A gas path structure for a dust concentration laser measuring instrument

Abstract

This utility model belongs to the field of dust measurement technology, and relates to the air path structure of a dust concentration laser measuring instrument. Its air intake module has an air inlet for introducing the air to be measured; the air pump has an air intake port and an air exhaust port; the laser detection chamber has an air inlet end and an air outlet end, the air inlet end being connected to the air intake module, and the air outlet end being connected to the air pump's air intake port; a dust collection component is disposed in the air path between the air outlet end of the laser detection chamber and the air pump's air intake port, and the dust collection component contains a filter membrane box; the exhaust channel is connected to the air pump's exhaust port for discharging the air output by the air pump. This utility model achieves stable air intake and improves the measurement accuracy of dust concentration by optimizing the air path structure and module integration.

Description

Technical Field

[0001] This utility model relates to the field of dust measurement technology, specifically to the gas path structure of a dust concentration laser measuring instrument. Background Technology

[0002] In fields such as occupational health monitoring, environmental quality testing, and industrial production process control, accurate measurement of airborne dust concentration is essential to protect human health, assess environmental quality, and control production processes. Existing dust laser measuring instruments typically calculate dust concentration by detecting the number of dust particles passing through a sensor within a certain time period. These instruments usually require an external fan to control the speed of dust movement. When the dust movement speed is constant, the number of particles within a constant time period correlates with the dust mass concentration. Combining this with the intensity of the scattered light signal generated by laser irradiation of the dust, the dust concentration can be calculated.

[0003] However, existing dust laser measuring instruments suffer from poor airflow stability and low measurement accuracy. These instruments rely on external fans to control airflow, and the fan speed is susceptible to voltage fluctuations, dust blockages, and environmental airflow interference, leading to instability in the amount of air passing through the instrument's internal detection area within a constant timeframe. Since dust concentration calculations are based on particle counts under constant airflow, fluctuations in airflow directly cause particle count deviations, ultimately resulting in inaccurate measurement results and failing to meet the demands of high-precision detection.

[0004] Therefore, there is an urgent need for a laser dust concentration measuring instrument that can solve the problem of unstable air intake mentioned above, so as to improve the measurement accuracy.

[0005] Furthermore, existing dust laser measuring instruments suffer from internal dust accumulation, resulting in short instrument lifespan and susceptibility to failure. During long-term operation, airborne dust easily accumulates in the internal air passages (such as the inner walls of pipes) and the laser detection chamber (such as around the laser emitting component and the optical signal receiving component). Accumulated dust not only wears down air passage components and clogs pipes, but also obstructs the laser beam path, interferes with the reception of scattered light signals, leading to decreased sensor sensitivity and even causing overall instrument failure, significantly shortening the instrument's lifespan.

[0006] On the other hand, existing instruments require additional external fans and dispersed air paths, filters, and detection modules. The dispersed layout of each component and the complex connection structure result in an overall large instrument size, making it difficult to meet the portable use requirements of scenarios such as rapid on-site monitoring and mobile detection, thus limiting the instrument's applicability. Utility Model Content

[0007] The purpose of this invention is to overcome the defect of unstable air intake in existing dust concentration laser measuring instruments, and to provide an air path structure for a dust concentration laser measuring instrument. By optimizing the air path structure and module integration, stable air intake can be achieved.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A gas path structure for a dust concentration laser measuring instrument includes: An air intake module, wherein the air intake module is provided with an air intake port for introducing the air to be detected; An air pump having an air intake port and an air exhaust port; A laser detection chamber, the laser detection chamber having an air inlet and an air outlet, the air inlet being connected to the air inlet module, and the air outlet being connected to the air pump's suction port; A dust collection assembly is provided in the air path between the air outlet of the laser detection chamber and the air intake of the air pump, and a filter membrane box is provided inside the dust collection assembly. An exhaust passage is provided, which is connected to the exhaust port of the air pump and is used to discharge the air output by the air pump.

[0009] Furthermore, to prevent dust accumulation inside the instrument and achieve self-cleaning, the gas path structure of the dust concentration laser measuring instrument also includes a solenoid valve, a backflush filter module, and a backflush air path. The solenoid valve has a normally open inlet and a normally open outlet. The normally open inlet is connected to the outlet of the air pump, and the normally open outlet is connected to the delivery pipeline. The other end of the delivery pipeline is connected to the exhaust channel and the backflush air path. The backflush filter module is located on the backflush air path. The end of the backflush air path away from the solenoid valve is connected to the laser detection chamber. The end of the exhaust channel is provided with a sealable material. When the sealable material blocks the exhaust channel, a backflush airflow channel is formed from the air pump outlet through the solenoid valve, the delivery pipeline, and the backflush filter module to the laser detection chamber.

[0010] Furthermore, to enhance the self-cleaning effect and ensure that all areas inside the laser detection chamber prone to dust accumulation can be cleaned, the return air path includes at least two branch air channels, with the air outlet of each branch air channel corresponding to the area inside the laser detection chamber prone to dust accumulation.

[0011] Furthermore, to achieve zero-point calibration of the instrument and ensure the accuracy of the measurement benchmark, the gas path structure of the dust concentration laser measuring instrument also includes a zero-point calibration filter module and a calibration circulation gas path; one end of the calibration circulation gas path is connected to a solenoid valve, and the other end is connected to the air inlet of the laser detection chamber; the zero-point calibration filter module is set on the calibration circulation gas path; the exhaust channel is provided with a sealable material, and when the sealable material blocks the exhaust path, a closed circulation gas path is formed from the air pump exhaust port through the solenoid valve, the delivery pipe, the zero-point calibration filter module, the laser detection chamber, the dust collection assembly to the air pump extraction port.

[0012] Furthermore, to facilitate the operation of sealing and opening the exhaust passage, the sealing material is a removable sealing plug, which is adapted to the outlet end of the exhaust passage.

[0013] Furthermore, to optimize the connection structure between the exhaust channel and the return air path and ensure stable airflow switching, the solenoid valve is provided with a normally open exhaust port connected to the delivery pipeline. The end of the delivery pipeline is connected to both the exhaust channel and the return air path via a T-junction. The solenoid valve controls the flow of air in the delivery pipeline by controlling the normally open exhaust port to connect to the normally open air inlet.

[0014] Furthermore, to achieve on / off control of the calibration circulation air path, the solenoid valve is also provided with a calibration exhaust port. The exhaust port of the air pump is connected to the calibration circulation air path through the calibration exhaust port of the solenoid valve. The solenoid valve controls the conduction of the calibration circulation air path by controlling the calibration exhaust port to connect to the normally open air inlet.

[0015] Furthermore, to achieve stable connection between the air intake module and the laser detection chamber, and between the zero-point calibration filter module and the air intake module, an air intake pipe is provided between the air intake end of the laser detection chamber and the air inlet, and the air intake pipe is used to connect the air inlet and the laser detection chamber; the zero-point calibration filter module is connected to the air intake pipe through a ventilation pipe.

[0016] Furthermore, to facilitate the maintenance and replacement of the zero-point calibration filter module and ensure the filtration effect, the zero-point calibration filter module is detachably connected to the calibration circulation gas path.

[0017] Furthermore, to facilitate the maintenance and replacement of the backflush filter module and ensure the cleanliness of the backflush airflow, the backflush filter module and the backflush air path are detachably connected.

[0018] The beneficial effects of this utility model are as follows: This invention uses an air pump to replace the existing external fan, providing stable air extraction power and ensuring a constant airflow through the laser detection chamber. This avoids particle counting deviations caused by airflow fluctuations and significantly improves the accuracy of dust concentration measurement.

[0019] This invention features a back-blowing filter module and a back-blowing air path, which form a self-cleaning cycle controlled by a solenoid valve. The clean airflow can accurately sweep the laser detection chamber and areas prone to dust accumulation within the air path, solving the problem of internal dust accumulation and extending the instrument's lifespan.

[0020] This invention features a zero-point calibration filter module and a calibration circulation gas path, which can periodically calibrate the measurement benchmark and further ensure measurement accuracy.

[0021] This invention also integrates an air pump, laser detection chamber, solenoid valve, and filter module into one unit. All components are connected through an integrated air circuit, eliminating the need for external fans and separate modules, thus solving the problem of poor portability and making it suitable for on-site mobile detection scenarios. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the external structure of a dust concentration laser measuring instrument; Figure 2 This is a schematic diagram of the internal structure of a dust concentration laser measuring instrument; Figure 3 This is a perspective view of the gas path structure illustrating the normal measurement process in Example 1; Figure 4 This is a perspective view of the air path structure illustrating the self-cleaning process in Example 2; Figure 5 This is a schematic diagram illustrating the structure of the zero-point calibration filter module in Example 3.

[0023] In the diagram: 1. Intake module; 11. Intake port; 12. Intake pipe; 2. Air pump; 21. Suction port; 22. Exhaust port; 3. Laser detection chamber; 31. Exhaust end; 4. Air path module; 41. Delivery pipe; 42. Exhaust pipe; 43. Sealable material; 44. Return pipe; 45. T-junction; 46. Exhaust passage; 5. Dust collection assembly; 51. Exhaust port; 6. Solenoid valve; 61. Normally open intake port; 62. Normally open exhaust port; 63. Calibration exhaust port; 7. Backflush filter module; 8. Backflush air path; 81. Branch air path; 9. Zero-point calibration filter module; 10. Ventilation pipe; 100. Measuring instrument housing. Detailed Implementation

[0024] Example 1 like Figures 1 to 5 As shown, the dust concentration laser measuring instrument and its gas path structure of this utility model are described in detail.

[0025] The appearance of the dust concentration laser measuring instrument is shown in the attached figure. Figure 1 As shown, the measuring instrument includes a housing 100, with a display screen mounted on the front panel of the housing 100; an air intake module 1 is mounted on the top of the housing 100; electrical interfaces such as a power socket and a USB interface are provided on its side, and a power module is installed inside to supply power to various electrical components; an exhaust port is also provided on its side wall, and a sealing plug or other sealable material is detachably installed inside the exhaust port. When the sealable material is removed, the airflow being detected is discharged from the exhaust port.

[0026] like Figure 2 As shown, the measuring instrument housing 100 contains a laser detection chamber 3, an air circuit module 4, and an air pump 2.

[0027] The laser detection chamber 3 is located above the gas path module 4. The air intake module 1 is installed on the top of the laser detection chamber 3 and is connected to the laser detection chamber 3.

[0028] like Figure 3 As shown, the laser detection chamber 3 has an air inlet and an air outlet 31 at its top and bottom, respectively. The air inlet module 1 is provided with an air inlet 11 for introducing the air to be tested. The air inlet 11 is sealed by a cover, which is opened when air needs to be introduced. An air inlet pipe 12 is provided between the air inlet of the laser detection chamber 3 and the air inlet 11 of the air inlet module 1. The air inlet pipe 12 is used to stably connect the air inlet module 1 and the laser detection chamber 3, ensuring that the air to be tested enters the laser detection chamber 3 smoothly.

[0029] Laser detection of dust is an existing technology. Its working principle is as follows: The laser detection chamber 3 contains a laser emitting component (such as a semiconductor laser emitter), a focusing component (such as a concave lens), and an optical signal conversion component (such as a photoelectric sensor). The laser emitting component emits a laser beam into the chamber. Dust particles in the air being detected are irradiated by the laser, generating scattered light. The focusing component concentrates the scattered light onto the optical signal conversion component, which converts the scattered light signal into an electrical signal. This electrical signal is then received and processed by an external processing module (such as an MCU) to calculate the dust concentration. This application does not improve the laser detection module itself.

[0030] The air path module 4 houses a detachable dust collection assembly 5, a back-blowing filter module 7 (depending on requirements), and a zero-point calibration filter module 9 (depending on requirements). The dust collection assembly 5 is connected to the air path between the air outlet 31 of the laser detection chamber 3 and the air intake 21 of the air pump 2. The dust collection assembly 5 has a filter membrane box inside, in which a filter membrane can be fixed. The filter membrane box is a known technology. Figure 3 , Figure 4 The dust collection component 5 in the design conceals the partial external structure of the component to reveal the internal filter membrane box.

[0031] The air outlet 31 of the laser detection chamber 3 is connected to the air inlet of the dust collection assembly 5. After the air to be tested passes through the laser detection chamber 3, it enters the filter membrane box, where dust particles are captured by the filter membrane, thus collecting the dust and preventing dust from entering the air pump 2 and causing wear. The filter membrane box of the dust collection assembly 5 can be removed from the housing of the air path module 4 for easy replacement of the filter membrane.

[0032] Air pump 2 is connected to air circuit module 4. (For example...) Figure 3 and Figure 4 As shown, specifically, the air pump 2, as a stable power source for air extraction, has an air intake port 21 and an exhaust port 22. The air intake port 21 is connected to the air outlet 51 of the dust collection assembly 5 via a Z-shaped pipe, and the exhaust port 22 is connected to the solenoid valve 6 via a return pipe 44. Compared to the external fan used in the prior art, the air pump 2 can provide a stable air extraction pressure, ensuring a constant airflow through the laser detection chamber 3.

[0033] like Figure 2 and Figure 3 As shown, to clearly illustrate the airflow path, the related components through which the gas passes in this operating mode are highlighted in green. The gas path module 4 also includes an exhaust channel 46. One end of the exhaust channel 46 is connected to both the delivery pipe 41 and the exhaust pipe 42 via a tee 45. The other end of the exhaust channel 46 is fitted with a sealable material. Please refer to... Figure 3 and Figure 5 The delivery pipe 41 is L-shaped and located inside the air circuit module 4. The air inlet of the delivery pipe 41 is connected to the normally open exhaust port 62 of the solenoid valve 6. The airflow entering the solenoid valve is connected to the exhaust channel 46 through the delivery pipe 41 to discharge the air output by the air pump 2. The normal measurement process is as follows: Please refer to Figure 3 , Figure 3 The red lines indicate the airflow path. When in use, the air pump 2 is started, and the air pump 2 generates negative pressure through the air extraction port 21. The air to be tested enters from the air inlet 11 of the air intake module 1 and is transported to the air intake end of the laser detection chamber 3 through the air intake pipe 12. The air to be tested flows through the laser detection area in the laser detection chamber 3. The dust particles are irradiated by the laser and generate scattered light. The scattered light is focused by the light focusing component and received by the light signal conversion component and converted into an electrical signal. The electrical signal is transmitted to the processing module to calculate the dust concentration. The tested air flows out from the air outlet 31 of the laser detection chamber 3 and enters the dust collection component 5. The dust in the air is captured by the filter membrane in the filter membrane box. The air after removing the dust continues to flow to the air extraction port 21 of the air pump 2. After being pressurized by the air pump 2, it is discharged from the exhaust port 22. After passing through the return pipe 44, it enters the solenoid valve and flows to the delivery pipe 41. Finally, it is discharged outside the instrument through the exhaust channel 46.

[0034] Example 2 Based on Example 1, this example adds a backflush filter module 7 and a backflush air path 8 to achieve self-cleaning inside the instrument.

[0035] like Figure 4 As shown, the delivery pipe 41 is connected to the exhaust pipe 42 and the return air passage 8 via a tee 45. The exhaust pipe 42 is fixed to the outer wall of the housing of the air passage module 4.

[0036] Solenoid valve 6 has a normally open air inlet 61, which is connected to the exhaust port 22 of air pump 2 via return pipe 44. Inside the air circuit module 4, solenoid valve 6 also has a normally open exhaust port 62 that can connect to the normally open air inlet 61, and the normally open exhaust port 62 is connected to the delivery pipe 41. When the instrument is in normal measurement operation and self-cleaning mode, solenoid valve 6 controls the normally open air inlet 61 to connect to the normally open exhaust port 62, thus connecting the exhaust port 22 of air pump 2 to the delivery pipe 41. When the instrument is in self-cleaning mode, the airflow in the delivery pipe 41 flows towards the return air circuit 8.

[0037] The backflush filter module 7 is installed at the bottom of the air path module 4 and is located on the backflush air path 8. It is detachably connected to the backflush air path 8, including but not limited to threaded connections, to facilitate periodic disassembly, maintenance or replacement of internal filter media, such as but not limited to HEPA filter media. The backflush filter module 7 is used to filter dust in the air discharged by the air pump 2 to ensure that the airflow entering the backflush air path 8 is clean airflow.

[0038] One end of the return air path 8 is connected to the delivery pipe 41 through the exhaust pipe 42, and the other end is connected to the laser detection chamber 3 through the branch air passage 81. The return air path 8 includes multiple branch air passages 81. The air outlet of each branch air passage 81 is set in the area inside the laser detection chamber 3 where dust is easy to accumulate, such as around the laser emitting component and the surface of the optical signal conversion component, to ensure that the clean return airflow can accurately blow away the areas where dust is easy to accumulate.

[0039] The sealing plug 43 is a removable sealing plug that is adapted to the outlet end of the exhaust passage 46. In the self-cleaning state, the sealing plug is installed at the outlet end of the exhaust passage 46 to seal the exhaust passage 46.

[0040] It should be noted that the connection between the delivery pipe 41 and the return air path 8 will not affect the normal measurement operation of this measuring instrument. This is because during normal measurement operation, the outlet end of the exhaust channel 46 is connected to the external atmosphere, and there is a pressure difference between the return air path 8 and the external atmosphere, which causes the airflow to preferentially pass through the exhaust channel 46 and be quickly discharged.

[0041] The self-cleaning process is as follows: Please refer to Figure 4 To clearly show the airflow path, the related components that the gas passes through in this operating mode are highlighted in green. Figure 4The red lines in the diagram indicate the airflow path. When using the device, first seal the outlet end of the exhaust passage 46 with the sealing plug, then cover the intake module 1 with the cap to seal the intake port 11. Start air pump 2 and switch solenoid valve 6 so that the air discharged from exhaust port 22 of air pump 2 enters the return pipe 44, the normally open air inlet 61 of solenoid valve, the normally open exhaust port 62, and the delivery pipe 41 in sequence, and flows to exhaust pipe 42 and return air path 8. The air first flows through the return filter module 7 and becomes clean airflow after filtration. The clean airflow is delivered to the dusty areas inside the laser detection chamber 3 through several branch air passages 81 of the return air path 8, and blows away the dust on the surface of the laser emitting component, the optical signal conversion component and the inner wall of the air path. The dusty airflow after blowing out flows out from the air outlet 31 of the laser detection chamber 3 and enters the dust collection component 5. The dust is captured by the filter membrane, and the airflow continues to enter air pump 2 through the air intake port 21 of air pump 2 to form a self-cleaning cycle. After repeating the cycle multiple times, remove the sealing plug, switch solenoid valve 6 to the normal exhaust state, and discharge the residual dusty airflow to complete the self-cleaning.

[0042] Example 3 Based on Example 1 or Example 2, this example adds a zero-point calibration filter module 9 and a calibration circulation gas path to achieve instrument zero-point calibration. The zero-point calibration filter module 9 is installed at the bottom of the air circuit module 4 and is located on the calibration circulation air circuit. It is detachably connected to the calibration circulation air circuit, such as including but not limited to threaded connection, snap-fit ​​connection, interference fit, etc., which facilitates maintenance and replacement. The zero-point calibration filter module 9 has high filtration accuracy, ensuring that it can filter out dust particles in the air and output dust-free clean air. Figure 5 The diagram illustrates the rear structure inside the laser measuring instrument. The zero-point calibration filter module 9 is connected to the air intake pipe 12 inside the air intake module 1 via the ventilation pipe 10, thus achieving communication with the air intake end of the laser detection chamber 3. The main body of the ventilation pipe 10 can be installed on the outer wall of the air circuit module 4, making the pipe installation and overall structural layout and disassembly more flexible.

[0043] The solenoid valve 6, located inside the air circuit module 4, also includes a calibration exhaust port 63. The solenoid valve 6 controls the connection / disconnection between the calibration exhaust port 63 and the normally open air inlet 61. When the normally open air inlet 61 is connected to the calibration exhaust port 63, the normally open air inlet 61 is disconnected from the normally open exhaust port 62. The calibration exhaust port 63 is connected to the air inlet of the zero-point calibration filter module 9. Therefore, one end of the zero-point calibration filter module 9 is connected to the exhaust port 22 of the air pump 2 via the solenoid valve 6, and the other end is connected to the air inlet pipe 12 via the air passage pipe 10. The solenoid valve 6 controls the connection / disconnection of the calibration circulation air circuit, ensuring that airflow only occurs within the calibration circulation air circuit during calibration.

[0044] The sealing plug 43 is the same as the sealing plug in Example 2, and is used to seal the exhaust passage 46 in the zero-point calibration state.

[0045] The zero-point calibration process is as follows: Seal the outlet end of the exhaust channel with a sealable material 43 (e.g., a sealing plug), and cover the intake module 1 with the cap to seal the intake port 11. Start the air pump 2 and switch the solenoid valve 6 so that the air discharged from the exhaust port 22 of the air pump 2 enters the calibration circulation air path; the air first flows through the zero-point calibration filter module 9, and becomes dust-free clean air after filtration; the clean air enters the intake pipe 12 through the ventilation pipe 10, and is then delivered to the intake end of the laser detection chamber 3; when the clean air flows through the laser detection chamber 3, no dust particles generate scattered light, and the optical signal conversion component outputs a reference electrical signal, i.e., the zero-point signal. The processing module records the reference signal to complete the zero-point calibration; after calibration, remove the sealing plug, switch the solenoid valve 6 to the normal exhaust state, and restore the normal measurement function.

[0046] The gas path structure of the dust concentration laser measuring instrument of this invention overcomes the defects of the prior art through the following structural design: This application solves the problem of unstable air intake and improves measurement accuracy. By replacing the existing external fan with an air pump, a stable suction power is provided, ensuring a constant airflow through the laser detection chamber and avoiding particle counting deviations caused by airflow fluctuations, thus significantly improving the accuracy of dust concentration measurement.

[0047] This application solves the problem of internal dust accumulation and extends the instrument's lifespan. It incorporates a back-blowing filter module and a back-blowing air path, controlled by a solenoid valve to create a self-cleaning cycle. The clean airflow precisely cleans the laser detection chamber and areas prone to dust accumulation within the air path, reducing wear and tear on components and signal interference caused by dust buildup, thus extending the instrument's lifespan.

[0048] This application also solves the problem of poor portability and expands the scope of application. By integrating the air pump, laser detection chamber, solenoid valve, and filter module into one unit, and with all components connected through an integrated air circuit, there is no need for external fans and separate modules, which significantly reduces the size of the instrument, improves portability, and makes it suitable for on-site mobile detection scenarios.

[0049] This application integrates dust collection and zero-point calibration, resulting in more comprehensive functionality. The dust collection component can simultaneously collect dust samples for subsequent analysis; the zero-point calibration filter module and calibration circulation gas path enable periodic calibration of the measurement benchmark, further ensuring measurement accuracy.

[0050] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A gas path structure for a dust concentration laser measuring instrument, characterized in that, include: An air intake module, wherein the air intake module is provided with an air intake port for introducing the air to be detected; An air pump having an air intake port and an air exhaust port; A laser detection chamber, the laser detection chamber having an air inlet and an air outlet, the air inlet being connected to the air inlet module, and the air outlet being connected to the air pump's suction port; A dust collection assembly is provided in the air path between the air outlet of the laser detection chamber and the air intake of the air pump, and a filter membrane box is provided inside the dust collection assembly. An exhaust passage is provided, which is connected to the exhaust port of the air pump and is used to discharge the air output by the air pump.

2. The gas path structure of the dust concentration laser measuring instrument according to claim 1, characterized in that, It also includes solenoid valves, backflush filter modules, and backflush air paths; The solenoid valve has a normally open air inlet and a normally open air outlet. The normally open air inlet is connected to the air outlet of the air pump, and the normally open air outlet is connected to the delivery pipeline. The other end of the delivery pipeline is connected to the exhaust channel and the return air path. The back-blowing filter module is disposed on the back-blowing air path; the end of the back-blowing air path away from the solenoid valve is connected to the laser detection chamber. The exhaust channel is equipped with a sealable material at its end. When the sealable material blocks the exhaust channel, a backflow airflow channel is formed from the exhaust port of the air pump through the solenoid valve, the delivery pipe, the backflow filter module, and the laser detection chamber.

3. The gas path structure of the dust concentration laser measuring instrument according to claim 2, characterized in that, The back-blowing air path includes at least two branch air channels, and the outlet of each branch air channel is respectively set in the area inside the laser detection chamber where dust is easy to accumulate.

4. The gas path structure of the dust concentration laser measuring instrument according to claim 1 or 2, characterized in that, This also includes calibrating the recirculation gas path; One end of the calibration circulation gas path is connected to a solenoid valve, and the other end is connected to the air inlet of the laser detection chamber; a zero-point calibration filter module is installed on the calibration circulation gas path; The exhaust channel is equipped with a sealable material at its end. When the sealable material blocks the exhaust channel, a calibration circulation air path is formed from the air pump exhaust port through the solenoid valve, the zero-point calibration filter module, the laser detection chamber, the dust collection component, and the air pump intake port.

5. The gas path structure of the dust concentration laser measuring instrument according to claim 4, characterized in that: The sealable material is a removable sealing plug, which is adapted to the outlet end of the exhaust channel.

6. The gas path structure of the dust concentration laser measuring instrument according to claim 2, characterized in that: The end of the delivery pipeline is connected to the exhaust channel and the return air path via a tee. The solenoid valve controls the flow of air in the delivery pipeline by controlling the normally open exhaust port to connect to the normally open air inlet.

7. The gas path structure of the dust concentration laser measuring instrument according to claim 4, characterized in that: The solenoid valve is also provided with a calibration exhaust port. The exhaust port of the air pump is connected to the calibration circulation air circuit through the calibration exhaust port. The solenoid valve controls the conduction of the calibration circulation air circuit by controlling the calibration exhaust port to connect to the normally open air inlet.

8. The gas path structure of the dust concentration laser measuring instrument according to claim 4, characterized in that: An air intake pipe is provided between the air intake end of the laser detection chamber and the air intake port of the air intake module. The air intake pipe is used to connect the air intake port and the laser detection chamber. The zero-point calibration filter module is connected to the air intake pipe through a ventilation pipe.

9. The gas path structure of the dust concentration laser measuring instrument according to claim 4, characterized in that: The zero-point calibration filter module is detachably connected to the calibration circulation gas path.

10. The gas path structure of the dust concentration laser measuring instrument according to claim 2, characterized in that: The backflush filter module and the backflush air path are detachably connected.

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