A particulate matter concentration detection device

Abstract

The utility model discloses a kind of particulate matter concentration detection devices, it is related to environmental protection data analysis technical field, including detector and fixedly installed on the detection component and controller of detector, the upper end of the detector is sealed, lower end is equipped with exhaust pipe, two baffle plates are fixedly sleeved in detector, two baffle plates divide detector into three chambers of upper, middle and lower;The outside of upper chamber is uniformly fixedly installed with multiple air inlet pipes along circumference, one-way exhaust valve I is equipped in air inlet pipe, the other end of air inlet pipe penetrates upper baffle plate and is communicated with middle chamber, piston is slidably sleeved in middle chamber along axial direction.The particulate matter concentration detection device, by the three-chamber division of "upper chamber drive-middle chamber sampling detection-lower chamber exhaust", in combination with linkage of piston and one-way valve, realize "the physical isolation of sampling and detection", avoid cross contamination, solve the low precision problem caused by "sampling-detection integration" of existing device.

Description

Technical Field

[0001] This utility model relates to the field of environmental data analysis technology, specifically a particulate matter concentration detection device. Background Technology

[0002] Existing particulate matter concentration detection devices suffer from uneven airflow during sampling, leading to disordered distribution of particulate matter in the detection area and affecting detection accuracy.

[0003] Therefore, it is necessary to propose a particulate matter concentration detection device to solve the above problems. Utility Model Content

[0004] Technical problem to be solved: The purpose of this utility model is to provide a particulate matter concentration detection device to solve the problem mentioned in the background art that the existing particulate matter concentration detection devices have disordered distribution of particulate matter in the detection area, which affects the detection accuracy.

[0005] Technical Solution: To achieve the above objectives, this utility model provides the following technical solution: A particulate matter concentration detection device includes a detector and a detection assembly and controller fixedly mounted on the detector. The detector is sealed at its upper end and has an exhaust pipe at its lower end. Two partitions are fixedly fitted inside the detector, dividing it into upper, middle, and lower chambers. Multiple air inlet pipes are evenly fixedly installed around the outer circumference of the upper chamber. Each air inlet pipe contains a one-way exhaust valve I. The other end of each air inlet pipe passes through the upper partition and communicates with the middle chamber. A piston is slidably fitted axially inside the middle chamber, dividing it into a test chamber and a detection chamber. The upper chamber... An electric push rod is fixedly installed inside the chamber. The output end of the electric push rod extends into the middle chamber and is fixedly connected to the piston. A through hole is opened in the middle of the piston, and a venturi tube is fixedly installed inside the through hole. A one-way exhaust valve II is installed inside the venturi tube. The detection assembly includes a laser emitter and a laser receiver fixedly installed on the detector. The electric push rod, the laser emitter, and the laser receiver are all connected to the controller. Two mounting holes are symmetrically opened on the side wall of the detection chamber. The two mounting holes are concentrically arranged. The emitting end of the laser emitter and the receiving end of the laser receiver are respectively fixedly installed in the two mounting holes. An exhaust hole is opened on the lower partition, and a one-way exhaust valve III is installed inside the exhaust hole.

[0006] Preferably, the detector includes a cavity, a top plate bolted to the upper end of the cavity, and an exhaust pipe bolted to the lower end of the cavity. The exhaust pipe is a rotating body with a conical upper end and a cylindrical lower end.

[0007] Preferably, two ring platforms are fixedly installed at axial intervals inside the cavity. The cross-section of the two partitions is T-shaped, and the two partitions are bolted to the two ring platforms respectively.

[0008] Preferably, the top of the upper partition is provided with multiple through holes evenly distributed along the circumference. A fixed tube is fixedly fitted inside the through hole. A one-way exhaust valve I is fixedly installed inside the output end of the fixed tube. The fixed tube corresponds to the air inlet tube. A connecting hose is provided between the corresponding air inlet tube and the fixed tube. A threaded joint is threaded inside the air inlet tube. The two ends of the connecting hose are fixedly fitted onto the threaded joint and the fixed tube, respectively. A protective net is fixedly installed inside the exposed end of the threaded joint.

[0009] Preferably, the piston has an externally threaded tube threaded into its through hole, and a fixed plate is concentrically fitted inside the externally threaded tube. Multiple connecting rods are uniformly fixedly installed between the fixed plate and the externally threaded tube along the circumference. A through groove is opened in the middle of the upper partition plate, and the output end of the electric push rod extends through the through groove into the middle cavity and is fixedly connected to the fixed plate. The venturi tube is located below the externally threaded tube, and the one-way exhaust valve II is fixedly installed inside the output end of the venturi tube.

[0010] Preferably, the top of the lower partition plate has a concentric groove, and an elastic membrane is fixedly installed in the groove. The bottom of the lower partition plate has a concentric fixed ring, and a retaining ring is bolted to the lower end of the fixed ring. A push plate is slidably fitted inside the fixed ring along the axial direction. A spring is fitted inside the fixed ring between the push plate and the retaining ring. A connecting rod is concentrically fixedly installed on the top of the push plate, and a ball is fixedly installed on the top of the connecting rod. The bottom of the groove has a concentric slot communicating with the fixed ring, and the diameter of the slot is larger than the diameter of the ball.

[0011] Preferably, glass plates are fixedly installed in both mounting holes, and the inner end faces of the two glass plates are arc-shaped surfaces that match the inner wall of the cavity, and the radius of curvature of the arc-shaped surfaces is equal to that of the inner wall of the cavity, and the center of curvature is collinear with that of the inner wall of the cavity.

[0012] Beneficial effects: Compared with the prior art, this utility model provides a particulate matter concentration detection device with a unique structure and convenient use. It achieves "physical isolation between sampling and detection" by dividing the device into three chambers: "upper chamber drive - middle chamber sampling and detection - lower chamber exhaust". Combined with the linkage of piston and one-way valve, it avoids cross-contamination and solves the problem of low accuracy caused by the "integrated sampling and detection" of existing devices. In addition, the combination structure of "Venturi tube acceleration + umbrella-shaped elastic membrane guidance" makes the airflow after sampling stable and the particulate matter uniformly distributed, which solves the problem of low detection accuracy caused by particulate matter aggregation in traditional devices. Attached Figure Description

[0013] Figure 1 This is a three-dimensional front view schematic diagram of the structure of this utility model; Figure 2 This is a three-dimensional side view of the structure of this utility model; Figure 3 This is a cross-sectional schematic diagram of the structure of this utility model; Figure 4 This utility model Figure 3 Enlarged schematic diagram of the structure in area A; Figure 5 This utility model Figure 3 Enlarged schematic diagram of the structure in region B.

[0014] In the diagram: 1. Detector; 11. Cavity; 12. Top plate; 13. Exhaust pipe; 14. Inlet pipe; 15. Threaded connector; 16. Protective net; 17. Partition plate; 18. Fixing pipe; 19. One-way exhaust valve I; 110. Connecting hose; 111. Electric push rod; 112. Piston; 113. Fixing plate; 114. Connecting rod; 115. External threaded pipe; 116. Venturi tube; 117. One-way exhaust valve II; 118. Elastic membrane; 119. Fixing ring; 120. Spring; 121. Push plate; 122. Connecting rod; 123. Ball; 124. One-way exhaust valve III; 2. Detection assembly; 21. Glass plate; 22. Laser emitter; 23. Laser receiver; 3. Controller. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] Example 1: This Example 1 provides a particulate matter concentration detection device with a unique structure. Please refer to [link / reference]. Figure 1-5 As shown, the device includes a detector 1, a detection assembly 2 and a controller 3 fixedly mounted on the detector 1. The detector 1 includes a cavity 11, a top plate 12, an exhaust pipe 13 and a partition 17. The cavity 11 is a cylindrical hollow structure, serving as the mounting base for each component. The inner wall is smooth to reduce airflow disturbance. The top plate 12 is bolted to the upper end of the cavity 11 to seal the upper chamber and prevent external air leakage from affecting the negative pressure sampling effect. The exhaust pipe 13 is bolted to the lower end of the cavity 11 and has a rotating structure with a conical upper end and a cylindrical lower end. Nitrile rubber sealing rings are provided between the top plate 12 and the cavity 11, and between the exhaust pipe 13 and the cavity 11 to ensure airtightness.

[0017] There are two partitions 17, which are spaced apart along the axial direction of the cavity 11. Both partitions have a T-shaped cross-section. Two ring platforms are fixedly installed on the inner wall of the cavity 11 at corresponding positions. The partitions 17 are fastened to the ring platforms by bolts, dividing the detector 1 into an upper chamber, a middle chamber, and a lower chamber. Three to four air inlet pipes 14 are evenly fixedly installed on the outer side of the upper chamber along the circumference (the number can be adjusted according to the sampling efficiency). The air inlet pipes 14 are threaded with threaded connectors 15. A protective net 16 (preferably with a mesh size of 0.5-1mm) is fixedly installed on the exposed end of the threaded connector 15. This net can intercept large particles such as leaves and hair, preventing them from entering the pipe and clogging the one-way valve or contaminating the detection components.

[0018] Multiple through holes are evenly distributed around the top of the upper partition plate. A fixed tube 18 is fixedly installed inside each through hole. A one-way exhaust valve I 19 is fixedly installed inside the output end of the fixed tube 18, allowing only outside air to enter the middle chamber in one direction to prevent backflow of air when the middle chamber is pressurized. The other end of the fixed tube 18 is connected to the inner end of the threaded connector 15 through a connecting hose 110. An electric push rod 111 is installed in the upper chamber. The electric push rod 111 is bolted to the top plate 12 of the upper chamber. The output end extends downward along the axial direction of the cavity 11, passes through the through groove in the middle of the upper partition plate and enters the middle chamber. The electric push rod 111 is electrically connected to the controller 3 and can realize the extension and retraction of the output end according to the controller command to provide power for the piston movement.

[0019] A piston 112 is axially slidably mounted in the middle chamber. The outer wall of the piston 112 is tightly fitted with the inner wall of the middle chamber (gap ≤ 0.1mm), dividing the middle chamber into the upper test chamber and the lower detection chamber. A through hole is opened in the middle of the piston 112, and an external threaded tube 115 is threadedly fitted into the through hole of the piston 112 to achieve a detachable connection, which is convenient for later maintenance and replacement. A fixed plate 113 is concentrically fitted into the external threaded tube 115 and is fixedly connected to the external threaded tube 115 by 3-4 connecting rods 114 evenly distributed around the circumference. The output end of the electric push rod 111 is fixedly connected to the center of the fixed plate 113, which can drive the piston 112 to move up and down synchronously.

[0020] The venturi tube 116 is fixedly fitted into the through hole of the piston 112 below the external threaded tube 115. Its inner diameter first contracts and then expands along the airflow direction, which can accelerate the airflow speed and stabilize the airflow pattern. The output end of the venturi tube 116 is equipped with a one-way exhaust valve II 117, which only allows the air in the test chamber to enter the detection chamber in one direction, preventing the airflow in the detection chamber from flowing back to the test chamber.

[0021] The top of the lower partition plate has a concentric groove, and an elastic membrane 118 (preferably made of nitrile rubber with a thickness of 0.2-0.3mm) is fixedly installed in the groove, providing good elastic deformation capability; a fixing ring 119 is concentrically fixedly installed at the bottom of the lower partition plate, and a retaining ring is bolted to the lower end of the fixing ring 119, and a push plate 121 is slidably fitted inside it along the axial direction; a spring 120 is fitted inside the fixing ring 119 between the push plate 121 and the retaining ring, and the spring 120 is always in a pre-compressed state, which can push the push plate 121 upward; a connecting rod 122 is concentrically fixedly installed at the top of the push plate 121, and a ball 123 (preferably made of hard plastic) is fixedly installed at the top of the connecting rod 122.

[0022] The bottom of the lower partition groove has a slot that communicates with the fixing ring 119. The diameter of the slot is larger than the diameter of the ball 123, so that the ball 123 can pass through the slot and abut against the elastic membrane 118, forcing the elastic membrane 118 to form an "umbrella-shaped structure". The lower partition on the outside of the groove has an exhaust hole. A one-way exhaust valve III 124 is fixedly installed in the exhaust hole, allowing only the air after detection to enter the exhaust pipe 13 in one direction, preventing the airflow in the exhaust pipe from flowing back to the detection chamber.

[0023] The detection component 2 includes a laser emitter 22 and a laser receiver 23. Two concentric mounting holes are symmetrically opened on the detector 1. The emitting end of the laser emitter 22 and the receiving end of the laser receiver 23 are respectively sealed and fixed in the two mounting holes to ensure that the laser light path passes through the central area of ​​the detection cavity (the area where the particle distribution is most uniform). The laser emitter 22 is preferably a semiconductor laser emitter (wavelength 650nm), and the laser receiver 23 is preferably a photodiode. Both are electrically connected to the controller 3 and can start detection and provide feedback signals according to the controller's instructions.

[0024] The controller 3 uses a microcontroller (preferably STM32F103) as the core control unit, and is electrically connected to the electric push rod 111, the laser emitter 22, and the laser receiver 23. It can perform the following functions: First, it controls the extension and retraction of the electric push rod 111 to complete sampling and gas delivery; second, it receives the position signal of the electric push rod 111 (the trigger signal when the partition is on the top surface of the piston 112) and triggers the laser emitter 22 to emit laser; third, it receives the scattered light signal from the laser receiver 23, calculates the particulate matter concentration through the built-in algorithm, and outputs the detection results (which can be connected to a display screen or communication module to upload data).

[0025] Working principle: The controller 3 sends a command to the electric push rod 111, causing its output end to extend axially and drive the piston 112 to move downward synchronously. At this time, the volume of the test chamber above the middle chamber increases and the pressure decreases, forming a negative pressure. Under the action of negative pressure, the one-way exhaust valve I 19 in the air inlet pipe 14 opens, and the outside air passes through the protective net 16 (intercepting large particulate impurities), the threaded joint 15, the air inlet pipe 14, the connecting hose 110, and the fixed pipe 18 in sequence, and finally enters the test chamber to complete the air sampling.

[0026] After sampling is completed, the controller 3 commands the output end of the electric push rod 111 to retract, driving the piston 112 to move upward; the volume of the test chamber decreases and the pressure increases, the one-way exhaust valve I 19 closes (to prevent backflow of airflow), and the positive pressure in the test chamber causes the one-way exhaust valve II 117 in the venturi tube 116 to open; the air (containing particulate matter) in the test chamber is accelerated by the venturi tube 116 and enters the detection chamber below the middle chamber in a stable airflow form.

[0027] Under the pre-compression force of the spring 120, the push plate 121 always moves upward, causing the ball 123 at the top of the connecting rod 122 to pass through the slot of the lower partition and come into close contact with the elastic membrane 118. The elastic membrane 118 forms an umbrella-shaped structure under the pushing action of the ball 123. After the airflow ejected from the venturi tube 116 hits the surface of the umbrella-shaped elastic membrane 118, it spreads evenly in all directions along the arc surface of the elastic membrane 118, so that the particulate matter in the air is evenly distributed in the detection cavity (laser optical path area), avoiding detection errors caused by the accumulation of particulate matter.

[0028] When the top surface of piston 112 comes into close contact with the upper partition, electric push rod 111 triggers a position signal and transmits it to controller 3; controller 3 immediately instructs laser emitter 22 to emit a laser beam, which passes through the uniform particulate area in the detection cavity, and part of the laser beam is scattered by the particulate matter; laser receiver 23 receives the scattered light signal and converts it into an electrical signal, which is then transmitted to controller 3; controller 3 calculates the particulate matter concentration in the air using a built-in scattered light intensity-particulate matter concentration algorithm (based on Mie scattering theory), completing one detection; after the detection is completed, controller 3... The controller 3 controls the electric push rod 111 to extend again, and the piston 112 moves down until the piston 112 contacts the lower partition. At this time, the elastic diaphragm 118 returns to a flat state under the action of the piston 112. As the piston 112 moves down, the volume of the detection chamber decreases, and a positive pressure is formed inside. At this time, the one-way exhaust valve III 124 on the lower partition opens, and the air in the detection chamber passes through the one-way exhaust valve III 124 and the lower chamber in sequence, and is finally discharged from the exhaust pipe 13. At the same time, the volume of the chamber to be tested increases and a negative pressure is formed again, starting the next round of sampling, realizing "continuous cycle detection".

[0029] Example 2: Based on Example 1, Example 2 has a glass plate 21 fixedly installed in both concentric mounting holes of the detector 1. The glass plate 21 is made of high-transmittance quartz glass (transmittance ≥95%) to ensure that the laser beam can pass through without attenuation and without affecting the detection signal. The inner end face of the glass plate 21 (the end face facing the inner side of the detection cavity) is an arc-shaped surface that matches the inner wall of the cavity 11, and the radius of curvature of the arc-shaped surface is equal to the radius of curvature of the inner wall of the cavity 11 and the center of curvature is collinear. This design makes the inner end face of the glass plate 21 and the inner wall of the cavity 11 form a continuous and smooth curved surface, avoiding the formation of eddies in the airflow at the mounting hole and reducing the adhesion of particles on the surface of the glass plate. The glass plate 21 and the mounting hole are sealed with epoxy resin sealant, which not only ensures the airtightness of the detection cavity, but also prevents particles from entering from the gap of the mounting hole.

[0030] With the glass plate 21 in place, the emitting end of the laser emitter 22 and the receiving end of the laser receiver 23 are completely isolated outside the detection cavity, and the laser is transmitted only through the glass plate 21. Even if particles in the detection cavity come into contact with the glass plate 21, its arc-shaped inner end face can reduce the amount of particles adhering. Furthermore, the piston 112 can wipe the surface of the glass plate 21 to achieve cleaning when it moves up and down, without the need to disassemble the detection components, which significantly improves the long-term stability and maintenance convenience of the device.

[0031] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A particulate matter concentration detection device, comprising a detector (1) and a detection assembly (2) and a controller (3) fixedly mounted on the detector (1), characterized in that: The detector (1) is sealed at the top and has an exhaust pipe (13) at the bottom. Two partitions (17) are fixedly fitted inside the detector (1), dividing it into three chambers: upper, middle, and lower. Multiple air inlet pipes (14) are evenly fixedly installed around the outer side of the upper chamber. A one-way exhaust valve I (19) is installed inside each air inlet pipe (14). The other end of the air inlet pipe (14) passes through the upper partition and communicates with the middle chamber. A piston (112) is slidably fitted inside the middle chamber, dividing it into a test chamber and a detection chamber. An electric push rod (111) is fixedly installed inside the upper chamber. The output end of the electric push rod (111) extends into the middle chamber and is fixedly connected to the piston (112). A through hole is provided in the middle of the plug (112), and a venturi tube (116) is fixedly installed in the through hole. A one-way exhaust valve II (117) is provided in the venturi tube (116). The detection assembly (2) includes a laser emitter (22) and a laser receiver (23) fixedly installed on the detector (1). The electric push rod (111), the laser emitter (22) and the laser receiver (23) are all connected to the controller (3). Two mounting holes are symmetrically opened on the side wall of the detection cavity. The two mounting holes are concentrically arranged. The emitting end of the laser emitter (22) and the receiving end of the laser receiver (23) are respectively fixedly installed in the two mounting holes. An exhaust hole is provided on the lower partition, and a one-way exhaust valve III (124) is provided in the exhaust hole.

2. The particulate matter concentration detection device according to claim 1, characterized in that: The detector (1) includes a cavity (11), a top plate (12) bolted to the upper end of the cavity (11), and an exhaust pipe (13) bolted to the lower end of the cavity (11). The exhaust pipe (13) is a rotating body with a conical upper end and a cylindrical lower end.

3. The particulate matter concentration detection device according to claim 2, characterized in that: The cavity (11) contains two ring platforms fixedly installed at axial intervals. The cross-section of the two partitions (17) is T-shaped, and the two partitions (17) are bolted to the two ring platforms respectively.

4. The particulate matter concentration detection device according to claim 1, characterized in that: The top of the upper partition is evenly provided with multiple through holes along the circumference. A fixed tube (18) is fixedly fitted inside the through hole. A one-way exhaust valve I (19) is fixedly installed inside the output end of the fixed tube (18). The fixed tube (18) corresponds to the air inlet pipe (14) one by one. A connecting hose (110) is provided between the corresponding air inlet pipe (14) and the fixed tube (18). A threaded joint (15) is threaded inside the air inlet pipe (14). The two ends of the connecting hose (110) are fixedly fitted on the threaded joint (15) and the fixed tube (18) respectively. A protective net (16) is fixedly installed inside the exposed end of the threaded joint (15).

5. The particulate matter concentration detection device according to claim 1, characterized in that: The piston (112) has an external threaded tube (115) threaded inside its through hole. A fixed plate (113) is concentrically fitted inside the external threaded tube (115). Multiple connecting rods (114) are evenly fixedly installed between the fixed plate (113) and the external threaded tube (115) along the circumference. A through groove is opened in the middle of the upper partition. The output end of the electric push rod (111) extends through the through groove into the middle cavity and is fixedly connected to the fixed plate (113). The venturi tube (116) is located below the external threaded tube (115). The one-way exhaust valve II (117) is fixedly installed inside the output end of the venturi tube (116).

6. The particulate matter concentration detection device according to claim 1, characterized in that: The top of the lower partition plate has a concentric groove, and an elastic membrane (118) is fixedly installed in the groove. The bottom of the lower partition plate has a fixed ring (119) fixedly installed in the concentric groove. The lower end of the fixed ring (119) is bolted to a retaining ring. A push plate (121) is slidably fitted inside the fixed ring (119) along the axial direction. A spring (120) is fitted inside the fixed ring (119) between the push plate (121) and the retaining ring. A connecting rod (122) is fixedly installed in the top of the push plate (121). A ball (123) is fixedly installed in the top of the connecting rod (122). The bottom of the groove has a slot that communicates with the fixed ring (119). The diameter of the slot is larger than the diameter of the ball (123).

7. The particulate matter concentration detection device according to claim 1, characterized in that: Glass plates (21) are fixedly installed in both mounting holes. The inner end faces of the two glass plates (21) are arc-shaped surfaces that match the inner wall of the cavity (11), and the radius of curvature of the arc-shaped surfaces is equal to that of the inner wall of the cavity (11), and the curvature centers are collinear.

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