CN111896476B - Gas concentration detection sensor - Google Patents
Gas concentration detection sensor Download PDFInfo
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- CN111896476B CN111896476B CN202010816775.1A CN202010816775A CN111896476B CN 111896476 B CN111896476 B CN 111896476B CN 202010816775 A CN202010816775 A CN 202010816775A CN 111896476 B CN111896476 B CN 111896476B
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- 238000001514 detection method Methods 0.000 title claims abstract description 20
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 22
- 239000000741 silica gel Substances 0.000 claims description 22
- 229910002027 silica gel Inorganic materials 0.000 claims description 22
- 239000003292 glue Substances 0.000 claims description 20
- 238000002347 injection Methods 0.000 claims description 17
- 239000007924 injection Substances 0.000 claims description 17
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 6
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- 238000005498 polishing Methods 0.000 claims description 6
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- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
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- 238000005259 measurement Methods 0.000 abstract description 5
- 230000000694 effects Effects 0.000 abstract description 3
- 238000010895 photoacoustic effect Methods 0.000 abstract description 3
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- 238000004867 photoacoustic spectroscopy Methods 0.000 description 6
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- 238000009529 body temperature measurement Methods 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/1702—Systems in which incident light is modified in accordance with the properties of the material investigated with opto-acoustic detection, e.g. for gases or analysing solids
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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
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
- G01N21/03—Cuvette constructions
- G01N21/0303—Optical path conditioning in cuvettes, e.g. windows; adapted optical elements or systems; path modifying or adjustment
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- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
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- 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 relates to a gas concentration detection sensor, and belongs to the field of gas sensors. The gas concentration detection sensor comprises a gas chamber component, a light source, a lens component, a microphone, an opening and closing component and a circuit board, wherein the microphone is arranged at the top of the gas chamber component, the light source, the lens component, the microphone and the opening and closing component are arranged on the circuit board, the gas chamber component is provided with a concave lens wall with a concave lens structure, the opening and closing component is provided with a gas chamber door plate, a spring and an electromagnet, and the spring and the electromagnet produce a tensile force effect to enable the gas chamber door plate to reciprocate, so that the gas chamber component generates and cancels a closed gas chamber. The air flow disturbance generated during the air pumping of the common air sensor can be avoided, the noise caused by the air flow disturbance is reduced, and the measurement precision is improved; the full-light area can be formed in the closed air chamber, the utilization rate of light energy is improved, the active quantity of air molecules in the closed air chamber can be improved, and the intensity of acoustic signals generated by the photoacoustic effect is further improved.
Description
Technical Field
The invention relates to a gas concentration detection sensor, in particular to a method for measuring the concentration of specific gas by utilizing a photoacoustic spectroscopy technology, belonging to the field of gas sensors.
Background
The photoacoustic spectrum gas detection is realized by utilizing the principle of photoacoustic conversion effect and weak signal detection technology, and the main principle is as follows: when a beam of specific monochromatic light is injected into a container filled with a gas to be tested at a fixed frequency f, if the wavelength of the incident light is within the absorption range of the gas to be tested, the incident light is absorbed by the gas to be tested, and sound waves with the same period as the modulation frequency, namely the photoacoustic effect, are generated. The detected acoustic wave signal is converted into an electrical signal that can be processed by a microphone, and the concentration of the detected gas can be calculated by analyzing the detected electrical signal.
The common methods for detecting the gas concentration are a non-optical method and an optical method, wherein the non-optical method mainly comprises an electrochemical method, a thermocatalysis method and the like; the optical method mainly includes absorption spectroscopy, photoacoustic spectroscopy, and the like. With the increasing sensitivity of the microphone in recent years, the photoacoustic spectroscopy technology has been rapidly developed, and the use of photoacoustic spectroscopy to detect the concentration of gas has become a mainstream trend. When the photoacoustic spectrometry is used for detecting the concentration of the gas, the gas to be detected does not need to be preprocessed, and the concentration of the gas can be determined directly through the detected acoustic wave signals.
However, the current method for measuring the concentration of a specific gas by using the photoacoustic spectroscopy technology has certain drawbacks. Firstly, light emission and an air chamber are unreasonable in structure, so that the light energy utilization rate is low; secondly, the structural design of the inlet of the ventilation pump is unreasonable, gas flows in and out of the air chamber, noise signals can be generated, the stability can be recovered after waiting for a long time, the detection precision can be affected, and the detection duration is prolonged.
Disclosure of Invention
Aiming at the problems that the light energy utilization rate is low and gas flows due to gas inlet and outlet into and out of the gas chamber, the invention provides a gas concentration detection sensor.
The invention is realized by the following technical scheme: the gas concentration detection sensor comprises a gas chamber component, a light source, a lens component, a microphone, an opening and closing component and a circuit board, wherein the light source and the lens component are arranged on one side of the gas chamber component, the microphone is arranged on the top of the gas chamber component, the light source, the lens component, the microphone and the opening and closing component are arranged on the circuit board, the gas chamber component is provided with a concave lens wall with a concave lens structure, the opening and closing component is provided with a gas chamber door plate, a spring and an electromagnet, the opening and closing component is connected with the gas chamber component in a matched manner through the gas chamber door plate, light reflected by the concave lens wall with the concave lens structure forms a full light area in the gas chamber, and the spring and the electromagnet exert a tensile force to enable the gas chamber door plate to reciprocate, so that the gas chamber component generates and cancels the closed gas chamber.
The air chamber component is provided with an air chamber main body, an air chamber inner plate, silica gel, vent holes, an air chamber outer plate and a concave lens wall, wherein the air chamber main body is a cavity square body without front and rear walls, the bottom surface wall of the air chamber main body is arranged on a circuit board, the top surface wall and the bottom surface wall of the air chamber main body at the inner side of the cavity are divided into the air chamber inner plate and the air chamber outer plate, the air chamber inner plate is far away from the outer surfaces of the top surface wall and the bottom surface wall compared with the air chamber outer plate, a height difference is formed between the air chamber inner plate and the air chamber outer plate, the silica gel is arranged on two outer edges of the air chamber inner plate, the vent holes are formed in the air chamber main body, the positions of the vent holes are arranged on the air chamber outer plate and the side wall, the central long section of the vent holes at the same side are on one plane, the vent hole positions do not influence the air chamber component to produce a closed air chamber, the side wall of the air chamber is arranged on one side wall of the air chamber main body, the filter is penetratingly arranged on the side wall of the air chamber main body, the other side wall is a concave lens wall, the concave lens structure is arranged on one side of the cavity side of the air chamber main body, the microphone is arranged on the top surface of the air chamber main body, and the probe is arranged in the main body;
The light source and the lens component are provided with a light source, a light source installation shell, a lens and a light filter, wherein the light source is installed at the detail part of the light source installation shell, the light filter is installed in one side wall of the air chamber main body in a penetrating mode, the thick part of the light source installation shell is connected to the outer side of the side wall of the air chamber main body, on which the light filter is installed, the lens is installed inside the light source installation shell and is located between the light source and the light filter, and the surface centers of the light source, the lens and the light filter, on the cross section in the direction perpendicular to the bottom surface of the circuit board, are on the same straight line.
Including but not limited to convex lenses and fresnel lenses.
The opening and closing component is provided with an air chamber door plate, an opening and closing support frame, a spring, a magnetic block and an electromagnet, wherein the air chamber door plate which can be matched and connected with the air chamber main body is installed at one end of the opening and closing support frame, the spring and the magnetic block are installed at one end of the opening and closing support frame, the electromagnet is fixedly installed on a circuit board, magnetic force is generated when the electromagnet is electrified, the elastic force of the spring is overcome, the opening and closing support frame is attracted to be close to and adsorbed, a closed air chamber generated by the air chamber component is opened, the magnetic force is lost when the electromagnet is powered off, the opening and closing support frame is close to the air chamber main body under the action of the spring, the opening and closing support frame is clamped with silica gel, and the closed air chamber is generated in the air chamber component.
The inner surface of the air chamber main body, the inner plate of the air chamber, the inner surface of the concave lens wall and the inner surface of the air chamber door plate are made of mirror surface materials and/or are plated with mirror surface plating layers and/or are subjected to mirror surface polishing, the mirror surface materials comprise but are not limited to mirror surface aluminum alloy and mirror surface stainless steel, the mirror surface plating layers comprise but are not limited to chemical nickel plating layers, and the mirror surface polishing means that the surface roughness value Ra is less than or equal to Ra.; the concave lens structure combined with the concave lens wall can form a full light area in the closed air chamber.
The circuit board is provided with a power supply circuit, a calculation control circuit, a light source driving circuit and a signal processing circuit, wherein the signal processing circuit comprises a differential amplifying circuit and a frequency-selecting amplifying circuit; the P end of the power supply circuit is connected with a battery for supplying power to the light source, the microphone, the electromagnet, the calculation control circuit, the light source driving circuit and the signal processing circuit;
The calculation control circuit is provided with a singlechip; the P end of the light source driving circuit is connected with the light source, is provided with a high-speed optical coupler and an enhanced field effect transistor, and can be matched with PWM waves to drive the light source; the P end of the differential amplifying circuit is connected with a microphone and is provided with an amplifier, so that weak signals output by the microphone can be properly amplified; the frequency-selecting amplifying circuit is provided with a multiplier and a low-pass filter, and can filter out high-frequency signals.
The circuit board is provided with a temperature measuring module, and measured ambient temperature data are transmitted to the singlechip.
The opening and closing component is provided with an air chamber door plate, an opening and closing supporting frame, a spring, a magnetic block, an electromagnet, an avoidance groove, steel balls, a bead limiting plate and a glue injection hole, wherein the air chamber door plate which can be connected with the air chamber main body in a matching way is arranged at one end of the opening and closing supporting frame, the avoidance groove is arranged at one end of the air chamber door plate arranged at the opening and closing supporting frame, and the avoidance groove can avoid interference between the opening and closing supporting frame and the air chamber main body;
The upper surface and the lower surface of the air chamber door plate are provided with a plurality of spherical pits, steel balls are arranged in the spherical pits, the bead limiting plate is provided with a plurality of spherical pits which correspond to the positions and the number of the air chamber door plate, the positions which correspond to the positions on the upper surface and the lower surface of the air chamber door plate are provided with glue injection holes, the air chamber door plate and the bead limiting plate are arranged together through glue injection holes by using adhesive glue, after the air chamber door plate and the bead limiting plate are arranged together, the steel balls exceed a part of the outer surface of the bead limiting plate, the steel balls can freely rotate, the other end of the opening and closing support frame is provided with a spring and a magnetic block, an electromagnet is fixedly arranged on a circuit board, the electromagnet generates magnetic force when electrified, overcomes the elasticity of the spring, attracts the opening and closing support frame to close and adsorb the closed air chamber generated by the air chamber component, the electromagnet loses the magnetic force when electrified, the opening and closing support frame is close to the air chamber body under the action of the spring to clamp with silica gel, and the closed air chamber is generated in the air chamber component.
The air chamber component is provided with an air chamber main body, an air chamber inner plate, silica gel, an air chamber outer plate, a supporting plate, side guard plates and concave lens walls, wherein the air chamber main body is a cavity square body without front and rear walls, the bottom wall of the air chamber main body is arranged on a circuit board, the top wall and the bottom wall of the air chamber main body at the inner side of the cavity are divided into the air chamber inner plate and the air chamber outer plate, the air chamber inner plate is far away from the outer surfaces of the top wall and the bottom wall compared with the air chamber outer plate, a height difference is formed between the air chamber inner plate and the air chamber outer plate, the silica gel is arranged on the two outer edges of the air chamber inner plate, the supporting plate is arranged at the middle position of the air chamber outer plate, and the side guard plates are arranged at the two sides of the outer end of the supporting plate;
The microphone is characterized in that an optical filter is arranged on one side wall of the air chamber main body in a penetrating way, the other side wall of the air chamber main body is a concave lens wall, the concave lens wall is of a concave lens structure on one side of the cavity, the microphone is arranged on the top wall of the air chamber main body in a penetrating way, and the microphone probe is arranged in the air chamber main body.
The opening and closing component is provided with an air chamber door plate, an opening and closing support frame, a spring, a magnetic block, an electromagnet, a connecting block, a bead limiting plate, steel balls and glue injection holes, wherein one end of the opening and closing support frame is connected with the connecting block, the other end of the connecting block is provided with the air chamber door plate which can be connected with an air chamber main body in a matched mode, a plurality of spherical pits are formed in the outer side face of the connecting block, the steel balls are arranged in the spherical pits, the bead limiting plate is provided with a plurality of spherical pits which correspond to the connecting block in positions and quantity, glue injection holes are formed in the outer side face of the connecting block and the positions corresponding to the bead limiting plate, the air chamber door plate and the bead limiting plate are installed together through glue injection holes, the steel balls exceed a part of the outer surface of the bead limiting plate after the air chamber door plate and the bead limiting plate are installed together, the steel balls can rotate freely, the other end of the opening and closing support frame is provided with a spring and a magnetic block, the electromagnet is fixedly installed on a circuit board, the elasticity of the spring is overcome, the opening and closing support frame is close to the air chamber component is attracted, the closed when the electromagnet is powered off, the magnetic force is lost, the air chamber is closed under the action of the spring, the air chamber door is closed, the air chamber door is clamped with the air chamber door plate, and the air chamber door is clamped with the air chamber, and the part and the closed.
The invention has the advantages that the invention can avoid the air flow disturbance generated when the air of the common air sensor is pumped, reduce the noise caused by the air flow disturbance and improve the measurement precision; the full-light region can be formed in the closed air chamber, the utilization rate of light energy is improved, the active quantity of air molecules in the closed air chamber can be improved, and the intensity of acoustic signals generated by the photoacoustic effect is further improved; the power consumption of the sensor can be reduced by electromagnet driving and mechanical structure transmission; the arrangement of the silica gel can assist in forming a closed air chamber, can play a role in buffering, and can avoid collision between the rotating plate and the air chamber main body to generate vibration; the temperature compensation can be realized by the arrangement of the temperature sensor; the concentration of different gases can be measured by using different filters to select light rays with different wavelengths; the steel balls can reduce contact area, friction and unnecessary movement noise, and can assist movement, so that the air chamber door plate does not incline and movement is smooth.
Drawings
FIG. 1 is a schematic view showing the structure of a closed air chamber according to embodiment 1 of the present invention;
FIG. 2 is an isometric view of a closed air chamber according to embodiment 1 of the present invention;
FIG. 3 is a schematic view showing the structures of part of the air chamber part and part of the light source and lens part of embodiment 1 of the present invention;
FIG. 4 is a top view of a part of the plenum member and a part of the light source and lens member of embodiment 1 of the present invention;
fig. 5 is a schematic structural view of an opening and closing member according to embodiment 1 of the present invention;
FIG. 6 is a schematic view showing the structure of the closed air chamber according to embodiment 2 of the present invention;
FIG. 7 is a schematic view showing the structures of part of the gas cell unit and part of the light source and lens unit of embodiment 2 of the present invention;
fig. 8 is a schematic structural view of an opening and closing member according to embodiment 2 of the present invention;
Fig. 9 is an elevation view of an opening and closing member of embodiment 2 of the present invention;
FIG. 10 is a schematic view showing the structure of the closed air chamber according to embodiment 3 of the present invention;
FIG. 11 is an isometric view of a closed cell according to example 3 of the present invention;
FIG. 12 is a schematic view showing the structures of part of the air cell component and part of the light source and lens component of embodiment 3 of the present invention;
FIG. 13 is a front view of a part of the air cell component and a part of the light source and lens component of embodiment 3 of the present invention;
fig. 14 is a schematic structural view of an opening and closing member according to embodiment 3 of the present invention;
fig. 15 is a front-rear side view of the opening-closing member of embodiment 3 of the present invention;
FIG. 16 is an elevation view of an opening and closing member of embodiment 3 of the present invention;
FIG. 17 is a power supply circuit diagram;
FIG. 18 is a diagram of a calculation control circuit;
FIG. 19 is a light source driving circuit diagram;
fig. 20 is a differential amplification circuit diagram;
fig. 21 is a frequency-selective amplifying circuit diagram.
In fig. 1 to 5, 1, a gas cell part, 101, a gas cell main body, 102, a gas cell inner plate, 103, silica gel, 104, a vent hole, 105, a gas cell outer plate, 106, a concave lens wall, 2, a light source and lens part, 201, a light source, 202, a light source mounting case, 203, a lens, 204, a filter, 3, a microphone, 301, a microphone probe, 4, an opening and closing part, 401, a gas cell door plate, 402, an opening and closing support frame, 403, a spring, 404, a magnetic block, 405, an electromagnet, 5, and a circuit board.
In fig. 6 to 9, 21, a gas cell member, 2101, a gas cell main body, 2102, a gas cell inner plate, 2103, silica gel, 2104, a vent hole, 2105, a gas cell outer plate, 2106, a concave lens wall, 22, a light source and lens member, 2201, a light source, 2202, a light source mounting case, 2203, a lens, 2204, an optical filter, 23, a microphone, 24, an opening and closing member, 2401, a gas cell door plate, 2402, an opening and closing support frame, 2403, a spring, 2404, a magnetic block, 2405, an electromagnet, 2406, an avoidance groove, 2407, a steel ball, 2408, a bead limiting plate, 2409, a glue injection hole, 25, and a circuit board.
In fig. 10 to 16, 31, a gas cell member, 3101, a gas cell main body, 3102, a gas cell inner plate, 3103, a silica gel, 3104, a gas cell outer plate, 3105, a support plate, 3106, a side shield, 3017, a concave lens wall, 32, a light source and a lens member, 3201, a light source, 3202, a light source mounting case, 3203, a lens, 3204, a filter, 33, a microphone, 3301, a microphone probe, 34, an opening and closing member, 3401, a gas cell door plate, 3402, an opening and closing support frame, 3403, a spring, 3404, a magnetic block, 3405, an electromagnet, 3406, a connection block, 3407, a bead limiting plate, 3408, a steel ball, 3409, a glue injection hole, 35, and a circuit board.
Detailed Description
Example 1
As shown in the attached figures 1-5, the gas concentration detection sensor comprises a gas chamber component 1, a light source and a lens component 2, a microphone 3, an opening and closing component 4 and a circuit board 5, wherein the light source and the lens component 2 are arranged on one side of the gas chamber component 1, the microphone 3 is arranged at the top of the gas chamber component 1, the gas chamber component, the light source and the lens component, the microphone and the opening and closing component 4 are arranged on the circuit board 5, the gas chamber component 1 is provided with a concave lens wall with a concave lens structure, the opening and closing component is provided with a gas chamber door plate, a spring and an electromagnet, the opening and closing component is connected with the gas chamber component through the gas chamber door plate in a matched manner, light reflected by the concave lens wall with the concave lens structure forms a full-light area in the gas chamber, and the spring and the electromagnet produce a tension effect to enable the gas chamber door plate to reciprocate, so that the gas chamber component 1 generates and cancels a closed gas chamber.
As shown in fig. 3 and fig. 4, the air chamber component 1 has an air chamber main body 101, an air chamber inner plate 102, silica gel 103, a vent 104, an air chamber outer plate 105 and a concave lens wall 106, wherein the air chamber main body 101 is a hollow square body without front and rear walls, the bottom wall of the air chamber main body 101 is mounted on the circuit board 5, the top wall and the bottom wall of the air chamber main body 101 at the inner side of the hollow space are divided into the air chamber inner plate 102 and the air chamber outer plate 105, the air chamber inner plate 102 is far away from the outer surfaces of the top wall and the bottom wall than the air chamber outer plate 105, a height difference is formed between the air chamber inner plate 102 and the air chamber outer plate 105, the silica gel 103 is mounted on two outer edges of the air chamber inner plate 102, the vent 104 is opened on the air chamber main body 101, the position of the vent 104 is arranged on the air chamber outer plate 105 and the side wall, the central long section of the vent 104 at the same side is on one plane, the position of the vent 104 does not influence the air chamber component 1 to generate a closed air chamber, the filter 204 is mounted on one side wall of the air chamber main body in a penetrating way, the other side wall is the concave lens wall 106, the concave lens wall 106 is a concave lens structure at one side of the hollow space, the air chamber main body is a concave lens structure, the air chamber is formed at the side, the side of the air chamber main body, the microphone 3 is mounted on the microphone 101, and penetrates through the air chamber main body 301;
As shown in fig. 1-4, the light source and lens component 2 has a light source 201, a light source mounting case 202, a lens 203 and a filter 204, wherein the light source is mounted on a detail of the light source mounting case 202, the filter is mounted in a side wall of the air chamber main body 101 in a penetrating manner, a thick part of the light source mounting case 202 is connected to an outer side of the side wall of the air chamber main body 101 on which the filter is mounted, the lens is mounted inside the light source mounting case 202 and is positioned between the light source and the filter, and the light source 201, the lens 203 and a surface center of a cross section of the filter 204 in a direction perpendicular to a bottom surface of the circuit board are aligned.
The lens 203 includes, but is not limited to, a convex lens and a fresnel lens.
As shown in fig. 1, fig. 2 and fig. 5, the opening and closing component 4 is provided with an air chamber door plate 401, an opening and closing support frame 402, a spring 403, a magnetic block 404 and an electromagnet 405, one end of the opening and closing support frame 402 is provided with the air chamber door plate 401 which can be connected with the air chamber main body 101 in a matching way, one end of the opening and closing support frame 402 is provided with the spring 403 and the magnetic block 404, the electromagnet 405 is fixedly arranged on the circuit board 5, magnetic force is generated when the electromagnet 405 is electrified, the elastic force of the spring is overcome, the opening and closing support frame 402 is attracted to be close to and adsorbed, so that a closed air chamber generated by the air chamber component 1 is opened, the magnetic force is lost when the electromagnet 405 is powered off, the opening and closing support frame 402 is close to the air chamber main body 101 under the action of the spring and is clamped with the silica gel 103, and the closed air chamber is generated in the air chamber component 1.
The inner surface of the air chamber main body 101, the inner surface of the air chamber inner plate 102, the inner surface of the concave lens wall 106 and the inner surface of the air chamber door plate 401 are made of mirror surface materials and/or are plated with mirror surface coatings and/or are subjected to mirror surface polishing, the mirror surface materials comprise but are not limited to mirror surface aluminum alloy and mirror surface stainless steel, the mirror surface coatings comprise but are not limited to electroless nickel plating, and the mirror surface polishing means that the surface roughness value Ra is less than or equal to Ra0.2; the concave lens structure in combination with the concave lens wall 106 may form a plenoptic zone within the enclosed plenum.
17-21, The circuit board is provided with a power supply circuit, a calculation control circuit, a light source driving circuit and a signal processing circuit, wherein the signal processing circuit comprises a differential amplifying circuit and a frequency-selecting amplifying circuit; the P1 end of the power supply circuit is connected with a battery for supplying power to the light source 201, the microphone 3, the electromagnet 405, the calculation control circuit, the light source driving circuit and the signal processing circuit;
The calculation control circuit is provided with a singlechip; the P2 end of the light source driving circuit is connected with the light source, is provided with a high-speed optical coupler and an enhanced field effect transistor, and can be matched with PWM waves to drive the light source; the P3 end of the differential amplifying circuit is connected with a microphone and is provided with an amplifier, so that weak signals output by the microphone can be properly amplified; the frequency-selecting amplifying circuit is provided with a multiplier and a low-pass filter, and can filter out high-frequency signals.
The circuit board 5 is provided with a temperature measuring module, and measured ambient temperature data are transmitted to the singlechip.
The temperature change can cause measurement errors, and the singlechip is combined with the temperature data measured by the temperature measurement module to correct the measured gas concentration data, so that the measurement errors caused by the temperature change are compensated.
The working process of the invention is that a control circuit on a circuit board 5 controls the opening and closing part 4 to work so as to control the air chamber part 1 to open the air chamber cavity to form an open space, so that the air to be measured enters the air chamber cavity of the air chamber part 1; after the opening and closing component 4 works for a specific time, the control circuit controls the opening and closing component 4 to further control the air chamber component 1 to seal the inner cavity of the air chamber to form a sealed space, then a singlechip of the control circuit outputs PWM waves with specific time and specific frequency to control the frequency of light emitted by the light source, then the lens is used for refracting the light to obtain parallel light, and then the wavelength of the incident light is selected through the optical filter, so that the central wavelength of the incident light can completely scan the absorption line of the gas to be detected in the air chamber; the incident light enters the air chamber, passes through the gas to be detected, is reflected by the convex mirror, and is reflected by the inner side surface of the wall of the air chamber, and finally a uniform light field is formed in the air chamber, so that the gas to be detected in the air chamber fully absorbs light energy; the gas molecules to be detected undergo transition after absorbing light energy, thermal motion is aggravated, acoustic signals are generated, the microphone collects and converts the acoustic signals into electric signals, the collected electric signals are subjected to differential amplification, frequency selection amplification and noise filtering through the signal processing circuit, the electric signals are transmitted to the singlechip, the singlechip analyzes and calculates the signals according to a preset program, and the singlechip refers to prestored reference data to output gas concentration values.
The working process of the opening and closing part 4 is as follows: the electromagnet 405 is electrified to generate magnetic force, the magnetic force overcomes the elasticity of the spring 403, the magnetic block 404 on the opening and closing support frame 402 is attracted to be close to the electromagnet 405, the air chamber door plate 401 is restrained by the shape of the air chamber outer plate 105, and only the air chamber can be opened by linear reciprocating motion along with the opening and closing support frame 402. When the electromagnet 405 is powered off, the magnetic block 404 is far away from the electromagnet 405 by the elastic force of the spring 403, so that the air chamber door plate 401 compresses the silica gel 103, and the air chamber is closed.
Taking the measurement of NH 3 gas concentration as an example, a filter is selected to enable light with the wavelength of about 1531.6nm to pass through, a single chip microcomputer is used for generating PWM signals, the frequency of light source modulation signals generating 1160Hz is further controlled, and the NH 3 gas concentration is measured according to the parameters.
During research and development, the system physical noise interference signals generated in the using process are detected through experiments, the characteristic parameters of the noise interference signals and the change rule of the characteristic parameters under the influence of variables such as temperature, gas concentration and the like are obtained through algorithm and data learning, and then the influence of the noise interference signals is eliminated during data processing.
In the actual use process, even if silica gel is arranged, noise signals caused by collision are generated between the air chamber door plate 401 and the air chamber main body 101, errors are generated on the detection of the acoustic signals, the single chip can analyze and calculate the acoustic signals measured by the microphone for multiple times within a specific time to obtain the calculated effective values of the acoustic signals, and corresponding concentration values are obtained through calculation and retrieval of early experimental data. During research and development, acoustic signal amplitude values detected by corresponding microphones of a plurality of concentration values are obtained through a large number of experiments, and a fitting curve corresponding to the data is obtained through a genetic algorithm. The singlechip processes the detected acoustic signals by utilizing the pre-obtained data, and searches and calculates the corresponding concentration value
Example 2
As shown in fig. 6-9, compared with embodiment 1, the present embodiment solves the problem that in embodiment 1, the air chamber door plank 2401 is easy to be locked due to the engagement and tilting during the reciprocating movement, and is characterized in that the opening and closing component 24 has an air chamber door plank 2401, an opening and closing support frame 2402, a spring 2403, a magnetic block 2404, an electromagnet 2405, an avoidance groove 2406, a steel ball 2407, a bead limiting plate 2408 and a glue injection hole 2409, one end of the opening and closing support frame 2402 is provided with the air chamber door plank 2401 capable of being cooperatively connected with the air chamber main body 2101, the avoidance groove 2406 is opened at one end of the air chamber door plank 2401 provided with the opening and closing support frame 2402, and the avoidance groove can avoid the interference between the opening and closing support frame and the air chamber main body 2101;
The upper surface and the lower surface of the air chamber door plank 2401 are provided with a plurality of spherical pits, steel balls 2407 are arranged in the spherical pits, the ball limiting plate 2408 is provided with a plurality of spherical pits which correspond to the positions and the number of the air chamber door plank 2401, the upper surface and the lower surface of the air chamber door plank 2401 and the positions which correspond to the ball limiting plate 2408 are provided with glue injection holes 2409, the air chamber door plank 2401 and the ball limiting plate 2408 are arranged together through glue injection holes 2409, after the air chamber door plank 2401 and the ball limiting plate 2408 are arranged together, the steel balls 2407 extend out of a part of the outer surface of the ball limiting plate 2408, the steel balls 2407 can freely rotate, the other end of the opening and closing support frame 2402 is provided with a spring 2403 and a magnetic block 2404, an electromagnet 2405 is fixedly arranged on a circuit board 25, when the electromagnet 2405 is electrified, magnetic force is generated, the elasticity of the spring is overcome, the opening and closing support frame 2402 is attracted to be close to and adsorbed, when the electromagnet 2405 is disconnected, the magnetic force is lost when the electromagnet 2402 is powered off, the air chamber 2101 is closed under the action of the spring, the air chamber 2103, the air chamber element 21 is clamped in the air chamber 2103, and the air chamber 21 is closed.
In the process of reciprocating the air chamber door plank 2401, steel balls 2407 on the upper surface and the lower surface of the air chamber door plank 2401 are in contact with the air chamber outer plate 2105, and sliding friction between the air chamber door plank 401 and the air chamber outer plate 105 in the embodiment 1 is converted into rolling friction through rolling of the steel balls 2407, so that stable movement of the air chamber door plank 2401 is realized; to accommodate the widening of the air chamber door panel 401 to become the air chamber door panel 2401 in embodiment 1, the air chamber outer panel 2105 is correspondingly widened as compared to the air chamber outer panel 105 in embodiment 1.
Example 3
As shown in fig. 10 to 16, this embodiment solves the problems of the embodiment 2 that the ventilation efficiency is not high due to the narrow ventilation hole 2104 and the steel balls 2407 are easily stuck in the ventilation hole 2104, compared with the embodiment 2, except that,
The air chamber component 1 comprises an air chamber main body 3101, an air chamber inner plate 3102, silica gel 3103, an air chamber outer plate 3104, a supporting plate 3105, side guard plates 3106 and concave lens walls 3017, wherein the air chamber main body 3101 is a square cavity body without front and rear walls, the bottom wall of the air chamber main body 3101 is arranged on a circuit board 35, the top surface wall and the bottom surface wall of the air chamber main body 3101 inside the cavity are divided into an air chamber inner plate 3102 and an air chamber outer plate 3104, the air chamber inner plate 3102 is far away from the outer surfaces of the top surface wall and the bottom surface wall than the air chamber outer plate 3104, a height difference is formed between the air chamber inner plate 3102 and the air chamber outer plate 3104, the silica gel 3103 is arranged on two outer edges of the air chamber inner plate 3102, the supporting plate 3105 is arranged at the middle position of the air chamber outer plate 3104, and the side guard plates 3106 are arranged on two sides of the outer end of the supporting plate 3105;
the filter 3204 is installed on one side wall of the air chamber body in a penetrating way, the concave lens wall 3107 is arranged on the other side wall of the air chamber body, the concave lens wall 3107 is of a concave lens structure on one side of the cavity, the microphone 33 is installed on the top wall of the air chamber body 3101 in a penetrating way, and the microphone probe 3301 is arranged in the air chamber body 3101.
The opening and closing component 34 is provided with an air chamber door plate 3401, an opening and closing support frame 3402, a spring 3403, a magnetic block 3404, an electromagnet 3405, a connecting block 3406, a bead limiting plate 3407, steel balls 3408 and glue injection holes 3409, wherein one end of the opening and closing support frame 3402 is connected with the connecting block 3406, the other end of the connecting block 3406 is provided with the air chamber door plate 3401 which can be matched and connected with the air chamber main body 3101, the outer side surface of the connecting block 3406 is provided with a plurality of spherical pits, steel balls 3408 are arranged in the spherical pits, the bead limiting plate 3407 is provided with a plurality of spherical pits corresponding to the positions and the numbers of the connecting block 3406, the outer side surface of the connecting block 3406 and the positions corresponding to the bead limiting plate 3407 are provided with glue injection holes 3409, the air chamber door panel 3401 and the bead limiting plate 3407 are installed together through the glue injection hole 3409 by using glue, after the air chamber door panel 3401 and the bead limiting plate 3407 are installed together, the steel balls 3408 exceed a part of the outer surface of the bead limiting plate 3407, the steel balls 3408 can rotate freely, the other end of the opening and closing support frame 3402 is provided with a spring 3403 and a magnetic block 3404, an electromagnet 3405 is fixedly installed on a circuit board 35, magnetic force is generated when the electromagnet 3405 is electrified, the elasticity of the spring is overcome, the opening and closing support frame 3402 is attracted to be close to and adsorbed, a closed air chamber generated by the air chamber component 31 is opened, the magnetic force is lost when the electromagnet 3405 is powered off, the opening and closing support frame 3402 is close to the air chamber main body 3101 under the action of the spring and is clamped with the silica gel 3103, and the closed air chamber is generated in the air chamber component 31.
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art in a specific case.
Alterations, modifications, substitutions and variations of the embodiments herein will be apparent to those of ordinary skill in the art in light of the teachings of the present invention without departing from the spirit and principles of the invention.
Claims (6)
1. The gas concentration detection sensor comprises a gas chamber component, a light source, a lens component, a microphone, an opening and closing component and a circuit board, wherein the light source and the lens component are arranged on one side of the gas chamber component, the microphone is arranged at the top of the gas chamber component, and the gas chamber component, the light source, the lens component, the microphone and the opening and closing component are arranged on the circuit board, and the gas concentration detection sensor is characterized in that: the air chamber component is provided with a concave lens wall with a concave lens structure, the opening and closing component is provided with an air chamber door plate, a spring and an electromagnet, the opening and closing component is connected with the air chamber component through the air chamber door plate in a matched manner, the concave lens wall with the concave lens structure reflects light rays to form a full light area in the air chamber, and the spring and the electromagnet generate a tensile force to enable the air chamber door plate to reciprocate, so that the air chamber component generates and cancels a closed air chamber;
The air chamber component is provided with an air chamber main body, an air chamber inner plate, silica gel, vent holes, an air chamber outer plate and a concave lens wall, wherein the air chamber main body is a cavity square body without front and rear walls, the bottom surface wall of the air chamber main body is arranged on a circuit board, the top surface wall and the bottom surface wall of the air chamber main body at the inner side of the cavity are divided into the air chamber inner plate and the air chamber outer plate, the air chamber inner plate is far away from the outer surfaces of the top surface wall and the bottom surface wall compared with the air chamber outer plate, a height difference is formed between the air chamber inner plate and the air chamber outer plate, the silica gel is arranged on two outer edges of the air chamber inner plate, the vent holes are formed in the air chamber main body, the positions of the vent holes are arranged on the air chamber outer plate and the side wall, the central long section of the vent holes at the same side are on one plane, the vent hole positions do not influence the air chamber component to produce a closed air chamber, the side wall of the air chamber is arranged on one side wall of the air chamber main body, the filter is penetratingly arranged on the side wall of the air chamber main body, the other side wall is a concave lens wall, the concave lens structure is arranged on one side of the cavity side of the air chamber main body, the microphone is arranged on the top surface of the air chamber main body, and the probe is arranged in the main body;
The light source and the lens component are provided with a light source, a light source installation shell, a lens and a light filter, wherein the light source is installed at the detail part of the light source installation shell, the light filter is installed in one side wall of the air chamber main body in a penetrating way, the thick part of the light source installation shell is connected to the outer side of the side wall of the air chamber main body, on which the light filter is installed, the lens is installed inside the light source installation shell and is positioned between the light source and the light filter, and the light source, the lens and the surface center of the cross section of the light filter in the direction perpendicular to the bottom surface of the circuit board are in the same straight line;
The opening and closing component is provided with an air chamber door plate, an opening and closing supporting frame, a spring, a magnetic block, an electromagnet, an avoidance groove, steel balls, a bead limiting plate and a glue injection hole, wherein the air chamber door plate which can be connected with the air chamber main body in a matching way is arranged at one end of the opening and closing supporting frame, the avoidance groove is arranged at one end of the air chamber door plate arranged at the opening and closing supporting frame, and the avoidance groove can avoid interference between the opening and closing supporting frame and the air chamber main body;
The upper surface and the lower surface of the air chamber door plate are provided with a plurality of spherical pits, steel balls are arranged in the spherical pits, the bead limiting plate is provided with a plurality of spherical pits which correspond to the positions and the number of the air chamber door plate, the positions which correspond to the positions on the upper surface and the lower surface of the air chamber door plate are provided with glue injection holes, the air chamber door plate and the bead limiting plate are arranged together through glue injection holes by using adhesive glue, after the air chamber door plate and the bead limiting plate are arranged together, the steel balls exceed a part of the outer surface of the bead limiting plate, the steel balls can freely rotate, the other end of the opening and closing support frame is provided with a spring and a magnetic block, an electromagnet is fixedly arranged on a circuit board, the electromagnet generates magnetic force when electrified, overcomes the elasticity of the spring, attracts the opening and closing support frame to close and adsorb the closed air chamber generated by the air chamber component, the electromagnet loses the magnetic force when electrified, the opening and closing support frame is close to the air chamber body under the action of the spring to clamp with silica gel, and the closed air chamber is generated in the air chamber component.
2. The gas concentration detection sensor according to claim 1, wherein: the lens includes a convex lens and a fresnel lens.
3. The gas concentration detection sensor according to claim 1, wherein: the opening and closing component is provided with an air chamber door plate, an opening and closing support frame, a spring, a magnetic block and an electromagnet, wherein the air chamber door plate which can be matched and connected with the air chamber main body is installed at one end of the opening and closing support frame, the spring and the magnetic block are installed at one end of the opening and closing support frame, the electromagnet is fixedly installed on a circuit board, magnetic force is generated when the electromagnet is electrified, the elastic force of the spring is overcome, the opening and closing support frame is attracted to be close to and adsorbed, a closed air chamber generated by the air chamber component is opened, the magnetic force is lost when the electromagnet is powered off, the opening and closing support frame is close to the air chamber main body under the action of the spring, the opening and closing support frame is clamped with silica gel, and the closed air chamber is generated in the air chamber component.
4. The gas concentration detection sensor according to claim 1, wherein: the inner surface of the air chamber main body, the inner plate of the air chamber, the inner surface of the concave lens wall and the inner surface of the air chamber door plate are made of mirror surface materials and/or are plated with mirror surface coatings and/or are subjected to mirror surface polishing, the mirror surface materials comprise mirror surface aluminum alloy and mirror surface stainless steel, the mirror surface coatings comprise chemical nickel plating layers, and the mirror surface polishing means that the surface roughness value Ra is less than or equal to Ra0.2; the concave lens structure combined with the concave lens wall can form a full light area in the closed air chamber.
5. The gas concentration detection sensor according to claim 1, wherein: the circuit board is provided with a power supply circuit, a calculation control circuit, a light source driving circuit and a signal processing circuit, wherein the signal processing circuit comprises a differential amplifying circuit and a frequency-selecting amplifying circuit; the P end of the power supply circuit is connected with a battery for supplying power to the light source, the microphone, the electromagnet, the calculation control circuit, the light source driving circuit and the signal processing circuit;
The calculation control circuit is provided with a singlechip; the P end of the light source driving circuit is connected with the light source, is provided with a high-speed optical coupler and an enhanced field effect transistor, and can be matched with PWM waves to drive the light source; the P end of the differential amplifying circuit is connected with a microphone and is provided with an amplifier, so that weak signals output by the microphone can be properly amplified; the frequency-selecting amplifying circuit is provided with a multiplier and a low-pass filter, and can filter out high-frequency signals.
6. The gas concentration detection sensor according to claim 5, wherein: the circuit board is provided with a temperature measuring module, and measured ambient temperature data are transmitted to the singlechip.
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