JP2009063313A - Gas leakage monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas leakage monitoring system which enables precise detection of the change in the degree of gas leakage from gas piping, at an early stage. <P>SOLUTION: The gas leakage monitoring system S comprises a ventilation device 30 which ventilates an indoor space 10 where gas piping 21, for which an emergency measure for checking the gas leakage is taken with a fastening band 22, exists; a first gas detector 41 which is disposed in the indoor space 10; a second gas detector 42 which is disposed in an exhaust duct 32 of the ventilation device 30; and a collective device 50 which collects detection data obtained by the first and second gas detectors 41 and 42. Since the second gas detector 42 detects the concentration of gas in the exhaust duct 32 exhausting the surrounding air of an emergency measure part that contains the leakage gas, the a state in a stage prior to the indoor space 10 reaching an actually hazardous state can be precisely detected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a system for monitoring gas leakage in an indoor space where a gas distribution pipe exists.

  If a gas leak occurs in city gas piping due to corrosion, etc., emergency measures such as covering the periphery of the piping leakage with a metal fastening band or taping coating are taken, and piping is a permanent measure at a later date. Is exchanged. This first-aid step is involved because it is difficult to prepare a replacement pipe that matches the situation on site immediately after reporting a gas leak, and the gas supply for pipe replacement depends on the user's work situation, etc. This is because it cannot be stopped immediately. Therefore, for a certain period, the state where only the emergency treatment is applied to the leaked portion of the pipe continues.

  However, when the gas pressure exceeds the intermediate pressure class, it is difficult to completely stop the gas leakage only by the above-mentioned emergency treatment. In addition, it is particularly difficult to suppress leakage when there is a leakage portion in the curved portion of the pipe. Accordingly, measures are required on the assumption that a slight amount of gas leakage always occurs during the emergency treatment period.

For example, when a leaking pipe exists in an indoor space, the indoor space is constantly ventilated and the worker periodically measures the gas concentration in the indoor space with a portable gas detector. Has been taken. However, since it is often difficult to keep workers on site for 24 hours, a gas detection sensor is placed in an indoor space, and the detection data is transmitted to the monitoring center via a communication device to remotely monitor the situation of gas leakage. The method of monitoring is exclusively taken. In addition, patent documents 1-5 can be illustrated as a prior art which detects gas leakage in indoor space, for example.
Japanese Utility Model Publication No. 59-47843 JP-A-5-52720 Japanese Patent Laid-Open No. 10-311812 JP 2001-153771 A JP 2006-90891 A

  As described above, it is difficult to completely suppress the gas leakage only by applying the emergency measure, and it is also assumed that the degree of gas leakage gradually increases. However, such a change in the degree of gas leakage may not be detected quickly and accurately only by regular monitoring of workers and detection results of sensors installed in indoor spaces.

  The present invention has been made in view of the above points, and an object thereof is to provide a gas leakage monitoring system capable of accurately detecting a change in the degree of gas leakage from a gas pipe at an early stage. To do.

  The gas leakage monitoring system according to the present invention includes a ventilation means for ventilating an indoor space where a gas distribution pipe exists, a first gas detection means installed in the indoor space, and exhaust of the indoor space by the ventilation means. A second gas detection means arranged in the path, and a data collection device for collecting detection data by the first and second gas detection means are provided (claim 1).

  According to the above configuration, not only the first gas detection means is installed in the indoor space, but also the second gas detection means is arranged in the exhaust path of the indoor space. Since the second gas detection means measures the gas concentration in the air forcedly exhausted from the indoor space, when the gas leakage occurs from the pipe, the gas concentration is higher than that of the first gas detection means. Will be detected. Further, the first gas detection means hardly detects gas when ventilation of the indoor space by the ventilation means is superior to gas leakage. On the other hand, when the degree of gas leakage increases, the second gas detection means detects a dense gas concentration. When the ventilation of the indoor space by the ventilation means cannot catch up with the gas leakage, the first gas detection means also Gradually gas concentration is detected. Therefore, by utilizing such a relationship, a change in the degree of gas leakage can be accurately detected at an early stage.

  In the above configuration, it is one of preferred uses of the present invention that the ventilation means ventilates an indoor space where a gas distribution pipe subjected to an emergency measure for suppressing gas leakage is present (claim). Item 2). According to this configuration, it is possible to quickly and accurately detect a gas leak from the emergency treatment portion and a change in the degree of gas leak.

  In the above configuration, it is desirable that the ventilation means includes an exhaust duct as the exhaust path, and the second gas detection means is disposed in the exhaust duct. According to this configuration, since the second gas detection unit is disposed in a closed space called an exhaust duct, the detection sensitivity of the second gas detection unit can be increased.

  In the above-described configuration, it is desirable that the data collection device includes a storage unit that stores the detection data at a predetermined sampling period. According to this configuration, it is possible to confirm data such as changes in gas concentration after the fact.

  In the above configuration, it is preferable that the data collection device further includes an external device that is communicably connected via a communication network, and the external device is capable of acquiring detection data collected by the data collection device. (Claim 5). According to this configuration, it is possible to perform remote monitoring of gas leakage using an external device via a communication network in a remote place away from the indoor space.

  In any one of the above-described configurations, the data collection device obtains gas concentrations in the indoor space and the exhaust path based on the detection data, and compares a predetermined criterion with the gas concentration to detect a gas leak. It is desirable to include determination means for determining the state (claim 6). In this case, it is desirable that the determination means transmits an alarm signal when it is determined that the gas concentration in the indoor space and / or the exhaust path has exceeded a predetermined level. According to these configurations, it becomes possible to quickly know the gas leakage state based on the output value of the determination means or the alarm signal.

  In this case, the determination means includes the first gas concentration set as the first danger level and the second gas set as the second danger level that is higher in risk than the first danger level. Concentration is used as the determination criterion, and a first alarm signal is transmitted when the gas concentration based on the detection data of the second gas detection means exceeds the first gas concentration, and the first gas When the gas concentration based on the detection data of the detection unit exceeds the first gas concentration, a second alarm signal is transmitted, and the detection of the second gas detection unit and / or the first gas detection unit is performed. It is desirable to send a third alarm signal when the gas concentration based on the data exceeds the second gas concentration. According to this configuration, since an alarm signal is transmitted according to the stage of the danger level, the manager or the like can take an appropriate countermeasure according to the danger level.

  In the above-described configuration, it is desirable that the data collection device includes a notification unit that performs a predetermined notification operation when the warning signal is transmitted. According to this structure, the notification according to the gas leak state can be performed around the data collection device.

  According to the gas leakage monitoring system of the present invention, the first gas detection means is installed in the indoor space and the second gas detection means is arranged in the exhaust path of the indoor space. It is possible to accurately detect a change in the degree of leakage at an early stage. Therefore, it is possible to take measures against gas leakage in the indoor space at a low risk level.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing a hardware configuration of a gas leakage monitoring system S according to an embodiment of the present invention. This gas leakage monitoring system S is a system suitable for monitoring gas leakage in the piping system 20 that supplies city gas to consumers such as factories, commercial facilities, and buildings. The piping system 20 is a piping for drawing city gas from a conduit buried in a public road or the like into the premises of a business operator. Here, the piping system 20 existing inside the building (indoor space 10). Is shown.

  The piping 21 constituting the piping system 20 is generally a robust piping made of a metal material, but may deteriorate due to aging, corrosion, etc., and gas leakage may occur. FIG. 1 shows an example in which gas leakage occurs in the pipe 21 and the periphery of the leakage portion is covered with a metal fastening band 22. As described above, the covering with the fastening band 22 is an emergency measure, and the pipe 21 in which leakage occurs later is replaced with a new pipe.

  The gas leakage monitoring system S of this embodiment is for monitoring gas leakage in the indoor space 10 after this emergency treatment until it is replaced with a new pipe. When the pipe 21 is a pipe having a high gas pressure, it is difficult to completely prevent gas leakage even if an emergency treatment is performed with the fastening band 22. Therefore, the gas leakage monitoring system S is a monitoring system for the purpose of grasping a change in the degree of gas leakage on the assumption that gas leakage occurs.

  The gas leakage monitoring system S includes a ventilation device 30 (ventilation means) for ventilating the indoor space 10, a first gas detector 41 (first gas detection means) installed at an appropriate location in the indoor space 10, and the ventilation device 30. The second gas detector 42 (second gas detection means) disposed in the exhaust path of the indoor space 10 and the collective device 50 that collects detection data from the first gas detector 41 and the second gas detector 42 ( Data aggregation device) and an external device 60 communicably connected to the aggregation device 50 via a communication network.

  The ventilation device 30 includes a ventilation fan 31 and an exhaust duct 32. The ventilation fan 31 has a function of intake and exhaust, and is preferably arranged so that the intake side thereof is directed to the emergency treatment portion by the fastening band 22 of the pipe 21. The exhaust duct 32 is a bellows-like cylinder that forms the exhaust path of the indoor space 10. The inlet side 321 of the exhaust duct 32 is connected to the exhaust side of the ventilation fan 31, and the outlet side 322 is disposed outside the indoor space 10. Therefore, the air in the indoor space 10 sucked by the ventilation fan 31 is exhausted to the outside through the exhaust duct 32.

  The first gas detector 41 detects the gas concentration in the indoor space 10 and can employ various sensing methods such as an infrared method and a semiconductor method. FIG. 1 shows an example in which the first gas detector 41 is attached to an arm supported by a camera tripod 411 so that its installation position can be freely adjusted.

  The second gas detector 42 detects the gas concentration in the air passing through the exhaust duct 32. Similarly, various types of sensing methods such as an infrared method and a semiconductor method can be adopted. Here, the second gas detector 42 is disposed near the middle position of the exhaust duct 32, and the probe portion 421 is illustrated as protruding in the cylindrical internal space of the exhaust duct 32. The installation position of the second gas detector 42 is not limited to the mode shown in FIG. 1, but is located near the intake side of the ventilation fan 31 or near the exhaust side, near the inlet side 321 of the exhaust duct 32, or near the outlet side 322. May be.

  The collective device 50 is disposed in the vicinity of the site where the piping 21 on which emergency measures against gas leakage are present, and functions as a monitoring terminal for the site. The collective device 50 is provided with a warning lamp 501 (notification means) that is turned on when the danger level of gas leakage increases. The warning lamp 501 is, for example, an LED display lamp or a patrol lamp, and displays a warning according to the gas leakage state around the collecting apparatus 50. When this warning is displayed, a warning sound may be accompanied.

  The external device 60 includes a PHS terminal, a mobile phone, or a personal computer, and is connected to the collective device 50 via a communication line or the Internet. The external device 60 can acquire detection data by the first gas detector 41 and the second gas detector 42 collected by the collecting device 50, and thereby gas leakage at a remote place away from the indoor space 10. It is possible to perform remote monitoring.

  FIG. 2 is a block diagram illustrating an electrical configuration of the aggregation device 50. In addition to the warning light 501, the collective device 50 includes an interface 51, a ROM (Read Only Memory) 52, a RAM (Random Access Memory) 53 (storage means), a communication unit 54, a power supply 55, and a CPU (Central Processing Unit) 56. It has.

  The interface 51 is an interface for enabling the collecting apparatus 50 to perform data communication with the first gas detector 41 and the second gas detector 42.

  The ROM 52 stores a control program for the collective device 50 and various setting values. The RAM 53 temporarily stores data such as arithmetic processing and control processing, and stores detection data from the first gas detector 41 and the second gas detector 42 in association with sampling times. The detection data stored in the RAM 53 is disclosed when there is an access process from the external device 60. Further, the RAM 53 stores a setting value related to the gas concentration that is a criterion for determining the gas leakage risk level in the indoor space 10 (which will be described later with reference to FIG. 3).

  The communication unit 54 is a functional unit that transmits and receives data to and from the external device 60 via a communication network. The external device 60 can access the collective device 50 via the communication unit 54 and acquire information such as the time transition (for example, the past 1 to 6 hours) of the gas concentration detection data stored in the RAM 53. ing.

  The power supply 55 supplies operating power to each part of the collective device 50, and for example, an explosion-proof battery can be used. The operating power may be supplied to the collective device 50 from the outside via a power cord or the like.

  The CPU 56 controls the operation of each part of the collective device 50 and the operation of the first gas detector 41 and the second gas detector 42. The CPU 56 is functionally read by appropriately reading the control program stored in the ROM 52. The measurement control unit 561 and the determination processing unit 562 (determination unit) operate.

  The measurement control unit 561 causes the first gas detector 41 and the second gas detector 42 to perform detection operations at a predetermined sampling period (for example, 1 min), and causes the collective device 50 to acquire the detection data. Then, the acquired detection data is stored in the RAM 53 in association with the sampling time information.

  The determination processing unit 562 obtains the gas concentration in the indoor space 10 and the exhaust duct 32 based on the detection data of the first gas detector 41 and the second gas detector 42 (or the first gas detector 41 and the first gas detector 41). (2) Gas concentration data is acquired from the gas detector 42). Then, the obtained gas concentration is compared with the set value related to the gas concentration stored in the RAM 53 to determine the danger level related to the gas leakage state in the indoor space 10.

  FIG. 3 is a graph showing an example of setting the danger level. The gas concentration threshold indicated by “E” on the vertical axis in FIG. 3 is the lower limit value of the explosion limit, and in the case of city gas having a calorific value of 13 A, the gas concentration is 4.3%. Here, the gas concentration range of 1/100 to 1/4 of the explosion lower limit value E is set as a warning area (first danger level), and the gas concentration range of 1/4 to E of the explosion lower limit value E is set as the warning range. The example is set as an alarm area (second danger level) having a higher degree of danger than the warning information area. This danger level may be set according to the situation, or may be set in multiple stages of three or more stages.

  The determination processing unit 562 generates an alarm signal when the gas concentration in the indoor space 10 and / or the exhaust duct 32 reaches the above warning area or alarm area. This alarm signal is transmitted to the external device 60 via the communication unit 54. Further, a driving signal for the warning lamp 501 is generated based on the warning signal, and the warning lamp 501 is operated. The conditions for generating the alarm signal can be set as appropriate. For example, it is desirable to generate an alarm signal when detection data corresponding to a warning area or an alarm area is detected continuously for a certain period. For example, a warning signal is generated when detection data corresponding to the warning area is detected for 5 minutes continuously, and an alarm signal is generated when detection data corresponding to the warning area is detected for 1 minute continuously. Can be set to. As a result, the alarm signal can be prevented from being overrun.

  FIG. 3 also shows an example of detection data D1 and D2 by the first gas detector 41 and the second gas detector 42. The detection data D1 is detection data of the first gas detector 41, and the detection data D2 is detection data of the second gas detector 42. An operation example of the determination processing unit 562 will be described using the detection data D1 and D2.

  In FIG. 3, the detected data D2 generally has a higher concentration than the detected data D1 when the gas leakage occurs from the emergency treatment section and the ambient air around the emergency treatment section including the leaked gas. This is because the exhaust gas is forcedly exhausted from the indoor space 10 through the exhaust duct 32, so that the gas concentration in the exhaust duct 32 is higher than that in the indoor space 10. Therefore, it can be said that the detection data D2 is detection data indicating a state in a previous stage where the indoor space 10 actually reaches a dangerous state.

  At time T1, the detection data D1 and D2 both indicate gas concentration values below the warning area. In this case, the gas leakage from the emergency treatment unit is very small, and it can be said that the ventilation of the indoor space 10 by the ventilation device 30 is sufficiently in time.

  At the subsequent time T2, the detection data D2 indicates the gas concentration at the warning area level. At this time, the determination processing unit 562 transmits a first warning signal (first alarm signal). However, even at this time T2, since the value of the detection data D1 is at a low level below the warning range, it can be evaluated that the ventilation by the ventilation device 30 has caught up. The same applies to the detection data D1 at times T3 and T4.

  On the other hand, at time T5, the detection data D1 also indicates the gas concentration value at the level of the warning area. This indicates that the gas leakage state of the indoor space 10 has deteriorated so that ventilation by the ventilation device 30 can no longer catch up. In this state, the determination processing unit 562 transmits a second warning signal (second warning signal). It is possible to evaluate the momentum of gas leakage from the time difference between the time when the detection data D2 exceeds the level of the warning area and the time when the detection data D1 exceeds the level of the warning area. In the example of FIG. 3, it is the time difference between time T2 and time T5, but it can be evaluated that the shorter the time difference, the faster the gas leakage.

  Looking at the detection data D2, the gas concentration value at the alarm range is shown at time T4. In this case, since it is evaluated that the degree of danger of the indoor space 10 due to gas leakage is increased, the determination processing unit 562 transmits an alarm signal (third alarm signal). This alarm signal is transmitted when the detection data D1 becomes a gas concentration value of the alarm range or when both the detection data D1 and D2 become the gas concentration value of the alarm range. You may make it.

  According to the above configuration, the warning signal and the alarm signal are transmitted according to the stage of the danger level, so the administrator who owns the external device 60 takes an appropriate countermeasure according to the danger level. It is possible to take. In addition, when the detection data D1 indicates a gas concentration value at a level exceeding the explosion lower limit value E, the indoor space 10 cannot be entered. In this case, the determination processing unit 562 transmits an entry prohibition notification signal.

  In the above configuration, when the ventilation fan 31 of the ventilator 30 can be remotely controlled by the external device 60, and the detection data D1 or D2 is a gas concentration value at the level of the warning area or alarm area, the rotation speed of the ventilation fan 31 is set. You may make it raise and increase ventilation capacity.

  The operation of the gas leakage monitoring system S according to the present embodiment described above (particularly the danger level determination process) will be described based on the flowchart shown in FIG. Here, the flow will be described with reference to the setting example of the danger level shown in FIG. Further, the danger level is set at a level of 0 to 4 according to the degree of danger.

  When the operation of the system is started, the determination processing unit 562 of the collective device 50 sets the danger level = 0 as a default value (step S1). In this state, the measurement control unit 561 checks whether or not the sampling period has arrived (step S2). When the sampling period has arrived (YES in step S2), the measurement control unit 561 causes the first gas detector 41 to The detection data D1 and detection data D2 (instantaneous value) are acquired from the second gas detector 42, and the detection data D1 and D2 are associated with the sampling time information and stored in the RAM 53 (step S3).

  Next, the determination processing unit 562 determines whether or not the value of the detection data D2 is the value of the gas concentration level in the warning area (step S4). If the warning area level has not been reached (NO in step S4), the process returns to step S2 and is repeated. On the other hand, when the level of the warning area has been reached (YES in step S4), the determination processing unit 562 subsequently determines whether or not the detection data D1 is the gas concentration level of the warning area (step S5).

  When the detection data D1 has not reached the warning area level (NO in step S5), the determination processing unit 562 determines that only the exhaust duct 32 has reached the gas concentration level of the warning area, and the danger level = 1. (Step S6) and a first warning signal is transmitted (step S7). Thereafter, the process returns to step S1, and the danger level is reset to “0”.

  On the other hand, when the detection data D1 has reached the level of the warning area (YES in step S5), the determination processing unit 562 continues to determine whether the value of the detection data D2 or the detection data D1 is the value of the gas concentration level in the alarm area. It is determined whether or not there is (step S8). If neither of the detection data D1 and D2 has reached the alarm level (NO in step S8), the determination processing unit 562 has reached the gas concentration level in the warning area in the exhaust duct 32 and the indoor space 10 Is determined, and the danger level is set to 2 (step S9), and a second warning signal is transmitted (step S10). Thereafter, the process returns to step S1, and the danger level is reset to “0”.

  When the detection data D2 or the detection data D1 has reached the alarm level (YES in step S8), the determination processing unit 562 further determines whether or not the value of the detection data D1 exceeds the value of the gas concentration level in the alarm range. Is determined (step S11). If the value of the detection data D1 does not exceed the warning range (NO in step S11), the determination processing unit 562 determines that the exhaust duct 32 or the indoor space 10 has reached the gas concentration level in the warning range, and is dangerous. Level = 3 is set (step S12), and an alarm signal is transmitted (step S13). Thereafter, the process returns to step S1, and the danger level is reset to “0”.

  On the other hand, if the value of the detection data D1 exceeds the warning range (YES in step S11), the determination processing unit 562 determines that the indoor space 10 has become inaccessible and sets the danger level = 4. (Step S14), an entry prohibition signal is transmitted (Step S15). Thereafter, the process returns to step S1, and the danger level is reset to “0”.

  According to the gas leakage monitoring system S according to the present embodiment described above, the first gas detector 41 is installed in the indoor space 10 and the second gas detector 42 is arranged in the exhaust path of the indoor space 10. Therefore, a change in the degree of gas leakage from the pipe 21 can be accurately detected at an early stage. Therefore, it is possible to take measures against gas leakage in the indoor space 10 at a stage where the degree of danger is low.

  As described above, in order to express the present invention, the present invention has been described appropriately and sufficiently through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this can be done. Accordingly, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not limited to the scope of the claims. To be construed as inclusive.

It is the schematic which shows the hardware constitutions of the gas leak monitoring system S which concerns on embodiment of this invention. 3 is a block diagram showing an electrical configuration of the aggregation device 50. FIG. It is a graph which shows the example of a setting of a danger level. It is a flowchart which shows operation | movement (especially determination processing of a dangerous level) of the gas leak monitoring system S. FIG.

Explanation of symbols

S Gas leakage monitoring system 10 Indoor space 20 Piping system 21 Piping (gas distribution piping)
22 Fastening band (first aid department)
30 Ventilator (ventilation means)
31 Exhaust fan 32 Exhaust duct (exhaust path)
41 1st gas detector (1st gas detection means)
42 Second gas detector (second gas detection means)
50 Aggregation device (data aggregation device)
501 Warning light (notification means)
51 Interface 52 ROM
53 RAM (storage means)
54 Communication Unit 55 Power Supply 56 CPU
561 Measurement control unit 562 Determination processing unit (determination means)
60 External equipment

Claims (9)

Ventilation means for ventilating indoor spaces where gas distribution pipes exist;
First gas detection means installed in the indoor space;
Second gas detection means arranged in the exhaust path of the indoor space by the ventilation means;
A data collection device for collecting detection data by the first and second gas detection means;
A gas leakage monitoring system comprising:   The gas leakage monitoring system according to claim 1, wherein the ventilation means ventilates an indoor space where a gas distribution pipe subjected to an emergency measure for suppressing gas leakage is present. The ventilation means includes an exhaust duct as the exhaust path,
The gas leakage monitoring system according to claim 1, wherein the second gas detection means is disposed in the exhaust duct.   The gas leakage monitoring system according to claim 1, wherein the data collection device includes storage means for storing the detection data at a predetermined sampling period. An external device communicably connected to the data aggregation device via a communication network;
The gas leakage monitoring system according to claim 1 or 4, wherein the external device is capable of acquiring detection data collected by the data collection device. The data aggregation device is
The apparatus includes a determination unit that obtains gas concentrations in the indoor space and the exhaust path based on the detection data, and that determines a gas leakage state by comparing a predetermined determination criterion with the gas concentration. The gas leakage monitoring system according to any one of claims 1 to 5.   7. The gas leakage monitoring system according to claim 6, wherein the determination means transmits an alarm signal when it is determined that the gas concentration in the indoor space and / or the exhaust path exceeds a predetermined level. . The determination means includes a first gas concentration set as a first danger level and a second gas concentration set as a second danger level that is higher in risk than the first danger level. As a judgment criterion,
When the gas concentration based on the detection data of the second gas detection means exceeds the first gas concentration, a first alarm signal is transmitted,
When the gas concentration based on the detection data of the first gas detection means exceeds the first gas concentration, a second alarm signal is transmitted,
When a gas concentration based on detection data of the second gas detection means and / or the first gas detection means exceeds the second gas concentration, a third alarm signal is transmitted;
The gas leakage monitoring system according to claim 7.   The gas leakage monitoring system according to claim 7 or 8, wherein the data collection device includes a notification unit that performs a predetermined notification operation when the alarm signal is transmitted.

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