CN117679010A - Gas concentration detection device - Google Patents

Abstract

The application relates to the technical field of gas concentration detection, the utility model discloses a gas concentration detection device, including the infrared light source, convex lens, the air chamber, infrared detector and data processing unit, the both ends at the air chamber are fixed respectively to infrared light source and infrared detector, convex lens sets up in infrared light source one side, the infrared light that the infrared light source sent is gathered by convex lens, make more infrared light get into the air chamber, thereby the light signal intensity in the air chamber has been strengthened, in addition, still strengthen the scattering degree of infrared light, make the optical path of infrared light in the air chamber increase, infrared light absorptivity has been improved, thereby the intensity of electric signal is improved, the infrared light is partly absorbed by the gas that awaits measuring in the air chamber when passing through the air chamber, output corresponding electric signal after final infrared detector received the optical signal, final data processing unit carries out the calculation of gas concentration according to this electric signal. The device has improved the accuracy that gas concentration detected, has solved the lower problem of current gas concentration detection device accuracy.

Description

Gas concentration detection device

Technical Field

The application relates to the technical field of gas concentration detection, in particular to a gas concentration detection device.

Background

The pulmonary dispersion refers to the process of gas exchange of oxygen and carbon dioxide in the lung through alveoli and pulmonary capillary walls, and in medical clinical detection, a pulmonary dispersion function test is a core detection item of a pulmonary function test, and by allowing a subject to inhale carbon monoxide gas with a certain concentration, the concentration change of the carbon monoxide gas before and after expiration is measured, so as to evaluate the diffusion condition of the gas in a respiratory system. Because carbon monoxide gas can absorb light of specific wavelength, the concentration data of carbon monoxide gas is determined by the current lung dispersion detection device through the light intensity amplitude variation of the detector after the light is detected to be absorbed, but the angle of the light scattered by the used infrared steady-state light source is larger, a plurality of light does not enter the air chamber, so that the effective light signal finally irradiated on the detector is lost to a certain extent, and the gas concentration accuracy of the lung dispersion detection device is lower.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a gas concentration detection device which can improve the accuracy of a gas concentration detection result.

To achieve the above object, an embodiment of the present application provides a gas concentration detection apparatus, including: the infrared light source, the convex lens, the air chamber, the infrared detector and the data processing unit;

the infrared light source and the infrared detector are respectively and fixedly arranged at two ends of the air chamber, and the convex lens is arranged at one side of the infrared light source;

the infrared light emitted by the infrared light source sequentially passes through the convex lens and the air chamber and then irradiates on a photosensitive element of the infrared detector;

the gas chamber is filled with gas to be tested;

the data processing unit is used for calculating the concentration value of the gas component to be detected in the gas to be detected according to the electric signal detected by the infrared detector.

In some embodiments, the probe of the infrared detector is externally wrapped with a heat conduction tube, and a heat conduction wire is wound around the peripheral wall of the heat conduction tube.

In some embodiments, a first temperature sensor is arranged between the infrared detector and the heat conduction cylinder, and the first temperature sensor is used for measuring the infrared detector temperature of the infrared detector; the heat conducting wire is used for carrying out constant temperature control on the heat conducting cylinder according to the temperature of the infrared detector and a preset temperature threshold value.

In some embodiments, the plenum is provided with an air inlet, an air outlet, and an air pump; the gas inlet is used for guiding the gas to be measured into the gas chamber; the gas outlet is used for discharging the gas to be tested; the air pump is used for pumping the gas to be detected discharged from the air outlet so as to accelerate the flow speed of the gas to be detected.

In some embodiments, the gas chamber is provided with a gas pressure sensor for detecting the gas pressure of the gas to be measured in the gas chamber; the gas concentration detection device is also provided with a second temperature sensor, and the second temperature sensor is used for measuring the temperature of the gas chamber; the data processing unit is also used for correcting the gas concentration according to the gas pressure and the gas chamber temperature.

In some embodiments, the gas concentration detection apparatus further includes a light source end filter, where the light source end filter is disposed behind the convex lens, and the light source end filter is configured to filter out infrared light in a preset band; the preset wave band is an overlapped wave band for absorbing the infrared light by different gas components to be detected.

In some embodiments, the gas concentration detection apparatus includes a light source end mount for eliminating the infrared light within a first predetermined angular range that is scattered from the infrared light source.

In some embodiments, the gas concentration detection apparatus further comprises a probe end mount for eliminating the infrared light scattered from the gas chamber within a second predetermined angular range.

In some embodiments, the device further comprises a detection end convex lens, and the infrared light emitted by the infrared light source sequentially passes through the convex lens and the air chamber, and then is condensed by the detection end convex lens and irradiates on a photosensitive element of the infrared detector.

In some embodiments, the infrared detector is a pyroelectric sensor or a thermopile sensor.

The gas concentration detection device provided by the embodiment of the application comprises an infrared light source, a convex lens, an air chamber, an infrared detector and a data processing unit, wherein the infrared light source and the infrared detector are respectively fixedly arranged at two ends of the air chamber, and the convex lens is arranged at one side of the infrared light source; when the gas concentration is detected, scattered light emitted by the infrared light source is concentrated through the convex lens, so that more infrared light enters the gas chamber, the light signal intensity in the gas chamber is enhanced, in addition, the scattering degree of the infrared light is enhanced, the optical path of the infrared light in the gas chamber is increased, the infrared light absorptivity is improved, and the intensity of an electric signal and the subsequent gas concentration detection precision are improved; the infrared light passes through the convex lens and the air chamber in sequence, and part of the infrared light is absorbed by the gas to be detected in the air chamber and finally irradiates on a photosensitive element of the infrared detector; and the infrared detector receives the final optical signal and outputs a corresponding electric signal, and finally the data processing unit calculates the gas concentration according to the electric signal. The gas concentration detection device provided by the embodiment of the application guarantees the accuracy of detecting the gas concentration by the gas concentration detection device, and solves the problem of low gas concentration detection accuracy of the existing gas concentration detection device.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings are included to provide a further understanding of the technical aspects of the present application, and are incorporated in and constitute a part of this specification, illustrate the technical aspects of the present application and together with the examples of the present application, and not constitute a limitation of the technical aspects of the present application.

FIG. 1a is a schematic block diagram of a gas concentration detection apparatus according to an embodiment of the present disclosure;

fig. 1b is a schematic diagram of module connection of a gas concentration detection apparatus according to an embodiment of the present application.

Reference numerals: 100, a light source module; 110, an infrared light source; 120, a light source end convex lens; 130, a light source end base; 140, a light source end filter; 200, an air circuit module; 210, a gas chamber; 220, an air inlet; 230, an air outlet; 240, an air pressure sensor; 250, an air pump; 300, an infrared light intensity detection module; 310, an infrared detector; 311, a first window tab; 312, a second window; 320, a first temperature sensor; 330, a heat conducting wire; 340, detecting an end convex lens; 350, detecting end lenses; 360, probe end base.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

It should be noted that although functional block division is performed in a device diagram and a logic sequence is shown in a flowchart, in some cases, the steps shown or described may be performed in a different order than the block division in the device, or in the flowchart. The terms first, second and the like in the description and in the claims and in the above-described figures, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

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 is for the purpose of describing embodiments of the present application only and is not intended to be limiting of the present application.

First, several nouns referred to in this application are parsed:

pulmonary dispersion: refers to the process of gas exchange between alveoli and blood vessels. As respiratory gases enter the alveoli, oxygen will pass from the alveoli through the alveolar membrane into the blood, while carbon dioxide passes from the blood through the alveolar membrane into the alveoli, eventually expelling carbon dioxide out of the body by respiration. This gas exchange is achieved by a pulmonary diffusion process in which the weakness of the alveolar membrane allows oxygen and carbon dioxide to pass relatively easily to meet the body's demand for oxygen and to exclude carbon dioxide from metabolism.

Lambert-Beer Law: also known as beer-lambert's law, is one of the laws describing optical absorption, applicable to all electromagnetic radiation and all light absorbing substances, including gases, solids, liquids, molecules, atoms and ions. The beer-lambert law states that the amount of light absorbed is proportional to the number of molecules in the optical path that produce light absorption.

T90 response time: in the present embodiment, T90 response time refers to the time it takes for a gas detector to read from 0 to 90% of the measured gas concentration in the environment, with a shorter T90 response time generally meaning that the system is more sensitive to changes.

Pulmonary dispersion refers to the process of gas exchange of oxygen and carbon dioxide in the lungs through the alveoli and the walls of the pulmonary capillaries, i.e. the ability of alveolar gas to diffuse from the alveoli to the capillaries through the alveolar membrane into the blood and bind with hemoglobin in the erythrocytes. The diffuse function is a measure of the effectiveness of ventilation for the alveolar-capillary membrane for gas exchange. The lung diffusion examination has important guiding significance in medicine, and can be used for detecting lung and airway lesions, evaluating the severity and prognosis of diseases, evaluating the curative effect of medicines or other treatment methods, identifying the cause of dyspnea, diagnosing lesion sites, evaluating the tolerance of lung functions to operation or the tolerance of labor intensity and the like. Carbon monoxide is an ideal gas for detecting pulmonary dispersion function because the binding capacity of carbon monoxide and hemoglobin is one hundred times greater than that of oxygen, and is widely used in clinical tests. During the lung dispersion test, the subject exhales to the residual gas position, then inhales the mixed gas containing 0.3% of carbon monoxide and 0.3% of methane to the total lung position, exhales to the residual gas position after holding the breath for a period of time, continuously measures the gas concentration of the carbon monoxide and the methane in the exhaling process, and traces a breathing capacity curve and a test gas concentration curve. In order to calculate the carbon monoxide concentration, it is necessary to measure the alveolar carbon monoxide concentration after breath-hold at the beginning of dispersion, that is, the concentration change of carbon monoxide gas before and after exhalation, and the carbon monoxide concentration after exhalation can be directly measured from the exhaled gas, and since methane does not bind with hemoglobin in the alveoli, the carbon monoxide concentration before exhalation can be indirectly calculated from the methane gas concentration.

Existing lung dispersion function detection devices typically utilize a quantitative relationship between the amount of absorption of light of a particular wavelength by carbon monoxide gas and the concentration of carbon monoxide gas. However, the existing lung dispersion detection device adopts an infrared steady-state light source, the angle of light scattered by the infrared steady-state light source is larger and is about 20-30 degrees, so that a plurality of light does not enter the air chamber, and an effective light signal finally irradiated on the detector is lost to a certain extent, so that the gas concentration accuracy of the lung dispersion detection device is lower.

Based on this, provided in this embodiment of the application is a gas concentration detection apparatus, and it is aimed at solving the problem that the existing gas concentration detection apparatus loses the optical signal, and improving the accuracy of gas detection by the gas concentration detection apparatus.

The application embodiment provides a gas concentration detection device, and the gas concentration detection device is specifically described by the following embodiment.

Fig. 1a is a schematic block diagram of a gas concentration detection apparatus according to an embodiment of the present application, and fig. 1b is a schematic block diagram of a gas concentration detection apparatus according to an embodiment of the present application. In the embodiment of the present invention, the gas concentration detection apparatus includes a light source module 100, a gas path module 200, an infrared light intensity detection module 300, and a data processing unit 400.

The light source module 100 includes an infrared light source 110 and a light source end convex lens 120, the infrared light source 110 is used for emitting infrared light in different wavebands, the light source end convex lens 120 is placed between the infrared light source 110 and the light source end optical filter 140, because the irradiation area of the infrared light source 110 is larger than the cross-sectional area of the air chamber 210, the light source end convex lens 120 can have a condensing function, the light scattered by the infrared light source 110 is condensed, so that more light enters the air chamber 210, thereby increasing the intensity of optical signals in the air chamber 210, further increasing the scattering degree of the infrared light, the stronger the scattering degree of the infrared light, the number of times that the infrared light is reflected in the air chamber 210 is increased, the optical path of the infrared light in the air chamber is also increased, and therefore the infrared light absorptivity is improved, thereby improving the intensity of electric signals and the detection precision of subsequent gas concentration.

The type of gas concentration detection device determines the need to modulate the infrared light source with a certain frequency, and the existing gas concentration detection device adopts continuous infrared heat radiation type light sources, such as infrared heating elements of the nickel-gas wire, the silicon carbide rod and the like. The infrared light source has the problems of large heat capacity, poor vibration resistance, large power consumption, long preheating time and high failure rate, and if the light source is directly electrically modulated, the optical power can be greatly reduced under high-frequency power supply, so that the resolution and the response speed are limited. If the modulation of the light source adopts a mechanical chopping scheme, the defects of large volume, large power consumption, low stability and the like are also caused, so that the embodiment of the application adopts a miniature pulse infrared light source with high-intensity output.

The multi-layer thermal resistance film of the infrared light source 110 can be made of amorphous carbon material, the infrared light source 110 generates heat and generates infrared radiation after passing current, the absorption peak of carbon monoxide at the middle infrared band (lambda=4.64 μm) is strongest, and the spectrum range of the light output by the infrared light source 110 is 1.0-20 μm, and covers the absorption band of carbon monoxide. The light source can bear high temperature of 750 ℃ at maximum, has high emissivity, high heat conductivity and extremely low heat residence property, can be rapidly heated and cooled when the modulation frequency is 0-100 Hz pulse, and reduces the preheating time required by the use of the gas concentration detection device. In some embodiments, the infrared light source 110 is powered by a separate light source board, the infrared light source 110 is welded to the light source board, and important power supply parts of the light source, such as a linear voltage stabilizer, a constant power circuit and an electronic switch MOS tube, are moved to the light source board, and the light source board is placed close to the light source, so that the power supply lead of the light source is reduced, and the anti-interference capability of the light source is improved. In addition, the voltage stabilizing source consisting of the switching power supply and the linear low-dropout voltage stabilizer supplies power to the front stage of the infrared light source 110, so that the noise level can be reduced by 2 to 3 orders of magnitude.

To detect multiple gases simultaneously, the infrared light source 110 emits light at a corresponding wavelength for each gas that is capable of being absorbed by the gas, and in some embodiments, the infrared light source 110 emits a single beam of infrared light at three wavelengths, one that is capable of being absorbed by carbon monoxide (CO) gas, one that is capable of being absorbed by methane (CH 4) gas, and the last one that is not absorbed by any gas, the wavelength that is not absorbed by any gas being the reference wavelength.

The air circuit module 200 includes an air chamber 210, an air pressure sensor 240, and an air pump 250. The air chamber 210 is used for introducing a gas to be measured, where the gas to be measured may be a gas exhaled by a preset object, or may be air, which is not specifically limited in this embodiment of the present application. In the lung diffusion function test scenario, the gas to be tested may be the gas exhaled by the subject, including carbon monoxide, methane, etc.

The chamber 210 may be a tubular channel of copper plated with gold, and the infrared light is scattered into the chamber 210, so that the inner wall of the chamber 210 reflects the infrared light, and if the reflectivity of the inner wall is too low, a part of the optical signal is lost. Therefore, the inner wall of the gas chamber 210 may be gold-plated and as smooth as possible to improve the light energy utilization rate, so that the loss of the light signal reaching the infrared detector 310 is small, and the reliability of the gas concentration detection result is ensured. The length of the air cell 210 has a positive correlation with the absorption coefficient of optical power, and thus, in order to improve the absorption rate of the gas, the air cell 210 is preferably designed to be slim.

The infrared light intensity detection module 300 comprises an infrared detector 310, the infrared detector 310 is connected with the air chamber 210, the surface of the infrared detector 310 receives infrared light, and the infrared detector 310 is used for detecting infrared light intensity of the infrared light.

In some embodiments, the infrared detector 310 is provided with a first window sheet 311 and a second window sheet 312, so that the infrared detector 310 has a gas channel corresponding to the first window sheet 311 and a reference channel corresponding to the second window sheet 312, the first window sheet 311 is used for allowing infrared light after gas absorption to pass through to obtain first infrared light, and the second window sheet 312 is used for allowing infrared light not absorbed by gas to pass through to obtain second infrared light; the infrared detector 310 is configured to detect a first infrared light intensity of the first infrared light and a second infrared light intensity of the second infrared light, and output an electrical signal related to the first infrared light intensity in the gas channel and an electrical signal related to the second infrared light intensity in the reference channel.

It should be noted that, after the original multi-wavelength infrared light passes through the window, the infrared light with one wavelength is filtered out and enters the infrared detector 310. The gas to be measured includes a plurality of gas components, and the gas components can absorb infrared light in a specific wavelength range. The first window sheet 311 is for passing infrared light absorbed by the gas component. The second window sheet 312 is used to pass infrared light that is not absorbed by any of the gas components. Since the infrared light rays passing through the second window 312 are not absorbed by any gas, the intensity of the infrared light on the reference channel is hardly lost.

The data processing unit 400 is used for calculating the concentration value of the gas component to be detected in the gas to be detected according to the electric signal detected by the infrared detector, and the data processing unit 400 is used for calculating the gas concentration of the gas component to be detected according to the electric signal of the gas channel and the electric signal of the reference channel based on the lambert-beer law.

Wherein, the related calculation formula of absorbance A (absorptance) is shown in formula 1:

absorbance a (absorptance) describes the degree of light intensity decay after light passes through a medium.

In some embodiments, the gas components to be measured may be carbon monoxide (CO) gas and methane (CH 4) gas.

In addition, the data processing unit 400 is further connected to the light source module, and the data processing unit 400 is further configured to electrically modulate the light source.

The gas concentration detection device of this embodiment includes infrared light source, convex lens, air chamber, infrared detector and data processing unit, infrared light source and infrared detector are fixed the both ends that set up at the air chamber respectively, convex lens sets up in infrared light source one side, infrared light that the infrared light source sent is gathered by convex lens, make more infrared light get into the air chamber, thereby the light signal intensity in the air chamber has been strengthened, in addition, the scattering degree of infrared light has also been strengthened, make the optical path of infrared light in the air chamber increase, the infrared light absorptivity has been improved, thereby improve the intensity of electrical signal, by the gas absorption part that awaits measuring in the air chamber when infrared light passes through the air chamber, output corresponding electrical signal after final infrared detector received the optical signal, final data processing unit carries out the calculation of gas concentration according to this electrical signal. The device has improved the accuracy that gas concentration detected, has solved the lower problem of current gas concentration detection device accuracy.

In some embodiments, the infrared detector 310 has a heat conducting tube, a first temperature sensor 320 is disposed between the infrared detector 310 and the heat conducting tube, the first temperature sensor 320 is disposed on the surface of the infrared detector 310 and is used for measuring the temperature of the infrared detector 310, the heat conducting tube is wound with a heat conducting wire 330, the heat conducting wire 330 is used for heating the heat conducting tube according to the temperature of the infrared detector and a preset temperature threshold, specifically, the temperature of the infrared detector and the preset temperature threshold are compared, if the temperature of the infrared detector is smaller than the preset temperature threshold, the heat conducting wire 330 is controlled to heat the heat conducting tube, if the temperature is greater than or equal to the preset temperature threshold, the heating is stopped, the closed loop constant temperature control of the heat conducting wire 330 is realized, the operation temperature of the infrared detector 310 is facilitated to be maintained, and the operation of the heat conducting wire is ensured within a proper temperature range, wherein the preset temperature threshold can be 40 ℃.

The heat conduction tube is heated by controlling the heat conduction wire 330, and the heat conduction tube heats the infrared detector 310 through heat conduction, so that the temperature of the infrared detector 310 is higher than the ambient temperature, and the influence of the change of the ambient temperature on the infrared detector signal can be reduced. The heat conduction tube slowly heats the infrared detector 310 through heat conduction, so that abrupt change of the temperature of the infrared detector 310 caused by the change of overshoot during temperature closed-loop control adjustment can be avoided.

In some embodiments, the gas chamber 210 is provided with a gas inlet 220, a gas outlet 230, and a gas pressure sensor 240, the gas inlet 220 is used to introduce the gas to be measured into the gas chamber 210, the gas outlet 230 is used to discharge the gas to be measured, the gas pressure sensor 240 is used to detect the gas pressure of the gas to be measured in the gas chamber 210, and in some embodiments, the gas pressure sensor 240 may be disposed at the gas outlet 230.

The gas concentration detection apparatus is further provided with a second temperature sensor for measuring the temperature of the gas chamber 210, the second temperature sensor may be disposed inside the infrared detector 310, the data processing unit 400 may obtain data collected by the gas pressure sensor 240 and the second temperature sensor, and the data processing unit 400 is configured to correct the gas concentration according to the gas pressure and the temperature of the gas chamber.

Specifically, calibration of the gas detection system may be performed in advance, calibration measurement may be performed at a plurality of temperature and pressure points, and based on these data, a functional relationship between the electrical signal output by the infrared detector 310 and the correlation between the gas chamber temperature and the gas chamber gas pressure may be calculated and generated, so as to obtain the parameter compensation algorithm formula. In an actual use scene, substituting the temperature and pressure data of the current environment into a parameter compensation algorithm formula to calculate a corresponding compensation coefficient. The data processing unit 400 calculates the gas concentration of the gas based on the lambert-beer law and the reference channel electric signal, takes the gas concentration as an initial concentration value, multiplies the initial concentration value by a compensation coefficient calculated in advance, and obtains a final compensated concentration value.

In some embodiments, the gas circuit module 200 further includes a pump 250, where the pump 250 is configured to pump the gas to be measured discharged from the gas outlet 230, so as to accelerate the flow speed of the gas to be measured in the gas chamber 210.

It should be noted that, lengthening the gas chamber 210 also increases the time for the gas to pass through the gas chamber 210, which ultimately affects the T90 response time of the gas analysis module, and thus the air pump 250 is additionally connected to the air outlet 230, so that the gas accelerates through the gas chamber 210, thereby reducing the T90 response time. The air pump 250 is also connected with the data processing unit 400, the data processing unit 400 controls the air pump 250 to be switched on or off, and the air pump 250 can send a signal to the data processing unit 400 to indicate whether the working state of the air pump is on or off.

In some embodiments, the light source module 100 further includes a light source end filter 140, the light source end filter 140 is disposed between the light source end convex lens 120 and the air chamber 210, and the light source end filter is disposed behind the convex lens and is used for filtering infrared light of a preset wave band; the preset wave band is an overlapped wave band for absorbing the infrared light by different gas components to be detected.

For example, in the process of detecting the gas concentration, only the gas concentration of the carbon monoxide gas is required to be detected, but the to-be-detected gas entering the gas chamber 210 may also have carbon dioxide gas, at this time, carbon monoxide and carbon dioxide are both components of the to-be-detected gas, the absorption spectrum of carbon dioxide is similar to that of carbon monoxide, and the absorption coefficient of carbon dioxide is far higher than that of carbon monoxide, if the carbon dioxide is not processed, the carbon dioxide gas will also absorb infrared light with a wavelength corresponding to that of the carbon monoxide gas when the concentration of the carbon monoxide gas is detected, so as to affect the detection result. The light source end filter 140 is designed to filter out light of a wavelength in which carbon monoxide and carbon dioxide overlap and absorb, so that the influence of carbon dioxide gas on gas concentration detection can be completely removed.

In addition, the light source side filter 140 can also be used to seal the plenum 210.

In some embodiments, the light source module 100 further includes a light source end base 130, where the light source end base 130 is configured to eliminate the infrared light within the first preset angle range scattered by the infrared light source 110, so that the infrared light with a large angle is difficult to enter the air chamber.

The light source end base 130 wraps the light emitting end of the infrared light source 110 and the light source end convex lens 120, so that the infrared light source 110 and the light source plate, the light source end convex lens 120 and the air chamber 210 thereof can be fixed, meanwhile, the material of the light source end base 130 is a low-reflection material, and large-angle light scattered by the infrared light source 110 can be eliminated as stray light.

In the scenario of using the gas detection apparatus based on NDIR principle, the geometric center connecting line of the opening shapes at two ends of the gas chamber 210 is taken as a reference line, for example, the opening shapes at two ends of the gas chamber 210 are all circular, at this time, the connecting line of the circle centers at two ends is taken as the reference line, the included angle formed by any one infrared light emitted by the infrared light source 110 and the reference line is a first preset angle, and the first preset angle range may be 20-30 °.

In some embodiments, the infrared light intensity detection module 300 further includes a detection end base 360, where the detection end base 360 is configured to eliminate infrared light scattered from the plenum 210 within a second predetermined angular range, such that the angle of light striking the first window and the second window by the infrared light is reduced. In the case of using the NDIR principle-based gas detection apparatus, the geometrical center line of the shape of the openings at both ends of the gas chamber 210 is used as a reference line, and the included angle formed by any one infrared ray scattered from the gas chamber 210 and the reference line is a second preset angle, and the second preset angle may be 20-30 °.

The angle of the light scattered by the infrared steady-state light source adopted by some gas concentration detection equipment based on the NDIR principle is larger and is about 20-30 degrees, the angle of the light entering the infrared detector after passing through the gas chamber is also 20-30 degrees, and the problem that the performance index of the optical filter is influenced by the incident angle exists at the infrared detector. The larger incident angle can cause wavelength drift of a narrow-band filter of a channel on the infrared detector, thereby affecting the accuracy of gas absorption. In this regard, the light source end base 130 can reduce the large angle light entering the air chamber, and the detection end base 360 can absorb the large angle light entering the detection end, so that the angle of the light finally reaching the infrared detector 310 is smaller, and the influence of wavelength drift of the window sheet is reduced.

In some embodiments, the infrared detector may be a pyroelectric sensor or a thermopile sensor. Thermopile sensors based on thermopile sensing technology utilize thermocouples to detect temperature changes in gas molecules, generating a thermoelectric potential, and finally the sensor outputs a voltage proportional to the concentration of the gas to be detected. The detection principle of the pyroelectric gas sensor is that the pyroelectric effect is utilized, and the output voltage is created by detecting the change of the received infrared radiation quantity, so that the pyroelectric gas sensor has the advantages of long service life, high sensitivity, good stability, high precision and the like.

In some embodiments, the infrared light intensity detection module 300 further includes a detection end convex lens 340, where the detection end convex lens 340 is disposed between the air chamber 210 and the infrared detector 310, and after the infrared light emitted by the infrared light source 110 sequentially passes through the light source end convex lens 120 and the air chamber 210, the infrared light may be condensed by the detection end convex lens 340 and then irradiated onto a photosensitive element of the infrared detector. The detection end convex lens 340 is used for gathering infrared light, so that more infrared light is emitted into the receiving surface of the infrared detector, the optical power finally received by the infrared detector 310 is improved, and the signal-to-noise ratio of the output signal of the infrared detector 310 can be effectively improved.

In some embodiments, the infrared light intensity detection module 300 further includes a detection end lens 350, the detection end lens 350 being disposed between the plenum 210 and the detection end convex lens 340, the detection end lens 350 may be a conventional sapphire window sheet for sealing the plenum 210.

The embodiments described in the embodiments of the present application are for more clearly describing the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application, and as those skilled in the art can know that, with the evolution of technology and the appearance of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

It will be appreciated by those skilled in the art that the technical solutions shown in the figures do not constitute limitations of the embodiments of the present application, and may include more or fewer steps than shown, or may combine certain steps, or different steps. Those of ordinary skill in the art will appreciate that all or some of the steps of the methods, systems, functional modules/units in the devices disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof.

The above described apparatus embodiments are merely illustrative, wherein the units illustrated as separate components may or may not be physically separate, i.e. may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

The terms "first," "second," "third," "fourth," and the like in the description of the present application and in the above-described figures, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the present application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It should be understood that in this application, "at least one" means one or more, and "a plurality" means two or more. "and/or" for describing the association relationship of the association object, the representation may have three relationships, for example, "a and/or B" may represent: only a, only B and both a and B are present, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b or c may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of elements is merely a logical functional division, and there may be additional divisions of actual implementation, e.g., multiple elements or components may be combined or integrated into another system, or some features may be omitted, or not performed. The coupling or direct coupling or communication connection shown or discussed with each other may be through some interface, device or unit indirect coupling or communication connection, which may be in electrical, mechanical or other form.

Preferred embodiments of the disclosed embodiments are described above with reference to the accompanying drawings, and thus do not limit the scope of the claims of the disclosed embodiments. Any modifications, equivalent substitutions and improvements made by those skilled in the art without departing from the scope and spirit of the embodiments of the present disclosure shall fall within the scope of the claims of the embodiments of the present disclosure.

Claims (10)

1. A gas concentration detection apparatus, characterized in that the apparatus comprises: the infrared light source, the convex lens, the air chamber, the infrared detector and the data processing unit;

the infrared light source and the infrared detector are respectively and fixedly arranged at two ends of the air chamber, and the convex lens is arranged at one side of the infrared light source;

the infrared light emitted by the infrared light source sequentially passes through the convex lens and the air chamber and then irradiates on a photosensitive element of the infrared detector;

the gas chamber is filled with gas to be tested;

the data processing unit is used for calculating the concentration value of the gas component to be detected in the gas to be detected according to the electric signal detected by the infrared detector.

2. The gas concentration detection apparatus according to claim 1, wherein the probe of the infrared detector is externally wrapped with a heat conduction tube, and a heat conduction wire is wound around a peripheral wall of the heat conduction tube.

3. The gas concentration detection apparatus according to claim 2, wherein a first temperature sensor for measuring a detector temperature of the infrared detector is provided between the infrared detector and the heat conductive cylinder; the heat conducting wire is used for carrying out constant temperature control on the heat conducting cylinder according to the temperature of the detector and a preset temperature threshold value.

4. The gas concentration detection apparatus according to claim 1, wherein the gas chamber is provided with a gas inlet, a gas outlet, and a suction pump; the gas inlet is used for guiding the gas to be measured into the gas chamber; the gas outlet is used for discharging the gas to be tested; the air pump is used for pumping the gas to be detected discharged from the air outlet.

5. The gas concentration detection apparatus according to claim 4, wherein the gas chamber is provided with a gas pressure sensor for detecting a gas pressure of the gas to be detected in the gas chamber; the gas concentration detection device is also provided with a second temperature sensor, and the second temperature sensor is used for measuring the temperature of the gas chamber; the data processing unit is also used for correcting the gas concentration according to the gas pressure and the gas chamber temperature.

6. The gas concentration detection apparatus according to any one of claims 1 to 5, further comprising a light source end filter disposed behind the convex lens, the light source end filter being configured to filter out infrared light of a preset wavelength band; the preset wave band is an overlapped wave band for absorbing the infrared light by different gas components to be detected.

7. The gas concentration detection apparatus according to any one of claims 1 to 5, further comprising a light source end base for eliminating the infrared light in the first preset angular range that is scattered from the infrared light source.

8. The gas concentration detection apparatus according to any one of claims 1 to 5, further comprising a detection end base for eliminating the infrared light scattered from the gas chamber in a second preset angular range.

9. The gas concentration detection apparatus according to any one of claims 1 to 5, further comprising a detection-end convex lens, wherein the infrared light emitted from the infrared light source passes through the convex lens and the gas chamber in order, and is condensed by the detection-end convex lens, and then irradiates on a photosensitive element of the infrared detector.

10. The gas concentration detection apparatus according to any one of claims 1 to 5, wherein the infrared detector is a pyroelectric sensor or a thermopile sensor.