CN117388201B - Gas concentration detection method and system - Google Patents
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- CN117388201B CN117388201B CN202311681277.0A CN202311681277A CN117388201B CN 117388201 B CN117388201 B CN 117388201B CN 202311681277 A CN202311681277 A CN 202311681277A CN 117388201 B CN117388201 B CN 117388201B
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- 238000001514 detection method Methods 0.000 title claims abstract description 202
- 238000012937 correction Methods 0.000 claims abstract description 112
- 238000000034 method Methods 0.000 claims abstract description 32
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims description 108
- 230000003287 optical effect Effects 0.000 claims description 9
- 238000002835 absorbance Methods 0.000 claims description 5
- 239000000126 substance Substances 0.000 abstract description 4
- 239000007789 gas Substances 0.000 description 180
- 239000012855 volatile organic compound Substances 0.000 description 22
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 9
- 239000002245 particle Substances 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000010521 absorption reaction Methods 0.000 description 5
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- YNQLUTRBYVCPMQ-UHFFFAOYSA-N Ethylbenzene Chemical compound CCC1=CC=CC=C1 YNQLUTRBYVCPMQ-UHFFFAOYSA-N 0.000 description 2
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 239000008096 xylene Substances 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 238000000862 absorption spectrum Methods 0.000 description 1
- 235000013405 beer Nutrition 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004737 colorimetric analysis Methods 0.000 description 1
- 238000005034 decoration Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000835 electrochemical detection Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
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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
- G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light
-
- 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
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
Abstract
The invention discloses a gas concentration detection method and system, and relates to the technical field of gas concentration detection. The method comprises the following steps: the light intensity of the light source under the conditions of clean air and gas to be detected is detected by utilizing the light detector; the light source is a correction light source or a detection light source; determining a correction coefficient according to the correction light intensity of the correction light source under the conditions of clean air and gas to be detected; correcting the intensity of the detection light source under the condition of the gas to be detected by using the correction coefficient to obtain corrected intensity of the detection light; and determining the concentration of the target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air. The gas concentration detection method and the gas concentration detection system can solve the problem that the gas sensor is easily interfered by other substances in the air, and effectively improve the detection precision of the gas sensor.
Description
Technical Field
The invention relates to the technical field of gas concentration detection, in particular to a gas concentration detection method and system.
Background
With the development of industrial society, various gases are emitted in the air, and some of the gases may be harmful to human bodies, such as formaldehyde, TVOC (Total Volatile Organic Compounds ) released from various materials during house decoration, and harmful gases such as carbon monoxide, nitrogen oxides and the like in automobile exhaust. In order to ensure the living health of residents, various instruments are generally used for detecting air in daily life.
The existing air environment detection methods are various, such as an electrochemical detection method, a semiconductor gas sensor, a reagent colorimetry method, an infrared gas sensor and the like. The infrared gas sensor for detecting various harmful gases and the ultraviolet gas sensor researched and developed by the latest technology at present become the attention points of the future market by virtue of the advantages of high accuracy, high size integration level, high response speed, high reliability and the like. In daily use, when formaldehyde gas or VOC (Volatile Organic Compounds, volatile organic compound) gas is detected by ultraviolet rays, the ultraviolet rays emitted by the light source are attenuated to a certain extent due to the existence of some tiny particles and water vapor in the air, and whether the attenuation of the light rays is completely caused by the absorption of the formaldehyde gas or the VOC cannot be determined, so that errors are generated in the measurement result.
Disclosure of Invention
The invention aims to provide a gas concentration detection method and a gas concentration detection system, which can solve the problem that a gas sensor is easily interfered by other substances in the air and effectively improve the detection precision of the gas sensor.
In order to achieve the above object, the present invention provides the following solutions:
a gas concentration detection method comprising:
the light intensity of the light source under the conditions of clean air and gas to be detected is detected by utilizing the light detector; the light source is a correction light source or a detection light source; when the light source is a correction light source, the light intensity is the correction light intensity; when the light source is a detection light source, the light intensity is the detection light intensity;
determining a correction coefficient according to the correction light intensity of the correction light source under the conditions of clean air and gas to be detected;
correcting the intensity of the detection light source under the condition of the gas to be detected by using the correction coefficient to obtain corrected intensity of the detection light;
and determining the concentration of the target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air.
Optionally, the detecting the light intensity of the light source under the condition of clean air and gas to be detected by using the light detector specifically includes:
introducing pretreated clean air or gas to be detected which is not pretreated into the cavity of the gas sensor until the cavity is full of the gas; controlling the light source to emit light from one end of the cavity to the inside of the cavity; detecting the light intensity of the light source under the conditions of clean air and gas to be detected from the other end of the cavity through the light detector;
when the light source is a correction light source, the correction light source is a first ultraviolet LED light source, the light is correction light, and the correction light source corrects the light intensity under the condition of clean airThe correction light intensity of the correction light source in the presence of the gas to be measured>。
Optionally, the determining the correction coefficient according to the correction light intensity of the correction light source in the presence of clean air and the presence of the gas to be measured specifically includes:
according to the corrected light intensity of the corrected light source under the condition of clean air and gas to be detectedAnd->Adopts the formula->Determining correction factor->。
Optionally, the light intensity of the light source under the condition of clean air and gas to be detected is detected by the light detector, wherein when the light source is a detection light source, the detection light source is a second ultraviolet LED light source, the light is detection light, and the detection light intensity of the detection light source under the condition of clean airThe detection light intensity of the detection light source under the condition of the gas to be detected is +.>。
Optionally, the correcting the intensity of the detection light beam of the detection light source under the condition of the gas to be detected by using the correction coefficient to obtain the corrected intensity of the detection light beam specifically includes:
based on the formulaBy means of correction factors->The intensity of the detection light source in the presence of the gas to be detected +.>Correcting to obtain corrected detection light intensity +.>。
Optionally, the determining the concentration of the target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air specifically includes:
according to the corrected detected light intensityAnd detecting the intensity of the detected light of the light source in the presence of clean airAdopts the formula->Determining the concentration of the target gas->The method comprises the steps of carrying out a first treatment on the surface of the Wherein->Setting a coefficient for a first; the target gas is formaldehyde gas.
Optionally, the light source is detected by the light detector in the presence of clean air and the presence of gas to be detectedIn the light intensity under the condition of the body, the light source is a detection light source, the detection light source comprises a second ultraviolet LED light source and a third ultraviolet LED light source, the light is detection light, and the detection light intensity of the second ultraviolet LED light source under the condition of clean airThe third ultraviolet LED light source has detection light intensity in the presence of clean air>The method comprises the steps of carrying out a first treatment on the surface of the The detection light intensity of the second ultraviolet LED light source under the condition of the gas to be detected is +.>The third ultraviolet LED light source has detection light intensity +.>。
Optionally, the correcting the intensity of the detection light beam of the detection light source under the condition of the gas to be detected by using the correction coefficient to obtain the corrected intensity of the detection light beam specifically includes:
based on the formulaBy means of correction factors->The intensity of the detection light source in the presence of the gas to be detected +.>Correcting to obtain corrected detection light intensity +.>。
Based on the formulaBy means of correction factors->The detection light intensity of the third ultraviolet LED light source under the condition of the gas to be detected is +.>Correcting to obtain the third corrected detection light intensity +.>。
Optionally, the determining the concentration of the target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air specifically includes:
according to the detected light intensity after the second correctionAnd the second ultraviolet LED light source is in the detection light intensity of clean air condition +.>Adopts the formula->Determination of the concentration of formaldehyde gas->The method comprises the steps of carrying out a first treatment on the surface of the Wherein->Setting a coefficient for a first;
according to the concentration of formaldehyde gasAdopts the formula->Determination of the intensity variation caused by formaldehyde gasThe method comprises the steps of carrying out a first treatment on the surface of the Wherein->Setting a coefficient for a second;
according to the change of light intensity caused by formaldehyde gasAdopts the formula->Determining the concentration of VOC gas>The method comprises the steps of carrying out a first treatment on the surface of the Wherein 1 is a third setting coefficient.
A gas concentration detection system comprising:
the light intensity detection module is used for respectively detecting the light intensity of the correction light source and/or the detection light source under the conditions of clean air and gas to be detected by utilizing the light detector;
the correction module is used for determining a correction coefficient according to the correction light intensity of the correction light source under the conditions of clean air and gas to be detected; correcting the intensity of the detection light source under the condition of the gas to be detected by using the correction coefficient to obtain corrected intensity of the detection light;
and the gas concentration determining module is used for determining the concentration of the target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention provides a gas concentration detection method and a system, wherein a light detector is utilized to respectively detect the light intensity of a correction light source and a detection light source under the conditions of clean air and gas to be detected, so as to obtain a correction coefficient; obtaining the corrected detection light intensity by using the correction coefficient; and determining the concentration of the target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air. The gas concentration detection method and the gas concentration detection system can solve the problem that the gas sensor is easily interfered by other substances in the air, and effectively improve the detection precision of the gas sensor.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flowchart of a gas concentration detection method provided by the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a gas concentration detection method and a gas concentration detection system, which can solve the problem that a gas sensor is easily interfered by other substances in the air and effectively improve the detection precision of the gas sensor. Because the existing method for detecting the concentration of formaldehyde gas or VOC gas by utilizing ultraviolet rays has the defect of detection error caused by tiny particles, the invention mainly achieves the aim of enabling the concentration detection result to be more accurate by correcting the attenuation coefficient of the ultraviolet rays caused by the tiny particles and water vapor.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
Example 1
Fig. 1 is a flowchart of a gas concentration detection method provided by the present invention. As shown in fig. 1, the method for detecting gas concentration disclosed by the invention comprises the following steps:
and step 1, respectively detecting the light intensity of the light source under the conditions of clean air and gas to be detected by utilizing the light detector.
The light source is a correction light source or a detection light source; when the light source is a correction light source, the light intensity is the correction light intensity; when the light source is a detection light source, the light intensity is the detection light intensity.
In one embodiment, the step 1 specifically includes:
step 1.1.1, introducing pretreated clean air into the cavity until the cavity is full of the clean air; controlling the correction light source to emit correction light from one end of the cavity to the inside of the cavity; the correction light source is a first ultraviolet LED light source; detecting the other end of the cavity through the photodetector to obtain the corrected light intensity of the corrected light source under the condition of clean air. The first ultraviolet LED light source is an ultraviolet LED light source with the wavelength of 370 nm.
The pretreated clean air is free of tiny particles, water vapor or other gases capable of absorbing ultraviolet rays. When an ultraviolet LED light source is used as a detection light source, such as an ultraviolet LED light source with a wavelength of 315nm is used to detect formaldehyde gas, the ultraviolet LED light source with a wavelength of 315nm absorbs mainly formaldehyde gas, but when VOC gas such as toluene, xylene, ethylbenzene, etc. is present in the air, the ultraviolet LED light source with a wavelength of 315nm also absorbs a part of VOC gas, causing errors. In the same way, when the ultraviolet LED light source with the wavelength of 265nm is used for detecting VOC gas, a small part of the VOC gas is absorbed by formaldehyde gas, so that errors are caused. However, the formaldehyde gas or the VOC gas hardly absorbs the light emitted by the ultraviolet LED light source with the wavelength of 370nm (obtained according to the absorption spectrum of the formaldehyde gas and the VOC gas), so that the ultraviolet LED light source with the wavelength of 370nm is used as a correction light source, and the ultraviolet LED light source has stronger anti-interference capability.
Step 1.1.2, introducing the gas to be tested which is not pretreated into the cavity until the gas to be tested is filled in the cavity; controlling the correction light source to emit correction light from one end of the cavity to the inside of the cavity; from another of the cavities by means of a light detectorEnd detection to obtain the corrected light intensity of the corrected light source under the condition of the gas to be detected。
The gas to be detected which is not pretreated contains tiny particles, water vapor, target gas and the like.
In another embodiment, the step 1 specifically includes:
step 1.2.1, introducing pretreated clean air into the cavity until the cavity is full of the clean air; the detection light source is a second ultraviolet LED light source; controlling the detection light source to emit detection light from one end of the cavity to the inside of the cavity; detecting the intensity of the detection light source under the condition of clean air from the other end of the cavity through the light detector. And the second ultraviolet LED light source has the wavelength of 315nm.
Step 1.2.2, introducing the gas to be tested which is not pretreated into the cavity until the gas to be tested is filled in the cavity; controlling the detection light source to emit detection light from one end of the cavity to the inside of the cavity; detecting the light intensity of the detection light source under the condition of the gas to be detected from the other end of the cavity through the light detector。
And step 2, determining a correction coefficient according to the correction light intensity of the correction light source under the conditions of clean air and gas to be detected.
When the detection light source of the gas sensor is an ultraviolet LED light source, since the correction light source adopted in the present embodiment is also an ultraviolet LED light source and the optical path is shorter in the corresponding detection structure, the ultraviolet attenuation ratio of particulate matters and the like in the air set in the detection structure of the gas sensor to the detection light source and the correction light source is the same and defined as the correction coefficient.
In particular, the detection of the light detector in the presence of clean air and in the presence of a gas to be measured is based on a correction light sourceThe resulting corrected light intensityAnd->Adopts the formula->Determining correction factor->. The correction coefficient->The correction coefficient of the detection light source for particulate matters, water vapor and the like except for target gases such as formaldehyde gas, VOC gas and the like in the gas to be detected.
And 3, correcting the detection light intensity of the detection light source under the condition of the gas to be detected by using the correction coefficient to obtain corrected detection light intensity.
Specifically, based on the formulaBy means of correction factors->The intensity of the detection light source in the presence of the gas to be detected +.>Correcting to obtain corrected detection light intensity +.>。
And 4, determining the concentration of the target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air.
Specifically, according to the corrected detected light intensityAnd the intensity of the detection light source in the presence of clean air +.>The concentration of the target gas is determined by the following formula (1)>。
（1）
Wherein the method comprises the steps ofFor the first set coefficient and->The method comprises the steps of carrying out a first treatment on the surface of the The target gas in this example 1 is formaldehyde gas.
For the first set coefficientAccording to beer's law>Wherein->Is the intensity of the ultraviolet radiation at the light source; />The intensity of ultraviolet radiation at the detection end; />The ultraviolet absorption function of different gases to different wavelengths under the conditions of different distances and different concentrations; />The ultraviolet absorption function of different gases to be detected on different wave bands is adopted;lthe optical path is the distance from the light source to the detection end, and the unit is cm; />For the concentration of the gas to be detected, the unit isppm（10 -6 ）。
Because the formaldehyde gas target concentration in the gas to be detected is low, and the optical path is arranged in the detection structure of the gas sensorShorter, thus->The value of (2) is very low. Based on the mathematical general knowledge, when +.>When the value of (2) is very low, even close to 0, < >>Obtain->From this +.>。
That is to say,
。
in the wavelength of315nm (Japan)>Ultraviolet absorbance of formaldehyde gas at 315nm, optical path in this examplel=15cm。
Example 2
Example 2 is different from example 1 in that a detection light source is used, and the source is different from the target gas to be detected, example 1 is used only for detecting the concentration of formaldehyde gas, and example 2 can be used for detecting the concentrations of formaldehyde gas and VOC gas.
As shown in fig. 1, the method for detecting gas concentration disclosed by the invention comprises the following steps:
and step 1, respectively detecting the light intensity of the light source under the conditions of clean air and gas to be detected by utilizing the light detector.
The clean air or the gas to be measured is arranged in a cavity of the gas sensor, the correction light source is arranged at one end of the cavity, and the light detector is arranged at the other end of the cavity.
In one embodiment, the step 1 specifically includes:
step 1.1.1, introducing pretreated clean air into the cavity until the cavity is full of the clean air; controlling the correction light source to emit correction light from one end of the cavity to the inside of the cavity; the correction light source is a first ultraviolet LED light source; detecting the other end of the cavity through the photodetector to obtain the corrected light intensity of the corrected light source under the condition of clean air。
Step 1.1.2, introducing the gas to be tested which is not pretreated into the cavity until the gas to be tested is filled in the cavity; controlling the correction light source to emit correction light from one end of the cavity to the inside of the cavity; detecting the other end of the cavity through the photodetector to obtain the corrected light intensity of the corrected light source under the condition of the gas to be detected。
The gas to be detected which is not pretreated contains tiny particles, water vapor, formaldehyde gas, VOC gas (such as toluene and xylene) and the like.
In another embodiment, the step 1 specifically includes:
step 1.2.1, introducing pretreated clean air into the cavity until the cavity is full of the clean air; controlling the detection light source to emit detection light from one end of the cavity to the inside of the cavity; the detection light source comprises a second ultraviolet LED light source and a third ultraviolet LED light source; detection from the other end of the cavity by means of a photodetectorObtaining the detected light intensity of the second ultraviolet LED light source under the condition of clean airAnd the third ultraviolet LED light source is in the presence of clean air detection light intensity +.>. The third ultraviolet LED light source is an ultraviolet LED light source with the wavelength of 256 nm.
Step 1.2.2, introducing the gas to be tested which is not pretreated into the cavity until the gas to be tested is filled in the cavity; controlling the detection light source to emit detection light from one end of the cavity to the inside of the cavity; detecting the detected light intensity of the second ultraviolet LED light source under the condition of the gas to be detected from the other end of the cavity through the light detectorAnd the detection light intensity of the third ultraviolet LED light source under the condition of the gas to be detected +.>。
And step 2, determining a correction coefficient according to the correction light intensity of the correction light source under the conditions of clean air and gas to be detected.
Specifically, according to the corrected light intensity of the corrected light source in the presence of clean air and the gas to be measuredAnd->Adopts the formula->Determining correction factor->。
And 3, respectively detecting the detection light intensity of the detection light source under the conditions of clean air and gas to be detected by using the light detector.
And 3, correcting the detection light intensity of the detection light source under the condition of the gas to be detected by using the correction coefficient to obtain corrected detection light intensity.
Specifically, based on the formulaBy means of correction factors->The detection light intensity of an ultraviolet LED light source with the wavelength of 315nm under the condition of the gas to be detected is +.>Performing correction to obtain the first corrected detection light intensity +.>。
Based on the formulaBy means of correction factors->The detection light intensity of an ultraviolet LED light source with the wavelength of 265nm under the condition of the gas to be detected is +.>Correcting to obtain the second corrected detection light intensity +.>。
And 4, determining the concentration of the target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air.
Since toluene has very low absorption and almost no absorption of ultraviolet light emitted from an ultraviolet LED light source with a wavelength of 315nm, the intensity of the detection light after the first correction in this example 2And the detection light intensity of an ultraviolet LED light source with a wavelength of 315nm in the presence of clean air +.>Determining the concentration of formaldehyde gas in the gas to be measured by the following formula (2)>。
（2）
According to the concentration of formaldehyde gasThe detection light intensity emitted from the 265nm ultraviolet LED light source is calculated by the following formula (3)>To->Light intensity variation caused by formaldehyde gas +.>。
（3）
Wherein the method comprises the steps ofFor a second set coefficient and->Wavelength->265nm (mm)>In this case, the absorbance of formaldehyde gas at 265nm is ultravioletOptical path length in example 2l=15cm。
According to the change of light intensity caused by formaldehyde gasThe concentration of VOC gas is determined by the following formula (4)>。
（4）
That is to say,
（5）
wherein the method comprises the steps ofFor a third set coefficient and->Wavelength->265nm (mm)>Ultraviolet absorbance of VOC gas at 265nm, optical path in this example 2l=15cm。
In addition, since some photodetectors can detect ultraviolet light in different wavelength bands (such as 265nm, 315nm, 370nm wavelength bands) simultaneously, in embodiment 1 and embodiment 2, step 1.1.1 and step 1.2.1 can be performed simultaneously.
For the detection light source and the correction light source in example 1 and example 2, the detection was performed when the pretreated clean air was irradiated with the light、/>And->The corresponding light source can be determined in a laboratory ideal environment +.>、/>And->And is inputted in advance into a program to calculate a correction coefficient, so that some steps can be omitted. The method steps mentioned in the embodiment of the invention take into consideration that the light power of the ultraviolet LED light source is attenuated to a certain extent after long-time use, and the sensitivity of the optical detector is affected to some extent, so that in order to ensure the most accurate test result, the method adopts the method that the pretreatment clean air is introduced each time, and the detection is carried out to obtain ++>、/>And->Is a value of (2).
In the gas concentration detection method provided by the invention, the characteristic that an ultraviolet LED light source with the wavelength of 370nm is hardly absorbed by formaldehyde gas and VOC gas is utilized to determine the correction coefficient, and the detection result of the formaldehyde gas by the ultraviolet LED light source with the wavelength of 315nm is corrected by the correction coefficient; in addition, after the correction coefficient is determined by the ultraviolet LED light source with the wavelength of 370nm, the detection result of VOC gas by the ultraviolet LED light source with the wavelength of 265nm is corrected by the correction coefficient, and meanwhile, the influence of formaldehyde gas on the ultraviolet LED light source with the wavelength of 265nm is eliminated by the ultraviolet LED light source with the wavelength of 370 nm. In the embodiment 1 and the embodiment 2 of the present invention, the ultraviolet gas sensor is adopted, and in addition, in other embodiments, an infrared gas sensor may be adopted, and a gas concentration detection method using the infrared gas sensor is similar to a detection method using the ultraviolet gas sensor.
In summary, compared with the existing gas concentration detection technology, the method has at least the following advantages:
1) The gas concentration detection method provided by the invention eliminates the influence of tiny particles, water vapor and the like in the air on the detection result when the light detector detects formaldehyde gas and VOC gas, and effectively improves the detection precision of the gas concentration.
2) The gas concentration detection method provided by the invention eliminates the influence of formaldehyde gas possibly existing on the detection result when VOC gas is detected, and further improves the detection precision of the gas concentration.
Based on the gas concentration detection method provided by the invention, the invention also provides a gas concentration detection system, which comprises the following steps:
the light intensity detection module is used for respectively detecting the light intensity of the correction light source and/or the detection light source under the conditions of clean air and gas to be detected by utilizing the light detector;
the correction module is used for determining a correction coefficient according to the correction light intensity of the correction light source under the conditions of clean air and gas to be detected; correcting the intensity of the detection light source under the condition of the gas to be detected by using the correction coefficient to obtain corrected intensity of the detection light;
and the gas concentration determining module is used for determining the concentration of the target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (5)
1. A gas concentration detection method, characterized by comprising:
the light intensity of the light source under the conditions of clean air and gas to be detected is detected by utilizing the light detector; the light source is a correction light source or a detection light source; when the light source is a correction light source, the light intensity is the correction light intensity; when the light source is a detection light source, the light intensity is the detection light intensity;
determining a correction coefficient according to the correction light intensity of the correction light source under the conditions of clean air and gas to be detected;
correcting the intensity of the detection light source under the condition of the gas to be detected by using the correction coefficient to obtain corrected intensity of the detection light;
determining the concentration of target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air;
the light intensity of the light source under the conditions of clean air and gas to be detected is detected by the light detector respectively, and the method specifically comprises the following steps:
introducing pretreated clean air or gas to be detected which is not pretreated into the cavity of the gas sensor until the cavity is full of the gas; controlling the light source to emit light from one end of the cavity to the inside of the cavity; detecting the light intensity of the light source under the conditions of clean air and gas to be detected from the other end of the cavity through the light detector;
when the light source is a correction light source, the correction light source is a first ultraviolet LED light source, the light is correction light, and the correction light source corrects the light intensity under the condition of clean airThe correction light intensity of the correction light source in the presence of the gas to be measured>；
The method for determining the correction coefficient according to the correction light intensity of the correction light source under the conditions of clean air and gas to be detected specifically comprises the following steps:
according to the corrected light intensity of the corrected light source under the condition of clean air and gas to be detectedAnd->Using the formulaDetermining correction factor->；
The light source is a detection light source, the detection light source comprises a second ultraviolet LED light source and a third ultraviolet LED light source, the light is detection light, and the intensity of the detection light of the second ultraviolet LED light source under the condition of clean air is that of the detection light of the light source under the condition of clean airThe third ultraviolet LED light source has detection light intensity in the presence of clean air>The method comprises the steps of carrying out a first treatment on the surface of the The detection light intensity of the second ultraviolet LED light source under the condition of the gas to be detected is +.>The third VioletThe detection light intensity of the external LED light source in the presence of the gas to be detected +.>；
The method for correcting the intensity of the detection light rays of the detection light source under the condition of the gas to be detected by using the correction coefficient to obtain the corrected intensity of the detection light rays specifically comprises the following steps:
based on the formulaBy means of correction factors->The detection light intensity of the second ultraviolet LED light source under the condition of the gas to be detected is +.>Correcting to obtain the second corrected detection light intensity +.>；
Based on the formulaBy means of correction factors->The detection light intensity of the third ultraviolet LED light source under the condition of the gas to be detected is +.>Correcting to obtain the third corrected detection light intensity +.>；
The method for determining the concentration of the target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air specifically comprises the following steps:
according to the detected light intensity after the second correctionAnd the second ultraviolet LED light source is in the detection light intensity of clean air condition +.>Adopts the formula->Determination of the concentration of formaldehyde gas->The method comprises the steps of carrying out a first treatment on the surface of the Wherein->For the first set coefficient, +.>Wherein->For the first wavelength, +.>For formaldehyde gas>Ultraviolet absorbance at the time, optical path is l;
according to the concentration of formaldehyde gasAdopts the formula->Determination of the intensity variation caused by formaldehyde gasThe method comprises the steps of carrying out a first treatment on the surface of the Wherein->For the second set coefficient, +.>Wherein->For the second wavelength, +.>The ultraviolet absorbance of formaldehyde gas at the time of the reaction is shown, and the optical path is l;
according to the change of light intensity caused by formaldehyde gasAdopts the formula->Determining the concentration of the VOC gas; wherein->And a third setting coefficient is set, wherein I5 is the detection light intensity of the third ultraviolet LED light source under the condition of clean air.
2. The method of claim 1, wherein the first wavelength315nm.
3. The method of claim 1, wherein the second wavelength265nm.
4. The method according to claim 1, wherein the optical path l is 15cm.
5. A gas concentration detection method according to claim 1, wherein a gas concentration detection system corresponding to the gas concentration detection method comprises:
the light intensity detection module is used for respectively detecting the light intensity of the correction light source and/or the detection light source under the conditions of clean air and gas to be detected by utilizing the light detector;
the correction module is used for determining a correction coefficient according to the correction light intensity of the correction light source under the conditions of clean air and gas to be detected; correcting the intensity of the detection light source under the condition of the gas to be detected by using the correction coefficient to obtain corrected intensity of the detection light;
and the gas concentration determining module is used for determining the concentration of the target gas in the gas to be detected according to the corrected detection light intensity and the detection light intensity of the detection light source under the condition of clean air.
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