JP3725832B2 - Gas leak location indicator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas leakage point indicating device capable of detecting and indicating a gas leakage point of a hydrocarbon compound.
[0002]
[Prior art]
Conventionally, since city gas has been mainly composed of methane, which is a hydrocarbon compound, whether or not it is leaking is determined by detecting the hydrocarbon concentration. In addition, since all the natural components of city gas including methane are odorless, a specific odor is added so that leakage can be seen even by human odor. 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 is disconnected, the cause can be easily determined by the city gas user and the leak can be stopped. When there is a leak from a high-pipe, etc., it is necessary to work at a high place with a scaffold or the like to repair the leak.
[0003]
[Problems to be solved by the invention]
City gas is colorless and transparent, and even when leakage occurs, it is generally a very small amount, so it is difficult to determine the leakage location. When there is a leak from high-altitude piping, it is necessary to build a scaffold and perform high-altitude work. Furthermore, since it is a dangerous work, a quick work is required. However, if you do not actually perform the height work with the scaffolding, you will not know the leak location, so invest a great deal of effort, build the scaffolding over a wide area, and work at the height on the scaffolding We work on fixing and repairing the leak location.
[0004]
An object of the present invention is to provide a gas leakage point indicating device that can directly indicate a gas leakage point even from a remote position.
[0005]
[Means for Solving the Problems]
The present invention irradiates a space where there is a possibility of gas leakage with an absorption infrared ray having a wavelength that is absorbed by the gas to be detected and a non-absorption infrared ray having a wavelength that is not absorbed by the gas, and passes through the space. A concentration distribution calculating unit that receives the absorbed infrared rays and the non-absorbed infrared rays reflected by the light source and performs a calculation process for calculating a distribution state of the leakage concentration of the gas based on a ratio of the received light amounts of the absorbed infrared rays and the non-absorbed infrared rays; ,
Visible light irradiating means for irradiating visible light for labeling at a position in the space corresponding to the position where the density is maximum in the distribution state of the leakage density calculated by the density distribution calculating means It is a gas leak location indicating device.
[0006]
According to the present invention, the gas leakage point indicating device includes a concentration distribution calculating unit and a visible light irradiation unit. The concentration distribution calculating means irradiates a space where there is a possibility of gas leakage with an absorption infrared ray having a wavelength that is absorbed by the gas to be detected and a non-absorption infrared ray having a wavelength that is not absorbed by the gas. Absorption infrared rays and non-absorption infrared rays that have passed through and reflected are received, and calculation 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 between the absorption infrared rays and the non-absorption infrared rays. The visible light irradiating means irradiates the visible light for the label to a position in the space corresponding to the position where the density is maximum in the leakage density distribution state calculated by the density distribution calculating means. When the gas leaks, the concentration is high at the leaked portion, and when the gas is separated from the leaked portion, the gas diffuses and the concentration becomes low. Therefore, there is a high possibility that the position where the concentration is the highest in the distribution of leakage concentration is the location where the gas leaks or is in the immediate vicinity, and the position in the space corresponding to the position where the concentration is maximum in the distribution of leakage concentration is marked. If the visible light is irradiated, visible light hits the leaked part of the pipe and the like, and it is possible to instruct the leaked part that is easily understood from a remote position. Since it is possible to optically indicate the location of gas leakage from a remote location, even if there is a leak in a high-level piping, the location of the leakage is accurately indicated before assembling the scaffolding, and quick repair work is performed. Can be performed efficiently.
[0007]
The concentration distribution calculating means includes
A width expansion means for expanding the width of the absorption infrared ray and the non-absorption infrared ray so that a measurement surface spreads;
The visible light irradiating means has the leakage density maximum position on the basis of the timing when the width expanding means irradiates the light beam at the position where the leakage density becomes maximum and the leakage density maximum position in the plane. It can also be configured to emit visible light.
[0008]
According to this configuration, the concentration distribution calculating unit that performs the calculation process of calculating the distribution state of the leakage concentration of the gas based on the ratio of the amount of received light between the absorbing infrared rays and the non-absorbing infrared rays includes the width expanding unit. Since the width expanding means expands the width of the absorbing infrared rays and the non-absorbing infrared rays so as to form a pyramidal light beam, it is possible to irradiate the infrared rays whose ends are flattened with respect to the space. The visible light irradiating means irradiates visible light at the maximum leakage density position based on the timing when the width expanding means irradiates the light flux to the place including the position where the leakage density is maximum and the maximum leakage density position. Visible light hits a leaking location at or near the leak concentration maximum position, and the indication of the leaking location can be easily performed from a remote location.
[0009]
Further, in the present invention, the density distribution calculating means performs image processing for superimposing the leakage density distribution on the image of the space as a calculation process for calculating the distribution state of the leakage density,
The visible light irradiation means searches for an object closest to the position where the density is maximum as a position in the space corresponding to the position where the density is maximum based on the result of image processing by the density distribution calculation means. The object to be searched is irradiated with the visible light.
[0010]
According to the present invention, the concentration distribution calculating means performs image processing for superimposing the leakage concentration distribution on the image of the space as the calculation process for calculating the distribution state of the gas leakage concentration, and the visible light irradiation means calculates the concentration distribution. Based on the result of the image processing by the means, the object closest to the position where the concentration is maximum is searched as the position in the space corresponding to the position where the gas leakage concentration is maximum, and is visible to the searched object. Since the light is irradiated, visible light hits the searched object and can be designated as a leaked portion.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a schematic configuration of a gas leak location indicating device 1 according to an embodiment of the present invention. The gas leak location indicating device 1 of the present embodiment visualizes the hydrocarbon 3 that is the main component of the gas leaking from the gas pipe 2 as an image corresponding to the leak concentration. The region where the hydrocarbon 3 is highly likely to leak is irradiated with the absorbing infrared ray 4 and the non-absorbing infrared ray 5 from the light emitting unit 6. Absorbing infrared rays 4 and non-absorbing infrared rays 5 themselves cannot be directly detected by human vision. Irradiated absorbed infrared rays 4 and non-absorbed infrared rays 5 pass through a region where hydrocarbon 3 leaks, and are reflected by the surface such as wall 7 to reach light receiving portion 8. The light receiving unit 8 includes a visualization screen 9, a leakage state image 10 of methane 3 that is obtained based on a ratio of received light intensity of the absorbed infrared rays 4 and the non-absorbed infrared rays 5, and a gas pipe image 11 that is a source of leakage. Can be displayed.
[0012]
The light emitting unit 6 includes a laser light source 20 and generates infrared laser beams having a plurality of wavelengths. The laser light source 20 includes a leak detection laser 21, a half mirror 22, a display alignment mechanism 23, and the like. The leakage detection laser 21 oscillates laser light having a plurality of wavelengths. Further, the leakage detection laser 21 generates an absorption infrared ray 4 having a wavelength λON that is absorbed by the hydrocarbon 3 and a non-absorption infrared ray 5 having a wavelength λOFF that is not absorbed by the hydrocarbon 3. Further, visible light for marking that indicates a leaking location is also generated by the visible light laser 24 for position display.
[0013]
The light receiving unit 8 includes a light receiving element 30 and a processing circuit 31 together with the visualization screen 9. The light receiving element 30 is formed by arranging minute light receiving cells in a planar shape. The processing circuit 31 includes an image processing circuit 32 and a leakage position calculation circuit 33. The image processing circuit 32 performs arithmetic processing on the electric signal generated by the light receiving element 30 based on light reception, and generates an image corresponding to the leakage density displayed on the visualization screen 9. The leak position calculation circuit 33 obtains the position of a leak point assumed in the gas pipe 2 or the like in the vicinity of the high concentration region of the hydrocarbon 3, and the light beam alignment means such as the display alignment mechanism 23 absorbs the infrared ray 4 at the leak position. The visible light 35 is irradiated from the visible light laser 24 for position display at the timing when the non-absorbing infrared ray 5 is irradiated. The visible light laser 24 for position display can change the irradiation direction of the visible light 35 with respect to the direction in which the display alignment mechanism 23 widens. Control is performed so as to change the irradiation direction of the visible light laser 24 for position display so that the visible light 35 strikes the position calculated as the leakage position by the leakage position calculation circuit 33. As a result, the visible light 35 is emitted from the display alignment mechanism 23 toward the leakage location 37, and an instruction can be given by illuminating the leakage location 37 in a spot shape.
[0014]
In addition, the distance to the leak location 37 can also be calculated | required using the visible light 35, the non-absorbing infrared rays 5, or the infrared rays and light of another wavelength. When the distance can be obtained, for example, the leakage state 37 is obtained by visualizing the leakage state from the opening such as the inspection port for the gas pipe 2 laid on the back of the ceiling, and the ceiling is obtained based on the obtained distance. The range to be removed can be determined by exposing the portion of the gas pipe 2 where the leaking portion 37 is generated, and the visible portion 35 can be instructed by applying the visible light 35 to the leaking portion 37 again.
[0015]
FIG. 2 shows a typical use state of the gas leak location indicating device 1 of the present embodiment. When the gas pipe 2 in which the hydrocarbon 3 has leaked is laid at a high place, the gas pipe 2 is examined on the visualization screen 9 in FIG. Look for the area that is occurring. When an area where leakage occurs is displayed on the visualization screen 9, the leakage position calculation circuit 33 in FIG. 1 calculates the leakage position, outputs visible light 35 from the position-displaying visible light laser 24, and leaks 37 Can be instructed. For example, since the leak location 37 can be instructed to the gas pipe 2 at a high place before assembling the scaffold from above the floor below, the range for assembling the scaffold can be narrowed, and repair work can be performed quickly. Can get started.
[0016]
FIG. 3 shows the principle of visualizing the hydrocarbon 3 which is the main component at the time of gas leakage in the gas leakage point indicating device 1 of the present embodiment. The hydrocarbon 3 has a property of absorbing infrared rays having a specific wavelength (frequency). The light emitting unit 6 irradiates an absorption infrared ray 4 having a wavelength λON absorbed by the hydrocarbon 3 and a non-absorption infrared ray 5 having a wavelength λOFF that is not absorbed by the hydrocarbon 3. The irradiated infrared rays are reflected by the wall 7 or the ground, and can be received by the light receiving unit 8. If the received light output from the light receiving element 30 that receives the two received wavelengths λON and λOFF is compared, and the absorbed infrared ray 4 is reduced compared to the non-absorbed infrared ray 5, hydrocarbons 3 are present. I understand. Further, the amount of decrease in the received light output is proportional to the concentration of the hydrocarbon 3.
[0017]
It is known that the wavelength λON of the absorbed infrared rays 4 for hydrocarbons 3 for example methane is 3.3 μm. A non-absorbing infrared ray 5 having a wavelength λOFF different from the wavelength λON is also generated from the leakage detection laser 21 shown in FIG. 1, and a two-wavelength infrared laser beam is applied to a space including an object such as the gas pipe 2, and the wall 7 Receives reflected light from the ground. When the hydrocarbon 3 exists in the range of the space irradiated with the two-wavelength infrared laser light, the received light intensity at the hydrocarbon absorption wavelength λON is lower than the received light intensity at the non-absorption wavelength λOFF. 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, for example, by testing and confirming the concentration at which leakage can be detected in advance.
[0018]
In order to obtain a leakage state image 10 as shown in FIG. 1, first, an infrared laser beam spreading in a pyramid shape is irradiated, and reflected light is reflected by a light receiving element 30 in which light receiving cells are arranged in a planar shape, a linear shape, or a dot shape. Detect. Thereby, the hydrocarbon concentration distribution on the line detected by the light receiving element 30 can be measured. Next, the concentration distribution of the hydrocarbon 3 in the vicinity of the object can be measured in a planar shape by receiving light in the direction of spreading in a pyramid shape with respect to the infrared laser irradiation site. By performing image processing by the image processing circuit 32 based on this density distribution, it is possible to visualize the leakage state image 10.
[0019]
FIG. 4 shows an image in which the leakage state of the hydrocarbon 3 is visualized by the gas leakage device 1 of the present embodiment. The gas leakage 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 in FIG. 1 are added as adapters. An apparatus having a detection sensitivity of 10 ppm for methane and a detection distance of 5 m can be formed in a weight of 5 kg. The absorbing infrared rays 4 and the non-absorbing infrared rays 5 are generated as beams extending in a pyramid shape, and a planar visualization image can be obtained.
[0020]
FIG. 5 shows a procedure for operating the gas leak location indicating apparatus 1 of the present embodiment and instructing a hydrocarbon leak location. In step s0, the power is turned on and turned on, and the warm-up operation is performed. Then, in step s1, the infrared ray 4 having the wavelength λON is output from the laser light source 20 in FIG. In step s2, the absorbed infrared ray 4 is received. In step s3, the laser light source 20 outputs the non-absorbing infrared ray 5 having the wavelength λOFF. In step s4, the non-absorbing infrared ray 5 is received. In step s5, light from the background is received.
[0021]
In step s6, difference processing is performed on the image of the absorption wavelength λON and the non-absorption wavelength λOFF received in steps s2 and s4, and the difference image is superimposed on the image of the non-absorption wavelength λOFF. In addition to the images of the absorption wavelength λON and the non-absorption wavelength λOFF, background light is received in step s5, and noise can be reduced. Since the obtained image represents the leakage concentration of hydrocarbons, the position at which the leakage amount is maximum is calculated and obtained. The position where the leakage amount is maximum can also be obtained as the position of the center of gravity of an area where the density is a certain level or more.
[0022]
In step s7, the leakage position in the actual space is calculated based on the leakage position information in the image obtained in step s6, and the direction and timing of irradiating visible light from the position display visible light laser 24 are controlled. . In step s8, when the predetermined timing comes, laser output of visible light 35 is performed from the position-displaying visible light laser 24, and the leakage location 37 can be instructed. After step s8, the process returns to step s1, and thereafter steps s1 to s8 are repeated.
[0023]
The infrared rays having the absorption wavelength λON and the non-absorption wavelength λOFF are separately irradiated and received. However, if the output from the light receiving element 30 is discriminated according to the wavelength, it can be simultaneously irradiated and received. In addition, the visible light 35 for indicating the leak location is arranged geometrically by the leak position calculation circuit 33 from a light source attached to the outside of the casing of the gas leak location indicating device 1 independently of the laser light source 20, for example. It can also be generated in the direction obtained by calculation based on. Further, the calculation of the leakage concentration of methane and the calculation of the position where the maximum concentration can be performed by the image processing circuit 32 can be performed without necessarily displaying the leakage state on the visualization screen 9. It is also possible to give only instructions.
[0024]
In the embodiment described above, although leakage detection of hydrocarbons that are the main components of gas is performed, if the absorption wavelength is selected according to the gas to be detected, hydrocarbons other than the main component methane of city gas For example, the present invention can be similarly applied to propane, which is often used as gas fuel in a cylinder. Furthermore, if wavelengths other than infrared rays are selected according to gas, this invention is applicable to the detection of various gas leaks.
[0025]
【The invention's effect】
As described above, according to the present invention, since the concentration is high at the leaked portion of the gas, and the gas diffuses and decreases in concentration when leaving the leaked portion, the space corresponding to the position where the concentration is maximized in the distribution of the leaked concentration. If visible light for marking is irradiated to the inside position, visible light hits a leaked portion of a pipe and the like, and it is possible to give an indication of a leaked portion that can be easily understood from a remote location.
[0026]
Further, the distribution of the leakage concentration of the gas including the leaked portion can be obtained by expanding the absorbing infrared rays and the non-absorbing infrared rays so as to form a pyramidal light beam. Visible light is irradiated based on the timing when the light beam is irradiated in the direction including the position where the leakage density becomes maximum and the leakage density maximum position in the width direction. Visible light hits the leaked part, and the instruction of the leaked part can be easily performed from a remote location.
[0027]
Further, according to the present invention, based on the result of the image processing that superimposes the leakage density distribution on the image of the space, the object closest to the position where the density is maximum is searched, and the object to be searched is irradiated with visible light. Therefore, visible light hits the searched object, and can be designated as a leaked portion.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a gas leak location indicating device 1 according to an embodiment of the present invention.
FIG. 2 is a simplified perspective view showing a use state of the gas leak location indicating device 1 of FIG. 1;
3 is a diagram showing the principle of visualizing hydrocarbon 3 as a main component when gas leaks in the gas leak location indicating device 1 of FIG. 1; FIG.
4 is a diagram showing an image of visualizing the leakage state of hydrocarbon 3 in the gas leakage visualization and ranging device 1 of FIG.
FIG. 5 is a flowchart showing an operation procedure of the gas leak location indicating device 1 of FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas leak location indication apparatus 2 Gas piping 3 Hydrocarbon 4 Absorbing infrared rays 5 Non-absorbing infrared rays 6 Light emission part 8 Light receiving part 9 Visualization screen 10 Leakage state image 11 Gas piping image 20 Laser light source 21 Leak detection laser 23 Display alignment mechanism 24 Visible light laser 30 for position display Light receiving element 32 Image processing circuit 33 Leakage position calculation circuit 35 Visible light 37 Leakage location

Claims (2)

Irradiated infrared rays having a wavelength that is absorbed by the gas to be detected and non-absorbing infrared rays having a wavelength that is not absorbed by the gas to a space where there is a possibility of gas leakage, and reflected through the space. A concentration distribution calculating means for receiving absorption infrared rays and non-absorbing infrared rays, and performing calculation processing for calculating a distribution state of leakage concentration of the gas based on a ratio of received light amounts of the absorbing infrared rays and the non-absorbing infrared rays;
Visible light irradiating means for irradiating visible light for labeling at a position in the space corresponding to the position where the density is maximum in the distribution state of the leakage density calculated by the density distribution calculating means Gas leak location indicator. The density distribution calculating means performs image processing for superimposing the leakage density distribution on the image of the space as a calculation process for calculating the distribution state of the leakage density,
The visible light irradiation means searches for an object closest to the position where the density is maximum as a position in the space corresponding to the position where the density is maximum, based on the result of image processing by the density distribution calculation means. The gas leak location indicating device according to claim 1, wherein the visible light is irradiated to an object to be searched.

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