Extraction type particulate matter measuring instrument

Abstract

The utility model provides a removable particulate matter measuring instrument. The removable particulate matter measuring instrument comprises a measuring cavity, a sampling probe assembly, a detection probe assembly, an air pump assembly, an annular light scattering light path assembly and an annular light scattering adjusting mechanism, the sampling probe assembly, the detection probe assembly and the air pump assembly are detachably mounted at the upper end of the measuring cavity, a measuring chamber is arranged at the lower end of the measuring cavity, and the sampling probe assembly and the air pump assembly are communicated with the measuring chamber; the annular light scattering light path assembly comprises a transmitting unit and a receiving unit, the transmitting unit and the receiving unit are arranged on the two sides of the measuring chamber respectively, and light emitted by the transmitting unit is received by the receiving unit after passing through the measuring chamber. Through multiple technical innovations, the measurement precision, the environmental adaptability, the multi-parameter measurement capability, the installation and maintenance convenience and the cleaning and protection performance of the particulate matter measurement instrument are remarkably improved, and a particulate matter measurement solution which is efficient, reliable and easy to maintain is provided.

Description

TECHNICAL FIELD

[0001] The utility model relates to environmental monitoring equipment technical field, concretely relates to a kind of extracted particulate matter measuring instrument. BACKGROUND

[0002] With the enhancement of environmental protection consciousness, the monitoring of atmospheric pollutants, especially particulate matter, becomes more and more important. Traditional particulate matter measurement methods mainly include gravimetric method, optical method, etc. Among them, optical method is widely used in environmental monitoring field due to its non-contact, fast response, simple operation and other characteristics. However, the existing optical particulate matter measuring instrument still has some problems in practical application, such as low measurement accuracy, easy to be affected by environmental factors, inconvenient maintenance, etc.

[0003] Disadvantages of prior art:

[0004] 1. Insufficient measurement accuracy: traditional particulate matter measuring instrument may cause large background light interference due to unreasonable optical path design, affecting measurement accuracy. In addition, the lack of effective calibration mechanism also leads to deviation of measurement results.

[0005] 2. Poor environmental adaptability: in high temperature, high pressure or corrosive environment, the performance of traditional measuring instrument will decrease significantly, and even cannot work normally. For example, sampling probe is easy to be contaminated, leading to measurement error.

[0006] 3. Limited multi-parameter measurement capability: existing measuring instrument can only measure particulate matter concentration singlely, and is difficult to measure other important parameters such as temperature, pressure and flow of sample gas at the same time.

[0007] 4. Inconvenient installation and maintenance: the installation and maintenance process of traditional instrument is relatively complex, which needs frequent disassembly and calibration, increasing the operation difficulty and cost.

[0008] 5. Weak anti-interference ability: the optical path design and calibration mechanism of traditional instrument are not perfect, which is easy to be disturbed by external environmental factors (such as temperature and humidity change), leading to unstable measurement results.

[0009] 6. Insufficient cleaning and protection measures: sensor window and optical element are easy to be contaminated, and lack effective protection measures, affecting the stability and reliability of long-term use.

[0010] Therefore, the prior art has disadvantages, and needs to be further improved. Utility model content

[0011] In view of the problems existing in the prior art, the utility model provides a kind of extracted particulate matter measuring instrument.

[0012] To achieve the above purpose, the specific scheme of the utility model is as follows:

[0013] The utility model provides a kind of extractable particulate matter measuring instrument, comprising:

[0014] Measuring cavity, sampling probe assembly, detection probe assembly, air pump assembly, annular light scattering optical path assembly, annular light scattering calibration mechanism;

[0015] The sampling probe assembly, detection probe assembly, air pump assembly can be detachably installed at the upper end of the measuring cavity, the lower end of the measuring cavity is provided with a measuring chamber, and the sampling probe assembly and the air pump assembly are communicated with the measuring chamber.

[0016] The annular light scattering optical path assembly includes a transmitting unit and a receiving unit, which are respectively arranged on both sides of the measuring chamber, and the light emitted by the transmitting unit is received by the receiving unit after passing through the measuring chamber.

[0017] The annular light scattering calibration mechanism is arranged between the transmitting unit and the receiving unit during calibration, and is used for calibrating the annular light scattering optical path assembly.

[0018] The sampling probe assembly is used for collecting sample gas and injecting it into the measuring chamber, the detection probe assembly is used for detecting temperature, pressure and flow rate, the air pump assembly is used for providing extraction power for the sampling probe assembly, the annular light scattering optical path assembly is used for detecting the concentration of particulate matter in the measuring chamber, and the annular light scattering calibration mechanism is used for calibrating the annular light scattering optical path assembly.

[0019] Further, the lower end of the measuring chamber is further provided with a cover.

[0020] Further, the detection probe assembly includes a back pressure pipe and a full pressure pipe.

[0021] The opening of the full pressure pipe faces the fluid incoming side, and the opening of the back pressure pipe faces away from the fluid incoming side.

[0022] Further, the sampling probe assembly includes a sample gas extraction pipeline and a first heating pipe.

[0023] The sample gas extraction pipeline is communicated with the measuring chamber, and the front end of the sample gas extraction pipeline is further provided with a bent nozzle, which faces the fluid incoming side.

[0024] The first heating pipe is arranged at the side of the sample gas extraction pipeline, and is used for heating the extracted sample gas.

[0025] Further, the air pump assembly is further provided with a first channel, an air outlet, a negative pressure port and a compressed air inlet.

[0026] The air outlet and the negative pressure port are arranged at the front end and the tail end of the first channel respectively, and the compressed air inlet is arranged on the side wall of the first channel between the air outlet and the negative pressure port;

[0027] The compressed air inlet is connected with an external compressed air source, and compressed gas enters the first channel from the compressed air inlet and is discharged from the air outlet to generate negative pressure at the negative pressure port;

[0028] The negative pressure port is connected with a measuring chamber, and the measuring chamber is connected with a sample gas extraction pipeline of the sampling probe assembly, and under the action of negative pressure, sample gas is extracted into the measuring chamber;

[0029] The measuring cavity is provided with a sample gas discharge channel, and the air outlet is connected with the sample gas discharge channel for discharging sample gas after detection.

[0030] Further, the emitting unit comprises a light source, a collimating lens and a conical lens;

[0031] The receiving unit comprises a receiving lens and a light detector;

[0032] The light source is used for emitting light, and the light passes through the collimating lens and the conical lens in sequence to form an annular measuring area in the measuring chamber;

[0033] The measuring chamber is introduced with sample gas through the sampling probe assembly, and the sample gas contains smoke particles;

[0034] The scattered light generated by the smoke particles in the annular measuring area reaches the light detector through the receiving lens, which is used for evaluating the concentration of particulate matter.

[0035] Further, the annular light scattering calibration mechanism comprises a light adjusting assembly;

[0036] The light adjusting assembly is arranged between the emitting unit and the receiving unit, and is used for adjusting the intensity of light by changing the area of light shielding, so as to realize the purpose of simulating a specific amount of scattered signal, realize the pickup of the range signal and further realize the calibration function.

[0037] Further, the measuring cavity is further provided with an emitting light curtain channel and a receiving light curtain channel;

[0038] The emitting light curtain channel and the receiving light curtain channel are respectively located at the front side of the conical lens and the front side of the receiving lens, and are used for introducing protective gas to form a curtain for isolation and protection at the front side of the conical lens and the receiving lens.

[0039] Further, a second heating pipe is arranged in the measuring cavity for heating the entire heating cavity.

[0040] Further, the detection probe assembly is further provided with a temperature sensor;

[0041] The detection probe assembly and the sampling probe assembly are rotatably installed in the measuring cavity, and the installation angle is adjusted by rotation.

[0042] A fluorine rubber sealing ring is arranged between the detection probe assembly, the sampling probe assembly and the measuring cavity for sealing.

[0043] The technical scheme has the following beneficial effects:

[0044] 1. High measurement accuracy:

[0045] Annular light scattering light path system: through the new annular light path design, the interference of background light is reduced, and the measurement accuracy is improved.

[0046] Annular light scattering calibration mechanism: the light blocking area is changed through the light adjusting assembly to realize the adjustment of light intensity, effectively reduce the original light interference and light path drift, and improve the accuracy and stability of calibration.

[0047] 2. Strong environmental adaptability:

[0048] Vacuum air pump as extraction power: suitable for high temperature, high pressure and corrosive environment, and ensures the simplicity and applicability of operation.

[0049] Heating pipe design: heating pipes are arranged in the sampling probe assembly and the measuring cavity to ensure that the sample gas does not condense under high temperature conditions, and measurement errors are avoided.

[0050] Fluorine rubber sealing ring: fluorine rubber sealing rings are arranged between the detection probe assembly, the sampling probe assembly and the measuring cavity to ensure the sealing property and prevent leakage and pollution.

[0051] 3. Multi-parameter measurement capability:

[0052] Multi-parameter detection probe: the detection probe assembly includes a back pressure pipe, a full pressure pipe and a temperature sensor, which can measure the temperature, pressure and flow rate of the sample gas at the same time, and provides comprehensive measurement data.

[0053] Measuring chamber flow channel system: under the condition that the volume of the measuring chamber is not changed, multi-parameter measurement is realized through optimized structure design, and the comprehensive performance of the instrument is improved.

[0054] 4. Simple installation and maintenance:

[0055] Detachable design: the sampling probe assembly, the detection probe assembly and the air pump assembly can be detachably installed, the installation steps are reduced, and replacement and maintenance are facilitated.

[0056] Rotary adjustment of installation angle: the detection probe assembly and the sampling probe assembly can be rotatably installed, and the installation angle is adjusted by rotation to adapt to different measurement environments and requirements.

[0057] 5. Efficient cleaning protection:

[0058] Air curtain micro-flow control system: By controlling the micro-flow of the air curtain, the sensor window and optical elements are protected from pollution, ensuring long-term stable measurement performance.

[0059] Periodic backflushing function: The sampling probe and detection probe assembly have a periodic backflushing function to ensure the internal measurement chamber is clean and the probe is not clogged.

[0060] 6. Continuity and accuracy:

[0061] Negative pressure extraction and discharge: The air pump assembly extracts sample gas into the measurement chamber through negative pressure, and discharges the sample gas after detection, ensuring the continuity and accuracy of the measurement process.

[0062] Sample gas discharge channel: A sample gas discharge channel is provided on the measurement cavity and connected to the air outlet of the air pump assembly to ensure smooth discharge of the sample gas.

[0063] 7. Compact structure:

[0064] Integrated design: The sampling probe assembly and detection probe assembly are designed in one body and installed directly from the measurement chamber, reducing the overall volume and making the instrument more compact and portable. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 is a perspective view of the present utility model;

[0066] Figure 2 is a sectional view of the present utility model;

[0067] Figure 3 is a sectional view of another position of the present utility model;

[0068] Figure 4 is a sectional view of the third position of the present utility model.

[0069] In the figure:

[0070] 1. Measurement cavity; 2. Air pump assembly; 3. Measurement chamber; 4. Lid; 5. Back pressure pipe; 6. Full pressure pipe; 7. Sample gas extraction pipeline; 8. First heating pipe; 9. Bent nozzle; 10. First channel; 11. Air outlet; 12. Negative pressure port; 13. Compressed air inlet; 14. Sample gas discharge channel; 15. Light source; 16. Collimating lens; 17. Conical lens; 18. Receiving lens; 19. Light detector; 20. Annular measurement area; 21. Smoke dust particles; 22. Light adjustment assembly; 23. Emitted light air curtain channel; 24. Received light air curtain channel; 25. Second heating pipe; 26. First air curtain joint; 27. Second air curtain joint. DETAILED DESCRIPTION

[0071] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0072] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0073] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0074] In the description of this embodiment, the terms "upper," "lower," "front," "rear," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0075] Combination Figures 1-4 As shown, this utility model provides an extractable particulate matter measuring instrument, comprising:

[0076] Measurement cavity 1, sampling probe assembly, detection probe assembly, air pump assembly 2, ring light scattering optical path assembly, ring light scattering calibration mechanism;

[0077] The sampling probe assembly, detection probe assembly, and air pump assembly 2 are detachably mounted on the upper end of the measuring cavity 1. A measuring chamber 3 is provided at the lower end of the measuring cavity 1, and the sampling probe assembly and air pump assembly 2 are connected to the measuring chamber 3.

[0078] The annular light scattering light path assembly comprises a transmitting unit and a receiving unit, which are arranged on two sides of the measuring chamber 3 respectively, and the light emitted by the transmitting unit is received by the receiving unit after passing through the measuring chamber 3;

[0079] The annular light scattering calibration mechanism is arranged between the transmitting unit and the receiving unit during calibration, and is used for calibrating the annular light scattering light path assembly;

[0080] The sampling probe assembly is used for collecting sample gas and injecting it into the measuring chamber 3, the detection probe assembly is used for detecting temperature, pressure and flow rate, the air pump assembly 2 is used for providing suction power for the sampling probe assembly, the annular light scattering light path assembly is used for detecting the concentration of particulate matters in the measuring chamber 3, and the annular light scattering calibration mechanism is used for calibrating the annular light scattering light path assembly.

[0081] The lower end of the measuring chamber 3 is further provided with a cover 4.

[0082] The detection probe assembly comprises a back pressure pipe 5 and a total pressure pipe 6;

[0083] The opening of the total pressure pipe 6 faces the fluid coming side, and the opening of the back pressure pipe 5 faces away from the fluid coming side.

[0084] The sampling probe assembly comprises a sample gas suction pipe 7 and a first heating pipe 8;

[0085] The sample gas suction pipe 7 communicates with the measuring chamber 3, and the front end of the sample gas suction pipe 7 is further provided with a bent nozzle 9 facing the fluid coming side;

[0086] The first heating pipe 8 is arranged on the side of the sample gas suction pipe 7 and is used for heating the suctioned sample gas.

[0087] The air pump assembly 2 is further provided with a first channel 10, an air outlet 11, a negative pressure port 12 and a compressed air inlet 13;

[0088] The air outlet 11 and the negative pressure port 12 are arranged at the front end and the tail end of the first channel 10 respectively, and the compressed air inlet 13 is arranged on the side wall of the first channel 10 between the air outlet 11 and the negative pressure port 12;

[0089] The compressed air inlet 13 is connected with an external compressed air source, and the compressed gas enters the first channel 10 from the compressed air inlet 13 and is discharged from the air outlet 11 to generate negative pressure at the negative pressure port 12;

[0090] The negative pressure port 12 is connected with the measuring chamber 3, and the measuring chamber 3 is connected with the sample gas suction pipe 7 of the sampling probe assembly, so that the sample gas is suctioned into the measuring chamber 3 under the action of negative pressure.

[0091] The measuring cavity 1 is provided with a sample gas discharging channel 14, and the gas outlet 11 is connected with the sample gas discharging channel 14 and used for discharging sample gas after detection.

[0092] The emitting unit comprises a light source 15, a collimating lens 16 and a conical lens 17.

[0093] The receiving unit comprises a receiving lens 18 and a light detector 19.

[0094] The light source 15 is used for emitting light, and the light rays form a ring-shaped measuring area 20 in the measuring chamber 3 after sequentially passing through the collimating lens 16 and the conical lens 17.

[0095] The sample gas containing smoke particles 21 is introduced into the measuring chamber 3 through the sampling probe assembly.

[0096] The scattered light generated by the smoke particles 21 in the ring-shaped measuring area 20 reaches the light detector 19 after passing through the receiving lens 18 and is used for evaluating the concentration of particulate matters.

[0097] The ring-shaped light scattering calibration mechanism comprises a light adjusting assembly 22.

[0098] The light adjusting assembly 22 is arranged between the emitting unit and the receiving unit and is used for adjusting the light intensity by changing the light shielding area, achieving the purpose of simulating a specific amount of scattering signals, picking up the range signals and further achieving the calibration function.

[0099] The measuring cavity 1 is further provided with an emitting light curtain channel 23 and a receiving light curtain channel 24.

[0100] The emitting light curtain channel 23 and the receiving light curtain channel 24 are respectively arranged at the front side of the conical lens 17 and the front side of the receiving lens 18 and are used for introducing protective gas to form a light curtain for isolation and protection at the front side of the conical lens 17 and the receiving lens 18.

[0101] The measuring cavity 1 is provided with a second heating pipe 25 and is used for heating the whole heating cavity.

[0102] The detection probe assembly is further provided with a temperature sensor.

[0103] The detection probe assembly and the sampling probe assembly are rotatably arranged in the measuring cavity 1 and the installation angle is adjusted by rotation.

[0104] The detection probe assembly and the sampling probe assembly are provided with a fluorine rubber sealing ring for sealing between the detection probe assembly and the sampling probe assembly and the measuring cavity 1.

[0105] The principle of the utility model is as follows:

[0106] The utility model provides a kind of extracted particulate measuring instrument, accurate measurement of particulate concentration and other parameters in sample gas is realized by the cooperation of multiple components. The following is the detailed working principle:

[0107] Sampling process:

[0108] Sampling probe assembly: sampling probe assembly includes sample gas extraction pipeline 7 and first heating pipe 8. The front end of sample gas extraction pipeline 7 is provided with a bent mouth 9, and the bent mouth 9 is oriented to one side of fluid flow, so as to more effectively collect sample gas. The first heating pipe 8 is arranged at the side of sample gas extraction pipeline 7, for heating the extracted sample gas, to prevent the sample gas from condensing in the pipeline.

[0109] Air pump assembly 2: air pump assembly 2 includes first channel 10, air outlet 11, negative pressure port 12 and compressed air inlet 13. Compressed air enters first channel 10 from compressed air inlet 13, is discharged from air outlet 11, and at the same time, negative pressure is generated at negative pressure port 12. Negative pressure port 12 is connected with measuring chamber 3, and measuring chamber 3 is connected with sample gas extraction pipeline 7 of sampling probe. Under the action of negative pressure, sample gas is extracted into measuring chamber 3.

[0110] Measurement process:

[0111] Annular light scattering light path assembly: annular light scattering light path assembly includes light source 15, collimating lens 16, cone lens 17, receiving lens 18 and light detector 19. The light emitted by light source 15 passes through collimating lens 16 and cone lens 17 in turn, and forms annular measuring area 20 in measuring chamber 3. Smoke particles 21 in sample gas produce scattered light in annular measuring area 20. The scattered light reaches light detector 19 after passing through receiving lens 18, and light detector 19 converts the scattered light into an electrical signal, which is used to evaluate the concentration of particulate matter.

[0112] Annular light scattering calibration mechanism: annular light scattering calibration mechanism includes a light adjusting assembly 22. The light adjusting assembly 22 adjusts the intensity of light by changing the light blocking area, realizes the purpose of simulating a specific amount of scattered signal, so as to realize the pickup and calibration function of range signal.

[0113] Multi-parameter detection:

[0114] Detection probe assembly: detection probe assembly includes back pressure pipe 5, full pressure pipe 6 and temperature sensor. The opening of full pressure pipe 6 is oriented to one side of fluid flow, for measuring the full pressure of sample gas; the opening of back pressure pipe 5 is oriented to one side of fluid flow, for measuring the back pressure of sample gas. The temperature sensor is used to measure the temperature of sample gas. These parameters are transmitted to the control system through electrical signal, realizing the synchronous measurement of sample gas temperature, pressure and flow rate.

[0115] Cleaning protection:

[0116] Gas curtain micro-flow control system: the measurement cavity 1 is provided with an emitting light gas curtain channel 23 and a receiving light gas curtain channel 24, which are located at the front side of the cone lens 17 and the front side of the receiving lens 18 respectively. By passing protective gas in these channels, a gas curtain is formed to isolate and protect the cone lens 17 and the receiving lens 18, prevent contaminants from adhering, and ensure the cleanliness and long-term stable operation of the optical elements. The outer wall of the measurement cavity 1 is provided with a first gas curtain joint 26 and a second gas curtain joint 27 connected with the receiving light gas curtain channel 24 and the emitting light gas curtain channel 23 respectively.

[0117] Heating and sealing:

[0118] Heating tube: a second heating tube 25 is arranged in the measurement cavity 1 to heat the entire heating cavity, ensure the temperature of the sample gas and the measurement chamber 3 during the measurement process, and avoid condensation and measurement errors.

[0119] Sealing design: a fluorine rubber sealing ring is arranged between the detection probe assembly and the sampling probe assembly and the measurement cavity 1 to ensure the sealing property and prevent leakage and pollution.

[0120] Sample gas discharge:

[0121] Sample gas discharge channel 14: the measurement cavity 1 is provided with a sample gas discharge channel 14 connected with the air outlet 11 of the air pump assembly 2. After the detection is completed, the sample gas is discharged through the sample gas discharge channel 14 to ensure the continuity and accuracy of the measurement process.

[0122] In summary, the utility model realizes the accurate measurement of the particulate matter concentration and other parameters in the sample gas through the cooperative work of multiple links such as sampling, measurement, multi-parameter detection, cleaning protection, heating and sealing. It has the advantages of high precision, strong environmental adaptability, multi-parameter measurement capability and simple installation and maintenance.

[0123] The above only describes the preferred embodiments of the utility model, and does not limit the utility model range, and any equivalent structural transformation or direct / indirect application in other related technical fields under the utility model concept of the utility model is included in the protection range of the utility model.

Claims

1. An extractable particulate matter measuring instrument, characterized in that, include: Measuring cavity, sampling probe assembly, detection probe assembly, air pump assembly, ring light scattering optical path assembly, and ring light scattering calibration mechanism; The sampling probe assembly, detection probe assembly, and air pump assembly are detachably mounted on the upper end of the measuring cavity, and a measuring chamber is provided at the lower end of the measuring cavity. The sampling probe assembly and air pump assembly are connected to the measuring chamber. The ring light scattering optical path assembly includes a transmitting unit and a receiving unit, which are respectively arranged on both sides of the measuring chamber. The light emitted by the transmitting unit is received by the receiving unit after passing through the measuring chamber. The ring light scattering calibration mechanism is set between the transmitting unit and the receiving unit during calibration and is used to calibrate the ring light scattering optical path components. The sampling probe assembly is used to collect sample gas and inject it into the measurement chamber. The detection probe assembly is used to detect temperature, pressure, and flow rate. The air pump assembly is used to provide extraction power for the sampling probe assembly. The annular light scattering optical path assembly is used to detect the concentration of particulate matter in the measurement chamber. The annular light scattering calibration mechanism is used to calibrate the annular light scattering optical path assembly.

2. The extractable particulate matter measuring instrument according to claim 1, characterized in that, The lower end of the measuring chamber is also equipped with a cover.

3. The extractable particulate matter measuring instrument according to claim 1, characterized in that, The detection probe assembly includes a back pressure tube and a full pressure tube; The opening of the full pressure pipe faces the side where the fluid is coming from, and the opening of the back pressure pipe faces away from the side where the fluid is coming from.

4. The extractable particulate matter measuring instrument according to claim 1, characterized in that, The sampling probe assembly includes a sample gas extraction pipe and a first heating tube; The sample gas extraction pipe is connected to the measurement chamber, and the front end of the sample gas extraction pipe is also provided with a bend, which faces the side where the fluid comes from. The first heating tube is located on the side of the sample gas extraction pipeline and is used to heat the extracted sample gas.

5. The extractable particulate matter measuring instrument according to claim 4, characterized in that, The air pump assembly is also provided with a first channel, an air outlet, a negative pressure port, and a compressed air inlet; The air outlet and the negative pressure port are respectively located at the front end and the rear end of the first channel, and the compressed air inlet is located on the side wall of the first channel between the air outlet and the negative pressure port. The compressed air inlet is connected to an external compressed air source. Compressed gas enters the first channel from the compressed air inlet and is discharged from the outlet, generating negative pressure at the negative pressure port. The negative pressure port is connected to the measuring chamber, and the measuring chamber is connected to the sample gas extraction pipe of the sampling probe assembly. The sample gas is extracted into the measuring chamber under the action of negative pressure. The measuring chamber is provided with a sample gas emission channel, and the gas outlet is connected to the sample gas emission channel for discharging the sample gas after testing.

6. The extractable particulate matter measuring instrument according to claim 1, characterized in that, The transmitting unit includes: a light source, a collimating lens, and a conical lens; The receiving unit includes: a receiving lens and a photodetector; The light source is used to emit light, and the light rays pass through a collimating lens and a conical lens in sequence to form a ring-shaped measurement area in the measurement chamber. The sample gas, which contains dust particles, was introduced into the measurement chamber through a sampling probe assembly. The scattered light generated by the dust particles in the annular measurement area passes through the receiving lens and reaches the photodetector, which is used to assess the concentration of particulate matter.

7. The extractable particulate matter measuring instrument according to claim 6, characterized in that, The ring-shaped light scattering calibration mechanism includes a dimming component; The dimming component is located between the transmitting unit and the receiving unit. It is used to adjust the light intensity by changing the area of ​​the light blockage, thereby simulating a specific amount of scattered signal, picking up the range signal, and further realizing the calibration function.

8. The extractable particulate matter measuring instrument according to claim 6, characterized in that, The measuring cavity is also equipped with an emitting light curtain channel and a receiving light curtain channel. The light emission gas curtain channel and the light receiving gas curtain channel are located in front of the conical lens and the receiving lens, respectively, and are used to introduce protective gas into the front of the conical lens and the receiving lens to form a gas curtain for isolation and protection.

9. The extractable particulate matter measuring instrument according to claim 1, characterized in that, The measuring cavity is equipped with a second heating tube for heating the entire heating cavity.

10. The extractable particulate matter measuring instrument according to claim 1, characterized in that, The detection probe assembly is also equipped with a temperature sensor; The detection probe assembly and the sampling probe assembly are rotatably mounted in the measuring cavity, and the mounting angle can be adjusted by rotation; A fluororubber sealing ring is provided between the detection probe assembly and the sampling probe assembly and the measurement cavity for sealing.

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