WO2023015605A1

WO2023015605A1 - Laser detection apparatus, organic carbon and elemental carbon analyzer, and laser detection method

Info

Publication number: WO2023015605A1
Application number: PCT/CN2021/114127
Authority: WO
Inventors: 刘海东; 周旭; 彭文姣; 郭艳
Original assignee: 力合科技（湖南）股份有限公司
Priority date: 2021-08-13
Filing date: 2021-08-23
Publication date: 2023-02-16
Also published as: CN113670855B; CN113670855A

Abstract

A laser detection apparatus (8), an organic carbon and elemental carbon analyzer (1000), and a laser detection method. The laser detection apparatus (8) comprises a first laser emitter (811), a first laser detector (82) and a second laser detector (83), wherein the first laser emitter (811) is arranged on the side of the back face of a filter membrane (23), and is used for emitting a laser towards the filter membrane (23), and part of the emitted laser passes through the filter membrane (23) to form a first transmitted laser, and the other part of the emitted laser is reflected by the filter membrane (23) to form a first reflected laser; the first laser detector (82) is used for receiving the first transmitted laser; and the second laser detector (83) is used for receiving the first reflected laser. Since the first laser emitter (811) is arranged on the side of the back face of the filter membrane (23), the effect of the first transmitted laser that is generated by the intensity of a light source and the optical properties of the filter membrane (23) can be eliminated according to the first reflected laser, and laser intensity change data which is affected by only a sample concentration on the front face of the filter membrane (23) is calculated. When the laser detection method is applied to the organic carbon and elemental carbon analyzer (1000), accurate separation of organic carbon and elemental carbon can be realized.

Description

Laser detection device, organic carbon carbon analyzer and laser detection method

technical field

The invention relates to the technical field of air quality detection, in particular to a laser detection device, an organic carbon carbon analyzer using the laser detection device and a laser detection method.

Background technique

In recent years, with the continuous development of the global social economy and the continuous expansion of the city scale, the air quality problem has become increasingly severe. The detection of organic carbon and elemental carbon content in air particulate matter is of great importance for the study of atmospheric chemical reactions and source apportionment of pollutants. Significance has become a hot spot in the field of environmental monitoring today.

The measurement methods of organic carbon and elemental carbon in air particulate matter include thermal method, optical method and thermo-optical method. The thermal method mainly distinguishes organic carbon and elemental carbon according to their different thermal properties. However, during the heating process, organic carbon will be partially cracked and carbonized, and a substance with thermal and optical properties similar to elemental carbon will be formed, resulting in high elemental carbon measured. . Due to the limitation of its principle, the optical method can only be used to measure elemental carbon.

At present, the most widely used and recognized mature organic carbon and elemental carbon analysis method is the thermo-optical method. Its working principle is to collect particulate matter in the air through filter membrane filtration, and then pass through an oxygen-free carrier gas to make the filter membrane in an oxygen-free environment. At this time, the temperature of the filter membrane is raised step by step, so that the organic carbon on the surface of the filter membrane (and a part of it is carbonized to form cracked carbon) is pyrolyzed and escapes into the oxidation furnace to be oxidized and converted into carbon dioxide, and then the aerobic load is introduced into the desorption furnace. The air makes the filter membrane in an aerobic environment, and continues to raise the temperature of the filter membrane step by step, so that the elemental carbon in the filter membrane is pyrolyzed and escapes into the oxidation furnace to be oxidized and converted into carbon dioxide, so that the carbon dioxide concentration output by the oxidation furnace is detected by a carbon dioxide detector. Calculate the content of organic carbon and elemental carbon. During the whole process, there is a laser beam hitting the filter membrane, and its transmitted light (or reflected light) will be weakened when the organic carbon is carbonized. As the oxygen-free carrier gas is switched to an oxygen carrier gas, and the temperature rises, the elemental carbon will be oxidized and decomposed, and the light intensity of the transmitted light (or reflected light) of the laser beam will gradually increase. When it returns to the original transmission ( or reflected) light intensity, this moment is considered as the separation point of organic carbon and elemental carbon, that is, all carbon detected before this moment is considered as organic carbon (OC), and all carbon detected after this time is considered as elemental carbon (EC). Thermo-optic method is an integrated optical method to correct the cracked carbon generated during the analysis of organic carbon at elevated temperature. However, since the intensity of transmitted light (reflected light) is not only affected by the concentration of cracked carbon and elemental carbon, but also by the intensity of the light source and the optical properties of the filter membrane, in the prior art, only the influence on the fluctuation of the light source is considered The correction was made without considering the influence of other factors such as the change of the properties of the filter membrane on the intensity of the transmitted light (reflected light), which resulted in the inability to accurately determine the split point of organic carbon/elemental carbon.

Contents of the invention

The invention provides a laser detection device, an organic carbon elemental carbon analyzer and a laser detection method to solve the technical problem that the separation point of organic carbon/elemental carbon cannot be accurately determined.

According to one aspect of the present invention, a laser detection device is provided, including a laser emitter, a first laser detector and a second laser detector, the laser emitter is used to emit laser light toward the filter membrane, and the first laser detector , the second laser detector is respectively used to receive the transmitted laser light passing through the filter membrane and the reflected laser light reflected by the filter membrane, and the laser emitter includes a first laser emitter arranged on the back side of the filter membrane Part of the laser light emitted by the first laser transmitter toward the filter membrane passes through the filter membrane to form a first transmitted laser light, and part of it is reflected by the filter membrane to form a first reflected laser light. The detector is arranged on the front side of the filter membrane and used to receive the first transmitted laser light, and the second laser detector is arranged on the back side of the filter membrane and used to receive the first reflected laser light.

Preferably, the laser emitter further includes a second laser emitter disposed on the front side of the filter membrane, and part of the laser light emitted by the second laser emitter towards the filter membrane passes through the filter membrane A second transmitted laser light is formed and received by the second laser detector, and part of it is reflected by the filter film to form a second reflected laser light and received by the first laser detector.

Further, the laser modulation frequencies of the first laser transmitter and the second laser transmitter are different, and both the first laser detector and the second laser detector are equipped with a frequency demodulation module and can pass through the The above-mentioned frequency demodulation module distinguishes and measures lasers with different modulation frequencies.

Further, the laser detection device further includes a first beam splitter arranged at the front end of the first laser emitter and a second beam splitter arranged at the front end of the second laser emitter, the first beam splitter and the The second beam splitters are all inclined relative to the surface of the filter membrane; the light emitting direction of one of the laser emitters in the first laser emitter and the second laser emitter is towards the filter membrane, and the emitted At least part of the laser light passes through the beam splitter at its front end and illuminates the filter film; the light output direction of another laser emitter staggers the filter film, and at least part of the laser light emitted is reflected by the beam splitter at its front end and then shines on the filter film. The filter membrane.

Further, the laser detection device also includes a first spectroscopic sheet arranged at the front end of the first laser emitter, the first spectroscopic sheet is inclined relative to the surface of the filter membrane, and the output light of the first laser emitter direction towards the filter film, the light incident direction of the second laser detector is staggered from the filter film, and at least part of the laser light emitted by the first laser emitter passes through the first beam splitter and shines on the filter film. film, the first reflected laser light can enter the second laser detector after being reflected by the first beam splitter and changing its direction.

According to the second aspect of the present invention, there is also provided a carbon analyzer for organic carbon, comprising an analysis furnace, the analysis furnace includes an analysis furnace tube and a filter membrane arranged in the analysis furnace tube, and is arranged in the analysis furnace The analysis furnace heating device on the tube, the filter membrane is used to collect the particulate matter in the sample gas flowing through the analysis furnace tube, the organic carbon element carbon analyzer also includes the above-mentioned laser detection device, and the first laser emits The detector and the second laser detector are arranged at the end of the analysis furnace tube corresponding to the back of the filter membrane, and the first laser detector is arranged at the end of the analysis furnace tube corresponding to the front of the filter membrane.

Preferably, the desorption furnace also includes a sealed cavity arranged around the outer circumference of the desorption furnace tube and enclosed with the desorption furnace tube, and the desorption furnace heating device is arranged in the sealed cavity; the organic carbon The elemental carbon analyzer also includes an intake valve group and a first gas delivery pipeline connected to the intake valve group, the first gas delivery pipeline communicates with the sealed chamber and is used to output the intake valve group A shielding gas is introduced into the sealed cavity.

Further, the organic carbon carbon analyzer also includes a power pump and a first exhaust pipeline, the first exhaust pipeline and the first gas transmission pipeline are respectively arranged on opposite sides of the sealed chamber, and the The end of the first exhaust pipe away from the sealed chamber is connected to the power pump, and the power pump is used to discharge the gas in the sealed chamber.

According to a third aspect of the present invention, a laser detection method is also provided, and the above-mentioned laser detection device is used for detection, and the laser detection method includes the following steps:

S100: Use the first laser emitter to emit laser light toward the back of the filter membrane, and make the laser emitted by the first laser emitter partially pass through the filter membrane to form a first transmitted laser light, and part of it is reflected by the filter membrane to form a first laser beam. Reflecting laser light, the intensity of the first transmitted laser light is affected by the intensity of the light source, the optical properties of the filter membrane and the sample concentration on the front of the filter membrane, and the intensity of the first reflected laser light is affected by the intensity of the light source and the optical properties of the filter membrane;

S200: Receive the first transmitted laser light through a first laser detector, and receive the first reflected laser light through a second laser detector;

S300: According to the intensity change data of the first reflected laser light, eliminate the influence of the light source intensity and the change of the optical properties of the filter film in the first transmitted laser light, and calculate the laser light only affected by the concentration of the sample on the front side of the filter film Intensity change data.

Further, when the laser detection device further includes a second laser emitter, the laser detection method includes the following steps:

S100: Use the first laser emitter to emit laser light toward the back of the filter membrane, and make the laser emitted by the first laser emitter partially pass through the filter membrane to form a first transmitted laser light, and part of it is reflected by the filter membrane to form a first laser beam. Reflecting laser light, the intensity of the first transmitted laser light is affected by the intensity of the light source, the optical properties of the filter membrane and the sample concentration on the front of the filter membrane, and the intensity of the first reflected laser light is affected by the intensity of the light source and the optical properties of the filter membrane; through the second The laser emitter emits laser light toward the front of the filter membrane, and part of the laser light emitted by the second laser emitter passes through the filter membrane to form a second transmitted laser light, and part of it is reflected by the filter membrane to form a second reflected laser light. Both the second transmitted laser light and the second reflected laser light are affected by the intensity of the light source, the optical properties of the filter membrane and the concentration of the sample on the front of the filter membrane;

S200: Receive the first transmitted laser light and the second reflected laser light through the first laser detector, and receive the first reflected laser light and the second transmitted laser light through the second laser detector;

S300: According to the intensity change data of the first reflected laser light, eliminate the influence of the light source intensity and the change of the optical properties of the filter in the first transmitted laser light, the second transmitted laser light, and the second reflected laser light, and calculate Multiple sets of laser intensity change data that are only affected by the concentration of the sample on the front side of the filter membrane.

The present invention has the following beneficial effects:

1. In the laser detection device provided by the embodiment of the present invention, since the first laser emitter is arranged on the back side of the filter membrane, part of the emitted laser light passes through the filter membrane to form the first transmitted laser light, and part of it is reflected by the filter membrane to form the first reflected laser light , according to the intensity change of the first reflected laser, the influence caused by the change of the light source intensity and the optical properties of the filter membrane in the first transmitted laser can be effectively eliminated in real time, and the laser intensity change data only affected by the sample concentration on the front of the filter membrane can be calculated. In order to accurately judge the change of the concentration of the sample on the front of the filter membrane.

2. In the organic carbon element carbon analyzer provided by the embodiment of the present invention, the desorption furnace includes a sealed chamber that is arranged around the periphery of the desorption furnace tube and is isolated from the desorption furnace tube. The air is discharged, so that the sealed chamber is in an oxygen-free or low-oxygen space, and the heating device of the desorption furnace is heated in an oxygen-free or low-oxygen space, thereby preventing the heating device of the desorption furnace from being oxidized at high temperature, thereby improving the service life of the heating device of the desorption furnace . In the cooling stage, the rapid cooling of the analysis furnace tube can be realized by introducing the protective gas into the sealed chamber, so that the filter membrane can quickly meet the temperature requirements of the next batch of sample detection. Improve heat dissipation efficiency, reduce noise and vibration during equipment operation, ensure operation stability, and effectively protect the heating device of the desorption furnace, which greatly prolongs the life of the heating device of the desorption furnace.

In addition to the objects, features and advantages described above, the present invention has other objects, features and advantages. Hereinafter, the present invention will be described in further detail with reference to the drawings.

Description of drawings

The accompanying drawings constituting a part of this application are used to provide further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 is a schematic structural diagram of a laser detection device provided by an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a laser detection device provided by another embodiment of the present invention;

Fig. 3 is the structural representation of the organic carbon element carbon analyzer provided by an embodiment of the present invention;

Fig. 4 is the structural representation of the organic carbon element carbon analyzer provided by another embodiment of the present invention;

5 is a step diagram of a laser detection method provided by an embodiment of the present invention;

Fig. 6 is a step diagram of a laser detection method provided by another embodiment of the present invention.

illustration:

1000. Organic carbon carbon analyzer; 1. Intake valve group; 11. First gas pipeline; 12. Second gas pipeline; 2. Desorption furnace; 21. Desorption furnace tube; 22. Desorption furnace heating wire; 23. Filter membrane; 24. Sealed cavity; 3. Analysis pipeline; 4. Oxidation furnace; 41. Oxidation furnace tube; 42. Oxidation furnace heating wire; 43. Connecting pipeline; 5. Detector; 51. Detection solenoid valve; 6 , power pump; 7, exhaust solenoid valve; 71, first exhaust pipe; 72, second exhaust pipe; 8, laser detection device; 81, laser emitter; 811, first laser emitter; 812, the first Two laser emitters; 82, the first laser detector; 83, the second laser detector; 84, the first beam splitter; 85, the second beam splitter.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in various ways defined and covered below.

As shown in FIG. 1 , an embodiment of the present invention provides a laser detection device 8 for setting in an organic carbon elemental carbon analyzer 1000 to realize the segmentation of organic carbon and elemental carbon. The laser detection device 8 includes a laser emitter 81 , a first laser detector 82 and a second laser detector 83, the laser emitter 81 is used to emit laser light toward the filter membrane 23, and part of the emitted laser light passes through the filter membrane 23 to form a transmitted laser light , part of which is reflected by the filter membrane 23 to form reflected laser light. The first laser detector 82 and the second laser detector 83 are respectively arranged on opposite sides of the filter membrane 23 and are used to receive the transmitted laser light and the laser beam respectively. reflected laser light.

Preferably, the laser emitter 81 includes a first laser emitter 811 disposed on the back side of the filter membrane 23, and part of the laser light emitted by the first laser emitter 811 towards the filter membrane 23 passes through The filter film 23 forms the first transmitted laser light, and part of it is reflected by the filter film 23 to form the first reflected laser light. The first laser detector 82 is arranged on the front side of the filter film 23 and is used to receive the first laser light. To transmit laser light, the second laser detector 83 is arranged on the back side of the filter membrane 23 and used to receive the first reflected laser light. Because the air sample containing particulate matter passes through the filter membrane 23, the filter membrane 23 can trap the particulate matter in the air sample on the front of the filter membrane 23, and a small part penetrates into the shallow layer of the filter membrane 23 and In the middle, when the filter membrane 23 reaches a certain thickness, the filter membrane 23 can completely trap the particulate matter on its front side, and does not exist on the back side of the filter membrane 23 . Therefore, the intensity of the first transmitted laser light that penetrates to the front of the filter membrane 23 from the back side of the filter membrane 23 is affected by the intensity of the light source, the optical properties of the filter membrane and the concentration of cracked carbon/elemental carbon, and from the filter membrane 23 The intensity of the first reflected laser directly reflected back from the back is only affected by the intensity of the light source and the optical properties of the filter.

Secondly, during the anaerobic pyrolysis of organic carbon by the organic carbon elemental carbon analyzer 1000, part of the organic carbon will be converted into cracked carbon (which is considered to have the same light absorption coefficient as the original elemental carbon) attached to the The surface of the filter membrane 23, at this time, the first transmitted laser light is weakened with the increase of the concentration of elemental carbon, and in the process of the oxidation and pyrolysis of elemental carbon by the organic carbon elemental carbon analyzer 1000, with the increase of the elemental carbon concentration, the As the carbon concentration gradually decreases, the first transmitted laser light gradually increases, when the intensity of the first transmitted laser light increases to the intensity before the pyrolysis of the organic carbon (it is considered that the cracked carbon is prior to the oxidation of the elemental carbon that originally existed Decomposition), the node can be judged as the node of the initial elemental carbon concentration, that is, the elemental carbon converted from organic carbon has been completely pyrolyzed at this time, so as to realize the division of organic carbon and elemental carbon.

Therefore, according to the intensity change of the first reflected laser light, the influence produced by the change of the light source intensity and the optical properties of the filter film in the first transmitted laser light can be eliminated, so that the first transmitted laser light is only affected by cracked carbon and elemental carbon. In order to accurately divide the organic carbon and elemental carbon, so as to realize the accurate measurement of organic carbon and elemental carbon content. In other words, the back-reflected light is used as the reference light to track and correct the transmitted light intensity in real time, that is, the influence of the light source intensity fluctuation on the transmitted light intensity is corrected, and the influence of the optical property change caused by the temperature change of the filter film on the transmitted light intensity is also corrected. Influence, this optical path can be applied in the measurement of organic carbon and elemental carbon by thermo-optic transmission method, and realize the accurate segmentation of organic carbon and elemental carbon, thereby improving the detection accuracy of organic carbon and elemental carbon.

In addition, when using the optical method to measure the content of elemental carbon, this optical path can realize the accurate determination of elemental carbon, eliminate the influence of other factors on the transmitted light intensity, and improve the accuracy of elemental carbon measurement.

It should be understood that the flow paths of gases such as samples and carrier gases are along the front side of the filter membrane 23 and permeate through the back side of the filter membrane 23, that is, the front side of the filter membrane 23 is the side for filtering and collecting particulate matter , the back side of the filter membrane 23 is the side for seeping out gas.

Further, the laser detection device 8 also includes a first beam splitter 84 arranged at the front end of the first laser emitter 811, and the first beam splitter 84 is inclined at an angle of 45 degrees relative to the surface of the filter membrane 23 , the light output direction of the first laser emitter 811 is perpendicular to the surface of the filter film 23, the light input direction of the second laser detector 83 is parallel to the surface of the filter film 23, and the first laser emitter 811 At least part of the emitted laser light passes through the first beam splitter 84 and illuminates the filter film 23, and the first reflected laser light can be reflected by the first beam splitter 84 and then enter the second laser for detection The device 83 separates the emitted light and reflected light through the first beam splitter 84 .

In other embodiments, when the first laser emitter 811 cannot emit laser light toward the filter membrane 23 in a direction perpendicular to the surface of the filter membrane 23 due to the structure and position constraints of itself or other components, the The light output direction of the first laser emitter 811 can also be set at other angles relative to the surface of the filter film 23, and it is only necessary to ensure that the light output direction of the first laser emitter 811 faces the filter film 23 to form the The first transmitted laser light and the first reflected laser light are described above. In the same way, it is enough to ensure that the light incident direction of the second laser detector 83 is staggered from the filter film 23, and the angle of inclination of the first beam splitter 84 relative to the surface of the filter film 23 follows the first reflected laser light and the filter film 23. The incident direction of the second laser detector 83 is changed, so that the first reflected laser light can enter the second laser detector 83 after being reflected by the first beam splitter 84 and changing an angle.

It should be understood that this embodiment takes the organic carbon element carbon analyzer 1000 as an example to illustrate the structure and operating principle of the laser detection device 8, but it cannot be regarded as a limitation on the scope of use of the laser detection device 8, that is, The laser detection device 8 is not limited to optically correcting the concentration detection of organic carbon and elemental carbon to determine the division point of organic carbon and elemental carbon, and can also be used to detect the concentration of elemental carbon, which can also be set in other Real-time detection of other sample concentrations on the filter membrane in a type of detection device.

Please refer to FIG. 5, this embodiment also provides a laser detection method using the above-mentioned laser detection device 8 for detection, and the laser detection method includes the following steps:

Step S100: emit laser light toward the back of the filter membrane 23 through the first laser emitter 811, and make the laser emitted by the first laser emitter 811 partly pass through the front of the filter membrane 23 to form a first transmitted laser light, Part of it is reflected back by the back of the filter membrane 23 to form the first reflected laser light.

Since the intensity of the light source may fluctuate and drift during the use of the laser emitter, and the optical properties of the filter film 23 will change with the temperature of the analytical furnace 2, resulting in the first transmitted laser and the The intensity of the first reflected laser light is affected by the intensity of the light source and the optical properties of the filter, resulting in that the intensity change data of the first transmitted laser light cannot accurately reflect the concentration conversion process of organic carbon and elemental carbon, so that organic carbon, elemental carbon The segmentation point of the sample changes, and accurate segmentation cannot be performed, which affects the accurate measurement of the concentration of organic carbon and elemental carbon.

At this time, the first laser emitter 811 is arranged on the back side of the filter membrane 23, and the filter membrane 23 retains the particles at the front position, and the particles containing organic carbon and elemental carbon do not exist in the filter membrane 23. The back of the filter membrane 23. Therefore, when the back side of the filter membrane 23 is irradiated by the first laser emitter 811, the intensity of the first transmitted laser light will be affected by the intensity of the light source, the optical properties of the filter membrane and the sample concentration on the front side of the filter membrane, and from the The first reflected laser light reflected from the back of the filter membrane 23 is only affected by the intensity of the light source and the optical properties of the filter membrane.

Step S200 : receiving the first transmitted laser light through the first laser detector 82 and receiving the first reflected laser light through the second laser detector 83 .

The light incident direction of the first laser detector 82 faces the filter film 23, the first transmitted laser light directly enters the first laser detector 82 and is detected by it, and the incident laser light of the second laser detector 83 The light direction deviates from the filter film 23 , and the first reflected laser light is reflected by the first beam splitter 84 and changes direction, then enters the second laser detector 83 and is detected by it.

Step S300: According to the intensity change data of the first reflected laser, eliminate the influence of the light source intensity and the change of the optical properties of the filter in the first transmitted laser, and calculate the value that is only affected by the concentration of the sample on the front side of the filter. Laser intensity variation data.

Since the intensity of the first transmitted laser light is affected by the intensity of the light source, the optical properties of the filter membrane, and the sample concentration on the front of the filter membrane, while the first reflected laser light is only affected by the intensity of the light source and the optical properties of the filter membrane, it can be determined according to the The intensity change data of the first reflected laser light is processed one-to-one with the intensity change data of the first transmitted laser light, and the influence caused by the light source intensity and the change of the optical property of the filter film in the first transmitted laser light is eliminated, so that the The first transmitted laser light is only affected by the sample concentration on the front of the filter membrane, and the change process of the sample concentration on the front of the filter membrane 23 is accurately fed back through the laser intensity change data of the first transmitted laser. Therefore, when the laser detection method is applied to the organic carbon elemental carbon analyzer 1000, the concentration change process of organic carbon and elemental carbon can be accurately reflected, and then the organic carbon and elemental carbon on the filter membrane 23 can be accurately measured. Segmentation improves the detection accuracy of organic carbon and elemental carbon concentrations. That is to say, the first reflected laser (back reflected laser) received by the second laser detector is used as a reference light to track and correct the intensity of the first transmitted laser in real time, that is, the influence of the fluctuation of the light source intensity on the intensity of the first transmitted laser is corrected, and also The influence of the change of optical properties caused by the temperature change of the filter film on the intensity of the first transmitted laser is corrected. This optical path can be applied to the measurement of organic carbon and elemental carbon by thermo-optic transmission method, and realize the accurate division of organic carbon and elemental carbon, thereby improving The detection accuracy of organic carbon and elemental carbon is improved.

As shown in FIG. 2 , in another embodiment, the laser emitter 81 also includes a second laser emitter 812 disposed on the front side of the filter membrane 23, and the second laser emitter 812 faces the Among the laser light emitted by the filter membrane 23, part passes through the back side of the filter membrane 23 to form the second transmitted laser light and is received by the second laser detector 83, and part is directly reflected back by the front side of the filter membrane 23 to form the second transmitted laser light. The laser light is reflected and received by the first laser detector 82 .

Further, the first laser transmitter 811 and the second laser transmitter 812 have different laser modulation frequencies, and the first laser detector 82 and the second laser detector 83 are both provided with frequency demodulation The module can also distinguish and measure the lasers with different modulation frequencies through the frequency demodulation module, so that when receiving the lasers emitted by the first laser transmitter 811 and the second laser transmitter 812 at the same time, the The lasers emitted by the first laser emitter 811 and the second laser emitter 812 are distinguished, and the intensity change data of the two lasers are respectively detected.

Further, the light output direction of the second laser emitter 812 is parallel to the surface of the filter film 23, and the laser detection device 8 further includes a second beam splitter 85 arranged at the front end of the second laser emitter 812, The second beam splitter 85 is also inclined at an angle of 45 degrees relative to the surface of the filter membrane 23 . The laser light emitted by the second laser emitter 812 can be reflected by the second beam splitter 85 to change its direction and then illuminate the front side of the filter film 23 in a direction perpendicular to the surface of the filter film 23, and pass through the The second reflected laser light reflected by the filter membrane 23 can enter the first laser detector 82 after passing through the second beam splitter 85 .

In other embodiments, when the second laser emitter 812 cannot emit laser light in a direction parallel to the surface of the filter membrane 23 due to the structure and position of itself or other components, the second laser emitter 812 The light emitting direction of 812 can also be set obliquely relative to the surface of the filter membrane 23 . Correspondingly, when the light emitting direction of the second laser emitter 811 is staggered from the filter membrane 23, the angle at which the second beam splitter 84 is inclined relative to the surface of the filter membrane 23 needs to follow the direction of the second laser emitter. 811 to change the direction of light output, so that the laser light emitted by the second laser emitter 811 can be directed to the filter membrane 23 after being adjusted by the second beam splitter 84 .

Please refer to FIG. 6, when the laser detection device 8 further includes a second laser emitter 812, the laser detection method specifically includes the following steps:

Step S100: emit laser light toward the back of the filter membrane 23 through the first laser emitter 811, and let the laser light emitted by the first laser emitter 811 partly pass through the filter membrane 23 to form a first transmitted laser light, and part of the laser light is transmitted by the filter membrane 23. Film 23 reflects to form the first reflected laser light, the intensity of the first transmitted laser light is affected by the intensity of the light source, the optical properties of the filter membrane and the sample concentration on the front side of the filter membrane, and the intensity of the first reflected laser light is affected by the intensity of the light source and the optical properties of the filter membrane Impact.

While the first laser emitter 811 emits laser light, the second laser emitter 812 emits laser light toward the front of the filter membrane 23, and the laser light emitted by the second laser emitter 812 partially passes through the filter membrane 23 The second transmitted laser light is formed, and part of it is reflected by the filter membrane to form the second reflected laser light. Both the second transmitted laser light and the second reflected laser light are affected by the intensity of the light source, the optical properties of the filter membrane, and the sample concentration on the front side of the filter membrane.

Step S200: receiving the first transmitted laser light and the second reflected laser light through the first laser detector 82, and receiving the first reflected laser light and the second transmitted laser light through the second laser detector 83 laser.

Step S300: According to the intensity change data of the first reflected laser, eliminate the influence caused by the change of the light source intensity and the optical properties of the filter in the first transmitted laser, the second transmitted laser, and the second reflected laser in real time, and calculate Multiple sets of laser intensity change data that are only affected by the concentration of the sample on the front side of the filter membrane are obtained.

Firstly, according to the change in the intensity of the first reflected laser light, the second transmitted laser light and the second reflected laser light formed by the second laser emitter 812 can be corrected in real time to eliminate the changes caused by the initial light source intensity and the optical properties of the filter. The impact produced can realize the accurate segmentation of organic carbon and elemental carbon content of the two methods of thermo-optic transmission method and thermo-optic reflection method, and improve the detection accuracy. Secondly, the separation point of organic carbon and elemental carbon determined according to the intensity change of the first transmitted laser formed after the first laser emitter 811 passes through the filter membrane combined with the second transmitted laser formed by the second laser emitter 812 The segmentation point of organic carbon and elemental carbon determined by the intensity change of the laser and/or the second reflected laser realizes mutual verification between multiple segmentation points, and further improves the accuracy of organic carbon and elemental carbon content segmentation through multiple verifications and data corrections This greatly reduces the error in the segmentation of organic carbon and elemental carbon concentrations.

As shown in Figures 3 and 4, the embodiment of the present invention also provides an organic carbon elemental carbon analyzer, which is used to detect the content of organic carbon and elemental carbon in the air. There is no low-temperature area between the furnaces, which effectively avoids the adsorption loss of the desorbed gas and can provide accurate air quality data.

As shown in Figure 3, the organic carbon element carbon analyzer 1000 includes an analysis furnace 2, and the analysis furnace 2 includes an analysis furnace tube 21 and an analysis furnace heating device arranged on the analysis furnace tube 21, and is fixed on the analysis furnace tube 21. The filter membrane 23 in the analysis furnace tube 21 is described, and the filter membrane 23 is used to collect the particulate matter in the sample gas flowing through the analysis furnace tube 21, and the analysis furnace heating device can specifically be wound around the analysis furnace tube The analysis furnace heating wire 22 on the 21 is used to heat the internal space of the analysis furnace tube 21 so that the filter membrane 23 is in a high-temperature environment, so that the organic carbon or the organic carbon in the particulate matter on the surface of the filter membrane 23 Elemental carbon is pyrolyzed out.

Preferably, the organic carbon element carbon analyzer 1000 also includes the above-mentioned laser detection device 8, the first laser emitter 811 and the second laser detector 83 are arranged on the analysis furnace tube 21 corresponding to the filter membrane 23, the first laser detector 82 is set at the end of the analysis furnace tube 21 corresponding to the front of the filter membrane 23.

Since the analysis furnace 2 is in the process of pyrolyzing the particles on the surface of the filter membrane 23, the intensity change data of the transmitted laser light passing through the filter membrane 23 can feed back the change process of the sample concentration on the surface of the filter membrane 23 in real time. At this time, the first transmitted laser light and the first reflected laser light formed by the first laser emitter 811 are respectively received by the first laser detector 82 and the second laser detector 83, and the first reflected laser light can be passed through the The intensity change data of the first transmitted laser light is used as reference data, and the influence caused by the change of the light source intensity and the optical properties of the filter film in the intensity change data of the first transmitted laser light is eliminated, so that the front side of the filter film 23 can be accurately fed back through the first transmitted laser light. Data on changes in sample concentration.

As shown in Figure 4, when the laser detection device 8 also includes a second laser emitter 812, the second laser emitter 812 is located at one end of the analysis furnace tube 21 corresponding to the front of the filter membrane 23 and is used for Laser light is emitted toward the front of the filter membrane 23 to form the second transmitted laser light that penetrates to the back side of the filter membrane 23 and the second reflected laser light that is reflected back by the front of the filter membrane 23. At this time, due to the Both the second transmitted laser light and the second reflected laser light are directly irradiated on the sample on the surface of the filter membrane 23 , and the intensity change is affected by the concentration of the sample on the surface of the filter membrane 23 .

Therefore, according to the intensity change of the first reflected laser light, the influence caused by the change of the light source intensity and the optical property of the filter film in the first transmitted laser light, the second transmitted laser light, and the second reflected laser light can be eliminated, and the calculated Multiple sets of laser intensity change data that are only affected by the concentration of the sample on the front side of the filter membrane can more accurately feed back the change data of the sample concentration on the surface of the filter membrane 23 by comparing multiple sets of data.

Please refer to FIG. 3 and FIG. 4 , preferably, the desorption furnace 2 further includes a sealed cavity 24, the sealed cavity 24 surrounds the outer circumference of the desorption furnace tube 21 and forms a joint enclosure with the desorption furnace tube 21, that is An independent sealed space is formed on the outer periphery of the desorption furnace tube 21 , and the desorption furnace heating wire 22 is arranged in the sealed cavity 24 .

Further, the organic carbon carbon analyzer 1000 also includes an inlet valve group 1 and a first gas delivery pipeline 11 connected to the inlet valve group 1, and the first gas delivery pipeline 11 is connected to the sealed chamber 24 communicates and is used to introduce the protective gas output by the intake valve group 1 into the sealed cavity 24 .

Further, the organic carbon carbon analyzer 1000 also includes a power pump 6 and a first exhaust pipeline 71, one end of the first exhaust pipeline 71 is connected to the sealed chamber 24, and the other end is connected to the power pump 6, the power pump 6 is used to discharge the gas in the sealed cavity 24 along the first exhaust pipe 71.

Since the sealing chamber 24 that seals and wraps the heating wire 22 of the desorption furnace is set outside the desorption furnace tube 21, the air inlet valve group 1 can enter the sealing chamber 24 along the first gas pipeline 11 at this time. Inflate a protective gas, which can be an oxygen-free or low-oxygen gas, so that the air in the sealed cavity 24 is discharged along the first exhaust pipe 71, so that the sealed cavity 24 is in an oxygen-free or hypoxic state. Hypoxic space, so that the desorption furnace heating wire 22 is heated in an oxygen-free or hypoxic space, thereby preventing the desorption furnace heating wire 22 from being oxidized at high temperature and improving the service life of the desorption furnace heating wire 22. In addition, the sealed cavity 24 seals and wraps the heating wire 22 of the desorption furnace in a sealed space, which can play a role in gathering heat, which is beneficial to reduce the heat loss of the heating wire 22 of the desorption furnace, and improve heating efficiency and heat preservation. Effect.

In addition, since the maximum temperature of the analysis furnace 2 during analysis can reach 850° C. during the detection process, the temperature of the analysis furnace tube 21 needs to be rapidly lowered before the next sample detection, so as to avoid that In the sampling stage, the residual high temperature in the analysis furnace tube 21 directly pyrolyzes the organic carbon or elemental carbon in the sample, which affects the subsequent detection results. For this, the existing organic carbon elemental carbon analyzer usually uses a cooling fan with a large air volume Blowing to cool down the temperature, the cooling effect is not good and there is a lot of noise and vibration, which cannot guarantee the stable operation of the equipment, resulting in poor user experience and a large volume of the instrument.

In the organic carbon elemental carbon analyzer 1000 provided in this embodiment, the desorption furnace 2 includes a sealed cavity 24 surrounding the outer periphery of the desorption furnace tube 21, and a protective gas (such as nitrogen) is introduced into the sealed cavity 24 The rapid cooling of the desorption furnace tube 21 and the desorption furnace heating wire 22 can be realized inside, the temperature of the desorption furnace tube 21 can be quickly dropped from 850°C to about 400°C, and the desorption furnace tube can be 21 When the temperature drops below 400°C, air is input to the sealed chamber 24 through the air intake valve group 1 switching air path, and at the same time, the input air is quickly discharged by the power pump 6 through the first exhaust pipe 71 The sealed cavity 24, the power pump 6 preferably adopts a large flow air pump, and the flow rate can reach 80L/min without resistance, so that rapid ventilation can be realized in the sealed cavity 24, and the rapid circulation of air facilitates It can achieve the effect of rapid cooling. Thus, in the high temperature stage, oxygen-free protective gas is used for rapid cooling, which can avoid the oxidation of the heating wire 22 of the analysis furnace, and switch to the air extraction heat dissipation mode in the semi-high temperature stage to ensure that the heating wire 22 of the analysis furnace service life, while reducing the gas consumption of nitrogen and other protective gases, reducing cooling costs. Moreover, since there is no cooling fan, the volume of the organic carbon carbon analyzer 1000 is further reduced, and the noise and vibration during operation can be reduced.

Preferably, the first exhaust pipeline 71 and the first gas delivery pipeline 11 are respectively arranged on opposite sides of the sealed chamber 24, so that the protective gas output by the first gas delivery pipeline 11 first passes through the The analysis furnace heating wire 22 is discharged from the first exhaust pipe 71, that is, a gas circulation channel is naturally formed around the analysis furnace heating wire 22, so that the protective gas can surround the analysis furnace tube 21 and the analysis furnace. The heating wire 22 circulates to improve the cooling effect on the desorption furnace tube 21 when the gas circulates.

Shown in Fig. 3 and Fig. 4, described organic carbon element carbon analyzer 1000 also comprises the analysis pipe 3 that is connected with described analysis furnace tube 21 successively, oxidation furnace 4 and detector 5, through described analysis furnace 2 heat The decomposed organic carbon and elemental carbon can enter the oxidation furnace 4 along the analysis pipeline 3 for oxidation, and finally detect the carbon dioxide concentration output by the oxidation furnace 4 through the detector 5 to calculate the organic carbon and elemental carbon specific content.

Specifically, the analysis pipeline 3 and the analysis furnace tube 21 are coaxially arranged and communicated with each other, that is, the analysis pipeline 3 and the analysis furnace tube 21 are linear structures and are butted back and forth along the same line to form a straight line. gas flow channels. In other embodiments, the desorption pipeline 3 may also be formed by directly extending from the desorption furnace tube 21 .

The oxidation furnace 4 includes an oxidation furnace tube 41 sleeved on the analysis pipeline 3 and an oxidation furnace heating device arranged on the oxidation furnace tube 41. The oxidation furnace heating device is specifically wound around the oxidation furnace The oxidation furnace heating wire 42 on the outer periphery of the tube 41, the analysis furnace tube 41 includes a cavity with a certain thickness, so as to form a storage space on the outer circumference of the analysis pipeline 3, and the storage space is built with an oxidant (not shown in the figure, the same below). ). An air inlet and an air outlet are respectively provided at the two opposite ends of the oxidation furnace tube 41, and the air inlet is provided with a communication pipe 43 communicated with the analysis pipe 3, and the air outlet is connected to the detector. 5 connected. Specifically, the oxidation furnace tube 41 has a cylindrical structure and forms an annular oxidation channel with the analysis pipe 3 . Of course, the oxidation furnace tube 41 is not limited to a cylindrical structure, and the oxidation channel is not limited to a ring shape.

Further, the organic carbon carbon analyzer 1000 also includes a second gas pipeline 12, an exhaust solenoid valve 7 and a second exhaust pipeline 72, one end of the second gas pipeline 12 is connected to the inlet valve Group 1 is connected, and the other end communicates with the analysis furnace tube 21 and is used to switchably introduce gases such as atmospheric samples, anaerobic carrier gas, aerobic carrier gas, and calibration gas output by the intake valve group 1 into the analysis Inside the furnace tube 21. The exhaust solenoid valve 7 includes two input ends and an output end, and the two input ends are respectively connected to the first exhaust pipe 71 and the second exhaust pipe 72 in one-to-one correspondence, and the output end is connected to the second exhaust pipe 72 in a one-to-one manner. The power pump 6 is connected and switchably connected to one of the two input ends. So that the power pump 6 can communicate with the first exhaust pipe 71 or communicate with the second exhaust pipe 72 under the control of the exhaust solenoid valve 7, so that one power pump 6 can The gas in the sealed cavity 24 or the gas in the desorption furnace 2, desorption pipeline 3 and oxidation furnace 4 can be flexibly switched to simplify the structure and reduce the cost, and realize the function of exhausting and controlling the gas flow.

The specific detection process of the organic carbon element carbon analyzer 1000 includes: inputting an atmospheric sample containing particulate matter into the desorption furnace tube 21 through the inlet valve group 1 along the second gas pipeline 12, so that the sample gas The particulate matter is filtered and collected by the filter membrane 23 in the desorption furnace tube 21, and the particulate matter is attached to the surface of the filter membrane 23 at this time. Then, through the inlet valve group 1 and along the second gas pipeline 12, an oxygen-free carrier gas is input into the desorption furnace tube 21. Specifically, helium can be used as the oxygen-free carrier gas, so that the desorption furnace The gas in the tube 21 is completely replaced to form an oxygen-free environment, so that the filter membrane 23 is in an oxygen-free environment. At this time, the temperature of the analysis furnace 21 is gradually raised by the heating wire 22 of the analysis furnace, so that the filter membrane 23 is in an oxygen-free environment. Most of the organic carbon on the surface of the membrane 23 is released by pyrolysis (a small part of the organic carbon is converted into elemental carbon and continues to adhere to the surface of the filter membrane 23), and the resolved organic carbon gas enters the oxidation gas through the analysis pipeline 3. In the furnace tube 41, through the continuous heating of the oxidation furnace heating wire 42 and the chemical reaction of the oxidant, the organic carbon gas is oxidized by the oxidation furnace 4 and converted into carbon dioxide, which can be detected by the detector 5 , to judge the organic carbon content in the sample. After all the analysis of the organic carbon in the sample is completed, the aerobic carrier gas is input to the analysis furnace tube 21 along the second gas pipeline 12 through the inlet valve group 1, and the aerobic carrier gas can be specifically used Helium-oxygen mixed gas to completely replace the gas in the analysis furnace tube 21 to form an aerobic environment, so that the filter membrane 23 is in an aerobic environment, and now continue to pass through the analysis furnace heating wire 22 to the described The analysis furnace 21 heats up step by step, so that the elemental carbon on the surface of the filter membrane 23 is pyrolyzed and escaped, and the analyzed elemental carbon gas enters the oxidation furnace tube 41 through the analysis pipeline 3, and passes through the oxidation furnace heating wire Under the continuous heating at 42 and the chemical reaction of the oxidant, the elemental carbon gas is oxidized by the oxidation furnace 4 and converted into carbon dioxide, which can be detected by the detector 5 to determine the elemental carbon content in the sample. During the whole process, there is at least one laser beam hitting the filter membrane 23, and the transmitted light (or reflected light) formed by the filter membrane 23 will be weakened when the organic carbon is carbonized. As the oxygen-free carrier gas is switched to an oxygen carrier gas, and the temperature rises, the elemental carbon will be oxidized and decomposed, and the light intensity of the transmitted light (or reflected light) of the laser beam will gradually increase. When it returns to the original transmission ( or reflected) light intensity, this moment is considered as the separation point of organic carbon and elemental carbon, that is, all carbon detected before this moment is considered as organic carbon, and all carbon detected after this time is considered as elemental carbon. The integrated optics method corrects for the cracked carbon (thought to have the same light absorption coefficient as the native elemental carbon) generated during the elevated temperature analysis of the organic carbon.

Further, in order to ensure the accuracy of the detection results, after the detection of the elemental carbon content is completed, the calibration gas can also be input into the desorption furnace tube 21 through the inlet valve group 1 along the second gas pipeline 12, the The calibration gas can specifically be methane gas, which can directly pass through the filter membrane 23 into the oxidation furnace tube 41, and be detected by the detector 5 after being oxidized by the oxidation furnace 41. According to the detector 5 Compare the detection result of the calibration gas with the standard carbon content in the calibration gas, calculate the detection error of the organic carbon elemental carbon analyzer 1000, and then compare the organic carbon and elemental carbon by the detection error The test results are calibrated to obtain more accurate test data.

Further, the organic carbon carbon analyzer 1000 also includes a detection solenoid valve 51 arranged between the detector 5 and the oxidation furnace tube 41, and the detection solenoid valve 51 is opened and closed to control the detection The detection time of device 5 is used to ensure the accuracy of the detection results.

It is worth noting that since the oxidation furnace 4 is arranged around the periphery of the analysis pipeline 3, the temperature of the oxidation furnace 4 itself realizes the heating and heat preservation effect on the analysis pipeline 3, so that the analysis furnace 2 and The overall gas path between the oxidation furnaces 4 is in a high-temperature state, avoiding the existence of low-temperature regions in the analysis pipeline 3, greatly weakening the adsorption capacity of the analysis pipeline 3 to the analysis gas, thereby reducing the loss of the sample during the transfer process. Loss, improve the accuracy of the test results. Secondly, this structure can also effectively reduce the distance between the oxidation furnace 4 and the analysis furnace 2, so that the overall structure of the organic carbon element carbon analyzer 1000 is more compact, which is convenient for realizing miniaturization design, and has a higher Strong, not easy to damage.

Preferably, the air inlet is located at the end of the oxidation furnace tube 41 away from the desorption furnace 2, that is, the oxidation furnace tube 41 is connected to the end of the desorption pipeline 3 away from the desorption furnace 2, so as to avoid The gas in the end of the analysis pipeline 3 far away from the analysis furnace 2 has retained samples to avoid excessive dead volume, so that the pyrolysis gas in the analysis pipeline 3 can basically be transferred to the oxidation furnace tube 41 , to ensure the accuracy of the test sample.

Further, the organic carbon element carbon analyzer 1000 also includes a heat insulation layer (not shown in the figure, the same below) arranged between the analysis furnace 2 and the oxidation furnace 4, and the heat insulation layer can be made of thermal insulation cotton Made of heat insulating materials, so as to avoid the high temperature of the oxidation furnace 4 itself from affecting the temperature of the desorption furnace 2, and ensure the temperature control effect of the desorption furnace 2.

To sum up, the organic carbon elemental carbon analyzer 1000 provided by the embodiment of the present invention has strong stability, reliability, long service life, can realize miniaturization design, can accurately find the segmentation point of organic carbon and elemental carbon, and the detection results Accurate and reliable.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

A laser detection device, comprising a laser emitter (81), a first laser detector (82) and a second laser detector (83), the laser emitter (81) is used to emit laser light towards the filter membrane (23) , the first laser detector (82) and the second laser detector (83) are respectively used to receive the transmitted laser light passing through the filter membrane (23) and the reflected laser light reflected by the filter membrane (23), It is characterized in that the laser emitter (81) includes a first laser emitter (811) arranged on the back side of the filter membrane (23), and the first laser emitter (811) faces the filter membrane (23) Among the emitted laser light, part passes through the filter film (23) to form the first transmitted laser light, and part is reflected by the filter film (23) to form the first reflected laser light, and the first laser detector (82) It is arranged on the front side of the filter membrane (23) and is used to receive the first transmitted laser light, and the second laser detector (83) is arranged on the back side of the filter membrane (23) and is used to receive the first A reflected laser.
The laser detection device according to claim 1, characterized in that, the laser emitter (81) also includes a second laser emitter (812) arranged on the front side of the filter membrane (23), the first laser emitter (812) Among the laser light emitted by the two laser emitters (812) toward the filter membrane (23), part passes through the filter membrane (23) to form a second transmitted laser light and is received by the second laser detector (83), and part The second reflected laser light is formed by being reflected by the filter membrane (23) and received by the first laser detector (82).
The laser detection device according to claim 2, characterized in that, the laser modulation frequencies of the first laser emitter (811) and the second laser emitter (812) are different, and the first laser detector ( 82) and the second laser detector (83) are both equipped with a frequency demodulation module, and the laser light with different modulation frequencies can be differentiated and measured through the frequency demodulation module.
The laser detection device according to claim 2, characterized in that, the laser detection device further comprises a first beam splitter (84) arranged at the front end of the first laser emitter (811) and a first beam splitter (84) arranged at the second The second light splitter (85) at the front end of the laser emitter (812), the first light splitter (84) and the second light splitter (85) are all inclined relative to the surface of the filter (23);

The light emitting direction of one of the first laser emitter (811) and the second laser emitter (812) is towards the filter membrane (23), and at least part of the emitted laser light passes through it The beam splitter at the front end illuminates the filter membrane (23); the light exit direction of the other laser transmitter staggers the filter membrane (23), and at least part of the laser emitted is reflected by the beam splitter at the front end and shines on the filter membrane (23). The filter membrane (23).
The laser detection device according to claim 1, characterized in that, the laser detection device further comprises a first beam splitter (84) arranged at the front end of the first laser emitter (811), the first beam splitter (84) inclined relative to the surface of the filter (23), the light output direction of the first laser emitter (811) faces the filter (23), and the incident light of the second laser detector (83) The direction staggers the filter membrane (23), at least part of the laser light emitted by the first laser emitter (811) passes through the first beam splitter (84) and illuminates the filter membrane (23), and the The first reflected laser light can enter the second laser detector (83) after being reflected by the first beam splitter (84) and changing its direction.
A kind of organic carbon element carbon analyzer, comprises analysis furnace (2), and described analysis furnace (2) comprises analysis furnace tube (21) and is located at the filter membrane (23) in described analysis furnace tube (21), and The desorption furnace heating device arranged on the desorption furnace tube (21), the filter membrane (23) is used to collect the particulate matter in the sample gas flowing through the desorption furnace tube (21), it is characterized in that the The organic carbon element carbon analyzer also includes the laser detection device as claimed in claim 1, and the first laser emitter (811) and the second laser detector (83) are arranged on the analysis furnace tube (21) Corresponding to one end of the back of the filter membrane (23), the first laser detector (82) is arranged at one end of the analysis furnace tube (21) corresponding to the front of the filter membrane (23).
The organic carbon element carbon analyzer according to claim 6, characterized in that, the desorption furnace (2) also includes a set around the outer circumference of the desorption furnace tube (21) and surrounds the desorption furnace tube (21) The sealing cavity (24) that forms together, described analytical furnace heating device is arranged in the described sealing cavity (24);

The organic carbon carbon analyzer also includes an intake valve group (1) and a first gas pipeline (11) connected to the gas inlet valve group (1), and the first gas pipeline (11) is connected with the gas inlet valve group (1). The sealing cavity (24) communicates and is used for introducing the protective gas output by the intake valve group (1) into the sealing cavity (24).
The organic carbon carbon analyzer according to claim 7, characterized in that, the organic carbon carbon analyzer also includes a power pump (6) and a first exhaust pipe (71), and the first exhaust pipe (71) and the first gas delivery pipeline (11) are separately located on opposite sides of the sealed cavity (24), and the end of the first exhaust pipeline (71) away from the sealed cavity (24) is connected to the sealed cavity (24). The power pump (6) is connected, and the power pump (6) is used to discharge the gas in the sealed cavity (24).
A laser detection method, characterized in that, the laser detection device as claimed in claim 1 is used for detection, and the laser detection method comprises the following steps:

S100: Use the first laser emitter (811) to emit laser light toward the back of the filter membrane (23), and make the laser light emitted by the first laser emitter (811) partly pass through the filter membrane (23) to form a first transmission Laser light is partially reflected by the filter membrane (23) to form the first reflected laser light, the intensity of the first transmitted laser light is affected by the intensity of the light source, the optical properties of the filter membrane and the sample concentration on the front side of the filter membrane, the first reflected laser light The intensity is affected by the intensity of the light source and the optical properties of the filter;

S200: Receive the first transmitted laser light through a first laser detector (82), and receive the first reflected laser light through a second laser detector (83);

S300: According to the intensity change data of the first reflected laser light, eliminate the influence of the light source intensity and the change of the optical properties of the filter film in the first transmitted laser light, and calculate the laser light only affected by the concentration of the sample on the front side of the filter film Intensity change data.
The laser detection method according to claim 9, wherein when the laser detection device further includes a second laser emitter, the laser detection method comprises the following steps:

S100: Use the first laser emitter (811) to emit laser light toward the back of the filter membrane (23), and make the laser light emitted by the first laser emitter (811) partly pass through the filter membrane (23) to form a first transmission Laser light is partially reflected by the filter membrane (23) to form the first reflected laser light, the intensity of the first transmitted laser light is affected by the intensity of the light source, the optical properties of the filter membrane and the sample concentration on the front side of the filter membrane, the first reflected laser light The intensity is affected by the intensity of the light source and the optical properties of the filter;

emit laser light towards the front of the filter membrane (23) through the second laser emitter (812), and make the laser light emitted by the second laser emitter (812) partly pass through the filter membrane (23) to form a second transmitted laser light, Part of it is reflected by the filter membrane (23) to form a second reflected laser, and both the second transmitted laser and the second reflected laser are affected by the intensity of the light source, the optical properties of the filter and the concentration of the sample on the front side of the filter;

S200: Receive the first transmitted laser light and the second reflected laser light through the first laser detector (82), and receive the first reflected laser light and the second reflected laser light through the second laser detector (83) second transmitted laser light;

S300: According to the intensity change data of the first reflected laser light, eliminate the influence of the light source intensity and the change of the optical properties of the filter in the first transmitted laser light, the second transmitted laser light, and the second reflected laser light, and calculate Multiple sets of laser intensity change data that are only affected by the concentration of the sample on the front side of the filter membrane.