CN113075154A - Non-dispersive infrared gas concentration detection device and detection method based on platinum resistor - Google Patents
Non-dispersive infrared gas concentration detection device and detection method based on platinum resistor Download PDFInfo
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 title claims abstract description 227
- 229910052697 platinum Inorganic materials 0.000 title claims abstract description 114
- 238000001514 detection method Methods 0.000 title claims abstract description 76
- 230000003321 amplification Effects 0.000 claims abstract description 23
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 23
- 230000003287 optical effect Effects 0.000 claims abstract description 23
- 230000001360 synchronised effect Effects 0.000 claims abstract description 14
- 239000007789 gas Substances 0.000 claims description 61
- 230000008859 change Effects 0.000 claims description 15
- 238000010521 absorption reaction Methods 0.000 claims description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
- 239000003990 capacitor Substances 0.000 claims description 6
- 238000012545 processing Methods 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 5
- 238000004458 analytical method Methods 0.000 claims description 4
- 238000012937 correction Methods 0.000 claims description 4
- 230000009471 action Effects 0.000 claims description 3
- 239000013078 crystal Substances 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 238000002955 isolation Methods 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 229910052594 sapphire Inorganic materials 0.000 claims description 3
- 239000010980 sapphire Substances 0.000 claims description 3
- 230000009466 transformation Effects 0.000 claims description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 2
- 239000010931 gold Substances 0.000 claims description 2
- 229910052737 gold Inorganic materials 0.000 claims description 2
- 230000005236 sound signal Effects 0.000 claims description 2
- 230000002708 enhancing effect Effects 0.000 claims 1
- 238000004868 gas analysis Methods 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 16
- 238000005259 measurement Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 4
- 239000000523 sample Substances 0.000 description 4
- 238000000862 absorption spectrum Methods 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000000295 emission spectrum Methods 0.000 description 1
- 230000005281 excited state Effects 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000005283 ground state Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 150000003057 platinum Chemical class 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
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- 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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- 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
- G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration
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Abstract
The invention relates to a non-dispersive infrared gas concentration detection device and a non-dispersive infrared gas concentration detection method based on a platinum resistor, and relates to the technical field of gas analysis. The device comprises a light source emitter, an optical flow cell, a filter, a platinum resistance detection unit, an instrument amplification circuit, a frequency-selective amplifier and a synchronous acquisition module; light emitted by the light source emitter sequentially penetrates through the light flow cell, the filter plate and the platinum resistor detection unit, detection signals are amplified through the instrument amplification circuit and then amplified through the frequency-selective amplifier, and finally amplified data are transmitted to the synchronous acquisition module. The invention effectively solves the problems of complex operation, low real-time performance, high manufacturing cost, poor anti-interference performance, insufficient precision and the like of the traditional non-dispersive infrared gas detection system, and has simple operation, convenience and practicability.
Description
Technical Field
The invention relates to a non-dispersive infrared gas concentration detection device and a non-dispersive infrared gas concentration detection method based on a platinum resistor, and relates to the technical field of gas analysis.
Background
With the development of industry and agriculture, gas detection is a very important work, a plurality of industries have no more work, and the timely and accurate monitoring, prediction and control of flammable, explosive, toxic and harmful gases become problems to be solved urgently in the industries such as coal, petroleum, chemical industry, electric power and the like.
According to the analytical instrument which works according to the characteristic that different component gases have selective absorption to infrared rays with different wavelengths, the emission spectrum of a light source only absorbs at the part which is overlapped with the absorption spectrum of the gas, the light intensity after absorption changes, the type of the gas can be distinguished by measuring the absorption spectrum, and the concentration of the gas to be measured can be determined by measuring the absorption intensity. When infrared radiation of a particular wavelength is absorbed by the gas and a particular vibrational or rotational motion is produced thereby causing a net change in dipole moment, the resulting gas vibration and rotational energy excites a transition from the ground state to the excited state, causing a reduction in the transmitted luminosity corresponding to this region. Therefore, specific molecules selectively absorb infrared light, the infrared gas analysis method is based on that gas absorbs infrared light with specific wavelength, and the absorption meets the Lambert-Beer law that I is I0exp(-kλcl)。
The infrared gas detection and analysis has wide application range, can analyze gas components and solution components, has higher sensitivity and quick response, can continuously indicate on line, and can form an adjusting system. The detection part of the infrared gas analyzer commonly used in the industry at present consists of two parallel optical signal cells with the same structure: one is a measurement chamber and one is a reference chamber. The two chambers are simultaneously or alternately opened and closed by a light cutting plate in a certain period. The common method is relatively complex in structure and easy to generate cross interference; secondly, signals of the two photoacoustic cells cannot be synchronously acquired in real time, and under the condition, the reference adjustment of light intensity has time errors; some of the devices still use mechanical modulation light sources, and have the disadvantages of large volume, complex operation and high cost; finally, various external influences, such as external light, vibration, air chamber pollution, etc., cannot be effectively avoided.
CN108489924A discloses a sensing probe and a non-dispersive infrared gas sensor detection system, wherein the sensing probe comprises an infrared light source, an optical air chamber, an infrared sheet array and an infrared detector array; the optical air chamber is respectively provided with an air inlet hole and an air outlet hole which are communicated with the gas environment to be measured; the infrared light source is arranged at the head end of the optical air chamber; the infrared light sheet array and the infrared detector array are sequentially arranged at the tail part of the optical air chamber; the infrared sheet array comprises a plurality of detection filters and a contrast filter; the infrared detector array comprises a plurality of infrared detectors which are respectively in one-to-one correspondence with the detection optical filters and the contrast optical filters; after the infrared light source emits wide-spectrum infrared light, the infrared light sequentially passes through the optical air chamber and the infrared light sheet array and then is emitted to enter the infrared detector array. The application can measure the concentration of various gases simultaneously by utilizing an infrared sheet array and an infrared detector array. However, the above patent application also has the problems of complex operation, low real-time performance and high cost, and particularly has the problems of not ideal anti-interference performance and not high detection precision.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a platinum resistor-based non-dispersive infrared gas concentration detection device and a platinum resistor-based non-dispersive infrared gas concentration detection method, which are used for solving the problems of complex operation, low instantaneity, high manufacturing cost, poor anti-interference performance, insufficient precision and the like of the traditional non-dispersive infrared gas detection system, and are simple to operate, convenient and practical.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a non-dispersive infrared gas concentration detection device based on a platinum resistor comprises a light source emitter, an optical flow cell, a filter, a platinum resistor detection unit, an instrument amplification circuit, a frequency-selective amplifier and a synchronous acquisition module; the light emitted by the light source emitter sequentially penetrates through the light flow cell, the filter plate and the platinum resistor detection unit, a detection signal is amplified through the instrument amplification circuit and then is amplified through the frequency-selective amplifier, and finally, the amplified data are transmitted to the synchronous acquisition module; an air inlet valve and an air outlet valve are arranged on the optical flow cell;
the instrument amplifying circuit comprises a filter resistor R1, a filter resistor R7, a filter resistor R8, a filter resistor R9, a filter resistor R10, an operational amplifier U4, a basic proportion amplifying branch, a first basic frequency-selecting operational amplifier branch and a second basic frequency-selecting operational amplifier branch; the basic proportion amplification branch circuit is formed by connecting a filter resistor R2, a filter resistor R3, a capacitor C1 and an operational amplifier U1 in parallel; the first basic frequency-selecting operational amplifier branch is formed by connecting a capacitor C2 and an operational amplifier U2 in parallel, and is connected with a filter resistor R4 in series; the second basic frequency-selecting operational amplifier branch is formed by connecting a filter resistor R6 and an operational amplifier U3 in parallel and is connected with a filter resistor R5 in series; the first basic frequency-selecting operational amplifier branch and the second basic frequency-selecting operational amplifier branch are used for realizing frequency-selecting isolation of signals;
the basic proportional amplification branch is connected with a filter resistor R1 and a filter resistor R8 in series, the first basic frequency-selecting operational amplifier branch and the second basic frequency-selecting operational amplifier branch are connected with a filter resistor R7 in series, two circuits connected in series are connected with the filter resistor R9 in parallel, and then the two circuits are connected with a parallel circuit consisting of the filter resistor R10 and an operational amplifier U4 in series.
Furthermore, the central wavelength of the filter is the wavelength of the absorption wave peak of the gas to be measured, and the filter is used for filtering light with non-wave peak wavelength.
Further, the platinum resistance detection unit is powered through an ADR425 standard signal source.
Further, the optical flow cell is used for storing gas to be detected, and during detection, the air inlet valve and the air outlet valve are kept in a normally closed state.
Further, the light source emitter is an electrically modulated light source emitter.
Furthermore, the light source emitter emits a light source which is an electrically modulated square wave infrared light source, and the electrically modulated square wave infrared light source utilizes the frequency division of the MCU to obtain a frequency band which is completely the same as that of the synchronous acquisition module during data processing.
Further, the platinum resistance detection unit comprises a sapphire crystal and 4 pt1000 platinum resistances which are respectively a first pt1000 platinum resistance, a second pt1000 platinum resistance, a third pt1000 platinum resistance and a fourth pt1000 platinum resistance, and the 4 pt1000 platinum resistances are arranged in a wheatstone bridge manner.
Further, in the platinum resistance detection unit, a first pt1000 platinum resistance and a second pt1000 platinum resistance are used for physical shading; the third pt1000 platinum resistor and the fourth pt1000 platinum resistor are used for light passing, and the change of the resistance value of the Wheatstone bridge platinum resistor reflects the change of the concentration of the detected gas.
Further, the inner wall of the light flow cell is plated with a gold film to enhance the reflection of the sound signal.
The detection method of the non-dispersive infrared gas concentration detection device based on the platinum resistor comprises the following steps:
s1: opening an upper air inlet valve of the optical flow cell, closing an air outlet valve, introducing nitrogen into the optical flow cell for 10s, opening the air outlet valve, and repeating the action for more than 3 times to clean the optical flow cell; opening an air inlet valve, closing an air outlet valve, and introducing the gas to be detected for 10s for sample introduction;
s2: the light source emitter emits infrared light, and light with the central wavelength of the gas not to be measured is filtered through the filter plate;
s3: after receiving the irradiation of specific light intensity, a third pt1000 platinum resistor and a fourth pt1000 platinum resistor in the platinum resistor detection unit generate heat change, so that resistance values change, the first pt1000 platinum resistor and the second pt1000 platinum resistor perform physical shading and do not generate resistance value change, and light detection signals are generated through resistance value differences between two groups of platinum resistors of the first pt1000 platinum resistor, the second pt1000 platinum resistor, the third pt1000 platinum resistor and the fourth pt1000 platinum resistor;
s4: the signal difference value X of the Wheatstone bridge type platinum resistor in the platinum resistor detection unit is amplified through an instrument amplification circuit and then amplified through a frequency-selective amplifier;
s5: the synchronous acquisition module synchronously collects the amplified difference detection signals, and performs light intensity correction, data reference analysis and digital phase-locked frequency selection processing;
s6: calculating the concentration of the gas to be measured through linear transformation, wherein a signal difference value X after the Wheatstone bridge type platinum resistor is enhanced is obtained through the step S5, and the signal difference value X and the concentration Y of the gas to be measured satisfy a linear relation: y ═ dX + e where d, e are constants.
Compared with the prior art, the invention has the following technical effects:
the invention provides a platinum resistor-based non-dispersive infrared gas concentration detection device and a platinum resistor-based non-dispersive infrared gas concentration detection method, which solve the problems of complex structure, inconvenient operation, low instantaneity, high manufacturing cost, poor anti-interference performance, error in light intensity reference, insufficient precision and the like of the traditional non-dispersive infrared gas detection system. The device and the method have the advantages of simple structure, high gain effect, strong detection sensitivity, simple operation, convenience and practicability.
Drawings
FIG. 1 is a schematic diagram of a platinum resistor-based non-dispersive infrared gas concentration detection device according to the present invention;
FIG. 2 is a schematic diagram of the structure of a platinum resistance detecting unit according to the present invention;
FIG. 3 is a schematic diagram of the instrument amplification circuit of the present invention;
FIG. 4 is a waveform of a concentration measurement experiment signal of a reference nitrogen gas when a methane absorption wavelength filter is selected according to the present invention;
FIG. 5 is a waveform of experimental signal for concentration measurement of 1ppm methane in the present invention when a methane absorption wavelength filter is selected;
FIG. 6 is a waveform diagram of experimental signals for concentration measurement of 2ppm methane in the present invention when a methane absorption wavelength filter is selected.
Detailed Description
The invention will be described in further detail below with reference to the accompanying figures 1-6 and specific examples.
Example 1
As shown in fig. 1 and 2, the non-dispersive infrared gas concentration detection device based on platinum resistor of the present embodiment includes a light source emitter 1, a light flux cell 2, a filter 3, a platinum resistor detection unit 4, an instrument amplification circuit 5, a frequency selective amplifier 6, and a synchronous acquisition module 7. Light rays emitted by the light source emitter 1 sequentially penetrate through the light flow cell 2, the filter plate 3 and the platinum resistor detection unit 4, detection signals are amplified through the instrument amplification circuit 5 and then amplified through the frequency-selective amplifier 6, and finally amplified data are transmitted to the synchronous acquisition module 7. The light flow cell 2 is provided with an air inlet valve 8 and an air outlet valve 9.
The light source emitted by the light source emitter 1 is an electrically modulated square wave infrared light source, and the electrically modulated square wave infrared light source utilizes the frequency division of the MCU to obtain a frequency band completely the same as that of the synchronous acquisition module 7 during data processing. The central wavelength of the filter 3 is the wavelength of the absorption wave peak of the gas to be measured, and the filter 3 is used for filtering light with non-wave peak wavelength. The platinum resistance detection unit 4 is powered by an ADR425 standard signal source 10. The optical flow cell 2 is used for storing gas to be detected, and during detection, the air inlet valve 8 and the air outlet valve 9 are kept in a normally closed state. The platinum resistance detection unit 4 comprises a sapphire crystal 4-1 and 4 pt1000 platinum resistances, namely a first pt1000 platinum resistance 4-2, a second pt1000 platinum resistance 4-3, a third pt1000 platinum resistance 4-4 and a fourth pt1000 platinum resistance 4-5, wherein the 4 pt1000 platinum resistances are arranged in a Wheatstone bridge manner. The first pt1000 platinum resistor 4-2 and the second pt1000 platinum resistor 4-3 are used for physical shading. The third pt1000 platinum resistor 4-4 and the fourth pt1000 platinum resistor 4-5 are used for light passing, and the change of the resistance value of the Wheatstone bridge platinum resistor reflects the change of the concentration of the detected gas. The magnitude of the resistance value change signal of the platinum resistor is in direct proportion to the absorbed light intensity, and the signal is subjected to proportional processing through a series of proportional amplification and correction, so that the voltage signal transmitted to the last is in linear relation with the absorbed light intensity.
As shown in fig. 3, the instrument amplification circuit 5 includes a filter resistor R1, a filter resistor R7, a filter resistor R8, a filter resistor R9, a filter resistor R10, an operational amplifier U4, a basic proportional amplification branch, a first basic frequency-selective operational amplifier branch, and a second basic frequency-selective operational amplifier branch. The basic proportion amplification branch is formed by connecting a filter resistor R2, a filter resistor R3, a capacitor C1 and an operational amplifier U1 in parallel. The first basic frequency-selecting operational amplifier branch is formed by connecting a capacitor C2 and an operational amplifier U2 in parallel, and is connected with a filter resistor R4 in series. The second basic frequency-selecting operational amplifier branch is formed by connecting a filter resistor R6 and an operational amplifier U3 in parallel and is connected with a filter resistor R5 in series. The first basic frequency-selecting operational amplifier branch and the second basic frequency-selecting operational amplifier branch are used for realizing frequency-selecting isolation of signals.
The basic proportional amplification branch is connected with a filter resistor R1 and a filter resistor R8 in series, the first basic frequency-selecting operational amplifier branch and the second basic frequency-selecting operational amplifier branch are connected with a filter resistor R7 in series, two circuits connected in series are connected with the filter resistor R9 in parallel, and then the two circuits are connected with a parallel circuit consisting of the filter resistor R10 and an operational amplifier U4 in series.
The detection method of the non-dispersive infrared gas concentration detection device based on the platinum resistor comprises the following steps:
s1: and opening an upper air inlet valve 8 of the optical flow cell 2, closing an air outlet valve 9, introducing nitrogen gas into the optical flow cell 2 for 10s, opening the air outlet valve 9, and repeating the action for more than 3 times to clean the optical flow cell 2. And opening the air inlet valve 8, closing the air outlet valve 9, and introducing the gas to be detected for 10 seconds for sample injection.
S2: the light source emitter 1 emits infrared light, and light with a central wavelength of gas to be measured is filtered by the filter 3.
S3: a third pt1000 platinum resistor 4-4 and a fourth pt1000 platinum resistor 4-5 in the platinum resistor detection unit 4 generate heat change after receiving irradiation of specific light intensity, so that resistance values are changed, the first pt1000 platinum resistor 4-2 and the second pt1000 platinum resistor 4-3 perform physical shading without resistance value change, and light detection signals are generated through resistance value differences between two groups of platinum resistors, namely the first pt1000 platinum resistor 4-2, the second pt1000 platinum resistor 4-3, the third pt1000 platinum resistor 4-4 and the fourth pt1000 platinum resistor 4-5.
S4: the signal difference value X of the Wheatstone bridge type platinum resistor in the platinum resistor detection unit 4 is amplified through an instrument amplification circuit 5 and then amplified through a frequency-selective amplifier 6.
S5: the synchronous acquisition module 7 synchronously collects the amplified difference detection signals, and performs light intensity correction, data reference analysis and digital phase-locked frequency selection processing.
S6: calculating the concentration of the gas to be measured through linear transformation, wherein a signal difference value X after the Wheatstone bridge type platinum resistor is enhanced is obtained through the step S5, and the signal difference value X and the concentration Y of the gas to be measured satisfy a linear relation: y ═ dX + e, where d and e are constants, in this example, d ═ 10, and e ═ 84.
As shown in fig. 4-6, three waveforms are waveforms of an experiment performed on concentration measurement of reference nitrogen, methane 1 and methane 2 when a methane filter is selected in the measurement system of the present invention, the cell to be measured needs to be cleaned by constant inflation for 3 times before measurement, and the measurement results after conversion are shown in the following table, so that the detection accuracy and the anti-interference performance are greatly improved.
TABLE 1 measurement of three gases
The above is only a preferred embodiment of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.
Claims (10)
1. A non-dispersive infrared gas concentration detection device based on a platinum resistor comprises a light source emitter (1), an optical flow cell (2), a filter (3), a platinum resistor detection unit (4), an instrument amplification circuit (5), a frequency-selective amplifier (6) and a synchronous acquisition module (7); light rays emitted by the light source emitter (1) sequentially penetrate through the light flow cell (2), the filter (3) and the platinum resistor detection unit (4), detection signals are amplified through the instrument amplification circuit (5) and then amplified through the frequency selection amplifier (6), and finally amplified data are transmitted to the synchronous acquisition module (7); be equipped with admission valve (8) and air outlet valve (9) on light flow cell (2), its characterized in that:
the instrument amplification circuit (5) comprises a filter resistor R1, a filter resistor R7, a filter resistor R8, a filter resistor R9, a filter resistor R10, an operational amplifier U4, a basic proportion amplification branch, a first basic frequency-selective operational amplifier branch and a second basic frequency-selective operational amplifier branch; the basic proportion amplification branch circuit is formed by connecting a filter resistor R2, a filter resistor R3, a capacitor C1 and an operational amplifier U1 in parallel; the first basic frequency-selecting operational amplifier branch is formed by connecting a capacitor C2 and an operational amplifier U2 in parallel, and is connected with a filter resistor R4 in series; the second basic frequency-selecting operational amplifier branch is formed by connecting a filter resistor R6 and an operational amplifier U3 in parallel and is connected with a filter resistor R5 in series; the first basic frequency-selecting operational amplifier branch and the second basic frequency-selecting operational amplifier branch are used for realizing frequency-selecting isolation of signals;
the basic proportional amplification branch is connected with a filter resistor R1 and a filter resistor R8 in series, the first basic frequency-selecting operational amplifier branch and the second basic frequency-selecting operational amplifier branch are connected with a filter resistor R7 in series, two circuits connected in series are connected with the filter resistor R9 in parallel, and then the two circuits are connected with a parallel circuit consisting of the filter resistor R10 and an operational amplifier U4 in series.
2. The platinum resistor-based non-dispersive infrared gas concentration detection device according to claim 1, wherein: the central wavelength of the filter (3) is the wavelength of the absorption wave peak of the gas to be measured, and the filter (3) is used for filtering light with non-wave peak wavelength.
3. The platinum resistor-based non-dispersive infrared gas concentration detection device according to claim 1, wherein: the platinum resistance detection unit (4) is powered by an ADR425 standard signal source (10).
4. The platinum resistor-based non-dispersive infrared gas concentration detection device according to claim 1, wherein: the light flow cell (2) is used for storing gas to be detected, and during detection, the air inlet valve (8) and the air outlet valve (9) are kept in a normally closed state.
5. The platinum resistor-based non-dispersive infrared gas concentration detection device according to claim 1, wherein: the light source emitter (1) is an electrically modulated light source emitter.
6. The platinum resistor-based non-dispersive infrared gas concentration detection device according to claim 5, wherein: the light source emitter (1) emits light source which is an electric modulation square wave infrared light source, and the electric modulation square wave infrared light source utilizes the frequency division of the MCU to obtain the frequency band which is completely the same as the frequency band when the synchronous acquisition module (7) processes data.
7. The platinum resistor-based non-dispersive infrared gas concentration detection device according to claim 1, wherein: the platinum resistance detection unit (4) comprises a sapphire crystal (4-1) and 4 pt1000 platinum resistances which are respectively a first pt1000 platinum resistance (4-2), a second pt1000 platinum resistance (4-3), a third pt1000 platinum resistance (4-4) and a fourth pt1000 platinum resistance (4-5), and the 4 pt1000 platinum resistances are arranged in a Wheatstone bridge mode.
8. The platinum resistor-based non-dispersive infrared gas concentration detection device according to claim 7, wherein: in the platinum resistance detection unit (4), a first pt1000 platinum resistance (4-2) and a second pt1000 platinum resistance (4-3) are used for carrying out physical shading; the third pt1000 platinum resistor (4-4) and the fourth pt1000 platinum resistor (4-5) are used for light passing, and the change of the resistance value of the Wheatstone bridge platinum resistor reflects the change of the concentration of the detected gas.
9. The platinum resistor-based non-dispersive infrared gas concentration detection device according to claim 1, wherein: the inner wall of the light flow cell (2) is plated with a gold film for enhancing the reflection of sound signals.
10. A method for detecting a platinum resistor-based non-dispersive infrared gas concentration detection device according to any one of claims 1 to 9, characterized by comprising the following steps:
s1: opening an upper air inlet valve (8) of the optical flow cell (2), closing an air outlet valve (9), introducing nitrogen into the optical flow cell (2) for 10s, opening the air outlet valve (9), and repeating the action for more than 3 times to clean the optical flow cell (2); opening an air inlet valve (8), closing an air outlet valve (9), and introducing the gas to be detected for 10 seconds for sample introduction;
s2: the light source emitter (1) emits infrared light, and light with the central wavelength of the gas which is not to be measured is filtered through the filter (3);
s3: after receiving the irradiation of specific light intensity, a third pt1000 platinum resistor (4-4) and a fourth pt1000 platinum resistor (4-5) in the platinum resistor detection unit (4) generate heat change, so that resistance values are changed, the two pt1000 platinum resistors of the first pt1000 platinum resistor (4-2) and the second pt1000 platinum resistor (4-3) are subjected to physical shading and do not generate resistance value change, and a light detection signal is generated through resistance value differences between the two groups of platinum resistors of the first pt1000 platinum resistor (4-2), the second pt1000 platinum resistor (4-3), the third pt1000 platinum resistor (4-4) and the fourth pt1000 platinum resistor (4-5);
s4: the signal difference value X of the Wheatstone bridge type platinum resistor in the platinum resistor detection unit (4) is amplified through an instrument amplification circuit (5) and then amplified through a frequency-selective amplifier (6);
s5: the synchronous acquisition module (7) synchronously collects the amplified difference detection signals, and performs light intensity correction, data reference analysis and digital phase-locked frequency selection processing;
s6: calculating the concentration of the gas to be measured through linear transformation, wherein a signal difference value X after the Wheatstone bridge type platinum resistor is enhanced is obtained through the step S5, and the signal difference value X and the concentration Y of the gas to be measured satisfy a linear relation: y ═ dX + e where d, e are constants.
Priority Applications (1)
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