CN111707623B - Gas concentration detection device and detection method - Google Patents
Gas concentration detection device and detection method Download PDFInfo
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- CN111707623B CN111707623B CN202010523673.0A CN202010523673A CN111707623B CN 111707623 B CN111707623 B CN 111707623B CN 202010523673 A CN202010523673 A CN 202010523673A CN 111707623 B CN111707623 B CN 111707623B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
Abstract
The present application relates to a gas concentration detection apparatus and a detection method. The gas concentration detection apparatus includes: light source module, test module and detection module. The test module comprises a reference unit, a measuring unit, a conductive optical fiber and a light splitting unit. The beam splitting unit is used for receiving and splitting the detection beam into three beams with the same energy. One of the three light beams passes through the conducting optical fiber to output an original light signal, the other of the three light beams passes through the first detecting optical fiber of the reference unit to output a reference light signal, and the rest of the three light beams passes through the second detecting optical fiber of the measuring unit to output a measuring light signal. The detection module is used for receiving the original optical signal, the reference optical signal and the measurement optical signal, filtering the measurement optical signal according to the reference optical signal, and obtaining the concentration of the gas to be detected according to the ratio of the energy of the filtered measurement optical signal to the energy of the original optical signal. The application can accurately measure the gas to be measured.
Description
Technical Field
The application relates to the technical field of gas detection, in particular to a gas concentration detection device and a detection method.
Background
Conventionally, gas detection techniques can be classified into chemical detection methods, gas chromatography, and spectroscopy, depending on the detection mechanism.
The chemical detection method is to induce the components of the gas to be detected through physical and chemical reaction, convert the components into corresponding electric signals, and determine the concentration of the gas to be detected through detection and processing of the signals. Gas chromatography is one type of chromatography. There are two phases in chromatography. One phase is the mobile phase and the other phase is the stationary phase. If a liquid is used as the mobile phase, it is called liquid chromatography, and if a gas is used as the mobile phase, it is called gas chromatography.
The chemical detection method and the gas chromatography have limited detection precision, and the concentration of the gas to be detected is difficult to be accurately measured.
Disclosure of Invention
In view of the above, it is desirable to provide a gas concentration detection apparatus and a gas concentration detection method capable of accurately measuring a gas to be measured.
A gas concentration detection apparatus comprising:
a light source module for providing a detection beam;
the test module comprises a reference unit, a measuring unit, a base unit and a light splitting unit; the reference unit comprises a first detection optical fiber, the first detection optical fiber comprises a first fiber core and a first cladding wrapping the first fiber core, the first detection optical fiber is used for being exposed to reference gas, and no gas to be detected is introduced into the reference gas; the measuring unit comprises a second detecting optical fiber with equal length as the first detecting optical fiber, the second detecting optical fiber comprises a second fiber core and a second cladding wrapping the second fiber core, and the second detecting optical fiber is used for being exposed to gas to be measured; the base unit comprises a conductive optical fiber, the conductive optical fiber comprises a conductive fiber core, a conductive cladding, and a shielding layer, the conductive cladding wraps the conductive fiber core, and the shielding layer wraps the conductive cladding; the light splitting unit is used for receiving and splitting the detection light beams into three light beams with the same energy, one of the three light beams passes through the conducting optical fiber to output an original light signal, the other of the three light beams passes through the first detection optical fiber to output a reference light signal, and the rest of the three light beams pass through the second detection optical fiber to output a measurement light signal;
the detection module is used for receiving the original optical signal, the reference optical signal and the measurement optical signal, obtaining a noise interference signal according to the reference optical signal, filtering the measurement optical signal according to the noise interference signal, and obtaining the concentration of the gas to be detected according to the ratio of the energy of the filtered measurement optical signal to the energy of the original optical signal.
In one embodiment, the reference unit further comprises a first air chamber, the first detection fiber being disposed within the first air chamber; the measuring unit further comprises a second air chamber, the second air chamber is used for introducing gas to be measured, and the second detection optical fiber is arranged in the second air chamber.
In one embodiment, the light source module includes:
a broadband light source for outputting a broadband light beam;
and the filtering unit is used for filtering the broadband light beam and sending out a detection light beam with a preset bandwidth.
In one embodiment, the filtering unit includes a driving part and a plurality of filters, and the driving part is used for driving the plurality of filters to switch.
In one of the embodiments of the present application,
the test module further comprises a fan unit for passing the tested gas into the second air chamber.
In one of the embodiments of the present application,
the reference unit further comprises a first winding, and the first detection optical fiber is wound on the first winding along the circumferential direction of the first winding;
and/or the measuring unit further comprises a second winding, and the second detection optical fiber is wound on the second winding along the circumferential direction of the second winding.
In one embodiment, the gas concentration detection device further comprises a display module, and the display module is connected with the detection module and is used for displaying a detection result.
A gas concentration detection method based on the gas concentration detection device comprises the following steps:
providing a detection beam;
dividing the detection light beam into three light beams with the same energy, wherein one of the three light beams passes through the conducting optical fiber to output an original light signal, the other of the three light beams passes through the first detection optical fiber to output a reference light signal, and the rest of the three light beams passes through the second detection optical fiber to output a measurement light signal;
obtaining a noise interference signal according to the reference light signal;
filtering the measurement light signal according to the noise interference signal;
and obtaining the concentration of the gas to be detected according to the ratio of the energy of the filtered measurement light signal to the energy of the original light signal.
In one embodiment, the providing the detection beam includes:
outputting a broadband light beam;
filtering the broadband light beam to emit a detection light beam with a preset bandwidth.
In one embodiment, before the other of the three light beams passes through the first detection optical fiber to output a reference light signal, the method further comprises:
the first detection fiber is exposed to a vacuum.
According to the gas concentration detection device and the gas concentration detection method, the noise interference signal in the measurement optical signal is effectively filtered through the reference optical signal, and then the concentration of the gas to be detected is obtained through the ratio of the energy of the filtered measurement optical signal to the energy of the original optical signal, so that the detection precision of the concentration of the gas to be detected is greatly improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present application, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.
FIG. 1 is a block diagram showing a structure of a gas concentration detecting apparatus in one embodiment;
FIG. 2 is a block diagram of a test module in one embodiment;
FIG. 3 is a schematic diagram illustrating an assembly of a first detection light and a first winding according to an embodiment;
FIG. 4 is a block diagram of a test module in one embodiment;
FIG. 5 is a block diagram of the detection module in one embodiment;
FIG. 6 is a block diagram of a display module in one embodiment;
FIG. 7 is a flow chart of a method for detecting gas concentration in one embodiment;
FIG. 8 is a flow chart of providing a detection beam in one embodiment.
Reference numerals illustrate: 100-light source module, 110-broadband light source, 120-filter unit, 121-driving part, 122-filter, 200-test module, 210-spectroscopic unit, 220-reference unit, 221-first detection fiber, 222-first winding, 230-measurement unit, 240-fan unit, 300-detection module, 310-photoelectric conversion unit, 320-first processing unit, 400-display module, 410-second processing unit, 420-display unit, 500-power module
Detailed Description
In order that the application may be readily understood, a more complete description of the application will be rendered by reference to the appended drawings. Embodiments of the application are illustrated in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that the terms first, second, etc. as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected to the other element through intervening elements. Further, "connection" in the following embodiments should be understood as "connection", "communication connection", and the like if there is transmission of electrical signals or data between objects to be connected.
As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, the term "and/or" as used in this specification includes any and all combinations of the associated listed items.
In one embodiment, referring to fig. 1, a gas concentration detection apparatus is provided that includes a light source module 100, a test module 200, and a detection module 300.
The light source module 100 is used for providing a detection beam. The "detection beam" herein is a beam having a preset bandwidth that can be used for gas concentration detection. Each gas molecule has its own absorption (or radiation) spectral characteristics. Only the portion of the spectrum of the detection light beam emitted from the light source module 100 overlapping the absorption spectrum of the gas to be measured is absorbed. After the gas to be detected is subjected to spectral absorption, the output energy of the detection light beam changes, so that the concentration of the gas to be detected can be detected.
Referring to fig. 2, the test module 200 includes a spectroscopic unit 210, a base unit (not shown), a reference unit 220, and a measurement unit 230.
The beam splitting unit 210 is configured to receive and split the detection beam into three beams with the same energy. Specifically, the light splitting unit 210 may include an optical device such as a fiber coupler.
The base unit includes a conductive optical fiber. The conductive optical fiber includes a conductive core, a conductive cladding, and a shielding layer. The conductive cladding surrounds the conductive core. The shielding layer wraps the conductive cladding layer, and then plays a role in electromagnetic shielding.
Referring to fig. 3, the reference unit 220 includes a first detection fiber 221. The first detection fiber 221 includes a first core and a first cladding. The first cladding surrounds the first core. In performing the gas concentration detection, the first detection optical fiber 221 is exposed to the reference gas. The reference gas is not introduced with the gas to be measured, so that the first detection optical fiber 221 can be used as a reference.
The measurement unit 230 includes a second detection fiber. The second detection fiber is equal in length to the first detection fiber 221 and includes a second core and a second cladding. The second cladding layer encapsulates the second core. In the gas concentration detection, the second detection optical fiber is exposed to the gas to be detected.
Specifically, in performing gas concentration detection, the spectroscopic unit 210 receives and splits the detection beam into three beams of equal energy. One of the three beams passes through a conducting fiber to output the original optical signal to the detection module 300. The other two bundles enter the first detection fiber 221 and the second detection fiber, respectively. The first detection optical fiber 221 guides the light beam entering therein and outputs a reference light signal to the detection module 300. The second detection fiber conducts the light beam entering therein and outputs a measurement light signal to the detection module 300.
The detection module 300 receives the raw optical signal, the reference optical signal, and the measurement optical signal.
The conductive optical fiber used in the present application includes a core, a cladding, and a shielding layer, which may be a conventional optical fiber. The first detection fiber 221 and the second detection fiber are composed of only a core and a cladding, and the cladding directly contacts the outside. Specifically, the shielding layer outside the cladding of the conventional optical fiber may be stripped off using an optical fiber tool. The optical fiber has a three-layer waveguide structure consisting of a fiber core, a cladding and external air. Since there are boundaries between materials, there are two interfaces at this time, one being the core and cladding interface and the other being the cladding and ambient gas interface.
For an optical fiber that does not include a shielding layer, when a light beam enters the optical fiber, two refraction phenomena occur in the light, one being refraction between the core and the cladding, and the other being refraction between the cladding and the ambient gas. When the concentration or type of the external gas changes, the transmission and refraction characteristics of the light rays also change. Related studies have shown that the loss of incident light energy is a linear relationship with ambient gas concentration. Thus, on-line monitoring of gas concentration can be achieved by this principle.
The second detection optical fiber is exposed to the gas to be detected. Therefore, the concentration of the gas to be measured can be detected by the measuring light signal output by the second detecting optical fiber.
Meanwhile, the inventor found that since the second detection optical fiber has no shielding layer, the light transmitted through the second detection optical fiber is interfered by electromagnetic signals in the surrounding environment. Therefore, the measurement light signal output by the second detection optical fiber is doped with a noise interference signal, so that the detection precision of the concentration of the gas to be detected is affected.
In an embodiment of the present application, the test module 200 further includes a reference unit 220. The first detection optical fiber 221 and the second detection optical fiber in the reference unit 220 have the same length, and thus are subjected to the same noise interference signal in the environment.
Meanwhile, in the concentration detection, the first detection fiber 221 of the reference unit 220 is exposed to the reference gas into which the gas to be detected is not introduced, so that the transmission of light in the first detection fiber 221 is not affected by the gas to be detected. Accordingly, the detection module 300 may obtain a noise interference signal from the reference light signal. Specifically, the detection module 300 may further obtain the frequency of the noise interference signal by performing an evaluation rate analysis on the reference optical signal output by the first detection optical fiber 221.
After obtaining the noise interference signal, the measurement light signal may be filtered according to the noise interference signal. At this time, the detection module 300 may first suppress the noise interference signal in the measurement optical signal, and then filter the measurement optical signal. Then, the detection module 300 obtains the concentration of the gas to be detected according to the ratio of the energy of the filtered measurement light signal to the energy of the original light signal.
In this embodiment, the noise interference signal in the measurement optical signal can be effectively filtered out by the reference optical signal emitted in the reference unit, so that the concentration detection precision of the gas to be detected is greatly improved.
In one embodiment, referring to fig. 4, the light source module 100 includes a broadband light source 110 and a filtering unit 120. The broadband light source 110 outputs a broadband light beam. The filtering unit 120 is configured to filter the broadband light beam, and further emit a detection light beam with a preset bandwidth. The detection beam of the preset bandwidth at this time may be a narrowband light.
In this embodiment, by combining the broadband light source 110 with the filtering unit 120, the detection light beam with the preset bandwidth is more conveniently obtained, and the acquisition of the narrowband light with low cost is easy to be realized.
Further, the filtering unit 120 may include a driving part 121 and a plurality of filters 122. The driving unit 121 is configured to drive the plurality of filters 122 to switch. At this time, the light source module 100 can poll and output various customizable narrowband lights, so that the gas concentration detection device can more flexibly detect multiple gases at the same time.
The driving part 121 may be a stepping motor or other electronic or mechanical structure that can realize the replacement of the optical filter 122, etc. Of course, the filter unit 120 may not include the driving part 121, and the filter 122 may be manually removed and disposed.
In one embodiment, referring to fig. 3, the reference unit 220 includes a first plenum (not shown) and a first detection fiber 221. The first air chamber is not filled with the air to be measured. The first detection fiber 221 is disposed in the first air chamber. The measurement unit 230 includes a second air cell and a second detection fiber. The second air chamber is used for introducing gas to be tested. The second detection optical fiber is arranged in the second air chamber.
The materials (specifically, glass materials and the like may be selected) and the shapes of the first air chamber and the second air chamber may be the same or different. The first gas chamber may be evacuated to a vacuum chamber prior to the detection of the gas concentration to prevent the gas in the chamber from affecting the accuracy of the measurement.
In this embodiment, the first air chamber and the second air chamber are provided, so that the specific environments exposed by the first detection optical fiber and the second detection optical fiber can be controlled conveniently. Of course, the present application is not limited thereto, and in other embodiments, it may be determined whether to provide the first air chamber and the second air chamber according to the actual situation.
In one embodiment, referring to FIG. 2, the test module 200 further includes a fan unit 240. The fan unit 240 is used for introducing the measured gas into the second air chamber. At this time, the fan unit 240 can simply and effectively guide the measured gas into the second air chamber. Also, the intake air amount of the measured gas can be effectively adjusted by the fan unit 240.
In one embodiment, the second gas chamber has a gas inlet for introducing a gas to be measured into the second gas chamber and a gas outlet for exhausting the gas to be measured from the second gas chamber.
In the present embodiment, the measurement unit 230 further includes at least two dust screens (not shown). At least two dustproof screens are respectively arranged at the air inlet and the air outlet of the second air chamber. The arrangement of the dustproof net can effectively prevent dust, sand and the like from entering the second air chamber, and further effectively prevent the second detection optical fiber arranged in the second air chamber from being damaged.
In the embodiment of the application, in order to improve the detection precision of the gas to be detected, the length of the second detection optical fiber in the second gas chamber into which the gas to be detected is introduced is generally required to be longer than the preset length, so that the light beam transmitted through the second detection optical fiber can pass through a sufficient optical path, and the attenuation of the output measurement light signal is sufficient. The first detection fiber 221 is equal in length to the second detection fiber, and thus, the length thereof is also longer than the predetermined length.
In order to facilitate the provision of a first detection fiber 221 of sufficient length in the first gas chamber, a reference unit 220 may be provided which further comprises a first winding 222. The first winding 222 and the first detection fiber 221 may be disposed together in the first air chamber. As shown in fig. 3, the first detection optical fiber 221 is wound around the first winding 222 along the circumferential direction of the first winding 222.
And/or, in order to facilitate the placement of a sufficient length of the second detection fibers, respectively, in the second air chamber, the measurement unit 230 may be provided further comprising a second winding. The second winding and the second detection fiber may be disposed together in the second air chamber. The second detection optical fiber is wound on the second winding along the circumferential direction of the second winding. The arrangement of the second detection fiber and the second winding may refer to the arrangement of the first detection fiber 221 and the first winding 222 in fig. 3.
Of course, the first detection optical fiber 221 and/or the second detection optical fiber may be provided in other manners, as long as it is ensured to have a sufficient length.
In one embodiment, referring to fig. 1, the gas concentration detection apparatus further includes a display module 400. The display module 400 is connected to the detection module 300, and further displays the detection result.
Specifically, in some embodiments, referring to fig. 5, the detection module 300 may include a photoelectric conversion unit 310 and a first processing unit 320. The photoelectric conversion unit 310 is used for converting the original optical signal, the reference optical signal, and the measurement optical signal into corresponding electrical signals.
The first processing unit 320 receives the electrical signal output from the photoelectric conversion unit 310, and calculates the ratio of the energy of the filtered measurement light signal to the energy of the original light signal according to the ratio, thereby obtaining the energy loss percentage of the filtered measurement light signal. The first processing unit 320 then maps the percent energy loss to the concentration of the gas under test in the first gas chamber. In addition, the first processing unit 320 may also be used to control the light source module 100 (e.g., control a stepper motor to implement filter replacement).
The first processing unit 320 may be a micro processing unit (MCU), which may be connected to the display module 400, so as to interact with the display module 400.
Referring to fig. 5, the display module 400 may include a second processing unit 410 and a display unit 420. The second processing unit 410 may interact with the first processing unit 320 to store the concentration of the gas to be measured detected by the detection module 300.
Meanwhile, when the filter unit 120 includes a plurality of filters 122, the second processing unit 410 may also set a range of concentration normal values of the gas to be measured detected under each filter. Then, the second processing unit 410 may further determine whether the concentration of the gas to be measured is normal or abnormal according to the above.
In addition, when the filter unit 120 includes a plurality of filters 122, the second processing unit 410 may further set that the plurality of filters 122 are smoothly switched, so as to sequentially test the corresponding gas to be tested.
The display unit 420 may be a liquid crystal display, etc., which is connected to the second processing unit 410, so as to display the concentration of the gas to be measured. When the second processing unit 410 determines whether the gas to be measured is normal or abnormal, the display unit 420 may also display the determination result.
In addition, in the embodiment of the present application, the gas concentration detection apparatus may further include a power module 500. The power module 500 may provide power to the light source module 100, the test module 200, the detection module 300, and the display module 400.
In one embodiment, referring to fig. 7, there is provided a gas concentration detection method, based on the above gas concentration detection apparatus, comprising the steps of:
step S1, providing a detection beam.
The "detection beam" herein is a beam having a preset bandwidth that can be used for gas concentration detection.
In step S2, the detection beam is divided into three beams with the same energy, one of the three beams outputs an original optical signal through the transmission optical fiber, the other of the three beams outputs a reference optical signal through the first detection optical fiber 221, and the remaining one of the three beams outputs a measurement optical signal through the second detection optical fiber.
The conductive optical fiber includes a core, a cladding, and a shielding layer, which may be a conventional optical fiber. The first detection fiber 221 and the second detection fiber are composed of only a core and a cladding, and the cladding directly contacts the outside. Specifically, the shielding layer outside the cladding of the conventional optical fiber may be stripped off using an optical fiber tool. The optical fiber has a three-layer waveguide structure consisting of a fiber core, a cladding and external air. Since there are boundaries between materials, there are two interfaces at this time, one being the core and cladding interface and the other being the cladding and ambient gas interface.
For an optical fiber that does not include a shielding layer, when a light beam enters the optical fiber, two refraction phenomena occur in the light, one being refraction between the core and the cladding, and the other being refraction between the cladding and the ambient gas. When the concentration or type of the external gas changes, the transmission and refraction characteristics of the light rays also change. Related studies have shown that the loss of incident light energy is a linear relationship with ambient gas concentration. Thus, on-line monitoring of gas concentration can be achieved by this principle.
The second detection optical fiber is exposed to the gas to be detected. Therefore, the concentration of the gas to be measured can be detected by the measuring light signal output by the second detecting optical fiber.
Meanwhile, the inventor found that since the second detection optical fiber has no shielding layer, the light transmitted through the second detection optical fiber is interfered by electromagnetic signals in the surrounding environment. Therefore, the measurement light signal output by the second detection optical fiber is doped with a noise interference signal, so that the detection precision of the concentration of the gas to be detected is affected.
In an embodiment of the present application, the test module 200 further includes a reference unit 220. The first detection optical fiber 221 and the second detection optical fiber in the reference unit 220 have the same length, and thus are subjected to the same noise interference signal in the environment.
Meanwhile, the reference unit 220 is exposed to the reference gas, which is not introduced with the gas to be measured, so that the transmission of light in the first sensing optical fiber 221 is not affected by the gas to be measured. Thus, the reference light signal may be used to obtain a noise interference signal.
And S3, obtaining a noise interference signal according to the reference light signal.
And S4, filtering the measurement light signal according to the noise interference signal.
After obtaining the noise interference signal, the measurement light signal may be filtered according to the noise interference signal. At this time, the detection module may suppress and compress the noise interference signal in the measurement optical signal, so as to filter the measurement optical signal.
And S5, obtaining the concentration of the gas to be detected according to the ratio of the energy of the filtered measurement light signal to the energy of the original light signal.
In this embodiment, the noise interference signal in the measurement optical signal is effectively filtered through the reference optical signal, and then the concentration of the gas to be measured is obtained through the ratio of the energy of the filtered measurement optical signal to the energy of the original optical signal, so that the detection precision of the concentration of the gas to be measured is greatly improved.
In one embodiment, referring to fig. 8, step S1 of providing a detection beam includes:
step S11, outputting a broadband light beam.
Step S13, filtering the broadband light beam to emit a detection light beam with a preset bandwidth.
Before step S13 (filtering the broadband light beam to emit the detection light beam with the preset bandwidth), the method may further include: step S12, switching the optical filter.
The embodiment can be more convenient for obtaining the detection light beam with the preset bandwidth, and is easy to obtain the low-cost narrow-band light.
In one embodiment, before another of the three light beams passes through the first detection fiber to output the reference light signal, further comprising: the first detection fiber is exposed to vacuum.
At this time, the reference unit may include a first air chamber in which the first detection optical fiber is disposed. Exposing the first detection fiber to vacuum may specifically include evacuating the first gas chamber. At this time, the air in the first air chamber can be effectively removed, so as to prevent the gas component (such as oxygen) in the air from affecting the light transmission in the first detection optical fiber 231, thereby ensuring the accuracy of the detection of the gas to be detected.
It should be understood that, although the steps in the flowcharts of fig. 7 to 8 are shown in order as indicated by the arrows, these steps are not necessarily performed in order as indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least a portion of the steps of fig. 7-8 may include multiple steps or stages that are not necessarily performed at the same time, but may be performed at different times, nor does the order in which the steps or stages are performed necessarily occur sequentially, but may be performed alternately or alternately with other steps or at least a portion of the steps or stages in other steps.
Those skilled in the art will appreciate that implementing all or part of the above-described methods in accordance with the embodiments may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, or the like. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory. By way of illustration, and not limitation, RAM can be in the form of a variety of forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), and the like.
In the description of the present specification, reference to the term "one embodiment" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The foregoing examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (10)
1. A gas concentration detection apparatus, comprising:
a light source module for providing a detection beam;
the test module comprises a reference unit, a measuring unit, a base unit and a light splitting unit; the reference unit comprises a first detection optical fiber, the first detection optical fiber comprises a first fiber core and a first cladding wrapping the first fiber core, the first detection optical fiber is used for being exposed to reference gas, and no gas to be detected is introduced into the reference gas; the measuring unit comprises a second detecting optical fiber with equal length as the first detecting optical fiber, the second detecting optical fiber comprises a second fiber core and a second cladding wrapping the second fiber core, and the second detecting optical fiber is used for being exposed to gas to be measured; the base unit comprises a conductive optical fiber, the conductive optical fiber comprises a conductive fiber core, a conductive cladding, and a shielding layer, the conductive cladding wraps the conductive fiber core, and the shielding layer wraps the conductive cladding; the light splitting unit is used for receiving and splitting the detection light beams into three light beams with the same energy, one of the three light beams passes through the conducting optical fiber to output an original light signal, the other of the three light beams passes through the first detection optical fiber to output a reference light signal, and the rest of the three light beams pass through the second detection optical fiber to output a measurement light signal;
the detection module is used for receiving the original optical signal, the reference optical signal and the measurement optical signal, obtaining a noise interference signal according to the reference optical signal, filtering the measurement optical signal according to the noise interference signal, and obtaining the concentration of the gas to be detected according to the ratio of the energy of the filtered measurement optical signal to the energy of the original optical signal;
the first detection optical fiber and the second detection optical fiber do not comprise shielding layers, light beams enter the optical fibers, refraction occurs between the fiber cores and the cladding layers and between the cladding layers and the outside air, and the loss ratio of the energy of the incident light has a linear relation with the concentration of the outside air.
2. The gas concentration detection apparatus according to claim 1, wherein the reference unit further comprises a first gas chamber, the first detection optical fiber being disposed in the first gas chamber; the measuring unit further comprises a second air chamber, the second air chamber is used for introducing gas to be measured, and the second detection optical fiber is arranged in the second air chamber.
3. The gas concentration detection apparatus according to claim 1 or 2, wherein the light source module includes:
a broadband light source for outputting a broadband light beam;
and the filtering unit is used for filtering the broadband light beam and sending out a detection light beam with a preset bandwidth.
4. A gas concentration detection apparatus according to claim 3, wherein the filter unit includes a driving member for driving the plurality of filters to switch, and a plurality of filters.
5. The gas concentration detection apparatus according to claim 2, wherein,
the test module further comprises a fan unit for passing the tested gas into the second air chamber.
6. The gas concentration detection apparatus according to claim 1 or 2, wherein,
the reference unit further comprises a first winding, and the first detection optical fiber is wound on the first winding along the circumferential direction of the first winding;
and/or the measuring unit further comprises a second winding, and the second detection optical fiber is wound on the second winding along the circumferential direction of the second winding.
7. The gas concentration detection apparatus according to claim 1 or 2, further comprising a display module connected to the detection module for displaying a detection result.
8. A gas concentration detection method, characterized by comprising, based on the gas concentration detection apparatus according to any one of claims 1 to 7:
providing a detection beam;
dividing the detection light beam into three light beams with the same energy, wherein one of the three light beams passes through the conducting optical fiber to output an original light signal, the other of the three light beams passes through the first detection optical fiber to output a reference light signal, and the rest of the three light beams passes through the second detection optical fiber to output a measurement light signal;
obtaining a noise interference signal according to the reference light signal;
filtering the measurement light signal according to the noise interference signal;
and obtaining the concentration of the gas to be detected according to the ratio of the energy of the filtered measurement light signal to the energy of the original light signal.
9. The method of claim 8, wherein providing a detection beam comprises:
outputting a broadband light beam;
filtering the broadband light beam to emit a detection light beam with a preset bandwidth.
10. The gas concentration detection method according to claim 8, further comprising, before another of the three light beams passes through the first detection optical fiber to output a reference light signal:
the first detection fiber is exposed to a vacuum.
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