JP4823020B2 - Gas concentration monitoring system, fixed station and mobile station, and gas concentration measuring method - Google Patents

Description

  The present invention is a natural gas plant, a natural gas pipeline, a chemical plant, and other facilities that may generate or emit gas, and the vicinity thereof, an underground parking lot, a tunnel, a congested road, a highway toll gate, or a greenhouse gas. Concentration monitoring system that analyzes and monitors the gas concentration of abnormal gas in the atmosphere in a wide field of abnormal gas monitoring areas affected by the weather, such as areas subject to underground disposal, fixed and mobile stations for receiving laser light And a gas concentration measurement method.

  In addition, abnormal gases in the atmosphere (air) include not only greenhouse gases (GHG) such as carbon dioxide, methane, halocarbons, ground ozone, and carbon monoxide, but also nitrogen monoxide, nitrogen dioxide, sulfur dioxide, and ammonia. , Other combustible gases, nitrous oxide, hydrofluorocarbon (HFC), perfluorocarbon (PFC), sulfur hexafluoride (SF6), exhaust gas discharged from vehicles or various plants, etc. Gas that has a higher proportion than normal atmospheric components.

The applicant of the present application uses the Tunable Diode Laser Absorption Spectroscopy (hereinafter referred to as the near infrared wavelength TDLAS method) method using the near infrared wavelength shown in FIGS. A measuring device was proposed. (For example, Patent Document 1)
The gas concentration measuring device is described in Mitsubishi Heavy Industries Technical Report Vol. 41 no. 4 (2004-7), pages 208-211. (For example, Non-Patent Document 1)

In this conventional gas concentration measuring apparatus, a laser oscillator is provided in the light source unit 20 as shown in FIGS.
The laser oscillator includes an LD module 21, a mirror 22 a that reflects the laser light oscillated from the LD module 21, a part of the laser light reflected by the mirror 22 a toward the optical window 25 and a part of the laser light. A half mirror 22b that transmits light and a mirror 22c that reflects the laser light transmitted through the half mirror 22b toward the reference cell 23 are provided.

Further, a measurement photodiode 45 and a background light photodiode 46 are provided in the vicinity of the optical window of the light receiving unit.
The measurement photodiode 45 is arranged on the laser optical axis and receives the laser light that has passed above the measurement area.
The background light photodiode 46 is disposed away from the laser optical axis and receives background light (background) in the measurement area.
The measurement photodiode 45 and the background light photodiode 46 are connected so as to send a light reception signal to the AD converter AD via the measurement unit 27.
The AD converter AD is connected to the central control monitoring device 10, and the central control monitoring device 10 is further connected to a display device having a display.

The conventional gas concentration measuring apparatus is configured as described above, and the laser light oscillated from the LD module 21 is divided into two by the half mirror 22b.
Of these, the transmitted light passes through the reference cell 23 and is received by the reference photodiode 24, and is used for gas concentration verification and wavelength stabilization.
On the other hand, the reflected light is introduced into the measurement area via the optical window 25 and is received by the measurement photodiode 45 after passing through the measurement area.

Further, the background light emitted from the measurement region is received by the background light photodiode 46 disposed at a position off the optical axis of the measurement laser light.
The measurement unit 27 processes electrical signals from the reference photodiode 24, the measurement photodiode 45, and the background light photodiode 46.
The measurement unit 27 sends the processed analog data to the AD converter AD, which converts the analog data into digital data, which is sent to the central control and monitoring device 10.
The central control and monitoring device 10 stores the sent data in a memory, and digitizes or graphs this data and displays it on the screen of a display device (not shown).
Further, the central control monitoring device 10 calculates the difference between the intensity of the light received by the measurement photodiode 45 (laser light + background light) and the intensity of the light received by the background light photodiode 46 (background light). This is also displayed on the screen of the display device.

  In FIG. 16, 80 is a ramp wave generator, 81 and 82 are sine wave generators, 83 is an adder, 84 is an amplifier, 85, 86 and 88 are phase sensitive detectors, 87 is a low-pass filter, and 89 is It is an amplifier / low-pass filter.

  However, Patent Document 1 or Non-Patent Document 1 does not disclose how to analyze and monitor the gas concentration of abnormal gas in the atmosphere in a wide outdoor field affected by the weather.

The applicant of the present application has proposed the gas concentration monitoring system shown in FIGS. (For example, Patent Document 2)
In Patent Document 2 shown in FIG. 17, the concentration of the greenhouse gas is detected on the surface side of the storage target area of the greenhouse gas underground disposal site, and leaks from the greenhouse gas underground disposal site storage target area 103 to the ground surface. A gas concentration monitoring system for monitoring incoming greenhouse gases, which is provided on a pole set up in the greenhouse gas underground disposal site storage target area 103 and has an absorption wavelength specific to the greenhouse gas species to be measured. At least one light source unit 100 that oscillates laser light toward the atmosphere existing in the vicinity of the ground surface of the greenhouse gas underground disposal site storage target area 103 and the movable body 102 are provided so as to be movable, and the greenhouse effect is provided. At least one light receiving unit 101 that receives the laser light oscillated from the light source unit that has passed through the atmosphere existing near the ground surface of the gas underground disposal site storage target area 103; Modulating the oscillation wavelength of the laser light oscillated from the light source unit 100, demodulating the modulated signal from the signals received by the light receiving unit 101, and the concentration of the greenhouse gas species to be measured based on the demodulated signal And a wavelength tunable semiconductor laser absorption spectroscopic means for obtaining the above.
Further, Patent Document 2 also describes a configuration in which the reflecting portion 104 is fixedly arranged in the storage target area 103 as illustrated in FIG.

  However, in the case shown in FIGS. 17 and 18, since the greenhouse gas leaked to the ground surface is moved by the wind or the like in the field affected by the weather, in order to specify the emission position of the greenhouse gas. Further improvements are needed.

In the case shown in FIG. 17, it is necessary to always move the moving body 102 in order to constantly monitor in a wide outdoor field, and the measurement work becomes complicated.
Further, in the case shown in FIG. 18, for example, when the gas concentration is monitored in a wide storage target area 103 having a radius of 2 km, in order to specify the position of the leaking greenhouse gas, for example, at a pitch of 100 m In the case of disposing the reflection portion 104, a total of several hundred reflection portions 104 are necessary.

On the other hand, as shown in FIG. 19, in an area equipped with a combustible gas storage facility or the like, a detection unit 111 is arranged at the center of a plurality of tanks 110 and a reflecting mirror 112 is provided around the area, so It has been proposed to detect the gas leakage by setting the measurement optical path 113 and sequentially switching the projection direction of the infrared laser with one set of units. (For example, Patent Document 3)
However, since the combustible gas leaked by wind or the like moves also in the one shown in FIG. 19, it is difficult to accurately specify the position where the combustible gas leaks depending on the weather (especially wind).

JP 2001-74653 A JP 2004-219379 A Japanese Patent Laid-Open No. 56-147034 Mitsubishi Heavy Industries Technical Report Vol. 41 no. 4 (2004-7), pp. 208-211

  The present invention has been proposed to solve such problems, and gas concentration monitoring that can analyze and monitor the concentration of abnormal gas in the atmosphere (air) in consideration of the influence of the weather. It is an object to provide a system, a fixed station and a mobile station for receiving laser light, and a gas concentration measurement method.

  The present invention has been made to solve the above-described conventional problems, and each of the inventions described in the claims includes a gas concentration monitoring system, a fixed station and a mobile station for receiving a laser beam used in the system, As the gas concentration measuring method, each means described below is adopted.

(1) The gas concentration monitoring system according to the first means is:
At least one light source unit having an LD module which is arranged in the gas abnormality monitoring area and emits laser light having an absorption wavelength specific to the gas to be measured toward the gas abnormality monitoring area;
A turning and tilting mechanism for controlling a light projection direction and an elevation angle of the laser light emitted from the light source unit;
It has a measurement photodiode that is arranged around the light source unit in the gas abnormality monitoring area and receives the laser light emitted from the light source unit , and the illuminance measured by the illuminance meter and the illuminance meter is a predetermined value. A plurality of fixed stations having shutters that close when exceeding
An anemometer installed in the fixed station;
A gas concentration calculator for calculating a gas concentration in the atmosphere between the light source unit and the fixed station based on a laser beam measurement value measured by the measurement photodiode of the fixed station, and an anemometer A central control monitoring device having a superimposed display creation device for calculating a gas ejection assumed range of the gas concentration calculated based on the measured wind direction value and the measured wind velocity value;
A storage device for storing the measurement value and the calculation result;
And a display for displaying the calculation result.

(2) The gas concentration monitoring system according to the second means is the first means,
The light source unit is
The LD module;
A reference cell that encloses a gas to be measured at a predetermined gas concentration and transmits a part of light emission from the LD module;
A reference photodiode that receives the transmitted light transmitted through the reference cell;
The fixed station is
A background light photodiode is provided at a position away from the measurement photodiode.

(3) The gas concentration monitoring system according to the third means is the second means,
The fixed station is
A control monitoring device that collects each measurement value measured by the measurement photodiode, the background light photodiode, and the anemometer, and generates and transmits a measurement value transmission signal;
An operation panel with indicator that can adjust each device and display the cause of failure,
It is characterized by having.

(4) The gas concentration monitoring system according to the fourth means is the second or third means,
The gas concentration calculator of the central control and monitoring device is to obtain the gas concentration C in the atmosphere by the following equation:
Atmospheric gas concentration C = {(laser light measurement value DX−background light measurement value DN) / reference gas concentration measurement value Do} × (reference cell length Lo / measurement section distance L) × reference cell gas concentration Co,
However,
Laser beam measurement value DX: Measurement value by measurement photodiode,
Background light measurement value DN: Measurement value by a background light photodiode,
Reference gas concentration measurement value Do: measurement value by reference photodiode,
Reference cell length Lo: length of reference cell,
Measurement section distance L: distance from the light source unit to the measurement photodiode,
Reference cell gas concentration Co: concentration of gas sealed in the reference cell.

(5) The gas concentration monitoring system according to the fifth means is any one of the first to fourth means,
The central control and monitoring device calculates the direction and elevation angle of the light source unit from the installation position of the fixed station and the installation position of the light source unit, and directs the light source unit toward the fixed station, and then the orientation and elevation angle of the light source unit. And a specified position calculator for specifying a position where the measured value of the laser beam from the measurement photodiode of the fixed station is maximized, within a predetermined scanning width and scanning height range. It is characterized by that.

(6) The gas concentration monitoring system according to the sixth means is the fifth means,
The central control monitoring device performs position specification by the specific position calculator at least twice in the predetermined scanning width and scanning height range and in a predetermined scanning width and scanning height range smaller than the predetermined scanning width and scanning height. It is characterized by being.

(7) The gas concentration monitoring system according to the seventh means is any one of the first to sixth means,
The superimposed display creation device of the central control monitoring device selects the gas concentration at the fixed station on the windward side when there are a plurality of the gas concentrations calculated at an arbitrary measurement point. And

(8) The gas concentration monitoring system according to the eighth means is any one of the first to seventh means,
The fixed station is
It has a solar cell for generating electric power, a secondary battery for storing electric power, and a charge / discharge board for charging the secondary battery with electric power generated by the solar cell and supplying electric power to various devices in the fixed station It is characterized by that.

(9) The gas concentration monitoring system according to the ninth means is any one of the first to eighth means,
The fixed station is
It has a concave mirror which condenses the laser beam from the said light source unit, and a reflective mirror smaller than the said concave mirror.

(10) The gas concentration monitoring system according to the tenth means is any one of the second to ninth means,
Further, a measurement photodiode that is movably disposed in the gas abnormality monitoring area and receives the laser beam emitted from the light source unit, a background light photodiode installed at a position away from the measurement photodiode, and A mobile station for receiving laser light having an anemometer is provided.

( 11 ) The gas concentration monitoring system according to the eleventh means comprises the tenth means,
The mobile station
A concave mirror for condensing the laser light from the light source unit and a reflective mirror smaller than the concave mirror;
An anemometer,
A parabolic antenna for detecting a direction of the light source unit and a wireless direction detector;
It is characterized by having.

( 12 ) The gas concentration monitoring system according to the twelfth means is the tenth or eleventh means,
The mobile station
It has a GPS antenna and a GPS receiver for measuring the installation position of the mobile station.

( 13 ) The gas concentration monitoring system according to the thirteenth means is the twelfth means,
The mobile station
A control monitoring device that collects each measurement value measured by the measurement photodiode, the background light photodiode, the anemometer and the GPS receiver, and creates and transmits a measurement value transmission signal;
An operation panel with indicator that can adjust each device and display the cause of failure,
It is characterized by having.

(14) In the gas concentration monitoring system according to the fourteenth means, in any one of the tenth to thirteenth means,
The gas concentration calculator of the central control and monitoring device obtains the gas concentration in the atmosphere from the following equation for the mobile station.
Atmospheric gas concentration C = {(laser light measurement value DX−background light measurement value DN) / reference gas concentration measurement value Do} × (reference cell length Lo / measurement section distance L) × reference cell gas concentration Co,
However,
Laser beam measurement value DX: Measurement value by measurement photodiode,
Background light measurement value DN: Measurement value by a background light photodiode,
Reference gas concentration measurement value Do: measurement value by reference photodiode,
Reference cell length Lo: length of reference cell,
Measurement section distance L: distance from the light source unit to the measurement photodiode,
Reference cell gas concentration Co: concentration of gas sealed in the reference cell.

( 15 ) The gas concentration monitoring system according to the fifteenth means is any one of the tenth to fourteenth means,
The specific position calculator of the central control monitoring device calculates the direction and elevation angle of the light source unit from the installation position of the mobile station and the installation position of the light source unit, and directs the light source unit to the mobile station, and then The position at which the laser beam measurement value from the measurement photodiode of the mobile station for receiving the laser beam is maximized by scanning within the range of the predetermined scanning width and scanning height in which the direction and elevation angle of the light source unit are set It is characterized by specifying.

( 16 ) The fixed station for receiving laser light according to the sixteenth means is
A measurement photodiode that receives the laser light emitted by the light source unit;
A concave mirror for condensing the laser light from the light source unit and a reflective mirror smaller than the concave mirror;
A background light photodiode installed at a position away from the measurement photodiode;
An anemometer that measures the wind speed of the surrounding wind direction,
A luminometer,
A shutter that closes when the illuminance measured by the illuminometer exceeds a predetermined value;
A control monitoring device that collects each measurement value measured by the measurement photodiode, the background light photodiode, and the anemometer, and generates and transmits a measurement value transmission signal;
A solar cell that generates electric power;
A secondary battery for storing electric power;
A charging / discharging panel for charging the power generated by the solar cell to the secondary battery and supplying power to various devices in the fixed station;
An operation panel with indicator that can adjust each device and display the cause of failure,
It is provided with.

( 17 ) The laser beam receiving mobile station according to the seventeenth means is
A measurement photodiode that receives the laser light emitted by the light source unit;
A concave mirror for condensing the laser light from the light source unit and a reflective mirror smaller than the concave mirror;
A background light photodiode installed at a position away from the measurement photodiode;
An anemometer that measures the wind speed of the surrounding wind direction,
A luminometer,
A shutter that closes when the illuminance measured by the illuminometer exceeds a predetermined value;
A GPS antenna and GPS receiver for measuring the installation position;
A tilt-slewing drive device for controlling the direction and elevation angle of the measurement photodiode;
A control monitoring device that collects each measurement value measured by the measurement photodiode, the background light photodiode, the anemometer, and a GPS receiver, and creates and transmits a measurement value transmission signal;
An operation panel with indicator that can adjust each device and display the cause of failure,
It is provided with.

( 18 ) The gas concentration measuring method according to the eighteenth means is
At least one light source unit having an LD module which is arranged in the gas abnormality monitoring area and emits laser light having an absorption wavelength specific to the gas to be measured toward the gas abnormality monitoring area;
A turning and tilting mechanism for controlling a light projection direction and an elevation angle of the laser light emitted from the light source unit;
It has a measurement photodiode and an anemometer that are arranged around the light source unit in the gas abnormality monitoring area and receives the laser light emitted from the light source unit, and is measured by an illuminometer and the illuminometer. A plurality of fixed stations for receiving laser light having a shutter that closes when the illuminance exceeds a predetermined value ;
A mobile station for receiving laser light, which is movably disposed in the gas abnormality monitoring area and has a measurement photodiode for receiving the laser light emitted by the light source unit and an anemometer, and
Always measure the gas abnormality by the fixed station,
When a gas abnormality is detected, the abnormality of the gas is measured by the mobile station on the windward side of the fixed station where the gas abnormality is detected.

  Since the invention according to each claim described in the claims employs each of the above means, the gas concentration of the abnormal gas in the atmosphere (air) is considered in consideration of the influence of the weather, particularly the wind direction and wind speed. Can be analyzed and monitored.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is an overall layout diagram of a gas concentration monitoring system according to a first embodiment of the present invention.
FIG. 2 is a schematic diagram of the gas input / monitoring center 6 including the light source unit 20 shown in FIG.
FIG. 3 is a schematic diagram of the fixed station 8 for receiving laser light shown in FIG.
FIG. 4 is a schematic diagram of the mobile station 9 for receiving laser light shown in FIG.
FIG. 5 is a control block diagram in the case of measurement by the fixed station 8 in the central control monitoring apparatus 10 shown in FIG.
FIG. 6 is a specific detailed control block diagram of the specific position shown in FIG.
FIG. 7 is a detailed control block diagram of the gas concentration detection / calculation shown in FIG.
FIG. 8 is a control block diagram in the case of measurement by the mobile station 9 in the central control monitoring apparatus 10 shown in FIG.
FIG. 9 is a diagram illustrating a method for specifying the specific position illustrated in FIG. 6.
FIG. 10 is a diagram showing a display example of the display 12 shown in FIG.
FIG. 11 is a schematic diagram showing a method for specifying the position of the leaked gas according to the first embodiment of the present invention.

[Overall Configuration in the First Embodiment]
First, the overall configuration of the gas concentration monitoring system according to the first embodiment of the present invention will be described with reference to FIG.
The example shown in FIG. 1 is an example of a CO ₂ gas underground disposal plant that stores CO ₂ gas, which is one of the abnormal gases in the atmosphere (air), in the ground.
As shown in FIG. 1, there are a plurality of steel pipe piles or the like at appropriate places in the gas abnormality monitoring area 4 which is a storage target area of a CO ₂ gas underground disposal plant having a radius of 2 km, for example, which is wide in the field affected by the weather. The storage input port 5 is driven deep into the ground.

The lower end of the storage input port 5 reaches the closed aquifer 1 or the quasi-fossil salt water layer 2 existing several hundred meters to several kilometers underground.
An unillustrated CO ₂ separation and recovery device (not shown) and a gas press-fitting machine communicate with the storage input port 5, and the CO ₂ gas passes through the storage input port 5 through the closed aquifer 1 or the quasi-fossil salt water layer 2. Is press-fitted with a predetermined pressure.
The CO ₂ gas injected into the closed aquifer 1 is stored in the form of a CO ₂ supercritical fluid.
In addition, the CO ₂ gas injected into the semifossil salt water layer 2 flows into the sea 3 beyond the salt boundary and is immobilized by reacting with seawater components.

A gas input / monitoring center 6 is installed at the center of the gas abnormality monitoring area 4 or at an appropriate place.
A pole or a steel tower is installed on the gas input / monitoring center 6, and a light source unit 20 of the laser light transmitting station 7 is installed on the top of the steel tower.
Further, in the gas input / monitoring center 6, a central control monitoring device 10, a storage device 11, a display device 12 (see FIG. 2), a CO ₂ separation and recovery device, a gas press-in machine, and a gas press-in machine control panel described later Etc. are also installed.
The pole or steel tower and the light source unit 20 may be installed in a place where the entire range of the gas abnormality monitoring area 4 can be seen, and the gas input / monitoring center 6 may be installed separately in a convenient place for traffic. good.

A fixed station 8 for receiving a laser beam is installed at an appropriate location on the periphery of the gas abnormality monitoring area 4.
Further, a fixed station 8 for receiving a laser beam is appropriately installed in a depressed portion or a low portion where CO ₂ tends to stay in the gas abnormality monitoring area 4 as necessary.
Furthermore, at least one mobile station 9 for receiving a laser beam mounted on a vehicle or the like is provided.

[Configuration of laser beam transmission station]
Next, the configuration of the laser beam transmitting station 7 constituted by the light source unit 20, the gas input / monitoring center 6 and the like will be described in detail with reference to FIG.
In FIG. 2, the same reference numerals as those in FIGS. 15 and 16 are the same members, and the near infrared wavelength TDLAS method described in Patent Document 1 (see FIGS. 15 and 16) previously proposed is used. A gas concentration measuring device is used.

As shown in FIG. 2, in the laser beam transmission station 7, the light source unit 20 is installed on the top of the pole 28 on the gas input / monitoring center 6 via a turning and tilting mechanism 30.
The turning drive mechanism 30 drives the direction of the light source unit 20 up, down, left, and right, and turns the turntable 34, the turning shaft 33, and the turntable 34 that are turnably provided on the top of the pole 28. Driving device 36 for turning such as a gear motor with a brake, vertical member 32 provided in the lower part of the light source unit 20, a horizontal shaft 31 connecting the vertical member 32 and the turntable 34, and the light source unit 20 are driven in an up-and-down direction (inclination). And a tilting drive unit 35 such as a gear motor with a brake to be driven.

(Light source unit)
15 and 16, in the light source unit 20, the LD module 21, the mirror 22a that reflects the laser light oscillated from the LD module 21, and the laser light reflected by the mirror 22a A half mirror 22b that partially reflects toward the optical window 25 and partially transmits, a mirror 22c that reflects laser light that has passed through the half mirror 22b toward the reference cell 23, and a laser that has passed through the reference cell 23 A reference photodiode 24 for receiving light is provided.
The reference cell 23 has a predetermined reference cell length Lo, and CO _{2 to} be measured is enclosed in the reference cell 23 at a predetermined gas concentration Co.
The reference gas concentration measurement value Do detected by the reference photodiode 24 is input to the measurement unit 27 and used for gas concentration verification and wavelength stabilization, as shown in FIG.

Note that the LD module 21 as a light source includes, for example, a semiconductor laser element, a Peltier element for adjusting the temperature of the semiconductor laser element, and the like.
This semiconductor laser device is not limited to this, and can be applied to all other laser oscillators that can perform wavelength modulation. Furthermore, in the case of light and electromagnetic waves other than lasers, wavelength modulation is also possible. All are applicable.
In addition, an illuminance meter 44p that measures the illuminance in the direction in which the light source unit 20 faces is provided on the front surface of the light source unit 20.

Furthermore, a radio direction detection radio wave transmitting antenna 38 that transmits a radio direction detection radio wave is provided above the light source unit 20 so that the mobile station 9 described later detects the direction of the light source unit 20.
Note that the radio direction detection radio wave transmission antenna 38 and the radio direction detection radio wave transmitter 39 described later are not necessarily required, and use radio waves transmitted from the data transmission / reception antenna 41p and the radio transceiver 42p described later. Thus, the mobile station 9 may detect the direction of the light source unit 20.

(Gas input / monitoring center)
In the gas input / monitoring center 6, the data measured by various measuring instruments and the central control monitoring device 10 for controlling the turning tilt mechanism 30 and the like, the data measured by various measuring instruments and the calculation are calculated. A storage device 11 for storing various data, a display device 12 and a keyboard 13 are provided.
In addition, the gas input / monitoring center 6 receives the data transmission / reception antenna 41p, the wireless transceiver 42p, and the wireless transceiver 42p that communicate with the laser light receiving fixed station 8 or the mobile station 9 shown in FIG. A DA converter DA is provided for converting the signal and transmitting data to the measurement unit 27 described later.

Further, the gas input / monitoring center 6 is also provided with an anemometer 40p, a thermometer 43p, and an AD converter AD that converts data to be transmitted to the central control monitoring device 10.
Then, the wind direction measurement value WDo, the wind speed measurement value WVo, and the temperature To in the vicinity of the light source unit 20 measured by the wind direction anemometer 40p and the thermometer 43p are transmitted to the central control monitoring device 10 via the AD converter AD.
The central control and monitoring device 10 stores these data in a predetermined memory area of the storage device 11 together with the data number j and the measurement date / time TMj.

In the gas input / monitoring center 6, a radio azimuth detecting radio wave transmitter 39 that transmits radio azimuth detecting radio waves to the radio azimuth detecting radio wave transmitting antenna 38 based on a transmission start signal from the central control monitoring device 10 is also provided. It has been.
In the gas input / monitoring center 6, there is also provided a turning inclination control device 37 for controlling the inclination driving machine 35 and the turning driving machine 36.
Further, an AD converter AD for converting an illuminance signal measured by the illuminance meter 44 p in the light source unit 20 is also provided in the gas input / monitoring center 6.

In the gas input / monitoring center 6, an LD driver unit 26, a measuring unit 27, and an AD converter AD are also provided in the same manner as shown in FIGS. 15 and 16.
The LD driver unit 26 is connected to the LD module 21 in the light source unit 20, and sets the temperature and current of the LD module 21 and sets the transmission wavelength of the laser light.

(Measurement unit)
A reference gas concentration measurement value Do measured by the reference photodiode 24 in the light source unit 20 is input to the measurement unit 27.
Further, the measurement unit 27 includes a measurement photodiode 45f and a background light photodiode in a fixed station 8 for receiving laser light, which will be described later, via a data transmission / reception antenna 41p, a wireless transceiver 42p, and a DA converter DA. The laser light measurement value DXj and the background light measurement value DNj measured at 46f, or the laser light measurement value DXj measured by the measurement photodiode 45m and the background light photodiode 46m in the mobile station 9 described later, and The background light measurement value DNj is input.

The input reference gas concentration measurement value Do, laser light measurement value DXj, and background light measurement value DNj are digitally output by the AD converter AD after the high-frequency component is removed by the low-pass filter 87 in the measurement unit 27. It is converted into a signal and transmitted to the central control and monitoring device 10.
The central control and monitoring device 10 stores these data in a predetermined memory area of the storage device 11 together with the data number j and the measurement date / time TMj.

(Memory)
The storage device 11 has a memory area in which the following data is stored.
a) Common data (can be modified with keyboard 13)
The topographic map of the gas abnormality monitoring area 4, the reference cell length Lo, the position Po of the light source unit 20 (latitude xo, longitude yo, altitude Ho), the number i of the fixed station 8 for receiving laser light and the position information Pi (number i) , Latitude xi, longitude yi, altitude Hi, distance Li to the fixed station 8), where i = 1 to n.

b) Data / data number j for fixed station 8 or mobile station 9 for laser beam reception, measurement date / time TMj, reference gas concentration measurement value Doj
-Position information Pj of the measured fixed station 8 or mobile station 9 (number i of the measured fixed station 8 or latitude xj, longitude yj, altitude Hj of the measured position, measurement section distance to the fixed station 8 or mobile station 9 Lj)
Wind direction measurement value WDj, wind speed measurement value WVj, temperature Tj at fixed station 8 or mobile station 9
・ Wind direction measurement value WDoj, wind speed measurement value WVoj, temperature Toj at the gas input / monitoring center 6
Laser light measurement value DXj, background light measurement value DNj, calculated atmospheric gas concentration Cj

The data number i for the fixed station 8 and the data number j for the mobile station 9 are consistent numbers that do not overlap.
In the present specification and drawings, i in the code is a serial number of the fixed station 8, and j in the code is a consistent number of the measurement data group measured by the fixed station 8 or the mobile station 9. And may be omitted in the specification and drawings.
In this specification, the various measured values and the sign of the calculated value are those after high frequency components are removed, those before the AD converter (analog signal), those after the AD conversion (digital signal), etc. The same reference numerals are used.

The data stored in the storage device 11 is not only the display of the latest measurement value based on the command input from the keyboard 13, but also the transition of the gas concentration Cj in the atmosphere from the past to the present at a specific position. It can be displayed on the display 12 via the central control monitoring device 10.
When the fixed station 8 is added or abolished, the above-mentioned data of the added fixed station 8 can be added and the data of the abandoned fixed station 8 can be deleted by the keyboard 13.

(Central control monitoring device)
The central control and monitoring apparatus 10 includes calculation sub-blocks such as a topographic map collator 14, a gas concentration calculator 15, a specific position scanner 16, and a superimposed display creator 17.
The central control and monitoring device 10 manages various measured data, writes the data to the storage device 11, reads it out, displays it on the display device 12, etc., details of which will be described later.
The central control and monitoring device 10 is in the form of a large computer, and the central control and monitoring device 10 also incorporates a function as a gas press-fitting machine control panel as a calculation program.
However, the central control monitoring device 10 may be a computer dedicated to the gas concentration monitoring system.

[Configuration of fixed station for laser beam reception]
Next, the configuration of the fixed station 8 for receiving laser light will be described in detail with reference to FIG.
3 includes a light receiving unit in a gas concentration measuring apparatus using the near infrared wavelength TDLAS method described in Patent Document 1 (see FIGS. 15 and 16) previously proposed.

As shown in FIG. 1, the fixed station 8 for receiving laser light has its front face directed to the light source unit 20 at the periphery of the gas abnormality monitoring area 4, or at a depressed place or a low place where CO ₂ tends to stay. It is installed as appropriate.
As shown in FIG. 3, the fixed station 8 includes a collection of each measurement value from various measuring instruments in the fixed station 8, control of each device, creation of a measurement value transmission signal, and a laser beam transmission station 7. A control monitoring device 47f for controlling the communication is provided.

The fixed station 8 is provided with a data transmission / reception antenna 41f and a radio transceiver 42f that communicate with the gas input / monitoring center 6 shown in FIGS.
Further, the fixed station 8 is provided with an AD converter AD that converts data to be transmitted to the anemometer 40f, the thermometer 43f, the illuminometer 44f, and the control monitoring device 47f.
The wind direction measurement value WDj, wind speed measurement value WVj, temperature Tj, or illuminance in the vicinity of the fixed station 8 measured by the wind direction anemometer 40f, the thermometer 43f, or the illuminance meter 44f is controlled and monitored via the AD converter AD. It is transmitted to the device 47f.

In the fixed station 8, a measurement photodiode 45f and a background light photodiode 46f similar to those shown in FIG. 15 or FIG. 16 are also provided.
The background light photodiode 46f is disposed as far as possible from the optical axis of the measurement laser light R (or the measurement photodiode 45) so as to face the same direction as the measurement photodiode 45f. .
Further, in front of the measurement photodiode 45f, a large concave mirror 51 having a hole for passing laser light at the center and a front side of the concave mirror 51 in order to collect the laser light R emitted from the light source unit 20. And a small reflecting mirror 52 (convex mirror or flat mirror).
The laser light measurement value DXj and the background light measurement value DNj measured by the measurement photodiode 45f and the background light photodiode 46f are transmitted to the control monitoring device 47f via the AD converter AD.

Further, among the fixed stations 8 that are not facing north, the sun light that may be collected from the concave mirror 51 and the concave mirror 51 and hit the measurement photodiode 45f may be placed on the front surface of the fixed station 8 as necessary. A shutter 48 and a shutter driving device 49 are provided.
In addition, a fence 70 is provided in front of the fixed station 8 to prevent sun and rain.
When the illuminance measured by the illuminance meter 44f exceeds a predetermined value, the shutter 48 is automatically closed by the shutter driving device 49 based on a command from the control monitoring device 47f.

Further, the fixed station 8 includes a solar battery 53 that generates power, a secondary battery 55 that stores power, and power generated by the solar battery 53 as a power source for driving various devices in the fixed station 8. And a charge / discharge board 54 for charging the various devices in the fixed station 8 and supplying power to the various devices in the fixed station 8.
The driving power source may be supplied from the gas input / monitoring center 6 or the like by a power supply wire.

The control / monitoring device 47f also includes a failure diagnosis function for various devices in the fixed station 8, a function for determining a decrease in voltage abnormality of the secondary battery 55, and the like. The fixed station is determined to be abnormal.
Then, in response to a data transmission request from the laser beam transmission station 7, the control monitoring device 47f, the laser beam measurement value DXj, the background light measurement value DNj, the wind direction measurement value WDj, the wind speed measurement value WVj, the temperature Tj, and the fixed The station abnormality data is transmitted to the laser light transmitting station 7 through the wireless transceiver 42f and the data transmitting / receiving antenna 41f.

An operation panel 66f with a display is provided on the side wall of the fixed station 8.
The operation panel 66f with a display unit allows adjustment of each device in the fixed station 8, analysis of the cause of failure, display, and the like on the machine side.

[Configuration of mobile station for laser light reception]
Next, the configuration of the mobile station 9 for receiving laser light will be described in detail with reference to FIG.
The mobile station 9 for receiving laser light is basically provided with the same device as that of the fixed station 8 for receiving laser light.
The difference from the fixed station 8 is that a GPS antenna 56, a GPS receiver 57, a radio direction detector parabolic antenna 58, a radio direction detector 59, an inclination axis 60, an inclination axis drive 61, a turning axis 62, and a turning drive machine. 63, and the inclination turning drive device 64 is provided.
The mobile station 9 is mounted on a moving body 69 (vehicle or the like) at an arbitrary location in the gas abnormality monitoring area 4 and can be moved or carried by a person.

As for the power source, unlike the fixed station 8 (see FIG. 3), it is not always necessary to provide the solar cell 53, the charge / discharge panel 54, and the secondary battery 55. Although electric power may be supplied, a solar battery 53, a charge / discharge board 54 and a secondary battery 55, or a separate battery may be provided in the same manner as the fixed station 8.
Further, since the mobile station 9 is operated by an operator, it is not always necessary to provide the shutter driving device 49 and the laser light transmitting plate 50 shown in FIG. 3, but sunlight is not collected during an erroneous operation or during movement. As described above, the shutter driving device 49 and the laser light transmitting plate 50 may be provided.

As shown in FIG. 4, the mobile station 9 includes a collection of each measurement value from various measuring instruments in the mobile station 9, control of each device, creation of a measurement value transmission signal, and a laser beam transmission station 7. A control monitoring device 47f for controlling the communication is provided.
The mobile station 9 is connected to an operation panel 66m with a display via a cabtyre cable and a signal line connector.
The operation panel 66m with a display can adjust and operate each device in the mobile station 9 on the machine side.
In addition, a fence 70 is provided in front of the mobile station 9 to prevent sun and rain.

As shown in FIG. 4, the mobile station 9 is provided with a data transmission / reception antenna 41m and a radio transceiver 42m that communicate with the gas injection / monitoring center 6 shown in FIGS.
Further, the mobile station 9 is provided with an AD converter AD that converts data to be transmitted to the anemometer 40m, the thermometer 43m, the illuminance meter 44m, and the control monitoring device 47m.
Then, the wind direction measurement value WD, the wind speed measurement value WV, the temperature T, or the illuminance in the vicinity of the mobile station 9 measured by the wind direction anemometer 40m, the thermometer 43m, or the illuminance meter 44m is controlled and monitored via the AD converter AD. It is transmitted to the device 47m.

In the mobile station 9, a measurement photodiode 45m and a background light photodiode 46m similar to those shown in FIGS. 15 and 16 are provided.
In addition, a large concave mirror 51 having a hole for passing a laser beam in the center and a front part of the concave mirror 51 are disposed in front of the measurement photodiode 45m in order to collect the laser light emitted from the light source unit 20. A small reflecting mirror 52 (a convex mirror or a plane mirror) is provided.
The laser beam measurement value DXj or the background light measurement value DNj measured by the measurement photodiode 45m or the background light photodiode 46m is transmitted to the control monitoring device 47m via the AD converter AD.

Further, the mobile station 9 is provided with a GPS antenna 56 and a GPS receiver 57 so that the position (latitude x, longitude y) of the place where the mobile station 9 is installed can be measured.
The GPS antenna 56 and the GPS receiver 57 may be provided separately from the mobile station 9 and the measured position may be input from the operation panel 66m with a display.

The mobile station 9 is provided with a parabolic antenna 58 for a radio direction finder and a radio direction detector 59.
In addition, below the mobile station 9, an inclined shaft 60, an inclined shaft driving device 61, a turning shaft 62, a turning driving device 63, and an inclined turning drive device 64 are provided.

The mobile station 9 having the above-described configuration is moved and installed at a place where measurement is desired.
Then, the radio direction finding radio wave transmitted from the radio direction finding radio wave transmitting antenna 38 provided in the light source unit 20 is received by the radio direction finding parabolic antenna 58 and the wireless direction finding detector 59.
Next, the tilt axis driving device 61 and the swing driving device 63 are driven by the tilting and turning drive device 64, and the concave mirror 51, the reflecting mirror 52, and the reflecting mirror 52 and the reflecting mirror 52 Direct the measurement photodiode 45m.
When the installation of the mobile station 9 and the setting of the direction of the concave mirror 51, the reflecting mirror 52, and the measurement photodiode 45m are completed, measurement by the control monitoring device 47m is started.

  Then, the control monitoring device 47m detects the position (latitude xi, longitude yi) of the place where the mobile station 9 is installed, the laser light measurement value DXj and the background light measurement value DNj, the wind direction measurement value WDj, the wind speed measurement value WVj, and the temperature Tj. Is transmitted to the laser light transmitting station 7 through the wireless transceiver 42m and the data transmitting / receiving antenna 41m.

[Control in central control monitoring device]
Based on FIG. 5 to FIG. 7 and FIG. 9 to FIG. 11, the control when the central control monitoring device 10 performs measurement using the fixed station 8 will be described.

(Measurement by fixed station)
As shown in FIG. 5, measurement by the fixed station 8 is started periodically (or based on a command input from the keyboard 13), for example, once a day, for example (step S0).
At this time, the position Po (latitude xo, longitude yo, altitude Ho) of the light source unit 20 is read from the storage device 11.
First, the fixed station number i to be measured is set to 0 (zero) (step S1), and the fixed station number i is set to i = i + 1 (step S2).
Next, position information Pi (latitude xi, longitude yi, altitude Hi, measurement section distance Li) of the i-th fixed station 8 (hereinafter referred to as fixed station 8i) is read from the storage device 11 (step S3).

Note that the measurement section distance Li is not always necessary, and the position information Po (latitude xo, longitude yo, altitude Ho) of the light source unit 20 and the position information Pi (latitude xi, longitude yi, altitude Hi) of the fixed station 8i It may be calculated from
Further, when the measurement section distance L is calculated, the reference cell length Lo is several tens of centimeters, whereas the measurement section distance L is several hundred meters to several kilometers, and the measurement origin of the measurement section distance L (or will be described later). Even if Lm) is the exit of the LD module 21 or the exit of the optical window 25, the error due to this is 1% or less.

Next, a measurement start signal is transmitted to the fixed station 8i through the data transmission / reception antenna 41p and the wireless transceiver 42p (step S4).
Then, it waits for a preparation completion signal from the fixed station 8i for a predetermined time.
If there is no response from the fixed station 8i even after a predetermined time has elapsed, or if a fixed station abnormality signal is received from the fixed station 8i (step S5), it is determined that the fixed station 8i is abnormal. Measurement ends (step S16), and the process returns to step S2.
When the fixed station 8i is normal, the laser light measurement value DXj, the background light measurement value DNj, the wind direction measurement value WDj, the wind speed measurement value WVj, and the temperature Tj are transmitted from the fixed station 8i via the data transmission / reception antenna 41p and the wireless transceiver 42p. Is received (step S5).

From the position Po (latitude xo, longitude yo, altitude Ho) of the light source unit 20 and the position Pi (latitude xi, longitude yi, altitude Hi) of the fixed station 8i, the initial direction and elevation angle of the light source unit 20 are calculated (step) S6).
In this case, some of the light source unit 20 and the fixed station 8i are separated by about 2 km, and light is transmitted from the light source unit 20 only by controlling the direction and elevation angle of the light source unit 20 by the calculated direction and elevation angle. The measured measurement laser beam R is not necessarily received by the fixed station 8i.

  Therefore, the specific position scanner 16 (see FIG. 2) moves to the specific position where the laser beam measurement value DX measured by the measurement photodiode 45f is maximized with reference to the calculated initial direction and elevation angle. The tilting drive device 35 and the turning drive device 36 are connected via the turning inclination control device 37 so that the specific position is specified and the front surface of the light source unit 20 faces the fixed station 8i. Driven (first position scanning step S7a, second position scanning step S7b).

In the first position scanning step S7a, as shown in FIG. 6, first, a predetermined horizontal scanning width b, a height scanning width a, and a height direction centered on the initial orientation and elevation angle described above. A pitch ΔH is set (step S41).
Note that the horizontal scanning width b, the height scanning height a, and the height direction pitch ΔH may be set as constants in the program, stored in the storage device 11 and read out from the storage device 11. May be.
In the first position scanning step S7a, for example, the horizontal scanning width b = 10 m, the height scanning height a = 10 m, and the height direction pitch ΔH = 1 m are set.

Next, the height of the scanning start range is set to the maximum H + a (step S42).
Then, at this height H, the turning shaft 33 is driven (step S43), and the horizontal scanning in the range of the horizontal scanning width = ± b is performed (step S44), and the measurement photodiode 45f of the fixed station 8 is used. The measured laser beam measurement value DX is obtained (step S45).

Next, the horizontal axis 31 is driven to set the height H = H−the height direction pitch ΔH in the scanning start range (step S46).
Then, it is determined whether or not the height H <Ha of the scanning start range. If not, the process returns to step S43 to obtain the laser beam measurement value DX at the next height (steps S43 to S47). .

When it is determined that the height H <Ha of the scanning start range, the scanning is terminated, and a graph or data as shown in FIG. 9 is obtained.
Then, the lateral position (x, y) and the height H (that is, the direction and the elevation angle) of the specific position where the laser beam measurement value DX is maximized are calculated (step S48).
The horizontal shaft 31 and the turning shaft 33 are driven to this specific position (step S49), and the first position scanning (step S7a) is completed.

This first position scan has a pitch in the height direction ΔH = 1 m and a rough pitch.
Therefore, the range is narrowed down and the second scanning is performed as shown in FIG. 6 (second position scanning step S7b).
In the second position scanning step S7b, for example, the horizontal scanning width b = 1.5 m, the height scanning height a = 1.5 m, and the height direction pitch ΔH = 0.3 m are set.
Then, as shown in FIG. 6 again, the specific position is calculated in steps S41 to S49.
In this way, the front surface of the light source unit 20 is accurately directed to the fixed station 8i.

Next, as shown in FIG. 5, the measurement is started, and the laser beam measurement value DX, the background light measurement value DN, and the wind direction measurement value WD are started from the fixed station 8i via the data transmission / reception antenna 41p and the wireless transceiver 42p. The wind speed measurement value WV and the temperature T are received.
Then, by the gas concentration calculator 15 (see FIG. 2), the laser light measurement value DX, the background light measurement value DN, the reference gas concentration measurement value Do, the measurement section distance L, and the reference cell length from the storage unit 11 are stored. Based on Lo, the gas concentration C in the atmosphere is calculated and stored in the storage device 11 together with the data number j and the measurement date / time TMj (step S8).

In step S8, as shown in FIG. 7, first, the reference gas concentration measurement value Do from the reference photodiode 24 of the light source unit 20 is obtained (step S51).
In parallel or before and after this, the laser light measurement value DX measured by the measurement photodiode 45f from the fixed station 8i, the background light measurement value DN measured by the background light photodiode 46f, the wind direction measurement value WD, The wind speed measurement value WV and the temperature T are obtained (step S52).

Based on these data, the gas concentration C in the atmosphere is calculated by the following equation (step S53).
Atmospheric gas concentration C = {(laser light measurement value DX−background light measurement value DN) / reference gas concentration measurement value Do} × (reference cell length Lo / measurement section distance L) × reference cell gas concentration Co

  For example, in the example shown in FIG. 10, the density Di of the measurement line M1 connecting the laser light transmitting station 7 and each fixed station 8i is 0.1%, and the laser light transmitting station 7 is connected to each fixed station 8i + 1. The density Di + 1 of the measuring line M2 = 0.2%, the density Di + 2 of the measuring line M3 connecting the laser beam transmitting station 7 and each fixed station 8i + 2, and 0.15%, and the laser beam transmitting station 7 and each fixed station 8i + 3 The values of the concentration Di + 3 = 0.1% of the measurement line M4 connecting and the concentration Di + 4 = 0.1% of the measurement line M5 connecting the laser beam transmitting station 7 and each fixed station 8i + 4 are calculated.

  Thereafter, the position Pi of the fixed station 8 (the number i of the fixed station 8, the latitude xi, the longitude yi, the altitude Hi, and the measurement section distance to the fixed station 8 together with the data number j and the measurement date TMj. Li), laser light measurement value DXj (= DX), background light measurement value DNj (= DN), calculated atmospheric gas concentration Cj (= C), wind direction measurement value WDj (= WD), wind speed measurement value WVj ( = WV) and temperature Tj (= T) are stored in the storage 11 (step S54).

  And based on the data memorize | stored in the memory | storage device 11, as shown in FIG. 10, the measurement line M1 which connects the laser beam transmitting station 7 and the fixed station 8i (i = i-i + 4) to the display device 12 is shown. Each gas concentration Ci (i = i to i + 4) (i = j−α) in M5 is displayed (step S9).

It is determined whether or not the measurement has been completed (i = n) for all the fixed stations 8i (step S10). If not, the process returns to step S2, and the atmosphere is determined in steps S2 to S9 for the next fixed station 8i. The gas concentration C is calculated and the result is additionally displayed on the display 12.
Then, it is determined whether or not there is a fixed station 8i having an abnormal gas concentration Ci (step S11). If there is no fixed station 8i, the measurement is terminated (step S12).

On the other hand, if it is determined that there is a fixed station 8i having an abnormal gas concentration (step S11), the superimposed display creating device 17 (see FIG. 2) measures the wind direction measurement value WDj of the fixed station 8i having an abnormal gas concentration Cj. Based on the data of the wind speed measurement value WVj and the temperature Tj, the estimated gas ejection range Zi of the measured concentration is calculated.
That is, in the example illustrated in FIG. 10, it is determined that the fixed station 8i + 1 and the fixed station 8i + 2 are abnormal in the specified value.
Then, from the wind speed measurement value WVi + 1 and the wind speed measurement value WVi + 2 at the fixed station 8i + 1 and the fixed station 8i + 2, the upper limit lines M8 and M9 on the windward side of the concentration are obtained.
Further, surrounding limit lines M6 and M7 are obtained from the wind direction measurement value WDi + 1 and the wind direction measurement value WDi + 2.

In this way, the expected gas ejection range Zi + 1 with the gas concentration Ci = 0.2% is the measurement line M2 connecting the laser beam transmitting station 7 and each fixed station 8i + 1, the laser beam transmitting station 7 and each fixed station 8i. Is a range surrounded by a measurement line M1, an upper limit line M8, and a limit line M6.
Further, the expected gas ejection range Zi + 2 with the gas concentration Ci + 1 = 0.15% is a measurement line M3 connecting the laser light transmission station 7 and the fixed station 8i + 2, and a measurement line connecting the laser light transmission station 7 and the fixed station 8i + 1. The range is surrounded by M2, the upper limit line M9, and the limit line M7 (step S13).

  At this time, the vicinity of the laser beam transmitting station 7 of the measurement line M2 connecting the laser beam transmitting station 7 and the fixed station 8i + 1 is also included in the gas ejection assumed range Zi + 2 where the gas concentration = 0.15%. For the range, the gas concentration Ci on the windward side is selected.

Surrounded by the expected gas ejection range i + 1 with a gas concentration of 0.2% surrounded by the measurement line M1, the measurement line M2, the upper limit line M8 and the limit line M6, the measurement line M2, the measurement line M3, the upper limit line M9 and the limit line M7 In the assumed gas ejection range Zi + 2 with a gas concentration of 0.15%, as shown in FIG. 10, the gas concentration Ci on the windward side is selected for the overlapped range and is superimposed on the display 12 (step S14). ), And shifts to measurement by the mobile station 9 (step S15).
10 shows a part of the gas abnormality monitoring area 4, but all (n) fixed stations 8 around the gas abnormality monitoring area 4 are displayed. Alternatively, the entire display and the partial display may be selected and displayed.

(Measurement by mobile station)
Next, when an abnormality in the gas concentration is detected, as shown in FIG. 8, a mobile station 9 for receiving laser light is mounted on a moving body 69 such as a vehicle and measurement of the gas concentration is started ( Step S20).
First, a radio direction detecting radio wave is transmitted from the laser beam transmitting station 7 by the radio direction detecting radio wave transmitting antenna 38 and the radio direction detecting radio wave transmitter 39 (step S21).
On the other hand, when the preparation for measurement is completed, the mobile station 9 transmits information indicating that the position P (latitude x, longitude y) of the mobile station 9 and preparation for measurement are completed.

  The central control and monitoring apparatus 10 of the laser beam transmitting station 7 sends information indicating that the position P (latitude x, longitude y) and measurement preparation are completed from the mobile station 9 to the data transmission / reception antenna 41p and the wireless transceiver 42p. (Step S22).

In the central control and monitoring apparatus 10 of the laser beam transmission station 7, the received position P (latitude x) of the mobile station 9 is received by the topographic map collator 14 (see FIG. 2) based on the topographic map stored in the storage unit 11. , The height H (elevation) at longitude y) is calculated.
Then, from the relationship between the position P (latitude x, longitude y, altitude H) of the mobile station 9 and the position information Po (latitude xo, longitude yo, altitude Ho) of the light source unit 20, the distance L to the mobile station 9, The direction and the elevation angle are calculated (step S23).
Thereafter, as in the case of the fixed station 8, the data of the measurement photodiode 45m of the mobile station 9 is obtained by the first position scanning step S24a and the second position scanning step S24b (detailed processing is the same as in FIG. 6). The direction to the maximum specific position and the elevation angle are calculated, and the tilting drive unit 35 and the turning drive unit 36 are driven so that the front surface of the light source unit 20 is accurately directed to the specific position.

Next, as shown in FIG. 8, the measurement is started, and the laser beam measurement value DX, the background light measurement value DN, and the wind direction measurement value WD are started from the mobile station 9 via the data transmission / reception antenna 41p and the wireless transceiver 42p. The wind speed measurement value WV and the temperature T are received.
Then, the laser beam measurement value DX, the background light measurement value DN, the reference gas concentration measurement value Do from the reference photodiode 24 of the light source unit 20, the reference cell length Lo and the measurement section distance L from the storage device 11 Based on the above, the atmospheric gas concentration C is calculated and stored in the storage device 11 (step S25).

That is, as in the case of the fixed station 8, the gas concentration Ci in the atmosphere is calculated by the following equation by the processing in steps S51 to S54 shown in FIG.
Atmospheric gas concentration C = {(laser light measurement value DX−background light measurement value DN) / reference gas concentration measurement value Do} × (reference cell length Lo / measurement section distance L) × reference cell gas concentration Co

After that, the position Pj of the mobile station 9 (latitude x, longitude y, altitude H, measurement section distance L) of the mobile station 9, laser beam measurement value DXj (= DX) together with the new data number j and measurement date / time TMj ), Background light measurement value DNj (= DN), calculated atmospheric gas concentration Cj (= C), wind direction measurement value WDj (= WD), wind speed measurement value WVj (= WV), and temperature Tj (= T). And stored in the memory 11.
When the measurement is completed, a signal indicating that the measurement is completed is transmitted to the mobile station 9 via the wireless transceiver 42p and the data transmission / reception antenna 41p (step S26).

Then, based on the data stored in the storage device 11, as shown in FIG. 10, the gas concentration C in the atmosphere in the measurement line M <b> 10 connecting the laser light transmission station 7 and the mobile station 9 is displayed on the display device 12. An additional display is made (step S27).
Then, from the wind speed measurement value WVj in the mobile station 9, an upwind upper limit line M12 of the concentration is obtained.
Moreover, the surrounding limit line M11 is obtained from the wind direction measurement value WDj.
In the example illustrated in FIG. 10, the upper limit line M12 having a gas concentration of 0.15% is not used because it is upstream of the measurement line M1 having a gas concentration of 0.1%.

In this way, the expected gas ejection range of gas concentration = 0.15% measured by the mobile station 9 is excluded from the expected gas ejection range of gas concentration = 0.2% (gas concentration = 0.2%). The expected gas ejection range is narrowed) (step S28).
The calculation result is superimposed and displayed on the display 12 as shown in FIG. 10 (step S29).
Then, it is determined whether or not the measurement is finished (step S30). If not, the laser light receiving mobile station 9 is moved to the next measurement location, and the process returns to step S22.
Then, a new gas concentration C in the atmosphere is calculated at steps S22 to S29 for the next measurement location.
When the measurement is completed, the gas concentration distribution state is calculated and displayed based on various data stored in the storage device 11 (step S31), and the process is ended (step S32).

FIG. 11 shows the state of exploration in the emission direction from the laser beam transmission station 7 at this gas ejection point.
As shown in FIG. 11, when there is a gas ejection point between the laser beam transmitting station 7 and the fixed station 8, first, an abnormality in the gas concentration is detected at the fixed station 8.
Therefore, when the mobile station 9 performs measurement while moving from the laser beam transmission station 7 toward the fixed station 8, no abnormality in the gas concentration is detected in the vicinity of the laser beam transmission station 7.
And when it approaches the gas ejection point, the gas concentration increases, and after passing the gas ejection point, the gas concentration gradually decreases.
In this way, the gas ejection point is specified.

[Configuration of Laser Light Transmitting Station in Second Embodiment of the Present Invention]
Next, based on FIG. 12, the configuration of the laser beam transmitting station 7 constituted by the light source unit 20a, the gas injection / monitoring center 6 and the like in the second embodiment of the present invention will be described in detail.
FIG. 12 is a schematic diagram of a gas input / monitoring center provided with a light source unit in a gas concentration monitoring system according to a second embodiment of the present invention.
In FIG. 12, the same reference numerals as those in the first embodiment (see FIG. 2 etc.) of the present invention are the same members.

The difference from the first embodiment of the present invention is that, in addition to the turning tilt mechanism 30 for turning the light source unit 20a (see FIG. 2 and the like), a turning tilt mechanism 30a for fine driving is further added. In the point.
That is, the diameter of the concave mirror 51 of the fixed station 8 (or mobile station 9) for receiving laser light is about 1 to 2 m.
For example, in order to apply the laser beam R emitted from the light source unit 20a to the concave mirror 51 having a diameter of 1 to 2 m, the laser beam transmitting plate 50, and the measurement photodiodes 45f and 45m, which are installed 2 km away, Accurate position adjustment is required.

Therefore, as in the first embodiment of the present invention (see FIG. 2 etc.), a turning and tilting mechanism 30 is installed between the light source unit 20a and the pole 28, and in addition to this, the orientation of the mirror 22c and A turning and tilting mechanism 30a for changing the elevation angle is provided.
The turning tilt mechanism 30 for all directions turns and tilts the light source unit 20a so as to face the entire region of the gas abnormality monitoring area 4.
The fine tilting mechanism 30a for driving (or scanning) is, for example, a range twice as long as the horizontal scanning width b = 10 m and the vertical scanning height a = 10 m in the fixed station 8 or the mobile station 9. The mirror 22c is swiveled and tilted.

  According to the gas concentration monitoring system according to the second embodiment of the present invention having both the above-described omnidirectional turning tilt mechanism 30 and the fine driving (or scanning) turning tilt mechanism 30a, the following measurement points are provided. The turning drive to the fixed station 8 or the mobile station 9 is performed at high speed by the turning tilt mechanism 30 for all directions, and the scanning at a specific position is performed with high precision by the turning tilt mechanism 30a for fine driving (or scanning). It is.

[Configuration of Laser Light Transmitting Station in the Third Embodiment of the Present Invention]
Next, based on FIG. 13, the configuration of the laser beam transmitting station 7 constituted by the light source unit 20b, the gas injection / monitoring center 6 and the like in the third embodiment of the present invention will be described in detail.
FIG. 13 is a schematic diagram of a gas input / monitoring center provided with a light source unit in a gas concentration monitoring system according to a third embodiment of the present invention.
In FIG. 13, the same reference numerals as those in the first embodiment (see FIG. 2 etc.) of the present invention are the same members.

The difference from the first embodiment of the present invention is that a turning tilt mechanism 30b for fine driving is provided in place of the turning tilt mechanism 30 (see FIG. 2 and the like) that drives the light source unit 20 to turn. is there.
That is, the light source unit 20b is directly mounted on the pole 28.
A fine tilting tilt mechanism 30b is provided in the light source unit 20b for rotating and tilting the mirror 22c for irradiating the laser beam R so as to face the entire gas abnormality monitoring area 4.

According to the gas concentration monitoring system according to the third embodiment of the present invention including the above-described omnidirectional turning tilt mechanism 30b, the turning drive to the next measurement point (fixed station 8 or mobile station 9) is performed. Though slow, the scanning at the specific position is performed with high precision by the turning tilt mechanism 30a for fine driving (or scanning) as in the case of the second embodiment of the present invention.
In the third embodiment of the present invention, the illuminance meter 44p is not necessary. However, when the illuminance meter 44p is necessary, it is necessary to separately provide an illuminance meter turning drive mechanism.

[Overall Configuration in the Fourth Embodiment of the Present Invention]
Next, a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 14 is an overall layout diagram of a gas concentration monitoring system according to the fourth embodiment of the present invention.
The fourth embodiment of the present invention is different from the first embodiment of the present invention in that the mobile station 9 is not provided and only the fixed station 8 is arranged in the gas abnormality monitoring area 4. is there.

As shown in FIG. 14, at least one set of laser light transmission stations 7 a having light source units 20 (20 a, 20 b) is arranged at the center of the gas abnormality monitoring area 4 or at an appropriate place.
This laser beam transmission station 7a is similar to the laser beam transmission station 7 in the first to third embodiments (see FIGS. 2, 12, and 13), and includes a light source unit 20, a turning tilt mechanism 30 (and / or Or turning tilt mechanism 30a, turning tilt mechanism 30b), turning tilt control device 37, pole 28, LD driver unit 26, measurement unit 27, radio direction detecting radio wave transmitting antenna 38, radio direction detecting radio wave transmitter 39, wind direction and wind speed. It includes a total of 40p, a data transmission / reception antenna 41p, a wireless transceiver 42p, a thermometer 43p, an illuminance meter 44p, an AD converter AD, a DA converter DA, and the like.

As in the first embodiment of the present invention, a fixed station 8 for receiving laser light is installed at an appropriate position on the periphery of the gas abnormality monitoring area 4.
Further, a fixed station 8 for receiving a laser beam is appropriately installed in a depressed portion or a low portion where CO ₂ tends to stay in the gas abnormality monitoring area 4 as necessary.
In addition, a gas input / monitoring center 6a is installed at the periphery of the gas abnormality monitoring area 4 or at the location where the stored gas is received.
The gas input / monitoring center 6a includes a central control monitoring device 10 having a gas concentration calculator 15, a specific position scanner 16, and a superimposed display generator 17, as shown in FIG. 2, a storage device 11, a display device 12, and A keyboard 13 is provided.

  According to the gas concentration monitoring system according to the fourth embodiment of the present invention described above, the accuracy is coarser than that of the first embodiment of the present invention, but the first embodiment of the present invention. Since the gas concentration calculator 15, the specific position scanner 16, and the superimposed display generator 17 are included, the abnormal gas concentration in the atmosphere (air) is affected by the weather, particularly the wind direction and the wind speed. It can be analyzed and monitored with consideration.

As shown in FIG. 14, two sets of laser light transmitting stations 7 can be provided to specify the gas ejection point more accurately.
However, in this case, each fixed station 8 needs to provide two sets of the laser light transmitting plate 50, the concave mirror 51, the reflecting mirror 52, the measurement photodiode 45f, the background light photodiode 46f, etc., but the control monitoring device 47f The solar battery 53, the charging / discharging board 54, the secondary battery 55, the GPS antenna 56, the GPS receiver 57, the radio direction detector parabolic antenna 58, the radio direction detector 59, and the like can be shared.

[Configuration of transmission / reception data in the fifth embodiment of the present invention]
Next, the configuration of transmission / reception data between the gas input / monitoring center 6 (6a) and the fixed station 8 or the mobile station 9 will be described.
As described above, from the fixed station 8 to the gas input / monitoring center 6 (6a),
Laser light measurement value DX measured by measurement photodiode 45f, background light measurement value DN measured by background light photodiode 46f, wind direction measurement value WD and wind speed measurement value measured by wind direction anemometer 40f WV, temperature T measured by the thermometer 43f, and a signal indicating the presence or absence of a failure are transmitted.
In addition, from the mobile station 9 to the gas input / monitoring center 6 (6a),
Laser light measurement value DX measured by measurement photodiode 45m, background light measurement value DN measured by background light photodiode 46m, wind direction measurement value WD and wind speed measurement value measured by wind direction anemometer 40m The WV, the temperature T measured by the thermometer 43m, and the position (latitude x, longitude y) of the place where the mobile station 9 is measured, measured by the GPS receiver 57, are transmitted.

In this case, various data may be combined into one common transmission signal by time division.
This transmission signal has the following configuration.
a) Transmission signal start flag b) Laser beam measurement value DX
c) Background light measurement value DN
d) Wind direction measurement value WD
e) Wind speed measurement value WV
f) Temperature T
g) Existence of failure (blank for mobile station 9)
h) Latitude x (blank for fixed station 8)
i) Longitude y (blank for fixed station 8)
j) Transmission signal end flag

  As described above, by making the transmission signal from the fixed station 8 or the mobile station 9 to the gas input / monitoring center 6 (6a) into a common format, the management and operation of data are simplified.

[Other Embodiments]
The gas concentration monitoring system according to each embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and various modifications are made to the specific structure within the scope of the present invention. Needless to say, it is good.

For example, communication between the fixed station 8 or the mobile station 9 and the gas input / monitoring center 6 (6a) is not limited to wireless communication, and may be performed via a wire (electric wire or optical fiber cable). .
The fixed station and the mobile station are not provided with the measurement photodiode 45f and the background light photodiode 46f, but are provided with only a reflecting mirror, and the light source unit 20 is provided with the measurement photodiode 45f and the background light photodiode 46f. Anyway.

1 is an overall layout diagram of a gas concentration monitoring system according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of a gas input / monitoring center including the light source unit 20 illustrated in FIG. 1. FIG. 2 is a schematic diagram of a fixed station for receiving laser light illustrated in FIG. 1. It is a schematic diagram of the mobile station for laser beam reception shown in FIG. It is a control block diagram in the case of measurement by the fixed station in the central control monitoring apparatus shown in FIG. It is a specific detailed control block diagram of the specific position shown in FIG. FIG. 6 is a detailed control block diagram of the gas concentration detection / calculation shown in FIG. 5. It is a control block diagram in the case of the measurement by the mobile station in the central control monitoring apparatus shown in FIG. It is a figure which shows the method of pinpointing the specific position shown in FIG. It is a figure which shows the example of a display of the indicator shown in FIG. It is a schematic diagram which shows the method of pinpointing the position of the leakage gas which concerns on the 1st Embodiment of this invention. It is a schematic diagram of the gas supply and monitoring center provided with the light source unit in the gas concentration monitoring system which concerns on the 2nd Embodiment of this invention. It is a schematic diagram of the gas supply and monitoring center provided with the light source unit in the gas concentration monitoring system which concerns on the 3rd Embodiment of this invention. It is a whole layout figure of the gas concentration monitoring system concerning a 4th embodiment of the present invention. It is a whole block diagram of the conventional gas concentration measuring apparatus. It is a block diagram which shows the principal part of the gas concentration measuring apparatus shown in FIG. It is a perspective view which shows typically the gas concentration monitoring system by the conventional mobile body. It is a perspective view which shows typically the gas concentration monitoring system which installed the reflection part around the conventional. It is a conceptual diagram at the time of applying the conventional gas leak detection apparatus to an LNG storage base.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blocking aquifer 2 Quasi-fossil salt water layer 3 The ocean 4 Gas abnormality monitoring area 5 Gas injection piping 6, 6a Gas injection / monitoring center 7, 7a Laser beam transmitting station 8 (for receiving laser beam) Fixed station 9 Mobile station for optical reception 10 Central control and monitoring device 11 Storage device 12 Display device 13 Keyboard 14 Topographic map collator 15 Gas concentration calculator 16 Specific position scanner 17 Superimposed display generator 20, 20a, 20b Light source unit 21 LD module 22a mirror 22b half mirror 22c mirror 23 reference cell 24 reference photodiode 25 optical window 26 LD driver unit 27 measuring unit 28 pole 30, 30a, 30b turning tilt mechanism 31 horizontal shaft 32 vertical member 33 turning shaft 34 turntable 35 for tilting Drive unit 36 Drive unit 37 for turning 37 38 Radio direction detection radio wave transmission antenna 39 Radio direction detection radio wave transmission device 40p, 40f, 40m Wind direction anemometer 41p, 41f, 41m Data transmission / reception antenna 42p, 42f, 42m Wireless transceiver 43p, 43f, 43m Thermometer 44p, 44f, 44m Illuminance meter 45, 45f, 45m Measuring photodiode 46, 46f, 46m Background light photodiode 47f, 47m Control monitoring device 48 Shutter 49 Shutter driving device 50 Laser light transmitting plate 51 Concave mirror 52 Reflecting mirror 53 Solar cell 54 Charging / discharging panel 55 Secondary battery 56 GPS antenna 57 GPS receiver 58 Parabolic antenna for wireless azimuth detector 59 Wireless azimuth detector 60 Inclined shaft 61 Inclined axis driving device 62 Rotating shaft 63 Rotating driving device 64 Inclined slewing driving device 66f, 66m display Operation panel with power supply 67 Connector for power supply 68 Connector for signal line 69 Moving body 70 ＡＤ AD AD converter DA DA converter R Laser beam for measurement Lo Reference cell length L Measurement interval distance Lo Reference cell length Do Reference gas concentration measurement value j Data number TM Measurement date P Location information of fixed station i Fixed station number x Fixed station latitude y Fixed station longitude H Fixed station altitude xo Light source unit latitude yo Light source unit longitude Ho Light source unit altitude Measured wind direction at the WDo gas injection / monitoring center Measured wind speed at the WVO gas injection / monitoring center Toe Temperature at the gas injection / monitoring center WD Measured wind direction at the fixed station or mobile station WV Measured wind speed at the fixed station or mobile station T Fixed Temperature at the station or mobile station C Gas concentration in the atmosphere Co Gas in the reference cell Concentration DX laser light measurements DN background light measurement value M1~M5 measurement lines M6, M7 limit line M8, M9 upper line

Claims (18)

At least one light source unit having an LD module which is arranged in the gas abnormality monitoring area and emits laser light having an absorption wavelength specific to the gas to be measured toward the gas abnormality monitoring area;
A turning and tilting mechanism for controlling a light projection direction and an elevation angle of the laser light emitted from the light source unit;
It has a measurement photodiode that is arranged around the light source unit in the gas abnormality monitoring area and receives the laser light emitted from the light source unit , and the illuminance measured by the illuminance meter and the illuminance meter is a predetermined value. A plurality of fixed stations having shutters that close when exceeding
An anemometer installed in the fixed station;
A gas concentration calculator for calculating a gas concentration in the atmosphere between the light source unit and the fixed station based on a laser beam measurement value measured by the measurement photodiode of the fixed station, and an anemometer A central control monitoring device having a superimposed display creation device for calculating a gas ejection assumed range of the gas concentration calculated based on the measured wind direction value and the measured wind velocity value;
A storage device for storing the measurement value and the calculation result;
A gas concentration monitoring system comprising a display for displaying the calculation result. The light source unit is
The LD module;
A reference cell that encloses a gas to be measured at a predetermined gas concentration and transmits a part of light emission from the LD module;
A reference photodiode that receives the transmitted light transmitted through the reference cell;
The fixed station is
The gas concentration monitoring system according to claim 1, further comprising a background light photodiode at a position away from the measurement photodiode. The fixed station is
A control monitoring device that collects each measurement value measured by the measurement photodiode, the background light photodiode, and the anemometer, and generates and transmits a measurement value transmission signal;
An operation panel with indicator that can adjust each device and display the cause of failure,
The gas concentration monitoring system according to claim 2, comprising: The gas concentration monitoring system according to claim 2 or 3, wherein the gas concentration calculator of the central control monitoring device calculates the gas concentration C in the atmosphere by the following equation:
Atmospheric gas concentration C = {(laser light measurement value DX−background light measurement value DN) / reference gas concentration measurement value Do} × (reference cell length Lo / measurement section distance L) × reference cell gas concentration Co,
However,
Laser beam measurement value DX: Measurement value by measurement photodiode,
Background light measurement value DN: Measurement value by a background light photodiode,
Reference gas concentration measurement value Do: measurement value by reference photodiode,
Reference cell length Lo: length of reference cell,
Measurement section distance L: distance from the light source unit to the measurement photodiode,
Reference cell gas concentration Co: concentration of gas sealed in the reference cell.   The central control and monitoring device calculates the direction and elevation angle of the light source unit from the installation position of the fixed station and the installation position of the light source unit, and directs the light source unit toward the fixed station, and then the orientation and elevation angle of the light source unit. And a specified position calculator for specifying a position where the measured value of the laser beam from the measurement photodiode of the fixed station is maximized, within a predetermined scanning width and scanning height range. The gas concentration monitoring system according to any one of claims 1 to 4, wherein:   The central control monitoring device performs position specification by the specific position calculator at least twice in the predetermined scanning width and scanning height range and in a predetermined scanning width and scanning height range smaller than the predetermined scanning width and scanning height. 6. The gas concentration monitoring system according to claim 5, wherein the gas concentration monitoring system is one.   The superimposed display creation device of the central control monitoring device selects the gas concentration at the fixed station on the windward side when there are a plurality of the gas concentrations calculated at an arbitrary measurement point. The gas concentration monitoring system according to any one of claims 1 to 6. The fixed station is
It has a solar cell for generating electric power, a secondary battery for storing electric power, and a charge / discharge board for charging the secondary battery with electric power generated by the solar cell and supplying electric power to various devices in the fixed station The gas concentration monitoring system according to any one of claims 1 to 7. The fixed station is
The gas concentration monitoring system according to claim 1, further comprising a concave mirror for condensing the laser light from the light source unit and a reflecting mirror smaller than the concave mirror. Further, a measurement photodiode that is movably disposed in the gas abnormality monitoring area and receives the laser beam emitted from the light source unit, a background light photodiode installed at a position away from the measurement photodiode, and The gas concentration monitoring system according to claim 2, further comprising a mobile station for receiving laser light having an anemometer. The mobile station
A concave mirror for condensing the laser light from the light source unit and a reflective mirror smaller than the concave mirror;
An anemometer,
A parabolic antenna for detecting a direction of the light source unit and a wireless direction detector;
The gas concentration monitoring system according to claim 10 , comprising: The mobile station
The gas concentration monitoring system according to claim 10 or 11 , further comprising a GPS antenna and a GPS receiver for measuring an installation position of the mobile station. The mobile station
A control monitoring device that collects each measurement value measured by the measurement photodiode, the background light photodiode, the anemometer and the GPS receiver, and creates and transmits a measurement value transmission signal;
An operation panel with indicator that can adjust each device and display the cause of failure,
The gas concentration monitoring system according to claim 12 , comprising: The gas concentration according to any one of claims 10 to 13, wherein the gas concentration calculator of the central control monitoring device obtains the gas concentration in the atmosphere from the following equation for the mobile station. Monitoring system.
Atmospheric gas concentration C = {(laser light measurement value DX−background light measurement value DN) / reference gas concentration measurement value Do} × (reference cell length Lo / measurement section distance L) × reference cell gas concentration Co,
However,
Laser beam measurement value DX: Measurement value by measurement photodiode,
Background light measurement value DN: Measurement value by a background light photodiode,
Reference gas concentration measurement value Do: measurement value by reference photodiode,
Reference cell length Lo: length of reference cell,
Measurement section distance L: distance from the light source unit to the measurement photodiode,
Reference cell gas concentration Co: concentration of gas sealed in the reference cell. The specific position calculator of the central control monitoring device calculates the direction and elevation angle of the light source unit from the installation position of the mobile station and the installation position of the light source unit, and directs the light source unit to the mobile station, and then The position at which the laser beam measurement value from the measurement photodiode of the mobile station for receiving the laser beam is maximized by scanning within the range of the predetermined scanning width and scanning height in which the direction and elevation angle of the light source unit are set The gas concentration monitoring system according to any one of claims 10 to 14 , wherein the gas concentration monitoring system is specified. A measurement photodiode that receives the laser light emitted by the light source unit;
A concave mirror for condensing the laser light from the light source unit and a reflective mirror smaller than the concave mirror;
A background light photodiode installed at a position away from the measurement photodiode;
An anemometer that measures the wind speed of the surrounding wind direction,
A luminometer,
A shutter that closes when the illuminance measured by the illuminometer exceeds a predetermined value;
A control monitoring device that collects each measurement value measured by the measurement photodiode, the background light photodiode, and the anemometer, and generates and transmits a measurement value transmission signal;
A solar cell that generates electric power;
A secondary battery for storing electric power;
A charging / discharging panel for charging the power generated by the solar cell to the secondary battery and supplying power to various devices in the fixed station;
An operation panel with indicator that can adjust each device and display the cause of failure,
A fixed station for receiving laser light. A measurement photodiode that receives the laser light emitted by the light source unit;
A concave mirror for condensing the laser light from the light source unit and a reflective mirror smaller than the concave mirror;
A background light photodiode installed at a position away from the measurement photodiode;
An anemometer that measures the wind speed of the surrounding wind direction,
A luminometer,
A shutter that closes when the illuminance measured by the illuminometer exceeds a predetermined value;
A GPS antenna and GPS receiver for measuring the installation position;
A tilt-slewing drive device for controlling the direction and elevation angle of the measurement photodiode;
A control monitoring device that collects each measurement value measured by the measurement photodiode, the background light photodiode, the anemometer, and a GPS receiver, and generates and transmits a measurement value transmission signal;
An operation panel with indicator that can adjust each device and display the cause of failure,
A mobile station for receiving laser light. At least one light source unit having an LD module which is arranged in the gas abnormality monitoring area and emits laser light having an absorption wavelength specific to the gas to be measured toward the gas abnormality monitoring area;
A turning and tilting mechanism for controlling a light projection direction and an elevation angle of the laser light emitted from the light source unit;
It has a measurement photodiode and an anemometer that are arranged around the light source unit in the gas abnormality monitoring area and receives the laser light emitted from the light source unit, and is measured by an illuminometer and the illuminometer. A plurality of fixed stations for receiving laser light having a shutter that closes when the illuminance exceeds a predetermined value ;
A mobile station for receiving laser light, which is movably disposed in the gas abnormality monitoring area and has a measurement photodiode for receiving the laser light emitted by the light source unit and an anemometer, and
Always measure the gas abnormality by the fixed station,
A gas concentration measurement method comprising: measuring an abnormality of the gas by the mobile station for an upwind side of the fixed station where a gas abnormality is detected when a gas abnormality is detected.

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