JP2011007294A - Valve monitoring method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine small leakage with high accuracy in regard to an opening and closing state monitoring of a valve determining and monitoring an opening and closing state of the valve by using correlativity between strain of a valve rod or the like and an opening and closing state.SOLUTION: The valve monitoring system 1 includes a valve state detection sensor 11 detecting strain caused in the valve rod 4 of a manual valve 2, and an opening and closing state determining part 21 determining the opening and closing state of the manual valve on the basis of strain information acquired by the valve state detection sensor. Furthermore, the valve monitoring system 1 includes a small leakage determining part 22 determining small leakage in a closed state on the basis of frequency information acquired by detecting an oscillation frequency of the manual valve in the closed state.

Description

  The present invention relates to a valve monitoring method and a valve monitoring system for remotely monitoring an open / close state of a valve.

  In plants such as nuclear power plants, many automatic valves and manual valves are installed in the piping system. Normally, the opening and closing of the valve in the plant is determined according to the system configuration determined by the operating state of the plant and the like. Therefore, it is necessary to remotely determine and monitor the open / close state of each valve with respect to the system configuration from a management room or the like.

  As for the remote open / close state monitoring of the valve, examples disclosed in Patent Documents 1 to 3, for example, are known. Each of these prior arts can be said to have advantages and disadvantages, but the configuration of the equipment required for monitoring the open / close state, particularly the equipment provided on the valve side, is simpler than that of the techniques of Patent Document 2 and Patent Document 3. The method based on the strain reference determination as in the example disclosed in Patent Document 1 is excellent in that it can be completed with a high degree of accuracy and the open / close state can be determined with high accuracy.

  In the strain reference determination method, the open / closed state is determined by utilizing the fact that there is basically a high correlation between the strain generated in a valve mechanical element, for example, a valve stem in accordance with the open / close operation, and the open / closed state of the valve. That is, the strain generated in the valve stem or the like is detected by a sensor, and the open / close state of the valve is determined and monitored based on the strain information obtained thereby. For this reason, as a device provided on the valve side, it is only necessary to use a strain detection sensor and its associated device, and the open / closed state can be determined using a high correlation between the strain of the valve stem and the open / closed state. Thus, it is possible to determine the open / closed state with high accuracy.

Japanese Patent Laid-Open No. 9-14498 JP 2007-32771 A JP 2008-39126 A

  As described above, the strain reference determination method is excellent for monitoring the open / close state of the valve, but is not always sufficient. As described above, in the strain reference determination method, the open / close state of the valve is determined and monitored by utilizing the fact that there is basically a high correlation between the strain of the valve stem and the open / close state. However, in the valve, erosion or the like may cause aging damage to the valve body or the valve seat, and foreign matter may be caught between the valve body and the valve seat. When such a situation occurs, particularly when a certain amount of damage has occurred over time, when the valve is closed, the correlation between the strain of the valve stem and the closed state is the extent of damage to the valve body and valve seat. Decreases accordingly. As a result, even if it is determined that the closed state is determined in the strain criterion determination, in practice, a minute gap remains between the valve body and the valve seat, thereby causing a minute leak. Can happen. In other words, in the strain criterion determination, there remains a problem of overlooking the minute leak that the incompletely closed state with the minute leak cannot be determined and may be overlooked.

  Such a problem of overlooking a minute leak in the switching state monitoring is particularly important in a valve in a nuclear power plant. That is, in the case of a nuclear power plant, most of the valves are installed in the drain line or the vent line. The drain line and the vent line are lines that discharge the fluid flowing in the pipe to the outside of the system. For this reason, if the valve is in an incompletely closed state and a slight leak occurs, the operation of the plant may be greatly affected. Therefore, when monitoring the open / close state of valves in the drain line and vent line of a nuclear power plant, it should be possible to judge minute leaks with high accuracy, thereby overlooking incompletely closed states involving minute leaks. It is strongly desired to be able to make a highly accurate open / close state determination without any interference.

  The present invention has been made in response to such a demand, and monitoring the opening / closing state of a valve by a strain criterion determination method, that is, determining the opening / closing state of a valve by utilizing the correlation between strain of the valve stem and the opening / closing state. Therefore, an object of the present invention is to make it possible to determine a minute leak with high accuracy in monitoring the open / close state of a valve to be monitored.

  In the present invention, it is possible to determine a minute leak with high accuracy, thereby enabling a highly accurate open / close state determination without overlooking an incompletely closed state involving a minute leak. Pay attention to the relationship of vibration. That is, the leak in the valve causes the valve to vibrate due to the fluid passing through a narrow gap between the valve body and the valve seat. The vibration due to the leak is a vibration having a frequency corresponding to the degree of the leak. Therefore, by detecting the frequency of the vibration of the valve in the closed state and using the frequency information obtained thereby, it is possible to determine the occurrence of a leak, and incomplete closure that may be overlooked in the strain criterion determination. It is possible to determine the occurrence with high accuracy by focusing on a minute leak that is a leak depending on the state.

  In the present invention, the above-mentioned problems are solved based on the above concept. Specifically, in a valve monitoring method that detects strain generated in a mechanical element of the valve, and determines and monitors the open / closed state of the valve based on strain information obtained thereby, the closed state The frequency of the vibration of the valve is detected, and the presence or absence of a minute leak in the closed state is monitored based on the frequency information obtained thereby.

  In the valve monitoring method as described above, it is preferable to determine that there is a minute leak when a frequency included in a reference frequency band prepared in advance is detected for the vibration of the valve. By doing so, it is possible to more effectively perform a determination focusing on a minute leak due to an incompletely closed state that may be overlooked in the strain reference determination. In other words, if the reference frequency band is the frequency band obtained by measuring the vibration of the valve in a state where an incompletely closed state that may be overlooked in the strain criterion judgment is generated on the valve to be monitored on a trial basis, Therefore, it is possible to effectively focus on a minute leak for monitoring purposes.

  Moreover, in this invention, about solving the said subject based on the above ideas, based on the strain information obtained by the valve state detection sensor which detects the distortion which has arisen in the mechanical element of a valve, and the said valve state detection sensor In the valve monitoring system provided with the open / close state determination means for determining the open / close state of the valve, the frequency of the vibration of the valve in the closed state can be detected, and the minute amount in the closed state can be detected based on the frequency information obtained thereby. It is characterized by having a minute leak judging means for judging the presence or absence of a leak.

  Further, in the present invention, for the valve monitoring system as described above, for the same reason as described above, the minute leak determination means detects a frequency included in a reference frequency band prepared in advance for the vibration of the valve. In this case, it is preferable to determine that there is a minute leak.

  Regarding the valve monitoring system as described above, with regard to the detection of the frequency of the valve vibration, a form that also serves as a valve state detection sensor for strain detection and a form that uses a sensor dedicated to detecting the valve vibration frequency are possible. However, it is preferable to use a single valve state detection sensor for strain detection and valve vibration frequency detection in that the configuration of the device provided on the valve side can be simplified. Therefore, in the present invention, the above-described valve monitoring system is preferably configured such that the frequency is detected by the valve state detection sensor.

  According to the present invention as described above, a minute leak can be determined with high accuracy in monitoring the open / close state of the valve by the strain criterion determination method.

It is a figure which shows the structure of the valve monitoring system by one Example. It is a figure which shows the example of the table of the data for valve state monitoring. It is a figure which shows the flow of a valve monitoring process. It is a figure which shows the example of the data format of valve state information. It is a figure which shows the structure of the valve monitoring system at the time of applying to an automatic valve.

  Hereinafter, modes for carrying out the present invention will be described. The valve monitoring system and the valve monitoring method according to the present invention are suitable for monitoring the open / closed state of a valve. In the following description, the manual valve is described as an example of monitoring, but the monitoring target may be an automatic valve.

  FIG. 1 schematically shows a configuration of a valve monitoring system according to an embodiment. The valve monitoring system 1 according to the present embodiment remotely targets a manual valve 2 installed in, for example, a drain line or a vent line of a piping system in a nuclear power plant. Here, there are usually a plurality of manual valves to be monitored by the valve monitoring system 1, but in FIG. 1, these manual valves are represented by the manual valve 2.

  The manual valve 2 has a handle 3 for opening / closing operation at the head. A valve stem 4 is attached to the handle 3. By rotating the handle 3 by manual operation, the valve stem 4 moves forward and backward in the state shown in the figure. A valve body (not shown) is provided at the tip of the valve stem 4 and is closed by pressing the valve body against a valve seat (not shown) in the valve box 5 by the forward movement of the valve stem 4. The valve body is opened by pulling it away from the valve seat.

  In such a manual valve 2, a certain strain is generated in the valve stem 4 in accordance with the opening / closing operation, and the strain in the valve stem 4 has a high correlation with the open / close state. The valve monitoring system 1 monitors and monitors the open / close state of the manual valve 2 based on the strain reference determination using the correlation between the strain of the valve stem 4 and the open / close state, and cannot be determined by the strain reference determination. In order to be able to monitor the incompletely closed state, which has a characteristic, the minute leak at the time of valve closing is determined by the vibration frequency reference using the correlation between the vibration caused by the leak in the manual valve 2 and the degree of the leak. And monitor. For these functions, the valve monitoring system 1 includes a valve state detection sensor 11, a data transmission system 12, a valve state monitoring device 13, and a valve state monitoring database 14.

  The valve state detection sensor 11 is composed of a sensor having a composite detection function, and is attached to the valve stem 4. The valve state detection sensor 11 detects various states of the manual valve 2 and acquires necessary valve state information. Specifically, strain information obtained by detecting the strain of the valve stem 4 (hereinafter referred to as detected strain information as appropriate) and frequency information obtained by detecting the frequency of vibration generated in the manual valve 2 (hereinafter referred to as “strain information”). (Referred to as detection frequency information as appropriate) is acquired as basic valve state information, and temperature information and radioactivity concentration information of the manual valve 2 are also acquired as additional valve state information as necessary.

  The data transmission system 12 includes a wireless communication module 15 and a repeater 16. The wireless communication module 15 receives the valve state information (strain information, frequency information, etc.) acquired by the valve state detection sensor 11 from the valve state detection sensor 11 by wired transmission, and transmits it to the repeater 16 by wireless communication. Function. Such a wireless communication module 15 is preferably attached to the manual valve 2 so as not to be directly exposed to the radiant heat from the valve box 5, and in the illustrated example, the yoke portion of the manual valve 2 is provided. 17 is attached. The repeater 16 is installed in a range where wireless communication with the wireless communication module 15 can be performed, and functions to relay data transmitted by the wireless communication module 15 and transmit the data to the valve state monitoring device 13 by wired communication. In general, a plurality of such relays 16 are provided in such a manner that, for example, a plurality of manual valves to be monitored by the valve monitoring system 1 are grouped into several groups and provided for each group.

  The valve state monitoring device 13 has a function of monitoring the opening / closing state and the minute leak as described above in the valve monitoring system 1, and for that purpose, the opening / closing state determination unit 21, the minute leak determination unit 22, and the display unit 23. As a software element.

  The open / close state determination unit 21 functions as an open / close state determination unit, and determines the open / close state of the manual valve 2 by strain reference determination. That is, the open / close state of the manual valve 2 is determined using the detected strain information. Specifically, the strain value in the detected strain information is compared with a reference strain value (closed reference strain value or open reference strain value) stored in the valve state monitoring database 14, and if both values match, it is correct. If it is judged as an open / closed state (open when it should be open and closed when it should be closed) and the two values do not match, it will be in the wrong open / close state (closed when it should be open) It is determined that it is open when it should be closed.

  The minute leak determination unit 22 functions as a minute leak determination unit, and determines the presence or absence of a minute leak when the valve is closed based on the vibration frequency. That is, the presence / absence of a minute leak when the valve is closed is determined using the detected frequency information. Specifically, the detection frequency in the detection frequency information is compared with the reference frequency band stored in the valve state monitoring database 14, and if the detection frequency is included in the reference frequency band, it is determined that there is a minute leak, and the detection frequency is If it is outside the reference frequency band, it is determined that there is no minute leak.

  The display unit 23 has a function of displaying the open / closed state, the determination result of the minute leak, and the like on the monitoring monitor in a predetermined form. Here, as the monitoring monitor, for example, a display device (not shown) for a management room provided by connecting to the valve state monitoring device 13 is used, and a field worker carries it as necessary. A display device (not shown) of a portable personal computer is also used.

  The valve state monitoring database 14 stores and manages various data related to valve state monitoring for each valve monitored by the valve monitoring system 1. The valve state monitoring related data to be stored and managed mainly includes valve state monitoring reference data, valve attribute data, valve installation location data, and monitoring history data. Each of these data is managed in a table format created for each manual valve to be monitored by the valve monitoring system 1, for example.

  FIG. 2 shows an example of a table of valve state monitoring data. In this example, the valve identification data is the valve number, the valve condition monitoring reference data is the reference strain value (closed reference strain value and the open reference strain value), the reference frequency band, and the valve attribute data is the valve manufacturer, valve model As the design temperature, design pressure, valve installation location data, building name, system name, monitoring history data, valve status detection sensor management number, valve operation history, and determination history data items are provided in the field.

  Of particular importance in the data recorded in each of these data items are the closed reference strain value, the open reference strain value, and the reference frequency band. The closed reference strain value and the open reference strain value are prepared by measuring and acquiring the strain of the valve stem 4 in the fully closed state and the fully opened state of the manual valve 2. The acquisition is performed at the time when the manual valve 2 is installed in the piping system or at an appropriate time as necessary. On the other hand, the reference frequency band is prepared by measuring and acquiring the frequency band of vibration in the manual valve 2 in a state where a micro leak that is a leak that may be overlooked in the strain reference determination is experimentally generated. . The acquisition is performed at the same time as the case of the reference strain value. In the case of the manual valve 2, as an example, the center frequency of vibration when a minute leak occurs is in the vicinity of 20 kHz, and therefore about 20 ± 10 kHz is the reference frequency band.

  Below, the valve monitoring method performed with the above valve monitoring systems 1 is demonstrated. FIG. 3 shows a flow of valve monitoring processing in the valve monitoring method. The monitoring of the open / close state of the manual valve 2 and the minute leak is performed every time the manual valve 2 is closed or opened, is regularly performed regardless of the opening / closing operation, or is performed at any time. And each process of step S1-step S9 is included as one monitoring cycle.

  First, at step S1, a monitoring request is made. The monitoring request may be automatically generated (in the case of opening / closing monitoring or periodic monitoring) or manually (in the case of occasional monitoring). In step S2, an acquisition request for valve state information is made. The valve state information acquisition request is made, for example, when the valve state monitoring device 13 sends an activation signal to the valve state detection sensor 11 and the wireless communication module 15.

  When an acquisition request for the valve state information is made, the valve state detection sensor 11 acquires the valve state information (step S3), and then the valve state detection sensor 11 uses the data transmission system 12 to acquire the acquired valve state information. In response to this, the valve state monitoring device 13 takes in the valve state information in a predetermined data format (step S4). FIG. 4 shows an example of a data format when the valve state monitoring device 13 takes in the valve state information. In this example, the table format is used, and the information items of the valve number of the monitoring target valve in the monitoring, the management number of the valve state detection sensor in the monitoring target valve, the acquisition date and time of valve state information, strain information, and frequency information are fields. It is a table provided.

  The valve state monitoring device 13 that has taken in the valve state information first collates the valve state information with the valve state monitoring reference data stored in the valve state monitoring database 14, and displays the result on the monitoring monitor by the display unit 23 ( Step S5).

  In subsequent step S6, the open / close state determination unit 21 performs open / close state determination. Specifically, it is determined whether the detected strain value in the valve state information matches the reference strain value (the closed reference strain value or the open reference strain value). If it is determined that there is a mismatch, it is determined that there is an erroneous opening / closing state. Whether the closed reference strain value or the open reference strain value is used as the reference strain value depends on whether the manual valve 2 is opened during the monitoring cycle according to the system configuration of the piping system in which the manual valve 2 is installed. It depends on whether it should be closed.

  In the open / closed state determination in step S6, there can be three determination results as a normal open state, a normal close state, and an erroneous open / close state. If it is determined to be in the normally open state, the process ends. If it is determined to be in the erroneously opened / closed state, the process proceeds to step S7 to warn about the erroneously opened / closed state, and the process is terminated. Proceed to S8.

  In step S8, the minute leak determination unit 22 performs minute leak determination. Specifically, it is determined whether or not the detected frequency in the valve state information is included in the reference frequency band. If it is determined that the detected frequency is not included, it is determined that there is no minute leak, and the process ends. If it is determined, it is determined that there is a minute leak, the process proceeds to step S9, a warning is given for the minute leak, and the process is terminated.

  Here, when an erroneous opening / closing state warning is made in step S7 or a minute leak warning is made in step S9, the field worker will take necessary measures. In other words, when an erroneous opening / closing state warning is given, the manual valve 2 is returned to the closed state or the open state, and when a minute leak warning is given, is the manual valve 2 closed until the minute leak is eliminated? Alternatively, if the minute leak is not resolved even after the closing operation, the manual valve 2 is dealt with as a failure or failure. When dealing with such a minute leak, the valve state monitoring device 13 performs a minute leak determination for dealing with the minute leak, and performs a closing operation for eliminating the minute leak while referring to the determination result. Is preferred.

  According to the valve monitoring system 1 or the valve monitoring method as described above, a minute leak can be determined and monitored with high accuracy in accordance with the opening / closing state monitoring by the strain reference determination method. As a result, in addition to being able to make a highly accurate open / close state determination without overlooking the incompletely closed state with a minute leak, it also detects a minute leak as a malfunction or failure of the valve. This makes it possible to respond quickly to valve failures and failures.

  FIG. 5 schematically shows the configuration of the valve monitoring system when applied to the automatic valve 24. In this embodiment, the valve state monitoring sensor 25 is attached to the valve rod 27 of the automatic valve 24, and can be remotely monitored from the valve state monitoring device by the wireless communication module 28 and the repeater 29. As in the first embodiment, the valve state is monitored based on the frequency information. In this embodiment, since an automatic valve is used, it is not necessary to manually open and close the valve, and remote opening and closing control can be performed. Therefore, by combining with the valve monitoring system, it is possible to perform from valve monitoring to opening / closing control without the operator going to the site.

  As mentioned above, although the form for implementing this invention was demonstrated, this is only a representative example and this invention can be implemented with various forms in the range which does not deviate from the meaning. For example, although the said form was a case where the manual valve and automatic valve in a nuclear power plant are made into the monitoring object, it is applicable also to another plant. Moreover, in the said form, it was set as the case where the distortion | strain of a valve rod was detected, However, For example, mechanical elements other than a valve rod, such as a yoke part, can also be made into a distortion | strain detection object.

DESCRIPTION OF SYMBOLS 1 Valve monitoring system 2 Manual valve 11 Valve state detection sensor 21 Opening / closing state determination part (opening / closing state determination means)
22 Minute leak judgment unit (minute leak judgment means)
24 Automatic valve

Claims (5)

In a valve monitoring method adapted to detect and monitor the open / close state of the valve based on strain information obtained by detecting strain generated in a mechanical element of the valve,
A valve monitoring method characterized in that the frequency of vibration of the valve in the closed state is detected, and the presence or absence of a minute leak in the closed state is monitored based on frequency information obtained thereby.   2. The valve monitoring method according to claim 1, wherein a minute leak is determined when a frequency included in a reference frequency band prepared in advance is detected for vibration of the valve. In a valve monitoring system comprising: a valve state detection sensor for detecting strain generated in a mechanical element of the valve; and an open / close state determination means for determining an open / close state of the valve based on strain information obtained by the valve state detection sensor ,
A valve monitoring system characterized in that it can detect the frequency of vibration of the valve in the closed state, and comprises minute leak determination means for determining the presence or absence of a minute leak in the closed state based on frequency information obtained thereby. .   4. The minute leak determining means is configured to determine that there is a minute leak when a frequency included in a reference frequency band prepared in advance is detected for vibration of the valve. The valve monitoring system described.   The valve monitoring system according to claim 3 or 4, wherein the frequency is detected by the valve state detection sensor.

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