CN110361352B - Gas concentration detection device with double channels, detection method and alarm device - Google Patents

Gas concentration detection device with double channels, detection method and alarm device Download PDF

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Publication number
CN110361352B
CN110361352B CN201910751799.0A CN201910751799A CN110361352B CN 110361352 B CN110361352 B CN 110361352B CN 201910751799 A CN201910751799 A CN 201910751799A CN 110361352 B CN110361352 B CN 110361352B
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light
mounting
channel
gas
gas concentration
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CN110361352A (en
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卿笃安
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Shenzhen Noan Intelligent Co ltd
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Shenzhen Noan Intelligent Co ltd
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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
    • 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
    • G01N21/031—Multipass arrangements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/255—Details, e.g. use of specially adapted sources, lighting or optical systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
    • 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
    • G01N2021/0106—General arrangement of respective parts
    • G01N2021/0112—Apparatus in one mechanical, optical or electronic block
    • 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
    • G01N21/031—Multipass arrangements
    • G01N2021/0314—Double pass, autocollimated path
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

The invention provides a gas concentration detection device with two channels, a detection method and an alarm device. By arranging the concave reflecting mirror, the light intensity reaching the double-channel detector can be improved, and the sensitivity of the double-channel detector is further improved.

Description

Gas concentration detection device with double channels, detection method and alarm device
Technical Field
The invention relates to the technical field of gas concentration monitoring, in particular to a gas concentration detection device with double channels, a detection method and an alarm device.
Background
The infrared combustible gas monitoring alarm device has the advantages of long service life, good reliability, high detection precision and the like, is favored by users, and is especially suitable for application occasions with high requirements on service life and reliability.
Because the sampling mode of the alarm device generally needs to adopt a diffusion type structure, and the mid-far infrared spectrum is a linear light source, effective collimation is difficult, light energy of light emitted by the light source is scattered, the light energy is scattered after reflection, and the detector needs to have extremely high sensitivity.
In the prior art, pyroelectric materials are generally adopted as detectors, and a specific optical filter is additionally arranged in front of the detectors. Because of weak light energy, a large window single-channel pyroelectric detector is required to meet the requirements. In the prior art, a light splitting sheet is generally arranged in an emission light path, and reflected light energy is averagely sent to two single-channel detectors for detection.
The method has the advantages of complex receiving structure, large detection light path adjustment error and lower light energy intensity, thereby leading to more detection interference factors and lower detection precision of the alarm device.
Disclosure of Invention
The invention mainly provides a gas concentration detection device with double channels, a detection method and an alarm device, so as to improve the detection precision of the gas concentration detection device with double channels.
In order to solve the technical problems, the invention adopts a technical scheme that: the utility model provides a gas concentration detection device with binary channels, gas concentration detection device with binary channels includes light source, concave mirror and binary channels detector, the light that the light source sent shines to the concave mirror, concave mirror gathers and reflects light extremely the binary channels detector, the binary channels detector is including being located detection channel and the reference channel on same horizontal plane, the detection channel is used for detecting the first luminous intensity of the first wavelength light after being absorbed by gas, the reference channel is used for detecting the second luminous intensity of the second wavelength light that is not absorbed by gas, through first luminous intensity with the second luminous intensity obtains the concentration of gas.
In order to solve the technical problems, the invention adopts another technical scheme that: provided is a detection method including: controlling the light source to periodically emit light; controlling a concave reflector to focus and reflect emergent light of the light source to a dual-channel detector, wherein the dual-channel detector comprises a detection channel and a reference channel, the detection channel is used for detecting first light intensity of first wavelength light absorbed by gas, and the reference channel is used for detecting second light intensity of second wavelength light not absorbed by gas; and responding to the corresponding relation between the ratio of the first light intensity to the second light intensity and the concentration of the gas to be detected, and obtaining the concentration of the gas to be detected.
In order to solve the technical problems, the invention adopts another technical scheme that: there is provided an alarm device comprising an alarm and a gas concentration detection device with two channels as described above, the alarm being electrically connected to the gas concentration detection device with two channels for emitting an alarm sound when the gas concentration detection device with two channels detects that the concentration of combustible gas is greater than a preset value.
The beneficial effects of the invention are as follows: according to the invention, the concave reflector is arranged, so that the light intensity reaching the dual-channel detector can be improved, the sensitivity of the dual-channel detector is further improved, the detection channel and the reference channel in the dual-channel detector are arranged on the same horizontal plane, the incident light entering the detection channel and the reference channel can be uniform, the compensation error is further reduced, the differential operation processing is carried out on the first light intensity of the detection channel and the second light intensity of the reference channel, the light source power fluctuation and the reflection loss factor interference are eliminated, and the gas concentration measurement result is obtained.
Drawings
For a clearer description of the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the description below are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art, wherein:
FIG. 1 is a schematic perspective view of a gas concentration detection apparatus with dual channels according to an embodiment of the present invention;
FIG. 2 is a schematic cross-sectional view of the gas concentration detection apparatus of FIG. 1 having two channels;
FIG. 3 is a schematic perspective view of the adaptive reflector of FIG. 2;
FIG. 4 is a schematic process flow diagram of an adaptive reflector according to an embodiment of the invention;
FIG. 5 is a schematic perspective view of the mounting cylinder of FIG. 2;
FIG. 6 is a schematic perspective view of the mounting base of FIG. 2;
FIG. 7 is a schematic diagram of an exploded view of the mount of FIG. 2 with a light source and dual channel detector;
FIG. 8 is a schematic view of the partial enlarged structure of FIG. 2;
FIG. 9 is a schematic perspective view of the mounting cylinder of FIG. 2;
fig. 10 is a flow chart of a detection method in an embodiment of the invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the prior art, pyroelectric materials are generally adopted as detectors, and a specific optical filter is additionally arranged in front of the detectors. Because of weak light energy, a large window single-channel pyroelectric detector is required to meet the requirements. In the prior art, a light splitting sheet is generally arranged in an emission light path, and reflected light energy is averagely sent to two single-channel detectors for detection. The method has the advantages of complex receiving structure, large detection light path adjustment error and lower light energy intensity, thereby leading to more detection interference factors and lower detection precision of the alarm device.
By arranging the concave reflecting mirror, the light intensity reaching the double-channel detector can be improved, and the sensitivity of the double-channel detector is further improved. In addition, the detection channel and the reference channel are arranged on the same horizontal plane, so that incident light can be uniform, compensation errors are reduced, and the detection precision of the gas concentration detection device with two channels is improved.
Referring to fig. 1 and 2, fig. 1 is a schematic perspective view of a gas concentration detecting device with two channels according to an embodiment of the invention, and fig. 2 is a schematic cross-sectional view of the gas concentration detecting device with two channels according to the embodiment of the invention. The gas concentration detection apparatus 100 with two channels includes a light source 10, a concave mirror 40, and a two-channel detector 30, wherein light emitted from the light source 10 irradiates the concave mirror 40, the concave mirror 40 converges and reflects the light to the two-channel detector 30, the two-channel detector 30 includes a detection channel and a reference channel on the same horizontal plane, the detection channel is used for detecting a first light intensity of a first wavelength light absorbed by a gas, the reference channel is used for detecting a second light intensity of a second wavelength light not absorbed by the gas, and the concentration of the gas is obtained through the first light intensity and the second light intensity. The detection channel and the reference channel are positioned on the same horizontal plane, so that incident light entering the detection channel and the reference channel can enter simultaneously, further compensation errors are reduced, and the detection precision of the gas concentration detection device 100 with two channels is improved.
In this embodiment, under the same light and gas action distance, the change of the light intensity differential signal of the dual-channel detector 30 increases with the increase of the gas concentration, so that a mathematical relationship curve of one-to-one correspondence between the gas concentration and the light intensity differential signal of the detector is established, and the gas concentration sensing measurement is realized, thus forming the dual-channel detector 30. Meanwhile, the integrated dual-channel detector 30 is adopted to detect the first wavelength light and the second wavelength light simultaneously, so that the first wavelength light and the second wavelength light have the same source and propagation path, and the light intensity disturbance and the light loss caused by the external environment, reflection scattering and the like are the same, therefore, the light intensity dynamic disturbance caused by the light source intensity fluctuation and the propagation loss can be effectively eliminated by utilizing the differential signal processing of the two, and the detection precision of the dual-channel gas concentration detection device 100 is further improved.
According to the embodiment of the invention, the concave reflecting mirror 40 is arranged, so that the light intensity reaching the dual-channel detector 30 can be improved, the sensitivity of the dual-channel detector 30 is further improved, and the incident light entering the detection channel and the reference channel can be simultaneously entered by arranging the detection channel and the reference channel in the dual-channel detector 30 on the same horizontal plane, so that the compensation error is reduced, and the detection precision of the gas concentration detection device 100 with dual channels is improved.
In the present embodiment, the gas concentration detection apparatus 100 having two channels includes a first narrowband filter provided in the detection channel and a second narrowband filter provided in the reference channel. Light entering the detection channel is filtered by the first narrow-band filter to obtain first-wavelength light, light entering the reference channel is filtered by the second narrow-band filter to obtain second-wavelength light, and the first-wavelength light can be absorbed by gas and the second-wavelength light cannot be absorbed by the gas. By arranging the first narrow-band optical filter and the second narrow-band optical filter, the detection spectrum band can be flexibly selected.
Wherein the fact that the second wavelength light is not absorbed by the gas means that in an ideal case the gas does not have the capacity to absorb the second wavelength light, i.e. in an ideal case the energy of the second wavelength light does not change after the second wavelength light has passed through the gas.
Specifically, in this embodiment, the light source is a mid-infrared light source emitting a wavelength band between 3000 nm and 7000 nm, and light in this wavelength band is more easily absorbed by the gas to be detected, for example, the absorption intensity of methane to light with a wavelength of 3310nm is 200 times that of light with a wavelength of 1670nm, so that the detection accuracy of the gas concentration detection apparatus with multiple channels is improved. The center wavelength of the first wavelength light may be set to 3200nm to 3400nm, and the light of this wavelength band is more easily absorbed by methane, for example, the absorption intensity of methane to light of wavelength 3310nm is 200 times that of light of wavelength 1670nm, thereby improving the detection accuracy of the dual-channel detector 30. The center wavelength of the first wavelength light may be set to 4200nm to 4300nm, and the light of this wavelength band is more easily absorbed by carbon dioxide. The center wavelength of the first wavelength light may be set to 4600nm to 4700nm, and light in this wavelength band is more easily absorbed by carbon monoxide. The center wavelength of the second wavelength light may be set to 3930nm to 3950nm, and light of this wavelength band is not easily absorbed by the gas.
Because the gas to be measured has a strong absorption effect on the first wavelength light, but the gas to be measured has no absorption effect on the second wavelength light, when the emergent light of the light source 10 passes through the gas region to be measured, the energy of the first wavelength light is reduced, but the energy of the second wavelength light is not changed basically, so that the first light intensity corresponding to the energy of the first wavelength light and the second light intensity corresponding to the energy of the second wavelength light can be obtained, and further, the concentration of the gas to be measured can be obtained through calculation of the first light intensity and the second light intensity.
In this embodiment, under the same light and gas action distance, the change of the light intensity differential signal of the dual-channel detector 30 increases with the increase of the gas concentration, so that a mathematical relationship curve of one-to-one correspondence between the gas concentration and the light intensity differential signal of the detector is established, and the gas concentration sensing measurement is realized, thus forming the dual-channel detector 30. Meanwhile, the integrated dual-channel detector 30 is adopted to detect the first wavelength light and the second wavelength light simultaneously, so that the first wavelength light and the second wavelength light have the same source and propagation path, and the light intensity disturbance and the light loss caused by the external environment, reflection scattering and the like are the same, therefore, the light intensity dynamic disturbance caused by the light source intensity fluctuation and the propagation loss can be effectively eliminated by utilizing the differential signal processing of the two, and the detection precision of the dual-channel gas concentration detection device 100 is further improved.
Optionally, in an embodiment, the light reflected and emitted by the adaptive light reflecting member 20 may be parallel light, so as to reduce the diffusion of the light, avoid the light contacting the obstacle during the transmission process, and make a larger proportion of the light incident on the dual-channel detector 30, thereby improving the light energy utilization rate of the light source 10.
In this embodiment, the opening angle of the light reflected and emitted by the adaptive light reflecting member 20 is set to be smaller than 15 °, where the opening angle of the light refers to: the maximum angle between the direction of the light and the direction of the light emitted from the light source 10. By setting the opening angle of the light to be smaller than 15 °, the processing precision of the reflective surface 221 can be reduced while satisfying the higher light energy utilization rate, and further the processing cost can be reduced.
Further, as shown in fig. 2, 5 and 6, the gas concentration detection apparatus 100 having a dual channel further includes a mounting cylinder 50 and a mounting seat 60, the mounting cylinder 50 having opposite first and second ends 51 and 53. The mount 60 is connected to the first end 51 of the mounting barrel 50, and the light source 10 and the dual channel detector 30 are disposed on the mount 60. The concave mirror 40 is disposed at the second end 53 of the mounting barrel 50. Through setting up mount pad 60 to offer light source mounting hole 62 and detector mounting hole 64 simultaneously on mount pad 60, with being used for installing light source 10 and binary channels detector 30, can make the structure compacter, and can fix light source 10 and binary channels detector 30 simultaneously through an element, and then reduced the quantity of element, and also reduced the installation complexity, be convenient for install and dismantle. By providing the mounting cylinder 50, the light source 10, the concave mirror 40, and the dual-channel detector 30 can be integrated, facilitating installation.
Further, as shown in fig. 2 and 6, the mounting base 60 is provided with a light source mounting hole 62 and a detector mounting hole 64, the light source 10 is assembled in the light source mounting hole 62, the dual-channel detector 30 is assembled in the detector mounting hole 64, and the axis of the light source mounting hole 62 and the axis of the detector mounting hole 64 are symmetrically arranged about the axis of the mounting cylinder 50, so that the light focused by the concave reflector 40 can vertically enter the dual-channel detector 30, and the utilization rate of light energy is improved.
Alternatively, in this embodiment, as shown in fig. 2 and 5, the mounting cylinder 50 includes a mounting portion 52 and a cylinder portion 54, the cylinder portion 54 is hollow and is connected to one side of the mounting portion 52, a mounting groove 522 is formed on a surface of the mounting portion 52 away from the cylinder portion 54, the mounting seat 60 is accommodated in the mounting groove 522, the light source 10 and the dual-channel detector 30 are fixed on the mounting seat 60, and the concave mirror 40 is disposed on one side of the cylinder portion 54 away from the mounting portion 52. An avoidance hole 524 which is communicated with the installation groove 522 and the inside of the cylinder 54 is formed in the bottom of the installation groove 522, light rays emitted by the light source 10 enter the concave reflector 40 through the avoidance hole 524, and the light rays converged and reflected by the concave reflector 40 enter the dual-channel detector 30 through the avoidance hole 524.
Further, as shown in fig. 2 and 8, the cylinder 54 has a detection chamber 55 formed therein, and the gas concentration detection apparatus 100 having two channels further includes a separation mirror 80, where the separation mirror 80 is sandwiched between the bottom wall of the mounting groove 522 and the mounting seat 60, and is used to cover the avoidance hole 524 to separate the detection chamber 55 from the mounting groove 522. In this embodiment, by providing the isolation mirror 80 for isolating the detection cavity 55 from the mounting groove 522, the gas in the detection cavity 55 can be prevented from entering the mounting groove 522, so as to avoid the gas to be detected from contacting the electrical parts of the light source 10 and the dual-channel detector 30 and exploding, thereby improving the safety performance of the gas concentration detection apparatus 100 with dual channels.
Referring to fig. 10, fig. 10 is a flow chart of a detection method according to an embodiment of the invention. The invention also provides a detection method, which comprises the following steps:
s201: controlling the light source 10 to periodically emit light;
s202: controlling the concave mirror 40 to focus and reflect the outgoing light of the light source 10 to the dual-channel detector 30, wherein the dual-channel detector 30 comprises a detection channel for detecting a first light intensity of a first wavelength light absorbed by the gas and a reference channel for detecting a second light intensity of a second wavelength light not absorbed by the gas;
S203: and responding to the corresponding relation between the ratio of the first light intensity and the second light intensity and the concentration of the gas to be detected, and obtaining the concentration of the gas to be detected.
In this embodiment, the light emission frequency of the light source 10 is 1-10HZ. For example, it may be 1HZ, 2HZ, 3HZ, 4HZ, 5HZ, 6HZ, 7HZ, 8HZ, 9HZ, 10HZ or the like. The setting may be performed according to the kind of the gas to be measured and the concentration of the gas to be measured, and the embodiment of the present invention is not particularly limited.
Under the same light and gas action distance, the change of the light intensity differential signal of the dual-channel detector 30 is increased along with the increase of the gas concentration, so that a mathematical relationship curve of one-to-one correspondence between the gas concentration and the light intensity differential signal of the detector is established, gas concentration sensing measurement is realized, and the dual-channel detector 30 is formed. Meanwhile, the integrated dual-channel detector 30 is adopted to detect the first wavelength light and the second wavelength light simultaneously, so that the first wavelength light and the second wavelength light have the same source and propagation path, and the light intensity disturbance and the light loss caused by the external environment, reflection scattering and the like are the same, therefore, the light intensity dynamic disturbance caused by the light source intensity fluctuation and the propagation loss can be effectively eliminated by utilizing the differential signal processing of the two, and the detection precision of the dual-channel gas concentration detection device 100 is further improved.
The invention also provides an alarm device, which comprises an alarm and a gas concentration detection device with two channels, wherein the alarm is electrically connected with the gas concentration detection device with two channels and is used for giving out an alarm sound when the gas concentration detection device with two channels detects that the concentration of the combustible gas is greater than a preset value.
In this embodiment, the structure of the gas concentration detection apparatus with two channels is the same as the structure of the gas concentration detection apparatus 100 with two channels in the above embodiment, please refer to the description in the above embodiment, and the description is omitted here. The preset value of the concentration of the combustible gas can be set according to the explosion-proof requirement, and the embodiment of the invention is not particularly limited.
Referring to fig. 1 and 2, fig. 1 is a schematic perspective view of a gas concentration detecting device with two channels according to an embodiment of the invention, and fig. 2 is a schematic cross-sectional view of the gas concentration detecting device with two channels according to the embodiment of the invention. The gas concentration detection device 100 with two channels comprises a light source 10, a concave reflector 40, a two-channel detector 30 and a mounting seat 60, wherein a light source mounting hole 62 and a detector mounting hole 64 are formed in the mounting seat 60, the light source 10 is assembled in the light source mounting hole 62, the two-channel detector 30 is assembled in the detector mounting hole 64, the concave reflector 40 and the mounting seat 60 are oppositely arranged, light emitted by the light source 10 irradiates the concave reflector 40, and the concave reflector 40 gathers and reflects the light to the two-channel detector 30.
According to the embodiment of the invention, the mounting seat 60 is arranged, and the light source mounting hole 62 and the detector mounting hole 64 are simultaneously formed in the mounting seat 60 and are used for mounting the light source 10 and the double-channel detector 30, so that the structure is more compact, the light source 10 and the double-channel detector 30 can be simultaneously fixed through one element, the number of elements is further reduced, the mounting complexity is also reduced, the mounting and the dismounting are convenient, and the mounting precision is improved.
Further, as shown in fig. 2, the gas concentration detection apparatus 100 having two channels further includes a mounting cylinder 50, the mounting cylinder 50 having opposite first and second ends 51, 53. The mounting base 60 is connected to the first end 51 of the mounting barrel 50, and the concave mirror 40 is disposed at the second end 53 of the mounting barrel 50. By providing the mounting cylinder 50, the light source 10, the concave mirror 40, and the dual-channel detector 30 can be integrated, facilitating installation.
Alternatively, as shown in fig. 2, the axis of the light source mounting hole 62 and the axis of the detector mounting hole 64 are disposed obliquely with respect to the axis of the mounting cylinder 50.
In this embodiment, as shown in fig. 2, the axis of the light source mounting hole 62 and the axis of the detector mounting hole 64 are symmetrically arranged about the axis of the mounting barrel 50, so that the light focused by the concave mirror 40 can vertically enter the dual-channel detector 30, thereby improving the utilization rate of light energy.
Further, as shown in fig. 2 and 5, fig. 5 is a schematic perspective view of the mounting cylinder in fig. 2. The mounting cylinder 50 comprises a mounting part 52 and a cylinder body 54, the cylinder body 54 is arranged in a hollow mode and is connected to one side of the mounting part 52, a mounting groove 522 is formed in the surface, far away from the cylinder body 54, of the mounting part 52, a mounting seat 60 is accommodated in the mounting groove 522, the light source 10 and the dual-channel detector 30 are fixed on the mounting seat 60, and the concave reflector 40 is arranged on one side, far away from the mounting part 52, of the cylinder body 54. An avoidance hole 524 which is communicated with the installation groove 522 and the inside of the cylinder 54 is formed in the bottom of the installation groove 522, light rays emitted by the light source 10 enter the concave reflector 40 through the avoidance hole 524, and the light rays converged and reflected by the concave reflector 40 enter the dual-channel detector 30 through the avoidance hole 524.
In this embodiment, as shown in fig. 2, 5 and 6, fig. 6 is a schematic perspective view of the mounting base in fig. 2. The mounting groove 522 is a step groove, and the step groove includes first recess 521 and second recess 523 of nested setting, and first recess 521 nestification is in the bottom of second recess 523, dodges the hole 524 and is located the bottom surface of first recess 521. The mount 60 includes a fixing portion 61 and a connecting portion 63, and a light source mounting hole 62 and a detector mounting hole 64 are opened in the fixing portion 61. The fixing portion 61 is accommodated in the first groove 521, and the connecting portion 63 is fixedly connected to the bottom surface of the second groove 523. By arranging the mounting groove 522 as a step groove, on one hand, the mounting seat 60 is convenient to limit, and the mounting seat 60 is prevented from moving; on the other hand, the axial length of the mounting seat 60 and the mounting cylinder 50 can be shortened, so that the structure is more compact and the volume is smaller.
In this embodiment, the fixing portion 61 and the connecting portion 63 are integrally formed, however, in other embodiments, the fixing portion 61 and the connecting portion 63 may be detachably connected, which is not particularly limited.
Alternatively, in the present embodiment, the mounting groove 522 is provided as a circular groove, the connection portion 63 is annular, and the annular connection portions 63 are provided on opposite sides of the fixing portion 61. By providing the annular connecting portion 63, the volume of the connecting portion 63 can be reduced, and further, other elements can be conveniently arranged in the mounting groove 522, so that the structure is more compact and the volume is smaller.
Further, as shown in fig. 2, the gas concentration detecting apparatus 100 with dual channels further includes an adaptive reflector 20, the adaptive reflector 20 is assembled in the light source mounting hole 62, the surface of the adaptive reflector 20 is provided with a reflective groove 22, the sidewall of the reflective groove 22 forms a reflective surface 221, and the light source 10 is installed in the center of the reflective groove 22.
Specifically, in the present embodiment, the reflective cavity 22 is a groove with an opening, and the light emitted from the light source 10 is emitted through the opening. The groove is horn-shaped and is used for converging and then emitting light.
Fig. 4 is a schematic process flow of the adaptive reflector according to an embodiment of the invention, as shown in fig. 4. The adaptive reflector 20 may be manufactured by the following manufacturing steps:
S101: the filament shape dimensions of the plurality of light sources 10 are counted.
S102: modeling is performed with the filament shape dimensions of the light source 10 to obtain an optimal shape curve for the reflective surface 221.
S103: the reflection groove 22 is processed on the adaptive reflection member 20 by using an optimal shape curve of the reflection surface 221, the sidewall of the reflection groove 22 is polished, and an oxidation-preventing protective film 24 is coated on the sidewall of the polished reflection groove 22.
In this embodiment, the anti-oxidation protective film 24 may be an aluminum reflective film, however, in other embodiments, other types of anti-oxidation protective films 24 may be electroplated or coated as needed, for example: 50-200 nm gold film, 50-200 nm silver film, 100-200 nm titanium dioxide film, 100-200 nm vanadium pentoxide film, 100-200 nm silicon dioxide film, 100-200 nm magnesium fluoride film, 100-200 nm silicon nitride film, these types of films not only prevent oxidation but also have high reflectivity. The anti-oxidation protective film 24 coated on the sidewall of the reflective trough 22 can prevent the sidewall of the reflective trough 22 from being oxidized, thereby improving the reflectivity of the reflective surface 221 and reducing the optical loss.
By shielding the adaptive light reflecting member 20 outside the light source 10, the light emitted from the light source 10 can be collimated, so as to improve the light intensity of the light emitted from the light source 10, reduce the light loss in the light transmission process, and further improve the light intensity incident to the dual-channel detector 30.
Further, as shown in fig. 7, fig. 7 is a schematic diagram of an exploded structure of the mount, the light source and the dual-channel detector in fig. 2. The wall of the detector mounting hole 64 and the outer wall of the dual-channel detector 30 are respectively provided with a limit groove 642 and a limit post 32 which are matched with each other. Through setting up spacing post 32 and spacing groove 642 of mutually supporting between the pore wall of binary channels detector 30 and detector mounting hole 64, can be convenient for fix a position binary channels detector 30, prevent that binary channels detector 30 from rotating in detector mounting hole 64, and then promote the connection stability of binary channels detector 30 and self-adaptation reflector 20.
Further, the mounting base 60 is provided with a fixing hole 65, and the gas concentration detecting device 100 with two channels further comprises a temperature sensor 70, wherein the temperature sensor 70 is arranged in the fixing hole 65.
Specifically, as shown in fig. 7, a fixing hole 65 is formed on the surface of the mounting seat 60 facing away from the mounting cylinder 50, and a temperature sensor 70 is disposed in the fixing hole 65 for detecting the temperature of the circuit board in the dual-channel detector 30 and sending a prompt when detecting that the temperature of the circuit board is high, so as to prevent the gas concentration detecting device 100 with dual channels from being damaged due to the excessive temperature.
Alternatively, in the present embodiment, the fixing hole 65 is a blind hole formed on the mounting base 60, and the temperature sensor 70 may be fixed in the fixing hole 65 by an adhesive or a screw, etc., so as to improve the integration of the gas concentration detection apparatus 100 having two channels and reduce the volume of the gas concentration detection apparatus 100 having two channels. Of course, in other embodiments, the fixing hole 65 may be provided as a through hole, and embodiments of the present invention are not particularly limited.
In this embodiment, the light source is a mid-infrared light source emitting light in a wavelength band between 3000 nm and 7000 nm, and the light in this wavelength band is more easily absorbed by the gas to be detected, for example, the absorption intensity of methane to light with a wavelength of 3310nm is 200 times that of light with a wavelength of 1670nm, so that the detection accuracy of the gas concentration detection device with multiple channels is improved. The center wavelength of the first wavelength light may be set to 3200nm to 3400nm, and the light of this wavelength band is more easily absorbed by methane, for example, the absorption intensity of methane to light of wavelength 3310nm is 200 times that of light of wavelength 1670nm, thereby improving the detection accuracy of the dual-channel detector 30. The center wavelength of the first wavelength light may be set to 4200nm to 4300nm, and the light of this wavelength band is more easily absorbed by carbon dioxide. The center wavelength of the first wavelength light may be set to 4600nm to 4700nm, and light in this wavelength band is more easily absorbed by carbon monoxide. The center wavelength of the second wavelength light may be set to 3930nm to 3950nm, and light of this wavelength band is not easily absorbed by the gas.
The invention also provides an alarm device, which comprises an alarm and a gas concentration detection device with two channels, wherein the alarm is electrically connected with the gas concentration detection device with two channels and is used for giving out an alarm sound when the gas concentration detection device with two channels detects that the concentration of the combustible gas is greater than a preset value.
In this embodiment, the structure of the gas concentration detection apparatus with two channels is the same as the structure of the gas concentration detection apparatus 100 with two channels in the above embodiment, please refer to the description in the above embodiment, and the description is omitted here. The preset value of the concentration of the combustible gas can be set according to the explosion-proof requirement, and the embodiment of the invention is not particularly limited.
Referring to fig. 1 and 2, fig. 1 is a schematic perspective view of a gas concentration detecting device with two channels according to an embodiment of the invention, and fig. 2 is a schematic cross-sectional view of the gas concentration detecting device with two channels according to the embodiment of the invention. The gas concentration detection device 100 with the double channels comprises a light source 10, a concave mirror 40, a double-channel detector 30, an isolation mirror 80 and a mounting cylinder 50, wherein the mounting cylinder 50 is provided with a mounting groove 522, a detection cavity 55 and an avoidance hole 524 communicated with the mounting groove 522 and the detection cavity 55, the detection cavity 55 is used for containing gas to be detected, the light source 10 and the double-channel detector 30 are arranged in the mounting groove 522, the concave mirror 40 is arranged in the detection cavity 55, the isolation mirror 80 covers the avoidance hole 524 to isolate the detection cavity 55 and the mounting groove 522, light emitted by the light source 10 irradiates the concave mirror 40 through the avoidance hole 524, and light converged and reflected by the concave mirror 40 enters the double-channel detector 30 through the avoidance hole 524.
According to the embodiment of the invention, the isolation mirror 80 covering the avoidance hole 524 is arranged, so that the installation groove 522 provided with the light source 10 and the double-channel detector 30 can be isolated from the detection cavity 55 for accommodating the gas to be detected, and the gas in the detection cavity 55 can be prevented from entering the installation groove 522, so that the gas to be detected is prevented from being in contact with the electric parts of the light source 10 and the double-channel detector 30 to cause explosion, and the safety performance of the gas concentration detection device 100 with double channels is further improved.
In this embodiment, the isolation mirror 80 can allow infrared light to penetrate, so as to detect the concentration of the gas to be detected in the infrared light range, thereby avoiding the influence of ambient light and improving the detection accuracy.
Alternatively, the isolation mirror 80 may be a sapphire lens, a calcium fluoride lens, a silicon wafer, or the like, and embodiments of the present invention are not particularly limited.
Further, as shown in fig. 2 and 6, the gas concentration detecting apparatus 100 with two channels further includes a mounting base 60, the mounting base 60 is disposed in the mounting groove 522, the mounting base 60 is provided with a light source mounting hole 62 and a detector mounting hole 64, the light source 10 is assembled in the light source mounting hole 62, and the two-channel detector 30 is assembled in the detector mounting hole 64. Through setting up mount pad 60 to offer light source mounting hole 62 and detector mounting hole 64 simultaneously on mount pad 60, with being used for installing light source 10 and binary channels detector 30, can make the structure compacter, and can fix light source 10 and binary channels detector 30 simultaneously through an element, and then reduced the quantity of element, and also reduced the installation complexity, be convenient for install and dismantle.
In this embodiment, as shown in fig. 2, the axis of the light source mounting hole 62 and the axis of the detector mounting hole 64 are symmetrically arranged about the axis of the mounting barrel 50, so that the light focused by the concave mirror 40 can vertically enter the dual-channel detector 30, thereby improving the utilization rate of light energy.
Further, as shown in fig. 2, 5 and 6, the mounting groove 522 is a step groove, the step groove includes a first groove 521 and a second groove 523 which are nested, the first groove 521 is nested at the bottom of the second groove 523, and the avoiding hole 524 is located at the bottom of the first groove 521. The mounting base 60 includes a fixing portion 61 and a connecting portion 63, the light source mounting hole 62 and the detector mounting hole 64 are formed in the fixing portion 61, the fixing portion 61 is accommodated in the first groove 521, and the connecting portion 63 is fixedly connected with the bottom surface of the second groove 523. By arranging the mounting groove 522 as a step groove, on one hand, the mounting seat 60 is convenient to limit, and the mounting seat 60 is prevented from moving; on the other hand, the axial length of the mounting seat 60 and the mounting cylinder 50 can be shortened, so that the structure is more compact and the volume is smaller.
In this embodiment, as shown in fig. 2 and 8, fig. 8 is a partially enlarged schematic structural view in fig. 2. The isolation mirror 80 is located in the mounting groove 522, the bottom surface of the first groove 521 is provided with a lens mounting groove 82, the isolation mirror 80 is located in the lens mounting groove 82, and the fixing portion 61 is abutted against the isolation mirror 80. Through setting up the lens mounting groove 82 that is used for holding isolation mirror 80, can inject the removal of isolation mirror 80, only need utilize fixed part 61 butt in the terminal surface of exposing in lens mounting groove 82 of isolation mirror 80, can accomplish the fixed of isolation mirror 80, and then simplify the fixed knot of isolation mirror 80 constructs for the installation is dismantled more conveniently.
Alternatively, as shown in fig. 8, the gas concentration detecting apparatus 100 having two channels further includes an elastic member 90, and the elastic member 90 is elastically sandwiched between the fixing portion 61 and the separation mirror 80. By providing the elastic member 90 between the contact surfaces of the separation mirror 80 and the fixing portion 61, the fixing portion 61 can be prevented from being in hard contact with the separation mirror 80 to damage the separation mirror 80.
Wherein in the present embodiment, the elastic member 90 is provided as an elastic washer. Since the elastic washer is a common standard component, the elastic member 90 is configured as an elastic washer, which can reduce the production cost and also facilitate the replacement of the elastic washer when the elastic washer is damaged. In addition, the annular gasket may also avoid obscuring the relief aperture 524. The material used for manufacturing the elastic member 90 may be plastic, silicone, etc., and the embodiment of the present invention is not limited in particular.
In another embodiment, a spacer 80 is positioned in the detection chamber 55 and adhesively attached to the mounting cylinder 50. Specifically, the isolation mirror 80 is disposed on the surface of the detection chamber 55 where the avoidance hole 524 is formed, so as to seal the detection chamber 55. In the present embodiment, the separator 80 may be bonded to the mounting cylinder 50 with an adhesive. Of course, fastener connection and the like may be employed, and embodiments of the present invention are not particularly limited.
In this embodiment, the light source is a mid-infrared light source emitting light in a wavelength band between 3000 nm and 7000 nm, and the light in this wavelength band is more easily absorbed by the gas to be detected, for example, the absorption intensity of methane to light with a wavelength of 3310nm is 200 times that of light with a wavelength of 1670nm, so that the detection accuracy of the gas concentration detection device with multiple channels is improved. The center wavelength of the first wavelength light may be set to 3200nm to 3400nm, and the light of this wavelength band is more easily absorbed by methane, for example, the absorption intensity of methane to light of wavelength 3310nm is 200 times that of light of wavelength 1670nm, thereby improving the detection accuracy of the dual-channel detector 30. The center wavelength of the first wavelength light may be set to 4200nm to 4300nm, and the light of this wavelength band is more easily absorbed by carbon dioxide. The center wavelength of the first wavelength light may be set to 4600nm to 4700nm, and light in this wavelength band is more easily absorbed by carbon monoxide. The center wavelength of the second wavelength light may be set to 3930nm to 3950nm, and light of this wavelength band is not easily absorbed by the gas.
The invention also provides an alarm device, which comprises an alarm and a gas concentration detection device with two channels, wherein the alarm is electrically connected with the gas concentration detection device with two channels and is used for giving out an alarm sound when the gas concentration detection device with two channels detects that the concentration of the combustible gas is greater than a preset value.
In this embodiment, the structure of the gas concentration detection apparatus with two channels is the same as the structure of the gas concentration detection apparatus 100 with two channels in the above embodiment, please refer to the description in the above embodiment, and the description is omitted here. The preset value of the concentration of the combustible gas can be set according to the explosion-proof requirement, and the embodiment of the invention is not particularly limited.
Referring to fig. 1 and 2, fig. 1 is a schematic perspective view of a gas concentration detecting device with two channels according to an embodiment of the invention, and fig. 2 is a schematic cross-sectional view of the gas concentration detecting device with two channels according to the embodiment of the invention. The gas concentration detection apparatus 100 with two channels includes a light source 10, a concave mirror 40, and a two-channel detector 30, wherein light emitted from the light source 10 irradiates the concave mirror 40, the concave mirror 40 converges and reflects the light to the two-channel detector 30, a distance between the two-channel detector 30 and the concave mirror 40 is equal to a radius of curvature of the concave mirror 40, the two-channel detector 30 includes a detection channel for detecting a first light intensity of a first wavelength light absorbed by a gas and a reference channel for detecting a second light intensity of a second wavelength light not absorbed by the gas, and a concentration of the gas is obtained through the first light intensity and the second light intensity.
In this embodiment, under the same light and gas action distance, the change of the light intensity differential signal of the dual-channel detector 30 increases with the increase of the gas concentration, so that a mathematical relationship curve of one-to-one correspondence between the gas concentration and the light intensity differential signal of the detector is established, and the gas concentration sensing measurement is realized, thus forming the dual-channel detector 30. Meanwhile, the integrated dual-channel detector 30 is adopted to detect the first wavelength light and the second wavelength light simultaneously, so that the first wavelength light and the second wavelength light have the same source and propagation path, and the light intensity disturbance and the light loss caused by the external environment, reflection scattering and the like are the same, therefore, the light intensity dynamic disturbance caused by the light source intensity fluctuation and the propagation loss can be effectively eliminated by utilizing the differential signal processing of the two, and the detection precision of the dual-channel gas concentration detection device 100 is further improved.
In the embodiment of the invention, the distance between the concave reflector 40 and the dual-channel detector 30 is equal to the curvature radius of the concave reflector 40, namely, the dual-channel detector 30 is arranged at the curvature center position of the concave reflector 40, so that the focused focal point of the concave reflector 40 can be ensured to be positioned on the dual-channel detector 30, the incident light intensity of the dual-channel detector 30 is further improved, the detection sensitivity of the dual-channel detector 30 is improved, and the detection precision of the dual-channel gas concentration detection device 100 is further improved.
In this embodiment, the path length of the light from the light source 10 to the incident dual-channel detector 30 is 6-20 cm. For example, the path length may be set to 6cm, 7cm, 8cm, 9cm, 10cm, 11cm, 12cm, 13cm, 14cm, 15cm, 16cm, 17cm, 18cm, 19cm, or 20cm, etc., and may be flexibly set according to the kind of the gas to be measured, and the embodiment of the present invention is not particularly limited.
Further, as shown in fig. 2, the gas concentration detection apparatus 100 having two channels further includes a mounting cylinder 50, the mounting cylinder 50 having opposite first and second ends 51, 53. The mounting barrel 50 is hollow, the light source 10 and the dual channel detector 30 are disposed at a first end 51 of the mounting barrel 50, and the concave mirror 40 is disposed at a second end 53 of the mounting barrel 50. By providing the mounting cylinder 50, the light source 10, the concave mirror 40, and the dual-channel detector 30 can be integrated, facilitating installation.
As shown in fig. 2 and 9, fig. 9 is a schematic perspective view of the mounting cylinder in fig. 2. The second end 53 of the mounting cylinder 50 is provided with a reflector mounting hole 56, the concave reflector 40 is arranged in the reflector mounting hole 56, the aperture of the reflector mounting hole 56 is larger than the inner diameter of the mounting cylinder 50, and the axis of the reflector mounting hole 56 coincides with the axis of the mounting cylinder 50. By providing the mirror mounting hole 56 at the second end 53 of the mounting tube 50 and disposing the concave mirror 40 in the mirror mounting hole 56, the concave mirror 40 can be protected, and the axial length of the gas concentration detection apparatus 100 having two channels can be shortened, thereby reducing the volume of the gas concentration detection apparatus 100 having two channels.
In another embodiment, the concave mirror 40 may be directly disposed on the end surface of the second end 53 of the mounting cylinder 50, or may be disposed at a distance from the end surface of the second end 53 of the mounting cylinder 50, which is not particularly limited in the embodiment of the present invention.
Further, as shown in fig. 2 and 5, ventilation holes 57 are provided in opposite side walls of the mounting cylinder 50. The gas concentration detection device 100 with two channels further comprises a calibration cover 110, wherein the calibration cover 110 is sleeved on the outer side of the mounting cylinder 50 and is connected with the first end 51 of the mounting cylinder 50 to form a detection cavity 55, the detection cavity 55 is communicated with the inside of the mounting cylinder 50, and the calibration cover 110 is provided with an air inlet hole 112 and an air outlet hole 114.
Specifically, in this embodiment, the calibration cap 110 is cylindrical, an opening is disposed on one end surface of the calibration cap 110, the calibration cap 110 is covered on the outer side of the mounting cylinder 50, and the surface of the calibration cap 110 with the opening is connected to the first end 51 of the mounting cylinder 50, so as to seal and form the detection cavity 55. The detection cavity 55 is provided with an air inlet 112 and an air outlet 114, and the gas to be detected enters the detection cavity 55 from the air inlet 112 and flows out from the air outlet 114.
The air inlet 112 is located on a side wall of the calibration cover 110, and the air outlet 114 is located on an end surface of the calibration cover 110 away from the first end 51 of the mounting cylinder 50 within a projection range of the air vent 57 on the side wall. By arranging the air inlet 112 in the projection range of the air vent 57 on the side wall, the content of the air to be detected in the air vent 57 can be increased, and the detection accuracy of the air to be detected can be improved.
Optionally, as shown in fig. 2, the air inlet 112 is disposed on a side of the calibration cover 110 close to the light source 10, so as to prolong the flow path of the gas to be measured, increase the gas content of the gas to be measured in the detection chamber 55, and reduce the influence of air on the concentration of the gas to be measured.
Further, as shown in fig. 2 and 6, the gas concentration detecting apparatus 100 with two channels further includes a mounting base 60, a light source mounting hole 62 and a detector mounting hole 64 are formed on the mounting base 60, the light source 10 is assembled in the light source mounting hole 62, and the two-channel detector 30 is assembled in the detector mounting hole 64. By providing the mounting cylinder 50, the light source 10, the concave mirror 40, and the dual-channel detector 30 can be integrated, facilitating installation.
Alternatively, as shown in fig. 2, in the present embodiment, the axis of the light source mounting hole 62 and the axis of the detector mounting hole 64 are symmetrically disposed about the axis of the mounting barrel 50, so that the light focused by the concave mirror 40 can vertically enter the dual-channel detector 30, thereby improving the utilization rate of light energy.
In this embodiment, the light source is a mid-infrared light source emitting light in a wavelength band between 3000 nm and 7000 nm, and the light in this wavelength band is more easily absorbed by the gas to be detected, for example, the absorption intensity of methane to light with a wavelength of 3310nm is 200 times that of light with a wavelength of 1670nm, so that the detection accuracy of the gas concentration detection device with multiple channels is improved. The center wavelength of the first wavelength light may be set to 3200nm to 3400nm, and the light of this wavelength band is more easily absorbed by methane, for example, the absorption intensity of methane to light of wavelength 3310nm is 200 times that of light of wavelength 1670nm, thereby improving the detection accuracy of the dual-channel detector 30. The center wavelength of the first wavelength light may be set to 4200nm to 4300nm, and the light of this wavelength band is more easily absorbed by carbon dioxide. The center wavelength of the first wavelength light may be set to 4600nm to 4700nm, and light in this wavelength band is more easily absorbed by carbon monoxide. The center wavelength of the second wavelength light may be set to 3930nm to 3950nm, and light of this wavelength band is not easily absorbed by the gas.
The invention also provides an alarm device, which comprises an alarm and a gas concentration detection device with two channels, wherein the alarm is electrically connected with the gas concentration detection device with two channels and is used for giving out an alarm sound when the gas concentration detection device with two channels detects that the concentration of the combustible gas is greater than a preset value.
In this embodiment, the structure of the gas concentration detection apparatus with two channels is the same as the structure of the gas concentration detection apparatus 100 with two channels in the above embodiment, please refer to the description in the above embodiment, and the description is omitted here. The preset value of the concentration of the combustible gas can be set according to the explosion-proof requirement, and the embodiment of the invention is not particularly limited.
Referring to fig. 1 and 2, fig. 1 is a schematic perspective view of a gas concentration detecting device with two channels according to an embodiment of the invention, and fig. 2 is a schematic cross-sectional view of the gas concentration detecting device with two channels according to the embodiment of the invention. The gas concentration detection device 100 with two channels comprises a light source 10, an adaptive light reflecting member 20 and a two-channel detector 30, wherein the light source 10 is arranged in the adaptive light reflecting member 20, light rays emitted by the light source 10 are focused by the adaptive light reflecting member 20 and then irradiate the two-channel detector 30, the two-channel detector 30 comprises a detection channel and a reference channel which are positioned on the same horizontal plane, the detection channel is used for detecting first light intensity of first wavelength light absorbed by gas, the reference channel is used for detecting second light intensity of second wavelength light which is not absorbed by gas, and the concentration of the gas is obtained through the first light intensity and the second light intensity. The detection channel and the reference channel are positioned on the same horizontal plane, so that incident light entering the detection channel and the reference channel can enter simultaneously, further compensation errors are reduced, and the detection precision of the gas concentration detection device 100 with two channels is improved.
According to the embodiment of the invention, the light source 10 is arranged in the self-adaptive light reflecting piece 20, and the self-adaptive light reflecting piece 20 is utilized to collimate the light emitted by the light source 10, so that the light intensity of the light emitted by the light source 10 is improved, the light loss in the light transmission process is reduced, the light intensity incident to the dual-channel detector 30 is further improved, the detection sensitivity and the detection precision of the dual-channel detector 30 are further improved, and the detection precision of the dual-channel gas concentration detection device 100 is further improved.
In this embodiment, the dual-channel detector 30 may be a pyroelectric flammable gas detector, and includes a photoresistor and a circuit board electrically connected to the photoresistor, where the photoresistor changes resistance under the irradiation of light, so as to change the magnitude of current flowing through the photoresistor, and the circuit board receives the magnitude of current and converts the current into a periodic electrical signal, and after the electrical signal is amplified and conditioned by the circuit, the electrical signal is converted into a digital signal by an a/D converter.
Specifically, the two paths of detection channels convert detected light intensity into electric signals, differential processing is carried out on the signals of the two paths of detection channels, light intensity disturbance interference caused by light source power fluctuation and propagation loss is eliminated, and detected light intensity differential change under the action of gas absorption is obtained. Under the same light and gas action distance, the change of the light intensity differential signal of the dual-channel detector 30 is increased along with the increase of the gas concentration, so that a mathematical relationship curve of one-to-one correspondence between the gas concentration and the light intensity differential signal of the dual-channel detector 30 is established, the gas concentration sensing measurement is realized, and the dual-channel detector 30 is formed.
Of course, in other embodiments, other types of dual channel detectors 30 may be used as desired, and embodiments of the present invention are not particularly limited.
As shown in fig. 2 and 3, fig. 3 is a schematic perspective view of the adaptive reflector in fig. 2. In this embodiment, the surface of the adaptive reflector 20 is provided with a reflective groove 22, the sidewall of the reflective groove 22 forms a reflective surface 221, and the light source 10 is installed in the center of the reflective groove 22.
Specifically, in the present embodiment, the reflective cavity 22 is a groove with an opening, and the light emitted from the light source 10 is emitted through the opening. The groove is horn-shaped and is used for converging and then emitting light.
Fig. 4 is a schematic process flow of the adaptive reflector according to an embodiment of the invention, as shown in fig. 4. The adaptive reflector 20 may be manufactured by the following manufacturing steps:
s101: the filament shape dimensions of the plurality of light sources 10 are counted.
S102: modeling is performed with the filament shape dimensions of the light source 10 to obtain an optimal shape curve for the reflective surface 221.
S103: the reflection groove 22 is processed on the adaptive reflection member 20 by using an optimal shape curve of the reflection surface 221, the sidewall of the reflection groove 22 is polished, and an oxidation-preventing protective film 24 is coated on the sidewall of the polished reflection groove 22.
In this embodiment, the anti-oxidation protective film 24 may be an aluminum reflective film, however, in other embodiments, other types of anti-oxidation protective films 24 may be electroplated or coated as needed, for example: 50-200 nm gold film, 50-200 nm silver film, 100-200 nm titanium dioxide film, 100-200 nm vanadium pentoxide film, 100-200 nm silicon dioxide film, 100-200 nm magnesium fluoride film, 100-200 nm silicon nitride film, these types of films not only prevent oxidation but also have high reflectivity. The anti-oxidation protective film 24 coated on the sidewall of the reflective trough 22 can prevent the sidewall of the reflective trough 22 from being oxidized, thereby improving the reflectivity of the reflective surface 221 and reducing the optical loss.
Further, referring to fig. 2 and 3, the adaptive light reflecting member 20 includes a light source portion 21 and a light reflecting portion 23 connected to the light source portion 21, the light source portion 21 is provided with an assembly hole 212, the light reflecting portion 23 is provided with a light reflecting groove 22, and the light source 10 is mounted in the assembly hole 212 and extends into the light reflecting groove 22.
Specifically, in the present embodiment, the light reflecting portion 23 is provided with the light reflecting groove 22, the fitting hole 212 extends from the center position of the light reflecting groove 22 through the light source portion 21, and the light source 10 is mounted in the fitting hole 212 and extends into the light reflecting groove 22. By providing the fitting hole 212 for fitting the light source 10 on the adaptive light reflecting member 20, the light source 10 can be easily fixed, so that the internal structure of the gas concentration detection apparatus 100 having two channels is more compact, and the volume of the gas concentration detection apparatus 100 having two channels can also be reduced. In addition, the structure of the adaptive reflector 20 is also convenient for the fixed connection, so as to facilitate the installation of the adaptive reflector 20.
In another embodiment, the adaptive reflector 20 is configured as a reflector with the light source 10 mounted in the center of the reflector. Because the reflector is convenient to process, the processing cost of the gas concentration detection apparatus 100 with two channels can be reduced.
Optionally, the light reflected and emitted by the adaptive light reflecting member 20 may be set to be parallel light, so as to reduce the diffusion of the light, avoid the light contacting the obstacle during the transmission process, and make a larger proportion of the light incident on the dual-channel detector 30, thereby improving the light energy utilization rate of the light source 10.
In this embodiment, the opening angle of the light reflected by the adaptive reflector 20 is set to be smaller than 15 °. The opening angle of the light ray refers to: the direction of the light emitted by the light reflection forms the maximum included angle with the light emitting direction of the light source 10. By setting the opening angle of the light to be smaller than 15 °, the processing precision of the reflective surface 221 can be reduced while satisfying the higher light energy utilization rate, and further the processing cost can be reduced.
Further, in the present embodiment, as shown in fig. 3, the light reflecting surface 221 of the adaptive light reflecting member 20 is a smooth curved surface, so as to reduce the processing difficulty. Of course, in other embodiments, the light reflecting surface 221 may be formed by splicing a plurality of flat surfaces. For example, a plurality of triangular planes may be sequentially connected to form the display device. Or a plurality of hexagonal planes are adopted to be spliced in sequence. Or by splicing other polygonal planes, and the embodiment of the invention is not particularly limited.
Further, as shown in fig. 2 and 5, the gas concentration detection apparatus 100 having two channels further includes a concave mirror 40 and a mounting cylinder 50, the mounting cylinder 50 having opposite first and second ends 51 and 53. The light source 10 and the dual channel detector 30 are disposed at a first end 51 of the mounting barrel 50 and the concave mirror 40 is disposed at a second end 53 of the mounting barrel 50. The light emitted from the light source 10 is reflected by the concave mirror 40 and then irradiated to the dual-channel detector 30. By arranging the concave reflecting mirror 40, the present embodiment can focus the outgoing light of the light source 10 to increase the light intensity, and can shorten the distance between the light source 10 and the dual-channel detector 30 under the condition of ensuring a certain optical path, so that the structure is more compact, and the volume of the dual-channel gas concentration detection device 100 is further reduced. In this embodiment, the concave mirror 40 is formed by glass processing, mirror polishing, and finally gold plating. In this embodiment, by providing the concave reflecting mirror 40, light energy can be converged on the dual-channel detector 30, so as to make up for the defect of small photosensitive surface and low sensitivity of the dual-channel detector 30.
In this embodiment, the light source is a mid-infrared light source emitting light in a wavelength band between 3000 nm and 7000 nm, and the light in this wavelength band is more easily absorbed by the gas to be detected, for example, the absorption intensity of methane to light with a wavelength of 3310nm is 200 times that of light with a wavelength of 1670nm, so that the detection accuracy of the gas concentration detection device with multiple channels is improved. The center wavelength of the first wavelength light may be set to 3200nm to 3400nm, and the light of this wavelength band is more easily absorbed by methane, for example, the absorption intensity of methane to light of wavelength 3310nm is 200 times that of light of wavelength 1670nm, thereby improving the detection accuracy of the dual-channel detector 30. The center wavelength of the first wavelength light may be set to 4200nm to 4300nm, and the light of this wavelength band is more easily absorbed by carbon dioxide. The center wavelength of the first wavelength light may be set to 4600nm to 4700nm, and light in this wavelength band is more easily absorbed by carbon monoxide. The center wavelength of the second wavelength light may be set to 3930nm to 3950nm, and light of this wavelength band is not easily absorbed by the gas.
The invention also provides an alarm device, which comprises an alarm and a gas concentration detection device with two channels, wherein the alarm is electrically connected with the gas concentration detection device with two channels and is used for giving out an alarm sound when the gas concentration detection device with two channels detects that the concentration of the combustible gas is greater than a preset value.
The foregoing is only the embodiments of the present invention, and therefore, the patent scope of the invention is not limited thereto, and all equivalent structures or equivalent processes using the descriptions of the present invention and the accompanying drawings, or direct or indirect application in other related technical fields, are included in the scope of the invention.

Claims (7)

1. A gas concentration detection device with two channels is characterized in that the gas concentration detection device with two channels comprises a light source, a concave reflector and a two-channel detector,
the light emitted by the light source irradiates the concave reflecting mirror, the concave reflecting mirror converges and reflects the light to the double-channel detector, the double-channel detector comprises a detection channel and a reference channel which are positioned on the same horizontal plane, the detection channel is used for detecting first light intensity of first wavelength light absorbed by gas, the reference channel is used for detecting second light intensity of second wavelength light which is not absorbed by gas, and the concentration of the gas is obtained through the first light intensity and the second light intensity;
The gas concentration detection device with the double channels further comprises a mounting cylinder and a mounting seat, wherein the mounting cylinder is provided with a first end, the mounting seat is connected to the first end of the mounting cylinder, and the light source and the double-channel detector are arranged on the mounting seat;
the mounting seat is provided with a light source mounting hole and a detector mounting hole, the light source is assembled in the light source mounting hole, the dual-channel detector is assembled in the detector mounting hole, and the axis of the light source mounting hole and the axis of the detector mounting hole are inclined relative to the axis of the mounting cylinder and are symmetrically arranged relative to the axis of the mounting cylinder;
the gas concentration detection device with the double channels further comprises an adaptive light reflecting piece, the light source is arranged in the adaptive light reflecting piece, and light rays reflected and emitted by the adaptive light reflecting piece are parallel light; or the opening angle of the light rays reflected and emitted by the self-adaptive reflecting piece is smaller than 15 degrees;
a detection cavity is formed in the mounting cylinder, a mounting groove for accommodating the mounting seat is formed in the mounting cylinder, and an avoidance hole for communicating the detection cavity with the mounting groove is formed in the bottom of the mounting groove; an isolation mirror for covering the avoidance hole to isolate the detection cavity from the mounting groove is arranged between the bottom wall of the mounting groove and the mounting seat, the mounting seat comprises a fixing part, and the fixing part is abutted to the isolation mirror; the gas concentration detection device with the double channels further comprises an elastic piece, and the elastic piece is clamped between the fixing part and the isolation mirror.
2. The dual-channel gas concentration detection apparatus according to claim 1, wherein the dual-channel gas concentration detection apparatus includes a first narrowband filter provided in the detection channel and a second narrowband filter provided in the reference channel;
the light entering the detection channel is filtered by the first narrow-band filter to obtain the first wavelength light, the light entering the reference channel is filtered by the second narrow-band filter to obtain the second wavelength light, the first wavelength light can be absorbed by gas, and the second wavelength light cannot be absorbed by gas.
3. The apparatus for detecting a gas concentration having two channels according to claim 1, wherein,
the mounting cylinder is provided with a second end which is opposite to the first end, and the concave reflector is arranged at the second end of the mounting cylinder.
4. The gas concentration detection apparatus with two channels according to claim 3, wherein the mounting cylinder comprises a mounting part and a cylinder body, the cylinder body is arranged in a hollow manner and is connected to one side of the mounting part, the mounting groove is formed in the surface of the mounting part far away from the cylinder body, and the concave reflector is arranged on one side of the cylinder body far away from the mounting part; light rays emitted by the light source are incident to the concave reflecting mirror through the avoidance hole, and reflected light of the concave reflecting mirror is incident to the double-channel detector through the avoidance hole.
5. A detection method, characterized in that the gas concentration detection is performed by using the gas concentration detection apparatus having a double channel according to any one of claims 1 to 4; the detection method comprises the following steps: controlling the light source to periodically emit light;
controlling a concave reflector to focus and reflect emergent light of the light source to a dual-channel detector, wherein the dual-channel detector comprises a detection channel and a reference channel, the detection channel is used for detecting first light intensity of first wavelength light absorbed by gas, and the reference channel is used for detecting second light intensity of second wavelength light not absorbed by gas;
and responding to the corresponding relation between the ratio of the first light intensity to the second light intensity and the concentration of the gas to be detected, and obtaining the concentration of the gas to be detected.
6. The method according to claim 5, wherein the light source emits light at a frequency of 1 to 10HZ.
7. An alarm device, characterized in that the alarm device comprises an alarm and a gas concentration detection device with two channels according to any one of claims 1-4, the alarm is electrically connected with the gas concentration detection device with two channels, and is used for giving out an alarm sound when the gas concentration detection device with two channels detects that the concentration of combustible gas is larger than a preset value.
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