Diagnostic device

Abstract

To output a signal indicating an appropriate vibration value of each of a plurality of steam traps.SOLUTION: A diagnostic device comprises: a sensor for outputting an analog signal indicating vibration of an object steam trap that is a steam trap to be diagnosed; an amplifier circuit for amplifying an output signal of the sensor; a setting unit for setting a gain when the amplifier circuit amplifies the output signal of the sensor; an AD converter for converting an output signal of the amplifier circuit into a digital signal; and an adjustment unit for making the setting unit decrease or increase the gain until detecting that the AD converter does not overflow when detecting that the AD converter overflows, and outputting an output signal of the AD converter when detecting that the AD converter does not overflow.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for measuring vibrations of a steam trap. [Background technology]

[0002] In plants equipped with steam piping systems, condensate (drain) may occur within the piping system due to heat exchange or heat radiation. If this condensate remains within the piping system, it will cause a decrease in operating efficiency. For this reason, steam traps are generally installed in appropriate locations within the piping system, and the condensate is discharged outside the piping system using these steam traps.

[0003] If the sealing performance of a steam trap is impaired due to aging or malfunction, steam in the steam piping system will leak to the outside through the steam trap, resulting in unnecessary steam loss. For this reason, it has been customary to periodically, such as once a year, measure the vibration of each of multiple steam traps using a diagnostic device such as that disclosed in Patent Document 1, and diagnose each steam trap based on the vibration values ​​of the measurement results and the vibration characteristics of each steam trap. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-84418 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when diagnosing multiple steam traps using a single diagnostic device, depending on the usage conditions of the steam traps, the vibration of the steam traps may exceed the range that the diagnostic device can measure, causing the diagnostic device to overflow. In this case, the diagnostic device is unable to measure the appropriate vibration value of the steam trap, resulting in the problem of being unable to properly diagnose the steam traps.

[0006] The present invention has been made in view of the above circumstances, and has an object to provide a diagnostic device that can output signals that indicate appropriate vibration values ​​for each of a plurality of steam traps. [Means for solving the problem]

[0007] A diagnostic device according to one aspect of the present invention is a diagnostic device for diagnosing multiple steam traps, and includes: a sensor that outputs an analog signal indicating vibration of a target steam trap, which is the steam trap to be diagnosed; an amplifier circuit that amplifies the output signal of the sensor; a setting unit that sets the gain by which the amplifier circuit amplifies the output signal of the sensor; an AD converter that converts the output signal of the amplifier circuit into a digital signal; and an adjustment unit that, when it detects that the AD converter is overflowing, causes the setting unit to decrease or increase the gain until it detects that the AD converter is not overflowing, and outputs the output signal of the AD converter when it detects that the AD converter is not overflowing.

[0008] Depending on the usage conditions of the steam trap, the level of the signal obtained by amplifying an analog signal indicating the vibration of the steam trap in an amplifier circuit may exceed the range of analog signal levels that can be converted to a digital signal in an AD converter, causing the AD converter to overflow.

[0009] However, according to this aspect, if the AD converter is overflowing, the gain is decreased or increased until the AD converter no longer overflows, so that the AD converter can convert the analog signal indicating the vibration of the target steam trap into an appropriate digital signal. As a result, this aspect can designate each of the multiple steam traps as the target steam trap to be diagnosed, and output the output signal of the AD converter as a signal indicating the appropriate vibration value of the target steam trap.

[0010] In the above aspect, the adjustment unit may detect that the AD converter is overflowing when the value indicated by the output signal of the AD converter is equal to a predetermined upper limit value or when the value indicated by the output signal of the AD converter is less than a predetermined lower limit value that is smaller than the upper limit value.

[0011] According to this aspect, when the AD converter converts the output signal of the amplifier circuit into a digital signal indicating a value equal to a predetermined upper limit value or a value less than a predetermined lower limit value that is smaller than the upper limit value, it is possible to properly detect that the AD converter is overflowing.

[0012] In the above aspect, the plurality of steam traps are classified into a plurality of types of steam traps, and each type of steam trap is classified into a plurality of models of steam traps, including a first steam trap of a predetermined reference model and a second steam trap of a model different from the reference model, and the setting unit may set, as the initial value of the gain, the product of a predetermined reference gain and a ratio of the vibration value when vibration saturates in the first steam trap of a predetermined reference model to the vibration value when vibration saturates in the first steam trap of the same model as the target steam trap.

[0013] In this aspect, the initial value of the gain is set to the product of the ratio of the vibration value when vibration saturates in a first steam trap of a reference type to the vibration value when vibration saturates in a first steam trap of the same type as the target steam trap, and the reference gain.

[0014] Therefore, in this embodiment, when the AD converter does not overflow, an analog signal indicating the vibration of the target steam trap can be converted into a digital signal with the same accuracy as when an analog signal indicating the vibration of a reference type first steam trap is amplified by a reference gain and converted into a digital signal.

[0015] In the above aspect, the system may further include an amplifier unit that amplifies the output signal of the AD converter using an amplification factor that is a model correction coefficient that is the ratio of the vibration value of a second vibration characteristic that indicates the relationship between the steam leakage amount and vibration value of a first steam trap of the same model as the target steam trap to the vibration value of a first vibration characteristic that indicates the relationship between the steam leakage amount and vibration value of the target steam trap, a conversion unit that converts the vibration value of the target steam trap indicated by the output signal of the amplifier unit into the steam leakage amount of the target steam trap, and an output unit that outputs the steam leakage amount of the target steam trap.

[0016] The inventors compared the vibration characteristics of a first steam trap of the same model as the target steam trap with the vibration characteristics of the target steam trap when the steam leakage rate was the same. As a result, the inventors found that the ratio of the vibration values ​​of the first steam trap of the same model to the vibration values ​​of the target steam trap was constant regardless of the steam leakage rate.

[0017] In this aspect, the initial gain value is set to the product of the ratio of the vibration value at which vibration saturates in a first steam trap of a reference model to the vibration value at which vibration saturates in a first steam trap of the same model as the target steam trap, and the reference gain. The amplifier amplifies the output signal of the AD converter using a model correction coefficient, which is the ratio of the vibration value of the second vibration characteristic to the vibration value of the first vibration characteristic, as an amplification factor. The vibration value of the target steam trap indicated by the output signal from the amplifier is then converted into the steam leakage rate of the target steam trap.

[0018] Therefore, in this embodiment, in a situation where the AD converter does not overflow, an analog signal indicating the vibration of a reference type first steam trap is converted into a digital signal by amplifying it with a reference gain, and the vibration value of the reference type first steam trap indicated by the digital signal can be converted into a steam leakage amount with the same accuracy as when the vibration value of the target steam trap is converted into a steam leakage amount based on the vibration characteristics of the reference type first steam trap.

[0019] In the above aspect, the present invention may further include a correction unit that, when the conversion unit detects that an overflow has occurred, causes the setting unit to decrease or increase the gain until the conversion unit detects that an overflow has not occurred.

[0020] The steam trap is then fed to the steam generator, where it is connected to the power supply and the power amplifier, and the power amplifier is connected to the power supply.

[0021] In the above aspect, when the correction unit has caused the setting unit to reduce the gain until it detects that the conversion unit is not overflowing, it may further increase the amplification factor to the maximum extent possible within a range in which the conversion unit does not overflow, and when the correction unit has caused the setting unit to increase the gain until it detects that the conversion unit is not overflowing, it may further decrease the amplification factor to the maximum extent possible within a range in which the conversion unit does not overflow.

[0022] According to this aspect, when the converter overflows, the gain is reduced until the converter no longer overflows, and then the amplification factor is increased to the maximum extent within the range in which the converter does not overflow. Alternatively, the gain is increased until the converter no longer overflows, and then the amplification factor is reduced to the maximum extent within the range in which the converter does not overflow. Therefore, this aspect can convert the vibration value into the steam leakage amount in the converter with as high accuracy as possible while avoiding overflow of the converter.

[0023] In the above aspect, the correction unit may detect that the conversion unit is overflowing when the conversion unit converts the vibration value indicated by the input signal of the conversion unit into a steam leakage amount that is greater than the upper limit amount that can be converted in the conversion unit for a predetermined number of consecutive times, and when the conversion unit converts the vibration value indicated by the input signal of the conversion unit into a steam leakage amount that is less than the lower limit amount that can be converted in the conversion unit for a predetermined number of consecutive times.

[0024] According to this configuration, when the conversion unit converts the vibration value indicated by the input signal of the conversion unit into a steam leakage amount that is above the upper limit amount or below the lower limit amount that can be converted by the conversion unit a predetermined number of times in succession, it can properly detect that the conversion unit is overflowing.

[0025] In the above aspect, when a second leakage amount, which is the amount of steam leakage when vibration saturates in the first steam trap of the same model as the target steam trap, is smaller than a first leakage amount, which is the amount of steam leakage when vibration saturates in the first steam trap of the reference model, the setting unit may set the initial value of the gain to the product of the reciprocal of the ratio of the first leakage amount to the second leakage amount and the reference gain.

[0026] According to this configuration, when the second leakage amount is smaller than the first leakage amount, a gain smaller than the reference gain, which is the product of the ratio of the second leakage amount to the first leakage amount and the reference gain, is set as the initial value of the gain.

[0027] Therefore, in this embodiment, when the AD converter does not overflow, an analog signal indicating the vibration value of the target steam trap can be converted into a digital signal with the same accuracy as when an analog signal indicating the vibration of a reference type first steam trap is amplified by a reference gain and converted into a digital signal.

[0028] In the above aspect, when the target steam trap is the second steam trap, the conversion unit may convert the vibration value of the target steam trap indicated by the output signal of the amplification unit into the steam leakage amount of the target steam trap based on the second vibration characteristic and the model correction coefficient.

[0029] According to this configuration, when the target steam trap is the second steam trap, the first vibration characteristic, which is the vibration characteristic of the target steam trap, can be calculated by multiplying the second vibration characteristic by the inverse of the model correction coefficient, so that the vibration value of the target steam trap indicated by the output signal of the amplifier unit can be accurately converted into the steam leakage amount corresponding to that vibration value.

[0030] In the above aspect, when the target steam trap is the second steam trap, the conversion unit may convert the vibration value of the target steam trap indicated by the output signal of the amplification unit into the steam leakage amount of the target steam trap based on a function that linearly approximates the second vibration characteristic and the model correction coefficient.

[0031] According to this configuration, when the target steam trap is the second steam trap, the vibration value of the target steam trap indicated by the output signal of the amplifier can be converted into the steam leakage rate corresponding to the vibration value using a function that linearly approximates the first vibration characteristic, which is the vibration characteristic of the target steam trap, and is indicated by the product of a function that linearly approximates the second vibration characteristic and the inverse of the model correction coefficient. This simplifies the conversion unit. [Effects of the Invention]

[0032] According to the present invention, it is possible to provide a diagnostic device that can output signals that indicate appropriate vibration values ​​for each of a plurality of steam traps. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a block diagram showing a configuration of a diagnostic device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a diagram illustrating an example of a management ledger. [Figure 3] FIG. 1 is a diagram showing an example of vibration characteristics of steam traps of multiple types and reference models. [Figure 4A] FIG. 10 is a diagram showing an example of a process for converting the vibration value of a type I first steam trap into the amount of steam leakage. [Figure 4B] FIG. 10 is a diagram showing an example of a process for converting the vibration value of a type VI first steam trap into the amount of steam leakage. [Figure 5] FIG. 1 is a diagram illustrating an example of vibration characteristics of several models of steam traps. [Figure 6] FIG. 10 is a diagram showing an example of a process for converting the vibration value of the second steam trap into the amount of steam leakage. [Figure 7] FIG. 10 is a diagram showing another example of a process for converting the vibration value of the reference steam trap into the amount of steam leakage. [Figure 8] FIG. 10 is a diagram showing another example of a process for converting the vibration value of a type I first steam trap into the amount of steam leakage. [Figure 9] FIG. 10 is a diagram showing another example of a process for converting the vibration value of the second steam trap into the amount of steam leakage. [Figure 10] 4 is a flowchart illustrating an example of operations and processes performed by a diagnostic device when diagnosing a target steam trap. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Elements with the same reference numerals in different drawings indicate the same or corresponding elements. Figure 1 is a block diagram showing the configuration of a diagnostic device 1 according to an embodiment of the present invention.

[0035] In a plant or the like equipped with a steam piping system, multiple steam traps are installed at appropriate locations in the piping system to discharge condensate (drain) generated within the piping system to the outside. The performance of the steam traps is diagnosed through periodic diagnosis, such as once a year. A periodic diagnosis worker carries diagnostic device 1 and moves around the plant, using diagnostic device 1 to diagnose the performance of each steam trap in turn. Note that the diagnosis of steam trap performance is not limited to periodic diagnosis, and can also be performed on an irregular basis. The following describes an example of a periodic diagnosis in which the amount of steam leakage from a steam trap is diagnosed.

[0036] If it is permitted to bring data processing devices such as laptop computers into the plant, the worker can carry the data processing device along with diagnostic device 1 and sequentially diagnose the steam leakage rate of each steam trap. In this case, diagnostic device 1 can transmit the diagnostic results of each steam trap in real time to a server device such as a cloud server via the data processing device and any communication network such as a public line network.

[0037] On the other hand, if it is prohibited to bring the data processing device into the plant, the worker stores the data processing device in a waiting area such as a company vehicle or a field office, and carries only diagnostic device 1 to sequentially diagnose the steam leakage rate of each steam trap. In this case, the diagnostic results for each steam trap are stored in diagnostic device 1. After the worker returns to the waiting area, diagnostic device 1 transmits the diagnostic results for the multiple steam traps stored in diagnostic device 1 to the server device via the data processing device and the communication network.

[0038] The following describes in detail the configuration of the diagnostic device 1. As shown in Fig. 1, the diagnostic device 1 includes a probe 19, a vibration sensor 11 (sensor), an amplifier circuit 12, a gain switching circuit 18 (setting unit), an operation unit 13, a display unit 14 (output unit), a memory unit 15 (output unit), a communication unit 16 (output unit), an IF (interface) unit 17 (output unit), and a control unit 10.

[0039] Probe 19 is a rod-shaped member whose tip is pressed against the steam trap, and vibrates at a predetermined resonant frequency. When the tip of probe 19 is pressed against the steam trap, vibration sensor 11 outputs an analog signal to amplifier circuit 12 that indicates the vibration of the steam trap transmitted to probe 19.

[0040] The amplifier circuit 12 is provided to improve the accuracy of conversion from an analog signal to a digital signal in the downstream AD converter 20. The amplifier circuit 12 amplifies the output signal of the vibration sensor 11. The amplifier circuit 12 includes a resistive element with a variable resistance value, and is configured to be able to adjust the gain when amplifying the output signal of the vibration sensor 11 by changing the resistance value of the resistive element.

[0041] The gain switching circuit 18 sets a gain when the amplifier circuit 12 amplifies the output signal of the vibration sensor 11. Specifically, the gain switching circuit 18 is configured by a switch circuit that switches the resistance values ​​of the resistor elements that make up the amplifier circuit 12. The gain switching circuit 18 switches the resistance values ​​of the resistor elements that make up the amplifier circuit 12 to a resistance value that corresponds to a gain instructed by a gain setting unit 80 (described later). In this way, the gain switching circuit 18 sets the gain instructed by the gain setting unit 80 as the gain when the amplifier circuit 12 amplifies the output signal of the vibration sensor 11.

[0042] The operation unit 13 is configured with operation switches and the like that allow the operator to input various pieces of information. The display unit 14 is configured using a liquid crystal display, an organic EL display, or the like. However, the operation unit 13 and the display unit 14 may be configured as one unit by using a touch panel display. The display unit 14 displays various pieces of information under the control of the control unit 10. For example, the display unit 14 displays (outputs) the amount of steam leakage from the steam trap converted by the conversion unit 60.

[0043] Storage unit 15 is configured using a rewritable semiconductor memory such as a flash memory. Various information is stored in storage unit 15 by control unit 10. FIG. 2 is a diagram showing an example of a management ledger 91. For example, as shown in FIG. 2, storage unit 15 stores management ledger 91 for managing multiple steam traps to be diagnosed.

[0044] Management ledger 91 is created in the data processing device. Specifically, management ledger 91 includes absolute position information I1, identification information I2, attribute information I3, and characteristic information I4 for each of the multiple steam traps to be diagnosed.

[0045] The absolute position information I1 is information that indicates the installation position of each steam trap. The management ledger 91 in Figure 2 shows an example in which the absolute position information I1 is written as coordinates that indicate the area in which each steam trap is installed when the plant is divided into multiple areas.

[0046] The identification information I2 is information for identifying each steam trap. Figure 2 shows an example in which trap numbers T1 to T9 for identifying each steam trap are written as the identification information I2.

[0047] Attribute information I3 is information that indicates the attributes of each steam trap. Figure 2 shows an example of attribute information I3 in which the manufacturer name, model, type, and model of each steam trap are described. The model is information that identifies the steam trap model (e.g., AB111).

[0048] The steam traps that can be installed in a plant are classified into several types depending on the valve opening and closing method. The type contains information (e.g., I) that specifies the valve opening and closing method of the steam trap.

[0049] Each type of steam trap is further classified into several models based on the maximum condensate discharge rate. Each model contains information (e.g., M11) that specifies the maximum condensate discharge rate for the steam trap.

[0050] The attribute information I3 may also include information indicating other attributes of the steam trap.

[0051] The characteristic information I4 is information about the various characteristics of each steam trap that is used to diagnose the performance of each steam trap. Figure 2 shows an example of characteristic information I4 that describes vibration characteristic information, type correction coefficients, and model correction coefficients that are used to diagnose the steam leakage rate of each steam trap.

[0052] Vibration characteristic information indicates the vibration characteristics of steam traps classified into each type and standard model. One standard model is defined for each type of steam trap. In the following explanation, models M11, M21, M31, M41, M51, and M61 are defined as standard models for steam traps of types I, II, III, IV, V, and VI. Vibration characteristics indicate the relationship between the amount of steam leakage in the steam trap and vibration values. The vibration characteristics of steam traps vary depending on the type and model.

[0053] For example, Fig. 2 shows an example in which information indicating the vibration characteristic G41 of a steam trap, a reference model M41 classified as Type IV, is described as vibration characteristic information corresponding to the steam trap. Fig. 2 also shows an example in which information indicating the vibration characteristic G11 of a steam trap, a type I and reference model M11, is described as vibration characteristic information corresponding to two steam traps, a reference model M11 and a model M12 classified as Type I. Details of the vibration characteristic information will be described later.

[0054] The type correction coefficient is used to determine the gain when amplifier circuit 12 amplifies the output signal of vibration sensor 11. The type correction coefficient is set based on the vibration characteristics of each steam trap and the vibration characteristics of a standard type steam trap. A standard type steam trap is a type steam trap that exhibits average vibration characteristics among multiple types I to VI of steam traps. In this embodiment, the standard type is assumed to be type IV.

[0055] For example, Figure 2 shows an example in which the type correction factor used when diagnosing a Type I steam trap is set to "C1." Similarly, Figure 2 shows an example in which the type correction factors used when diagnosing Type II, III, V, and VI steam traps are set to "C2," "C3," "1 / C5," and "1 / C6." Figure 2 also shows an example in which the type correction factor used when diagnosing a Type IV steam trap is set to "1." Details of the type correction factors will be described later.

[0056] The model correction coefficient is a set value used in the amplifier section 40 and the converter section 60 described below when diagnosing a steam trap of a type different from the standard type IV and a model different from the standard model.

[0057] For example, Figure 2 shows an example in which the model correction coefficient used when diagnosing a steam trap of type I, which is different from the reference type IV, and model M12, which is different from the reference model M11, is set to "C120." Figure 2 also shows an example in which the model correction coefficient used when diagnosing a steam trap of type V, which is different from the reference type IV, and model M52, which is different from the reference model M51, is set to "C520." Details of the model correction coefficient will be described later.

[0058] Hereinafter, the steam trap of the reference type IV and reference model M41 will be referred to as the reference steam trap (first steam trap). Steam traps of types and reference models different from the reference type IV will be referred to as the first steam trap. Steam traps of types and models different from the reference type IV will be referred to as the second steam trap.

[0059] In the example shown in Figure 2, the steam trap with trap number T6 is the reference steam trap. The steam traps with trap numbers T1, T5, T3, and T2 are first steam traps. The steam traps with trap numbers T4, T7, T9, and T8 are second steam traps.

[0060] 2, the order of the steam traps is the order of their diagnosis. However, the order of the steam traps in management ledger 91 is not limited to this, and they may be arranged in descending or ascending order of trap numbers, for example.

[0061] The communication unit 16 is configured using a communication circuit compatible with any communication method such as Bluetooth (registered trademark). The communication unit 16 receives various information from an external device such as the data processing device by communicating with the external device. The communication unit 16 outputs the received information to the control unit 10. Furthermore, under the control of the control unit 10, the communication unit 16 transmits (outputs) various information to the external device by communicating with the external device such as the data processing device.

[0062] For example, if the data processing device is permitted to be brought into the plant, the communication unit 16 receives the management ledger 91 from the data processing device and outputs the management ledger 91 to the control unit 10. In this case, the control unit 10 stores the management ledger 91 input from the communication unit 16 in the memory unit 15. The control unit 10 also controls the communication unit 16 to send an instruction to the data processing device requesting that the management ledger 91, to which the diagnostic results of each steam trap have been added, be sent to the server device.

[0063] The IF unit 17 is configured with input / output terminals and the like to which a flash memory 7 such as an SD card or a USB memory is detachably connected. With the flash memory 7 connected to the IF unit 17, the IF unit 17 inputs and outputs information between the flash memory 7 and the control unit 10.

[0064] For example, if the data processing device is prohibited from being brought into the plant, the IF unit 17 reads out the management ledger 91 stored in the flash memory 7 and outputs the read management ledger 91 to the control unit 10. In this case, the control unit 10 stores the management ledger 91 input from the IF unit 17 in the storage unit 15. The control unit 10 also controls the IF unit 17 to output (write) the management ledger 91, to which the diagnostic results of each steam trap have been added, to the flash memory 7. In this case, the worker performing the periodic diagnosis returns to the waiting area and then connects the flash memory 7 to the data processing device. Then, the worker uses the data processing device to obtain the updated management ledger 91 from the flash memory 7 and transmits the obtained updated management ledger 91 to the server device.

[0065] The control unit 10 is composed of a microcomputer having a CPU (Central Processing Unit) (not shown) that executes predetermined arithmetic processing, a non-volatile memory (not shown) such as an EEPROM in which predetermined control programs are stored, a RAM (Random Access Memory) (not shown) for temporarily storing data, and peripheral circuits therefor.

[0066] The control unit 10 includes, as the peripheral circuit, an AD converter 20. The AD converter 20 converts the output signal of the amplifier circuit 12 into a digital signal at a predetermined sampling period.

[0067] Furthermore, the control unit 10 functions as a gain setting unit 80 (setting unit), an adjustment unit 30, an amplification unit 40, a conversion unit 60, and a correction unit 90 by executing a control program stored in the nonvolatile memory.

[0068] The gain setting unit 80 refers to the management ledger 91 stored in the memory unit 15 and acquires a model correction coefficient associated with the steam trap to be diagnosed. The gain setting unit 80 determines the product of the acquired model correction coefficient and a predetermined reference gain as the initial value of the gain used by the amplifier circuit 12 when amplifying the output signal of the vibration sensor 11. Details of the reference gain will be described later. The gain setting unit 80 instructs the gain switching circuit 18 to set the determined initial value of the gain as the gain used by the amplifier circuit 12.

[0069] When the adjustment unit 30 detects that the AD converter 20 is overflowing, it decreases or increases the gain used by the amplifier circuit 12 until it detects that the AD converter 20 is not overflowing, and when it detects that the AD converter 20 is not overflowing, it outputs the output signal of the AD converter 20 to the amplifier unit 40. Details of the adjustment unit 30 will be described later.

[0070] Amplifying unit 40 refers to management ledger 91 stored in memory unit 15, and when the object to be diagnosed is the reference steam trap or the first steam trap, sets the amplification factor to "1" and outputs the output signal of AD converter 20 to conversion unit 60 without amplification. On the other hand, when the object to be diagnosed is the second steam trap, amplifying unit 40 obtains a model correction coefficient corresponding to the steam trap to be diagnosed from management ledger 91. Amplifying unit 40 sets the model correction coefficient as the amplification factor and amplifies the output signal of AD converter 20 by the amplification factor.

[0071] For example, when diagnosing the reference steam trap with trap number T6 in management ledger 91 in Figure 2, gain setting unit 80 obtains from management ledger 91 a model correction coefficient of "1" corresponding to the reference steam trap. In this case, gain setting unit 80 determines the product of model correction coefficient "1" and the reference gain as the initial value of the gain used by amplifier circuit 12 when amplifying the output signal of vibration sensor 11. Gain setting unit 80 instructs gain switching circuit 18 to set this initial gain value as the gain used by amplifier circuit 12. Because the target of diagnosis is the reference steam trap, amplifier unit 40 outputs the output signal of AD converter 20 to conversion unit 60 without amplifying it.

[0072] 2, gain setting unit 80 obtains the model correction coefficient "C1" corresponding to the first steam trap from management ledger 91. In this case, gain setting unit 80 determines the product of model correction coefficient "C1" and the reference gain as the initial value of the gain used by amplifier circuit 12 when amplifying the output signal of vibration sensor 11, and instructs gain switching circuit 18 to set this initial value of gain as the gain used by amplifier circuit 12. Because the target of diagnosis is the reference steam trap, amplifier unit 40 outputs the output signal of AD converter 20 to conversion unit 60 without amplifying it.

[0073] When diagnosing the second steam trap with trap number T4 in the management ledger 91 of FIG. 2 , the gain setting unit 80 obtains a model correction coefficient "C1" corresponding to the second steam trap from the management ledger 91. In this case, the gain setting unit 80 determines the product of the model correction coefficient "C1" and the reference gain as the initial value of the gain used by the amplifier circuit 12 when amplifying the output signal of the vibration sensor 11, and instructs the gain switching circuit 18 to set this initial value of the gain as the gain used by the amplifier circuit 12. Since the second steam trap is the target of diagnosis, the amplifier unit 40 obtains a model correction coefficient "C120" corresponding to the second steam trap from the management ledger 91. In this case, the amplifier unit 40 sets the model correction coefficient "C120" as the amplification factor and amplifies the output signal of the AD converter 20 by this amplification factor "C120."

[0074] Conversion unit 60 refers to management ledger 91 stored in memory unit 15, and if the steam trap to be diagnosed is a reference steam trap, obtains vibration characteristic information corresponding to that reference steam trap from management ledger 91. In this case, conversion unit 60 converts the vibration value of that reference steam trap indicated by the output signal of AD converter 20 output without amplification by amplifier 40 into the steam leakage amount of that reference steam trap based on the vibration characteristics indicated by the vibration characteristic information.

[0075] When the steam trap to be diagnosed is the first steam trap, conversion unit 60 acquires vibration characteristic information corresponding to that first steam trap from management ledger 91. In this case, conversion unit 60 converts the vibration value of that first steam trap indicated by the output signal of AD converter 20 output without amplification by amplifier 40 into the steam leakage amount of that first steam trap based on the vibration characteristic indicated by the vibration characteristic information.

[0076] When the steam trap to be diagnosed is the second steam trap, conversion unit 60 acquires vibration characteristic information and a model correction coefficient corresponding to the second steam trap from management ledger 91. Based on the vibration characteristics indicated by the vibration characteristic information and the model correction coefficient, conversion unit 60 converts the vibration value of the second steam trap indicated by the output signal of amplifier 40 into the amount of steam leakage from the second steam trap. Details of conversion unit 60 will be described later.

[0077] The correction unit 90 detects whether the conversion unit 60 is overflowing, and if it detects that the conversion unit 60 is overflowing, it decreases or increases the gain used by the amplifier circuit 12 until it detects that the conversion unit 60 is not overflowing.

[0078] Specifically, the correction unit 90 detects that the conversion unit 60 is overflowing when the conversion unit 60 converts, for a predetermined number of consecutive times, the vibration value indicated by the input signal to the conversion unit 60 into a steam leakage amount that is equal to or greater than the upper limit amount that can be converted by the conversion unit 60. The correction unit 90 also detects that the conversion unit 60 is overflowing when the conversion unit 60 converts, for a predetermined number of consecutive times, the vibration value indicated by the input signal to the conversion unit 60 into a steam leakage amount that is equal to or less than the lower limit amount that can be converted by the conversion unit 60.

[0079] If the correction unit 90 reduces the gain used by the amplifier circuit 12 until it detects that the conversion unit 60 is not overflowing, it further increases the amplification factor used by the amplifier circuit 40 to the maximum extent possible without causing the conversion unit 60 to overflow. On the other hand, if the correction unit 90 increases the gain used by the amplifier circuit 12 until it detects that the conversion unit 60 is not overflowing, it further decreases the amplification factor used by the amplifier circuit 40 to the maximum extent possible without causing the conversion unit 60 to overflow. Details of the correction unit 90 will be described later.

[0080] The vibration characteristic information, the reference gain, the type correction coefficient and the model correction coefficient set in the management ledger 91 (FIG. 2), and the conversion unit 60 will be described in detail below.

[0081] Fig. 3 is a diagram showing an example of vibration characteristics of steam traps of multiple types and reference models, in which the horizontal axis represents the amount of steam leakage from the steam trap and the vertical axis represents the vibration value (vibration level) of the steam trap.

[0082] Vibration characteristic G41 is the vibration characteristic of the reference steam trap classified as reference type IV and reference model M41 (Figure 2). Vibration characteristic G11 is the vibration characteristic of the first steam trap classified as type I and reference model M11 (Figure 2). Hereinafter, the first steam trap classified as type I and reference model M11 (Figure 2) will be abbreviated as the type I first steam trap. The same abbreviation will be used for the other first steam traps. Vibration characteristics G21, G31, G51, and G61 are the vibration characteristics (second vibration characteristics) of first steam traps of types II, III, V, and VI.

[0083] Furthermore, hereinafter, the six vibration characteristics G11, G21, G31, G41, G51, and G61 will be abbreviated as vibration characteristics G11 to G61. The vibration characteristics G11 to G61 are derived based on experimental values ​​using steam traps of each type and reference model.

[0084] The vibration value "L40" is the vibration value when the vibration of the standard steam trap and the first steam traps of types V and VI becomes saturated. When the vibration of a steam trap becomes saturated, this means that due to the structure of the steam trap, the amplitude of the steam trap's vibration reaches its maximum and it can no longer vibrate at a larger amplitude. The vibration values ​​"L10," "L20," and "L30" are the vibration values ​​when the vibration of the first steam traps of types I, II, and III becomes saturated.

[0085] As shown by the vibration characteristics G11 to G61, the vibration characteristics of the reference steam trap and the first steam trap have a characteristic in which the vibration value increases quadratically or exponentially as the amount of steam leakage increases.

[0086] In management ledger 91 (Fig. 2), the vibration characteristic information corresponding to each type IV steam trap contains a quadratic or exponential function that indicates the vibration characteristic G41. In management ledger 91 (Fig. 2), the vibration characteristic information corresponding to each type II, III, V, and VI steam trap contains a quadratic or exponential function that indicates the vibration characteristics G21, G31, G51, and G61 of the first steam traps that are the same model as each steam trap.

[0087] The reference gain is determined in advance based on the vibration characteristic G41 of the reference steam trap. Specifically, the reference gain is determined so that, when diagnosing the reference steam trap, the range of vibration values ​​of the reference steam trap indicated by the output signal of AD converter 20 (FIG. 1) matches the range of vibration values ​​("0" to "L40") indicated by vibration characteristic G41. In other words, the reference gain is set so that, when diagnosing the reference steam trap, amplifier 40 does not amplify the output signal of AD converter 20 (FIG. 1).

[0088] Therefore, when diagnosing the reference steam trap, the reference gain is set as the initial value of the gain used by amplifier circuit 12. Therefore, in management ledger 91 (FIG. 2), the type correction coefficient corresponding to the reference steam trap is entered as the ratio of the gain used by amplifier circuit 12 (reference gain) to the reference gain, which is "1."

[0089] As a result, when diagnosing the reference steam trap, gain setting unit 80 obtains from management ledger 91 (FIG. 2) a model correction coefficient "1" corresponding to the reference steam trap (a reference type IV steam trap), and determines the reference gain, which is the product of the obtained model correction coefficient "1" and the reference gain, as the initial value of the gain to be used by amplifier circuit 12. Gain setting unit 80 instructs gain switching circuit 18 to set the determined initial value of the gain as the gain to be used by amplifier circuit 12.

[0090] When diagnosing a reference steam trap, conversion unit 60 acquires vibration characteristic information corresponding to the reference steam trap from management ledger 91 (FIG. 2) stored in memory unit 15. When diagnosing a reference steam trap, amplifier unit 40 outputs the output signal of AD converter 20 to conversion unit 60 without amplifying it. Therefore, conversion unit 60 substitutes the vibration value (e.g., L1) of the reference steam trap indicated by the output signal of AD converter 20 into a quadratic function or exponential function indicating the vibration characteristic G41 indicated by the vibration characteristic information, and converts it into a steam leakage amount (e.g., B1) corresponding to the vibration value.

[0091] On the other hand, when diagnosing the Type I first steam trap, the initial value of the gain used by amplifier circuit 12 is set to the reference gain, just as when diagnosing the reference steam trap. In this case, because the target of diagnosis is the first steam trap, amplifier unit 40 outputs the output signal of AD converter 20 to conversion unit 60 without amplifying it. For this reason, even though signals indicating vibration values ​​in the range from "0" to "L40" can be input to conversion unit 60, only signals indicating vibration values ​​in the range from "0" to "L10" indicated by the vibration characteristic G11 of the Type I first steam trap are input.

[0092] For example, let us assume that the vibration value "L40" is 400 dB and the vibration value "L10" is 40 dB. Also, let us assume that the conversion unit 60 is capable of converting 400 different vibration values ​​into 400 different steam leakage amounts due to the performance of the CPU.

[0093] In this case, when diagnosing the reference steam trap, the range of vibration values ​​indicated by the signal input to conversion unit 60 is from 0 dB to 400 dB, so conversion unit 60 can convert 400 different vibration values ​​into 400 different steam leakage rates in 1 dB increments. In contrast, when diagnosing the Type I first steam trap, the range of vibration values ​​indicated by the signal input to conversion unit 60 is narrowed to a range of 0 dB to 40 dB. Therefore, conversion unit 60 can only convert 40 different vibration values ​​into 40 different steam leakage rates in 1 dB increments.

[0094] In this way, if amplifier circuit 12 amplifies the output signal of vibration sensor 11 by the reference gain, and conversion unit 60 converts the vibration value of Type I first steam trap indicated by the output signal of AD converter 20 into the amount of steam leakage without amplifying the output signal of AD converter 20, the accuracy of the conversion in conversion unit 60 will be worse than when diagnosing the reference steam trap. For this reason, the initial value of the gain used by amplifier circuit 12 when diagnosing the first steam trap is set so that the accuracy of the conversion in conversion unit 60 is the same as when diagnosing the reference steam trap.

[0095] Specifically, when diagnosing a Type I first steam trap, the initial value of the gain used by amplifier circuit 12 is set to the product of the reference gain and the ratio "C1 (=L40 / L10)" of the vibration value "L40" when the vibration of the reference steam trap saturates to the vibration value "L10" when the vibration of the first steam trap saturates. Therefore, in management ledger 91 (FIG. 2), the ratio "C1," which is a multiplier for the reference gain, is entered in the type correction coefficient corresponding to the Type I first steam trap.

[0096] As a result, when diagnosing the type I first steam trap, gain setting unit 80 obtains the type correction coefficient "C1" corresponding to the type I steam trap from management ledger 91 (FIG. 2), and determines the product of the obtained type correction coefficient "C1" and the reference gain as the initial value of the gain to be used by amplifier circuit 12. Gain setting unit 80 instructs gain switching circuit 18 to set the determined initial value of the gain as the gain to be used by amplifier circuit 12.

[0097] FIG. 4A illustrates an example of a process for converting the vibration value of a Type I first steam trap into a steam leakage rate. To diagnose the Type I first steam trap, the product of the type correction coefficient "C1" obtained from the management ledger 91 (FIG. 2) and the reference gain is set as the initial gain value used by the amplifier circuit 12. In this case, the signal amplified by the amplifier circuit 12 is converted into a digital signal by the AD converter 20 and then output to the converter 60 without being amplified by the amplifier 40. As a result, as shown in FIG. 4A, the maximum vibration value indicated by the output signal of the AD converter 20 input to the converter 60 is the vibration value "L10" when the vibration of the Type I first steam trap is saturated. In other words, when diagnosing the first steam trap, the converter 60 can convert the vibration value indicated by the output signal of the AD converter 20 into a steam leakage rate in units of "1 / C1," which is the same as when diagnosing the reference steam trap.

[0098] In the above example, conversion unit 60 can convert 400 different vibration values ​​indicated by the output signal of AD converter 20 into 400 different steam leakage rates in units of 0.1 (=1 / C1=L10 / L40=40 / 400) dB. This ensures that the accuracy of conversion by conversion unit 60 when diagnosing the Type I first steam trap is the same as when diagnosing the reference steam trap.

[0099] When diagnosing a Type I first steam trap, conversion unit 60 acquires vibration characteristic information corresponding to the first steam trap from management ledger 91 (FIG. 2) stored in memory unit 15. Conversion unit 60 substitutes the vibration value (e.g., L2) of the first steam trap indicated by the output signal of AD converter 20 into a quadratic function or exponential function indicating the vibration characteristic G11 indicated by the vibration characteristic information, and converts it into a steam leakage amount (e.g., B2) corresponding to the vibration value.

[0100] Similarly, when diagnosing a Type II first steam trap, the initial value of the gain used by amplifier circuit 12 is set to the product of the reference gain and the ratio "C2 (=L40 / L20)" of the vibration value "L20" (FIG. 3) when the vibration of the first steam trap saturates to the vibration value "L40" (FIG. 3) when the vibration of the reference steam trap saturates. Therefore, in management ledger 91 (FIG. 2), the ratio "C2," which is a multiplier for the reference gain, is entered in the type correction coefficient corresponding to the Type II first steam trap.

[0101] When diagnosing a Type III first steam trap, the initial value of the gain used by amplifier circuit 12 is set to the product of the reference gain and the ratio "C3 (=L40 / L30)" of the vibration value "L30" (FIG. 3) when the vibration of the first steam trap saturates to the vibration value "L40" (FIG. 3) of the reference steam trap. Therefore, in management ledger 91 (FIG. 2), the ratio "C3," which is a multiplier for the reference gain, is entered in the type correction coefficient corresponding to the Type III first steam trap.

[0102] Next, a case where a Type VI first steam trap is diagnosed will be described. In this case, as in the above, the initial value of the gain used by the amplifier circuit 12 is set to the reference gain. In this case, since the target of diagnosis is the first steam trap, the amplifier unit 40 outputs the output signal of the AD converter 20 to the conversion unit 60 without amplifying it. As a result, a signal indicating a vibration value ranging from "0" to "L40" is input to the conversion unit 60. However, although the conversion unit 60 is capable of outputting a signal indicating a steam leakage amount ranging from "0" to "B40," it will only output a signal indicating a steam leakage amount ranging from "0" to "B60" indicated by the Type VI vibration characteristic G61.

[0103] For ease of explanation, it is assumed that the vibration value "L40" is 400 dB, the steam leakage amount "B40" is 400 tons / year, and the steam leakage amount "B60" is 200 tons / year. Also, it is assumed that the conversion unit 60 is capable of converting 400 types of vibration values ​​into 400 types of steam leakage amounts due to the performance of the CPU, as described above.

[0104] In this case, when diagnosing the reference steam trap, the range of steam leakage rates indicated by the signal output from conversion unit 60 is from 0 tons / year to 400 tons / year. In contrast, when diagnosing a Type VI steam trap, the range of steam leakage rates indicated by the signal output from conversion unit 60 is narrowed to a range of 0 tons / year to 200 tons / year. As a result, conversion unit 60 can only convert 400 vibration values ​​into 200 steam leakage rates in units of 1 ton / year.

[0105] In this way, when the steam leakage rate (second leakage rate) when vibration saturates in the first steam trap (for example, "B60") is smaller than the steam leakage rate (first leakage rate) "B40" when vibration saturates in the reference steam trap, if the initial value of the gain used by amplifier circuit 12 is set to the reference gain, the accuracy of the conversion in conversion unit 60 will be worse than when diagnosing the reference steam trap. Therefore, even when diagnosing a type of first steam trap whose steam leakage rate when vibration saturates is smaller than the steam leakage rate of the reference steam trap when vibration saturates, the initial value of the gain used by amplifier circuit 12 is set so that the accuracy of the conversion in conversion unit 60 is the same as when diagnosing the reference steam trap.

[0106] Specifically, the steam leakage rate "B60" (second leakage rate) when the Type VI first steam trap is vibrating at saturation is smaller than the steam leakage rate "B40" (first leakage rate) when the reference steam trap is vibrating at saturation. Therefore, when diagnosing the Type VI first steam trap, the initial gain used by amplifier circuit 12 is set to the product of the reference gain and the reciprocal "1 / C6 (=B60 / B40)" of the ratio "C6 (=B40 / B60)" of the steam leakage rate "B40" when the reference steam trap is vibrating at saturation to the steam leakage rate "B60" when the Type VI steam trap is vibrating at saturation. Therefore, the type correction coefficient corresponding to the Type VI steam trap in management ledger 91 (FIG. 2) is entered as the reciprocal "1 / C6" of the ratio "C6," which is a multiplier for the reference gain.

[0107] As a result, when diagnosing a type VI first steam trap, gain setting unit 80 obtains from management ledger 91 the type correction coefficient "1 / C6" corresponding to the type VI first steam trap, and determines the product of this type correction coefficient "1 / C6" and the reference gain as the initial value of the gain to be used by amplifier circuit 12. Gain setting unit 80 instructs gain switching circuit 18 to set the determined initial value of the gain as the gain to be used by amplifier circuit 12.

[0108] FIG. 4B illustrates an example of a process for converting vibration values ​​of a Type VI first steam trap into steam leakage rates. Assume that the initial gain used by amplifier circuit 12 to diagnose a Type VI first steam trap is set to the product of the type correction coefficient "1 / C6" and the reference gain. In this case, the signal amplified by amplifier circuit 12 is converted into a digital signal by AD converter 20 and then output to converter 60 without being amplified by amplifier unit 40. As a result, as shown in FIG. 4B, the maximum steam leakage rate indicated by the output signal of converter 60 is "B60," the steam leakage rate at which the vibration of the Type VI first steam trap saturates. In other words, when diagnosing a Type VI first steam trap, converter 60 can convert the 400 vibration values ​​indicated by the output signal of AD converter 20 into 400 steam leakage rates in units of "1 / C6" times the value used when diagnosing a reference Type IV steam trap.

[0109] In the above example, conversion unit 60 can convert the 400 vibration values ​​indicated by the output signal of AD converter 20 into 400 steam leakage rates in units of 0.5 (=1 / C6=B60 / B40=200 / 400) tons / year. This allows the accuracy of conversion by conversion unit 60 when diagnosing the Type VI No. 1 steam trap to be the same as when diagnosing the reference steam trap.

[0110] When diagnosing a type VI first steam trap, conversion unit 60 refers to management ledger 91 (FIG. 2) stored in memory unit 15 and acquires vibration characteristic information associated with the type VI first steam trap to be diagnosed. Conversion unit 60 substitutes the vibration value (e.g., L3) of the type VI first steam trap indicated by the output signal of AD converter 20 into a quadratic function or exponential function indicating vibration characteristic G61 indicated by the vibration characteristic information, and converts it into a steam leakage amount (e.g., B3) corresponding to the vibration value.

[0111] As with the type VI first steam trap, the steam leakage rate when vibration of the type V first steam trap is saturated is smaller than the steam leakage rate "B40" when vibration of the reference steam trap is saturated, as shown in Figure 3. Therefore, when diagnosing the type V first steam trap, just as when diagnosing the reference steam trap, the initial value of the gain used by amplifier circuit 12 is set to the product of the reference gain and the reciprocal "1 / C5" of the ratio "C5" of the steam leakage rate "B40" when vibration of the reference steam trap is saturated to the steam leakage rate when vibration of the type V first steam trap is saturated.

[0112] Incidentally, when diagnosing a type II, III, or V first steam trap, conversion unit 60 also acquires vibration characteristic information associated with the first steam trap to be diagnosed from management ledger 91 (FIG. 2) stored in memory unit 15. Conversion unit 60 then substitutes the vibration value of the first steam trap to be diagnosed, indicated by the output signal of AD converter 20, into a quadratic function or exponential function that indicates the vibration characteristic indicated by the vibration characteristic information, and converts it into the steam leakage amount corresponding to the vibration value.

[0113] When diagnosing the second steam trap, the initial value of the gain used by amplifier circuit 12 is set to the product of the model correction coefficient associated with the second steam trap to be diagnosed in management ledger 91 (FIG. 2) and the reference gain, just as when diagnosing a first steam trap of the same model as the second steam trap. The amplification factor used by amplifier 40 is set so that the maximum vibration value of the second steam trap indicated by the output signal of amplifier 40 is the vibration value when the vibration of the second steam trap is saturated. This ensures that the accuracy of conversion by converter 60 when diagnosing the second steam trap is the same as when diagnosing the reference steam trap. The amplification factor when diagnosing the second steam trap will be specifically described below.

[0114] Figure 5 is a diagram showing an example of vibration characteristics of steam traps of multiple models. In Figure 5, vibration characteristic G51 is the vibration characteristic of the first steam trap of type V and reference model M51. Vibration characteristic G52 is the vibration characteristic of the second steam trap of type V and model M52. Vibration characteristic G53 is the vibration characteristic of the second steam trap of type V and model M53. Model M52 has a maximum condensate discharge rate greater than that of reference model M51 and less than that of model M53.

[0115] 5, when the amount of steam leakage is the same, the vibration value of vibration characteristic G52 is smaller than the vibration value of vibration characteristic G51 and larger than the vibration value of vibration characteristic G53. In other words, when the amount of steam leakage is the same, the model with a larger maximum condensate discharge amount has a smaller vibration value.

[0116] In Figure 5, ratio C520 is the ratio (=L510 / L520) of the vibration value "L510" of vibration characteristic G51 to the vibration value "L520" of vibration characteristic G52 when the steam leakage rate is "B50". Note that steam leakage rate "B50" is the steam leakage rate when vibration is saturated in the Type V first steam trap. Ratio C522 is the ratio (=L512 / L522) of the vibration value "L512" of vibration characteristic G51 to the vibration value "L522" of vibration characteristic G52 when the steam leakage rate is "B52".

[0117] The ratio C520 and the ratio C522 both had a value of X and were consistent. "Consistent" refers to consistency within a predetermined error range, and this also applies to the following explanations. Thus, the ratio of the vibration value of the vibration characteristic G51 to the vibration value of the vibration characteristic G52 was constant regardless of the amount of steam leakage.

[0118] 5, ratio C530 is the ratio (=L510 / L530) of the vibration value "L510" of vibration characteristic G51 to the vibration value "L530" of vibration characteristic G53 when the amount of steam leakage is "B50". Ratio C532 is the ratio (=L512 / L532) of the vibration value "L512" of vibration characteristic G51 to the vibration value "L532" of vibration characteristic G53 when the amount of steam leakage is "B52".

[0119] The ratio C530 and the ratio C532 both had a value of Y and were consistent. Thus, the ratio of the vibration value of the vibration characteristic G51 to the vibration value of the vibration characteristic G53 was also constant regardless of the amount of steam leakage.

[0120] Similarly, the same results as above were obtained from the vibration characteristics of the first steam traps of types I to IV and VI and the second steam traps of each model different from the reference models of types I to IV and VI. In other words, the ratio of the vibration value of the vibration characteristic of the first steam trap of the same model as the second steam trap to the vibration value of the vibration characteristic of the second steam trap was constant regardless of the amount of steam leakage.

[0121] For example, when diagnosing a second steam trap of type V, model M52 (FIG. 2), the amplification factor used by amplifier 40 is set to "1," just as when diagnosing a first steam trap of type V. In this case, the maximum vibration value of the steam trap indicated by the output signal of amplifier 40 is "L510," the vibration value when the vibration of the first steam trap is saturated, which is greater than "L520," the vibration value when the vibration of the second steam trap is saturated. Therefore, the accuracy of conversion by converter 60 when diagnosing the second steam trap is worse than when diagnosing the first steam trap.

[0122] Therefore, when diagnosing the second steam trap, the amplification factor is set so that the maximum value of the steam trap vibration indicated by the output signal of the amplifier unit 40 becomes the vibration value "L520", which is smaller than the vibration value "L510".

[0123] Specifically, when diagnosing a second steam trap, the amplification factor is set to the ratio (for example, C520 (= L510 / L520)) of the vibration value of the vibration characteristic (first vibration characteristic) of the second steam trap to the vibration value of the vibration characteristic (second vibration characteristic) of a first steam trap of the same model as the second steam trap.

[0124] Therefore, in the management ledger 91 (Figure 2), the model correction coefficient corresponding to the second steam trap is recorded as the ratio of the vibration value of the vibration characteristics of the second steam trap to the vibration value of the vibration characteristics of the first steam trap of the same model as the second steam trap (for example, C520 (= L510 / L520)).

[0125] FIG. 6 shows an example of a process for converting the vibration value of a second steam trap into a steam leakage amount. For example, suppose a second steam trap classified as Type I and Model M12, which is described in management ledger 91 shown in FIG. 2, is to be diagnosed. In this case, amplifier 40 obtains a model correction coefficient "C120" corresponding to the second steam trap from management ledger 91 (FIG. 2) and sets the model correction coefficient "C120" as the amplification factor. In this case, the maximum vibration value indicated by the output signal of amplifier 40 and input to conversion unit 60 is the vibration value "L12" when the vibration of the second steam trap is saturated, as shown in FIG. 6.

[0126] In this case, conversion unit 60 acquires vibration characteristic information and a model correction coefficient corresponding to the second steam trap from management ledger 91 (FIG. 2). The vibration characteristic information indicates the vibration characteristic G11 (FIG. 5) (second vibration characteristic) of a first steam trap of the same type I as the second steam trap. The model correction coefficient is set to the ratio of the vibration value of the vibration characteristic of the first steam trap to the vibration value of the vibration characteristic of the second steam trap (for example, C520 (= L510 / L520)).

[0127] Therefore, the conversion unit 60 calculates the product of a quadratic function or exponential function indicating the vibration characteristic G11 (Figure 5) of the first steam trap indicated by the vibration characteristic information and the ratio of the vibration value of the vibration characteristic of the second steam trap to the vibration value of the vibration characteristic G11 (Figure 5) of the first steam trap, which is the inverse of the model correction coefficient, as a function indicating the vibration characteristic G12 of the second steam trap.

[0128] Then, the conversion unit 60 substitutes the vibration value (e.g., L4) of the second steam trap indicated by the output signal of the amplification unit 40 into a function indicating the vibration characteristic G12, and converts it into the steam leakage amount (e.g., B4) corresponding to the vibration value.

[0129] Furthermore, the vibration characteristic information stored in the management ledger 91 is not limited to information indicating a quadratic function or exponential function that represents the vibration characteristic of each steam trap, but may also be information indicating a function that linearly approximates the vibration characteristic of each steam trap.

[0130] Fig. 7 is a diagram showing another example of the process of converting the vibration value of the reference steam trap into a steam leakage amount. In addition to the above, when diagnosing the reference steam trap, conversion unit 60 may substitute the vibration value (e.g., L1) of the reference steam trap indicated by the output signal of AD converter 20 into function G411, which is a linear approximation of vibration characteristic G41 indicated by the vibration characteristic information, as shown in Fig. 7, to convert the vibration value into a steam leakage amount (e.g., B411) corresponding to the vibration value.

[0131] Figure 8 is a diagram showing another example of the process of converting the vibration value of the type I first steam trap into a steam leakage amount. Similarly, when diagnosing the type I first steam trap, conversion unit 60 may substitute the vibration value (e.g., L2) of the type I first steam trap indicated by the output signal of AD converter 20 into function G111, which is a linear approximation of vibration characteristic G11 indicated by the vibration characteristic information, as shown in Figure 8, to convert the vibration value into a steam leakage amount (e.g., B112) corresponding to the vibration value.

[0132] Similarly, when diagnosing first steam traps of types II, III, V, and VI, the conversion unit 60 may substitute the vibration value of the first steam trap of types II, III, V, and VI indicated by the output signal of the AD converter 20 into a function that linearly approximates the vibration characteristics G21, G31, G51, and G61 indicated by the vibration characteristic information, and convert the vibration value into the amount of steam leakage corresponding to the vibration value.

[0133] 9 shows another example of a process for converting the vibration value of the second steam trap into a steam leakage amount. Similarly, when diagnosing a second steam trap of type I and model M12 (FIG. 2), the conversion unit 60 may convert the vibration value (e.g., L4) of the second steam trap indicated by the output signal of the amplifier 40 into a function G121 obtained by linearly approximating a vibration characteristic G12 (FIG. 6) obtained by multiplying a vibration characteristic G11 indicated by the vibration characteristic information by the reciprocal of a model correction coefficient, as shown in FIG. 9, to convert the vibration value into a steam leakage amount (e.g., B124) corresponding to the vibration value. Note that instead of function G121, the conversion unit 60 may use a function obtained by multiplying a function G111 (FIG. 8) obtained by linearly approximating a vibration characteristic G11 indicated by the vibration characteristic information by the reciprocal of a model correction coefficient.

[0134] Similarly, when diagnosing a second steam trap of another type and model, the conversion unit 60 may substitute the vibration value of the second steam trap indicated by the output signal of the amplifier unit 40 into a function obtained by linearly approximating the vibration characteristics obtained by multiplying the vibration characteristics indicated by the vibration characteristic information by the reciprocal of the model correction coefficient, or into a function obtained by multiplying the function obtained by linearly approximating the vibration characteristics indicated by the vibration characteristic information by the reciprocal of the model correction coefficient, to convert the vibration value into the steam leakage amount corresponding to the vibration value.

[0135] The procedure for periodic diagnosis using diagnostic device 1 will be described below. A periodic diagnosis worker carries diagnostic device 1 (and, if permitted, the data processing device) around the plant and uses diagnostic device 1 to sequentially diagnose the steam leakage rate of each steam trap. During this process, the worker operates operation unit 13, which causes control unit 10 to display management ledger 91 stored in memory unit 15 on display unit 14. This allows the worker to recognize the diagnosis order of multiple steam traps installed in the plant, as well as the absolute position information I1, identification information I2, and attribute information I3 of each steam trap. The worker moves to the location of the steam trap to be diagnosed this time, following the diagnosis order and absolute position that can be recognized from the displayed management ledger 91.

[0136] 10 is a flowchart showing an example of the operations and processes performed by diagnostic device 1 when diagnosing a target steam trap. When the operator moves to the installation location of the target steam trap to be diagnosed this time, he or she operates operation unit 13 to select one target steam trap to be diagnosed this time from among the multiple target steam traps included in management ledger 91 (step S11). As a result, information indicating that the one target steam trap has been selected as the target for diagnosis this time (hereinafter, selection information) is input from operation unit 13 to control unit 10.

[0137] When the selection information is input to the control unit 10, the gain setting unit 80 obtains the model correction coefficient corresponding to the target steam trap indicated by the selection information from the management ledger 91, and sets the product of the model correction coefficient and the reference gain as the initial value of the gain used by the amplifier circuit 12 (step S12).

[0138] Next, amplifier 40 refers to management ledger 91, and if the target steam trap is the reference steam trap or the first steam trap, sets the amplification factor to "1." If the target steam trap is the second steam trap, amplifier 40 obtains a model correction coefficient corresponding to the target steam trap from management ledger 91 and sets the model correction coefficient as the amplification factor (step S13).

[0139] Next, the operator presses probe 19 (FIG. 1) of diagnostic device 1 against the target steam trap to be diagnosed this time (step S14).

[0140] When probe 19 (FIG. 1) of diagnostic device 1 is pressed against the target steam trap, adjustment unit 30 detects whether AD converter 20 is overflowing or not (step S15).

[0141] Specifically, while probe 19 (FIG. 1) is pressed against the target steam trap, vibration sensor 11 outputs an analog signal indicating the vibration of the target steam trap. This analog signal is amplified by amplifier circuit 12 using the gain set in step S12 and input to AD converter 20. AD converter 20 converts the signal amplified by amplifier circuit 12 into a digital signal.

[0142] The adjustment unit 30 detects that the AD converter 20 is overflowing when the value indicated by the output signal of the AD converter 20 is equal to a predetermined upper limit value (e.g., 400) or is less than a predetermined lower limit value (e.g., 350) that is smaller than the upper limit value (YES in step S15). On the other hand, the adjustment unit 30 detects that the AD converter 20 is not overflowing when the value indicated by the output signal of the AD converter 20 is equal to or greater than the lower limit value (e.g., 350) and less than the upper limit value (e.g., 400) (NO in step S15). The upper limit value and the lower limit value can be determined based on the specifications of the AD converter 20. The upper limit value and the lower limit value are pre-stored in the storage unit 15 by an administrator of the diagnostic device 1 operating the operation unit 13.

[0143] If the adjustment unit 30 detects that the AD converter 20 is overflowing (YES in step S15), the adjustment unit 30 adjusts the gain used by the amplifier circuit 12 in step S16 (step S16).

[0144] Specifically, it is assumed that in step S15, the adjustment unit 30 detects that the AD converter 20 is overflowing because the value indicated by the output signal from the AD converter 20 is equal to a predetermined upper limit value (e.g., 400). In this case, in step S16, the adjustment unit 30 instructs the gain setting unit 80 to decrease the gain by a predetermined amount. In accordance with this instruction, the gain setting unit 80 instructs the gain switching circuit 18 to set the gain used by the amplifier circuit 12 to a gain that is decreased by the predetermined amount from the current gain.

[0145] On the other hand, suppose that in step S15, the adjustment unit 30 detects that the AD converter 20 is overflowing because the value indicated by the output signal from the AD converter 20 is less than a predetermined lower limit (e.g., 350). In this case, in step S16, the adjustment unit 30 instructs the gain setting unit 80 to increase the gain by a predetermined amount. In accordance with this instruction, the gain setting unit 80 instructs the gain switching circuit 18 to set the gain used by the amplifier circuit 12 to a gain that is increased by the predetermined amount from the current gain.

[0146] Note that the method by which the adjustment unit 30 increases or decreases the gain in step S16 is not limited to this. For example, the adjustment unit 30 may instruct the gain setting unit 80 to set the product of a predetermined decrease rate less than 1 and the current gain as the gain used by the amplifier circuit 12, thereby causing the gain switching circuit 18 to decrease the gain. Similarly, the adjustment unit 30 may instruct the gain setting unit 80 to set the product of a predetermined increase rate greater than 1 and the current gain as the gain used by the amplifier circuit 12, thereby causing the gain switching circuit 18 to increase the gain.

[0147] After step S16, the adjustment unit 30 executes step S15 again. That is, in steps S15 and S16, when the adjustment unit 30 detects that the AD converter 20 is overflowing, the adjustment unit 30 decreases or increases the gain until it detects that the AD converter 20 is not overflowing.

[0148] If the adjustment unit 30 detects in step S15 that the AD converter 20 is not overflowing (NO in step S15), it outputs the output signal of the AD converter 20 to the amplification unit 40. As a result, the amplification unit 40 amplifies the output signal of the AD converter 20 by the amplification factor set in step S13 (step S17), and the conversion unit 60 converts the vibration value indicated by the signal amplified by the amplification unit 40 into the amount of steam leakage (step S18).

[0149] Next, the correction unit 90 detects that the conversion unit 60 is overflowing if the conversion unit 60 converts the vibration value indicated by the input signal of the conversion unit 60 into a steam leakage amount greater than the upper limit amount that can be converted by the conversion unit 60 a predetermined number of times (for example, three times) in succession, and if the conversion unit 60 converts into a steam leakage amount less than the lower limit amount that can be converted by the conversion unit 60 (YES in step S19).

[0150] The upper limit of the steam leakage amount that can be converted in the conversion unit 60 is the steam leakage amount when the vibration indicated by the vibration characteristics of the target steam trap is saturated (e.g., B10 (Figure 3), B12 (Figure 6)). The lower limit of the steam leakage amount that can be converted in the conversion unit 60 is the lower limit of the steam leakage amount indicated by the vibration characteristics of the target steam trap (e.g., 0 (Figure 3, Figure 6)).

[0151] On the other hand, if the conversion unit 60 does not convert the vibration value indicated by the input signal to the conversion unit 60 into a steam leakage amount greater than the upper limit amount that can be converted in the conversion unit 60, or does not convert the vibration value indicated by the input signal to the conversion unit 60 into a steam leakage amount less than the lower limit amount that can be converted in the conversion unit 60, the correction unit 90 detects that the conversion unit 60 is not overflowing (NO in step S19).

[0152] If the corrector 90 detects in step S19 that the converter 60 has overflowed (YES in step S19), the corrector 90 adjusts the gain used by the amplifier circuit 12 (step S20).

[0153] Specifically, in step S19, the correction unit 90 detects that the conversion unit 60 is overflowing because the conversion unit 60 has converted the vibration value into a steam leakage amount equal to or greater than the upper limit a predetermined number of times in succession. In this case, in step S20, the correction unit 90 instructs the gain setting unit 80 to decrease the gain by a predetermined amount. In accordance with this instruction, the gain setting unit 80 instructs the gain switching circuit 18 to set the gain used by the amplifier circuit 12 to a gain that is decreased by the predetermined amount from the current gain.

[0154] On the other hand, in step S19, the correction unit 90 detects that the conversion unit 60 is overflowing because the conversion unit 60 has converted the vibration value into a steam leakage amount equal to or less than the lower limit value a predetermined number of times in succession. In this case, in step S20, the correction unit 90 instructs the gain setting unit 80 to increase the gain by a predetermined amount. In accordance with this instruction, the gain setting unit 80 instructs the gain switching circuit 18 to set the gain used by the amplifier circuit 12 to a gain that is increased by the predetermined amount from the current gain.

[0155] Note that the method by which the correction unit 90 increases or decreases the gain in step S20 is not limited to this. For example, the correction unit 90 may instruct the gain setting unit 80 to set the product of a predetermined decrease rate less than 1 and the current gain as the gain used by the amplifier circuit 12, thereby causing the gain switching circuit 18 to decrease the gain. Similarly, the correction unit 90 may instruct the gain setting unit 80 to set the product of a predetermined increase rate greater than 1 and the current gain as the gain used by the amplifier circuit 12, thereby causing the gain switching circuit 18 to increase the gain.

[0156] After step S20, the correction unit 90 executes step S19 again. That is, in steps S19 and S20, when the correction unit 90 detects that the conversion unit 60 has overflowed, the correction unit 90 decreases or increases the gain until it detects that the conversion unit 60 has not overflowed.

[0157] If the correction unit 90 detects in step S19 that the conversion unit 60 is not overflowing (NO in step S19), it adjusts the amplification factor used by the amplification unit 40 to increase or decrease it to the maximum extent possible within the range in which the conversion unit 60 does not overflow (step S21).

[0158] Specifically, it is assumed that the correction unit 90 increased the gain in step S20 immediately before step S21. In this case, in step S21, the correction unit 90 instructs the amplification unit 40 to decrease the gain by a predetermined amount, thereby decreasing the gain used by the amplification unit 40 by the predetermined amount, and then, as in step S19, repeats the process of detecting whether the conversion unit 60 has overflowed. Then, if the correction unit 90 detects that the conversion unit 60 has overflowed during this repetition, it sets the gain of the amplification unit 40 to the gain that was set immediately before the gain that was set at the time of the detection.

[0159] On the other hand, suppose that the correction unit 90 reduced the gain in step S20, which is immediately before step S21. In this case, in step S21, the correction unit 90 instructs the amplification unit 40 to increase the gain by a predetermined amount, thereby increasing the gain used by the amplification unit 40 by the predetermined amount, and then, as in step S19, repeats the process of detecting whether the conversion unit 60 has overflowed. Then, if the correction unit 90 detects that the conversion unit 60 has overflowed during this repetition, it sets the gain of the amplification unit 40 to the gain that was set immediately before the gain that was set at the time of the detection.

[0160] Note that the method by which the correction unit 90 increases and decreases the amplification factor in step S21 is not limited to this. For example, the correction unit 90 may decrease the amplification factor by instructing the amplification unit 40 to set the amplification factor to the product of a predetermined decrease rate smaller than 1 and the current amplification factor. Similarly, the correction unit 90 may increase the amplification factor by instructing the amplification unit 40 to set the amplification factor to the product of a predetermined increase rate larger than 1 and the current amplification factor.

[0161] Furthermore, if the correction unit 90 does not perform step S20 after step S18 and before performing step S21, the conversion unit 60 does not overflow, and therefore the amplification factor is not changed in step S21.

[0162] After step S21, conversion unit 60 converts the vibration value of the target steam trap into the steam leakage rate of the target steam trap, thereby calculating the steam leakage rate of the target steam trap (step S22). Control unit 10 outputs the steam leakage rate of the target steam trap calculated in step S22 (step S23), and ends the process related to the diagnosis of the target steam trap selected in step S21.

[0163] In step S23, control unit 10 outputs, for example, an instruction to display the steam leakage rate of the target steam trap calculated in step S22 to display unit 14. Display unit 14 displays (outputs) information indicating the steam leakage rate of the target steam trap in accordance with the display instruction.

[0164] Control unit 10 also adds information indicating the steam leakage rate of the target steam trap calculated in step S22 to a location corresponding to the target steam trap in management ledger 91. Control unit 10 stores (outputs) management ledger 91 after the addition in memory unit 15. As a result, control unit 10 updates management ledger 91 stored in memory unit 15.

[0165] When the operator does not carry the data processing device and has completed the diagnosis of all the target steam traps, the operator connects flash memory 7 to IF unit 17. Control unit 10 acquires management ledger 91 stored in memory unit 15 and outputs a storage instruction for management ledger 91 to IF unit 17. IF unit 17 stores (outputs) management ledger 91 in flash memory 7 in accordance with the storage instruction.

[0166] On the other hand, if the operator is carrying the data processing device and has completed the diagnosis of all target steam traps, the control unit 10 acquires the updated management ledger 91 stored in the memory unit 15 and sends an instruction to the data processing device via the communication unit 16 to transmit the updated management ledger 91 to the server device. In accordance with the instruction, the data processing device transmits (outputs) the updated management ledger 91 to the server device.

[0167] As described above, in this embodiment, if AD converter 20 is overflowing, the gain is decreased or increased until AD converter 20 no longer overflows. Therefore, the analog signal indicating the vibration of the target steam trap can be converted into an appropriate digital signal in AD converter 20. This allows each of a plurality of steam traps to be designated as a target steam trap to be diagnosed, and the output signal of AD converter 20 can be output as a signal indicating an appropriate vibration value of the target steam trap.

[0168] Furthermore, in this embodiment, if the conversion unit 60 is overflowing, the gain used by the amplifier circuit 12 is increased or decreased until the conversion unit 60 no longer overflows. This allows the conversion unit 60 to appropriately convert the vibration value of the target steam trap into the amount of steam leakage. Furthermore, in step S21 (FIG. 10), the amplification factor is increased or decreased to the maximum extent possible within the range in which the conversion unit 60 does not overflow. This allows the conversion unit 60 to convert the vibration value into the amount of steam leakage with as high an accuracy as possible while preventing the conversion unit 60 from overflowing.

[0169] Note that correction unit 90 may not adjust the amplification factor. Specifically, step S21 (FIG. 10) may be omitted. Also, control unit 10 may not function as correction unit 90. In this case, steps S19 to S22 may be omitted, and in step S23, control unit 10 may output the steam leakage amount of the target steam trap calculated in step S18. [Explanation of symbols]

[0170] 1: Diagnostic equipment 11: Vibration sensor (sensor) 12: Amplification circuit 14: Display unit (output unit) 15: Memory unit (output unit) 16: Communication unit (output unit) 17: IF section (output section) 18: Gain switching circuit (setting section) 20: AD converter 30: Adjustment section 40: Amplification section 60: Conversion section 80: Gain setting section (setting section) 90: Correction section

Claims

1. A diagnostic device for diagnosing a plurality of steam traps, comprising: a sensor that outputs an analog signal indicative of vibration of a target steam trap that is a target steam trap for diagnosis; an amplifier circuit for amplifying an output signal of the sensor; a setting unit that sets a gain when the amplifier circuit amplifies the output signal of the sensor; an AD converter that converts the output signal of the amplifier circuit into a digital signal; an adjustment unit that, when detecting that the AD converter has overflowed, causes the setting unit to decrease or increase the gain until it detects that the AD converter has not overflowed, and outputs an output signal of the AD converter when it detects that the AD converter has not overflowed; A diagnostic device comprising:

2. the adjustment unit detects that the AD converter is overflowing when the value indicated by the output signal of the AD converter is equal to a predetermined upper limit value or when the value indicated by the output signal of the AD converter is less than a predetermined lower limit value that is smaller than the upper limit value. The diagnostic device of claim 1 .

3. The plurality of steam traps are classified into a plurality of types of steam traps; Each type of steam trap is classified into a plurality of models of steam traps, including a first steam trap of a predetermined reference model and a second steam trap of a model different from the reference model; the setting unit sets, as the initial value of the gain, a product of a predetermined reference gain and a ratio of a vibration value when vibration saturates in the first steam trap of a predetermined reference model to a vibration value when vibration saturates in the first steam trap of the same model as the target steam trap. The diagnostic device according to claim 1 or 2.

4. an amplifier that amplifies the output signal of the AD converter using, as an amplification factor, a model correction coefficient that is the ratio of a vibration value of a second vibration characteristic that indicates the relationship between the amount of steam leakage and the vibration value of a first steam trap of the same model as the target steam trap to a vibration value of a first vibration characteristic that indicates the relationship between the amount of steam leakage and the vibration value of the target steam trap; a conversion unit that converts the vibration value of the target steam trap indicated by the output signal of the amplifier unit into the amount of steam leakage from the target steam trap; an output unit that outputs the amount of steam leakage from the target steam trap; The diagnostic device of claim 3 further comprising:

5. a correction unit that, when detecting that the conversion unit has overflowed, causes the setting unit to decrease or increase the gain until the conversion unit detects that the conversion unit has not overflowed; The diagnostic device of claim 4 further comprising:

6. The correction unit When the setting unit reduces the gain until it detects that the conversion unit is not overflowing, the setting unit further increases the amplification factor to the maximum extent within a range in which the conversion unit does not overflow, When the setting unit increases the gain until it detects that the conversion unit is not overflowing, the setting unit further decreases the amplification factor to the maximum extent within a range in which the conversion unit does not overflow. The diagnostic device according to claim 5.

7. The correction unit When the converter converts the vibration value indicated by the input signal of the converter into a steam leakage amount equal to or greater than the upper limit amount that can be converted by the converter a predetermined number of times in succession, and When the converter converts the vibration value indicated by the input signal of the converter into a steam leakage amount that is equal to or less than the lower limit amount that can be converted by the converter a predetermined number of times in succession, Detecting that the conversion unit is overflowing; The diagnostic device according to claim 5.

8. The setting unit When a second leakage amount, which is the amount of steam leakage when vibration saturates in the first steam trap of the same model as the target steam trap, is smaller than a first leakage amount, which is the amount of steam leakage when vibration saturates in the first steam trap of the reference model, the product of the reciprocal of the ratio of the first leakage amount to the second leakage amount and the reference gain is set as the initial value of the gain. The diagnostic device of claim 3 .

9. When the target steam trap is the second steam trap, the conversion unit converts the vibration value of the target steam trap indicated by the output signal of the amplification unit into a steam leakage amount of the target steam trap based on the second vibration characteristic and the model correction coefficient. The diagnostic device of claim 4.

10. When the target steam trap is the second steam trap, the conversion unit converts the vibration value of the target steam trap indicated by the output signal of the amplification unit into a steam leakage amount of the target steam trap based on a linear approximation function of the second vibration characteristic and the model correction coefficient. The diagnostic device of claim 4.

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