JP7485442B1 - Diagnostic Equipment - Google Patents

Abstract

[Problem] A diagnostic device outputs a signal indicating an appropriate vibration value for each of a plurality of steam traps. [Solution] A diagnostic device includes a sensor that outputs an analog signal indicating the vibration of a target steam trap that is a steam trap to be diagnosed, an amplifier circuit that amplifies the 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, and an adjustment unit that, when it detects 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, when it detects that the AD converter has not overflowed, outputs the output signal of the AD converter. [Selected Figure] Figure 1

Description

The present invention relates to a technology for measuring the vibration of a steam trap.

In plants equipped with steam piping systems, condensate (drain) can occur within the piping system due to heat exchange or heat dissipation. Allowing this condensate to remain within the piping system can 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.

If the sealing performance of a steam trap is impaired due to deterioration over time 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, traditionally, the vibration of each of multiple steam traps is measured periodically, such as once a year, using a diagnostic device such as that disclosed in Patent Document 1, and each steam trap is diagnosed based on the vibration values of the measurement results and the vibration characteristics of each steam trap.

JP 2018-84418 A

However, when diagnosing multiple steam traps using one diagnostic device, depending on how the steam traps are used, the vibration of the steam trap 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, and is therefore unable to properly diagnose the steam traps.

The present invention was made in consideration of these circumstances, and aims to provide a diagnostic device that can output a signal indicating the appropriate vibration value for each of multiple steam traps.

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 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, 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.

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

However, according to this aspect, when the AD converter is overflowing, the gain is decreased or increased until the AD converter no longer overflows, so that the analog signal indicating the vibration of the target steam trap can be converted into an appropriate digital signal in the AD converter. As a result, this aspect can treat 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.

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.

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.

In the above aspect, the multiple steam traps are classified into multiple types of steam traps, and each type of steam trap is classified into multiple 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 the initial value of the gain to the product of a predetermined reference gain and a ratio of the vibration value when the vibration saturates in the first steam trap of a predetermined reference model to the vibration value when the vibration saturates in the first steam trap of the same model as the target steam trap.

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

Therefore, in a situation where the AD converter does not overflow, this embodiment can convert an analog signal indicating the vibration of the target steam trap 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.

In the above aspect, the device may further include an amplifier 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 in the 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 in 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.

The inventor 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 amount of steam leakage was the same. As a result, the inventor found that the ratio of the vibration values of the first steam trap of the same model as the target steam trap to the vibration values of the target steam trap was constant regardless of the amount of steam leakage.

In this embodiment, the initial value of the gain is set to the product of the ratio of the vibration value when the vibration of a first steam trap of a reference type is saturated to the vibration value when the vibration of a first steam trap of the same type as the target steam trap is saturated, and the reference gain. In addition, in the amplifier unit, the output signal of the AD converter is amplified 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 of the amplifier unit is then converted into the amount of steam leakage from the target steam trap.

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

In the above aspect, the device may further include a correction unit that, when it detects that the conversion unit has overflowed, causes the setting unit to decrease or increase the gain until it detects that the conversion unit has not overflowed.

Depending on the usage conditions of the target steam trap, the vibration value of the target steam trap indicated by the output signal of the amplifier unit may exceed the range of vibration that can be converted into the amount of steam leakage in the conversion unit, causing the conversion unit to overflow. However, in this embodiment, when the conversion unit is overflowing, the gain is increased or decreased until the conversion unit no longer overflows, so that the conversion unit can appropriately convert the vibration value of the target steam trap into the amount of steam leakage.

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

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

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 a predetermined number of consecutive times into a steam leakage amount equal to or greater than the upper limit amount that can be converted by the conversion unit, and when the conversion unit converts the vibration value indicated by the input signal of the conversion unit a predetermined number of consecutive times into a steam leakage amount equal to or less than the lower limit amount that can be converted by the conversion unit.

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 equal to or greater than the upper limit or equal to or less than the lower limit that can be converted by the conversion unit a predetermined number of times in succession, it is possible to properly detect that the conversion unit is overflowing.

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 product of the inverse of the ratio of the first leakage amount to the second leakage amount and the reference gain as the initial value of the gain.

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 gain value.

Therefore, in a situation where the AD converter does not overflow, this embodiment can convert an analog signal indicating the vibration value of the target steam trap 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.

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 amplifier unit into the amount of steam leakage from the target steam trap based on the second vibration characteristic and the model correction coefficient.

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 the product of the second vibration characteristic and 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 amount of steam leakage corresponding to that vibration value.

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 amplifier unit into the amount of steam leakage from the target steam trap based on a linear approximation function of the second vibration characteristic and the model correction coefficient.

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 amount of steam leakage 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 makes it possible to simplify the conversion unit.

The present invention makes it possible to provide a diagnostic device that can output a signal indicating the appropriate vibration value for each of multiple steam traps.

1 is a block diagram showing a configuration of a diagnostic device according to an embodiment of the present invention; FIG. 2 is a diagram illustrating an example of a management ledger. FIG. 2 is a diagram showing an example of vibration characteristics of steam traps of multiple types and reference models. FIG. 1 is a diagram showing an example of a process for converting the vibration value of a type I first steam trap into a steam leakage amount. FIG. 13 is a diagram showing an example of a process for converting the vibration value of a type VI first steam trap into a steam leakage amount. FIG. 2 illustrates an example of vibration characteristics of multiple models of steam traps. FIG. 13 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. FIG. 11 is a diagram showing another example of a process for converting the vibration value of a reference steam trap into the amount of steam leakage. FIG. 13 is a diagram showing another example of a process for converting the vibration value of a type I first steam trap into a steam leakage amount. FIG. 11 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. 4 is a flowchart illustrating an example of operations and processes performed by a diagnostic device when diagnosing a target steam trap.

The following describes in detail an embodiment of the present invention 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.

In plants equipped with steam piping systems, multiple steam traps are installed in appropriate locations in the piping system to discharge condensate (drain) generated within the piping system to the outside of the piping system. The performance of the steam traps is diagnosed by regular diagnosis, such as once a year. A worker performing regular diagnosis moves around the plant carrying diagnostic device 1, and uses diagnostic device 1 to diagnose the performance of each steam trap in turn. Note that diagnosis of the performance of steam traps is not limited to regular diagnosis, and may also be irregular diagnosis. The following describes an example of regular diagnosis in which the amount of steam leakage from a steam trap is diagnosed.

If it is permitted to bring data processing devices such as laptops into the plant, workers can carry the data processing device along with the diagnostic device 1 and diagnose the amount of steam leakage from each steam trap in turn. In this case, the diagnostic device 1 can transmit the diagnosis 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.

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 business vehicle or a field office, and takes only the diagnostic device 1 with him/her to diagnose the amount of steam leakage from each steam trap in turn. In this case, the diagnostic results for each steam trap are stored in the diagnostic device 1. After the worker returns to the waiting area, the diagnostic device 1 transmits the diagnostic results for the multiple steam traps stored in the diagnostic device 1 to the server device via the data processing device and the communication network.

The configuration of the diagnostic device 1 will be described in detail below. 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.

The 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 the probe 19 is pressed against the steam trap, the vibration sensor 11 outputs an analog signal indicating the vibration of the steam trap transmitted to the probe 19 to the amplifier circuit 12.

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.

The gain switching circuit 18 sets the gain when the amplifier circuit 12 amplifies the output signal of the vibration sensor 11. Specifically, the gain switching circuit 18 is composed of a switch circuit that switches the resistance value of the resistive elements that make up the amplifier circuit 12. The gain switching circuit 18 switches the resistance value of the resistive elements that make up the amplifier circuit 12 to a resistance value that corresponds to the gain specified by a gain setting unit 80, which will be described later. In this way, the gain switching circuit 18 sets the gain specified by the gain setting unit 80 as the gain when the amplifier circuit 12 amplifies the output signal of the vibration sensor 11.

The operation unit 13 is composed of operation switches and the like that allow the operator to input various information. The display unit 14 is composed of a liquid crystal display, an organic EL display, or the like. However, the operation unit 13 and the display unit 14 may be integrated by using a touch panel display. The display unit 14 displays various 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.

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

The management ledger 91 is created in the data processing device. Specifically, the 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.

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 described as coordinates that indicate the area in which each steam trap is installed when the plant is divided into multiple areas.

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.

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

The multiple steam traps that may be installed within a plant are classified into multiple types of steam traps 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.

In addition, each type of steam trap is classified into multiple models of steam traps based on the maximum condensate discharge amount. The model contains information (e.g., M11) that specifies the maximum condensate discharge amount of the steam trap.

In addition, attribute information I3 may also include information indicating other attributes of the steam trap.

Characteristics information I4 is information about 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 amount of steam leakage in each steam trap.

Vibration characteristic information is information that 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, it is assumed that 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 a steam trap and the vibration value. The vibration characteristics of a steam trap differ depending on the type and model.

For example, FIG. 2 shows an example in which information indicating the vibration characteristic G41 of a steam trap of 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 of type I and reference model M11 is described as vibration characteristic information corresponding to two steam traps of reference models M11 and M12 classified as type I. Details of the vibration characteristic information will be described later.

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

For example, FIG. 2 shows an example in which the type correction coefficient used when diagnosing a type I steam trap is set to "C1." Similarly, FIG. 2 shows examples in which the type correction coefficients used when diagnosing types II, III, V, and VI steam traps are set to "C2," "C3," "1/C5," and "1/C6." FIG. 2 also shows an example in which the type correction coefficient used when diagnosing a type IV steam trap is set to "1." Details of the type correction coefficients will be described later.

The model correction coefficient is a setting value used in the amplifier unit 40 and conversion unit 60 described below when diagnosing a steam trap of a type different from the reference type IV and a model different from the reference model.

For example, FIG. 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." FIG. 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.

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 each type and reference model different from the reference type IV will be referred to as the first steam trap. Steam traps of each type and model different from the reference type IV will be referred to as the second steam trap.

In the example of 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.

In the management ledger 91 of FIG. 2, the order of the multiple steam traps is the order of diagnosis. However, the order of the multiple steam traps in the management ledger 91 is not limited to this, and may be in descending or ascending order of the trap numbers, etc.

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.

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.

The IF unit 17 is composed of an input/output terminal to which a flash memory 7 such as an SD card or a USB memory is detachably connected. When the flash memory 7 is connected to the IF unit 17, the IF unit 17 inputs and outputs information between the flash memory 7 and the control unit 10.

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 out 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 memory 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 operator performing the periodic diagnosis returns to the waiting area and then connects the flash memory 7 to the data processing device. Then, the operator performs an operation in the data processing device to obtain the updated management ledger 91 from the flash memory 7 and transmit the obtained updated management ledger 91 to the server device.

The control unit 10 is composed of a microcomputer that includes a CPU (Central Processing Unit) (not shown) that executes predetermined calculation processing, a non-volatile memory (not shown) such as an EEPROM that stores a predetermined control program, a RAM (Random Access Memory) (not shown) for temporarily storing data, and peripheral circuits for these.

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

The control unit 10 also 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 the control program stored in the non-volatile memory.

The gain setting unit 80 refers to the management ledger 91 stored in the memory unit 15 and acquires the type correction coefficient associated with the steam trap to be diagnosed. The gain setting unit 80 determines the product of the acquired type correction coefficient and a predetermined reference gain as the initial value of the gain when the amplifier circuit 12 amplifies 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 to be used by the amplifier circuit 12.

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.

The amplifier 40 refers to the management ledger 91 stored in the 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 the AD converter 20 to the conversion unit 60 without amplifying it. On the other hand, when the object to be diagnosed is the second steam trap, the amplifier 40 obtains a model correction coefficient corresponding to the steam trap to be diagnosed from the management ledger 91. The amplifier 40 sets the model correction coefficient as the amplification factor and amplifies the output signal of the AD converter 20 by the amplification factor.

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

On the other hand, when diagnosing the first steam trap with trap number T1 in the management ledger 91 of FIG. 2, the gain setting unit 80 obtains the model correction coefficient "C1" corresponding to the first 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 when the amplifier circuit 12 amplifies the output signal of the vibration sensor 11, and instructs the gain switching circuit 18 to set the initial value of the gain as the gain used by the amplifier circuit 12. Since the target of diagnosis is the reference steam trap, the amplifier unit 40 outputs the output signal of the AD converter 20 to the conversion unit 60 without amplifying it.

When diagnosing the second steam trap with trap number T4 in the management ledger 91 of FIG. 2, the gain setting unit 80 obtains the 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 when the amplifier circuit 12 amplifies the output signal of the vibration sensor 11, and instructs the gain switching circuit 18 to set the initial value of the gain as the gain used by the amplifier circuit 12. Since the diagnosis target is the second steam trap, the amplifier unit 40 obtains the 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 the amplification factor "C120".

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

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

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

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.

Specifically, the correction unit 90 detects that the conversion unit 60 is overflowing when the conversion unit 60 converts the vibration value indicated by the input signal to the conversion unit 60 a predetermined number of times in succession into a steam leakage amount 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 the vibration value indicated by the input signal to the conversion unit 60 a predetermined number of times in succession into a steam leakage amount equal to or less than the lower limit amount that can be converted by the conversion unit 60.

When the correction unit 90 reduces the gain used by the amplifier circuit 12 until it detects that the conversion unit 60 has not overflowed, it further increases the amplification factor used by the amplifier unit 40 to the maximum extent possible without causing the conversion unit 60 to overflow. On the other hand, when the correction unit 90 increases the gain used by the amplifier circuit 12 until it detects that the conversion unit 60 has not overflowed, it further decreases the amplification factor used by the amplifier unit 40 to the maximum extent possible without causing the conversion unit 60 to overflow. Details of the correction unit 90 will be described later.

The following describes the vibration characteristic information, reference gain, type correction coefficient and model correction coefficient set in the management ledger 91 (Figure 2), and details of the conversion unit 60.

Figure 3 shows an example of the vibration characteristics of steam traps of multiple types and reference models. In Figure 3, the horizontal axis shows the amount of steam leakage from the steam trap, and the vertical axis shows the vibration value (vibration level) of the steam trap.

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 type I first steam trap. The other first steam traps will be abbreviated in the same way. Vibration characteristics G21, G31, G51, G61 are the vibration characteristics (second vibration characteristics) of first steam traps of types II, III, V, and VI.

Furthermore, hereafter, the six vibration characteristics G11, G21, G31, G41, G51, and G61 will be abbreviated as vibration characteristics G11 to G61. Vibration characteristics G11 to G61 are derived based on experimental values using steam traps of each type and standard model.

Vibration value "L40" is the vibration value when the vibration of the reference 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 vibration of the steam trap reaches a maximum and it cannot vibrate at a larger amplitude. 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.

As shown by 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.

In the management ledger 91 (Figure 2), the vibration characteristic information corresponding to each steam trap of type IV describes a quadratic function or exponential function indicating the vibration characteristic G41. In the management ledger 91 (Figure 2), the vibration characteristic information corresponding to each steam trap of types II, III, V, and VI describes a quadratic function or exponential function indicating the vibration characteristics G21, G31, G51, and G61 of the first steam trap of the same type as each steam trap.

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 the AD converter 20 (Figure 1) matches the range of vibration values indicated by the vibration characteristic G41 ("0" to "L40"). In other words, the reference gain is set so that when diagnosing the reference steam trap, the output signal of the AD converter 20 (Figure 1) is not amplified in the amplifier 40.

For this reason, when diagnosing the reference steam trap, the reference gain is set as the initial value of the gain used by the amplifier circuit 12. Therefore, in the management ledger 91 (Figure 2), the type correction coefficient corresponding to the reference steam trap is recorded as "1", which is the ratio of the gain used by the amplifier circuit 12 (reference gain) to the reference gain.

As a result, when diagnosing the reference steam trap, the gain setting unit 80 obtains the model correction coefficient "1" corresponding to the reference steam trap (reference type IV steam trap) from the management ledger 91 (Figure 2), 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 the amplifier circuit 12. The gain setting unit 80 instructs the gain switching circuit 18 to set the determined initial value of the gain as the gain to be used by the amplifier circuit 12.

When diagnosing a reference steam trap, the conversion unit 60 obtains vibration characteristic information corresponding to the reference steam trap from the management ledger 91 (Figure 2) stored in the memory unit 15. When diagnosing a reference steam trap, the amplifier unit 40 outputs the output signal of the AD converter 20 to the conversion unit 60 without amplifying it. Therefore, the conversion unit 60 substitutes the vibration value (e.g., L1) of the reference steam trap indicated by the output signal of the 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 the steam leakage amount (e.g., B1) corresponding to the vibration value.

On the other hand, when diagnosing the first steam trap of type I, the initial value of the gain used by the amplifier circuit 12 is set to the reference gain, just as when diagnosing the reference steam trap. In this case, since the diagnosis target 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. For this reason, even though signals indicating vibration values in the range from "0" to "L40" can be input to the conversion unit 60, only signals indicating vibration values in the range from "0" to "L10" indicated by the vibration characteristic G11 of the first steam trap of type I are input.

Here, for example, let us say that the vibration value "L40" is 400 dB and the vibration value "L10" is 40 dB. Also, let us say that due to the performance of the CPU, the conversion unit 60 is capable of converting 400 vibration values into 400 steam leakage amounts.

In this case, when diagnosing the reference steam trap, the range of vibration values indicated by the signal input to the conversion unit 60 is in the range of 0 dB to 400 dB, so the conversion unit 60 can convert 400 different vibration values into 400 different steam leakage amounts 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 the conversion unit 60 is narrowed to the range of 0 dB to 40 dB. As a result, the conversion unit 60 can only convert 40 different vibration values into 40 different steam leakage amounts in 1 dB increments.

In this way, if the output signal of the vibration sensor 11 is amplified by the reference gain in the amplifier circuit 12, and the output signal of the AD converter 20 is not amplified, and the vibration value of the first steam trap of type I indicated by the output signal of the AD converter 20 is converted to the amount of steam leakage in the conversion unit 60, the accuracy of the conversion in the conversion unit 60 will be worse than when diagnosing the reference steam trap. For this reason, the initial value of the gain used by the amplifier circuit 12 when diagnosing the first steam trap is set so that the accuracy of the conversion in the conversion unit 60 is the same as when diagnosing the reference steam trap.

Specifically, when diagnosing a type I first steam trap, the initial value of the gain used by the 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 the management ledger 91 (Figure 2), the type correction coefficient corresponding to the type I first steam trap is recorded with the ratio "C1", which is a multiplier for the reference gain.

As a result, when diagnosing a type I first steam trap, the gain setting unit 80 obtains the type correction coefficient "C1" corresponding to the type I steam trap from the management ledger 91 (Figure 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 the amplifier circuit 12. The gain setting unit 80 instructs the gain switching circuit 18 to set the determined initial value of the gain as the gain to be used by the amplifier circuit 12.

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

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

When diagnosing a type I first steam trap, the conversion unit 60 acquires vibration characteristic information corresponding to the first steam trap from the management ledger 91 (Figure 2) stored in the memory unit 15. The conversion unit 60 substitutes the vibration value (e.g., L2) of the first steam trap indicated by the output signal of the 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 the steam leakage amount (e.g., B2) corresponding to the vibration value.

As described above, when diagnosing a type II first steam trap, the initial value of the gain used by the amplifier circuit 12 is set to the product of the reference gain and the ratio "C2 (=L40/L20)" of the vibration value "L20" (Figure 3) when the vibration of the first steam trap is saturated to the vibration value "L40" (Figure 3) when the vibration of the reference steam trap is saturated. Therefore, in the management ledger 91 (Figure 2), the type correction coefficient corresponding to the type II first steam trap is recorded with the ratio "C2", which is a multiplier for the reference gain.

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

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 diagnosis target 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. For this reason, a signal indicating a vibration value in the range from "0" to "L40" is input to the conversion unit 60. However, even though the conversion unit 60 is capable of outputting a signal indicating a steam leakage amount in the range from "0" to "B40", it will only output a signal indicating a steam leakage amount in the range from "0" to "B60" indicated by the vibration characteristic G61 of type VI.

For ease of explanation, let us assume 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, let us assume that the conversion unit 60 is capable of converting 400 vibration values into 400 steam leakage amounts due to the performance of the CPU, as described above.

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

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

Specifically, the steam leakage amount "B60" (second leakage amount) when the vibration of the first steam trap of type VI is saturated is smaller than the steam leakage amount "B40" (first leakage amount) when the vibration of the reference steam trap is saturated. Therefore, when diagnosing the first steam trap of type VI, the initial value of the gain used by the amplifier circuit 12 is set to the product of the reciprocal "1/C6 (=B60/B40)" of the ratio "C6 (=B40/B60)" of the steam leakage amount "B40" when the vibration of the reference steam trap is saturated to the steam leakage amount "B60" when the vibration of the steam trap of type VI is saturated, and the reference gain. Therefore, the reciprocal "1/C6" of the ratio "C6", which is a multiplier for the reference gain, is written in the type correction coefficient corresponding to the steam trap of type VI in the management ledger 91 (Figure 2).

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

Figure 4B is a diagram showing an example of a process for converting the vibration value of the first steam trap of type VI into the amount of steam leakage. In order to diagnose the first steam trap of type VI, the initial value of the gain used by the amplifier circuit 12 is set to the product of the type correction coefficient "1/C6" and the reference gain. In this case, the signal amplified in the amplifier circuit 12 is converted into a digital signal in the AD converter 20, and then output to the converter 60 without being amplified in the amplifier unit 40. As a result, as shown in Figure 4B, the maximum value of the amount of steam leakage indicated by the output signal of the converter 60 is the amount of steam leakage "B60" when the vibration of the first steam trap of type VI is saturated. In other words, when diagnosing the first steam trap of type VI, the converter 60 can convert the 400 vibration values indicated by the output signal of the AD converter 20 into 400 steam leakage amounts in units of "1/C6" times that when diagnosing the reference steam trap of type IV.

In the above example, the conversion unit 60 can convert the 400 vibration values indicated by the output signal of the AD converter 20 into 400 steam leakage rates in units of 0.5 (=1/C6=B60/B40=200/400) tons/year. This ensures that the conversion accuracy of the conversion unit 60 when diagnosing the Type VI first steam trap is the same as when diagnosing the reference steam trap.

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

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

When diagnosing a first steam trap of types II, III, or V, the conversion unit 60 also obtains vibration characteristic information associated with the first steam trap to be diagnosed from the management ledger 91 (Figure 2) stored in the memory unit 15. The conversion unit 60 then substitutes the vibration value of the first steam trap to be diagnosed, indicated by the output signal of the AD converter 20, into a quadratic function or exponential function indicating the vibration characteristic indicated by the vibration characteristic information, and converts it into the amount of steam leakage corresponding to the vibration value.

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

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 a first steam trap of type V and reference model M51. Vibration characteristic G52 is the vibration characteristic of a second steam trap of type V and model M52. Vibration characteristic G53 is the vibration characteristic of a second steam trap of type V and model M53. Model M52 has a maximum condensate discharge amount greater than reference model M51 and less than model M53.

As shown in Figure 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.

In FIG. 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 amount is "B50". The steam leakage amount "B50" is the steam leakage amount 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 amount is "B52".

The ratio C520 and the ratio C522 both had a value of X and were consistent. Incidentally, "to match" means to match within a specified error range, and this also applies to the following explanations. In this way, 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.

In addition, in FIG. 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".

The ratios C530 and 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.

Similarly, the same results as above were obtained from the vibration characteristics of the first steam traps of types I-IV and VI and the second steam traps of each model different from the reference models of types I-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.

Here, for example, when diagnosing a second steam trap of type V and model M52 (Figure 2), the amplification factor used by the amplifier unit 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 the amplifier unit 40 is the vibration value "L510" when the vibration of the first steam trap is saturated, which is a vibration value greater than the vibration value "L520" when the vibration of the second steam trap is saturated. Therefore, the accuracy of the conversion in the conversion unit 60 when diagnosing the second steam trap is worse than when diagnosing the first steam trap.

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

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

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 characteristic of the second steam trap to the vibration value of the vibration characteristic of the first steam trap of the same model as the second steam trap (for example, C520 (= L510/L520)).

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

In this case, the conversion unit 60 obtains vibration characteristic information and a model correction coefficient corresponding to the second steam trap from the management ledger 91 (Figure 2). The vibration characteristic information indicates the vibration characteristic G11 (Figure 5) (second vibration characteristic) of the 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)).

For this reason, 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.

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

The vibration characteristic information stored in the management ledger 91 is not limited to information indicating a quadratic function or exponential function that indicates 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.

Figure 7 shows another example of a process for converting the vibration value of the reference steam trap into a steam leakage amount. In accordance with the above, when diagnosing the reference steam trap, the conversion unit 60 may substitute the vibration value (e.g., L1) of the reference steam trap indicated by the output signal of the AD converter 20 into a function G411 that is a linear approximation of the vibration characteristic G41 indicated by the vibration characteristic information, as shown in Figure 7, to convert the vibration value into a steam leakage amount (e.g., B411) corresponding to the vibration value.

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

Similarly, when diagnosing the first steam trap of type II, III, V, or VI, the conversion unit 60 may substitute the vibration value of the first steam trap of type II, III, V, or 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, to convert the vibration value into the amount of steam leakage corresponding to the vibration value.

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

Similarly, when diagnosing a second steam trap of another type and model, the conversion unit 60 may convert 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 from the product of the vibration characteristics indicated by the vibration characteristic information and the inverse 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 and the inverse of the model correction coefficient, to convert the vibration value into the amount of steam leakage corresponding to the vibration value.

The procedure for periodic diagnosis using the diagnostic device 1 will be described below. The worker performing the periodic diagnosis moves around the plant carrying the diagnostic device 1 (and the data processing device, if permitted), and uses the diagnostic device 1 to sequentially diagnose the amount of steam leakage from each steam trap. At this time, the worker operates the operation unit 13, causing the control unit 10 to display the management ledger 91 stored in the memory unit 15 on the display unit 14. This allows the worker to recognize the diagnosis sequence of the multiple steam traps installed in the plant, and the absolute position information I1, identification information I2, and attribute information I3 of each steam trap. The worker moves to the installation location of the target steam trap to be diagnosed this time, according to the diagnosis sequence and absolute position that can be recognized from the displayed management ledger 91.

Figure 10 is a flowchart showing an example of the operations and processes performed by the 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, the operator operates the operation unit 13 to select one target steam trap to be diagnosed this time from among the multiple target steam traps included in the 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 the operation unit 13 to the control unit 10.

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

Next, the amplifier 40 refers to the 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, the amplifier 40 obtains a model correction coefficient corresponding to the target steam trap from the management ledger 91, and sets the model correction coefficient as the amplification factor (step S13).

Next, the operator presses the probe 19 (Figure 1) of the diagnostic device 1 against the steam trap to be diagnosed (step S14).

When the probe 19 (Figure 1) of the diagnostic device 1 is pressed against the target steam trap, the adjustment unit 30 detects whether the AD converter 20 is overflowing (step S15).

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

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 stored in advance in the storage unit 15 by the administrator of the diagnostic device 1 operating the operation unit 13.

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

Specifically, in step S15, the adjustment unit 30 detects that the AD converter 20 is overflowing because the value indicated by the output signal of 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 a gain that is decreased by a predetermined amount from the current gain as the gain to be used by the amplifier circuit 12.

Meanwhile, in step S15, the adjustment unit 30 detects that the AD converter 20 is overflowing because the value indicated by the output signal of 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 a gain that is increased by a predetermined amount from the current gain as the gain to be used by the amplifier circuit 12.

The method by which the adjustment unit 30 increases and 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.

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

When 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 amplifier unit 40. As a result, the amplifier 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 amplifier unit 40 into the amount of steam leakage (step S18).

Next, the correction unit 90 detects that the conversion unit 60 is overflowing when the conversion unit 60 converts the vibration value indicated by the input signal of the conversion unit 60 a predetermined number of times (e.g., three times) in succession into a steam leakage amount equal to or greater than the upper limit amount that can be converted by the conversion unit 60, and when the conversion unit 60 converts into a steam leakage amount equal to or less than the lower limit amount that can be converted by the conversion unit 60 (YES in step S19).

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

On the other hand, the correction unit 90 detects that the conversion unit 60 is not overflowing 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 equal to or greater than the upper limit amount that can be converted by the conversion unit 60 and does not convert the vibration value indicated by the input signal to the conversion unit 60 into a steam leakage amount equal to or less than the lower limit amount that can be converted by the conversion unit 60 for the predetermined number of consecutive times (NO in step S19).

If the correction unit 90 detects in step S19 that the conversion unit 60 is overflowing (YES in step S19), it adjusts the gain used by the amplifier circuit 12 (step S20).

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 amount 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 the instruction, the gain setting unit 80 instructs the gain switching circuit 18 to set a gain that is decreased by a predetermined amount from the current gain as the gain to be used by the amplifier circuit 12.

Meanwhile, 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 below the lower 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 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 a gain that is increased by a predetermined amount from the current gain as the gain to be used by the amplifier circuit 12.

The method by which the correction unit 90 increases and 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.

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

If the correction unit 90 detects in step S19 that the conversion unit 60 has not overflowed (NO in step S19), it adjusts the amplification factor used by the amplification unit 40 to the maximum extent possible without causing the conversion unit 60 to overflow (step S21).

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 amplifier 40 to decrease the gain by a predetermined amount, thereby decreasing the gain used by the amplifier 40 by the predetermined amount, and then repeats the process of detecting whether the converter 60 has overflowed, as in step S19. Then, if the correction unit 90 detects that the converter 60 has overflowed during this repetition, it sets the gain of the amplifier 40 to the gain set immediately before the gain set at the time of the detection.

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

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.

In addition, if the correction unit 90 does not perform step S20 after step S18 and before performing step S21, the conversion unit 60 has not overflowed, so the amplification factor is not changed in step S21.

After step S21, the conversion unit 60 converts the vibration value of the target steam trap into the steam leakage amount of the target steam trap to calculate the steam leakage amount of the target steam trap (step S22). The control unit 10 outputs the steam leakage amount 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.

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

The control unit 10 also adds information indicating the amount of steam leakage from the target steam trap calculated in step S22 to the location in the management ledger 91 that corresponds to the target steam trap. The control unit 10 stores (outputs) the management ledger 91 after the addition in the memory unit 15. As a result, the control unit 10 updates the management ledger 91 stored in the memory unit 15.

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

On the other hand, suppose that the operator is carrying the data processing device and has completed diagnosis of all target steam traps. In this case, the control unit 10 acquires the updated management ledger 91 stored in the memory unit 15, and transmits an instruction to the data processing device via the communication unit 16 to transmit the 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.

In this manner, in this embodiment, when the AD converter 20 overflows, the gain is decreased or increased until the 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 the AD converter 20. This allows each of the multiple steam traps to be treated as the target steam trap to be diagnosed, and the output signal of the AD converter 20 can be output as a signal indicating the appropriate vibration value of the target steam trap.

In addition, 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. Also, in step S21 (Figure 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 accuracy as possible while avoiding the conversion unit 60 from overflowing.

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

1: Diagnostic device 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 (10)

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 for converting an output signal of the amplifier circuit into a digital signal;
an adjustment unit that, when detecting 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 an output signal of the AD converter when it detects that the AD converter is not overflowing;
A diagnostic device comprising: the adjustment unit detects that the AD converter is overflowing when a value indicated by the output signal of the AD converter is equal to a predetermined upper limit value or when a 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 . the plurality of steam traps are classified into a plurality of types of steam traps;
Each type of steam trap is divided into a plurality of models of steam traps, including a first steam trap of a given 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 is saturated in the first steam trap of a predetermined reference type to a vibration value when vibration is saturated in the first steam trap of the same type as the target steam trap.
The diagnostic device according to claim 1 or 2. an amplifier that amplifies an output signal of the AD converter using, as an amplification factor, a model correction coefficient that is a ratio of a vibration value of a second vibration characteristic that indicates a relationship between a steam leakage amount and a 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 a relationship between a steam leakage amount and a 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 a steam leakage amount of 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: The diagnostic device according to claim 4 , further comprising a correction unit that, when detecting that the conversion unit has overflowed, causes the setting unit to decrease or increase the gain until it detects that the conversion unit has not overflowed. The correction unit is
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 a maximum extent within a range in which the conversion unit does not overflow,
When the setting unit increases the gain until it is detected that the conversion unit does not overflow, 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 of claim 5. The correction unit is
When the conversion unit converts the vibration value indicated by the input signal of the conversion unit into a steam leakage amount equal to or greater than the upper limit amount that can be converted by the conversion unit a predetermined number of times in succession,
When the conversion unit converts the vibration value indicated by the input signal of the conversion unit into a steam leakage amount equal to or less than a lower limit amount that can be converted by the conversion unit a predetermined number of times in succession,
Detecting that the conversion unit is overflowing;
The diagnostic device of claim 5. The setting unit is
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 an initial value of the gain;
The diagnostic device of claim 3. the conversion unit, when the target steam trap is the second steam trap, 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. 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 from 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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