CN113466164A - Gas detection device - Google Patents
Gas detection device Download PDFInfo
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- CN113466164A CN113466164A CN202110333530.8A CN202110333530A CN113466164A CN 113466164 A CN113466164 A CN 113466164A CN 202110333530 A CN202110333530 A CN 202110333530A CN 113466164 A CN113466164 A CN 113466164A
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- 238000001514 detection method Methods 0.000 title claims abstract description 95
- 238000004364 calculation method Methods 0.000 claims abstract description 21
- 230000003287 optical effect Effects 0.000 claims abstract description 11
- 238000011088 calibration curve Methods 0.000 claims description 51
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims description 38
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 28
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 238000005192 partition Methods 0.000 claims description 6
- 230000001678 irradiating effect Effects 0.000 claims description 5
- 239000007789 gas Substances 0.000 abstract description 257
- 238000012937 correction Methods 0.000 description 13
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 11
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 11
- 238000010521 absorption reaction Methods 0.000 description 10
- 239000003546 flue gas Substances 0.000 description 8
- 238000005259 measurement Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 5
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 2
- 229910001634 calcium fluoride Inorganic materials 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 230000002452 interceptive effect Effects 0.000 description 2
- 229910001120 nichrome Inorganic materials 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical compound S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
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- Spectroscopy & Molecular Physics (AREA)
- Biochemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
The invention provides a gas detection device capable of detecting the concentration of the 1 st gas with a simple structure. The device (1) is provided with: a light source (2) that irradiates Infrared (IF); a 1 st chamber (5) which is disposed on the optical path (LP) of the infrared ray (IF), and through which the infrared ray (IF) passes and through which a sample gas (GS0) containing a 1 st gas (GS1) that absorbs the infrared ray (IF) of the 1 st wavelength band passes; a 2 nd chamber (7) which is disposed on the optical path (LP), and which is filled with a 2 nd gas (GS2) that absorbs infrared rays (IF) of a 2 nd wavelength band that partially overlaps with the 1 st wavelength band, and through which the infrared rays (IF) pass; a light receiving amount detection unit (9) that receives infrared light (IF) that has passed through the 1 st chamber (5) and the 2 nd chamber (7) in this order and detects the amount of light received; a pressure detection unit (10) that detects the pressure in the 2 nd chamber (7); and a calculation unit that calculates the concentration of the 1 st gas (GS1) in the sample gas (GS0) on the basis of the amount of received light, and that corrects the concentration of the 1 st gas (GS1) on the basis of the pressure.
Description
Technical Field
The present invention relates to a gas detection device.
Background
A non-dispersive infrared absorption (NDIR) gas analyzer for measuring the concentration of sulfur dioxide, nitrogen oxide, and the like in flue gas is known (for example, see patent document 1). The gas analyzer described in patent document 1 includes: a light source for irradiating infrared rays, a sample cell and a compensation cell into which infrared rays are alternately incident, a detector for detecting the intensity of infrared rays, and an indicator for detecting the concentration of a gas component to be detected (e.g., sulfur dioxide).
The nitrogen gas which does not absorb infrared rays is sealed in the compensation tank, and the intensity of the infrared rays passing through the compensation tank is not attenuated. On the other hand, the measurement gas containing the target gas component may pass through the sample cell, and a part of the infrared rays transmitted therethrough is absorbed by the target gas component, whereby the intensity is attenuated. Hereinafter, a configuration in which the gas can be independently introduced into the sample cell and the compensation cell in this manner is referred to as a "two-system configuration". In addition, a compensation cell is provided to increase the stability of the continuous measurement (e.g., to reduce drift and ambient temperature variation effects).
Further, the gas analyzer described in patent document 1 includes an interference cell having 2 chambers. In the gas analyzer described in patent document 1, a differential pressure sensor can be provided between 2 chambers of the interference cell.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2003-014591
Disclosure of Invention
Technical problem to be solved by the invention
For example, when a gas containing sulfur dioxide and methane, in which the wavelength bands of infrared absorption overlap, is used as the measurement gas, it is conceivable to seal methane in an interference cell and use the gas analyzer described in patent document 1, but it may be difficult to accurately detect the concentration of sulfur dioxide.
The invention aims to provide a gas detection device capable of detecting the concentration of a 1 st gas by a simple structure.
Solution for solving the above technical problem
An aspect of the present invention relates to a gas detection device including: a light source for irradiating infrared rays; a 1 st chamber which is disposed on an optical path of infrared rays emitted from the light source, and through which the infrared rays pass, and through which a 1 st gas containing an infrared ray absorbing a 1 st wavelength band of the infrared rays passes; a 2 nd chamber which is disposed downstream of the 1 st chamber on the optical path, through which infrared rays pass, and filled with a 2 nd gas that absorbs infrared rays of a 2 nd wavelength band that partially overlaps with the 1 st wavelength band among the infrared rays; a light receiving amount detection unit that receives infrared rays that have passed through the 1 st chamber and the 2 nd chamber in this order and detects the amount of light received; a pressure detection unit that detects a pressure of the gas present in the 2 nd chamber; and a calculation unit that calculates a concentration of the 1 st gas in the sample gas based on the amount of received light, wherein the calculation unit corrects the concentration of the 1 st gas based on the pressure.
Effects of the invention
According to the present invention, the concentration of the 1 st gas in the sample gas can be accurately detected regardless of the magnitude of the concentration of the 2 nd gas in the sample gas. The gas detection device is not a two-system structure as described above, but a device having a simple configuration.
Drawings
Fig. 1 is a schematic configuration diagram showing a gas detection device 1 according to an embodiment of the present invention.
Fig. 2 is a block diagram of the gas detection apparatus shown in fig. 1.
Fig. 3 is an example of a calibration curve showing a relationship between the pressure in the 2 nd chamber and the concentration of the 2 nd gas contained in the sample gas.
Fig. 4 is an example of a calibration curve showing the relationship between the concentration of the 2 nd gas contained in the sample gas and the correction value with respect to the concentration of the 1 st gas calculated by the calculation unit.
Fig. 5 is a graph showing a 1 st wavelength band of infrared rays absorbed by a 1 st gas and a graph showing a 2 nd wavelength band of infrared rays absorbed by a 2 nd gas.
Fig. 6 is a schematic configuration diagram showing embodiment 2 of the gas detection apparatus of the present invention.
Fig. 7 is an example of a calibration curve showing a relationship between the pressure in the 2 nd chamber (effective value of pressure fluctuation) and the concentration of the 2 nd gas contained in the sample gas.
Fig. 8 is an example of a calibration curve showing the relationship between the concentration of the 2 nd gas contained in the sample gas and the correction value with respect to the concentration of the 1 st gas calculated by the calculation unit.
Detailed Description
Hereinafter, a gas detection device according to the present invention will be described in detail based on preferred embodiments shown in the drawings.
< embodiment 1 >
Hereinafter, embodiment 1 of the gas detection device of the present invention will be described with reference to fig. 1 to 5. For convenience of explanation, in fig. 1 (the same applies to fig. 6), X, Y, and Z axes orthogonal to each other are set, the XY plane is parallel to the horizontal plane, and the Z axis direction is parallel to the vertical direction. In fig. 1 (the same applies to fig. 6), the upper side is sometimes referred to as "upper", the lower side as "lower", the left side as "left", and the right side as "right". In addition, the calibration curves shown in fig. 3 and 4 are both schematic diagrams.
The gas detection device 1 shown in fig. 1 is "JISK 0151: 1983 "can measure the concentration of the 1 st gas GS1 contained in the sample gas GS0 as a specific gas by using the non-dispersive infrared absorption (NDIR) method.
The flue gas contains sulfur dioxide (SO) such as sulfur oxide2) In addition, Nitrogen Oxides (NO) are also includedX) And carbon monoxide (CO). In the present embodiment, the flue gas is used as the sample gas GS0, and the sulfur dioxide gas is used as the 1 st gas GS 1. Therefore, in the present embodiment, the gas detection device 1 is used as the sulfur dioxide concentration measurement device. In addition, in some cases, the flue gas may contain methane gas, and this methane gas is used as the 2 nd gas GS 2.
As shown in fig. 1, the gas detection device 1 includes: the light source 2, the fan 3, the rotation driving portion 4, the 1 st chamber 5, the 1 st gas supply portion 6, the 2 nd chamber 7, the 2 nd gas supply portion 8, the light receiving amount detection portion 9, the pressure detection portion 10, the operation portion 11, the display portion 12, and the control portion 13.
The light source 2 can irradiate the infrared rays IF toward the X-axis direction positive side. The light source 2 is not particularly limited, and for example, may be configured to be capable of irradiating infrared rays by including a nichrome wire and bringing the nichrome wire into an energized state.
The fan 3 is disposed on the X-axis direction positive side of the light source 2. The sector 3 is a switching unit for switching between irradiation (light projection) of infrared rays IF to the positive side in the X-axis direction and stop of the irradiation (light blocking). Sector 3 is formed of a disk-shaped member and has slit 31 at a position eccentric from the center thereof. Slit 31 is formed to penetrate fan-shaped surface 3 in the thickness direction (X-axis direction).
A rotation driving unit 4 is connected to the fan surface 3. The rotation driving unit 4 includes, for example, a motor. By operating the motor, fan 3 can be rotated around its center axis. Thus, the infrared rays IF pass through the slit 31 and are irradiated to the positive side of the X-axis direction in a state where the slit 31 faces the light source 2, that is, faces the light source 2. When fan 3 is rotated to move slit 31 away from light source 2, that is, when slit 31 is retracted, infrared IF is blocked and irradiation of infrared IF on the positive side in the X-axis direction is stopped.
On the X-axis direction positive side of sector 3, first chamber 5 is disposed. The 1 st chamber 5 has a chamber body 51, a supply port 52, and a discharge port 53.
The chamber main body 51 is disposed on an optical path LP along the X-axis direction of the infrared rays IF irradiated from the light source 2. The chamber body 51 is formed of, for example, a hollow rectangular parallelepiped, and has window portions 511 through which infrared rays IF pass, in a wall portion on the positive side and a wall portion on the negative side in the X axis direction that face each other through an internal space (space 512) thereof. Thus, the infrared rays IF can pass through (pass through) the chamber main body 51 in the order of the window 511 on the negative side in the X-axis direction, the space 512, and the window 511 on the positive side in the X-axis direction. The window 511 is preferably made of calcium fluoride (CaF)2) And the like.
A tubular supply port 52 is formed to protrude from the X-axis direction negative side of the chamber main body 51. The supply port 52 communicates with the space 512. The sample gas GS0 from the 1 st gas supply unit 6 can be supplied to the chamber main body 51 through the supply port 52.
A tubular discharge port 53 is formed to protrude from the X-axis direction positive side of the chamber main body 51. The discharge port 53 communicates with the space 512. The sample gas GS0 in the chamber main body 51 is exhausted through the exhaust port 53. Thus, the sample gas GS0 can pass through the chamber main body 51 from the supply port 52 toward the exhaust port 53, i.e., along the X-axis direction.
The 1 st gas supply unit 6 includes a supply source 61, a connection pipe 62, and a switching valve 63.
The supply source 61 has a tank filled with, for example, sample gas GS 0.
The connection pipe 62 connects the supply source 61 and the supply port 52 of the 1 st chamber 5. Thereby, the supply source 61 communicates with the 1 st chamber 5.
A switching valve 63 is provided in the middle of the connection pipe 62. The switching valve 63 opens and closes the connection pipe 62. In the open state, the sample gas GS0 in the supply source 61 can be supplied to the 1 st chamber 5. In the closed state, the supply of the sample gas GS0 to the 1 st chamber 5 can be stopped. The switching valve 63 may be omitted.
The 2 nd chamber 7 is disposed on the X-axis direction positive side of the 1 st chamber 5. The constitution of the 2 nd chamber 7 will be described later.
A light receiving amount detector 9 is disposed on the X-axis direction positive side of the 2 nd chamber 7. The light receiving amount detection section 9 has, for example, a photoconductive element. The photoconductive element can receive infrared rays IF passing through the chamber main body 51 of the 1 st chamber 5 and the chamber main body 71 of the 2 nd chamber 7 in this order. In the photoconductive element, the light receiving amount of the infrared IF can be detected by the photoconductive effect. The amount of light received by the infrared IF is stored in the storage unit 132 of the control unit 13. Since the infrared IF is non-dispersive, the light receiving and detecting unit 9 senses only the infrared absorption wavelength of the target gas component (component 1).
As shown in fig. 1, in the gas detection device 1, the light receiving amount detection unit 9, the control unit 13, the operation unit 11, and the display unit 12 are unitized to constitute a control unit 14.
As shown in fig. 2, the control unit 13 is electrically connected to the light source 2, the rotation driving unit 4, the 1 st gas supply unit 6, the 2 nd gas supply unit 8, the light receiving amount detection unit 9, the pressure detection unit 10, the operation unit 11, and the display unit 12, and can control the operations of the respective units. The control unit 13 includes a CPU131 and a storage unit 132. The CPU131 can execute a control program stored in advance in the storage unit 132, for example. The CPU131 also has a function as a calculation unit 133, and the calculation unit 133 calculates the concentration of the 1 st gas GS1 in the sample gas GS0 based on the amount of received infrared light IF detected by the amount-of-received-light detection unit 9. The storage unit 132 can store various information such as a control program and a calibration curve CC1 (see fig. 3) and a calibration curve CC2 (see fig. 4) described later.
The operation unit 11 is a part that receives an input from a user who operates the gas detection device 1 and uses the gas detection device. The operation unit 11 is not particularly limited, and examples thereof include a keyboard and a mouse.
The display unit 12 can display, for example, the measurement conditions when measuring the concentration of the 1 st gas GS1, and can also display the concentration of the 1 st gas GS1 and the like. The display unit 12 is not particularly limited, and may be formed of, for example, liquid crystal, organic EL, or the like.
As described above, in the present embodiment, the flue gas is used as the sample gas GS0, and the sulfur dioxide gas contained in the flue gas is used as the 1 st gas GS 1. In addition, in some cases, the flue gas may contain methane gas, and this methane gas is used as the 2 nd gas GS 2.
As shown in fig. 5, the 1 st gas GS1 has a characteristic of absorbing the 1 st wavelength band of infrared rays IF. When the 1 st gas GS1 is sulfur dioxide gas, the 1 st gas GS1 absorbs infrared IF having a wavelength in the range before and after the peak of absorption, which is infrared IF having a wavelength of 7.4 μm.
Further, the 2 nd gas GS2 has a characteristic of absorbing the 2 nd wavelength band infrared ray IF which partially overlaps with the 1 st wavelength band among the infrared ray IF. When the 2 nd gas GS2 is methane gas, the 2 nd gas GS2 absorbs infrared rays IF having wavelengths in the range before and after the peak of absorption, which is infrared rays IF having a wavelength of 7.6 μm.
In the overlapping wavelength band where the 1 st wavelength band and the 2 nd wavelength band overlap, the peak wavelength of the infrared IF absorbed most by the 1 st gas GS1 and the peak wavelength of the infrared IF absorbed most by the 2 nd gas GS2 are included. In addition, although the peak wavelengths are included in the overlapping wavelength band in the present embodiment, the peak wavelengths are not limited to this, and may be deviated from the overlapping wavelength band depending on the types of the 1 st gas GS1 and the 2 nd gas GS2, for example.
The light receiving amount detector 9 detects the amount of light received by the infrared IF based on the magnitude of the amount of absorption by the infrared IF. For example, in the case where the absorption amount is large, the light receiving amount is detected to be small. Conversely, when the absorption amount is small, the light receiving amount is detected to be large.
The concentration of the 1 st gas GS1 in the sample gas GS0 is calculated by the calculation unit 133 based on the amount of light received by the infrared IF.
When the 2 nd gas GS2 is mixed with the sample gas GS0, the overlapping wavelength band of the infrared rays IF is absorbed by the 2 nd gas GS2 in addition to the 1 st gas GS1 in the 1 st chamber 5. Therefore, the light receiving amount in the light receiving amount detecting section 9 is also detected by being affected by the absorption of the No. 2 gas GS 2. As a result, the concentration (actually measured value) of the 1 st gas GS1 calculated based on the amount of received light also includes the concentration of the 2 nd gas GS2, and a corresponding error occurs, which is not correct.
Further, when the gas detection device 1 has the above-described two-system configuration, the device configuration of the gas detection device 1 becomes correspondingly complicated.
Thus, the gas detection device 1 is configured to eliminate such a failure. The following describes the structure and operation. Hereinafter, a portion including the 2 nd chamber 7, the 2 nd gas supply unit 8, and the pressure detection unit 10 may be referred to as "the correction unit 15".
The 2 nd chamber 7 is disposed between the 1 st chamber 5 and the light receiving amount detection unit 9. The 2 nd chamber 7 has a chamber main body 71 and a supply port 72. The 2 nd chamber 7 may be in a sealed state filled with the 2 nd gas GS2 in advance. The chamber main body 71 is disposed on the downstream side, i.e., the X-axis direction positive side, of the chamber main body 51 of the 1 st chamber 5 on the light path LP. The chamber body 71 is formed of, for example, a hollow rectangular parallelepiped.
The 2 nd chamber 7 includes a partition portion 74 that partitions the interior of the chamber main body 71 (the 2 nd chamber 7) into 2 spaces, and a communication portion 75 that communicates the 2 spaces. Hereinafter, one (lower) space of the 2 spaces is referred to as "1 st space 712", and the other (upper) space is referred to as "2 nd space 713". The partition 74 has a plate shape, and the communication portion 75 is formed of a through hole that penetrates the partition 74 in the thickness direction (Z-axis direction).
The chamber main body 71 has a window 711 through which infrared IF passes, in a wall on the positive side and a wall on the negative side in the X-axis direction that face each other through the 1 st space 712. Thus, the infrared rays IF can pass through the chamber main body 71 in the order of the window 711 on the negative side in the X-axis direction, the 1 st space 712, and the window 711 on the positive side in the X-axis direction. The window 711 is preferably made of calcium fluoride or the like, as in the case of the window 511.
In addition, the cross-sectional shape of the 1 st space 712 along the Y-axis direction is preferably the same as the cross-sectional shape of the space 512 in the 1 st chamber 5 along the Y-axis direction, and the cross-sectional area S712 of the 1 st space 712 and the cross-sectional area S512 of the space 512 are preferably the same. This enables the infrared IF to sufficiently reach the light receiving amount detection unit 9.
The 2 nd space 713 is smaller in volume than the 1 st space 712, and the pressure detecting unit 10 is disposed. By disposing the pressure detection unit 10 in the 2 nd space 713, the pressure detection unit 10 can be prevented from interfering with the infrared IF when the infrared IF passes through the 1 st space 712. This allows the light-receiving amount detection unit 9 to sufficiently receive the infrared IF.
A tubular supply port 72 is formed to protrude from the X-axis direction negative side of the chamber main body 71. The supply port 72 communicates with the 2 nd space 713. The 2 nd gas GS2 from the 2 nd gas supply unit 8 can be supplied into the chamber main body 71 through the supply port 72. Thus, the 2 nd gas GS2 can be filled into the chamber main body 71, i.e., the 1 st space 712 and the 2 nd space 713.
The 2 nd gas supply unit 8 includes a supply source 81, a connection pipe 82, and a switching valve 83.
The supply source 81 has a tank filled with, for example, the 2 nd gas GS 2.
The connection pipe 82 connects the supply source 81 and the supply port 72 of the 2 nd chamber 7. Thereby, the supply source 81 communicates with the 2 nd chamber 7.
A switching valve 83 is provided in the middle of the connection pipe 82. The switching valve 83 opens and closes the connection pipe 82. In the on state, the 2 nd gas GS2 in the supply source 81 can be supplied to the 2 nd chamber 7. In the closed state, the supply of the 2 nd gas GS2 to the 2 nd chamber 7 can be stopped.
In addition, although the gas detection device 1 has the configuration including the 2 nd gas supply unit 8 in the present embodiment, the configuration is not limited to this, and for example, the configuration may be such that the 2 nd gas supply unit 8 (supply port 72) is omitted. In this case, the 2 nd chamber 7 is sealed and filled with the 2 nd gas GS2 in advance.
The pressure detection unit 10 is disposed in the 2 nd space 713 of the 2 nd chamber 7. The pressure detection unit 10 detects the pressure of the gas present in the 2 nd chamber 7 (hereinafter, simply referred to as "pressure" or "pressure in the 2 nd chamber 7"). This pressure is actually a valid value of the pressure change.
As shown in fig. 2, the pressure detection unit 10 includes a piezoelectric conversion unit 101 that detects the change in pressure. The piezoelectric transducer 101 is not particularly limited, and examples thereof include sensors such as a condenser microphone (condenser microphone) and a flow sensor (comb-shaped heat ray micro sensor).
When the infrared ray IF is irradiated from the light source 2 and passes through the 2 nd chamber 7, the 2 nd gas GS2 as methane gas absorbs the infrared ray IF of the 2 nd wavelength band in the 2 nd chamber 7. As a result, the temperature in the 2 nd chamber 7 rises and the pressure rises, that is, the pressure changes. The pressure detection unit 10 can detect the amount of change in pressure by the piezoelectric conversion unit 101, and accurately detect the pressure in the 2 nd chamber 7 when infrared rays are irradiated.
The length LX512 in the X-axis direction in the space 512 of the 1 st chamber 5 is preferably about 200mm, for example. The length LX712 along the X-axis direction (light path LP) in the 1 st space 712 of the 2 nd chamber 7 is preferably 5mm to 50 mm.
Further, the concentration of the 2 nd gas GS2 in the 2 nd chamber 7 is preferably 20g/Nm3Above 700g/Nm3Hereinafter, more preferably 40g/Nm3Above 300g/Nm3The following.
According to the above numerical range, when the infrared ray IF passes through the 2 nd chamber 7, the 2 nd gas GS2 in the 2 nd chamber 7 can absorb the infrared ray IF of the 2 nd wavelength band as much as possible. This enables the pressure in the 2 nd chamber 7 to be changed to such an extent that the pressure in the 2 nd chamber 7 can be detected more accurately.
The storage unit 132 stores a calibration curve CC1 shown in fig. 3 and a calibration curve CC2 shown in fig. 4 in advance.
The calibration curve CC1 is a graph showing the relationship between the pressure (effective value of pressure fluctuation) in the 2 nd chamber 7 and the concentration of the 2 nd gas GS2 contained in the sample gas GS0, that is, in the 1 st chamber 5. As previously mentioned, the calibration curve CC1 is merely a schematic diagram. In addition, the base value (base) of the pressure in the 2 nd chamber 7 tends to be constant (typically atmospheric pressure). The frequency of the intermittent irradiation with infrared IF (infrared light) is varied slightly at the same frequency. When the concentration of the 2 nd gas GS2 in the 1 st chamber 5 becomes high, the amplitude (effective value) of the minute fluctuation of the pressure becomes small.
The calibration curve CC2 is a graph showing the relationship between the concentration of the 2 nd gas GS2 contained in the sample gas GS0 and the correction value with respect to the concentration (measured value) of the 1 st gas GS 1.
The calibration curves CC1 and CC2 are obtained in advance by, for example, experiments or simulations.
Note that the calibration curves CC1 and CC2 are graphs in the present embodiment, but are not limited to these, and may be tables, mathematical expressions, or the like, for example.
The calculation unit 133 calculates the concentration of the 1 st gas GS1 in the sample gas GS0 based on the amount of light received by the infrared IF detected by the light-receiving amount detection unit 9.
As described above, when the sample gas GS0 (flue gas) is mixed with the 2 nd gas GS2 (methane gas), there is a possibility that an error occurs in the measured value of the concentration of the 1 st gas GS1 based on the amount of received light. The calculation unit 133 can correct the density to a correct density by eliminating the error.
Specifically, the calculation unit 133 corrects the concentration of the 1 st gas GS1 based on the pressure. In particular, in the present embodiment, the calculation unit 133 corrects the concentration of the 1 st gas GS1 based on the calibration curve CC1 and the calibration curve CC 2.
In the gas detection device 1, first, the concentration of the 1 st gas GS1 is temporarily calculated based on the amount of light received by the light-receiving amount detection unit 9. This enables the concentration of the 1 st gas GS1 to be measured.
At this time, the pressure in the 2 nd chamber 7 is detected by the pressure detecting unit 10. The calculation unit 133 obtains the concentration of the 2 nd gas GS2 corresponding to the pressure detected by the pressure detection unit 10 using the calibration curve CC 1. For example, as shown in fig. 3, when the pressure detected by the pressure detector 10 is "pressure P", the concentration of the 2 nd gas GS2 can be obtained as "concentration Q" from the calibration curve CC 1.
Next, the calculation unit 133 obtains a correction value of the concentration of the 1 st gas GS1 corresponding to the concentration of the 2 nd gas GS2 obtained above, using the calibration curve CC 2. For example, as shown in fig. 4, when the concentration of the 2 nd gas GS2 is "concentration Q", a correction value can be obtained as "correction value R" from the calibration curve CC 2.
Next, the calculation unit 133 calculates a value obtained by reflecting the correction value R in the actual measurement value of the concentration of the 1 st gas GS1, that is, a value obtained by addition. Thereby, the concentration of the 1 st gas GS1 is corrected to a correct value. Then, the corrected concentration of the 1 st gas GS1 is displayed on the display unit 12. This enables to confirm the correct concentration of the 1 st gas GS 1.
For example, the sample gas GS0 contains the sample gas with the concentration of 26mg/Nm3And further mixed with sulfur dioxide gas (No. 1 gas GS1) at a concentration of 300mg/Nm3The experimental example in the case of the methane gas (GS2 No. 2) of (1) will be described. The concentration of sulfur dioxide gas and the concentration of methane gas in the sample gas GS0 are known.
In the case where the gas detection device 1 is used, the concentration of the sulfur dioxide gas is detected to be 26mg/Nm3. The detection result is the same as the known value.
On the other hand, in the case where the correction unit 15 is omitted from the gas detection device 1, the concentration of the sulfur dioxide gas is detected as 66mg/Nm3. The detection results deviate significantly from the known values.
As described above, the gas detection apparatus 1 can accurately detect the concentration of the 1 st gas GS1 in the sample gas GS0 by the calibration unit 15 regardless of the magnitude of the concentration of the 2 nd gas GS2 in the sample gas GS 0. The gas detection device 1 is not a two-system structure, but a device having a simple configuration.
< embodiment 2 >
Hereinafter, embodiment 2 of the gas detection apparatus according to the present invention will be described with reference to fig. 6 to 8, and the differences from the above-described embodiments will be mainly described, and the description of the same matters will be omitted.
This embodiment is the same as embodiment 1 except for the configuration of the correction means.
As shown in fig. 6, in the present embodiment, the 2 nd chamber 7 further includes a discharge port 73 in addition to the chamber main body 71 and the supply port 72.
The discharge port 73 is tubular and is formed to protrude from the X-axis direction negative side of the chamber main body 71. The discharge port 73 communicates with the 2 nd space 713.
The calibration unit 15 (gas detection device 1) is provided with an adjustment unit 16 that adjusts the concentration of the 2 nd gas GS2 in the 2 nd chamber 7. The adjusting section 16 includes a connecting pipe 161 and a switching valve 162.
The connection pipe 161 is connected to the discharge port 73. Thereby, the connection pipe 161 and the chamber main body 71 communicate with each other through the discharge port 73.
A switching valve 162 is provided in the middle of the connection pipe 161. The switching valve 162 opens and closes the connection pipe 161. By adjusting the opening degree of the switching valve 162, the 2 nd gas GS2 in the chamber main body 71 can be discharged from the connection pipe 161, and the chamber main body 71 can be opened to the atmosphere. This makes it possible to adjust the concentration of the 2 nd gas GS2 in stages (for example, in 3 stages).
The storage unit 132 stores a calibration curve CC1-1, a calibration curve CC1-2, and a calibration curve CC1-3 shown in fig. 7, a calibration curve CC2-1, a calibration curve CC2-2, and a calibration curve CC2-3 shown in fig. 8.
The calibration curves CC1-1 to CC1-3 are graphs showing the relationship between the pressure in the 2 nd chamber 7 and the concentration of the 2 nd gas GS2 contained in the sample gas GS0, i.e., in the 1 st chamber 5, and are used separately according to the magnitude of the concentration of the 2 nd gas GS 2.
The calibration curves CC2-1 to CC2-3 are graphs showing the relationship between the concentration of the 2 nd gas GS2 contained in the sample gas GS0 and the correction value with respect to the concentration (measured value) of the 1 st gas GS1, and are used separately according to the magnitude of the concentration of the 2 nd gas GS2, similarly to the calibration curves CC1-1 to CC 1-3.
When the concentration of the 1 st gas GS1 is detected, for example, when the calibration curve CC1-1 is used, the calibration curve CC2-1 is used. In addition, when the calibration curve CC1-2 was used, the calibration curve CC2-2 was used. In addition, when the calibration curve CC1-3 was used, the calibration curve CC2-3 was used.
In this manner, in the gas detection apparatus 1, 1 of the calibration curves CC1-1 to CC1-3 and 1 of the calibration curves CC2-1 to CC2-3 can be selected and used according to the concentration of the 2 nd gas GS 2. This enables more accurate detection of the concentration of the 1 st gas GS 1.
The gas detection device of the present invention has been described above with reference to the illustrated embodiments, but the present invention is not limited thereto, and the respective portions constituting the gas detection device may be replaced with any configuration that can exhibit the same function.
In addition, any structure may be added. The gas detection device of the present invention may be a device obtained by combining 2 or more arbitrary configurations (features) of the above embodiments.
In the above embodiments, the sulfur dioxide gas is exemplified as the 1 st gas GS1, and the methane gas is exemplified as the 2 nd gas GS2, but the present invention is not limited thereto. For example, nitrogen oxide or carbon monoxide may be used as the 1 st gas GS1, and carbon dioxide may be used as the 2 nd gas GS 2.
The 1 st chamber 5 may be configured to continuously circulate the sample gas to the chamber main body 51 by pumping the sample gas GS 0.
In addition, the positional relationship between the 1 st chamber 5 and the 2 nd chamber 7 is a relationship in which the 1 st chamber 5 is disposed on the upstream side and the 2 nd chamber 7 is disposed on the downstream side in the above embodiment, but the positional relationship is not limited to this, and for example, the relationship may be such that the 2 nd chamber 7 is disposed on the upstream side and the 1 st chamber 5 is disposed on the downstream side.
[ solution ]
Those skilled in the art will appreciate that the various exemplary embodiments described above are specific examples of the following arrangements.
The gas detection device according to the first aspect of (item 1) includes:
a light source for irradiating infrared rays;
a 1 st chamber which is disposed on an optical path of infrared rays emitted from the light source, and through which the infrared rays pass, and through which a 1 st gas containing an infrared ray absorbing a 1 st wavelength band of the infrared rays passes;
a 2 nd chamber disposed on the optical path, through which the infrared ray passes, and filled with a 2 nd gas absorbing an infrared ray of a 2 nd wavelength band partially overlapping with the 1 st wavelength band among the infrared rays;
a light receiving amount detector for receiving infrared rays sequentially passing through the 1 st chamber and the 2 nd chamber and detecting a light receiving amount thereof;
a pressure detection unit that detects a pressure of the gas present in the 2 nd chamber;
a calculation unit that calculates the concentration of the 1 st gas in the sample gas based on the amount of received light,
the calculation unit corrects the concentration of the 1 st gas based on the pressure.
According to the gas detection apparatus described in item 1, the concentration of the 1 st gas in the sample gas can be accurately detected regardless of the magnitude of the concentration of the 2 nd gas in the sample gas. The gas detection device is not a two-system structure as described above, but a device having a simple configuration.
(item 2) in the gas detection device according to item 1,
a storage unit for storing a calibration curve showing a relationship between the pressure and a concentration of the 2 nd gas contained in the sample gas,
the calculation unit corrects the concentration of the 1 st gas based on the calibration curve.
According to the gas detection apparatus described in item 2, the concentration of the 1 st gas can be accurately detected with a simple configuration using a calibration curve.
(item 3) the gas detection device according to item 1 or 2,
the 2 nd chamber has: a partition part for dividing the 2 nd chamber into 2 spaces; and a communicating portion communicating the 2 spaces,
one of the 2 spaces is through which infrared rays pass, and the pressure detection unit is disposed in the other space.
According to the gas detection device described in item 3, since the pressure detection unit can be prevented from interfering with the infrared ray when the infrared ray passes through one of the spaces, the infrared ray can be sufficiently received by the light receiving amount detection unit.
(item 4) the gas detection device according to any one of items 1 to 3,
the length along the optical path in the 2 nd chamber is 5mm to 50 mm.
According to the gas detection apparatus described in item 4, when the infrared ray passes through the 2 nd chamber, the 2 nd gas in the 2 nd chamber can absorb the infrared ray of the 2 nd wavelength band without much or little. This enables the pressure in the 2 nd chamber to be changed to such an extent that the pressure in the 2 nd chamber can be detected more accurately.
(claim 5) the gas detection device according to any one of claims 1 to 4,
the concentration of the 2 nd gas in the 2 nd chamber is 20g/Nm3Above 700g/Nm3The following.
According to the gas detection apparatus described in claim 5, when the infrared ray passes through the 2 nd chamber, the 2 nd gas in the 2 nd chamber can absorb the infrared ray of the 2 nd wavelength band without much or little. This enables the pressure in the 2 nd chamber to be changed to such an extent that the pressure in the 2 nd chamber can be detected more accurately.
(item 6) the gas detection device according to any one of items 1 to 5,
the pressure detection unit has a piezoelectric conversion unit for detecting the change in the pressure.
According to the gas detection device described in item 6, the pressure can be accurately detected with a simple configuration using the piezoelectric conversion unit.
(item 7) the gas detection device according to any one of items 1 to 6,
an adjusting part for adjusting the concentration of the 2 nd gas in the 2 nd chamber is provided.
According to the gas detection apparatus described in the item 7, for example, the calibration curve can be used separately according to the magnitude of the concentration of the 2 nd gas.
(item 8) the gas detection device according to any one of items 1 to 7,
the 1 st gas is sulfur dioxide gas, and the 2 nd gas is methane gas.
The gas detection device according to claim 8, wherein the gas detection device is used as a sulfur dioxide concentration measurement device for measuring a concentration of the sulfur dioxide gas.
Description of the reference numerals
1 gas detection device
2 light source
3 sectors
31 slit
4 rotary driving part
51 st Chamber
51 chamber body
511 window part
512 space
52 supply port
53 discharge port
6 st gas supply section
61 supply source
62 connecting pipe
63 switching valve
7 nd 2 nd chamber
71 chamber body
711 Window part
712 1 st space
713 nd 2 nd space
72 supply port
73 discharge port
74 divider
75 communicating part
8 nd 2 nd gas supply part
81 supply source
82 connecting pipe
83 switching valve
9 light receiving amount detecting section
10 pressure detecting part
101 piezoelectric conversion part
11 operating part
12 display part
13 control part
131 CPU
132 storage unit
133 arithmetic unit
14 control unit
15 correction unit
16 adjustment part
161 connecting pipe
162 switching valve
CC1 calibration Curve
CC1-1 calibration Curve
CC1-2 calibration Curve
CC1-3 calibration Curve
CC2 calibration Curve
CC2-1 calibration Curve
CC2-2 calibration Curve
CC2-3 calibration Curve
GS0 sample gas
GS1 gas No. 1
IF infrared ray
LP light path
LX512 Length
LX712 Length
Pressure P
Concentration of Q
R correction value
S512 cross sectional area
S712 cross-sectional area.
Claims (8)
1. A gas detection device is characterized by comprising:
a light source for irradiating infrared rays;
a 1 st chamber which is disposed on an optical path of infrared rays emitted from the light source, and through which the infrared rays pass, and through which a 1 st gas containing an infrared ray absorbing a 1 st wavelength band of the infrared rays passes;
a 2 nd chamber disposed on the optical path, through which the infrared ray passes, and filled with a 2 nd gas absorbing an infrared ray of a 2 nd wavelength band partially overlapping with the 1 st wavelength band among the infrared rays;
a light receiving amount detector for receiving infrared rays sequentially passing through the 1 st chamber and the 2 nd chamber and detecting a light receiving amount thereof;
a pressure detection unit that detects a pressure of the gas present in the 2 nd chamber;
a calculation unit that calculates the concentration of the 1 st gas in the sample gas based on the amount of received light,
the calculation unit corrects the concentration of the 1 st gas based on the pressure.
2. The gas detection apparatus of claim 1,
a storage unit for storing a calibration curve showing a relationship between the pressure and a concentration of the 2 nd gas contained in the sample gas,
the calculation unit corrects the concentration of the 1 st gas based on the calibration curve.
3. The gas detection apparatus according to claim 1 or 2,
the 2 nd chamber has: a partition part for dividing the 2 nd chamber into 2 spaces; and a communicating portion communicating the 2 spaces,
one of the 2 spaces is through which infrared rays pass, and the pressure detection unit is disposed in the other space.
4. The gas detection apparatus according to any one of claims 1 to 3, wherein a length along the optical path in the 2 nd chamber is 5mm or more and 50mm or less.
5. The gas detection apparatus according to any one of claims 1 to 4, wherein a concentration of the 2 nd gas in the 2 nd chamber is 20g/Nm3Above 700g/Nm3The following.
6. The gas detection device according to any one of claims 1 to 5, wherein the pressure detection unit has a piezoelectric conversion unit that detects the change in the pressure.
7. The gas detection apparatus according to any one of claims 1 to 6, comprising an adjustment unit that adjusts a concentration of the 2 nd gas in the 2 nd chamber.
8. The gas detection device according to any one of claims 1 to 7, wherein the 1 st gas is a sulfur dioxide gas, and the 2 nd gas is a methane gas.
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| JP2020-059612 | 2020-03-30 | ||
| JP2020059612A JP7388269B2 (en) | 2020-03-30 | 2020-03-30 | gas detection device |
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Cited By (1)
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| CN117250166A (en) * | 2023-09-21 | 2023-12-19 | 江苏舒茨测控设备股份有限公司 | Non-spectroscopic infrared gas detection method and sensor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102007397A (en) * | 2008-04-15 | 2011-04-06 | 株式会社岛津制作所 | Gas analyzing apparatus with built-in calibration gas cell |
| CN106501192A (en) * | 2015-09-08 | 2017-03-15 | 富士电机株式会社 | Gas analyser |
| CN206300896U (en) * | 2016-10-28 | 2017-07-04 | 株式会社岛津制作所 | Sulfur dioxide measurement apparatus |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012068164A (en) * | 2010-09-24 | 2012-04-05 | Horiba Ltd | Infrared gas analyzer |
| WO2020059100A1 (en) | 2018-09-21 | 2020-03-26 | 大塚電子株式会社 | Measuring device and measuring method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102007397A (en) * | 2008-04-15 | 2011-04-06 | 株式会社岛津制作所 | Gas analyzing apparatus with built-in calibration gas cell |
| CN106501192A (en) * | 2015-09-08 | 2017-03-15 | 富士电机株式会社 | Gas analyser |
| CN206300896U (en) * | 2016-10-28 | 2017-07-04 | 株式会社岛津制作所 | Sulfur dioxide measurement apparatus |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117250166A (en) * | 2023-09-21 | 2023-12-19 | 江苏舒茨测控设备股份有限公司 | Non-spectroscopic infrared gas detection method and sensor |
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| JP2021156813A (en) | 2021-10-07 |
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