JP5936529B2 - Gas leak detection system - Google Patents

Description

  The present invention relates to a gas leak detection system that detects a leak region of a gas having an infrared absorption spectrum at a specific wavelength, such as LNG (Liquefied Natural Gas), LPG (Liquefied Petroleum Gas), and methane.

  Accurately identify where flammable gas leaks in facilities and equipment that may generate or discharge flammable gases such as LNG, LPG, methane, etc. in a wide range of outdoor storage areas such as natural gas plants and natural gas pipelines It was difficult to specify. As a conventional technique for specifying the position of gas leakage in such a wide storage target area, Patent Document 1 discloses that the light source is turned and a plurality of sensors having photodiodes are arranged in the circumferential direction to determine the direction of the leakage point. A gas concentration monitoring system to be identified is disclosed. In this system, the wind direction measurement value measured by the anemometer and the estimated gas ejection range of the gas concentration calculated based on the wind speed measurement value are calculated, and the abnormalities in the atmosphere are calculated based on the influence of the weather such as wind. The position where gas or combustible gas leaks can be specified accurately.

JP 2008-116263 A

  As a conventional gas leak detection sensor, it is necessary to detect a leak between a point detection sensor and a combination of a light source and a light reception sensor that detect and measure the resistance change of the resistor due to the combustion heat on the catalyst. There is a line detection sensor that is disposed at a location and detects leakage between the light source and the light receiving sensor. However, since the point detection sensor is a fixed type that is arranged at each point that requires leakage detection, it is difficult to specify the leakage point. In the line detection sensor, the leakage point exists between the light source and the light receiving sensor. Even if it is understood, it is not possible to identify any more leak points.

  The system disclosed in Patent Document 1 applies a line detection sensor that uses a semiconductor laser element as a light source and a photodiode as a light receiving sensor, and provides a plurality of light receiving sensors in the circumferential direction of a turning light source, and the direction of a leakage point. Is to identify. However, in this system, although it is possible to specify the direction of the gas leakage point from the light source in a wide outdoor storage target area, it is necessary to perform line detection between the rotating light source and each sensor, and a wide inspection target area. The gas leaks in were not able to be detected simultaneously by each sensor. That is, since it takes time to detect a gas leak in a wide area to be inspected, it is not possible to efficiently identify a gas leak area where a gas leak has occurred.

  The present invention has been made in view of the above-mentioned problems of the conventional gas leak detection system, and is a new and improved gas leak capable of more efficiently specifying a gas leak region in a wide area to be inspected. The purpose is to provide a detection system.

One aspect of the present invention is a gas leakage detection system for detecting a gas leakage in an inspection target region having an obstacle that reflects a laser beam, the laser beam having an absorption wavelength specific to the gas oscillated from a light source. A light source device that irradiates diffused diffused laser light; and a light receiving sensor that receives reflected light of the diffused laser light that is provided at a position where the length of the optical path to the light source device is a predetermined value and is reflected by the obstacle; A leakage determination unit that determines the presence or absence of leakage of the gas from the absorption wavelength of reflected light received by the light receiving sensor after the irradiation with the diffused laser light, and at least after the leakage determination unit detects the leakage of the gas A leakage region that specifies the gas leakage region by adjusting any one of the diffusion laser light emitted from the light source device, the detection direction of the light receiving sensor, and the detection range of the light receiving sensor. And a specific portion, the features the detection range changing unit for changing the range for detecting the reflected light of the light receiving sensor is further the leakage area specifying unit, after the leakage determination unit detects the leakage of the gas, wherein by detection range changing unit controls to change the detection range of the light receiving sensor, related to the gas leakage detection system characterized that you identify the leakage area of the gas.

  According to one aspect of the present invention, after the laser beam from the light source is diffused and the spot diameter is enlarged and reflected, the reflected light from the obstacle is received by the detection sensor. The leakage area in the irradiation area can be identified efficiently in a short time.

  In this case, according to an aspect of the present invention, the laser light switching unit that switches the laser light oscillated from the light source of the light source device from the diffused laser light to collimated light is further provided, and the leakage region specifying unit includes the leakage light After the determination unit detects the gas leakage, the laser light switching unit controls the diffusion laser light emitted from the light source device to switch to the collimated light, thereby identifying the gas leakage region. It is good.

  In this way, since the diffused laser light emitted from the light source device is switched to collimated light after the leakage determination unit detects gas leakage, it is possible to easily narrow down when scanning the gas leakage region.

Moreover, in one aspect of the present invention, a detection range changing unit that changes a range in which the reflected light of the light receiving sensor is detected is further provided, and the leakage region specifying unit detects the leakage of the gas by the leakage determination unit. later, by the detection range changing unit controls to change the detection range of the light receiving sensor, that identifies the leakage area of the gas.

  In this way, since the detection direction of the light receiving sensor is changed after the leakage determination unit detects the gas leakage, it is possible to easily narrow down when detecting the gas leakage region.

  Moreover, in one aspect of the present invention, a plurality of the light receiving sensors are provided in parallel, the detection ranges of the respective light receiving sensors are different from each other, and the leak region specifying unit is configured to detect the leak of the gas after the leak determination unit detects the leak of the gas. The gas leak region may be specified based on the inspection result of whether any one of the light receiving sensors detects gas leak.

  In this way, since the detection ranges of the respective light receiving sensors are separated, it is easy to identify the gas leakage region based on the detection result of any of the light receiving sensors after the leakage determination unit detects gas leakage. Yes.

  In the aspect of the invention, the light source device may further include a diffusion angle adjustment unit that adjusts an irradiation angle of the diffusion laser light in a stepwise manner, and the leakage determination unit may be configured such that the leakage determination unit has the gas leakage. After the detection, the gas diffusion region may be specified by controlling the diffusion angle adjusting unit to adjust the irradiation angle of the diffusion laser light stepwise.

  In this way, the leakage determination unit adjusts the irradiation angle of the diffusion laser light emitted from the light source device after detecting the gas leakage step by step, so that the gas leakage region within the irradiation region of the diffusion laser light is narrowed down. Can be done easily.

  Moreover, in one aspect of the present invention, an alarm device that issues an alarm may be further provided when the leakage determination unit determines that the gas has leaked after irradiation with the diffusion laser light.

  In this way, since the alarm is sent from the alarm device after the leak determination unit detects the gas leak, it informs the monitoring personnel in the central control room, etc. that the gas leak has occurred. As a result, a quick response to gas leakage is possible.

  According to another aspect of the present invention, there is provided a gas leak detection system for detecting a gas leak in a region to be inspected having a plurality of obstacles that reflect laser light, wherein the absorption wavelength specific to the gas oscillated from a light source And a light source device that irradiates a diffused laser beam obtained by diffusing the laser beam and an obstacle within the irradiation range of the diffused laser beam are provided at positions where the length of the optical path to the light source device is a prescribed value. A light receiving sensor that receives the diffused laser light; a leak determining unit that determines the presence or absence of leakage of the gas from an absorption wavelength of reflected light received by the light receiving sensor after irradiating the diffused laser light; and the leak determining unit The gas leak detection system is characterized in that after the gas leak is detected, the gas leak region is specified based on an inspection result as to whether any of the light receiving sensors detects the gas leak. Related to.

  According to another aspect of the present invention, since the detection range of each light receiving sensor is separately divided after the diffusion laser light is simultaneously oscillated toward each light receiving sensor, the leak determination unit detects a gas leak. Based on the detection result of any one of the light receiving sensors, the gas leakage region can be easily identified.

  At this time, according to an aspect of the present invention, an alarm device that issues an alarm may be further provided when the leakage determination unit determines that the gas has leaked after irradiation with the diffusion laser light.

  In this way, since the alarm is sent from the alarm device after the leak determination unit detects the gas leak, it informs the monitoring personnel in the central control room, etc. that the gas leak has occurred. As a result, a quick response to gas leakage is possible.

  As described above, according to the present invention, after the laser beam from the light source is diffused and the spot diameter is expanded to irradiate the region to be inspected, the reflected light from the obstacle is received by the detection sensor. It is possible to efficiently identify a leakage area within a wide irradiation area between obstacles in a short time.

1 is a schematic configuration diagram of a gas leak detection system according to a first embodiment of the present invention. It is a schematic block diagram of the light source device which concerns on this invention. It is a schematic block diagram of the light receiving sensor which concerns on this invention. It is a flowchart which shows the basic flow of the gas leak detection in the gas leak detection system which concerns on this embodiment. It is a flowchart of the gas leak area | region identification process by the gas leak detection system which concerns on this embodiment. It is operation | movement explanatory drawing of the gas leak area | region identification process by the gas leak detection system which concerns on this embodiment. It is operation | movement explanatory drawing of the gas leak area | region identification process by the gas leak detection system which concerns on this embodiment. It is a flowchart of the gas leak area | region identification process by the gas leak detection system which concerns on the 2nd Embodiment of this invention. It is operation | movement explanatory drawing of the gas leak area | region identification process by the gas leak detection system which concerns on this embodiment. It is operation | movement explanatory drawing of the gas leak area | region identification process by the gas leak detection system which concerns on this embodiment. It is operation | movement explanatory drawing of the gas leak area | region identification process by the gas leak detection system which concerns on the 3rd Embodiment of this invention. It is a flowchart of the gas leak area | region identification process by the gas leak detection system which concerns on the 4th Embodiment of this invention. It is explanatory drawing which shows an example of the mechanism part which adjusts the irradiation angle of the light source device of the gas leak detection system which concerns on this embodiment. It is operation | movement explanatory drawing of the gas leak area | region identification process by the gas leak detection system which concerns on this embodiment. It is operation | movement explanatory drawing of the gas leak area | region identification process by the gas leak detection system which concerns on the 5th Embodiment of this invention. It is a flowchart of the gas leak detection by the gas leak detection system which concerns on the 6th Embodiment of this invention. It is operation | movement explanatory drawing of the gas leak detection by the gas leak detection system which concerns on this embodiment. It is a flowchart of the operation | movement of the gas leak detection by the gas leak detection system which concerns on the 7th Embodiment of this invention. It is operation | movement explanatory drawing of the gas leak detection by the gas leak detection system which concerns on this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are essential as means for solving the present invention. Not necessarily.

(First embodiment)
First, a first embodiment of the gas leakage detection system of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a gas leakage detection system according to the present embodiment, FIG. 2 is a schematic configuration diagram of a light source device according to the present invention, and FIG. 3 is a schematic configuration of a light receiving sensor according to the present invention. FIG.

  As shown in FIG. 1, the gas leak detection system 100 of the present embodiment includes a light source device 10, a light receiving sensor 20, a measurement unit 40, an AD converter 50, a central control device 102, a display unit 60, And a storage unit 70. The present embodiment is characterized in that a detection sensor receives light reflected from an obstacle after diffusing laser light from a light source to expand a spot diameter and irradiating the region to be inspected.

  The light source device 10 collimates and irradiates laser light. In this embodiment, as shown in FIG. 2, the light source device 10 includes an LD module 11, mirrors 12a, 12b, and 12c, a concave optical system 13, a convex optical system 14, a reference cell 15, and a reference photodiode. 16.

  The LD module 11 is a light source that oscillates at least a laser beam having an absorption wavelength specific to a gas to be measured and inspected. For example, the LD module 11 includes a semiconductor laser element, a Peltier element for adjusting the temperature of the semiconductor laser element, and the like. . The light source is not limited to this semiconductor laser element, but can be applied to all other laser oscillators capable of wavelength modulation, and wavelength modulation is also possible for light and electromagnetic waves other than lasers. All cases are applicable.

  The mirror 12 a reflects the laser light oscillated from the LD module 11. The half mirror 12b reflects a part of the laser beam reflected by the mirror 12a toward the optical systems 13 and 14 and transmits a part thereof. The mirror 12c reflects the laser light transmitted through the half mirror 12b toward the reference cell 15.

  The concave optical system 13 is a concave lens that diffuses laser light oscillated from the light source 11. The convex optical system 14 is a convex lens that collimates the laser light diffused by the concave optical system 13, and is provided on the irradiation light side from the concave optical system 13 when irradiating the collimated laser light. Since the light source device 10 of the present embodiment normally transmits the laser light from the light source 11 only through the concave optical system 13, it is irradiated with diffused laser light, and the convex optical system 14 is connected to the concave optical system 13 when necessary. Since it is provided on the irradiation light side, the irradiation light can be appropriately switched as necessary.

  The reference cell 15 has a predetermined reference cell length Lo, and methane CH4, which is a measurement target, is enclosed in the reference cell 15 at a predetermined gas concentration Co. The reference gas concentration measurement value Do detected by the reference photodiode 16 is input to the measurement unit 40 and used for gas concentration verification and wavelength stabilization. The reference photodiode 16 receives the laser light transmitted through the reference cell 15 and sends an electrical signal based on the laser light to the measurement unit 40.

  The light receiving sensor 20 receives the reflected light reflected by the obstacle 30 included in the irradiation region of the diffused laser light L20 irradiated from the light source device 10. As shown in FIG. 3, the light receiving sensor 20 is provided with a measurement photodiode 21 and a background light photodiode 22. The measurement photodiode 21 is arranged on the optical axis of the reflected light of the obstacle 30 of the diffused laser light L20 and receives the reflected light of the obstacle 30 provided in the measurement area. The background light photodiode 22 is disposed at a position off the optical axis of the reflected light of the diffused laser light L20 and receives background light (background) in the measurement region. The measurement photodiode 21 and the background light photodiode 22 send the received reflected light and the electrical signal based on the background light to the measurement unit 40, and send the received light signal to the AD converter 50 via the measurement unit 40, respectively. So connected. The AD converter 50 is connected to a central control device 102, and the central control device 102 is connected to a display unit 60 having a display.

  The measurement unit 40 processes electrical signals from the reference photodiode 16 of the light source device 10, the measurement photodiode 21 of the light receiving sensor 20, and the background light photodiode 22, and converts the processed analog data into an AD converter 50. Send to. The AD converter 50 converts the analog data processed by the measurement unit 40 into digital data and sends the digital data to the central controller 102.

  The central control device 102 stores the data sent from the AD converter 50 in the storage unit 70 and displays the data converted into a numerical value or a graph on the display of the display unit 60. Further, the central controller 102 determines the difference between the intensity of the light received by the measurement photodiode 21 (diffused laser light reflected light + background light) and the intensity of the light received by the background light photodiode 22 (background light). Is obtained by calculation, and the presence or absence of gas leakage in the irradiation region of the diffused laser light to be the inspection target region is determined based on the calculation result.

  In the present embodiment, the central control apparatus 102 includes at least a leakage determination unit 106, a leakage region specifying unit 108, a laser light switching unit 110, a detection range changing unit 112, and a diffusion angle adjusting unit 114. Features.

  The leakage determination unit 106 determines the presence or absence of gas leakage from the absorption wavelength of the reflected light received by the light receiving sensor 20 after irradiating the diffused laser light L20. Specifically, the leakage determination unit 106 obtains the difference between the intensity of the light received by the measurement photodiode 21 and the intensity of the light received by the background light photodiode 22, and performs an inspection based on the calculation result. The presence or absence of gas leakage in the irradiation region of the diffusion laser beam L20 that is the target region is determined. Further, in the present embodiment, an alarm device 80 is further provided that issues an alarm when the leakage determination unit 106 determines that there is a gas leak after irradiation with the diffusion laser light.

  The leakage area specifying unit 108 detects at least one of the diffusion laser light L20 emitted from the light source device 10, the detection direction of the light receiving sensor 20, and the detection range of the light receiving sensor 20 after the leakage determination unit 106 detects gas leakage. By adjusting, the gas leakage area is specified. The identification of the gas leakage region by the system 100 of the present embodiment is mainly based on the adjustment of the diffusion laser light L20 from the optical device 10 by the laser light switching unit 110 or the diffusion angle adjustment unit 114, and the detection range changing unit 112. Is due to a change in the detection direction of the light receiving sensor 20.

  The laser light switching unit 110 switches the laser light L10 oscillated from the light source 11 of the light source device 10 from the diffused laser light L20 to the collimated light L30. In the present embodiment, when the leakage determination unit 106 determines that there is gas leakage, the laser beam switching unit 110 irradiates collimated light by providing the convex optical system 14 on the irradiation light side of the concave optical system 13. To control. Further, the laser light switching unit 110 retracts the convex optical system 14 from the irradiation light side of the concave optical system 13 when switching the irradiation light from the collimated light to the diffused laser light. The diffusion angle adjustment unit 114 adjusts the irradiation angle of the diffusion laser light L20 of the light source device 10 in a stepwise manner. The detection range changing unit 12 changes the range in which the reflected light of the light receiving sensor 20 is detected. The operation of specifying the gas leakage area by the central control device 102 will be described later.

  Next, the gas leak detection operation in the gas leak detection system according to the present embodiment will be described with reference to the drawings. FIG. 4 is a flowchart showing a basic flow of gas leak detection in the gas leak detection system according to the present embodiment.

  First, in the present embodiment, in order to detect gas leakage, irradiation light from a light source is diffused as measurement light and the spot diameter is expanded (step S10). Thereafter, the reflected light from the obstacle is received by the detection sensor (step S12), and the presence or absence of gas leakage is determined (step S14). If it is determined in step S14 that there is a gas leak, the process proceeds to a leak region specifying step. In this embodiment, since diffused laser light is irradiated as measurement light, the presence or absence of gas leakage within a wide irradiation area between the light source and the obstacle can be performed in a short time.

  Next, operation | movement of the gas leak area | region identification process by the gas leak detection system which concerns on this embodiment is demonstrated, using drawing. FIG. 5 is a flowchart of the gas leakage region specifying step by the gas leakage detection system according to the present embodiment, and FIG. 6 is an operation explanatory diagram of the gas leakage region specifying step by the gas leakage detection system according to the present embodiment. FIG. 7 is an operation explanatory diagram of a gas leakage region specifying step by the gas leakage detection system according to the present embodiment.

  The present embodiment is characterized in that the gas leakage region is specified by the control of the light source device 10 by the laser light switching unit 110. That is, the leakage region specifying unit 108 irradiates the diffusion laser light L20 and the leakage determination unit 106 detects gas leakage (step S16), and then the diffusion laser light irradiated from the light source device 10 by the laser light switching unit 110. Control is performed to switch L20 to collimated light L30 (step S21).

  At this time, the light source device 10 sets the measurement light irradiation point to the scanning start point (step S22), and then starts scanning the sensor monitoring area A10 as shown in FIG. 7 (step S23). When scanning in step S23, start from one of the scans in the X-axis direction and the Y-axis direction, and if the leak determination unit 106 detects that there is a gas leak (step S24), an alarm is issued from the alarm device 80. Transmitting (step S25).

  On the other hand, if the leakage determination unit 106 does not detect gas leakage in step S24, scanning in either the X-axis direction or the Y-axis direction ends (step S26), and whether or not the scanning of the sensor monitoring area A10 is completed. Is confirmed (step S27), and when the scanning is completed, the process proceeds to a leakage region specifying step (step S28). On the other hand, if the scanning of the sensor monitoring area A10 has not been completed, scanning of the scanning point in either the X-axis direction or the Y-axis direction is started, and the process returns to step S23 to perform the operation in the sensor monitoring area. Do.

  In this way, in the present embodiment, by switching the irradiation light from the diffused laser light L20 to the collimated light L30, the gas leakage area P10 is specified by narrowing down the gas leakage location. As described above, after the leakage determination unit 106 detects the gas leakage, the diffused laser light L20 emitted from the light source device 10 is switched to the collimated light L30. Therefore, it is possible to easily narrow down when scanning the gas leakage region P10. It becomes like this.

(Second Embodiment)
Next, operation | movement of the gas leak area | region identification process by the gas leak detection system which concerns on the 2nd Embodiment of this invention is demonstrated, using drawing. FIG. 8 is a flowchart of the gas leakage region specifying process by the gas leakage detection system according to the present embodiment, and FIG. 9 is an operation explanatory diagram of the gas leakage region specifying process by the gas leakage detection system according to the present embodiment. FIG. 10 is an operation explanatory diagram of a gas leakage region specifying step by the gas leakage detection system according to the present embodiment.

  The present embodiment is characterized in that the gas leakage region is specified by the control of the light receiving sensor 20 by the detection range changing unit 112. That is, after the leakage area specifying unit 108 irradiates the diffused laser light L20 and the leakage determination unit 106 detects gas leakage (step S16), the detection range changing unit 112 receives the light receiving sensor 20 as shown in FIG. The monitoring area R20 is controlled to be narrowed down to dots (step S31).

  At this time, the light receiving sensor 20 sets the monitoring point of the sensor as the scanning start point (step S32), and then starts scanning in the measurement light irradiation region B10 as shown in FIG. 10 (step S33). When scanning in step S33, start from one of the scans in the X-axis direction and the Y-axis direction, and if the leak determination unit 106 detects that there is a gas leak (step S34), an alarm is issued from the alarm device 80. Transmitting (step S35).

  On the other hand, if the leakage determination unit 106 does not detect gas leakage in step S34, scanning in either the X-axis direction or the Y-axis direction ends (step S36), and has the scanning of the measurement light irradiation region B10 been completed? Whether or not (step S37), when the scanning is completed, the process proceeds to a leakage area specifying step (step S38). On the other hand, when the scanning of the measurement light irradiation area B10 is not completed, the scanning point is started to scan in the other of the X axis direction and the Y axis direction, and the process returns to step S33 to enter the measurement light irradiation area. Perform the operation.

  In this way, in the present embodiment, the gas leakage area P10 is reduced by narrowing down the gas leakage area by changing the detection range of the light receiving sensor 20 so as to reduce the area from the surface area to the point area, for example. Identify. As described above, after the leakage determination unit 106 detects the gas leakage, the detection range of the light receiving sensor is changed from the surface region to the point region, so that it is possible to easily narrow down when detecting the gas leakage region P10. .

(Third embodiment)
Next, operation | movement of the gas leak area | region identification process by the gas leak detection system which concerns on the 3rd Embodiment of this invention is demonstrated, using drawing. FIG. 11 is an operation explanatory diagram of a gas leakage region specifying step by the gas leakage detection system according to the third embodiment of the present invention.

  In the present embodiment, as shown in FIG. 11, a plurality of light receiving sensors 20a, 20b, and 20c are provided on the position side of the light source device 10, and the light receiving sensors 20a, 20b, and 20c reduce the intensity of reflected light from the obstacle 30. By measuring, the presence or absence of gas leakage is detected. Further, since the prospective angles of the sensors 20a, 20b, and 20c are adjusted so that the entire laser irradiation area can be monitored, the detection ranges R1, R2, and R3 of the light receiving sensors 20a, 20b, and 20c are different from each other. Then, after the leak determination unit 106 detects the gas leak, the leak region specifying unit 108 detects the gas leak region based on the inspection result of which one of the light receiving sensors 20a, 20b, and 20c detects the gas leak. Is identified.

  In this way, when the leakage gas P10 exists in the monitoring regions R1, R2, and R3 of the light receiving sensors 20a, 20b, and 20c, reflected light to the light receiving sensors 20a, 20b, and 20c is absorbed by the light absorption of the leakage gas P10. Incident intensity decreases. By detecting the decrease in the incident intensity with the light receiving sensors 20a, 20b, and 20c, the presence or absence of gas leakage can be determined. In addition, since the detection ranges of the respective light receiving sensors are divided separately, the gas leakage area can be easily identified based on the detection result of any of the light receiving sensors after the leakage determination unit detects the gas leakage. That is, it is possible to specify the direction and the leakage scale of the gas leakage point P10 in a short time from the assigned monitoring areas R1, R2, and R3 of the light receiving sensors 20a, 20b, and 20c.

(Fourth embodiment)
Next, operation | movement of the gas leak area | region identification process by the gas leak detection system which concerns on the 4th Embodiment of this invention is demonstrated, using drawing. FIG. 12 is a flowchart of the gas leakage region specifying process by the gas leakage detection system according to the present embodiment, and FIG. 13 is an operation explanatory diagram of the gas leakage region specifying process by the gas leakage detection system according to the present embodiment. FIG. 14 is an explanatory diagram illustrating an example of a mechanism unit that adjusts the irradiation angle of the light source device of the gas leakage detection system according to the present embodiment.

  The present embodiment is characterized in that the gas leakage region is specified by the control of the light source device 10 by the diffusion angle adjusting unit 114. That is, the leakage area specifying unit 108 irradiates the diffusion laser light L20, and after the leakage determination unit 106 detects gas leakage (step S16), the diffusion angle adjustment unit 114 sets the laser spot diameter Ai to the maximum value A0. (Step S41). Thereafter, the diffusion angle adjustment unit 114 adjusts the irradiation angle of the diffusion laser light stepwise (step S43) so that the diffusion angle adjustment unit 114 reduces the laser spot diameter Ai stepwise from the maximum value A0 (step S42). ).

  Then, while the laser spot diameter Ai is gradually reduced, the leakage determination unit 106 determines the presence or absence of gas leakage, and when the gas leakage state is detected from “present” to “absent” (step S44). As shown in FIG. 13, it can be seen that the gas leakage region P10 is in the region between the laser spot diameters Ai-1 and Ai. On the other hand, if the leakage determination unit 106 does not detect gas leakage in step S44, the process returns to step S42ni, the laser spot diameter Ai is reduced to the laser spot diameter Ai + 1 which is reduced by one more stage, and the same operation flow is repeated. The laser spot diameter can be narrowed down by, for example, switching optics in which the concave optical system 13 of the optical apparatus 10 is provided with a plurality of concave optical systems 15-1 to 15-5 having different diffusion angles as shown in FIG. The diffusion angle may be changed using the system 15 while turning the central axis C10.

  Thus, in this embodiment, after the leakage determination unit 106 detects gas leakage, the irradiation angle of the diffusion laser light emitted from the light source device 10 is adjusted in stages, so that the irradiation region of the diffusion laser light is adjusted. It is possible to easily narrow down the gas leakage area. That is, since the gas leak region is narrowed by changing the spot diameter size of the diffused laser beam, it is possible to narrow the leak region by performing a wide range of measurements in a short time.

(Fifth embodiment)
Next, operation | movement of the gas leak area | region identification process by the gas leak detection system which concerns on the 5th Embodiment of this invention is demonstrated, using drawing. FIG. 15 is an operation explanatory diagram of a gas leak region specifying step by the gas leak detection system according to the fifth embodiment of the present invention.

  In the present embodiment, as shown in FIG. 15, the light receiving sensor 20-that receives the diffused laser light L20 on each of the obstacles 30-1, 30-2, and 30-3 within the irradiation range of the diffused laser light L20. 1, 20-2, and 20-3 are provided. The light receiving sensors 20-1, 20-2, and 20-3 are provided at positions where the length of the optical path to the light source device 10 is a specified value. By providing the sensors 20-1, 20-2, and 20-3 as described above, the irradiation light from the light source device 10 is diffused and irradiated, and received by a plurality of detection sensors installed in the irradiation area. And the leak detection in the optical path between the light source device 10 and each sensor 20-1, 20-2, 20-3 is performed.

  In this way, in the present embodiment, since the detection range of each light receiving sensor is separately divided after the diffusion laser light is simultaneously oscillated toward each light receiving sensor, the leakage determination unit 106 has detected a gas leak. The gas leakage region can be easily identified based on the detection result of any of the light receiving sensors 20-1, 20-2, and 20-3 later. That is, by installing a plurality of sensors 20-1, 20-2, 20-3 on obstacles 30-1, 30-2, 30-3 such as structures in the laser irradiation area, the presence or absence of gas leakage and leakage The direction of a point can be measured in a short time.

(Sixth embodiment)
Next, operation | movement of the gas leak area | region identification process by the gas leak detection system which concerns on the 6th Embodiment of this invention is demonstrated, using drawing. FIG. 16 is a flowchart of a gas leak region specifying process by the gas leak detection system according to this embodiment, and FIG. 17 is an operation explanatory diagram of the gas leak region specifying process by the gas leak detection system according to this embodiment.

  In the present embodiment, as shown in FIG. 17, the laser light emitted from the light source device 18 is not diffused laser light but collimated laser light, and the irradiation direction is set to any direction within the inspection target region. The irradiation direction adjustment part 19 which adjusts so that it may become is provided, It is characterized by the above-mentioned. That is, scanning is started by measurement light by linear irradiation (step S51). Thereafter, the light source device 18 starts scanning in either the X-axis direction or the Y-axis direction while adjusting the scanning direction by the irradiation direction adjusting unit 19 (step S52), and the leakage determining unit 106 performs gas leakage. Is detected (step S53), an alarm is transmitted from the alarm device 80 (step S57).

  On the other hand, if the leakage determination unit 106 does not detect gas leakage in step S53, scanning in either the X-axis direction or the Y-axis direction is terminated (step S54), and whether or not scanning in the detection necessary area C10 is completed. Is confirmed (step S55), and when the scanning is completed, the process proceeds to the leakage region specifying step. On the other hand, if the scanning of the detection necessary area C10 has not been completed, scanning of the scanning point in either the X axis direction or the Y axis direction is started, and the process returns to step S52 to scan within the detection necessary area C10. I do.

  In this way, in the present embodiment, the leakage determination unit 106 adjusts the irradiation direction of the light source device 18 so as to be in any direction within the inspection target region C10 after detecting the leakage of the gas. Can be narrowed down when scanning.

(Seventh embodiment)
Next, an operation of gas leak detection by the gas leak detection system according to the seventh embodiment of the present invention will be described with reference to the drawings. FIG. 18 is a flowchart of an operation of gas leak detection by the gas leak detection system according to the present embodiment, and FIG. 19 is an operation explanatory diagram of a gas leak region specifying step by the gas leak detection system according to the present embodiment.

  In the present embodiment, as shown in FIG. 19, the laser light emitted from the light source device 18 is not diffused laser light but collimated laser light, and the optical path of the laser light oscillated from the light source device 19 is changed. A reflection optical system 36 is provided. That is, in the present embodiment, in order to be able to detect a gas leak occurring at a site between the obstacles 34 and 35 and behind such that the laser beam irradiated from the light source device 18 does not reach, the laser beam is detected. A reflection optical system 36 for changing the optical path is provided.

  In the present embodiment, scanning is started by measurement light by linear irradiation (step S61). Thereafter, the leakage determination unit 106 determines whether or not there is a gas leakage (step S62). If it is detected that there is a gas leakage, the process proceeds to the leakage region specifying step shown in each of the above embodiments.

  On the other hand, if the leakage determination unit 106 does not detect gas leakage in step S62, it is determined that there is no gas leakage in the optical path of the laser light of the light source device 19, and then the reflection optical system 36 is inserted into the measurement optical path ( Step S63). Thereafter, the leakage determination unit 106 determines whether or not there is a gas leakage (step S64). In this way, in the present embodiment, the optical path of the laser light from the light source device 19 can be changed by the reflection optical system 36, so that the laser light from the light source device 19 such as behind the obstacle 34 does not reach directly. However, the laser beam can be scanned.

  Although each embodiment of the present invention has been described in detail as described above, it is easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. It will be possible. Therefore, all such modifications are included in the scope of the present invention.

  For example, a term described with a different term having a broader meaning or the same meaning at least once in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. In each of the above embodiments, the case of combustible gas has been described as a gas leakage detection target. However, the present invention is a detection method using infrared absorption of gas, and absorbs infrared light at a specific wavelength. Any gas having a spectrum is applicable even if it is not a combustible gas. Further, the configuration and operation of the gas leakage detection system are not limited to those described in the embodiments of the present invention, and various modifications can be made.

DESCRIPTION OF SYMBOLS 10 Light source device 11 Light source 20 Light receiving sensor 30 Obstacle 40 Measurement unit 50 AD converter 60 Display unit 70 Storage unit 80 Alarm device 100 Gas leak detection system 102 Central controller 106 Leak determination unit 108 Leak area specification unit 110 Laser light switching unit 112 Detection range changing unit 114 Diffusion angle adjusting unit P10, P30 (Gas) leakage point

Claims (4)

A gas leak detection system for detecting a gas leak in an inspection target area having an obstacle that reflects laser light,
A light source device for irradiating a diffused laser beam obtained by diffusing a laser beam having an absorption wavelength specific to the gas oscillated from a light source;
A light receiving sensor provided at a position where a length of an optical path to the light source device is a specified value, and receiving reflected light of the diffused laser light reflected by the obstacle;
After irradiating the diffused laser light, a leakage determination unit for determining the presence or absence of leakage of the gas from the absorption wavelength of reflected light received by the light receiving sensor;
By adjusting at least one of the diffusion laser light emitted from the light source device, the detection direction of the light receiving sensor, and the detection range of the light receiving sensor after detecting the leakage of the gas by the leakage determination unit, A leakage area specifying part for specifying a gas leakage area ;
A detection range changing unit for changing a range of detecting the reflected light of the light receiving sensor,
The leak region specifying unit specifies the gas leak region by controlling the detection range changing unit to change the detection range of the light receiving sensor after the leak determination unit detects the gas leak. gas leak detection system according to claim to Rukoto. A plurality of the light receiving sensors are provided in parallel, and each light receiving sensor has a different detection range,
The leak region specifying unit specifies the gas leak region based on an inspection result of whether any of the light receiving sensors detects gas leak after the leak determination unit detects the gas leak. The gas leakage detection system according to claim 1. A diffusion angle adjustment unit that adjusts the irradiation angle of the diffusion laser light of the light source device stepwise;
The leakage region specifying unit controls the diffusion angle adjustment unit to adjust the irradiation angle of the diffusion laser light stepwise after the leakage determination unit detects the leakage of the gas, thereby leaking the gas. The gas leak detection system according to claim 1 or 2 , wherein an area is specified. After irradiating the diffused laser beam, when the leakage determination unit determines that leakage of the gas is present, according to any one of claims 1 to 3, characterized in that the alarm device unit is further provided to the alert Gas leak detection system.

Images