JP2003294567A - Gas leak visualizing and distance measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To visualize the gas leak state even from a separated position, and to measure the distance to the leak position. <P>SOLUTION: A region where hydrocarbons 3 leak from a gas pipe 2 or the like is irradiated with visualizing infrared rays 4 from a light emitting part 6. The visualizing infrared rays 4 include infrared rays having two wavelengths, namely, an absorption wavelength λON absorbed by the hydrocarbons and a nonabsorption wavelength λOFF. Reflected light is received by a light receiving element 30, and a concentration distribution of the hydrocarbons 3 can be acquired on a visualizing screen 9 as a leak state image 10 from comparison of the light receiving intensity by an image processing circuit 32. Distance measuring infrared rays 5 having the wavelength λL not absorbed by the hydrocarbons 3 are also irradiated from the light emitting part 6, and received by the light receiving element 30. The position where the hydrocarbon 3 concentration becomes maximum is supposed as a leak spot, and the distance to the position is measured by a distance measuring circuit 33, and can be displayed on the visualizing screen 9 as a distance display 12. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas leak visualization and distance measuring device for visualizing a leak location of a hydrocarbon compound gas or the like to measure a distance.

[0002]

2. Description of the Related Art Conventionally, a city gas containing methane, which is one of the hydrocarbon compounds, as a main component has a unique odor, although it is odorless in nature, so that it is easy to recognize that there is a leak. ing. It also detects the presence of methane,
Gas leak alarms that give an alarm when the concentration exceeds the standard value are also used. When a city gas leak is detected,
It is necessary to clarify the cause and take countermeasures. If the leak is noticeable, such as when the hose comes off, the user can easily find the cause and stop the leak. If the cause is a slight leak in the middle of the pipe, the pipe is often buried in the ceiling or wall, and unless a specialist is dispatched, the leak location is detected and leak prevention repairs are performed. Is impossible.

[0003]

For example, when it is determined that gas leaks from a gas pipe laid behind the ceiling, it is necessary to suspend and expose the ceiling at the leak location. In many cases, the ceiling is provided with an inspection port that can be partially opened, but if the leaking points are far apart, the actual leaking points must be exposed by means of chipping. I do not know. Moreover, if the amount of leakage is very small, it is often difficult to understand even if it is exposed by chipping. For this reason, the leaking point cannot be found unless the climbing range is considerably widened and sufficient time is taken. If the ceiling and other areas are widened, the chipping work itself and the repairing work after the chipping will take a lot of time and labor, and a large amount of repair costs will be required.

It is an object of the present invention to provide a gas leakage visualization and distance measuring device capable of visualizing a gas leakage state even from a distant position and measuring the distance to the leakage position.

[0005]

The present invention provides an absorption infrared ray having a wavelength absorbed by a gas to be visualized and a non-absorption infrared ray having a wavelength not absorbed by the gas.
Irradiate the space where there is a possibility of gas leakage, receive the absorbed infrared rays and the non-absorbed infrared rays that have passed through the space and are reflected,
Visualization is performed to perform image processing to calculate the distribution state of the leak concentration of the gas based on the ratio of the amount of received light of the absorbed infrared ray and the non-absorbed infrared ray, and visualize the distribution state of the leak concentration in the image of the space as the leak state. Means and a region including a position in the space corresponding to a position where the concentration is maximized in a leakage concentration distribution state visualized by the visualization device is irradiated with ranging infrared light having a wavelength not absorbed by the gas, A gas leak visualization and distance measuring device comprising: a distance measuring unit that receives distance measuring infrared rays reflected from inside and calculates a distance to the area.

According to the present invention, visualization is performed by utilizing the property that gas absorbs infrared rays having a specific wavelength. The visualization means irradiates a space having a possibility of gas leakage with an absorption infrared ray having a wavelength absorbed by a gas to be visualized and a non-absorption infrared ray having a wavelength not absorbed by the gas. If there is a gas to be visualized, the absorbed infrared light radiated into the space is absorbed and attenuated by the time it passes through the space, is reflected by a wall, etc., and is received. It will be larger than. Image processing is performed to calculate the distribution state of the leakage concentration of gas based on the ratio of the amount of received light of the absorption infrared ray and the non-absorption infrared ray, and since the distribution state of the leakage concentration is visualized as the leakage state in the image of the space, If there is a leaking point, the density is high in the vicinity of the leaking point and it can be visualized as an image. The range-finding means irradiates a range-finding infrared ray having a wavelength that is not absorbed by the gas, to a region including a position in the space corresponding to the position where the concentration becomes maximum in the distribution state of the leak concentration visualized by the visualization means, It receives the range-finding infrared rays reflected from within the area. Even if the concentration of the gas is high, the distance measuring infrared ray having the wavelength that is not absorbed by the gas is used, so that the distance to the position where the leakage is likely to occur can be calculated without being affected by the leakage gas. . Since it is possible to obtain the image and distance of the leaked part, even at the leaked part such as the ceiling, the infrared rays are radiated and received from the inspection port to be visualized, and the position of the leaked part is accurately determined based on the distance. However, it is possible to improve the precision when mounting the ceiling, minimize the mounting range, and reduce repair costs.

Further, the visualization means includes expansion means for expanding the absorption infrared rays and the non-absorption infrared rays into a pyramidal light flux, and the distance measuring means maximizes the leak density. The distance measuring infrared ray may be applied to the region via the measurement position adjusting mechanism at the timing when the measuring position adjusting mechanism emits the light flux in the direction including the position.

According to this construction, in order to visualize the leaked state, the range-finding infrared ray is radiated to the leaked portion by utilizing the expansion means for expanding the irradiation of the absorption infrared ray and the non-absorption infrared ray. It is possible to measure the distance by using the image for determining the leakage location.

Further, the present invention is characterized by further comprising light receiving means for commonly receiving the absorption infrared ray, the non-absorption infrared ray and the distance measuring infrared ray.

According to the present invention, since the absorption light and the non-absorption infrared light for visualizing the gas and the distance measurement infrared light for distance measurement are commonly received by the light receiving means, the structure of the device is simplified and the manufacturing is performed. The cost can be reduced. Since both the non-absorbing infrared ray for visualization and the ranging infrared ray for distance measurement are infrared rays having a wavelength that is not absorbed by the gas to be visualized, the light receiving means can be made common and the irradiation side can be made common. .

[0011]

1 shows a schematic configuration of a gas leakage visualization and distance measuring device 1 according to an embodiment of the present invention. Gas leak visualization and distance measuring device 1 of the present embodiment
Makes the hydrocarbon 3 which is the main component of the gas leaking from the gas pipe 2 visible as an image according to the leak concentration. The region where the hydrocarbon 3 is likely to leak is irradiated with the visualization infrared ray 4 and the distance measuring infrared ray 5 from the light emitting unit 6. The irradiated infrared ray 4 and distance measuring infrared ray 5 pass through the area where the hydrocarbon 3 leaks, are reflected by the surface of the wall 7 or the like, and reach the light receiving portion 8. The light-receiving unit 8 includes a visualization screen 9, displays a leak state image 10 of the hydrocarbon 3 and a gas pipe image 11 that is the source of the leak, and displays a numerical value of the measured distance on the distance display 12. You can

The light emitting section 6 includes a laser light source 20 and emits infrared laser light having a plurality of wavelengths. Laser light source 20
Includes a leakage detection laser 21, a wavelength stabilization circuit 22, a hydrocarbon cell 23, an alignment mechanism 24, and the like. From the leak detection laser 21, an absorption infrared ray having a wavelength λON that is absorbed by the hydrocarbon 3 and a non-absorption infrared ray having a wavelength λOFF that is not absorbed by the hydrocarbon 3 are generated as the visualization infrared ray 4. Further, the infrared ray 5 for distance measurement having the wavelength λL which is not absorbed by the hydrocarbon 3 is also generated.
The infrared ray 5 for distance measurement can be shared with the non-absorbing infrared ray of the infrared ray 4 for visualization. The wavelength stabilization circuit 22 selects the absorption infrared ray through the hydrocarbon cell 23 and stabilizes the output wavelength of the leak detection laser 21.

The light receiving unit 8 includes a visualization screen 9 and a light receiving element 30 and a processing circuit 31. The light receiving element 30 is
It is formed by arranging minute light receiving cells in a planar shape, a linear shape, or a dot shape. The processing circuit 31 includes an image processing circuit 32 and a distance measuring circuit 33. The image processing circuit 32 performs arithmetic processing on the electric signal generated by the light receiving element 30 based on the light reception, and generates an image according to the leakage concentration displayed on the visualization screen 9. The distance measuring circuit 33 irradiates the distance to the supposed leak point in the gas pipe 2 near the high concentration region of the hydrocarbon 3 with the infrared ray 5 for distance measurement, and the time difference between the time of irradiation and the time of reception, The distance to the leakage point of the gas pipe 2 is calculated from the shift of the position of incidence on the light receiving element 30.

FIG. 2 shows a typical use state of the gas leakage visualization and distance measuring device 1 of this embodiment. When the gas pipe 2 in which the hydrocarbon 3 is leaking is present behind the ceiling plate 40, first, the visualization screen 9 in FIG.
In addition, since the leakage state image 10 is formed, it is possible to detect that leakage has occurred and obtain the distance L to the leakage location. The space between the ceiling board 40 and the actual ceiling is narrow, and the strength of the ceiling board 40 is not sufficient.
It is impossible for humans to move over 0. Inspection port 4
Since the direction of the leaked portion is known from the irradiation direction from 1, the position of the repaired portion 42 can be accurately obtained with respect to the ceiling plate 40 if the distance L can be obtained.
The repair area 42 can be exposed by limiting the range over which the repair is performed.

FIG. 3 shows the principle of visualizing the hydrocarbons 3 at the time of gas leakage in the gas leakage visualization and distance measuring device 1 of this embodiment. The hydrocarbon 3 has a property of absorbing infrared rays having a specific wavelength (frequency). The light emitting unit 6 irradiates the absorption infrared ray having the wavelength λON absorbed by the hydrocarbon and the non-absorption infrared ray having the wavelength λOFF not absorbed by the hydrocarbon. Since the irradiated infrared rays are reflected by the wall 7 and the ground, the light receiving unit 8
Receive at. The received light output from the light receiving element 30 that receives the two received wavelengths λON and λOFF is compared, and if the absorbed infrared light is smaller than the non-absorbed infrared light, the hydrocarbon 3
It turns out that exists. Further, the decrease amount of the received light output is proportional to the concentration of the hydrocarbon 3.

From the leak detection laser 21 of FIG.
A non-absorbing infrared ray having a wavelength λOFF different from that of ON is also generated to irradiate a space including an object such as the gas pipe 2 with an infrared laser beam of two wavelengths and receive reflected light from the wall 7 or the ground. When the hydrocarbon 3 is present in the range of the space irradiated with the infrared laser light of two wavelengths, the received light intensity of the absorption wavelength λON becomes lower than the received light intensity of the non-absorption wavelength λOFF, so that each received light is detected. The leakage concentration of the hydrocarbon 3 can be obtained from the comparison of the reflected light intensities. The absolute value of the concentration can also be obtained by previously testing and confirming the concentration at which leakage can be detected.

In order to obtain the leaked state image 10 as shown in FIG. 1, the infrared laser light which spreads in a pyramid shape is irradiated and the reflected light is detected by the light receiving element 30. Thereby, the concentration distribution can be measured. By performing image processing in the image processing circuit 32 based on this density distribution, the leak state image 10
Can be visualized as.

FIG. 4 shows an image in which the leakage state of the hydrocarbon 3 is visualized by the gas leakage visualization and range finder 1 of this embodiment. Gas leak visualization and ranging device 1
Is formed using a so-called notebook personal computer or the like. For example, the visualization screen 9 in FIG. 1 uses a display screen such as a liquid crystal display device. The light emitting unit 6 and the light receiving element 30 of FIG. 1 are added as an adapter.

FIG. 5 shows a procedure for operating the gas leakage visualization and distance measuring apparatus 1 of this embodiment to visualize a hydrocarbon leakage state and measure a distance. Turn the power on at step s0
After turning on N and performing a warm-up operation, in step s1, the laser light source 20 of FIG. At step s2, the absorbed infrared rays are received. At step s3, the wavelength λO is emitted from the laser light source 20.
Outputs non-absorption infrared rays from FF. In step s4, the non-absorption infrared rays are received. In step s5, the light from the background is received. In step s6, the laser light source 20 outputs the infrared ray 5 for distance measurement having the wavelength λL. This output is performed at the timing of sweeping the position after the position of the maximum leakage concentration is obtained. In step s7, the infrared ray 5 for distance measurement is received. After step s7, the process returns to step s1 and steps s1 to s7 are repeated.

Based on the infrared ray 5 for distance measurement received in step s7, in step s8, the distance measuring circuit 33 of FIG.
Performs distance measurement processing to obtain distance information. In the next step s9, the leakage state image 10, the gas pipe image 11 and the distance display 12 as shown in the visualization screen 9 of FIG. 1 are performed.
Absorption wavelength λ received in steps s2 and s4
Since the background light is received in step s5 in addition to the image of ON and the non-absorption wavelength λOFF, noise can be reduced. Difference processing is performed on the images of the absorption wavelength λON and the non-absorption wavelength λOFF, and the difference image is superimposed on the image of the non-absorption wavelength λOFF. From the distance information and the difference information, the position with the maximum leak amount is obtained, and the distance to that position is calculated. The leakage position and the distance to the leakage position are displayed in the visualization screen 9. The position where the amount of leakage is maximum can also be obtained as the position of the center of gravity of a region where the concentration is above a certain level.

The absorption wavelength λON and the non-absorption wavelength λOF
Although F and the infrared rays having the distance measurement wavelength λL are separately emitted and received, if the output from the light receiving element 30 is discriminated according to the wavelength, it can be emitted and received at the same time.
Further, the non-absorption wavelength λOFF and the distance measurement wavelength λL can be made common. In the case of common use, the distance is also measured at the timing of receiving the non-absorbed infrared rays from the maximum density position.

Although hydrocarbon leakage is detected in the embodiments described above, the present invention can be applied to leakage detection of various gases if the absorption wavelength is selected according to the gas to be detected. You can

[0023]

As described above, according to the present invention, visualization is performed by utilizing the property that gas absorbs infrared rays having a specific wavelength, and the concentration becomes maximum in the distribution state of leakage concentration of the visualized gas. It is possible to calculate the distance to a position where there is a high possibility that leakage has occurred, by irradiating the area including the position in the space corresponding to the position with the ranging infrared light having a wavelength that is not absorbed by the gas. Since it is possible to obtain an image of the leak location and the distance, even if the leak location such as the ceiling is visualized from the opening for inspection, the position of the leak location can be accurately determined based on the distance, and the ceiling can be hung. You can improve the accuracy of the, and to minimize the amount of flapping and reduce the repair cost.

Further, it is possible to irradiate the leaking area with the distance measuring infrared ray and measure the distance to the leaking area by utilizing the luminous flux expanding means for expanding the irradiation of the absorption infrared ray and the non-absorption infrared ray.

Further, according to the present invention, since the absorption infrared ray and the non-absorption infrared ray and the distance measuring infrared ray are commonly received by the light receiving means, the structure of the apparatus is simplified and the non-absorption infrared ray and the distance measuring infrared ray are commonly used. This makes it possible to reduce the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a gas leakage visualization and distance measuring device 1 according to an embodiment of the present invention.

2 is a simplified cross-sectional view of the vicinity of the ceiling showing a gas leakage visualization and use state of the distance measuring device 1 of FIG. 1. FIG.

FIG. 3 is a diagram showing a principle of visualizing methane 3 which is a main component of the gas leakage visualization and distance measuring apparatus 1 of FIG. 1 when a gas leaks.

FIG. 4 is a diagram showing an image in which the leakage state of methane 3 is visualized by the gas leakage visualization and range finding device 1 of FIG.

5 is a flowchart showing an operating procedure of the gas leakage visualization and distance measuring device 1 of FIG.

[Explanation of symbols]

1 Gas leak visualization and ranging device 2 gas piping 3 hydrocarbons 4 Infrared for visualization 5 Infrared for distance measurement 6 light emitting part 8 Light receiving part 9 Visualization screen 10 Leakage status image 11 gas piping image 12 distance display 20 laser light source 21 Laser for leak detection 30 light receiving element 32 image processing circuit 33 Distance measuring circuit 40 ceiling plate 41 Inspection door 42 Repair points

   ─────────────────────────────────────────────────── ─── Continued front page    (71) Applicant 000196680             Seibu Gas Co., Ltd.             1-1-17 Chiyo, Hakata-ku, Fukuoka City, Fukuoka Prefecture (71) Applicant 593185544             Japan Gas Association             1-15-12 Toranomon, Minato-ku, Tokyo (72) Inventor Satoshi Takagi             4-1-2 Hirano-cho, Chuo-ku, Osaka-shi, Osaka Prefecture               Within Osaka Gas Co., Ltd. (72) Inventor Keishi Kawaguchi             4-1-2 Hirano-cho, Chuo-ku, Osaka-shi, Osaka Prefecture               Within Osaka Gas Co., Ltd. (72) Inventor Masayuki Tamura             1-5-20 Kaigan-dori, Minato-ku, Tokyo Tokyo tile             Within the corporation (72) Inventor Kenji Suyama             1-5-20 Kaigan-dori, Minato-ku, Tokyo Tokyo tile             Within the corporation (72) Inventor Hiroshi Ishida             2 Toho Gas, 507 Shinhorocho, Tokai City, Aichi Prefecture             Within the corporation F term (reference) 2G059 AA01 BB01 CC13 EE02 EE11                       FF08 GG01 GG03 HH01 KK01                       MM01 MM05 PP04                 2G067 AA11 AA14 BB15 BB17 CC04                       EE08 EE09

Claims (2)

[Claims] 1. A space having a possibility of gas leakage is irradiated with an absorption infrared ray having a wavelength that is absorbed by a gas to be visualized and a non-absorption infrared ray having a wavelength that is not absorbed by the gas, and the space is exposed. The absorption infrared rays and the non-absorption infrared rays that have passed through and are reflected are received, and image processing is performed to calculate the distribution state of the leakage concentration of the gas based on the ratio of the amount of received light of the absorption infrared rays and the non-absorption infrared rays, and the leakage concentration The distribution of
The visualization means for visualizing the leak state in the image of the space, and the absorption by the gas in a region including the position in the space corresponding to the position where the concentration becomes maximum in the distribution state of the leak concentration visualized by the visualization means. Gas leakage visualization and distance measurement, including distance measurement means for irradiating a distance measurement infrared ray having a wavelength that is not controlled, receiving the distance measurement infrared ray reflected from the area, and calculating a distance to the area. apparatus. 2. The gas leakage visualization and distance measuring device according to claim 1, further comprising a light receiving unit that commonly receives the absorbed infrared light, the non-absorbed infrared light, and the distance measuring infrared light.