Filter paper pressing assembly, sampling device and atmospheric particulate monitoring device

Abstract

The utility model discloses a filter paper pressing assembly, a sampling device and an atmospheric particulate monitoring device in the technical field of environmental quality monitoring instruments, which comprise a base, an upper unit body, a lower unit body and filter paper, wherein the upper unit body and the lower unit body are fixed on the base; the lower unit body comprises a fixed part, a movable part and a driving unit, the driving unit comprises a cam, a first driving piece, a first blocking piece and a first photoelectric switch, the first blocking piece and the cam are coaxially arranged, the first blocking piece and the cam synchronously rotate, at least two grooves are formed in the first blocking piece, and the first photoelectric switch is arranged in the grooves; the first optoelectronic switch determines the current position of the movable part by detecting the positions of the different grooves in the first blocking piece, and one first optoelectronic switch detects the positions of the different grooves in the first blocking piece, so that the current angle of the cam and the current position of the movable part are determined, the number of the optoelectronic switches is reduced, and the production cost is reduced. And the failure rate of the whole equipment is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of environmental quality monitoring instruments, in particular to a filter paper pressing component, a sampling device and an atmospheric particulate matter monitoring device. Background Art

[0002] Atmospheric particulate matter is a general term for various solid and liquid particulate matter in the atmosphere. According to their size, they can be divided into total suspended particulate matter (TSP), inhalable particulate matter (PM10) and fine particulate matter (PM2.5). Whether artificially or naturally generated, atmospheric particulate matter will have an impact on air quality and climate change that cannot be ignored. In particular, particulate matter with a diameter of 10μm or less (such as PM2.5 and PM10) plays an important role in this. Not only can it cause haze weather and reduced visibility, but it can also enter the body through the human respiratory tract, seriously endangering human health. The smaller the particle size, the deeper it enters the human respiratory tract. For example, particles with a particle size of less than 2μm can all directly enter the bronchioles and alveoli, which is more harmful to human health. Therefore, effective monitoring and evaluation of the concentration and composition of atmospheric particulate matter is an important measure to protect public health and environmental protection.

[0003] In order to achieve automatic quantitative monitoring of atmospheric particulate matter concentration and components, it is usually necessary to sample the particulate matter in the atmosphere first, and then test the sampled samples. In the sampling state, the particulate matter in the gas is enriched on the belt filter paper; when the next cycle of sampling is required, the control unit controls the movement of the filter paper, and the blank filter paper corresponding to the next cycle moves to the sampling area and is in a sampling state to prepare for the next cycle of sampling. In this process, the filter paper needs to be compressed by the filter paper compression assembly, and then the sample gas passes through the inner cavity of the compression assembly, and passes through the clamped filter paper while ensuring that the sample gas does not leak and the outside atmosphere does not interfere. When the filter paper needs to be moved, the compression assembly will loosen the filter paper to ensure that the filter paper can be moved at will.

[0004] For example, the Chinese utility model patent with authorization announcement number CN212471241 U discloses a filter paper pressing and releasing device for a β-ray atmospheric particulate matter monitor, in which a paper pressing plate for pressing the filter paper is driven by a cam, and the position of the cam is determined by two photoelectric switches in cooperation with a photoelectric switch baffle.

[0005] In the prior art, when determining the position of the cam, two photoelectric switches are used in conjunction with a photoelectric switch baffle. A groove is provided on the photoelectric switch baffle. When the cam rotates and drives the photoelectric switch baffle to rotate, the groove passes through the two photoelectric switches. The position of the cam is determined by detecting the position of the groove through the two photoelectric switches. The structure is relatively complex and the failure rate is relatively high.

[0006] Based on this, the utility model designs a filter paper pressing assembly, a sampling device and an atmospheric particulate matter monitoring device to solve the above problems. Utility Model Content

[0007] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a filter paper pressing assembly, comprising a base, an upper unit body fixed on the base, a lower unit body and filter paper passing through the upper unit body and the lower unit body, the lower unit body comprising a fixed part fixedly connected to the base, a movable part slidably matched with the fixed part and a driving unit for driving the movable part to move, the movement of the movable part cooperates with the upper unit body to realize a pressed state of the filter paper or a loosened state of the filter paper, the driving unit comprises a cam, a first driving member, a first baffle and a first photoelectric switch, the first driving member is used to drive the cam to rotate to drive the movable part to approach or move away from the upper unit body, the first baffle is coaxially arranged with the cam and rotates synchronously with the cam, at least two grooves are provided on the first baffle, the first photoelectric switch determines the current position of the movable part by detecting the positions of different grooves on the first baffle, thereby reducing the number of photoelectric switches, reducing production costs, and reducing the failure rate of the overall equipment.

[0008] As a further solution of the utility model, two grooves are provided on the first baffle, and the two grooves are arranged relatively to each other, respectively corresponding to the compressed state and the relaxed state of the movable part, and the opening widths or opening depths or shapes of the two grooves are different, so that the light transmission ranges of the two grooves are different.

[0009] As a further scheme of the utility model, the upper unit body includes an upper airway platform and an air intake pipe, the upper airway platform is fixed on the base, and in the compressed state, the upper airway platform contacts the upper surface of the filter paper through the bottom surface, one end of the air intake pipe is fixedly connected to the upper airway platform for conveying sample gas to the upper airway platform, the fixed part includes a lower airway platform and an exhaust pipe, the inner cavity of the lower airway platform is connected to the outside through the exhaust pipe for discharging the sample gas entering the lower airway platform from the upper airway platform; the movable part includes a lifting support seat and a support platform, the lifting support seat is slidably matched with the lower airway platform, a cavity is provided in the middle of the lifting support seat for accommodating a cam, and the lifting support seat is driven to move by the rotation of the cam, the support platform is fixed to the top of the lifting support seat, and in the compressed state, the top surface of the support platform contacts the lower surface of the filter paper.

[0010] As a further solution of the utility model, the inner cavity of the support platform is connected with the inner cavity of the lower airway platform, and a through hole connected with the inner cavity is provided on the top of the support platform, and a support bracket for supporting the filter paper to prevent deformation of the filter paper is installed in the through hole.

[0011] As a further solution of the utility model, a plurality of compression springs are fixedly installed between the support platform and the lower airway platform.

[0012] As a further solution of the utility model, a sealing ring is provided between the lower airway platform and the supporting platform.

[0013] A sampling device includes a filter paper pressing assembly and a belt control unit for controlling the movement of the filter paper. The belt control unit includes a supply wheel installed on a base for releasing the filter paper and a take-up wheel for taking up the filter paper. The supply wheel and the take-up wheel are driven by a second drive member and a third drive member respectively.

[0014] As a further solution of the utility model, two supporting wheels are fixedly mounted on the base, and the supporting wheels are arranged on the left and right sides of the lower unit body for supporting the filter paper and for maintaining the height of the filter paper when the movable part descends.

[0015] As a further solution of the utility model, a lifting wheel is slidably installed on the base, and the filter paper released by the pulley passes under the lifting wheel and contacts the supporting wheel. A second photoelectric switch and a limit device for limiting the up and down movement position of the lifting wheel are also installed on the base. The position of the lifting wheel is determined by the second photoelectric switch.

[0016] As a further solution of the utility model, the limiting device is a guide groove opened on the base, the lifting wheel is slidably arranged in the guide groove, and a second baffle is fixedly arranged on the lifting wheel. The position of the lifting wheel is determined by detecting the position of the second baffle by two second photoelectric switches fixed on the base.

[0017] As a further solution of the utility model, the limiting device is a swing arm rotatably arranged on the base, the lifting wheel is arranged at one end of the swing arm away from the rotation axis, the lifting wheel will drive the swing arm to rotate when it is raised or lowered, and a second baffle is fixedly arranged on the swing arm or the lifting wheel. The position of the second baffle is detected by two second photoelectric switches fixedly installed on the base to determine the current position of the lifting wheel.

[0018] An atmospheric particle monitoring device comprises an atmospheric particle sampling device, wherein a detector is fixedly arranged on the upper airway platform, and the detector is used to detect the particle sample to be tested collected on the filter paper.

[0019] The utility model has the following beneficial effects:

[0020] The device opens two grooves on the first baffle, and the opening widths of the two grooves are different. Thus, when the two grooves pass through the first photoelectric switch, the widths of the light beams received by the first photoelectric switch receiver are different. The two states of the cam are distinguished by the difference in light beam widths. In this way, the two states of the cam can be determined with only one photoelectric switch, thereby reducing the use of photoelectric switches, reducing the overall production cost, and reducing the failure rate of the equipment during subsequent use.

[0021] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0023] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0024] Figure 2 It is a rear view schematic diagram of the overall structure of the utility model.

[0025] Figure 3 It is a structural schematic diagram of the clamping assembly in the utility model.

[0026] Figure 4 for Figure 3 Schematic diagram of the enlarged structure of part A.

[0027] Figure 5 It is a schematic diagram of the cross-sectional structure of the clamping assembly in the utility model.

[0028] Legend:

[0029] 1. Base; 2. Filter paper; 31. Cam; 32. First driving member; 33. First baffle; 331. Groove; 34. First photoelectric switch; 41. Upper airway platform; 42. Inlet duct; 43. Detector; 51. Lower airway platform; 52. Exhaust duct; 53. Lifting support seat; 54. Support platform; 6. Compression spring; 7. Sealing ring; 81. Supply wheel; 82. Take-up wheel; 83. Second driving member; 84. Third driving member; 9. Support wheel; 101. Lifting wheel; 102. Swing arm; 103. Second baffle; 104. Second photoelectric switch. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. However, the present invention can be implemented in a variety of different ways as defined and covered below.

[0031] See also Figure 1-5 The utility model provides a technical solution: a filter paper pressing assembly, including a base 1, an upper unit body fixed on the base 1, a lower unit body fixed on the base 1, and filter paper 2 passing through the upper unit body and the lower unit body, the lower unit body includes a fixed part fixedly connected to the base 1, a movable part slidably matched with the fixed part, and a driving unit for driving the movable part to move, and the movable part moves and cooperates with the upper unit body to realize the pressing state of the filter paper 2 or the loosening state of the filter paper 2, the driving unit includes a cam 31, a first driving member 32, a first baffle 33 and a first photoelectric switch 34, the first The driving member 32 is used to drive the cam 31 to rotate so as to drive the movable part to move closer to or away from the upper unit body. The first baffle 33 is coaxially arranged with the cam 31 and rotates synchronously with the cam 31. At least two grooves 331 are provided on the first baffle 33. The first photoelectric switch 34 determines the current position of the movable part by detecting the position of the grooves 331 on the first baffle 33. The positions of different grooves 331 on the first baffle 33 are detected by a first photoelectric switch 34 to determine the current angle of the cam 31 and the current position of the movable part, thereby reducing the number of photoelectric switches, reducing production costs, and reducing the failure rate of the overall equipment.

[0032] Specifically, the upper unit body and the lower unit body are mounted on the base 1 relative to each other up and down, the cam 31 is mounted on the base 1, and the first driving member 32 is mounted on the base 1 to drive the cam 31 to rotate. Preferably, the first driving member 32 is mounted on the side of the base 1 facing away from the cam 31. Such a configuration makes the arrangement of components more compact and beautiful. The movable part is driven to rise or fall by the rotation of the cam 31, and the fixed upper unit body is cooperated to achieve a compressed state or a relaxed state. When the first driving member 32 drives the cam 31 to rotate, the first baffle 33 fixed on the surface of the cam 31 or on the output shaft of the first driving member 32 will rotate synchronously with the cam 31. The first photoelectric switch 34 is fixedly mounted on the fixed part or the base, and the first baffle 33 is located at the first photoelectric switch 34. The physical part of the first baffle 33 is used to block the light signal emitted by the transmitter of the first photoelectric switch 34. Only when the groove 331 of the first baffle 33 is rotated to between the transmitter and the receiver of the first photoelectric switch 34, the receiver can receive the light signal emitted by the transmitter. Each groove 331 on the first baffle 33 corresponds to a state of the cam 31. When the first photoelectric switch 34 detects the groove 331, it means that the cam 31 is at the angle corresponding to the current groove 331, so as to achieve the effect of determining the angle of the cam 31 and the position of the active part by a first photoelectric switch 34, reduce the number of photoelectric switches required to determine the position of the active part, reduce the manufacturing cost, and also reduce the failure rate of the overall device.

[0033] Preferably, Figure 5 As shown, two grooves 331 are provided on the first baffle 33, and the two grooves 331 are arranged opposite to each other, respectively corresponding to the compressed state and the relaxed state of the movable part. Since it is only necessary to determine whether the movable part is in the compressed state or the relaxed state during operation, two grooves 331 are provided on the surface of the first baffle 33, and the two grooves 331 are arranged opposite to each other, respectively corresponding to the above two states. A first photoelectric switch 34 cooperates with the two grooves 331 provided on the first baffle 33 to realize the state determination of the movable part.

[0034] Preferably, Figure 5 As shown, the opening widths or opening depths or shapes of the two grooves 331 are different, so that the light transmission ranges of the two grooves 331 are different, that is, the ranges of the light beams received by the receivers of the first photoelectric switch 34 are different. The first photoelectric switch 34 can accurately distinguish the two grooves 331 by the range or shape of the light beam, thereby further improving the accuracy of the detection. When the first driving member 32 or the instrument is restarted after a fault is repaired and the equipment resumes operation, it will not affect the accuracy of the first photoelectric switch 34 in detecting the position of the movable part.

[0035] like Figure 1-5 As shown, the upper unit body includes an upper airway platform 41 and an air inlet pipe 42, the upper airway platform 41 is fixed on the base 1, and in the compressed state, the upper airway platform 41 contacts the upper surface of the filter paper 2 through the bottom surface, one end of the air inlet pipe 42 is fixedly connected to the upper airway platform 41 for conveying sample gas to the upper airway platform 41, the fixed part includes a lower airway platform 51 and an exhaust pipe 52, the inner cavity of the lower airway platform 51 is connected to the outside through the exhaust pipe 52 for discharging the sample gas entering the lower airway platform 51 from the upper airway platform 41, the movable part includes a lifting support seat 53 and a support platform 54, the lifting support seat 53 is slidably matched with the lower airway platform 51, a cavity is provided in the middle of the lifting support seat 53 for accommodating the cam 31, and the lifting support seat 53 is driven to move by the rotation of the cam 31, the support platform 54 is fixed to the top of the lifting support seat 53, and in the compressed state, the top surface of the support platform 54 contacts the lower surface of the filter paper 2;

[0036] In this embodiment, the lifting support seat 53 is driven to move by the rotation of the cam 31, and the lifting support seat 53 drives the support platform 54 to move, while the upper airway platform 41 is fixedly installed on the base 1 and fixed in a fixed position. The lifting support seat 53 drives the support platform 54 to rise, and the upper airway platform 41 can be used to press the filter paper 2 to achieve a pressed state, and the lifting support seat 53 drives the support platform 54 to descend to release the filter paper 2 to achieve a relaxed state. A chamber is provided in the lifting support seat 53, and the cam 31 is arranged in the chamber of the lifting support seat 53. When the cam 31 rotates, it will contact the inner wall of the chamber of the lifting support seat 53 and drive the lifting support seat 53 to move.

[0037] Specifically, the lifting support seat 53 is fixedly connected to the support platform 54 via a connecting shaft, and a sliding rail is provided on the lower airway platform to accommodate the connecting shaft, so as to achieve sliding cooperation between the lifting support seat 53 and the lower airway platform 51.

[0038] Preferably, the lifting support seat 53 is fixedly connected to the support platform 54 through a plurality of connecting shafts, and the connecting shafts are symmetrically distributed. With such an arrangement, when the filter paper is in a compressed state, the compression force applied by the support platform to the filter paper is more evenly distributed, and the sealing effect is better.

[0039] The inner cavity of the support platform 54 is connected to the inner cavity of the lower airway platform 51, and a through hole connected to the inner cavity is provided on the top of the support platform 54, and a support bracket for supporting the filter paper 2 to prevent the filter paper 2 from deforming is installed in the through hole.

[0040] In this embodiment, the inner cavity of the support platform 54 is connected to the inner cavity of the lower airway platform 51, and a through hole is opened at the top of the support platform 54 to connect with the inner cavity. When in a compressed state, the sample gas entering the upper airway platform 41 from the air inlet pipe 42 will pass through the filter paper 2 and then enter its inner cavity through the through hole opened in the support platform 54, and finally enter the inner cavity of the lower airway platform 51 from the inner cavity of the support platform 54 and then be discharged from the exhaust pipe 52, so that the particulate matter in the sample gas is trapped on the filter paper to realize the collection of atmospheric particulate matter.

[0041] like Figure 5 As shown, a plurality of compression springs 6 are fixedly installed between the support platform 54 and the lower airway platform 51 .

[0042] Specifically, installation grooves for installing the compression spring 6 are provided on the opposite sides of the lower air duct platform 51 and the support platform 54. The two ends of the compression spring 6 are respectively arranged in the installation grooves provided on the lower air duct platform 51 and the support platform 54. The compression spring 6 is used to provide an upward elastic force for the support platform 54, apply a compression force to the support platform 54, and maintain the sealing effect between the support platform 54 and the upper air duct platform 41.

[0043] like Figure 4 As shown, a sealing ring 7 is provided between the lower airway platform 51 and the support platform 54 to increase the sealing effect of the lower airway platform 51 and the inner cavity of the support platform 54. Preferably, the sealing ring 7 is provided on the side wall sealing surface between the lower airway platform 51 and the support platform 54, and the deformation of the sealing ring 7 is reduced through the side sealing method, the service life of the sealing ring 7 is extended, and the reliability of the device is further improved.

[0044] like Figure 1-2As shown, a sampling device includes a filter paper pressing assembly and a belt control unit for controlling the movement of the filter paper 2. The belt control unit includes a supply wheel 81 installed on a base 1 for releasing the filter paper 2 and a take-up wheel 82 for taking up the filter paper 2. The supply wheel 81 and the take-up wheel 82 are driven by a second drive member 83 and a third drive member 84 respectively.

[0045] In this embodiment, the supply pulley 81 and the take-up pulley 82 are driven by the second driving member 83 and the third driving member 84 respectively, and the movement of the filter paper 2 is achieved by the cooperation of the supply pulley 81 and the take-up pulley 82. The second driving member 83 and the third driving member 84 are fixed on the base 1, and the supply pulley 81 and the unwinding pulley 82 are rotatably arranged on the base 1. When the filter paper is in a relaxed state, the filter paper 2 can be moved, so that the used filter paper 2 leaves from between the upper unit body and the lower unit body, and the unused filter paper 2 enters between the upper unit body and the lower unit body, and the continuous automatic sampling of atmospheric particulate matter is achieved by the belt control unit cooperating with the filter paper pressing assembly.

[0046] like Figure 1 As shown, two supporting wheels 9 are fixedly mounted on the base 1. The supporting wheels 9 are arranged on the left and right sides of the lower unit body for supporting the filter paper 2 and for maintaining the height of the filter paper 2 when the movable part descends.

[0047] In this embodiment, support wheels 9 are provided on both sides of the lower unit body. The height of the contact position between the support wheel 9 and the filter paper 2 is the same as the height of the top surface of the support platform 54 in the compressed state. In this way, after the support platform 54 is lowered, the filter paper 2 can also be maintained at the current height through the support wheel 9.

[0048] like Figure 1-2 As shown, a lifting wheel 101 is slidably mounted on the base 1, and the filter paper 2 released by the belt pulley 81 passes under the lifting wheel 101 and contacts the supporting wheel 9. A second photoelectric switch 104 and a limit device for limiting the upward and downward movement of the lifting wheel 101 are also mounted on the base 1. The position of the lifting wheel 101 is determined by the second photoelectric switch 104.

[0049] In this embodiment, when the supply wheel 81 releases the tape and the take-up wheel 82 takes up the tape in the relaxed state, it is necessary to ensure the accuracy of the tape release and the tape take-up. Therefore, the lifting wheel 101 is slidably installed on the base 1, and the filter paper 2 released by the supply wheel 81 passes under the lifting wheel 101 and contacts the support wheel 9. In the relaxed state, the tape is first released through the supply wheel 81. At this time, since the take-up wheel 82 has not started to take up the tape, the length of the filter paper 2 between the supply wheel 81 and the take-up wheel 82 will increase. At this time, the lifting wheel 101 will start to descend under the action of gravity. When the lifting wheel 101 descends to the lowest limit position, the second photoelectric switch 104 will detect that the lifting wheel 1 01, at this time, the supply wheel 81 immediately stops unwinding, and then the take-up wheel 82 starts to take up the tape. Since the supply wheel 81 is stationary at this time, the take-up wheel 82 takes up the filter paper 2 between the supply wheel 81 and the take-up wheel 82, so that the length of the filter paper 2 between the supply wheel 81 and the take-up wheel 82 is shortened. At this time, the filter paper 2 lifts the lifting wheel 101 upwards, and when the lifting wheel 101 is lifted to the highest limit position, the second photoelectric switch 104 detects the position of the lifting wheel 101, and the take-up wheel 82 stops rotating immediately. The unwinding and take-up of the tape are controlled by the movement of the lifting wheel 101, ensuring that the unwinding and take-up of the tape are accurate enough, and the structure is simple and easy to control.

[0050] Specifically, the limiting device is a guide groove opened on the base 1, and the lifting wheel 101 is slidably set in the guide groove. A second baffle 103 is fixedly set on the lifting wheel 101. The position of the lifting wheel 101 is determined by detecting the position of the second baffle 103 through two second photoelectric switches 104 fixed on the base 1.

[0051] The lifting wheel 101 will rise or fall along the guide groove. When the lifting wheel 101 rises to the highest limit position or falls to the lowest limit position, the second baffle 103 fixed on the lifting wheel 101 will respectively enter between the receiver and the transmitter of the two second photoelectric switches 104 arranged at intervals above and below, so as to determine the position of the lifting wheel 101. The overall structure is simple and easy to control.

[0052] like Figure 2 As shown, the limiting device is a swing arm 102 arranged on the base 1, and the lifting wheel 101 is arranged at one end of the swing arm 102 away from the rotation axis. When the lifting wheel 101 is raised or lowered, it will drive the swing arm 102 to rotate. A second baffle 103 is fixedly provided on the swing arm 102 or the lifting wheel 101, and the position of the second baffle 103 is detected by two second photoelectric switches 104 fixedly installed on the base 1 to determine the current position of the lifting wheel 101.

[0053] In this embodiment, the tape is first released through the supply wheel 81. At this time, since the take-up wheel 82 has not started to take up the tape, the length of the filter paper 2 between the supply wheel 81 and the take-up wheel 82 will increase. At this time, the lifting wheel 101 will start to descend under the action of gravity. When the lifting wheel 101 descends, it will drive the swing arm 102 and the second baffle 103 on the swing arm 102 to rotate. When the lifting wheel 101 descends to the lowest position, the second baffle 103 just swings between the transmitter and the receiver of one of the two second photoelectric switches 104. At this time, the supply wheel 81 immediately stops releasing the tape, and then the take-up wheel 82 starts to take up the tape. At this time The supply wheel 81 is stationary, and the filter paper 2 between the supply wheel 81 and the take-up wheel 82 is taken up by the take-up wheel 82, so that the length of the filter paper 2 between the supply wheel 81 and the take-up wheel 82 is shortened. As the length of the filter paper 2 is shortened, the lifting wheel 101 can be lifted upward by the filter paper 2. At this time, the lifting wheel 101 will drive the swing arm 102 and the second baffle 103 to rotate in the opposite direction. When the second baffle 103 rotates to between the transmitter and the receiver of another second photoelectric switch 104, the take-up wheel 82 stops rotating. The tape unwinding and take-up are controlled by the movement of the lifting wheel 101, ensuring that the tape unwinding and take-up are sufficiently accurate, and the structure is simple and easy to control.

[0054] An atmospheric particulate matter monitoring device includes a sampling device. A detector 43 is fixedly arranged on an upper airway platform 41. The detector 43 is used to detect the particle sample to be tested collected on the filter paper. The detector 43 cooperates with the sampling device to realize continuous monitoring of atmospheric particulate matter.

[0055] Specifically, the first driving member 32, the second driving member 83 and the third driving member 84 all use motors to drive the cam, the supply pulley and the take-up pulley to rotate.

[0056] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A filter paper pressing assembly, comprising a base (1), an upper unit body fixed on the base (1), a lower unit body fixed on the base (1), and filter paper (2) passing between the upper unit body and the lower unit body, wherein the lower unit body comprises a fixed part fixedly connected to the base (1), a movable part slidably matched with the fixed part, and a driving unit for driving the movable part to move, wherein the movable part moves in cooperation with the upper unit body to realize a pressed state of pressing the filter paper (2) or a loose state of releasing the filter paper (2), and wherein: The driving unit comprises a cam (31), a first driving member (32), a first baffle (33) and a first photoelectric switch (34); the first driving member (32) is used to drive the cam (31) to rotate so as to drive the movable part to approach or move away from the upper unit body; the first baffle (33) is coaxially arranged with the cam (31) and rotates synchronously with the cam (31); at least two grooves (331) are formed on the first baffle (33); and the first photoelectric switch (34) determines the current position of the movable part by detecting the positions of different grooves (331) on the first baffle (33).

2. A filter paper pressing assembly according to claim 1, characterized in that: Two grooves (331) are provided on the surface of the first baffle (33), and the two grooves (331) are arranged opposite to each other and correspond to the compressed state and the relaxed state of the movable part respectively. The opening widths or opening depths or shapes of the two grooves (331) are different, so that the light transmission ranges of the two grooves (331) are different.

3. The filter paper pressing assembly according to claim 1, characterized in that: The upper unit body comprises an upper airway platform (41) and an air inlet pipe (42); the upper airway platform (41) is fixed on the base (1); in a compressed state, the upper airway platform (41) contacts the upper surface of the filter paper (2) through the bottom surface; one end of the air inlet pipe (42) is fixedly connected to the upper airway platform (41) for conveying sample gas to the upper airway platform (41); The fixing part comprises a lower airway platform (51) and an exhaust pipe (52); the inner cavity of the lower airway platform (51) is connected to the outside through the exhaust pipe (52) for exhausting the sample gas entering the lower airway platform (51) from the upper airway platform (41); The movable part comprises a lifting support seat (53) and a support platform (54). The lifting support seat (53) is slidably matched with the lower airway platform (51). A cavity is provided in the middle of the lifting support seat (53) for accommodating the cam (31). The lifting support seat (53) is driven to move by the rotation of the cam (31). The support platform (54) is fixed to the top of the lifting support seat (53). In the compressed state, the top surface of the support platform (54) contacts the lower surface of the filter paper (2).

4. A filter paper pressing assembly according to claim 3, characterized in that: A plurality of compression springs (6) are fixedly installed between the support platform (54) and the lower airway platform (51).

5. A sampling device, comprising the filter paper pressing assembly according to any one of claims 1 to 4, characterized in that: The invention also comprises a belt control unit for controlling the movement of the filter paper (2), wherein the belt control unit comprises a belt supply wheel (81) mounted on the base (1) for releasing the filter paper (2) and a belt take-up wheel (82) for taking up the filter paper (2), wherein the belt supply wheel (81) and the belt take-up wheel (82) are driven by a second driving member (83) and a third driving member (84) respectively.

6. A sampling device according to claim 5, characterized in that: Two supporting wheels (9) are fixedly mounted on the base (1). The supporting wheels (9) are arranged on the left and right sides of the lower unit body and are used to support the filter paper (2) and to maintain the height of the filter paper (2) when the movable part descends.

7. A sampling device according to claim 5, characterized in that: A lifting wheel (101) is slidably mounted on the base (1), and the filter paper (2) released by the belt pulley (81) passes under the lifting wheel (101) and contacts the supporting wheel (9). A second photoelectric switch (104) and a limit device for limiting the upward and downward movement of the lifting wheel (101) are also mounted on the base (1), and the position of the lifting wheel (101) is determined by the second photoelectric switch (104).

8. A sampling device according to claim 7, characterized in that: The limiting device is a guide groove provided on the base (1), the lifting wheel (101) is slidably arranged in the guide groove, a second baffle (103) is fixedly arranged on the lifting wheel (101), and the position of the lifting wheel (101) is determined by detecting the position of the second baffle (103) through two second photoelectric switches (104) fixedly arranged on the base (1).

9. A sampling device according to claim 7, characterized in that: The limiting device is a swing arm (102) arranged on the base (1); the lifting wheel (101) is arranged at one end of the swing arm (102) away from the rotation axis; when the lifting wheel (101) is raised or lowered, it drives the swing arm (102) to rotate; a second baffle (103) is fixedly arranged on the swing arm (102) or the lifting wheel (101); and the current position of the lifting wheel (101) is determined by detecting the position of the second baffle (103) through two second photoelectric switches (104) fixedly installed on the base (1).

10. An atmospheric particulate matter monitoring device, comprising the sampling device according to any one of claims 5 to 9, characterized in that: A detector (43) is fixedly arranged on the upper airway platform (41), and the detector (43) is used to detect the particle sample to be detected collected on the filter paper (2).

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