CN117451654A - Infrared gas sensor for detecting coal mine gas and use method thereof - Google Patents

Infrared gas sensor for detecting coal mine gas and use method thereof Download PDF

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Publication number
CN117451654A
CN117451654A CN202311220607.6A CN202311220607A CN117451654A CN 117451654 A CN117451654 A CN 117451654A CN 202311220607 A CN202311220607 A CN 202311220607A CN 117451654 A CN117451654 A CN 117451654A
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gas
absorption spectrum
detector
microprocessor
filter
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Inventor
赵涛涛
虞益挺
李文丽
赵建村
严宇超
余晓畅
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Ningbo Qipu Core Microsystem Technology Co ltd
Ningbo Research Institute of Northwestern Polytechnical University
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Ningbo Qipu Core Microsystem Technology Co ltd
Ningbo Research Institute of Northwestern Polytechnical University
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Priority to CN202311220607.6A priority Critical patent/CN117451654A/en
Publication of CN117451654A publication Critical patent/CN117451654A/en
Pending legal-status Critical Current

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504Investigating 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
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01Arrangements or apparatus for facilitating the optical investigation
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504Investigating 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
    • G01N21/3518Devices using gas filter correlation techniques; Devices using gas pressure modulation techniques
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504Investigating 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
    • G01N2021/3545Disposition for compensating effect of interfering gases

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

The invention provides an infrared gas sensor for detecting coal mine gas and a use method thereof, wherein the infrared gas sensor comprises the following steps: a mounting assembly and a housing; the mounting component is provided with a light source and a detector; the light source and the detector are connected with the microprocessor through electrical signals; four channels are arranged on the detector, and a water vapor absorption spectrum measuring filter, a methane absorption spectrum measuring filter, a sulfur dioxide absorption spectrum measuring filter and a reference absorption spectrum measuring filter are respectively arranged in the four channels; the lock of shell is on the installation component, and the mounting hole has been seted up to the upper end of shell, sets up the filter screen in the mounting hole. According to the invention, three gases can be detected simultaneously by arranging the four optical filters, so that the problem that the water vapor has strong absorptivity and the gas absorption spectrum are overlapped is solved, and the optical filter has a reference optical path, is more suitable for working in environments with various gases such as coal mines, and has higher measurement accuracy; and the device is placed in the shell, so that the volume is smaller and the manufacturing cost is cheaper.

Description

Infrared gas sensor for detecting coal mine gas and use method thereof
Technical Field
The invention relates to the technical field of infrared gas sensors for detecting coal mine gas, in particular to an infrared gas sensor for detecting coal mine gas and a using method thereof.
Background
Harmful gases in the air in the mine are generated by the gushing of coal bodies and surrounding rocks or in the production process. Among these gases, sulfur dioxide is strongly corrosive and gas is strongly explosive. For coal mines, the most hazardous gas is gas (methane as the main constituent).
The infrared absorption spectrum of the main gas (methane and sulfur dioxide) leaked from the coal mine is analyzed, and the optimal detection absorption spectrum of the sulfur dioxide can be found to be positioned at 7.17-7.58 mu m, and the highest peak value is 0.5; the optimal detection absorption spectrum of methane is located at 3.13-3.57 mu m, the highest peak value is 2.2, and meanwhile, a small absorption spectrum is located at 6.67-8 mu m, and the highest peak value is 1.0; in addition, the mine is relatively moist, contains a large amount of water vapor, and the water vapor has absorption spectra at 5-7.69 mu m and 2.5-2.78 mu m, and the highest peak values are 2.6 and 2.5 respectively. The above data shows that the absorption spectrum of methane at 6.67-8 μm (peak 1.0) affects the detection of sulfur dioxide at 7.17-7.58 μm (peak 0.5) of the absorption spectrum. The water vapor has stronger absorbability. If the target gas contains moisture (high humidity), the detection gas is affected by strong interference in the range, and even if the sensor is subjected to drying treatment, a part of water vapor possibly enters the sensor, and the absorption spectrum (peak value 2.6) of the water vapor in the range of 5-7.69 μm can influence the detection of sulfur dioxide in the absorption spectrum (peak value 0.5) in the range of 7.17-7.58 μm. (the peak values are normalized).
In the prior art, single gas detection or double gas detection with non-overlapped absorption spectrums cannot be adopted, so that the interference of gas with overlapped absorption spectrums cannot be eliminated, misjudgment is caused, and the commercial compound gas detector devices are formed by a plurality of sensors adopting different principles, so that the problems of large volume, high manufacturing cost and the like exist.
Disclosure of Invention
The invention aims to solve the problems that most of the gas detector adopts single gas detection or absorption spectrum, double gas detection without overlapping cannot eliminate the interference of gas with superimposed absorption spectrum to cause misjudgment, and some commercial compound gas detector devices are formed by a plurality of sensors adopting different principles, and have large volume and high cost.
In order to solve the above problems, the present invention provides an infrared gas sensor for detecting coal mine gas, comprising:
a mounting assembly; the installation component is internally provided with a power supply component and a microprocessor, and the power supply component is electrically connected with the microprocessor; the upper end of the mounting component is provided with a light source for emitting light and a detector for detecting; the light source and the detector are electrically connected with the microprocessor; four channels are formed in the detector, and a water vapor absorption spectrum measuring filter, a methane absorption spectrum measuring filter, a sulfur dioxide absorption spectrum measuring filter and a reference absorption spectrum measuring filter are respectively arranged in the four channels;
a housing; the lower extreme of shell is offered with four the passageway intercommunication is used for ventilative installation cavity, the lower extreme of shell connect in installation component's upper end, the upper end of shell seted up with the mounting hole that the installation cavity is linked together, be provided with in the mounting hole and be used for the filter screen.
In the scheme, three gases can be detected simultaneously by arranging the measuring water vapor absorption spectrum filter, the measuring methane absorption spectrum filter, the measuring sulfur dioxide absorption spectrum filter and the reference absorption spectrum filter, so that the problem that the water vapor has stronger absorbability and the gas absorption spectrum are overlapped is solved, and the reference channel for arranging the reference absorption spectrum filter and the reference absorption spectrum filter is used as a reference light path, so that the measuring device is more suitable for working in environments with various gases such as coal mines, and the measuring accuracy is higher; and the device is placed in the shell, so that the volume is smaller and the manufacturing cost is cheaper.
Preferably, an inner shell is arranged in the mounting cavity, a connecting cavity is formed in the lower end of the inner shell, a plurality of bosses which are arranged in a circumferential array are arranged at the upper end of the mounting assembly, and the inner shell is connected to the bosses; the light source and the detector are arranged on the inner sides of the bosses; every two adjacent bosses are provided with gaps to form an air inlet and an air outlet, a first air chamber is formed between the inner side wall of the mounting cavity and the outer side wall of the inner shell, the first air chamber is communicated with the connecting cavity through a plurality of air inlets and air outlets, and gas to be tested enters the first air chamber through the filter screen.
In the scheme, the inner shell is arranged to fix the optical path of the light emitted by the light source to the detector, so that the measurement accuracy is higher; after the gas to be tested enters the first gas chamber from the filter screen, the gas enters the connecting cavity through the gas inlet and outlet, and the next operation is waited.
As a further preference, the detector is further provided with a thermistor for monitoring and compensating the temperature.
In the scheme, the temperature compensation is performed by setting the thermistor for temperature monitoring.
As a further preference, the mounting assembly comprises a plenum floor and a circuit chamber board, the lower end of the plenum floor being connected to the upper end of the circuit chamber board, the lower end of the housing being connected to the upper end of the plenum floor; the light source and the detector are arranged on the air chamber bottom plate, the upper end of the circuit chamber plate is provided with a containing cavity, and the microprocessor and the power supply assembly are arranged in the containing cavity; the light source with the lower extreme of detector all is provided with the pin, the holding intracavity still is provided with and is used for the first pin slot that the pin of light source inserted and the second pin slot that the pin that is used for the detector inserted, first pin slot with the second pin slot all with power module electricity is connected, so that insert and locate first pin slot with in the second pin slot the light source with the detector circular telegram.
In the scheme, the bottom plate of the air chamber is used for installing a light source and a detector, and the circuit chamber board is used for installing an electric element; the first pin slot is used for inserting a light source to provide power for the light source, and the second pin slot is used for inserting a detector to provide power for the detector; the light source needs a modulation signal, and the pins of the light source are inserted into the first pin slot and can be used for alternating output; the pins of the detector are inserted into the second pin slots, so that voltage signals can be transmitted.
As a further preferable mode, a signal conditioner is further arranged in the accommodating cavity, and the signal conditioner is in electrical signal connection with the detector.
In this scheme, the signal conditioner is used for amplifying and filtering.
As a further preferred aspect, a conversion circuit is further disposed in the accommodating cavity, and the conversion circuit is electrically connected with the signal conditioner and the microprocessor respectively.
In this scheme, the conversion circuit is used for converting analog signal into digital signal.
As a further preferred aspect, the center wavelength of the measurement water vapor absorption spectrum filter is 2.6 μm±80nm; the central wavelength of the optical filter for measuring the methane absorption spectrum is 3.3 mu m +/-80 nm; the center wavelength of the sulfur dioxide absorption spectrum measuring filter is 7.3 mu m +/-80 nm; the center wavelength of the reference absorption spectrum filter is 3.0 mu m plus or minus 80nm.
A method of using an infrared gas sensor for detecting coal mine gas, comprising the infrared gas sensor for detecting coal mine gas of claim 7, further comprising the steps of:
s1, a microprocessor drives a light source to output alternating signal light;
s2, enabling the gas to be tested to enter the first gas chamber through the filter screen and then enter the connecting cavity through the gas inlet and outlet;
s3, absorbing gas infrared energy with the matched characteristic spectrums by the gas to be detected;
s4, the infrared light passes through the detected gas, and the attenuated light intensity respectively enters four channels;
s5, carrying out filtering treatment on the attenuated light intensity corresponding to the measured vapor absorption spectrum filter, the measured methane absorption spectrum filter, the measured sulfur dioxide absorption spectrum filter and the reference absorption spectrum filter which are arranged in the four channels;
s6, outputting voltages of four channels by the detector; the voltage signal enters a signal conditioner to be amplified and filtered; then converting the analog signal amplified and filtered by the signal conditioner into a digital signal through a conversion circuit;
s7, the converted digital signals enter a microprocessor to be calculated;
s8, measuring the temperature by the thermistor, feeding back the temperature to the microprocessor, and correcting the temperature by the microprocessor through a temperature compensation algorithm;
s9, simultaneously feeding back the light intensity values which are not absorbed by the gas to the microprocessor by using the channel provided with the reference absorption spectrum filter, feeding back the light intensity values of the other three channels which are absorbed by the gas to the microprocessor, and compensating the light intensity attenuation to the other three detection channels in a data form; to prevent the measurement data from being inaccurate due to the weakening of the light intensity;
s10, outputting concentration values of three gases.
Drawings
FIG. 1 is a schematic diagram of an infrared gas sensor for detecting coal mine gas according to the present invention;
FIG. 2 is a schematic diagram of the infrared gas sensor for detecting coal mine gas with the housing removed;
FIG. 3 is a schematic cross-sectional view of an infrared gas sensor for detecting coal mine gas of the present invention;
FIG. 4 is a schematic structural view of a mounting assembly of an infrared gas sensor for detecting coal mine gas according to the present invention;
FIG. 5 is a schematic view of the structure of a circuit board of an infrared gas sensor for detecting coal mine gas according to the present invention;
fig. 6 is a schematic structural diagram of an infrared gas sensor for detecting coal mine gas according to the present invention.
Reference numerals illustrate: 1. a mounting assembly; 11. a bottom plate of the air chamber; 12. a circuit chamber board; 121. a receiving chamber; 122. a first pin slot; 123. a second pin slot; 13. a power supply assembly; 14. a microprocessor; 15. a mounting port; 16. a light source; 17. a detector; 18. a channel; 181. measuring a water vapor absorption spectrum filter; 182. measuring a methane absorption spectrum filter; 183. measuring a sulfur dioxide absorption spectrum filter; 184. a reference absorption spectrum filter; 2. a housing; 21. a mounting cavity; 22. a filter screen; 3. an inner case; 31. a connecting cavity; 4. a boss; 41. an air inlet and outlet; 5. a first air chamber; 6. a signal conditioner; 7. a conversion circuit; 8. the light source is driven.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.
In accordance with the foregoing and other problems of the prior art, the present invention provides, in a preferred embodiment, an infrared gas sensor for detecting coal mine gas, as shown in fig. 1 to 6, comprising:
a mounting assembly 1; a power supply assembly 13 and a microprocessor 14 are arranged in the mounting assembly 1, and the power supply assembly 13 and the microprocessor 14 are electrically connected to provide power for the microprocessor 14; the upper end of the mounting component 1 is provided with a light source 16 for emitting light and a detector 17 for detection; and the light source 16 and the detector 17 are electrically connected with the microprocessor 14; the detector 17 is provided with four channels 18, and a water vapor absorption spectrum measuring filter 181, a methane absorption spectrum measuring filter 182, a sulfur dioxide absorption spectrum measuring filter 183 and a reference absorption spectrum filter 184 are respectively arranged in the four channels 18;
a housing 2; the lower extreme of shell 2 has seted up with four passageway 18 intercommunication and be used for the installation cavity 21 of ventilation, and the lower extreme lock of shell 2 is in the upper end of installation component 1, and the mounting hole that is linked together with installation cavity 21 is seted up to the upper end of shell 2, is provided with the filter screen 22 that is used for the inlet air or give vent to anger in the mounting hole.
The mounting assembly 1 comprises an air chamber bottom plate 11 and a circuit chamber plate 12, wherein the lower end of the air chamber bottom plate 11 is connected with the upper end of the circuit chamber plate 12, and the lower end of the shell 2 is buckled at the upper end of the air chamber bottom plate 11; the light source 16 and the detector 17 are arranged on the air chamber bottom plate 11, the upper end of the circuit chamber plate 12 is provided with a containing cavity 121, and the microprocessor 14 and the power supply assembly 13 are arranged in the containing cavity 121; the lower ends of the light source 16 and the detector 17 are respectively provided with a pin, a first pin slot 122 for inserting the pins of the light source 16 and a second pin slot 123 for inserting the pins of the detector 17 are also arranged in the accommodating cavity 121, and the first pin slot 122 and the second pin slot 123 are respectively electrically connected with the power supply assembly 13 so that the light source 16 and the detector 17 inserted in the first pin slot 122 and the second pin slot 123 are electrified.
Measuring the central wavelength of the water vapor absorption spectrum filter to be 2.6 mu m plus or minus 80nm; measuring the center wavelength of the methane absorption spectrum filter to be 3.3 mu m plus or minus 80nm; measuring the center wavelength of the sulfur dioxide absorption spectrum filter to be 7.3 mu m plus or minus 80nm; the center wavelength of the reference absorption spectrum filter 184 is 3.0 μm±80nm.
Specifically, in this embodiment, two mounting openings 15 are formed on the bottom plate 11 of the air chamber, through holes for the pins to pass through are formed on the bottom wall of the mounting opening 15, the two mounting openings 15 are respectively connected with a detector 17 and a light source 16, and the light source 16 and the detector 17 are partially protruded out of the mounting opening 15 and are positioned in the mounting cavity 21; the light source 16 is provided with an infrared emission area for emitting infrared rays; the power supply assembly 13 comprises an external interface and a data line, the external interface and the data line are connected with an upper computer (computer), and the upper computer provides power for the infrared gas sensor; by arranging the measuring water vapor absorption spectrum filter 181, the measuring methane absorption spectrum filter 182, the measuring sulfur dioxide absorption spectrum filter 183 and the reference absorption spectrum filter 184, the detection of three gases can be completed simultaneously, the problem that the strong water vapor absorption and the gas absorption spectrum overlap is eliminated, and the reference absorption spectrum filter 184 and the reference channel 18 provided with the reference absorption spectrum filter 184 are arranged as reference light paths, so that the measuring device is more suitable for working in environments with various gases such as coal mines, and the measuring accuracy is higher; and is placed in the housing 2, the volume is smaller and the cost is cheaper.
Specifically, in this embodiment, the air chamber bottom plate 11 is used for mounting the light source 16 and the detector 17, and the circuit chamber board 12 is used for mounting the electrical components; the first pin slot 122 is used for inserting the light source 16 to provide power for the light source 16, and the second pin slot 123 is used for inserting the detector 17 to provide power for the detector 17; the light source 16 needs a modulation signal, and the pins of the light source 16 are inserted into the first pin slots 122 and can be used for alternating output; the pins of the probe 17 are inserted into the second pin slots 123, so that voltage signals can be transmitted.
An inner shell 3 is arranged in the mounting cavity 21, a connecting cavity 31 is arranged at the lower end of the inner shell 3, a plurality of bosses 4 arranged in a circumferential array are arranged at the upper end of the mounting assembly 1, and the inner shell 3 is connected to the bosses 4; the light source 16 and the detector 17 are arranged on the inner sides of the bosses 4; a gap is formed between every two adjacent bosses 4 to form an air inlet and outlet 41, a first air chamber 5 is formed between the inner side wall of the mounting cavity 21 and the outer side wall of the inner shell 3, the first air chamber 5 is communicated with the connecting cavity 31 through a plurality of air inlet and outlet 41, and the gas to be tested enters the first air chamber 5 through the filter screen 22. The detector 17 is also provided with a thermistor for monitoring and compensating 17 the temperature.
Specifically, in this embodiment, the optical path from the light source to the detector can be fixed by setting the inner housing 3, so that the measurement accuracy is higher; after the gas to be measured enters the first gas chamber 5 from the filter screen 22, the gas enters the connecting cavity 31 through the gas inlet and outlet 41, and the next operation is waited. And temperature compensation is performed by arranging a thermistor for temperature monitoring.
The accommodating cavity 121 is also internally provided with a signal conditioner 6, and the signal conditioner 6 is electrically connected with the detector 17. A conversion circuit 7 is also arranged in the accommodating cavity 121, and the conversion circuit 7 is respectively and electrically connected with the signal conditioner 6 and the microprocessor 14. Specifically, in the present embodiment, the signal conditioner 6 is used for amplification filtering. The conversion circuit 7 is used to convert an analog signal into a digital signal.
Specifically, in this embodiment, the outer shell 2 and the inner shell 3 are precisely machined by stainless steel, and the inner wall of the connecting cavity 31 of the inner shell 3 and the inner wall of the mounting cavity 21 of the outer shell 2 are both arranged as light path reflecting surfaces, and the light path reflecting surfaces are spherical mirrors precisely machined by adopting the super-hydrophobic and self-cleaning coating process technology, which is favorable for reflecting emitted light rays. The light source 16 is a MEMS light source 16; the detector 17 is a MEMS thermopile, and the light source 16 is arranged at the left focus position of the connecting cavity 31; the MEMS thermopile is mounted at the right focal position of the junction chamber 31 with a thermally insulating barrier between the regions. The circuit room needs to implement gas detection circuitry, temperature compensation, and the addition of multiple sets of overlapping gas calculation and reference channel 18 contrast calculation logic. The infrared intensity of the non-dispersive infrared gas measurement sensor decreases exponentially, this relationship being called beer-lambert law I I 0 e -klx The method comprises the steps of carrying out a first treatment on the surface of the Where I denotes the outgoing light intensity, denotes the incoming light intensity, k denotes the absorption coefficient of a specific gas and filter combination, l denotes the equivalent optical path length between the light source 16 and the detector 17, and x denotes the gas concentration. The concentration of the gas was measured by beer-lambert law.
Specifically, in this embodiment, for the coal mine gas absorption spectrum, a light-emitting light source 16 (covering 2.0 μm-8 μm) covering the gas absorption spectrum is selected, the light-emitting spectrum is gentle, the light source 16 is stable, and is not easy to attenuate; the optical filters with corresponding wavelengths are formulated according to the absorption spectrum, the four optical filters are arranged in four channels 18 of the MEMS thermopile, the channels 18 provided with the reference absorption spectrum optical filters 184 can effectively eliminate the interference of external variables, so that the sensor has higher precision on the detection of gas, and meanwhile, the MEMS thermopile is provided with a thermistor to enable the thermistor to have temperature sensing, and the measurement precision can be further improved by compensating according to the temperature in the use process; according to the beer-lambert law, a longer optical path is more suitable for low gas concentration, a shorter optical path is more suitable for high gas concentration, tests are carried out on three types of gases, the optimal optical path length is tested, the housing 2, the circuit chamber board 12 and the gas chamber bottom plate 11 are all arranged in an elliptical shape, the light source 16 and the MEMS thermopile detector 17 are respectively arranged at two focuses according to the theorem that the distance from any point p on the ellipse to two focuses of the ellipse is constant, and the constant optical path is beneficial to improving the gas detection precision; the upper end of the mounting opening 15 is provided with an air inlet baffle plate and a filtering and drying device, and a heat insulation baffle plate is arranged between the areas; designing four channels 18NDIR gas detection circuits, absorbing infrared light by the gas to be detected when passing through the gas chamber, allowing infrared light with specific wavelength to pass through, converting optical signals into electric signals by the detector 17, outputting the electric signals, amplifying and filtering the electric signals by the signal conditioner 6 to amplify the signals and remove part of noise, converting analog signals into digital signals by the conversion circuit 7, and then entering an upper computer, and calibrating the change of the infrared light absorption intensity of zero points and measuring points; after the gas concentrations of the four channels 18 are measured, the gas concentrations of sulfur dioxide are obtained by processing the gas concentrations on an upper computer, converting the absorption spectrum intensities of the reference light paths of the light sources 16 according to the absorption ratios of different wave bands and differentiating the characteristic wave bands of the sulfur dioxide, so that the gas concentrations including water vapor, methane and sulfur dioxide are obtained; temperature compensation can be performed according to the feedback temperature of the thermistor.
Specifically, in this embodiment, the microprocessor 14 drives the infrared light source 16 to output an alternating signal; the detector 17 is only responsive to the alternating infrared light source 16, so that the light source 16 needs to be controlled by the microcontroller to perform alternating output; the signals output by the three detection channels 18 and one reference channel 18 of the MEMS thermopile detector 17 are voltage signals, and digital signals are output after amplified and filtered through a buffer, a programmable gain method, a modulator and a filter, and then are calculated and processed by a microcontroller; firstly, calculating the methane concentration of the spectrum at the position of 3 microns of the center wavelength and the concentration of the water vapor at the position of 2.6 microns of the center wavelength, wherein the methane concentration and the water vapor concentration of the corresponding two absorption spectrums are not overlapped with the spectrum of other coal mine gases, so that an accurate gas concentration value can be obtained; the absorption spectrum of sulfur dioxide is 7.3 microns, the absorption concentration of methane and water vapor at the wave band is calculated through the absorption ratio of the absorption spectrum, and the difference value is made between the absorption concentration and the gas concentration measured directly by the channel 18, so that the accurate sulfur dioxide concentration can be obtained; and then temperature compensation and reference channel 18 light intensity compensation are carried out, and finally the concentration values of the three gases are output.
An infrared gas sensor using method for detecting coal mine gas comprises the following steps:
s1, the microprocessor 14 drives the light source 16 to output alternating signal light;
s2, the gas to be tested enters the first gas chamber 5 through the filter screen 22 and then enters the connecting cavity 31 through the gas inlet and outlet 41;
s3, absorbing gas infrared energy with the matched characteristic spectrums by the gas to be detected;
s4, the infrared light passes through the detected gas, and the attenuated light intensity enters the four channels 18 respectively;
s5, the attenuated light intensities corresponding to the measured water vapor absorption spectrum filter 181, the measured methane absorption spectrum filter 182, the measured sulfur dioxide absorption spectrum filter 183 and the reference absorption spectrum filter 184 which are arranged in the four channels 18 are filtered;
s6, the detector 17 outputs the voltages of four channels 18; the voltage signal enters a signal conditioner 6 for amplification and filtering treatment; then converting the analog signal amplified and filtered by the signal conditioner 6 into a digital signal through the conversion circuit 7;
s7, the converted digital signals enter a microprocessor 14 for calculation processing;
s8, measuring the temperature by the thermistor, feeding back the temperature to the microprocessor 14, and correcting the temperature by the microprocessor 14 through a temperature compensation algorithm;
s9, simultaneously feeding back the light intensity values which are not absorbed by the gas to the microprocessor 14 by utilizing the channel 18 provided with the reference absorption spectrum filter 184, feeding back the light intensity values of the other three channels 18 absorbed by the gas to the microprocessor 14, and compensating the light intensity attenuation to the other three detection channels 18 in a data form; to prevent the measurement data from being inaccurate due to the weakening of the light intensity;
s10, outputting concentration values of three gases.
Although the present disclosure is described above, the scope of protection of the present disclosure is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the scope of the invention.

Claims (8)

1. An infrared gas sensor for detecting coal mine gas, comprising:
a mounting assembly (1); a power supply assembly (13) and a microprocessor (14) are arranged in the mounting assembly (1), and the power supply assembly (13) is electrically connected with the microprocessor (14); the upper end of the mounting component (1) is provided with a light source (16) for emitting light and a detector (17) for detecting; and the light source (16) and the detector (17) are electrically connected with the microprocessor (14); four channels (18) are formed in the detector (17), and a measuring water vapor absorption spectrum filter (181), a measuring methane absorption spectrum filter (182), a measuring sulfur dioxide absorption spectrum filter (183) and a reference absorption spectrum filter (184) are respectively arranged in the four channels (18);
a housing (2); the lower extreme of shell (2) is seted up with four passageway (18) intercommunication and is used for ventilative installation cavity (21), the lower extreme of shell (2) connect in the upper end of installation component (1), the upper end of shell (2) seted up with the mounting hole that installation cavity (21) are linked together, be provided with in the mounting hole and be used for filter screen (22).
2. The infrared gas sensor for detecting coal mine gas according to claim 1, wherein an inner shell (3) is arranged in the mounting cavity (21), a connecting cavity (31) is formed at the lower end of the inner shell (3), a plurality of bosses (4) arranged in a circumferential array are arranged at the upper end of the mounting assembly (1), and the inner shell (3) is connected to the bosses (4); the light source (16) and the detector (17) are arranged on the inner sides of the bosses (4); every two adjacent boss (4) between be provided with clearance formation business turn over gas port (41), be formed with first air chamber (5) between the inside wall of installation cavity (21) with the lateral wall of inner shell (3), first air chamber (5) pass through a plurality of business turn over gas port (41) with connect chamber (31) are linked together, and the gas that awaits measuring passes through filter screen (22) get into in first air chamber (5).
3. An infrared gas sensor for detecting coal mine gas according to claim 2, wherein the detector (17) is further provided with a thermistor for monitoring and compensating (17) the temperature.
4. An infrared gas sensor for detecting coal mine gas according to claim 3, wherein the mounting assembly (1) comprises a gas chamber bottom plate (11) and a circuit chamber plate (12), the lower end of the gas chamber bottom plate (11) is connected with the upper end of the circuit chamber plate (12), and the lower end of the housing (2) is connected with the upper end of the gas chamber bottom plate (11); the light source (16) and the detector (17) are arranged on the air chamber bottom plate (11), the upper end of the circuit chamber plate (12) is provided with a containing cavity (121), and the microprocessor (14) and the power supply assembly (13) are arranged in the containing cavity (121); the light source (16) with the lower extreme of detector (17) all is provided with the pin, still be provided with in holding chamber (121) and be used for first pin slot (122) that the pin of light source (16) was inserted and be used for the second pin slot (123) that the pin of detector (17) was inserted, first pin slot (122) with second pin slot (123) all with power supply unit (13) electricity is connected, so that insert locate first pin slot (122) with in second pin slot (123) light source (16) with detector (17) circular telegram.
5. The infrared gas sensor for detecting coal mine gas according to claim 4, wherein a signal conditioner (6) is further arranged in the accommodating cavity (121), and the signal conditioner (6) is electrically connected with the detector (17).
6. The infrared gas sensor for detecting coal mine gas according to claim 5, wherein a conversion circuit (7) is further arranged in the accommodating cavity (121), and the conversion circuit (7) is electrically connected with the signal conditioner (6) and the microprocessor (14) respectively.
7. The infrared gas sensor for detecting coal mine gas according to claim 6, wherein the center wavelength of the measurement water vapor absorption spectrum filter (181) is 2.6 μm±80nm; the center wavelength of the methane absorption spectrum filter (182) is 3.3 mu m plus or minus 80nm; the center wavelength of the sulfur dioxide absorption spectrum measuring filter (183) is 7.3 mu m plus or minus 80nm; the center wavelength of the reference absorption spectrum filter (184) is 3.0 mu m +/-80 nm.
8. A method of using an infrared gas sensor for detecting coal mine gas, comprising the infrared gas sensor for detecting coal mine gas of claim 7, further comprising the steps of:
s1, a microprocessor (14) drives a light source (16) to output alternating signal light;
s2, enabling gas to be detected to enter the first air chamber (5) through the filter screen (22) and then enter the connecting cavity (31) through the air inlet and outlet (41);
s3, absorbing gas infrared energy with the matched characteristic spectrums by the gas to be detected;
s4, the infrared light passes through the detected gas, and the attenuated light intensity enters four channels (18) respectively;
s5, carrying out filtering treatment on attenuated light intensity corresponding to a measured vapor absorption spectrum filter (181), a measured methane absorption spectrum filter (182), a measured sulfur dioxide absorption spectrum filter (183) and a reference absorption spectrum filter (184) which are arranged in the four channels (18);
s6, outputting voltages of four channels (18) by the detector (17); the voltage signal enters a signal conditioner (6) for amplifying and filtering treatment; then converting the analog signal amplified and filtered by the signal conditioner (6) into a digital signal through the conversion circuit (7);
s7, the converted digital signals enter a microprocessor (14) for calculation processing;
s8, measuring the temperature by the thermistor, feeding back the temperature to the microprocessor (14), and correcting the temperature by the microprocessor (14) through a temperature compensation algorithm;
s9, simultaneously feeding back the light intensity values which are not absorbed by the gas to the microprocessor (14) by utilizing the channel (18) provided with the reference absorption spectrum filter (184), feeding back the light intensity values of the other three channels (18) absorbed by the gas to the microprocessor (14), and compensating the light intensity attenuation amount to the other three detection channels (18) in a data form; to prevent the measurement data from being inaccurate due to the weakening of the light intensity;
s10, outputting concentration values of three gases.
CN202311220607.6A 2023-09-21 2023-09-21 Infrared gas sensor for detecting coal mine gas and use method thereof Pending CN117451654A (en)

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Citations (4)

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Publication number Priority date Publication date Assignee Title
CN206235556U (en) * 2016-05-17 2017-06-09 杭州麦乐克科技股份有限公司 A kind of infrared composite gas sensor
CN108489924A (en) * 2018-03-13 2018-09-04 南京信息工程大学 A kind of sensing probe and non-dispersive infrared gas sensor detecting system
CN111929269A (en) * 2020-09-23 2020-11-13 上海翼捷工业安全设备股份有限公司 Three-channel infrared methane detector resistant to water vapor interference
US20220307976A1 (en) * 2021-03-29 2022-09-29 Asahi Kasei Microdevices Corporation Optical concentration measuring device, module for optical concentration measuring device and optical concentration measuring method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN206235556U (en) * 2016-05-17 2017-06-09 杭州麦乐克科技股份有限公司 A kind of infrared composite gas sensor
CN108489924A (en) * 2018-03-13 2018-09-04 南京信息工程大学 A kind of sensing probe and non-dispersive infrared gas sensor detecting system
CN111929269A (en) * 2020-09-23 2020-11-13 上海翼捷工业安全设备股份有限公司 Three-channel infrared methane detector resistant to water vapor interference
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