Particulate matter concentration detection device

Abstract

The utility model relates to the technical field of detection devices, and discloses a particulate matter concentration detection device, which comprises a shell, an air inlet, an air outlet, an air inlet, an air outlet and an air outlet, the inner cavity is divided into a first area and a second area which are opposite to each other, and the second area is provided with a flow channel isolated from the first area; the flow channel communicates with the air inlet and the air outlet; the detection element is arranged in the second area and is used for detecting the concentration of particulate matters in the flow channel; the fan is arranged in the flow channel and is used for driving the oil smoke airflow in the flow channel to flow; and the circuit board is arranged in the first area and is electrically connected with the detection element and / or the fan. According to the particulate matter concentration detection device, the flow channel is designed to be the independent part isolated from the first area, so that oil fume airflow is prevented from being in direct contact with electronic elements such as a circuit board, the risk of short circuit of the electronic elements caused by oil fume or water vapor deposition is reduced, and the safety and stability of the device are improved.

Description

Technical Field

[0001] This utility model relates to the field of detection device technology, and in particular to a particulate matter concentration detection device. Background Technology

[0002] With the rapid development of modern technology, smart homes have become an important part of people's daily lives, greatly improving convenience and comfort. In the kitchen, the heart of family life, the intelligent upgrading of home appliances is particularly crucial. As a core appliance in the kitchen, the improvement of the range hood's intelligence level is of great significance for improving the kitchen environment and protecting user health.

[0003] Traditional range hoods mostly rely on manual adjustment or preset programs to control the smoke extraction mode, making it difficult to dynamically adjust according to the actual air quality in the kitchen. This can not only lead to poor smoke extraction but also waste energy. Therefore, developing intelligent range hoods that can automatically adjust the smoke extraction mode based on kitchen air quality is particularly important.

[0004] To achieve this goal, existing technologies have attempted to identify kitchen air quality by detecting the concentration of inhalable particulate matter and automatically adjust the smoking mode accordingly. This method utilizes a particulate matter concentration detection device to monitor the concentration of particulate matter in the kitchen air in real time, thereby achieving precise control over the smoking effect.

[0005] However, existing technologies still have many shortcomings in particulate matter detection. Specifically, when particulate matter such as cooking fumes and water vapor passes through a particulate matter concentration detection device, it often comes into direct contact with the device's internal electronic components. Due to the special characteristics of substances such as cooking fumes and water vapor in the kitchen environment, prolonged direct contact with electronic components can lead to problems such as short circuits and damage. This not only affects the normal operation of the range hood but may also pose safety hazards and reduce the product's reliability and lifespan. Utility Model Content

[0006] Addressing the technical problem in existing technologies where direct contact between oil fume flow and internal electronic components leads to short circuits and damage, this invention provides a particulate matter concentration detection device. By setting the flow channel as an independent section isolated from the installation area, direct contact between oil fume flow and circuit boards and other electronic components is avoided, reducing the risk of short circuits caused by oil fume or water vapor deposition, thereby improving the safety and stability of the device.

[0007] This utility model provides a particulate matter concentration detection device, comprising:

[0008] The housing has an internal cavity, and an air inlet and an air outlet are provided on the housing; the internal cavity is divided into a first region and a second region, and the second region is provided with a flow channel isolated from the first region; the flow channel connects the air inlet and the air outlet and is used to guide the flow of oily fumes through it;

[0009] A detection element is disposed in the second region and configured to detect the concentration of particulate matter within the flow channel;

[0010] A fan, located within the flow channel, is used to drive the flow of oil fume within the flow channel;

[0011] A circuit board is disposed in the first area and electrically connected to the detection element and / or the fan.

[0012] In some embodiments, the flow channel comprises, in sequence:

[0013] An air intake section, which is connected to the air inlet;

[0014] The detection section has a detection cavity, through which the detection element detects the concentration of particulate matter;

[0015] The air outlet section is connected to the air outlet.

[0016] In some embodiments, the air inlet section is divided into a front air inlet section connected to the air inlet and a rear air inlet section connected to the detection section. The front air inlet section and the rear air inlet section are arranged perpendicularly, and an arc-shaped air guide surface is provided at the connection between the two.

[0017] In some embodiments, the air inlet and air outlet are located on the same side of the housing.

[0018] In some embodiments, the flow channel is formed by bending at least along the two side walls of the housing; the detection chamber is located near the air inlet.

[0019] In some embodiments, the flow channel is formed by bending at least along the two side walls of the housing; the detection chamber is located near the air outlet.

[0020] In some embodiments, the detection element includes a light emitter and a light receiver; the light emitter is disposed on the inner ring side of the flow channel away from the housing sidewall.

[0021] In some embodiments, the fan is positioned close to the air outlet.

[0022] In some embodiments, the housing includes a front shell, a middle shell, and a rear shell that interlock with each other. A partition portion is provided inside the middle shell. A first region is defined between the front shell and one side of the partition portion. A second region is defined between the rear shell and the other side of the partition portion.

[0023] In some embodiments, the side of the partition portion is provided with a surrounding wall portion that forms a flow channel sidewall, and the surrounding wall portion defines the flow channel between the flow channel and the rear shell.

[0024] Compared with the prior art, the advantages and positive effects of this utility model are:

[0025] The aforementioned particulate matter concentration detection device, by designing the flow channel as an independent part isolated from the first area, avoids direct contact between the oil fume flow and electronic components such as circuit boards, reducing the risk of short circuits caused by oil fume or water vapor deposition on electronic components, thereby improving the safety and stability of the device. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a perspective view of the particulate matter concentration detection device of this utility model;

[0028] Figure 2 This is an exploded view of the housing of the particulate matter concentration detection device of this utility model;

[0029] Figure 3 This is a schematic diagram of the internal first region of the particulate matter concentration detection device of this utility model. The front shell and the rear shell are not shown in the figure.

[0030] Figure 4 for Figure 3 The front view;

[0031] Figure 5 This is a schematic diagram of the internal second region of the particulate matter concentration detection device of this utility model. The front shell and the rear shell are not shown in the figure.

[0032] Figure 6 for Figure 5 The front view;

[0033] Figure 7 This is a schematic diagram of the structure of the inner shell of the particulate matter concentration detection device of this utility model, and the figure shows a view of one side of the first region;

[0034] Figure 8 This is a schematic diagram of the structure of the middle shell of the particulate matter concentration detection device of this utility model, and the figure shows a view of one side of the second region;

[0035] Figure 9 This is a schematic diagram of the flow of oil fume gas in the particulate matter concentration detection device of this utility model;

[0036] Figure 10 This is a cross-sectional view of the particulate matter concentration detection device of this utility model;

[0037] Figure 11 This is a schematic diagram of the flow of oil fume airflow in some other embodiments of the present invention, where the airflow blocking structure is an open baffle.

[0038] Figure 12 This is a schematic diagram of the structure of the perforated baffle.

[0039] Figure 13 This is a schematic diagram of the flow of oil fume airflow in some other embodiments of the present invention, where the airflow blocking structure is a staggered baffle.

[0040] Explanation of reference numerals in the attached figures:

[0041] 100 - Housing; 110 - Front housing; 111 - Air inlet; 112 - Air outlet; 120 - Middle housing; 121 - Partition section; 122 - Enclosure section; 1221 - Through hole; 133 - Oil baffle; 1331 - Small hole; 134 - First oil drip port; 135 - Second oil drip port; 130 - Rear housing;

[0042] 200 - Circuit board;

[0043] 300 - Detection element; 310 - Light emitter; 320 - Light receiver;

[0044] 400-fan;

[0045] 500 - Airflow blocking structure; 510 - Columnar structure; 520 - Perforated baffle; 530 - Staggered baffle;

[0046] Area A, Part 1;

[0047] Second area B;

[0048] Flow channel F; Inlet section f1; Front inlet section f1-1; Rear inlet section f1-2; Arc-shaped air guide surface a; Detection section f2; Outlet section f3; Detection chamber C;

[0049] Detection element mounting cavity D. Detailed Implementation

[0050] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0051] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, 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.

[0052] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0053] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0054] Reference Figures 1-13 These are some embodiments of the particulate matter concentration detection device of this utility model.

[0055] The particulate matter concentration detection device includes a housing 100, a circuit board 200, a detection element 300, and a fan 400.

[0056] The housing 100 has an internal cavity, and the housing 100 is provided with an air inlet 111 and an air outlet 112. The air inlet 111 and the air outlet 112 are used to guide the oil fume airflow through the internal cavity.

[0057] The internal cavity is divided into two opposing regions, namely region A and region B, as shown in the figure. Figure 3 and Figure 4Area A is the mounting area, used to fix circuit board 200; see [link / reference] Figure 5 and Figure 6 The second area B is the detection area, used to fix the detection element 300.

[0058] The circuit board 200 is used to control the operating status of the detection element 300 and the fan 400.

[0059] The detection element 300 is used to detect the concentration of particulate matter in the airflow entering the device.

[0060] like Figure 5 and Figure 6 As shown, a flow channel F, isolated from the first area A, is provided in the second area B. The flow channel F connects the air inlet 111 and the air outlet 112, guiding the airflow to enter from the air inlet 111, and after being detected by the detection element 300, to be discharged through the air outlet 112 (e.g., ...). Figure 9 (The arrow indicates the direction of the oil fume airflow). This flow channel F is isolated from the first area A, which can prevent the airflow from entering the first area A and avoid the oil fume airflow from directly contacting electronic components such as the circuit board 200.

[0061] Fan 400 is installed inside flow channel F to drive airflow within flow channel F.

[0062] The aforementioned particulate matter concentration detection device, by designing the flow channel F as an independent part isolated from the installation area, avoids direct contact between the oil fume flow and electronic components such as the circuit board 200, reducing the risk of short circuits caused by oil fume or water vapor deposition on electronic components, thereby improving the safety and stability of the device.

[0063] In this embodiment, see Figure 9 The flow channel F includes an air inlet section f1, a detection section f2, and an air outlet section f3. The air inlet section f1 is connected to the air inlet 111, the detection section f2 has a detection cavity C, and the detection element 300 detects the particulate matter concentration in the oil fume airflow through the detection cavity C. The air outlet section f3 is connected to the air outlet 112 and is used to discharge the detected airflow.

[0064] Furthermore, such as Figure 7 As shown, the air inlet section f1 is divided into a front air inlet section f1-1 connected to the air inlet 111 and a rear air inlet section f1-2 connected to the detection section f2. The front air inlet section f1-1 and the rear air inlet section f1-2 are arranged perpendicularly, and an arc-shaped air guide surface a is provided at the connection between the two. When the airflow enters the rear air inlet section f1-2 from the front air inlet section f1-1, the airflow direction changes through the arc-shaped air guide surface a. The design of the arc-shaped air guide surface a effectively guides the external airflow smoothly into the detection section f2, reduces airflow turbulence, and improves the stability of the airflow through the flow channel F, thereby improving the accuracy of the detection.

[0065] In this embodiment, the flow channel F is arranged along at least two side walls of the housing 100, forming a bent airflow channel. For example, when the flow channel F is arranged along two side walls of the housing 100, it forms an L-shaped flow channel; when it is arranged along three side walls of the housing 100, it forms an inverted U-shaped flow channel.

[0066] The detection chamber C is positioned close to the air inlet 111. Since the detection element 300 is located where the airflow just enters the flow channel F, oil fume particles can quickly enter the detection chamber C, and the detection element 300 can immediately sense the concentration of particles in the airflow, achieving a rapid response.

[0067] In another embodiment, the detection chamber C can be arranged close to the air outlet 112 (not shown), which helps to extend the path of the oil fume airflow in the flow channel F, and the airflow tends to be stable near the air outlet 112. The detection element 300 can then operate in a stable airflow environment, thereby improving the reliability of the detection results and reducing measurement errors caused by airflow fluctuations.

[0068] In this embodiment, the fan 400 is located inside the air outlet 112. Through the action of the fan 400, the oil fume airflow can form a continuous flow within the flow channel F. The fan 400 is not only responsible for guiding the oil fume airflow into the flow channel F, but also for optimizing the flow state of oil fume particles by adjusting the airflow speed, ensuring that the particles are accurately detected when passing through the detection section f2.

[0069] In this embodiment, as Figure 1 As shown, the air inlet 111 and the air outlet 112 are located on the same side of the housing 100. When the particulate matter concentration detection device is installed on the equipment, it can ensure that the exhaust oil fume airflow can be discharged into the external environment. At the same time, the fact that both the air inlet and outlet are arranged from the same side of the housing 100 simplifies the installation layout of the detection device and other equipment components, making it easier to integrate the particulate matter concentration detection device into a compact space.

[0070] See Figure 9 The detection element 300 is an optical sensor, including a light emitter 310 and a light receiver 320.

[0071] Optical sensors measure the concentration of particulate matter in the air based on the principle of light scattering. When light passes through air containing particulate matter, the particulate matter scatters the light, and the optical sensor calculates the concentration of particulate matter by detecting the intensity of the scattered light.

[0072] Specifically, the light emitter 310 emits light to illuminate particulate matter in the air. The light emitter 310 can be an infrared light-emitting diode (IR LED) or a laser diode. A laser light source is preferred because it has higher accuracy and stability, meeting the requirements of high-precision measurement.

[0073] The light emitted by the light emitter 310 enters the detection cavity C through the through hole opened on the flow channel F.

[0074] The light receiver 320 is located inside the detection cavity C and is used to receive light scattered by particulate matter. The light receiver 320 is typically a photoelectric conversion device such as a photodiode or phototransistor, which can convert the received light signal into an electrical signal, and then process it through circuitry to obtain the concentration information of the particulate matter.

[0075] In this embodiment, the light emitter 310 is disposed on the inner ring side of the flow channel F away from the side wall of the housing 100, approximately in the middle of the housing 100, which optimizes the utilization of the internal space and makes the overall structure of the device more compact.

[0076] In this embodiment, as Figure 2 As shown, the housing 100 includes a front housing 110, a middle housing 120, and a rear housing 130 that interlock with each other. An air inlet 111 and an air outlet 112 are provided on the front housing 110. Figure 7 As shown, a partition 121 is provided inside the middle shell 120. A first region A is defined between the front shell 110 and one side of the partition 121; a second region B is defined between the rear shell 130 and the other side of the partition 121. The circuit board 200 is fixed to the partition 121. The front shell 110 and the rear shell 130 enclose the middle shell 120, and a snap fastener is provided on the middle shell 120, which is fixedly connected to the front shell 110 and the rear shell 130 through the snap fastener structure.

[0077] like Figure 8 As shown, the side of the partition portion 121 is provided with a wall portion 122 that forms the side wall of the flow channel F, and the flow channel F is defined between the wall portion 122, the partition portion 121 and the rear shell 130.

[0078] See Figure 5 , 6 and Figure 9 The air inlet section f1 of the flow channel F is also equipped with an airflow blocking structure 500, which is located upstream of the detection chamber C. The airflow blocking structure 500 enables the oil fume airflow in the flow channel F to collide multiple times. Through these collisions, larger particles in the oil fume airflow can be broken down into smaller particles before entering the detection chamber C.

[0079] This particulate matter concentration detection device, through the collision and decomposition effect of the airflow obstruction structure 500, can prevent large particles from settling and accumulating oil in the detection chamber C, thus avoiding contamination of the detection element 300 and affecting its detection accuracy. Simultaneously, after large particles pass through the airflow obstruction structure 500, they break into smaller particles of similar diameter, resulting in a more uniform distribution as they pass through the detection element 300, thereby improving detection accuracy and efficiency.

[0080] In this embodiment, the airflow obstruction structure 500 includes multiple cylindrical structures 510, which are arranged in an alternating manner within the flow channel F. The cross-section of the cylindrical structures 510 is not specifically limited and can be circular, elliptical, rhomboid, etc. The staggered arrangement of the cylindrical structures 510 within the flow channel F allows particulate matter in the oil fume airflow to undergo multiple impacts and separation processes as it passes through, thereby effectively improving the decomposition efficiency of large particles.

[0081] In other embodiments, such as Figure 11 and Figure 12 As shown, the airflow blocking structure 500 can employ perforated baffles 520 with multiple openings, which are sequentially arranged within the flow channel F along the airflow direction. The multiple perforated baffles 520 are staggered, with the openings on adjacent baffles not completely overlapping. This allows particulate matter in the oil fume airflow to collide and separate multiple times as it passes through the perforated baffles 520, further enhancing the decomposition effect of large particles. The perforated baffles 520 can be tilted relative to the airflow direction to allow oil droplets accumulated on the baffles to drip smoothly.

[0082] In other embodiments, such as Figure 13 As shown, the airflow obstruction structure 500 adopts a staggered baffle 530 design. Multiple staggered baffles 530 form an S-shaped meandering flow channel within the flow channel F. Through this structure, the oil fume airflow undergoes multiple turns within the flow channel F, causing particles to continuously collide and separate, reducing the presence of large particles. The staggered baffles 530 can be tilted relative to the airflow direction to allow oil droplets accumulated on the baffles to drip smoothly.

[0083] In some other embodiments, the airflow obstruction structure 500 may be a labyrinth channel structure (not shown). The labyrinth channel has multiple tortuous paths. As the oil fume airflow passes through the labyrinth channel, the airflow direction continuously changes, causing particles to collide in different directions, thereby breaking them down into smaller particles and reducing particle deposition. Simultaneously, the tortuous paths in the labyrinth structure effectively reduce airflow turbulence and ensure uniform distribution of particles within the channel F, ultimately ensuring efficient and accurate detection when the particles enter the detection chamber C.

[0084] In this embodiment, both the airflow obstruction structure 500 and the detection chamber C are arranged close to the air inlet 111. For ease of manufacturing or installation, the airflow obstruction structure 500 is located in the rear section f1-2 of the air inlet. By arranging the airflow obstruction structure 500 close to the air inlet 111, particulate matter can be decomposed and processed in the early stages of the oil fume airflow entering the flow channel F, reducing the interference of large particles on subsequent detection processes. With the detection chamber C positioned close to the airflow obstruction structure 500, the detection element 300 can immediately sense the concentration of particulate matter in the airflow, achieving a rapid response.

[0085] In other embodiments, the airflow blocking structure 500 is arranged near the air inlet 111, and the detection chamber C is arranged near the air outlet 112, so as to extend the path of the oil fume airflow in the flow channel F and improve the reliability of the detection results.

[0086] The airflow obstruction structure 500 is either an integral part of the flow channel F or a detachable installation structure. An integrally molded structure improves the overall stability of the device and reduces assembly steps; while a detachable structure facilitates maintenance and cleaning. Users can disassemble and replace the airflow obstruction structure 500 according to actual usage, ensuring the device is always in optimal working condition.

[0087] Because the light-emitting window of the light emitter 310 is quite sensitive, direct contact with oil fumes, water vapor, or particulate matter can easily cause deviations in the intensity and angle of light emission, thus affecting the accuracy of the detection results. To prevent oil fumes, water vapor, etc., from affecting the light emitter 310 and its detection accuracy, in this embodiment, such as... Figure 9 and Figure 10 As shown, a detection element mounting cavity D is provided on one side of the detection cavity C. The light emitter 310 is disposed in the detection element mounting cavity D. A through hole 1221 is provided on the side wall of the flow channel F. The light emitted by the light emitter 310 enters the detection cavity C through the through hole. At least one oil baffle 133 is provided between the light emitter 310 and the detection cavity C. The oil baffle 133 has a small hole 1331 for light to pass through.

[0088] This particulate matter concentration detection device isolates the light emitter 310 from the oil fume flow by setting a detection element mounting cavity D on one side of the detection cavity C, thus preventing the light emitter 310 from being directly exposed to the oil fume flow. At the same time, by setting at least one layer of oil baffle 133, the small holes on the oil baffle 133 allow light to pass through smoothly while effectively blocking the intrusion of most oil fume particles, further preventing the oil fume flow from entering the detection element mounting cavity D and directly contacting the light emitter 310. This greatly improves the device's anti-pollution capability, enabling the light emitter 310 to maintain normal operation for a long time in a relatively harsh oil fume environment, ensuring the accuracy and reliability of the detection.

[0089] To effectively drain the oil accumulated in the flow channel F, this device provides a first oil drip port 134 at the bottom of the flow channel F near the air outlet 112, and a second oil drip port 135 at the bottom of the flow channel F below the airflow obstruction structure 500 (e.g., Figure 9 (The hollow arrow indicates the direction of oil droplet flow). The two oil drip outlets can smoothly discharge oil, keep the flow channel F clean, prevent oil accumulation from obstructing the normal flow of air in the flow channel F, and ensure the long-term stable operation of the device.

[0090] In this embodiment, both the air inlet 111 and the air outlet 112 are located near the bottom of the housing 100. The flow channel F is roughly U-shaped inside the housing 100. To facilitate the complete discharge of oil stains from the flow channel F, the top portion of the flow channel F is slightly inclined downwards, allowing oil droplets to flow downwards under gravity and exit from the first oil droplet outlet 134. It is understood that in another embodiment, when the detection chamber C is located near the air outlet 112, the top portion of the flow channel is inclined towards the air inlet 111, so that oil droplets are discharged from the second oil droplet outlet 135 below the air inlet 111, preventing them from flowing into the detection chamber C and affecting detection accuracy.

[0091] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this 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. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by this utility model.

Claims

1. A particulate matter concentration detection device, characterized in that, include: A housing having an internal cavity, wherein an air inlet and an air outlet are provided on the housing; the internal cavity is divided into a first region and a second region, wherein the second region is provided with a flow channel isolated from the first region; the flow channel connects the air inlet and the air outlet; A detection element is disposed in the second region and configured to detect the concentration of particulate matter within the flow channel; A fan, located within the flow channel, is used to drive the airflow within the flow channel; A circuit board is disposed in the first area and electrically connected to the detection element and / or the fan.

2. The particulate matter concentration detection device according to claim 1, characterized in that, The flow channels sequentially include: An air intake section, which is connected to the air inlet; The detection section has a detection cavity, through which the detection element detects the concentration of particulate matter; The air outlet section is connected to the air outlet.

3. The particulate matter concentration detection device according to claim 2, characterized in that, The air intake section is divided into a front air intake section connected to the air inlet and a rear air intake section connected to the detection section. The front air intake section and the rear air intake section are arranged perpendicularly, and an arc-shaped air guide surface is provided at the connection between the two.

4. The particulate matter concentration detection device according to claim 2, characterized in that, The air inlet and air outlet are located on the same side of the housing.

5. The particulate matter concentration detection device according to claim 2, characterized in that, The flow channel forms a bent flow channel at least along the two side walls of the housing; the detection chamber is located close to the air inlet.

6. The particulate matter concentration detection device according to claim 2, characterized in that, The flow channel forms a bent flow channel at least along the two side walls of the housing; the detection chamber is located near the air outlet.

7. The particulate matter concentration detection device according to claim 5 or 6, characterized in that, The detection element includes a light emitter and a light receiver; the light emitter is located on the inner ring side of the flow channel away from the housing sidewall.

8. The particulate matter concentration detection device according to claim 1, characterized in that, The fan is positioned close to the air outlet.

9. The particulate matter concentration detection device according to claim 1, characterized in that, The housing includes a front shell, a middle shell, and a rear shell that interlock with each other. A partition portion is provided inside the middle shell. A first region is defined between the front shell and one side of the partition portion. A second region is defined between the rear shell and the other side of the partition portion.

10. The particulate matter concentration detection device according to claim 9, characterized in that, The side of the partition is provided with a surrounding wall portion that forms a flow channel sidewall, and the flow channel is defined between the surrounding wall portion and the rear shell.

Images