WO2016199872A1

WO2016199872A1 - Corrosion control system and corrosion control method

Info

Publication number: WO2016199872A1
Application number: PCT/JP2016/067289
Authority: WO
Inventors: 和紀宮澤; 暁之加藤; 航平齋藤; 慎也三戸; 徹也石川
Original assignee: 横河電機株式会社
Priority date: 2015-06-12
Filing date: 2016-06-09
Publication date: 2016-12-15

Abstract

The present invention enables continuous measurement and control of the shape, size, and position of a portion reduced in thickness by corrosion or the like of a metal facility. Provided is a corrosion control system (10) provided with: an electric current supply device (121) that supplies an electric current to an electrode installed on a metal facility to be monitored or to a magnetic field generating wire (112) installed in the vicinity of the metal facility; a magnetic field measuring device (125) that measures a magnetic field distribution over a surface of the metal facility; and a measurement and control device (210) that calculates the shape, size, and position of a portion reduced in thickness by corrosion or the like of the metal facility on the basis of a result of a measurement by the magnetic field measuring device (125), and generates a three-dimensional shape corresponding to the metal facility after the thickness reduction.

Description

Corrosion management system and corrosion management method

The present invention relates to a corrosion management system and a corrosion management method for performing corrosion management of metal equipment such as metal piping.

In oil and petrochemical plants, etc., if corrosion, especially local corrosion, occurs in equipment such as metal pipes, reactors, distillation towers, etc., this results in thinning of the equipment, resulting in leakage and reduced production efficiency. There is a risk of doing so. For this reason, a technology for detecting, measuring, and managing thinning caused by locally generated corrosion, etc. is desired for facilities such as metal pipes and huge reactors spread throughout the plant. Yes.

A corrosion management system has been proposed as a technique for detecting, measuring and managing the thinning caused by locally generated corrosion. The corrosion management system includes, for example, a corrosion inspection device that detects occurrence of thinning caused by corrosion and the like, and a corrosion inspection management device that manages inspection results.

As the corrosion inspection apparatus, an eddy current flaw detection apparatus, an X-ray inspection apparatus, a guide wave inspection apparatus and the like are used in addition to the most common ultrasonic thickness gauge. For example, the corrosion inspection management device has a function of acquiring measurement results from the corrosion inspection device and displaying the measurement results at measurement points.

In the device used as a corrosion inspection device, the ultrasonic thickness gauge is a device that measures the wall thickness from the speed and arrival time of ultrasonic waves propagating in the metal using an ultrasonic transmission element and a reception element. In principle, the measurement is made at one point on the surface.

An eddy current flaw detector is a device that detects a flaw on a metal surface by applying a high-frequency AC magnetic field to a piping surface or the like with a coil or the like and measuring a magnetic field generated by a current generated by the AC magnetic field.

The X-ray inspection device is a device that uses a powerful X-ray source that penetrates metal to image the inside of piping and the like based on the X-ray principle, and reads the presence or absence of thinning or deterioration from the output image.

The guide wave inspection device is a device mainly used for piping. It is a device that detects the size of the missing section and the position of the pipe lock due to thinning etc. by generating elastic waves of a special mode called guide waves in the pipe and measuring the guide wave reflected by thinning etc. .

Japanese Unexamined Patent Publication No. 2007-327924 Japanese Unexamined Patent Publication No. 2008-175638

In order to detect, measure, and manage the thinning caused by local corrosion, etc. occurring in equipment in oil and petrochemical plants, etc., a corrosion inspection device that can continuously inspect with high surface resolution and the corrosion inspection device A corrosion inspection management device that can grasp the shape, size, and position of the thinning from the obtained inspection results and map it to the three-dimensional shape of the facility is essential.

This is because the magnitude of local corrosion is extremely small with respect to equipment used in a plant or the like, and in order to detect local corrosion, it is necessary to inspect the entire equipment surface with a high surface resolution sensor. By continuously inspecting the thinning, the change in shape and size of the thinning obtained from the inspection results can be obtained over time, and the progress of corrosion can be predicted from the change in shape and size of the thinning over time. Because it becomes.

In addition, the shape and size of thinning, the position, and mapping them to the three-dimensional shape of the equipment and visualizing them are useful information for analyzing the corrosion mechanism important in corrosion management. In addition, when conducting maintenance activities for thinning caused by corrosion, etc., workers can accurately grasp the target equipment and position from the information visualized by mapping to the three-dimensional shape of the equipment. Can be made.

However, the most common ultrasonic thickness gauge as a corrosion inspection device is a point measurement, so in order to obtain the shape, size, and position of thinning caused by local corrosion with high surface resolution, it is enormous. The quantity must be measured. Therefore, it is difficult to inspect the entire surface of the monitoring target equipment with high surface resolution. Furthermore, since the measurement value of the ultrasonic thickness gage generally depends on the skill of the inspector, it is difficult to continuously measure with high reproducibility.

Also, since the eddy current flaw detector uses an electromagnetic wave with a high frequency, attenuation due to the skin effect is large, and the measurement range in the thickness direction is limited. For this reason, it is difficult to convert to a wall thickness, and it is not suitable for obtaining the shape, size, and position of the thinning caused by local corrosion. Furthermore, since a coil is required to generate eddy current inside and outside the facility, it is difficult to form an array. Therefore, it is difficult to inspect the entire equipment surface with high surface resolution.

The X-ray inspection apparatus can capture piping and the like with high surface resolution, but the output result depends on the imaging direction. For this reason, in order to grasp the shape, size, and position of the thinning caused by local corrosion of the entire piping and the like in three dimensions, a great deal of imaging and image composition are required. In addition, since the X-ray inspection apparatus requires management of the X-ray source, the introduction barrier is high and continuous measurement cannot be performed.

Guide wave inspection equipment requires very large electric power to generate a guide wave, so it is difficult to use it during operation in the explosion-proof area of the plant. Gas detection by is essential. Further, specialized knowledge is required for reading the inspection results, and the output is basically the cross-sectional defect rate, and the shape, size and position of the thinning caused by local corrosion cannot be obtained directly.

Many of the facilities such as piping used in the petroleum and petrochemical industries are located in high places and are equipped with heat insulating materials from the viewpoint of energy efficiency. The inspection device described above is premised on the operation of the person in charge of the inspection. Therefore, when performing inspection, there are many incidental works such as installation and dismantling of scaffolding for access by the inspector, and removal of insulation. Man-hours and costs are spent. For this reason, corrosion inspections of petroleum and petrochemical facilities can only be performed at least once a year, and correlation with the operation that is important in analyzing the corrosion mechanism and the occurrence of local corrosion. And can't know the process of growth. It is also difficult to predict the degree of progress of corrosion.

On the other hand, the conventional corrosion inspection management apparatus generally acquires the inspection result of the corrosion inspection apparatus through a portable storage device or is input manually. For this reason, a lot of man-hours are required for data input work. In addition, in order to analyze the corrosion mechanism from the collected data, knowledge of a corrosion specialist is required.

The present invention has been made in view of such a situation, and an object thereof is to enable continuous measurement and management of the shape, size, and position of thinning caused by local corrosion of a metal facility. .

In order to solve the above-described problem, a corrosion management system according to a first aspect of the present invention includes a magnetic field measurement device including a magnetic field sensor array that measures a magnetic field distribution on the surface of a metal facility to be monitored, and a measurement result of the magnetic field measurement device. A measurement management device that calculates the shape, size, and position of the thinning in the metal facility, and generates a three-dimensional shape corresponding to the metal facility from the shape, size, and position of the thinning. It is characterized by providing.
Here, you may further provide the electric current application apparatus which applies an electric current to the electrode installed in the said metal equipment, or the electric wire for magnetic field installation installed in the vicinity of the said metal equipment.
In addition, the measurement management device can acquire the measurement result of the magnetic field measurement device using wireless communication.
In addition, the measurement management device calculates the shape, size, and position of the metal equipment thinning based on the difference between the measurement result obtained when the metal equipment is not thinned and the actual measurement result. can do.
The current application device and the magnetic field measurement device may be independent devices.
Further, the measurement management device may correct the measurement result of the magnetic field measurement device based on the positions of the magnetic field sensor and the metal equipment constituting the magnetic field sensor array.
At this time, the measurement management device calculates a position of the magnetic field sensor and the metal facility based on the magnetic flux density obtained by an alternating current of a different frequency applied to the metal facility for a certain magnetic field sensor. Can do.
Alternatively, the measurement management device may use the magnetic field sensor based on the magnetic flux density measured for a certain magnetic field sensor and the magnetic flux density measured by the auxiliary magnetic field sensor disposed on the extension of the magnetic field sensor from the metal facility. And the position of the metal facility can be calculated.
In order to solve the above-described problem, the corrosion management method according to the second aspect of the present invention applies an electric current to an electrode installed in a monitored metal facility or a magnetic field generating wire installed in the vicinity of the metal facility. Based on the measurement result of the current application step, the magnetic field measurement step for measuring the magnetic field distribution on the surface of the metal facility, and the measurement result of the magnetic field measurement step, the shape, size, and position of the thinning of the metal facility are calculated, and the decrease A measurement management step of generating a three-dimensional shape corresponding to the metal equipment from the shape, size, and position of the meat.

According to the present invention, the shape, size, and position of thinning caused by local corrosion of a metal facility can be measured and managed, and visualized in a state mapped to the three-dimensional shape of the facility so that it can be continuously performed. Become.

It is a block diagram which shows the structure of the corrosion management system which concerns on this embodiment. It is a figure explaining the 1st principle of grasping | ascertaining a thinning state. It is a figure explaining the 2nd principle of a thinning state grasp. It is a block diagram which shows the structural example of an electric current application apparatus. It is a block diagram which shows the structural example of a magnetic field measuring device. It is a block diagram which shows the structural example of a measurement management apparatus. It is a flowchart explaining the preparation phase prior to actual operation. It is a flowchart explaining the outline | summary of the operation | movement at the time of operation | use of a corrosion management system. It is a flowchart explaining operation | movement of an electric current application apparatus. It is a flowchart explaining operation | movement of a magnetic field measuring apparatus. It is a flowchart explaining the noise removal 2nd method. It is a flowchart explaining operation | movement of a measurement management apparatus. It is the figure which considered piping as the graph which connected resistance in the grid | lattice form. It is a figure which shows the example of the three-dimensional mapping performed based on the effective value represented by the array format. It is a figure explaining the distance measurement method of monitoring object piping and a magnetic field sensor. It is a figure explaining the distance measurement method of monitoring object piping and a magnetic field sensor.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a corrosion management system 10 according to the present embodiment. The corrosion management system 10 is a system that performs corrosion management of a metal pipe (referred to as a monitoring target pipe 110) laid in the plant 100. In the present embodiment, metal piping is described as an example of corrosion management. However, the corrosion management system 10 is not limited to metal piping, and for example, metal equipment such as a distillation tower and a reactor may be targeted for corrosion management. it can.

As shown in this figure, the corrosion management system 10 includes a current application device 120, a magnetic field measurement device 130, and a measurement management device 210 connected to the control network 200, which are arranged in the vicinity of the monitoring target pipe 110 of the plant 100. I have.

The current application device 120 and the magnetic field measurement device 130 have a wireless communication function. In addition, the measurement management device 210 is connected to the wireless sensor network gateway 220 via the control network 200. Accordingly, the measurement management device 210, the current application device 120, and the magnetic field measurement device 130 can perform wireless communication with each other via the wireless sensor network 280.

The wireless sensor network 280 can be an industrial wireless sensor network such as ISA100.11a or WirelessHART, or a general-purpose wireless network such as IEEE802.11 or IEEE802.15.4.

In the corrosion management system 10 of the present embodiment, the magnetic field distribution generated by the current applied by the current application device 120 is measured by the magnetic field measurement device 130, thereby grasping the thinning state of the monitoring target pipe 110. As this principle, for example, either the first principle or the second principle described below can be used. However, other principles may be applied as long as the magnetic field distribution generated by the current applied by the current application device 120 is measured by the magnetic field measurement device 130 to grasp the thinning state of the monitored pipe 110. .

FIG. 2 is a diagram for explaining the first principle. In the first principle, as shown in the drawing, the current application device 120 applies an alternating current to the metal surface of the monitoring target pipe 110 via a pair of electrodes 111 installed on the metal surface of the monitoring target pipe 110.

This current flows at a current density according to the resistance distribution of the metal surface and generates a magnetic field. At this time, if the monitored pipe 110 is thinned due to local corrosion or the like, the resistance in the vicinity thereof changes, so that the current density distribution changes and the magnetic field distribution also changes. In the first principle, the change in the magnetic field distribution is measured by the magnetic field measuring device 130 and converted into the shape and size of the thinning. Here, the intersection of the perpendicular line drawn from the sensor indicating that there is thinning to the monitoring target pipe 110 and the monitoring target pipe 110 is an approximate position of the thinning. More specifically, by analyzing including the output of the sensor in the vicinity of the sensor indicating that there is thinning, the shape, size, and position of the thinning are converted.

FIG. 3 is a diagram for explaining the second principle. The second principle can be applied when the monitoring target pipe 110 is a magnetic body. In the second principle, as shown in the figure, the current application device 120 applies an alternating current to the magnetic field generating wire 112 disposed near the metal surface of the monitoring target pipe 110 to generate a magnetic field.

This magnetic field distribution is determined by the magnetic permeability distribution around the magnetic field source. When the permeability distribution changes due to thinning caused by local corrosion or the like of the metal surface of the pipe 110 to be monitored (the “metal surface” is a concept including the inner surface of the metal pipe), the magnetic field distribution according to the change Also changes. In the second principle, the change in the magnetic field distribution is measured by the magnetic field measuring device 130 and converted into the shape and size of the thinning. Here, the intersection of the perpendicular drawn to the monitoring target pipe 110 from the sensor indicating that there is thinning and the monitoring target pipe 110 is the position of the thinning.

In general, magnetic field measurement is affected by environmental magnetic fields such as geomagnetism. For this reason, the current applied by the current application device 120 is, for example, a frequency with good signal selectivity such as a frequency away from an integer multiple of 50 Hz or 60 Hz of the commercial frequency or a frequency that is a prime number.

When the first principle is adopted, the current applying device 120 applies an alternating current to the electrode 111 provided on the surface of the monitoring target pipe 110, and when the second principle is adopted, the current applying device 120 is near the monitoring target pipe 110. An alternating current is applied to the magnetic field generating wire 112 disposed in the section to generate an alternating magnetic field. Regardless of which principle is adopted, the magnetic field measurement device 130 is disposed in the vicinity of the monitoring target pipe 110 and measures the magnetic field distribution.

FIG. 4 is a block diagram illustrating a configuration example of the current application device 120. As shown in the figure, the current application device 120 includes a calculation unit 121, a signal generation unit 122, a current control unit 123, a storage unit 124, a magnetic field measurement device synchronization unit 125, and a wireless communication unit 126.

The calculation unit 121 performs setting processing of the current value, frequency, and the like of the applied current based on the setting information sent from the measurement management device 210. The signal generation unit 122 generates a current waveform to be applied according to the setting of the calculation unit 121. The current control unit 123 controls the applied current according to the current waveform generated by the signal generation unit 122. The storage unit 124 stores setting information such as a current setting value. The magnetic field measurement device synchronization unit 125 performs a synchronization process with the magnetic field measurement device 130. The wireless communication unit 126 performs connection processing to the wireless sensor network 280.

FIG. 5 is a block diagram illustrating a configuration example of the magnetic field measuring apparatus 130. As shown in the figure, the magnetic field measurement device 130 includes a magnetic field sensor array 131, a calculation unit 132, a sensor switching unit 133, a signal conversion unit 134, a storage unit 135, a current application device synchronization unit 136, and a wireless communication unit 137. Yes.

The magnetic field sensor array 131 is configured by arraying magnetic field sensors, and is attached to the monitoring target pipe 110 as shown in the figure. Thereby, the magnetic field distribution on the surface of the monitoring target pipe 110 can be obtained. Since the magnetic field sensor is a small sensor with low power consumption, it can be mounted at a high density on a large area. Therefore, the magnetic field distribution can be measured with high surface resolution.

The magnetic field sensor array 131 is always attached to the monitoring target pipe 110. Thereby, the effort which attaches a magnetic field sensor to the monitoring object piping 110 for every measurement can be saved, and it can measure continuously.

The sensor switching unit 133 switches the magnetic field sensor from which the measurement value is to be acquired from the magnetic field sensors constituting the magnetic field sensor array 131. That is, in the present embodiment, the measurement values are sequentially acquired from the magnetic field sensors. There are two methods for obtaining measurement values: a method for sequentially obtaining measurement values from each magnetic field sensor as in the present embodiment, and a method for obtaining measurement values all at once. Since the circuit component cost can be reduced, the present embodiment has shown a method for sequentially obtaining measured values. Of course, in order to shorten the measurement time, the measurement values may be acquired from the magnetic field sensors all at once.

The signal converter 134 converts the measurement value into a digital signal. The storage unit 135 stores measurement values converted into digital signals, setting information for measurement, and the like. The calculation unit 132 performs noise removal of the measurement value, conversion processing to an effective value, processing of setting information, and the like. A specific noise removal method will be described later. The current application device synchronization unit 136 performs a synchronization process with the current application device 120. The wireless communication unit 137 performs connection processing to the wireless sensor network 280.

With this configuration, the magnetic field measurement device 130 measures the alternating magnetic field generated by the alternating current applied by the current application device 120 with the magnetic field sensor array 131. Then, a noise removal process described later is performed on the measurement result, and then a conversion process to an effective value is performed. For example, the magnetic field measurement device 130 transmits an array of effective values corresponding to the arrayed magnetic field sensors to the measurement management device 210 via the wireless sensor network 280 as a measurement result.

In the present embodiment, the current application device 120 and the magnetic field measurement device 130 are separated to be independent devices. The first reason is that it is assumed to operate in an explosion-proof area such as the petroleum / petrochemical industry. The current application device 120 needs to handle a larger amount of electric power than the magnetic field measurement device 130, and by separating the device, the circuit configuration can be simplified, and the circuit to be considered in the event of a failure can be limited. It becomes like this.

The second reason is the difference in coverage. In the first principle of applying a current to the monitoring target pipe 110, the current application device 120 can basically cover the region between the electrodes 111 installed. Further, according to the second principle, the range in which the magnetic field generating wires 112 are arranged can be covered, and each relatively large area can be easily covered.

On the other hand, since the magnetic field measuring device 130 measures the magnetic field in the range covered by the arrayed magnetic field sensors, it is necessary to increase the number of magnetic field sensors in the magnetic field sensor array 131 in order to expand the measurement region. Is not easy.

Therefore, by separating the devices and operating one current application device 120 and a plurality of magnetic field measurement devices 130, the measurement region can be easily expanded without increasing the current application devices 120. Of course, a device in which the current application device 120 and the magnetic field measurement device 130 are integrated may be used to reduce the housing cost and space.

When measuring a magnetic field, it is necessary that the current application device 120 and the magnetic field measurement device 130 operate in synchronization so that a current is applied at the timing of measuring the magnetic field. As a synchronization method, since the electric circuit is separated, a method of triggering by communication using light such as infrared rays or a synchronization method via the wireless sensor network 280 can be considered. In order to perform these processes, the current application device 120 includes a magnetic field measurement device synchronization unit 125, and the magnetic field measurement device 130 includes a current application device synchronization unit 136.

Specifically, a method is conceivable in which one is the master and the other is the slave, the start time and the operation time are set in one (for example, the magnetic field measurement device 130), and the two are mainly synchronized. In addition, after the measurement management device 210 is synchronized via the wireless sensor network 280, the current application device 120 and the magnetic field measurement device 130 are locally synchronized via the synchronization unit in order to improve power consumption efficiency. Also good. In the present embodiment, the measurement management device 210 transmits the start time and the operation time as setting information to both the current application device 120 and the magnetic field measurement device 130, respectively. For this reason, the magnetic field measurement device synchronization unit 125 and the current application device synchronization unit 136 may be omitted.

FIG. 6 is a block diagram illustrating a configuration example of the measurement management apparatus 210. As shown in the figure, the measurement management apparatus 210 includes a calculation unit 211, a communication unit 212, a storage unit 213, and an input / output unit 214.

The communication unit 212 performs communication processing via the control network 200. The storage unit 213 is a relative position between the magnetic field measurement device 130 installed in the plant 100 and the monitoring target pipe 110, various settings in the corrosion management system 10, and an array of effective values received from the magnetic field measurement device 130 via the wireless sensor network. The calculation result of the calculation unit 211 is stored.

The calculation unit 211 converts the array of effective values received from the magnetic field measurement device 130 into the shape and size of the thinning generated in the monitoring target pipe 110, and calculates the relative position between the monitoring target pipe 110 and the magnetic field sensor array 131. Based on the process of converting into a three-dimensional shape corresponding to the monitoring target pipe 110 in consideration of the thinning, and the measurement for setting the next measurement timing in the current application device 120 and the magnetic field measurement device 130 based on the thinning state Perform setting processing. The input / output unit 214 performs a process of receiving a user operation or outputting a three-dimensional shape corresponding to the monitoring target pipe 110 in consideration of the thinning that is the processing result of the calculation unit 211. Here, the measurement management device 210 and the input / output unit 214 that receives the user's operation are integrated. However, a separate input / output device may be prepared and connected using the control network 200, for example.

In the conversion process to the three-dimensional shape corresponding to the monitoring target pipe 110 in consideration of the thinning, the calculated shape and size of the thinning are mapped to the shape of the monitoring target pipe 110. In the measurement setting process, the depth in the thickness direction and the cross-sectional defect rate are calculated from the shape and size of the thinning. Then, the rate of change per unit time is calculated by comparing with the previously measured depth of thinning and the cross-sectional defect rate. Furthermore, the time margin is calculated by comparing each with the minimum allowable wall thickness and the maximum allowable shear stress, and the next measurement timing is set in the current application device 120 and the magnetic field measurement device 130 based on the smaller margin. To do.

Next, the operation of the corrosion management system 10 of this embodiment will be described. First, the preparation phase prior to actual operation will be described with reference to the flowchart of FIG. It is assumed that the three-dimensional shape of the facility has been input in advance from laser ranging technology, 3D-CAD data of the facility, or the like.

In the preparation phase, the magnetic field sensor array 131 is installed in the monitoring target pipe 110, the electrode 111 is installed (first principle), or the magnetic field generating wire 112 is installed in the vicinity (second principle), and the current application device 120 is connected (S101).

Then, the relative positional relationship between each magnetic field sensor of the installed magnetic field sensor array 131, the electrode 111 or the magnetic field generating wire 112, and the monitoring target pipe 110 is measured and recorded in the storage unit 213 of the measurement management device 210 (S102).

Next, an outline of the operation during the operation of the corrosion management system 10 will be described with reference to the flowchart of FIG. When the predetermined measurement timing comes (S201: Yes), the current application device 120 applies a current (S202), and the magnetic field measurement device 130 measures the magnetic field distribution (S203).

The calculation unit 132 of the magnetic field measuring apparatus 130 acquires the effective value after removing noise from the measured value (S204). The effective value can be represented by an array corresponding to the magnetic field sensor array 131, whereby the magnetic field distribution on the surface of the monitoring target pipe 110 can be obtained.

The effective value represented by the array is sent to the measurement management device 210, and the calculation unit 211 of the measurement management device 210 converts it into the shape and size of the wall thickness or thickness reduction (S205). Then, the next measurement timing is set based on the change in the shape and size of the thinning (S206).

Further, the calculation unit 211 performs three-dimensional mapping of the shape and size of the thinning to the monitoring target pipe 110 based on the position information of the thinning (S207). The shape and size of the thinning, the position, and the three-dimensional mapping result are recorded in the storage unit 213 and output to a display screen or the like as necessary (S208).

Next, the specific operation of each device will be described. First, the operation of the current application device 120 will be described with reference to the flowchart of FIG. When the current application device 120 is activated, the wireless communication unit 126 requests setting information from the measurement management device 210 via the wireless sensor network 280 (S301).

As a response, setting information is received from the measurement management device 210 (S302) and recorded in the storage unit 124 (S303). The setting information includes the frequency of the alternating current to be applied, the current value, the application start time (cycle), the current application duration, and the like.

When the current application start time indicated by the setting information is reached (S304), current application is started (S305). At this time, you may make it notify the measurement management apparatus 210 that the electric current application was started.

When the current application duration indicated by the setting information has elapsed, the current application is terminated (S306). At this time, the measurement management apparatus 210 may be notified that the current application has been completed.

The current application device 120 further receives setting information related to the next measurement timing from the measurement management device 210 (S307), and waits for the next start time (S304). However, if the setting information is a stop instruction (S308: Yes), it stops.

Next, the operation of the magnetic field measurement apparatus 130 will be described with reference to the flowchart of FIG. When the magnetic field measurement device 130 is activated, the wireless communication unit 137 requests setting information from the measurement management device 210 via the wireless sensor network 280 (S401).

As the response, setting information is received from the measurement management device 210 (S402) and recorded in the storage unit 135 (S403). The setting information includes the measurement start time (cycle), the measurement time per sensor, the frequency of the alternating current applied by the current application device 120, and the like.

When the measurement start time indicated by the setting information is reached (S404), the sensor for measurement is switched (S405), and the magnetic field is measured (S406). At this time, you may make it notify the measurement management apparatus 210 that magnetic field measurement was started.

When the measurement time per sensor indicated by the setting information is measured, the measurement by the sensor is terminated, and the calculation unit 132 performs noise removal and effective value calculation processing (S407). If there is an unmeasured sensor in this process (S408: No), the sensor is switched (S405), and the measurement process is repeated.

When measurement with all sensors is completed (S408: Yes), the effective value is transmitted to the measurement management device 210 in an array format corresponding to the magnetic field sensor array 131 (S409).

The magnetic field measurement device 130 further receives setting information regarding the next measurement timing from the measurement management device 210 (S410), and waits for the next start time (S404). However, if the setting information is a stop instruction (S411: Yes), it stops.

Here, the noise removal process performed by the calculation unit 132 of the magnetic field measurement apparatus 130 in (S407) will be described. Since the AC magnetic field signal measured by the magnetic field measurement device 130 generally includes noise, it is necessary to obtain an effective value after removing the noise. As the noise removal method, the following four methods are conceivable.

First method for noise removal: This is a method in which the measured AC signal is converted into a frequency space by discrete Fourier transform or Z transform, and the frequency applied by the current application device 120 is cut out.

Second method of noise removal: The measured AC signal is converted into a frequency space by discrete Fourier transform or Z transform, and smoothing is performed to cancel higher-order noise, and regression is performed according to [Equation 1]. k ₀ is a method of extracting only. Since this method uses the instantaneous value of the signal sequence from which noise is to be removed, it is not necessary to store the signal in the memory, and the amount of RAM used in the storage unit 135 can be reduced.

More specifically, the second method for removing noise is an improvement of the first method for removing noise using discrete Fourier transform so as to meet the object of the present invention. The points of improvement are the following two points.

・ Frequency resolution is good.

・ Only the specified frequency components can be extracted, and no information about other frequencies can be obtained.

In the first method of noise removal, in order to increase the resolution of the cut-out frequency, it is necessary to lengthen the measurement time. However, in the corrosion management system 10, from the viewpoint of power consumption of the current application device 120 and the magnetic field measurement device 130. It is not preferable to lengthen the measurement time. Conversely, it is only necessary to calculate a specific frequency component, and it is not necessary to calculate other frequency components. The second noise removal method is an improvement of the first noise removal method so that the frequency resolution and the measurement time are compatible.

The principle of the second noise removal method will be described. A signal f (t) having a frequency component only in the vicinity of the angular frequency ω ₀ can be described as [Equation 2]. However, it is assumed that ω _i ≈ω ₀ .

At this time, the value to be obtained is the amplitude w ₀ corresponding to the angular frequency ω ₀ . The Fourier integral in the interval 0 ≦ t ≦ T of the signal f (t) can be calculated by [Equation 3].

F [f] (ω ₀ ) converges to ω ₀ in the limit of T → ∞. The first method for removing noise is a method for calculating the integral value. However, if we note that the above equation can be expanded to [Equation 4],

With the following two procedures, F [f] (ω ₀ ) can be converged to ω ₀ without taking the limit of T → ∞.

・ Cancel the vibration term by averaging.

· Regression equation and regression using [Equation 1], taking out only the parameter k _0.

FIG. 11 is a flowchart of this procedure. That is, the digital value of the magnetic field measurement result is acquired (S501), and Fourier integration is performed (S502). Then, smoothing is performed (S503), a regression calculation is performed (S504), and a regression result is output (S505). Note that if the precondition ω _i ≈ω ₀ is not satisfied, it means that the component corresponding to the angular frequency ω ₀ is equal to 0, so that ω ₀ = 0 without performing smoothing or regression. Is obtained.

3rd method for noise removal: Since the main component of noise is noise generated by the circuit of the magnetic field measuring apparatus 130, it is assumed that the noise is a normal distribution and a Kalman filter is applied.

Fourth method of noise removal: Since the main component of noise is noise generated by the circuit of the magnetic field measurement device 130, it is assumed that the target system is linear and a particle filter (particle filter) is applied. .

The magnetic field measurement device 130 performs the above noise removal on the AC signal measured by each magnetic field sensor of the magnetic field sensor array 131, calculates the effective value of the AC signal, and passes the wireless sensor network 280 via the wireless sensor network 280. To the measurement management device 210. However, other noise removal methods may be employed.

Next, the operation of the measurement management apparatus 210 will be described with reference to the flowchart of FIG. When the measurement management device 210 is activated, the relative position relationship between the magnetic field generating wire 112 and the magnetic field sensor array 131 installed in the monitoring target pipe 110 or the magnetic field sensor array 131 and the shape of the monitoring target pipe 110 are set. The device arrangement information is recorded in the storage unit 213 (S601).

When a request for setting information is received from another device (S602), the setting information recorded in advance in the storage unit 213 is transmitted (S603). Specifically, when the setting information request is received from the current application device 120, the frequency of the alternating current to be applied, the current value, the application start time (cycle), the current application duration, etc. are transmitted as the setting information. When a setting information request is received from the magnetic field measurement device 130, the measurement start time (cycle), the measurement time per sensor, the frequency of the alternating current applied by the current application device 120, and the like are transmitted as setting information.

When the measurement start time indicated by the setting information is reached (S604: Yes), a start notification is received from the current application device 120 and the magnetic field measurement device 130 (S605). Further, the effective value as the measurement result is received from the magnetic field measuring apparatus 130 in an array format (S606).

The measurement management device 210 stores the effective value array received from the magnetic field measurement device 130 in the storage unit 213 as a history, and the calculation unit 211 converts the AC magnetic field effective value array into a shape and size of thinning. (S607).

Here, a method for converting the array of effective values of the alternating magnetic field into the shape and size of the thinning will be described. As a method of converting the effective value into the shape and size of the thinning, for example, the effective value of each magnetic field sensor in the magnetic field distribution as a reference such as the magnetic field measured without thinning and the simulation result, and the measured effective value And calculating the magnetic field distribution, current distribution, and resistance distribution by applying the measured effective value to the physical model and calculating the magnetic field distribution, current distribution, and resistance distribution. A method for calculating the metal thickness is considered. The conversion methods (1 to 4) corresponding to the first principle and the conversion methods (5 to 8) corresponding to the second principle are shown below.

Conversion method 1: For example, when a pipe is newly installed, an AC current is applied from the current application device 120 without thinning, and the effective value of the magnetic field distribution of the AC magnetic field around the surface is measured by the magnetic field measurement device 130. Then, the data is transmitted to the measurement management apparatus 210 via the wireless sensor network 280 and stored in the storage unit 213 of the measurement management apparatus 210.

Next, the effective value of the magnetic field distribution of the alternating magnetic field around the surface of the same pipe after a certain period of time is similarly measured and transmitted to the measurement management device 210. The measurement management device 210 calculates the difference between the newly measured effective value and the reference effective value stored in the storage unit 213, and the shape and material of the piping stored in the storage unit 213, the current application device 120, and the magnetic field The relative position between the measuring device 130 and the pipe is acquired, and the difference calculation result of the effective value and the corrosion generated in the pipe are fitted to the difference result of the effective value using the semi-elliptical sphere as a model. The most suitable result is estimated as the size and position of the thinning, and the shape and size of the thinning mapped to the three-dimensional shape of the equipment together with the shape of the pipe stored in the storage unit 213 of the measurement management device 210, Calculate the position.

In addition, when the piping is a relatively simple topology and the curvature is low, fitting may be performed assuming that the piping is a flat surface. In order to obtain a three-dimensional shape of local corrosion, the unevenness of the plane due to fitting may be calculated and mapped to the shape stored in the storage unit 213.

Conversion method 2: This is a method according to the conversion method 1, but it is a method for obtaining the effective value of the magnetic field distribution of the alternating magnetic field around the reference pipe surface by magnetic field simulation. Further, in order to correct an error between the simulation result and the actual magnetic field distribution, a certain coefficient is applied to the simulation result to obtain a reference effective value.

Conversion method 3: This is a method according to conversion method 2, but the thickness distribution in the standard state is measured with another device such as an ultrasonic thickness gauge, and a simulation is performed based on the thickness distribution. This is a method in which the result is the effective value of the magnetic field distribution of the alternating magnetic field around the pipe surface as a reference.

Conversion method 4: This is a method according to the conversion method 1, but from the effective value of the magnetic field distribution of the alternating magnetic field measured by the magnetic field measurement device 130 at an arbitrary time stored in the storage unit 213 of the measurement management device 210, the resistance distribution Is estimated. The constraint conditions for estimating the resistance distribution are the measured effective value of the magnetic field, the position of the electrode on the pipe surface, the pipe specifications (for example, material, outer diameter, wall thickness), and applied current amount. In general, since the resistance distribution estimation problem is not a good setting problem, the magnitude of the current distribution or resistance distribution is used as a normalization term.

Specifically, the piping is regarded as a graph in which resistances as shown in FIG. Then, the current flowing through each resistor is estimated from the measured magnetic field, and the resistance value (metal thinning rate) is estimated from the current flowing through each resistor. The current flowing in the pipe is dominant in the direction from the one electrode to the other electrode (left and right direction in the figure), and almost no current flows in the direction perpendicular to it (up and down direction in the figure).

Therefore, the piping can be regarded approximately as a graph as shown in FIG. Compared with the graph shown in FIG. 13A, the graph shown in FIG. 13B has the advantage that the number of currents to be calculated is halved and the calculation time can be greatly shortened.

Conversion method 5: When the pipe 110 to be monitored is a magnetic metal, for example, when a pipe is newly installed, an AC current is applied from the current application device 120 without thinning, and the magnetic field distribution of the AC magnetic field around the surface is changed. The effective value is measured by the magnetic field measurement device 130. Then, the data is transmitted to the measurement management apparatus 210 via the wireless sensor network 280 and stored in the storage unit 213 of the measurement management apparatus 210.

Next, the effective value of the magnetic field distribution of the alternating magnetic field around the surface of the same pipe after a certain period of time is similarly measured and transmitted to the measurement management device 210. The measurement management device 210 calculates the difference between the newly measured effective value and the reference effective value stored in the storage unit 213, and the shape and material of the piping stored in the storage unit 213, the current application device 120, and the magnetic field The relative position between the measuring device 130 and the pipe is acquired, and the difference calculation result of the effective value and the corrosion generated in the pipe are fitted to the difference result of the effective value using the semi-elliptical sphere as a model. Estimate the size and position of the thinning for the most suitable result, and the shape, size and position of the thinning mapped to the three-dimensional shape of the equipment together with the shape of the piping stored in the storage unit 213 of the measurement management device 210 Calculate

Conversion method 6: This is a method according to the conversion method 5, but it is a method of acquiring the effective value of the magnetic field distribution of the alternating magnetic field around the reference pipe surface by magnetic field simulation. Further, in order to correct an error between the simulation result and the actual magnetic field distribution, a certain coefficient is applied to the simulation result to obtain a reference effective value.

Conversion method 7: This is a method according to conversion method 2, but the thickness distribution in the standard state is measured with another device such as an ultrasonic thickness gauge, and a simulation is performed based on the thickness distribution. This is a method in which the result is the effective value of the magnetic field distribution of the alternating magnetic field around the pipe surface as a reference.

Conversion method 8: A method according to the conversion method 4, but the resistance distribution is calculated from the effective value of the magnetic field distribution of the alternating magnetic field measured by the magnetic field measurement device 130 at an arbitrary time stored in the storage unit 213 of the measurement management device 210. From the difference in magnetic permeability between the magnetic metal and the atmosphere such as air or water and the estimated value of the magnetic field distribution, the inverse problem of estimating the thinning of the pipe made of the magnetic metal is solved. The constraint conditions at this time are the effective value of the measured magnetic field, the position of the electrode on the pipe surface, the specifications of the pipe (for example, material, outer diameter, thickness), and the amount of applied current. In general, since the resistance distribution estimation problem is not a good setting problem, the magnitude of the current distribution or resistance distribution is used as a normalization term.

In the corrosion management system 10 of the present embodiment, the magnetic field sensor array of the monitoring target pipe 110 and the magnetic field measuring device 130 at the time of installation or detachment due to the restriction of the above method for converting the measured magnetic field distribution into the shape and size of the thinning. 131, it is necessary to manage the positions of the electrodes 111 and the magnetic field generating wires 112 of the current application device 120 and to manage the relative positions. This is because the magnetic field changes in proportion to the distance from the source to the measurement point, and this appears as an error when converted. The situation in which the magnetic sensor array 131 is attached and detached includes the case where the monitoring target pipe 110 in which the magnetic field sensor array 131 is installed is inspected by another means (for example, an ultrasonic thickness gauge), or the magnetic field sensor array 131 is There may be a situation where a failure occurs and replacement is performed.

As in conversion method 1 and conversion method 5, the AC magnetic field around the surface of the metal pipe is measured with no thinning on the surface of the metal pipe (herein referred to as initial measurement), and the difference from the state with the thinning In the method for obtaining the shape and size of the thinning from the above, it is necessary to install or remove the magnetic field sensor array 131, the electrode 111 of the current application device 120, or the magnetic field generating wire 112 without error from the position at the time of initial measurement. As a method of satisfying such a requirement, there is a method of attaching a reference jig to the surface of a metal pipe during initial measurement. Further, when the electrode 111 and the magnetic field generating wire 112 are left on or near the surface of the metal equipment, there is a method of measuring the magnetic field by the magnetic field measuring device 130 using these and correcting the position from the information.

In the case of conversion method 2 and conversion method 6, the simulation result is used instead of the initial measurement result. For this reason, management of the relative position of the simulation model and the magnetic field sensor array 131 actually installed on the surface of the metal pipe, the electrode 111 of the current application device 120, or the magnetic field generating wire 112 is required.

In conversion methods 1, 2, 3, 5, 6, and 7, after attaching the magnetic field sensor array 131 to the pipe and performing the measurement, a detailed thickness inspection is performed (for example, by an ultrasonic thickness system), and then the magnetic field is continued. A situation where measurement is performed by the sensor array 131 is conceivable. In such a case, a conversion result with higher accuracy can be obtained by making the corrosion model for conversion not the semi-elliptical sphere but the shape of thinning obtained by the detailed inspection.

As a method for performing this management, for example, the relative positions of the metal pipe surface, the magnetic field sensor array 131, the electrode 111, or the magnetic field generating wire 112 are first modeled, and after simulation, these are adapted to the model. A method of installation is conceivable.

Alternatively, a method may be considered in which the magnetic field sensor array 131, the electrode 111, or the magnetic field generating wire 112 is first installed, the positions thereof are measured, a simulation model is created, and the simulation is performed. In these methods, the surface of the metal pipe is treated as having no thinning.

In the case of the conversion method 3 and the conversion method 7, although it is based on the method using the said simulation, the thickness of the metal piping measured by another means (for example, ultrasonic thickness gauge) is added to the simulation model. For this reason, it is necessary to manage the position measured by another means as the position on the model.

In the conversion method 4 and the conversion method 8, since the initial measurement state is not required, it is not necessary to manage the relative position error from the initial state as described above. However, in order to solve the inverse problem of estimating the thickness of the metal pipe from the magnetic field distribution obtained by modeling the surface of the metal pipe, it is necessary to manage the relative position of these when installed as in the simulation. is there.

Returning to the description of FIG. 12, the calculation unit 211 of the measurement management device 210 converts the effective value of the array format into the shape and size of the thinning (S607), based on the change in the shape and size of the thinning, and the like. The next measurement timing is set (S608). Specifically, the depth in the thickness direction and the cross-sectional defect rate are calculated from the shape and size of the thinning. Then, the rate of change per unit time is calculated by comparing with the previously measured depth of thinning and the cross-sectional defect rate. Furthermore, the time margin is calculated by comparing each with the minimum allowable wall thickness and the maximum allowable shear stress, and the next measurement timing is set in the current application device 120 and the magnetic field measurement device 130 based on the smaller margin. To do.

Further, the calculation unit 211 performs three-dimensional mapping to the monitoring target pipe 110 based on the effective values represented in the array format (S610). FIG. 14 shows an example of three-dimensional mapping performed based on the effective values represented in the array format.

The shape and size of the thinning, the position, and the three-dimensional mapping result are recorded in the storage unit 213 and output to a display screen or the like as necessary (S611). If there is no stop instruction (S612: No), it waits for the next start time (S604), and if there is a stop instruction (S612: Yes), it stops. At this time, stop setting information is transmitted to the current application device 120 and the magnetic field measurement device 130.

The corrosion management system 10 that is an embodiment of the present invention has been described above. According to the corrosion management system 10 of the present embodiment, for example, the following effects can be obtained.

Effect 1: Local corrosion occurring on the surface of metal equipment such as metal piping can be continuously measured and managed in three dimensions with good reproducibility.

Effect 2: Once the corrosion management system 10 is introduced, it is possible to continuously measure the thinning caused by corrosion, etc., eliminating the need for incidental work for human access to metal equipment, reducing man-hours and costs. it can. As a result, the measurement cycle can be shortened. Further, the measurement cycle can be set at an arbitrary cycle.

Effect 3: Since the current application device 120 and the magnetic field measurement device 130 are separated and compatible with the narrow-band wireless sensor network 280 corresponding to explosion prevention, the magnetic field measurement device 130 is effective after removing noise from the AC magnetic field measurement value. By outputting and transmitting the value, it becomes possible to correspond to the explosion-proof area, and it is possible to measure thinning in the explosion-proof area during operation.

Effect 4: The measurement result is transmitted and received by the wireless sensor network 280 and managed by the measurement management apparatus 210, so that it is not necessary to manage the inspection result manually.

Effect 5: The measurement result is visualized as information in which the shape and size of the thinning are mapped to the three-dimensional shape of the equipment, so that it is possible to grasp the result without special knowledge. .

Note that the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, another sensor such as a temperature sensor that measures the temperature of the surface of metal equipment such as piping and a humidity sensor may be added to the above-described corrosion management system 10. It is desirable to install a set of temperature sensors and humidity sensors near the magnetic field sensor array 131 and to install a plurality of sets of other temperature sensors and humidity sensors at other locations.

Suppose that the data of these temperature sensors and humidity sensors can be read by the measurement management device 210 of the corrosion management system 10. Specifically, a method in which the measurement management apparatus 210 directly reads through the wireless sensor network 280 and a method in which it is read indirectly through a process control system or the like are conceivable.

In this way, the measurement management device 210 has similarities between the temperature and humidity data and the history of the location where the magnetic field sensor array 131 is installed and where local corrosion actually occurs and the shape and layout of the metal equipment. In addition, local corrosion is extrapolated in a place where another set of temperature sensor / humidity sensor is installed but the magnetic field sensor array 131 is not installed.

This makes it possible to virtually manage a wider area including a position where the magnetic field sensor array 131 is not installed and local corrosion cannot be measured. In addition, although this example used the temperature sensor and the humidity sensor, you may combine with other sensors, such as a strain sensor. In addition, these data may be acquired by a facility management operator instead of a sensor and input to the measurement management apparatus 210.

Alternatively, a sensor that inputs data inside a metal facility such as a pipe to the corrosion management system 10 described above, such as a pressure sensor, a temperature sensor, a flow rate sensor, a pH sensor, an ER corrosion sensor, an electrochemical corrosion sensor, or the like. It may be added. These may be connected directly to the corrosion management system 10 via the wireless sensor network 280 or may be connected via a process control system.

The measurement management device 210 is similar to the data of sensors that measure the inside of the metal facility where the magnetic field sensor array 131 is installed and actually corroded, their history, the shape of the metal facility, the fluid in the metal facility, and the like. Based on the characteristics, local corrosion is extrapolated at other locations inside the metal facility where the magnetic field sensor array 131 is not installed.

This makes it possible to virtually manage a wider area including the position where the magnetic field sensor array 131 is not set and local corrosion cannot be measured.

By the way, local corrosion on the inner surface of metal equipment such as piping is often caused by imbalance of the environment (pressure, temperature, flow rate, etc.) of the inner surface. Therefore, the history of the sensor data of the process control system is used as an input, and fluid simulation is performed on the target equipment, so that the history of the local internal environment can be obtained and the three-dimensional shape of local corrosion can be obtained by installing the magnetic field sensor array 131. You may calculate about the location which can be measured. In this case, the same calculation is then performed elsewhere on the inner surface of the metal equipment, and the magnetic field sensor array 131 is installed based on the local history of the internal environment and the similarity of the shape of the metal equipment and the internal fluid. Extrapolate local corrosion at other locations inside the metal facility that are not.

After modeling the relationship between the local internal state obtained in this way and the extrapolated local corrosion, the process state was simulated according to the production plan to be performed in the future. Fluid simulation may be performed to create a local internal environment history in the future. In this case, the future occurrence and progress of local corrosion is extrapolated based on the history of the internal environment in the future, the similarity of the internal fluid in the shape of the metal facility, and the above-mentioned relational model.

This makes it possible to plan and set future operation plans, maintenance plans, and limit values for operation conditions more precisely.

The measurement management device 210 calculates the rate of change per unit time of local corrosion. It is also possible to calculate the thinning amount from the rate of change, obtain an approximate curve representing the relationship between the thinning amount and time, and predict the progress of local corrosion from the approximate curve.

By the way, in the corrosion management system 10 of the present embodiment, the position of the monitoring target pipe 110 and the magnetic field sensor array 131 of the magnetic field measuring device 130 at the time of installation or desorption is determined from the characteristic of the method of converting the measured magnetic field distribution into the thinning distribution. It is necessary to manage and manage the relative position. This is because the magnetic flux density changes according to the distance from the generation source to the measurement point, and this appears as an error during conversion.

Therefore, when the magnetic field sensor array 131 is attached to the monitoring target pipe 110, an attachment member corresponding to the shape of the monitoring target pipe 110 is created. For example, when the monitoring target pipe 110 is measured using a 3D scanner, an attachment member corresponding to distortion or the like of the monitoring target pipe 110 can be created.

The attachment member is preferably attached by point contact using legs or the like in order to avoid the influence on the monitoring target pipe 110 due to the contact of different metal, but the positional relationship between the magnetic field sensor and the monitoring target pipe 110 changes over a long period of time. It should be robust enough not to

However, there is a case where the relative position between the magnetic field sensor array 131 and the monitoring target pipe 110 is shifted due to the time-dependent change of the equipment, or the actually installed location is shifted from the position in the system calculation. When such a deviation occurs, the occurrence of an error can be prevented by correcting the measurement value of each magnetic field sensor constituting the magnetic field sensor array 131 according to the deviation amount.

For example, if the correction method is a deviation in the x-axis direction and the y-axis direction (a plane parallel to the surface of the monitoring target pipe 110), the deviation amount between the original magnetic field sensor position and the actual magnetic field sensor position. Accordingly, it is conceivable to correct the measurement value of each magnetic field sensor using existing techniques such as linear interpolation and bicubic interpolation using measurement values of adjacent magnetic field sensors.

In addition, if the displacement is in the z-axis direction (perpendicular to the surface of the monitored pipe 110), the measured value is inversely proportional to the square of the distance. For example, the actual magnetic field sensor is 1.5 times the original position. If it is far away, the measurement can be corrected by multiplying the measured value by a square of 1.5.

As a method of acquiring the actual position of the magnetic field sensor, a method using a 3D scanner is conceivable, but if the position is in the z-axis direction, it can also be acquired using the measured value of the magnetic field sensor.

This utilizes the skin effect that the alternating current flowing through the conductor concentrates on the conductor surface as the frequency increases and the internal current density decreases. In general, the distance at which the current density is 1 / e times the conductor surface is called the skin depth, and if the frequency is determined, the skin depth in the conductor can be specified.

Specifically, as shown in FIG. 15A, the magnetic flux density measured by the magnetic field sensor 131a when an alternating current having a frequency f1 is passed through the monitoring target pipe 110 is H1. The skin depth δ1 at this time is known. Next, as shown in FIG. 15B, the magnetic flux density measured by the magnetic field sensor 131a when an alternating current having a frequency f2 higher than the frequency f1 is passed through the monitoring target pipe 110 is set to H2. The skin depth δ2 at this time is known and becomes shallower than the skin depth δ1. Note that the frequency f1 is selected so that the skin depth is δ1 that does not reach the thinned portion even when the thinning occurs.

Here, when the distance between the monitoring target pipe 110 and the magnetic field sensor 131a is d, [Equation 5] is established. However, k is a constant determined by the applied current, the monitoring target pipe 110, and the like.

When [Equation 5] is arranged with respect to d, [Equation 6] in which k is deleted can be obtained, so that the position of the magnetic field sensor 131a in the z-axis direction with respect to the monitored pipe 110 can be obtained.

Alternatively, as shown in FIG. 16, the auxiliary magnetic field sensor 131b is disposed above the magnetic field sensor 131a, so that the position of the magnetic field sensor 131a in the z-axis direction with respect to the monitored pipe 110 can be acquired. Here, it is assumed that the distance between the magnetic field sensor 131a and the auxiliary magnetic field sensor 131b is r, and this distance r is firmly maintained by an attachment member or the like and does not change. Further, the thickness of the monitoring target pipe 110 is t.

When an alternating current is passed through the monitored pipe 110 (the skin effect need not be considered), the magnetic flux density measured by the magnetic field sensor 131a is H1, and the magnetic flux density measured by the auxiliary magnetic field sensor 131b is H2. 7] holds. However, k is a constant determined by the applied current, the monitoring target pipe 110, and the like.

By arranging [Equation 7] with respect to d, it is possible to obtain [Equation 8] in which k is deleted, and thus the position of the magnetic field sensor 131a in the z-axis direction with respect to the monitored pipe 110 can be obtained.

If the distance d obtained in this way is different from the original distance, it is possible to prevent a reduction in the accuracy of the thinning state estimation by performing correction according to the difference on the measured value.

Here, since the calculation of the relative position of the pipe and sensor and the correction coefficient are performed approximately using the concept of the current center, [Equation 5] and [Equation 7], all the correction coefficients are the square of the distance. It is in the form of inverse proportion. Without using the concept of current center, it is possible to derive a more realistic correction formula by using, for example, precise calculation of current distribution or numerical simulation.

The above description merely shows a specific preferred embodiment for the purpose of explanation and illustration of the present invention. Therefore, the present invention is not limited to the above-described embodiments, and includes many changes and modifications without departing from the essence thereof.
Note that this application is a Japanese patent application filed on June 12, 2015 (Japanese Patent Application No. 2015-119553), a Japanese patent application filed on May 11, 2016 (Japanese Patent Application No. 2016-095553), Which is incorporated by reference in its entirety. Also, all references cited herein are incorporated as a whole.

DESCRIPTION OF SYMBOLS 10 ... Corrosion management system, 100 ... Plant, 110 ... Monitoring object piping, 111 ... Electrode, 112 ... Electric field for magnetic field generation, 120 ... Current application apparatus, 121 ... Calculation part, 122 ... Signal generation part, 123 ... Current control part, DESCRIPTION OF SYMBOLS 124 ... Memory | storage part, 125 ... Magnetic field measuring device synchronization part, 126 ... Wireless communication part, 130 ... Magnetic field measuring device, 131 ... Magnetic field sensor array, 132 ... Operation part, 133 ... Sensor switching part, 134 ... Signal conversion part, 135 ... Storage unit 136 ... Current application device synchronization unit 137 ... Wireless communication unit 200 ... Control network 210 ... Measurement management device 211 ... Calculation unit 212 ... Communication unit 213 ... Storage unit 214 ... Input / output unit 220 ... Wireless sensor network gateway, 280 ... Wireless sensor network

Claims

A magnetic field measurement apparatus including a magnetic field sensor array for measuring a magnetic field distribution on a surface of a metal facility to be monitored;
Based on the measurement result of the magnetic field measurement device, the shape, size, and position of the thinning in the metal facility are calculated, and the three-dimensional shape corresponding to the metal facility is generated from the shape, size, and position of the thinning. A measurement management device,
A corrosion management system comprising:
The corrosion management system according to claim 1, wherein the measurement management device acquires a measurement result of the magnetic field measurement device using wireless communication.
The measurement management device calculates the shape, size, and position of the thinning of the metal facility based on the difference between the measurement result obtained when the metal facility has no thinning and the actual measurement result. The corrosion management system according to claim 1 or 2.
The current application device according to any one of claims 1 to 3, further comprising a current application device configured to apply a current to an electrode installed in the metal facility or a magnetic field generating wire installed in the vicinity of the metal facility. Corrosion management system.
The corrosion management system according to claim 4, wherein the current application device and the magnetic field measurement device are independent devices.
The measurement management device includes:
The corrosion management system according to claim 4 or 5, wherein the measurement result of the magnetic field measurement device is corrected based on the positions of the magnetic field sensor and the metal equipment constituting the magnetic field sensor array.
The current application device applies a current to an electrode installed in the metal facility,
The measurement management device includes:
The position of the magnetic field sensor and the metal equipment is calculated based on the magnetic flux density obtained by the alternating current of the different frequency applied to the metal equipment about a certain magnetic field sensor. Corrosion management system.
The measurement management device includes:
Based on the magnetic flux density measured for a certain magnetic field sensor and the magnetic flux density measured by the auxiliary magnetic field sensor disposed on the extension of the magnetic field sensor from the metal facility, the position of the magnetic field sensor and the metal facility is determined. The corrosion management system according to claim 6, wherein the corrosion management system is calculated.
A current application step of applying a current to an electrode installed in a metal facility to be monitored or a magnetic field generating wire installed in the vicinity of the metal facility;
A magnetic field measuring step for measuring a magnetic field distribution on the surface of the metal equipment;
Based on the measurement result of the magnetic field measurement step, the shape, size, and position of the thinning of the metal equipment are calculated, and a three-dimensional shape corresponding to the metal equipment is generated from the shape, size, and position of the thinning. A measurement management step to perform,
A corrosion management method characterized by comprising: