JPH09236506A - Gas leakage detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a gas leakage detector which can specify a leaking part of flammable gas, for example, in a running vehicle. SOLUTION: This title device is provided with a gas detecting mechanism 4 to detect a flammable gas, and further is provided with pheromone detecting mechanism 5 for detecting the pheromone density, a position confirmation mechanism 70 for searching own position of the device, and a storage means 71 for storing correlatively an information on pheromone density detected from the mechanism 5 and an information on device position. On the basis of the storage information which is stored with time in the means 71, the leakage of gas or the position of gas leakage can be detected or estimated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the detection of flammable gas leaks, for example, for checking gas leaks that occur in gas conduits laid over a wide area and for detecting the location of gas leak sites. Regarding the detection device.

[0002]

2. Description of the Related Art Conventionally, for gas leak detection of combustible gas,
A flammable gas sensor having a gas sensing element made of a metal oxide semiconductor in a sensitive part has been used. When detecting the position of the gas leakage site using this gas leakage detection device, the worker walks on the gas conduit together with the gas leakage detection device at a slow speed (about 2 km / h) and within a predetermined range. They had to move all the way through, detect, check for gas leaks, monitor safety, identify leak locations, etc.

[0003]

However, for example, when a gas conduit buried in the soil is targeted, there are the following problems. 1 Gas leaked in soil is considerably diluted by diffusion and adsorption in soil. 2 Furthermore, for example, when the target is city gas, it easily diffuses when it is released into the air, and is further diluted. Despite such a situation, the current sensor (using a metal oxide semiconductor) has a relatively low sensitivity (the mentor detection limit is 10 ppm), and it can detect only a high concentration gas and Takes time. Therefore,
In fact, unless many sensors are prepared, only point detection can be performed. At present, it is impossible to monitor a relatively wide range with high reliability in a relatively short time. That is, in the present situation, only the nearest part of the gas conduit can be detected or detected, and for example, a vehicle is equipped with a gas leakage detection device to monitor gas leakage in a wide area while traveling, It is not possible to identify the leak site. Further, the combustible gas sensor has a low specificity with respect to the combustible gas and reacts with a non-detecting gas such as an exhaust gas of an automobile, so that it often malfunctions. Further, since flammable gas is also present in nature, it is likely to cause a problem if the sensitivity is increased more than the current level. Therefore, an object of the present invention is to eliminate the above problems.

[0004]

To achieve this object, the gas detector according to the present invention is characterized by a pheromone detecting mechanism for detecting the pheromone concentration and a position confirming mechanism for confirming the position of the pheromone detecting mechanism. And storage means for storing the pheromone concentration detection information from the pheromone detection mechanism and the device position information from the position confirmation mechanism in association with each other, and from the time-storing information stored in the storage means over time, the gas The purpose is to determine the presence / absence of a leak or the gas leak estimated position estimated to be the gas leak position. [Operation / Effect] The gas leak detection apparatus of the present application includes a gas detection mechanism capable of detecting the gas side and a pheromone detection mechanism capable of detecting the pheromone side up to its concentration. Further, a position confirmation mechanism is provided, and the device position information from this position confirmation mechanism and the information associated with the pheromone concentration detection information from the pheromone detection mechanism can be stored in the storage means. Therefore, for example, when the gas leak detection device of the present application is mounted on an automobile or the like and moved in a predetermined area, the pheromone concentration distribution in the area can be easily obtained. For this purpose, when the apparatus of the present application is used, for example, the pheromone is allowed to flow at a predetermined concentration together with the gas in the gas conduit to be detected. By doing so, the pheromone that leaks together with the gas can be detected from the gas leaking site generated in the gas conduit. First, the properties of pheromones and gases will be described. Generally, the detectable limit of pheromones is much lower than that of combustible gases. Therefore, for example, it is possible to detect this even from a position separated by about 80 m. On the other hand, the flammable gas sensor is relatively high, and can only detect from a position several meters away at most. In such a situation, since the molecular weight of the pheromone is larger than that of the flammable gas (for example, methane), the pheromone is difficult to diffuse and the concentration distribution is easily formed. On the other hand, the gas easily diffuses and the concentration distribution is hard to appear. Rather, it is the actual situation that at a very low concentration below the detection limit, it diffuses over a wide range and cannot be detected. Therefore, in the device of the present application, using the pheromone as an index, the pheromone concentration distribution in a predetermined area is obtained from the remote position based on the information of the detection position which is the device position and the pheromone concentration information of the site, and the concentration thereof. The estimated gas leak position is detected while referring to the gradient. If necessary, then, for confirmation, the presence or absence of flammable gas is checked at this estimated gas leakage position. In this way, when the presence of the flammable gas is confirmed, this estimated position can be determined as the position where the gas leakage site exists. That is, when searching for a gas leakage position in a relatively wide range, which was impossible in the past, proceed with the work on the pheromone side suitable for this, and confirm the presence of flammable gas as the final confirmation work. You can Here, the fact that the detection of the combustible gas is substantially the pinpoint detection has the opposite effect, and the position identification becomes easy and reliable. Therefore, when the device of the present application is adopted, gas leakage monitoring over a wide area can be reliably performed in a relatively short time. For example, depending on the state of the buried soil, when targeting a gas conduit, the presence or absence of gas leakage can be detected within a radius of 50 meters, even when considering the conditions of the piping, the buried soil, etc. If a leak is confirmed, its direction can be inferred. Furthermore, since the electon antenogram (hereinafter referred to as EAG) provided in the pheromone detection mechanism has very high peculiarity, there are very few malfunctions in the detection of pheromones, and when used together with the detection of flammable gas, the accuracy of detection is high. Can be improved.

[Configuration] In the above configuration, the gas leak detection device is configured to be mounted on a mobile vehicle that is movable on the ground, and the gas detection mechanism and the sensitizing portion of the pheromone detection mechanism are connected to the mobile vehicle. It is preferable that the lower part of the vehicle body can be arranged so as to be exposed to the outside air. [Operation / Effect] As described above, the gas leak detection apparatus of the present application monitors based on a pheromone, so that a wide range can be monitored, and this can be monitored quickly and reliably. Therefore, this device can be mounted on a moving vehicle such as an automobile, a motorcycle, a bicycle, or a wheelbarrow, and can be monitored while moving.
For this purpose, the device is configured to be mountable on a moving vehicle, and moreover, a sensitive part, which is a sensor part provided in each detection mechanism, is arranged under the vehicle body in an exposed state of the outside air. With this configuration, for example, the pheromone and the gas leaking from the gas conduit buried in the ground can be well detected. [Configuration] Further, in the above configuration, it is preferable that the position confirmation mechanism is a global positioning system. [Operation / Effect] The gas leak detection device of the present application is basically equipped with a detection mechanism on the pheromone side. It is possible to position the leakage site. Furthermore, in such monitoring work and leak location determination, it is necessary to accurately find the concentration distribution of the pheromone in the monitored area. However, by providing a global positioning system as a position confirmation mechanism, The position of the pheromone can be accurately and quickly determined, and accurate information on the distribution of the pheromone can be obtained. Therefore, it is possible to satisfactorily monitor the gas leakage, which was impossible in the past. [Configuration] Further, in the above configuration, the moving vehicle may be an automobile, and the position confirmation mechanism may obtain the device position based on output position information from a car navigation system mounted on the automobile. preferable. [Operation / Effect] Today, automobiles are equipped with car navigation systems, which are a specific example of global positioning systems, and play a role such as the position of the automobile on the road, the traveling direction, the road guidance, and the display of the destination. ing. This car navigation system has the position information of the vehicle, and the position confirmation mechanism can confirm the position of the device by obtaining the position information of the vehicle (substantially the position information of the gas leak detection device) from this system. With this, the gas leak detection device described so far can be obtained with a relatively simple structure.

[0006]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a situation in which the gas leak detection apparatus 1 of the present application is used to detect a gas leak site 3 that has occurred in a city gas conduit 2. As shown in FIG. 2, the gas leak detection device 1 includes a gas detection mechanism 4 capable of detecting the presence or absence of a combustible gas to be detected and its concentration, and a pheromone detection mechanism capable of detecting the presence or absence of a pheromone and its concentration. 5 and combustible gases (methane, ethane, butane, etc.) that are the main components of city gas, and pheromones can be detected. As shown in FIG. 1, the gas leak detection device 1 is mounted on an automobile 6 on which an operator rides, and moves along with the automobile 6 to detect a gas leakage site 3
It is configured so that the worker can carry out the work while holding the device by hand after getting off the vehicle. In the detection work, as shown in FIG. 1, a pheromone is injected into the gas conduit 2, and this pheromone leaks from the leak site 3 of the gas conduit 2. Therefore, the position of the leakage site 3 can be specified by detecting this pheromone. Here, the position of the gas detection device 1 is sequentially monitored by a position confirmation mechanism 70 (GPS, which is a so-called global positioning system) provided in the device 1, and the position of the detection device 1 (substantially the location of the automobile 6 is detected). While confirming the position), it is possible to grasp the change status of the pheromone concentration at each detection position and proceed with the work. Then, the pheromone side monitored the presence or absence of gas leaks in a relatively wide range of monitoring areas, and if there was a possibility of gas leaks, the pheromone side also roughly determined the position of the gas leak site. After that, the presence of flammable gas is confirmed, and the occurrence of certain gas leakage is confirmed, and the work is finished. For this purpose, the gas leak detection device 1 is configured to switch the operation of each of the detection mechanisms 4 and 5 between the gas detection state in which the gas detection mechanism 4 operates and the pheromone detection state in which the pheromone detection mechanism 5 operates. 8 and further stores a procedure for detecting the position 3 of the gas leakage site where the flammable gas leaks, and at the predetermined stage of this procedure, it works together with the detection analysis means 11 to be described later, and A gas leak position detecting means 9 for outputting a movement instruction to the monitor image display device 12 is provided. Therefore, the operation of detecting the gas leakage portion proceeds according to this procedure while the switching means 8 is operating.

First, the structure of the gas leak detection device 1 will be described below. The gas leak detection device 1 includes the gas detection mechanism 4 and the pheromone detection mechanism 5 described above. The gas detection mechanism 4 includes a hydrocarbon gas sensor 4a to which a metal oxide semiconductor such as tin oxide is applied, and a processing means 4b for amplifying and analyzing the sensor output, and a control circuit and a control which will be described later on the sensor output. It is configured so that it can be converted into data suitable for processing by the control means 10 composed of a computer for use and software stored in the computer. The pheromone detection mechanism 5 is provided with a pheromone sensor 5a based on the above-mentioned electonoantenogram (EAG) to which a pheromone-sensing mechanism such as an insect tactile sense or a reactor is applied, and a processing means 5b for amplifying and analyzing the sensor output. Has been done. EAG is a pheromone sensor 5a devised by Schneider in 1957. The system as shown in FIG. 2 amplifies the change in the electric potential of the nerve of the sense of touch 50 when the sense of touch 50 of an insect detects the pheromone. , Which is captured as an electric signal. Since the electromotive force is proportional to the pheromone concentration, the concentration of the pheromone present at the detection site can be grasped by the difference in the electromotive force. In the gas detection mechanism 4 and the pheromone detection mechanism 5, the hydrocarbon gas sensor 4a and the pheromone sensor 5a, which are the respective sensitive parts, are configured to be extendable from the mechanism main body, and the detection device can be moved to a vehicle or the like. When mounted on a car, each sensor 4a, 5a
It is configured so that it can be freely arranged in the lower part of the vehicle body of a moving vehicle in an exposed state. The outputs from these detection mechanisms 4 and 5 are sent to the control means 10 described above. The control means 10 stores the switching means 8, the gas leak position detection means 9, the storage means 71, the detection analysis means 11, and the position confirmation means 7 described above. The position confirmation mechanism 70 includes an external antenna 7a, which is a ground-side device of the global positioning system, and a position confirmation means (software) 7 provided in the control means 10, which is input via the external antenna 7a. The position of the gas leak detection device 1 is confirmed based on the GPS information. Further, the storage means 71 which stores the pheromone concentration detection information from the pheromone detection mechanism 5 and the device position information from the position confirmation mechanism 70 described above in association with each other.
Is provided. Further, the control means 10 is provided with the detection analysis means 11 and is configured so that a further detection movement command can be derived based on the information stored in the storage means 71 at each stage of the procedure. Has been done. With the above configuration, it is possible to determine the presence or absence of a gas leak, or the gas leak estimated position estimated to be the gas leak position, from the time-lapse memory information stored in the storage means 71 over time. Further, the control means 10 includes
A monitor image display device 12 is provided with a keyboard for inputting / outputting information. The above is the outline of the configuration of the gas leak detection apparatus 1 of the present application.

A procedure for specifying the position of the gas leakage portion 3 in the gas conduit 2 will be described below with reference to FIG. 4 and 5 used for the explanation are respectively
The former is an explanatory view showing the movement state of the device 1 in the detection, and the latter is data showing the pheromone concentration distribution when the device 1 makes a linear movement in a specific direction. In such detection work, it is premised that the pheromone is mixed with the gas in the gas conduit 2.
Specifically, city gas containing bobbin call, which is a pheromone of Bombyx mori, at a concentration of 1 ppb in the gas conduit 2 (95%
The above is aeration of methane. Therefore, both the pheromone and the gas leak from the gas leak site 3 in FIG.

The operation will be described below in accordance with the work procedure shown in FIG. a Steps 1 and 2 (ST1, ST2) In this situation, in the gas leak detection device 1, the pheromone detection mechanism 5 is activated to search whether or not the pheromone is detected. In this case, the determination of the minute leak is based on the leak rate of 5 liters / hour. Since it is a detection in the running state of the automobile 6, it is a detection at a remote point. However, if a leak occurs in the above state, at a point about 80 meters away from the gas leakage site 3,
It is possible to detect 1.0 × 10 ⁻⁷ ppb pheromones. Therefore, an area having a diameter of about 160 meters can be covered. When no pheromone is detected, it is assumed that no gas leakage has occurred in the detection peripheral area, and the movement of the device 1 is continued. In reality, the worker continues to drive the automobile 6. b Steps 3 and 4 (ST3, 4) When the presence of the pheromone is confirmed in Step 1, get off at this position (this position is called the specific detection position Q), hold the gas leak detection device 1, and have a radius of 3 meters. Rotate about 180 degrees (moves in the circumferential direction around the specific detection position Q) to obtain the circumferential pheromone concentration distribution. Then, the direction in which the pheromone concentration is high (the direction in which the position where the pheromone concentration is the maximum from the specific detection position Q is expected, indicated by A in the figure) is defined as the direction in which there is a leakage site (this direction is called the detection direction A). This processing is automatically performed by the detection analysis means 11 described above. c Step 5 (ST5) A change in the pheromone concentration is detected while moving along the specified detection direction. The change in the pheromone concentration on the gas conduit 2 predicted to have the gas leakage site 3 is shown in FIG. In the figure, the horizontal axis represents the distance from the gas leakage site in m units, and the vertical axis represents the pheromone concentration. d Steps 6 and 7 (ST6, 7) The position where the pheromone concentration is maximum is confirmed (this processing is also automatically performed by the detection analysis means 11 described above), and if necessary, the process returns to that position. Here, at the position where it is determined that the pheromone concentration shows the highest concentration, the gas leak detection device 1 is configured to generate an alarm sound. Furthermore, the worker examines the vicinity in detail,
Furthermore, reconfirm the identification of the site with the highest pheromone concentration. e Step 8 (ST8) When it is determined that the pheromone concentration is the highest or when it is determined that the pheromone concentration is equal to or higher than a predetermined value, the alarm lamp of the device 1 is turned on and the switching means 8 instructs the gas leak position detection means 9 to instruct. To operate. Therefore, when such a determination is made, the device 1 automatically switches to the detection state of the gas detection mechanism 4. f Steps 9, 10 and 11 (ST9, 10 and 11) Then, when a combustible gas (mainly composed of methane) is detected by the detection by the gas detection mechanism 4, the current gas leak detection device 1 A certain position is judged as the position where the gas leak is occurring. On the other hand, when the gas is not detected and only the pheromone is detected, it is not confirmed that the gas leak occurs. g Thus, the work is completed.

In the above description, regarding the gas leak position detecting means 9, this role was explained only in the case of the command output to the switching means 8, but basically,
The gas leak position detection means 9 controls macro control of work procedure and control of external input / output, and the detection analysis means 11 described above specifies the detection direction A from the information stored in the storage means 71. , Is responsible for specifying the maximum position P of the pheromone concentration.

[Another Embodiment] Another embodiment of the present application will be described below. 1 In the above example, the moving vehicle is mainly an automobile, but as described above, this is a motorcycle,
It may be a bicycle or a wheelbarrow that can move at a relatively high speed. 2 Furthermore, in the above example, the gas leakage detection device itself is used as a position confirmation mechanism in the global positioning system (GPS).
However, in the case of so-called automobiles, it is now popular to equip such automobiles with a car navigation system. Since this car navigation system has the position information of the automobile, the position confirmation mechanism of the device of the present application is connected to this system so that the position confirmation mechanism can obtain the device position from this system and perform position confirmation. It is preferable to keep it from the viewpoint of simplification of the device. This structure is shown in FIG. 3 In the above examples, Bombykol, which is a pheromone of Bombyx mori, was adopted, but as the pheromone, periplanone-A of the American cockroach, Culua of the fruit fly, Little A of the common lotus, Z-2-hexadecenyl acetic acid of the pearl millet, Z- of the stag beetle. Methyl 5-tetradecenoate, R, Z-5- (1-decenyl) of Mannequin
Dihydro-2 (3H) -furanone and the like can also be used. Some of these pheromones have a relatively high probability of seasonal or regional existence, and as in the present application, confirmation is made from both the pheromone and gas perspectives to determine whether gas leakage has been confirmed. Further, it is preferable to further specify the position of the gas leakage site. Furthermore, in general, when targeting city gas, etc., the odorant is mixed in the city gas, so it is necessary to confirm the existence of two or more of the pheromone, the flammable gas, and the odorant. It may be possible to use a device for advancing work.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the accompanying drawings.

[Brief description of drawings]

FIG. 1 is a diagram showing a situation in which the location of a leak portion of a city gas conduit is being detected.

FIG. 2 is a conceptual diagram of the configuration of a gas leak detection device.

FIG. 3 is a diagram showing a flow of gas leak detection.

FIG. 4 is a diagram showing a movement situation in the detection work.

FIG. 5 is a diagram showing a relationship between a leakage site and a change situation of pheromone concentration.

FIG. 6 is a diagram showing a configuration of a gas leak detection device configured to work together with a car navigation system.

[Explanation of symbols]

 4 Gas Detection Mechanism 5 Pheromone Detection Mechanism 70 Position Confirmation Mechanism 71 Storage Means

Claims (4)

[Claims] 1. A gas leak detection device comprising a gas detection mechanism (4) for detecting a combustible gas, the pheromone detection mechanism (5) for detecting a pheromone concentration, and a position confirmation mechanism (70) for determining a device position. ) And storage means (71) for storing the pheromone concentration detection information from the pheromone detection mechanism (5) and the device position information from the position confirmation mechanism (70) in association with each other, the storage means (71).
A gas leak detection device for determining whether or not a gas leak has occurred, or a gas leak estimated position estimated to be a gas leak position, from time-lapse stored information that is stored over time. 2. A movable vehicle that is movable on the ground is configured to be freely mounted, and the sensitive portions of the gas detection mechanism (4) and the pheromone detection mechanism (5) are provided in the movable vehicle (6).
2. The gas leakage detection device according to claim 1, wherein the gas leakage detection device is configured so as to be freely arranged in a lower portion of the vehicle body in an exposed state of outside air. 3. The gas leak detection device according to claim 1, wherein the position confirmation mechanism (70) is a global positioning system. 4. The moving vehicle is an automobile (6), and the position confirmation mechanism (70) obtains the device position from output position information from a car navigation system equipped in the automobile (6). Item 1. A gas leak detection device according to item 1 or 2.