), it is possible to accurately diagnose the condition of the vibrating tube (11) of the Coriolis mass flowmeter (1).

[0508] (6-4. Effect 4) In the process according to the embodiment described above, a density measurement coefficient is calculated using the results related to the stiffness change and the wall thickness change, and based on the calculated density measurement coefficient, update control of the density measurement coefficient used by the Coriolis mass flowmeter (1) to measure density is performed. Therefore, in this process, by effectively generating a density diagnosis result (421), it is possible to accurately diagnose the state of the vibrating tube (11) of the Coriolis mass flowmeter (1) and perform simple correction related to density.

[0509] (6-5. Effect 5) In the process according to the embodiment described above, a calculation related to the flow rate of the fluid is performed based on the density diagnosis result (421) to generate a flow rate diagnosis result (521) related to the flow rate error of the fluid. Therefore, in this process, by generating the flow rate diagnosis result (521), it is possible to accurately diagnose the condition of the vibrating tube (11) of the Coriolis mass flowmeter (1).

[0510] (6-6. Effect 6) In the process according to the present embodiment described above, a flow rate correction coefficient is calculated using at least one of the stiffness change rate, the wall thickness change rate, and the change rate of the density measurement coefficient, and update control of the flow rate correction coefficient used by the Coriolis mass flowmeter (1) to measure the flow rate is performed based on the calculated flow rate correction coefficient. Therefore, in this process, by effectively generating a flow rate diagnosis result (521), it is possible to accurately diagnose the state of the vibrating tube (11) of the Coriolis mass flowmeter (1) and perform simple correction related to the flow rate.

[0511] (6-7. Effect 7) In the process according to the present embodiment described above, the occurrence of a fault in the Coriolis mass flowmeter (1), the time required for maintenance or equipment replacement, the operating time, or the integrated flow rate of the fluid are predicted based on the stiffness damping diagnosis result (221), the wall thickness diagnosis result (321), the density diagnosis result (421), or the flow rate diagnosis result (521), and output as a timing prediction diagnosis result (603). Therefore, in this process, the condition of the vibrating tube (11) of the Coriolis mass flowmeter (1) can be accurately diagnosed, and the diagnosis result can be effectively utilized.

[0512] (6-8. Effect 8) In the process according to the present embodiment described above, when the stiffness damping diagnosis result (221), the wall thickness diagnosis result (321), the density diagnosis result (421), or the flow rate diagnosis result (521) exceeds a predetermined alarm value, an abnormality related to the vibrating tube (11) is notified. Therefore, in this process, the condition of the vibrating tube (11) of the Coriolis mass flowmeter (1) can be accurately diagnosed, and the diagnosis result can be effectively utilized to provide useful information.

[0513] 〔system〕 The information including the processing procedures, control procedures, specific names, various data and parameters shown in the above documents and drawings can be changed arbitrarily unless otherwise specified.

[0514] In addition, each component of each device shown in the figure is a functional concept, and does not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure. In other words, all or part of them can be functionally or physically distributed and integrated in any unit according to various loads, usage conditions, etc.

[0515] Furthermore, each processing function performed by each device may be realized, in whole or in part, by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware using wired logic.

[0516] [Hardware] Next, an example of the hardware configuration of the diagnostic device (2) will be described. Note that other devices may have a similar hardware configuration. FIG. 48 is a diagram for explaining an example of the hardware configuration. As shown in FIG. 48, the diagnostic device (2) has a communication device (2a), a HDD (Hard Disk Drive) (2b), a memory (2c), and a processor (2d). In addition, each unit shown in FIG. 48 is connected to each other by a bus or the like.

[0517] The communication device (2a) is a network interface card or the like, and communicates with other servers. The HDD (2b) stores the programs and DB that operate the functions shown in FIG.

[0518] The processor (2d) reads out a program that executes the same processing as each processing unit shown in FIG. 4 from the HDD (2b) or the like and loads it in the memory (2c), thereby operating a process that executes each function described in FIG. 4 or the like. For example, this process executes the same function as each processing unit of the diagnosis device (2). Specifically, the processor (2d) reads out a program having the same function as the stiffness damping diagnosis unit (61), the wall thickness diagnosis unit (70), the density error diagnosis simple correction unit (80), the flow rate error diagnosis simple correction unit (90), the timing prediction diagnosis unit (100), or the like from the HDD (2b) or the like. Then, the processor (2d) executes a process that executes the same processing as the stiffness damping diagnosis unit (61), the wall thickness diagnosis unit (70), the density error diagnosis simple correction unit (80), the flow rate error diagnosis simple correction unit (90), the timing prediction diagnosis unit (100), or the like.

[0519] In this way, the diagnostic device (2) operates as an information processing device that executes various processing methods by reading and executing the programs. The diagnostic device (2) can also realize functions similar to those of the above-mentioned embodiment by reading the above programs from a recording medium using a media reading device and executing the read programs. Note that the programs in these other embodiments are not limited to being executed by the diagnostic device (2). For example, the present invention can be similarly applied to cases where other computers or servers execute the programs, or where these execute the programs in cooperation with each other.

[0520] This program can be distributed via a network such as the Internet. This program can also be recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, a magneto-optical disk (MO), or a digital versatile disk (DVD), and can be executed by being read out from the recording medium by a computer. [Explanation of symbols]

[0521] 1 Coriolis mass flowmeter 2. Diagnostic equipment 3 Calibration device 10. Detection section 11 Vibration tube 20 Conversion unit 21 Drive control unit 22 Mass flow rate calculation section 23 Density calculation section 30 Display operation section 31 External device 40 Calibration control section 41 Mass flow rate calibration section 51 Density calibration section 60 Diagnostic control unit 61 Rigidity Diagnosis Department 70 Thickness Diagnosis Section 80 Density error simple correction section 90 Flow rate error simple correction section 100 Time Prediction and Diagnosis Department 200 Transmitter / receiver 300 Notification Department 1000 Diagnostic Systems

Claims

1. a stiffness damping diagnostic unit that applies a driving force with a constant oscillation feedback gain to a Coriolis mass flowmeter that measures a flow rate and density of a fluid flowing through a vibrating tube based on a Coriolis force acting on the vibrating tube, and generates a stiffness damping diagnostic result related to a stiffness change of the vibrating tube; a thickness diagnosis unit that performs calculations regarding a thickness of the vibration pipe based on the stiffness damping diagnosis result and generates a thickness diagnosis result regarding a change in the thickness of the vibration pipe; A diagnostic device comprising:

2. The thickness diagnostic unit includes: generating a thickness diagnosis result including at least one of an inner diameter, a wall thickness, a wall thickness change, and a wall thickness change rate of the vibration pipe using a stiffness change rate of the vibration pipe indicated by the stiffness damping diagnosis result and a design value of the vibration pipe; When the wall thickness diagnosis result is equal to or greater than a threshold value, an abnormality related to the vibration pipe is detected. The diagnostic device of claim 1 .

3. a density error diagnosis simple correction unit that performs calculations regarding the density of the fluid based on the wall thickness diagnosis result and generates a density diagnosis result regarding a density error of the fluid; The diagnostic device of claim 1 further comprising:

4. The density error diagnosis and simple correction unit includes: Calculating a density measurement coefficient using the results relating to the stiffness change and the wall thickness change; and performing update control of a density measurement coefficient used by the Coriolis mass flowmeter to measure the density based on the calculated density measurement coefficient. The diagnostic device of claim 3.

5. a flow rate error diagnosis simple correction unit that performs a calculation regarding a flow rate of the fluid based on the density diagnosis result and generates a flow rate diagnosis result regarding a flow rate error of the fluid; The diagnostic device of claim 3 further comprising:

6. The flow rate error diagnosis simple correction unit includes: Calculating a flow rate correction coefficient using at least one of a stiffness change rate, a wall thickness change rate, and a density measurement coefficient change rate of the vibration pipe; and executing update control of a flow rate correction coefficient used by the Coriolis mass flowmeter to measure the flow rate based on the calculated flow rate correction coefficient. The diagnostic device according to claim 5.

7. a timing prediction diagnosis unit that predicts the occurrence of a fault in the Coriolis mass flowmeter, the time required for maintenance or equipment replacement, the operating time, or the integrated flow rate of the fluid based on the stiffness damping diagnosis result, the wall thickness diagnosis result, the density diagnosis result, or the flow rate diagnosis result, and outputs the result as a timing prediction diagnosis result; The diagnostic device of claim 5 further comprising:

8. a notification unit that notifies an abnormality related to the vibration pipe when the stiffness damping diagnosis result, the wall thickness diagnosis result, the density diagnosis result, or the flow rate diagnosis result exceeds a predetermined alarm value; The diagnostic device of claim 7 further comprising:

9. The computer a Coriolis mass flowmeter that measures a flow rate and density of a fluid flowing through a vibrating tube based on a Coriolis force acting on the vibrating tube, applying a driving force with a constant oscillation feedback gain to the vibrating tube to generate a stiffness damping diagnostic result related to a stiffness change of the vibrating tube; Executing a calculation regarding a wall thickness of the vibration tube based on the stiffness damping diagnosis result, and generating a wall thickness diagnosis result regarding a change in wall thickness of the vibration tube. A diagnostic method to perform the action.

10. On the computer, a Coriolis mass flowmeter that measures a flow rate and density of a fluid flowing through a vibrating tube based on a Coriolis force acting on the vibrating tube, applying a driving force with a constant oscillation feedback gain to the vibrating tube to generate a stiffness damping diagnostic result related to a stiffness change of the vibrating tube; Executing a calculation regarding a wall thickness of the vibration tube based on the stiffness damping diagnosis result, and generating a wall thickness diagnosis result regarding a change in wall thickness of the vibration tube. A diagnostic program that performs the process.

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