Pipe deterioration diagnosis device

Abstract

To provide a diagnosis device capable of diagnosing deterioration of a pipe through which steam flows.SOLUTION: A pipe deterioration diagnosis device comprises: a vibration sensor that detects vibration of a pipe to be diagnosed caused by flowing steam through the pipe, and outputs an analog signal according to the vibration; a variable gain amplifier circuit that amplifies and outputs the analog signal; an AD conversion circuit with a predetermined dynamic range that converts an output signal of the amplifier circuit into a digital signal; a diagnosis unit that diagnoses deterioration of the pipe based on flow information indicating a steam flow rate and a vibration value indicated by the digital signal; and a gain setting unit that sets a gain. The gain setting unit sets the gain in initial setup performed before the pipe deteriorates, thereby setting the vibration value when steam at a reference flow rate is flowed through the pipe to a median value of the dynamic range.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a piping deterioration diagnostic device. [Background technology]

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

[0003] If the sealing performance of a steam trap is impaired due to aging or malfunction, the steam in the steam piping system will leak to the outside through the steam trap, resulting in unnecessary steam loss. For this reason, the condition of steam traps is inspected periodically, such as once a year.

[0004] Patent Document 1 listed below discloses a measuring device and a diagnostic device for diagnosing the condition of steam traps. The measuring device is a portable measuring device, and the diagnostic device is a tablet terminal or laptop computer, etc., and the measuring device and diagnostic device are capable of wireless communication with each other. The measuring device includes a temperature sensor that measures the surface temperature of each steam trap, a vibration sensor that measures the vibration intensity of each steam trap, a memory unit that stores measurement data output from the temperature sensor and the vibration sensor, a communication unit that transmits the measurement data to the diagnostic device, and a display unit. The diagnostic device diagnoses the condition (normal or abnormal) of each steam trap based on the measurement data received from the measuring device and transmits diagnostic data indicating the results of the diagnosis to the measuring device. The measuring device displays the results of the diagnosis for each steam trap on the display unit based on the diagnostic data received from the diagnostic device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-84418 Summary of the Invention [Problem to be solved by the invention]

[0006] The diagnostic device according to the background art can diagnose the deterioration state of a steam trap, but cannot diagnose the deterioration state of a pipe through which steam flows.

[0007] An object of the present invention is to provide a diagnostic device capable of diagnosing deterioration of piping through which steam flows. [Means for solving the problem]

[0008] A diagnostic device according to a first aspect of the present invention is a piping deterioration diagnostic device that diagnoses deterioration of a piping through which steam flows, and includes: a vibration sensor that detects vibrations of the piping to be diagnosed caused by flowing steam through the piping and outputs an analog signal corresponding to the vibration; an amplifier circuit with a variable gain that amplifies and outputs the analog signal; an AD conversion circuit with a predetermined dynamic range that converts the output signal of the amplifier circuit into a digital signal; a diagnostic unit that diagnoses deterioration of the piping based on flow rate information indicating the flow rate of the steam and a vibration value indicated by the digital signal; and a gain setting unit that sets the gain, wherein the gain setting unit sets the gain in initial setting performed before the piping deteriorates, thereby setting the vibration value when steam at a reference flow rate is flowed through the piping to the median value of the dynamic range.

[0009] According to the first aspect, it is possible to diagnose deterioration of a pipe based on flow rate information indicating the flow rate of steam and a vibration value indicated by a digital signal. In addition, the gain setting unit sets the gain so that the vibration value when steam at a reference flow rate is flowed through the pipe is the median value of the dynamic range, so it is possible to detect both deterioration of the pipe in a manner in which the vibration value is lower than the normal value and deterioration of the pipe in a manner in which the vibration value is higher than the normal value.

[0010] A diagnostic device according to a second aspect of the present invention is the first aspect, further comprising a memory unit that stores characteristic information of normal characteristics that indicates the relationship between the flow rate and the vibration value before the piping deteriorates, and the diagnostic unit, if the vibration value is below the normal characteristic during the diagnosis, identifies corrosion on the inner surface of the piping as the cause of the deterioration of the piping, and if the vibration value is above the normal characteristic, identifies deposition of scale on the inner surface of the piping as the cause of the deterioration of the piping.

[0011] According to the second aspect, both corrosion of the inner surface of the pipe and deposition of scale on the inner surface of the pipe can be detected as causes of deterioration of the pipe. [Effects of the Invention]

[0012] According to the present invention, it is possible to diagnose deterioration of piping through which steam flows. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing a simplified configuration of a pipe deterioration diagnosis device according to an embodiment of the present invention; [Figure 2A] FIG. 2 is a cross-sectional view schematically showing the internal state of a deteriorated pipe. [Figure 2B] FIG. 2 is a cross-sectional view schematically showing the internal state of a deteriorated pipe. [Figure 3] 4 is a flowchart showing an operation executed by the pipe deterioration diagnostic device at the time of initial setting. [Figure 4] FIG. 10 is a diagram showing the relationship between the flow rate and the vibration value. [Figure 5] 4 is a flowchart showing the operation performed by the pipe deterioration diagnostic device during actual operation. [Figure 6] FIG. 10 is a diagram showing the relationship between the flow rate and the vibration value. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Elements with the same reference numerals in different drawings indicate the same or corresponding elements.

[0015] Fig. 1 is a simplified diagram showing the configuration of a piping deterioration diagnosis device 1 according to an embodiment of the present invention. Fig. 1 shows the configuration of the piping deterioration diagnosis device 1 as well as a cross-sectional view of a piping 100 to be diagnosed. The piping deterioration diagnosis device 1 diagnoses the time-dependent deterioration of the piping 100 through which steam flows in a plant or the like equipped with a steam piping system. The piping deterioration diagnosis device 1 may be fixedly installed on the piping 100 to be diagnosed, or may be configured as a portable diagnosis device that can be carried by an operator.

[0016] 2A and 2B are cross-sectional views showing a schematic diagram of the internal state of deteriorated pipe 100. Because steam generated using industrial water containing many impurities may flow through pipe 100, pipe 100 deteriorates over time with long-term use. FIG. 2A shows a deteriorated state in which the inner surface of pipe 100 has corroded, forming a corrosion layer 201 over the entire inner surface. FIG. 2B shows a deteriorated state in which scale 202 has partially deposited on the inner surface of pipe 100. Scale 202 is a precipitate of ions and the like that were dissolved in water, and typical components include calcium carbonate (CaCO3) or talc (Mg3SiO4). 10 (OH)2).

[0017] When steam flows through the pipe 100, the pipe 100 vibrates, and the vibration value of the pipe 100 increases as the flow rate of the steam per unit time (i.e., flow velocity) increases. When a corrosion layer 201 is formed on the entire inner surface of the pipe 100 (FIG. 2A), the inner diameter of the pipe 100 is substantially reduced, and therefore the vibration value corresponding to the flow rate of the steam flowing through the pipe 100 tends to decrease compared to before deterioration. On the other hand, when scale 202 is locally deposited on the inner surface of the pipe 100 (FIG. 2B), the vibration value corresponding to the flow rate of the steam flowing through the pipe 100 tends to increase compared to before deterioration. Note that once the corrosion layer 201 is formed, it is not removed naturally. However, even if scale 202 is deposited on the inner surface of the pipe 100, the scale 202 may peel off and be removed due to the pressure of the steam flowing through the pipe 100.

[0018] Referring to FIG. 1, a pipe deterioration diagnostic device 1 includes a vibration sensor 11, an amplifier circuit 12, a control circuit 13, a communication unit 14, a display unit 15, and an input unit 16.

[0019] A vibration probe 20 is connected to the vibration sensor 11. The vibration probe 20 has the external shape of a cylindrical pipe made of, for example, stainless steel. The vibration probe 20 transmits vibrations of the pipe 100 to the vibration sensor 11 by being brought into contact with the outer surface of the pipe 100 to be diagnosed.

[0020] The vibration sensor 11 is configured using, for example, a piezoelectric acceleration sensor. The vibration sensor 11 detects vibrations of the piping 100, which is the target of diagnosis, caused by flowing steam through the piping 100, via the vibration probe 20, and converts the vibrations into an electrical signal to output an analog signal S1.

[0021] The amplifier circuit 12 outputs an amplified analog signal S2 by amplifying the analog signal S1 input from the vibration sensor 11. The amplifier circuit 12 has a variable resistor (not shown), and by adjusting the resistance value of the variable resistor based on setting information D4, the gain (amplification degree) when amplifying the analog signal S1 can be variably set.

[0022] The control circuit 13 is configured using a microcontroller, etc. The control circuit 13 includes an AD conversion circuit 31, a data processing unit 32, and a storage unit 33.

[0023] The AD conversion circuit 31 converts the analog signal S2, which is the output signal of the amplifier circuit 12, into a digital signal D1. The AD conversion circuit 31 has a predetermined dynamic range DR corresponding to the number of gradations of the vibration value. In this embodiment, the dynamic range DR corresponds to 400 gradations from the minimum vibration value L1 to the maximum vibration value L400. In this example, the median value of the dynamic range DR is the vibration value L200.

[0024] The data processing unit 32 is configured using a processor such as a CPU, etc. The data processing unit 32 has a setting unit 41 and a diagnosis unit 42 as functions realized by the processor executing a program.

[0025] The setting unit 41 functions as a gain setting unit that sets the gain of the amplifier circuit 12. The setting unit 41 performs initial setting before the piping 100 deteriorates. In the initial setting, the setting unit 41 sets the gain of the amplifier circuit 12 so that the vibration value when steam at a reference flow rate Q0 flows through the piping 100 becomes the median value (vibration value L200) of the dynamic range DR of the AD conversion circuit 31. The reference flow rate Q0 is the flow rate of steam that is expected to flow through the piping 100 during actual operation, and can be set to a desired value by the user.

[0026] After completing the setting of the gain of the amplifier circuit 12, the setting unit 41 generates a normal characteristic K0 indicating the correspondence between the plurality of flow rates Q and the plurality of vibration values ​​L before the deterioration of the piping 100. The setting unit 41 stores characteristic information D3 indicating the generated normal characteristic K0 in the storage unit 33.

[0027] The diagnostic unit 42 diagnoses the deterioration of the piping 100 over time based on flow rate information D2 indicating the flow rate Q of steam flowing through the piping 100 during actual operation, the vibration value L of the piping 100 indicated by the digital signal D1 acquired from the AD conversion circuit 31 during actual operation, and characteristic information D3 read out from the memory unit 33.

[0028] The input unit 16 is configured using any input device, and generates flow rate information D2 indicating the flow rate Q based on the set value of the flow rate Q input by the user. The flow rate Q includes a reference flow rate Q0 or a flow rate Q1 during actual operation.

[0029] In the diagnosis, if the vibration value L is less than the normal characteristic K0, the diagnosing unit 42 identifies corrosion on the inner surface of the pipe 100 as the cause of deterioration of the pipe 100, and if the vibration value L is greater than the normal characteristic K0, identifies deposition of scale 202 on the inner surface of the pipe 100 as the cause of deterioration of the pipe 100. The diagnosing unit 42 displays the diagnosis result on the display unit 15. The diagnosing unit 42 may transmit the diagnosis result from the communication unit 14 to an external management device. The management device may be a cloud server, an on-premise server, or the like. The display unit 15 and the input unit 16 may be provided in the management device instead of the pipe deterioration diagnosis device 1.

[0030] FIG. 3 is a flowchart showing the operation executed by the pipe deterioration diagnostic device 1 at the time of initial setting.

[0031] First, in step SP11, the setting unit 41 acquires, from the input unit 16, flow rate information D2 indicating the set value of the reference flow rate Q0.

[0032] Next, in step SP12, the setting section 41 arbitrarily sets the gain of the amplifier circuit 12 according to the setting information D4.

[0033] Vibration sensor 11 detects vibrations of pipe 100 caused by flowing steam at a reference flow rate Q0 through pipe 100 via vibration probe 20, and converts the vibrations into an electrical signal to output analog signal S1. Amplification circuit 12 amplifies analog signal S1 input from vibration sensor 11 by the gain set in step SP12, and outputs an amplified analog signal S2.

[0034] Next, in step SP13, the control circuit 13 acquires the analog signal S2 from the amplifier circuit 12.

[0035] Next, in step SP14, the AD conversion circuit 31 converts the analog signal S2 acquired in step SP13 into a digital signal D1.

[0036] Next, in step SP15, the setting unit 41 determines whether the vibration value L indicated by the digital signal D1 matches the median value of the dynamic range DR of the AD conversion circuit 31 (vibration value L200).

[0037] If the vibration value L does not match the median value (step SP15: NO), then in step SP16, the setting unit 41 determines whether or not the vibration value L is greater than the median value.

[0038] If the vibration value L is greater than the median value (step SP16: YES), then in step SP17 the setting unit 41 reduces the gain of the amplifier circuit 12 by a certain percentage or a certain level according to the setting information D4, and then repeats the processing from step SP13 onwards.

[0039] If the vibration value L is smaller than the median value (step SP16: NO), then in step SP18 the setting unit 41 increases the gain of the amplifier circuit 12 by a certain rate or a certain level according to the setting information D4, and then repeats the processing from step SP13 onwards.

[0040] 4 is a diagram showing the relationship between the flow rate Q and the vibration value L. The vibration value L of the piping 100 increases quadratically or exponentially as the flow rate Q increases. The characteristic K1 is a characteristic when a gain that is greater than the gain corresponding to the normal characteristic K0 is set. The characteristic K2 is a characteristic when a gain that is smaller than the gain corresponding to the normal characteristic K0 is set.

[0041] When the vibration value L is, for example, a vibration value L280 that is greater than the median value (vibration value L200), the setting unit 41 reduces the gain of the amplifier circuit 12 by a certain percentage or a certain level according to the setting information D4, as indicated by the arrow A1.

[0042] When the vibration value L is, for example, vibration value L170, which is smaller than the median value (vibration value L200), the setting unit 41 increases the gain of the amplifier circuit 12 by a certain rate or a certain level according to the setting information D4, as indicated by arrow A2.

[0043] By repeatedly performing such gain resetting processing, the vibration value L eventually coincides with the median value (vibration value L200).

[0044] If the vibration value L matches the median value (step SP15: YES), then in step SP19, the setting unit 41 fixes the gain of the amplifier circuit 12 to the set value at that time, varies the flow rate Q, and plots the vibration value L corresponding to each flow rate Q, thereby generating a normal characteristic K0. The setting unit 41 stores characteristic information D3 indicating the generated normal characteristic K0 in the memory unit 33.

[0045] FIG. 5 is a flowchart showing the operation performed by the pipe deterioration diagnostic device 1 during actual operation.

[0046] First, in step SP21, the diagnosis unit 42 acquires from the input unit 16 flow rate information D2 indicating the set value of the flow rate Q1 during actual operation.

[0047] Next, in step SP22, the diagnosis unit 42 reads out and acquires the characteristic information D3 from the storage unit 33.

[0048] Vibration sensor 11 detects vibrations of pipe 100 caused by flowing steam at a flow rate Q1 through pipe 100 via vibration probe 20, and converts the vibrations into an electrical signal to output analog signal S1. Amplification circuit 12 amplifies analog signal S1 input from vibration sensor 11 by a gain set in the initial setting, and outputs an amplified analog signal S2.

[0049] Next, in step SP23, the control circuit 13 acquires the analog signal S2 from the amplifier circuit 12.

[0050] Next, in step SP24, the AD conversion circuit 31 converts the analog signal S2 acquired in step SP23 into a digital signal D1.

[0051] Next, in step SP25, the diagnosis unit 42 determines whether or not the vibration value X indicated by the digital signal D1 coincides with the vibration value L on the normal characteristic K0 corresponding to the flow rate Q1.

[0052] If the vibration value X matches the vibration value L on the normal characteristic K0 (step SP25: YES), then in step SP26, the diagnosing unit 42 determines that the piping 100 is not deteriorated.

[0053] If the vibration value X does not match the vibration value L on the normal characteristic K0 (step SP25: NO), then in step SP27, the diagnosing unit 42 determines whether the vibration value X is greater than the vibration value L on the normal characteristic K0.

[0054] If the vibration value X is greater than the vibration value L on the normal characteristic K0 (step SP27: YES), then in step SP28, the diagnostic unit 42 determines that the piping 100 has deteriorated and that the cause of the deterioration is the deposition of scale 202 on the inner surface of the piping 100.

[0055] If the vibration value X is smaller than the vibration value L on the normal characteristic K0 (step SP27: NO), then in step SP29, the diagnosing unit 42 determines that the piping 100 has deteriorated and that the cause of the deterioration is corrosion of the inner surface of the piping 100.

[0056] FIG. 6 is a diagram showing the relationship between the flow rate Q and the vibration value X. The vibration value X2 is greater than the vibration value X1 on the normal characteristic K0 corresponding to the flow rate Q1. In this case, the diagnosis unit 42 determines that the cause of the deterioration of the piping 100 is the deposition of scale 202 on the inner surface of the piping 100. The vibration value X3 is smaller than the vibration value X1 on the normal characteristic K0 corresponding to the flow rate Q1. In this case, the diagnosis unit 42 determines that the cause of the deterioration of the piping 100 is corrosion of the inner surface of the piping 100.

[0057] Following steps SP28 and SP29, in step SP30, the diagnosing unit 42 displays on the display unit 15 the fact that the piping 100 has deteriorated and the deterioration information indicating the cause of the deterioration.

[0058] According to this embodiment, deterioration of the piping 100 can be diagnosed based on flow rate information D2 indicating the steam flow rate Q1 and the vibration value L indicated by the digital signal D1. Furthermore, the setting unit 41 (gain setting unit) sets the gain of the amplifier circuit 12 so that the vibration value L when steam at the reference flow rate Q0 flows through the piping 100 becomes the median value (L200) of the dynamic range DR, and therefore it is possible to detect both deterioration of the piping 100 in which the vibration value is lower than the normal value and deterioration of the piping 100 in which the vibration value is higher than the normal value.

[0059] Furthermore, according to this embodiment, both corrosion of the inner surface of the pipe 100 and deposition of scale 202 on the inner surface of the pipe 100 can be detected as factors causing deterioration of the pipe 100. [Explanation of symbols]

[0060] 1. Piping deterioration diagnostic device 11 Vibration Sensor 12 Amplification circuit 13 Control circuit 31 AD conversion circuit 32 Data processing section 33 Storage section 41 Setting section 42 Diagnostic Department 100 Piping S1, S2 analog signal D1 Digital signal D2 flow rate information D3 Characteristics Information K0 normal characteristics DR Dynamic Range L (L1~L400) Vibration value Q0 Reference flow rate Q1 Flow rate

Claims

1. A piping deterioration diagnostic device for diagnosing deterioration of piping through which steam flows, a vibration sensor that detects vibrations of a pipe that is a target of diagnosis caused by flowing steam through the pipe and outputs an analog signal corresponding to the vibrations; an amplifier circuit with a variable gain that amplifies and outputs the analog signal; an AD conversion circuit having a predetermined dynamic range for converting an output signal of the amplifier circuit into a digital signal; a diagnosing unit that diagnoses deterioration of the piping based on flow rate information indicating the flow rate of the steam and the vibration value indicated by the digital signal; a gain setting unit that sets the gain; Equipped with the gain setting unit sets the gain in an initial setting executed before the piping deteriorates, thereby setting the vibration value when steam at a reference flow rate is flowed through the piping to a median value of the dynamic range. Piping deterioration diagnostic device.

2. a storage unit for storing characteristic information of a normal characteristic indicating a relationship between the flow rate and the vibration value before the piping is deteriorated, The diagnosis unit, in the diagnosis, If the vibration value is less than the normal characteristic, corrosion of the inner surface of the pipe is identified as a cause of deterioration of the pipe; If the vibration value is greater than the normal characteristic, the deposition of scale on the inner surface of the pipe is identified as a cause of deterioration of the pipe. The pipe deterioration diagnostic device according to claim 1 .

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