Low-concentration smoke dust and flue gas tester

Abstract

The invention discloses a low-concentration smoke dust and flue gas tester, and relates to the field of environmental monitoring, the low-concentration smoke dust and flue gas tester comprises a sampling head used for collecting flue gas and a suction assembly used for providing sampling power, and the sampling head is elastically provided with a baffle used for blocking a sampling opening of the sampling head; the sampling head is provided with a locking assembly used for fixing the position of the baffle, and the locking assembly is controlled to lock or unlock the position of the baffle based on the working state of the suction assembly. According to the low-concentration smoke dust and flue gas tester provided by the invention, in the process of inserting the smoke gun into the flue gas pipeline, the baffle plate is fixed at the position for blocking the sampling opening through the locking assembly, and after the sampling head reaches the sampling position and the suction assembly works, the locking assembly is controlled to unlock the baffle plate, so that the sampling head is locked. In this way, it can be guaranteed that no smoke enters the sampling head in the process that the smoke gun is inserted into the smoke pipeline, and therefore the smoke sampling accuracy can be improved.

Description

Technical Field

[0001] This invention relates to the field of environmental monitoring, specifically to a low-concentration smoke and dust gas tester. Background Technology

[0002] As is well known, low-concentration smoke and flue gas analyzers are instruments used to detect low concentrations of particulate matter and flue gas components in the environment or exhaust gases, playing an important role in the field of environmental monitoring.

[0003] For example, the Chinese patent document with authorization announcement number CN221631096U, announcement date August 30, 2024, and titled "Device for Simultaneous Sampling of Dust and Flue Gas," includes a flat elliptical tube. Fixed seats and connecting seats are respectively installed at both ends of the flat elliptical tube. A Pitot tube, a flue gas temperature probe, a flue gas sampling tube, and a filter paper tube are fixedly connected to the end of the connecting seat. A dust sampling filter cover is threadedly connected to the end of the flue gas sampling tube. A dust sampling head, a low-concentration sampling head, or an oil fume sampling head is placed at the end of the filter paper tube. A locking flange adapted to the filter paper tube is fitted around the periphery of the dust sampling head, low-concentration sampling head, or oil fume sampling head. The end of the dust sampling head, low-concentration sampling head, or oil fume sampling head is snapped into the locking flange. This utility model, through the threaded connection between the flue gas sampling tube and the dust sampling filter cover, facilitates the installation or replacement of a filter element inside the dust sampling filter cover, thereby using the filter element to filter the dust in the gas entering the flue gas sampling tube.

[0004] When sampling gas using a testing instrument, the smoke gun needs to be inserted into the flue gas duct. Since the sampling point inlet may come into contact with air from outside the duct or a thin airflow near the duct wall—gases that do not contain the target flue gas—this can dilute the actual sample. Furthermore, dust, condensation, and other impurities may accumulate near the duct inlet, causing the sampling port to directly absorb these substances, leading to distorted sample composition and affecting the accuracy of subsequent concentration, particle size, and other data. Therefore, before the sampling port reaches the sampling position, it needs to be positioned away from the direction of flue gas flow. Once the port reaches the sampling position, it should be rotated to align with the flue gas flow path so that the sampling port can directly collect flue gas that matches the actual operating conditions. However, this method can only minimize the entry of flue gas during the insertion of the smoke gun; it cannot completely block it, resulting in some inherent errors in the collected sample. Summary of the Invention

[0005] The purpose of this invention is to provide a low-concentration smoke and dust gas tester to overcome the above-mentioned shortcomings of the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A low-concentration smoke and dust gas tester includes a sampling head for collecting smoke and a suction assembly for providing sampling power. The sampling head is elastically provided with a baffle for sealing the sampling port of the sampling head.

[0008] The sampling head is equipped with a locking component for fixing the position of the baffle. The locking component is controlled to lock or unlock the position of the baffle based on the working state of the suction component.

[0009] The aforementioned low-concentration smoke and dust gas tester has two baffles and a rotating seat on the sampling head. The two baffles are rotatably connected to the two rotating seats respectively, and a first torsion spring is provided between the two baffles and the two rotating seats respectively.

[0010] The aforementioned low-concentration smoke and dust gas tester includes a locking component comprising a first locking rod elastically disposed on the sampling head, a first locking hole adapted to the first locking rod being provided on the baffle, the first locking rod being inserted into the first locking hole, and the first locking rod communicating with the internal space of the sampling head.

[0011] The aforementioned low-concentration smoke and dust gas tester has a side blocking plate installed on the sampling head.

[0012] In the aforementioned low-concentration smoke and dust gas tester, a transmission component is rotatably mounted on the sampling head, and multiple baffles are also rotatably mounted on the sampling head. Each of the multiple baffles is connected to the transmission component by a connecting rod, and a second torsion spring is provided between the transmission component and the sampling head.

[0013] The aforementioned low-concentration smoke and dust gas tester includes a locking component comprising a second locking rod elastically disposed on the sampling head, and a second locking hole adapted to the second locking rod on the transmission component, wherein the second locking rod is inserted into the second locking hole;

[0014] It also includes a power assembly for driving the second locking lever to move.

[0015] The aforementioned low-concentration smoke and dust gas tester includes a power component comprising a drive unit disposed on the second locking rod, a through hole communicating with the internal space of the sampling head, the drive unit being located inside the through hole, and a circular hole adapted to the through hole being disposed on the transmission component.

[0016] In the aforementioned low-concentration smoke and dust gas tester, the stroke of the transmission component is greater than the size of the circular hole.

[0017] The aforementioned low-concentration smoke and dust gas tester has multiple through holes.

[0018] The aforementioned low-concentration smoke and dust gas tester has a sampling head with a manifold inside, which is connected to multiple through holes.

[0019] In the above technical solution, the present invention provides a low-concentration smoke and flue gas tester, which flexibly sets a baffle and a locking component on the sampling port of the sampling head. During the process of inserting the smoke gun into the flue gas pipe, the locking component fixes the baffle in the position that blocks the sampling port. After the sampling head reaches the sampling position and the suction component operates, the locking component is controlled to unlock the baffle. In this way, it can be ensured that no smoke enters the inside of the sampling head during the process of inserting the smoke gun into the flue gas pipe, thereby improving the accuracy of flue gas sampling. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0021] Figure 1 This is a schematic diagram of the overall structure of the sampling head provided in an embodiment of the present invention;

[0022] Figure 2 This is a partial cross-sectional view of the sampling head provided in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the overall structure of the sampling head provided in another embodiment of the present invention;

[0024] Figure 4 This is a front view schematic diagram of the sampling head structure provided in another embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of the structure of the baffle in the open state according to another embodiment of the present invention;

[0026] Figure 6 This is a partial cross-sectional view of the sampling head provided in another embodiment of the present invention;

[0027] Figure 7 This is a schematic diagram of the overall structure of the transmission component provided in another embodiment of the present invention;

[0028] Figure 8 for Figure 6 Enlarged schematic diagram of a local structure at point A;

[0029] Figure 9 This is a schematic diagram of the structure of the second locking lever in the unlocked state, as provided in another embodiment of the present invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Sampling head; 2. Baffle; 3. Rotating seat; 4. First locking rod; 5. First locking hole; 6. First slide groove; 7. First spring; 8. Side blocking plate; 9. Transmission component; 901. Circular part; 902. Mounting part; 903. L-shaped rod; 10. Connecting rod; 11. Second torsion spring; 12. Second locking rod; 13. Second locking hole; 14. Driving part; 15. Through hole; 16. Circular hole; 17. Convergence part; 18. Hemispherical part; 19. Second slide groove; 20. Second spring. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] In the description of this invention, the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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 invention.

[0034] Reference Figure 1-9 This invention provides a low-concentration smoke and dust gas tester, including a sampling head 1 for collecting smoke and a suction assembly (not shown) for providing sampling power. The sampling head 1 is elastically provided with a baffle 2 for sealing the sampling port of the sampling head 1. The sampling head 1 is provided with a locking assembly for fixing the position of the baffle 2. The locking assembly is controlled to lock or unlock the position of the baffle 2 based on the working state of the suction assembly.

[0035] Specifically, the smoke and dust tester includes a sampling system, a pretreatment system, and a measurement system. Sampling head 1 is part of the sampling system, installed at the end of the smoke gun. The smoke gun contains a suction component such as an air pump to draw smoke from the flue into the smoke gun. Sampling points are set in the area of ​​the smoke emission to be measured, arranged radially along the pipe. During sampling, the smoke gun needs to be inserted into the flue. Since the sampling point inlet may come into contact with air outside the pipe or a thin airflow near the pipe's inner wall, these gases, lacking the target smoke and dust, will dilute the actual sample. Furthermore, dust, condensate, and other impurities may accumulate near the pipe inlet, easily causing the sampling port to directly adsorb these substances, leading to distorted sample composition and affecting the accuracy of subsequent concentration, particle size, and other data. Therefore, before the sampling port of the smoke gun reaches the sampling position, it needs to be positioned away from the direction of smoke flow. Once the sampling port reaches the sampling position, it is then rotated to face the direction of smoke flow. The process of sampling the smoke is carried out by providing power through the suction component. This is existing technology and will not be elaborated here. One of the core innovations of this invention is that the baffle 2 can be two semi-circular plate-shaped structures that are slidably arranged at the sampling port position. They are connected by elastic components such as springs, so that they tend to move away from each other. The locking component can be a pin shaft and pin hole mating structure. The purpose of this setting is that when the smoke gun is inserted into the smoke pipe, the baffle 2 is fixed in the position that blocks the sampling port by the locking component. When the sampling head 1 reaches the sampling position and the suction component has been working, the locking component is controlled to unlock the baffle 2. At this time, the elastic force of the elastic component that controls the movement of the baffle 2 is released, so that the two baffles 2 move away from each other to open the sampling port. Only then will smoke enter the sampling port. This can ensure that no smoke enters the sampling head 1 during the process of inserting the smoke gun into the smoke pipe, thereby improving the accuracy of smoke sampling.

[0036] As an alternative to the sliding arrangement of the baffles 2 described above, there are two baffles 2. The sampling head 1 is provided with a rotating seat 3. The two baffles 2 are rotatably connected to the two rotating seats 3 respectively, and a first torsion spring (not shown) is provided between the two baffles 2 and the two rotating seats 3 respectively. Specifically, a rotating shaft is provided inside the rotating seat 3, and a connecting part is provided on the baffle 2. The connecting part is provided with a rotating hole adapted to the rotating shaft. The first torsion spring is provided between the connecting part and the rotating seat 3, and the elastic force of the first torsion spring causes the two baffles 2 to have a tendency to rotate away from the sampling port. The purpose of this arrangement is that when the locking component locks the position of the baffles 2, the two baffles 2 block the sampling port. When the locking component is released, the elastic force of the first torsion spring is released, causing the two baffles 2 to rotate simultaneously away from the sampling port to open the sampling port.

[0037] Furthermore, the locking assembly includes a first locking rod 4 elastically disposed on the sampling head 1, and a first locking hole 5 adapted to the first locking rod 4 is provided on the baffle 2. The first locking rod 4 is inserted into the first locking hole 5, and the first locking rod 4 communicates with the internal space of the sampling head 1. Specifically, a first groove 6 is formed along the axial direction inside the side wall of the sampling head 1. The first locking rod 4 is slidably disposed inside the first groove 6. The elastic setting here means that a first spring 7 is provided between the first locking rod 4 and the first groove 6, and the first groove 6 is connected to the space inside the sampling head 1. The purpose of this arrangement is that the elastic force of the first spring 7 causes the first locking rod 4 to be inserted into the first locking hole 5. At this time, under the restriction of the first locking rod 4, the baffle 2 cannot rotate, thereby locking the baffle 2. When sampling is required, the sampling head 1 is first transported to the sampling position, and then the suction assembly is turned on. Since the sampling head 1 is in a blocked state, the suction assembly will create a negative pressure effect inside the sampling head 1. When the first locking rod 4 is subjected to negative pressure... When the force is greater than the elastic force of the first spring 7, it will pull the first locking rod 4 to slide into the first groove 6 and store force in the first spring 7. After the first locking rod 4 is pulled out from the first locking hole 5, the restriction effect of the first locking rod 4 on the baffle 2 disappears. At this time, the elastic force of the first torsion spring is released, thereby driving the two baffles 2 to rotate, so as to achieve the passive opening of the sampling port. After sampling is completed, the baffle 2 can be controlled to rotate in the opposite direction by mechanical equipment or manual means. During this process, the surface of the baffle 2 will abut against the first locking rod 4 and store force in the first spring 7. When the baffle 2 rotates to the position, the first locking hole 5 coincides with the first locking rod 4. At this time, the elastic force of the first spring 7 is released, thereby driving the first locking rod 4 to insert into the first locking hole 5, so as to achieve the reset of the baffle 2.

[0038] Furthermore, the sampling head 1 is provided with a side blocking plate 8. Specifically, in order to avoid interference during the rotation of the two baffles 2, the sides of the two baffles 2 that are close to each other are made into an arc shape. This creates a gap at the edge of the contact point between the two baffles 2, allowing flue gas to enter from this position and preventing the sampling port from being completely sealed. The side blocking plate 8 is a protruding structure on the end face of the sampling head 1, which is used to seal the gap between the two baffles 2, thereby improving the sealing performance of the sampling head 1.

[0039] It should be noted that in the above embodiments, if the negative pressure effect inside the sampling head 1 is unstable, or if the stiffness coefficients of the two second springs 20 are incorrect, a single first locking rod 4 may be pulled out of the first locking hole 5, while the other first locking rod 4 may not be pulled out of its corresponding first locking hole 5, resulting in the sampling port only opening halfway. As another embodiment of the present invention, a transmission member 9 is rotatably provided on the sampling head 1, and multiple baffles 2 are also rotatably provided on the sampling head 1. Each of the multiple baffles 2 is connected to the transmission member 9 by a connecting rod 10, and a second torsion spring 11 is provided between the transmission member 9 and the sampling head 1. Specifically, the transmission component 9 includes a ring portion 901 and a mounting portion 902, with the ring portion 901 and the mounting portion 902 connected by multiple L-shaped rods 903. An annular groove is formed on the outer circumferential surface of the sampling head 1, and the ring portion 901 is rotatably connected to the annular groove. Limiting structures such as limit strips are provided between the two to prevent them from disengaging. The baffle 2 is approximately fan-shaped, with a connecting hole inside. A protruding ring is provided at the end of the sampling head 1, and the baffle 2 is rotatably positioned at the position of the protruding ring through the connecting hole. After multiple baffles 2 are fitted together, the opening of the sampling head 1 is sealed. One end of the connecting rod 10 is rotatably mounted on the baffle 2, and the other end is rotatably mounted on the mounting portion 902. A second torsion spring 11 is disposed between the protruding ring and the ring portion 901, and the elastic force of the second torsion spring 11 causes the transmission component 9 to have a... Figure 4 The counterclockwise rotation trend shown is designed so that when the sampling head 1 reaches the sampling position, the locking component unlocks the baffle 2. At this time, the elastic force of the second torsion spring 11 is released, which drives the transmission component 9 to rotate counterclockwise. Thus, under the action of multiple connecting rods 10, multiple baffles 2 are pulled to rotate simultaneously away from the sampling port, so as to open the sampling port. The advantage of this design is that by controlling the rotation of the transmission component 9, the working state of multiple baffles 2 can be controlled simultaneously, thereby ensuring that the sampling port can be fully opened, so as to avoid the situation where only part of the sampling port is opened.

[0040] It should be noted that the above-mentioned method of opening the baffle 2 by drawing negative pressure may result in excessive suction at the moment the baffle 2 opens, causing a sudden increase in the air intake rate at the sampling port. This would not meet the requirement of isokinetic sampling (ensuring that the velocity of the dust-laden flue gas entering the sampling head 1 is approximately equal to the velocity of the flue gas at that point in the flue gas duct. This is because when the flue gas velocity at the measurement point is less than the velocity of the flue gas entering the sampling head 1, the measured dust concentration value is too low; when the flue gas velocity at the measurement point is greater than the velocity of the flue gas entering the sampling head 1, the measured dust concentration value is too high). Furthermore, the locking assembly includes a second locking rod 12 elastically disposed on the sampling head 1, and a second locking hole 13 adapted to the second locking rod 12 is provided on the transmission component 9, with the second locking rod 12 inserted into the second locking hole 13; it also includes a power component for driving the second locking rod 12 to move. The power assembly includes a drive unit 14 disposed on the second locking rod 12, a through hole 15 communicating with the internal space of the sampling head 1, the drive unit 14 being located inside the through hole 15, and a circular hole 16 adapted to the through hole 15 being disposed on the transmission member 9.Specifically, in this embodiment, there should be at least one second locking rod 12 and a second locking hole 13. A second sliding groove 19 is provided inside the side wall of the sampling head 1. A second spring 20 is elastically provided there, that is, a second locking rod 12 and a second sliding groove 19 are provided between them. The second locking rod 12 is L-shaped, including a horizontal section and a vertical section. The horizontal section is inserted into the second locking hole 13, and the vertical section is the driving part 14. The driving part 14 has a hollow area that allows gas to pass through. One end of the through hole 15 is connected to the internal space of the sampling head 1, and the other end can be connected to a constant pressure storage tank containing clean gas. The purpose of this design is that when the sampling head 1 is inserted into the sampling position, the suction assembly is activated. The suction assembly evacuates the space inside the sampling head 1, and the evacuated gas enters the sampling head 1 from the constant pressure storage tank and the through hole 15 to meet the suction requirements of the suction assembly. This avoids a negative pressure situation inside the sampling head 1. As the suction assembly gradually transitions from the initial activation state to the working state, its suction effect on the channel increases, resulting in a greater force on the drive unit 14. When the force received by the drive unit 14 exceeds the elastic force of the second spring 20, the second locking rod 1 will engage. 2. The entire assembly moves away from the second locking hole 13. After the second locking rod 12 is pulled out of the second locking hole 13, the baffle 2 is passively unlocked. The advantages of this setting are: firstly, the sampling head 1 is passively opened during the suction process of the suction assembly; secondly, after the sampling head 1 is passively opened, there will be no negative pressure inside the sampling head 1, so as to meet the requirement of isokinetic sampling as much as possible; thirdly, when the suction assembly is first started, the suction speed inside the sampling head 1 will be less than the gas flow speed inside the flue gas pipe. Therefore, in this application, when the suction assembly is first started... The baffle 2 will not open. Only when the force on the drive unit 14 is greater than the elastic force of the second spring 20, it indicates that the suction assembly is running stably. At this time, the sampling port will be passively opened to further meet the requirements of isokinetic sampling. Fourth, since the through hole 15 is only connected to the space inside the sampling head 1 and not to the space inside the flue gas duct, only the internal suction of the suction assembly can open the baffle 2. The airflow in the flue gas duct cannot open the baffle 2, so as to achieve the one-sided opening effect of the baffle 2, thereby avoiding the baffle 2 being opened accidentally due to the airflow in the flue gas duct.

[0041] Furthermore, the rotational stroke of the transmission member 9 is greater than the size of the circular hole 16. This arrangement ensures that, when not sampling, the circular hole 16 coincides with the through hole 15, allowing gas to pass through. When the transmission member 9 rotates to open the baffle 2, the main body of the annular portion 901 will fit against the through hole 15, thus sealing it. This minimizes the risk of gas entering the sampling head 1 through the through hole 15 during subsequent sampling.

[0042] Preferably, there are multiple through holes 15. The multiple through holes 15 are arranged in an array on the side wall of the sampling head 1, so as to provide multiple air intake channels inside the sampling head 1 to meet the air intake requirements of the suction component.

[0043] Furthermore, the sampling head 1 is provided with a manifold 17 inside, which communicates with multiple through holes 15. Specifically, the manifold 17 is an annular channel used to integrate multiple through holes 15 together, so as to facilitate communication between the multiple through holes 15 and the constant pressure storage tank.

[0044] Furthermore, the end of the second locking rod 12 is provided with a hemispherical portion 18, and the elastic force of the second torsion spring 11 is greater than the elastic force of the second spring 20. Specifically, the width of the inlet position of the through hole 15 is equal to the distance the second locking rod 12 moves. The purpose of this arrangement is that when the second locking rod 12 is inserted into the second locking hole 13, the hemispherical portion 18 of the second locking rod 12 is fully inserted into the second locking hole 13, and a portion of the horizontal section is also inserted into the second locking hole 13, so as to achieve its limiting effect on the transmission component 9. When the suction assembly pumps air to drive the second locking rod 12 to move, and when the portion of the horizontal section inserted into the second locking hole 13 is pulled out of the second locking hole 13, the spherical surface of the hemispherical portion 18 will move to the edge position of the second locking hole 13. At this time, the elastic force of the second torsion spring 11 will be reduced. The transmission component 9 will be released, causing it to rotate. When the transmission component 9 rotates, the edge of the second locking hole 13 will abut against the spherical surface of the hemisphere 18, thereby causing the hemisphere 18 and the second locking rod 12 to move further and store force on the second spring 20. This will cause the main body of the drive unit 14 to block the through hole 15, thus achieving a secondary sealing effect on the through hole 15. After sampling is completed, the transmission component 9 is controlled to rotate in the opposite direction to make the second locking hole 13 coincide with the second locking rod 12. At this time, the elastic force of the second spring 20 is released, thereby causing the second locking rod 12 to be inserted into the second locking hole 13 to complete the reset of the second locking rod 12.

[0045] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A low-concentration smoke and dust gas tester, comprising a sampling head for collecting smoke and a suction assembly for providing sampling power, characterized in that, The sampling head is elastically provided with a baffle for sealing the sampling port of the sampling head; The sampling head is equipped with a locking component for fixing the position of the baffle. The locking component is controlled to lock or unlock the position of the baffle based on the working state of the suction component.

2. The low-concentration smoke and dust gas tester according to claim 1, characterized in that, There are two baffles, and a rotating seat is provided on the sampling head. The two baffles are rotatably connected to the two rotating seats respectively, and a first torsion spring is provided between the two baffles and the two rotating seats respectively.

3. The low-concentration smoke and dust gas tester according to claim 2, characterized in that, The locking assembly includes a first locking rod elastically disposed on the sampling head, and a first locking hole adapted to the first locking rod is provided on the baffle. The first locking rod is inserted into the first locking hole, and the first locking rod communicates with the internal space of the sampling head.

4. The low-concentration smoke and dust gas tester according to claim 2, characterized in that, The sampling head is equipped with a side blocking plate.

5. A low-concentration smoke and dust gas tester according to claim 1, characterized in that, The sampling head is rotatably equipped with a transmission component, and the sampling head is also rotatably equipped with multiple baffles. Each of the multiple baffles is connected to the transmission component by a connecting rod, and a second torsion spring is provided between the transmission component and the sampling head.

6. The low-concentration smoke and dust gas tester according to claim 5, characterized in that, The locking assembly includes a second locking rod that is elastically disposed on the sampling head, and the transmission member has a second locking hole that is adapted to the second locking rod, and the second locking rod is inserted into the second locking hole; It also includes a power assembly for driving the second locking lever to move.

7. A low-concentration smoke and dust gas tester according to claim 6, characterized in that, The power assembly includes a drive unit disposed on the second locking rod, a through hole communicating with the internal space of the sampling head is provided on the sampling head, the drive unit is located inside the through hole, and a circular hole adapted to the through hole is provided on the transmission component.

8. A low-concentration smoke and dust gas tester according to claim 7, characterized in that, The rotational stroke of the transmission component is greater than the size of the circular hole.

9. A low-concentration smoke and dust gas tester according to claim 7, characterized in that, There are multiple through holes.

10. A low-concentration smoke and dust gas tester according to claim 9, characterized in that, The sampling head has a manifold inside, which is connected to multiple through holes.

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