A filter membrane filtration method atmospheric sampling module

Abstract

The present application relates to the technical fields of environmental atmosphere sampling, in particular to a filter membrane filtering method atmospheric sampling module, which is used to solve the problem of poor effect of the existing atmospheric sampling device, the module comprises a box body, a sampling head base is installed on the upper part of the box body, a hole is formed on the sampling head base, a supporting net is fixedly connected in the hole, and a filter membrane is placed on the supporting net; a mass flow meter and a fan are installed in the box body, an air inlet pipe is installed on the top of the mass flow meter, the air inlet pipe is communicated with the sampling head base, and the air inlet end of the fan is communicated with the mass flow meter; the initial operation voltage of the fan is obtained by the upper module to detect the flow value error of the certificate, and the positive and negative feedback of the voltage is given according to the built-in voltage-air volume curve obtained by testing the fan to calibrate the flow of the initial operation, and the real-time operation voltage of the fan is calibrated by the flow real-time comparison calibration algorithm; the module realizes the improvement of the sampling precision through the flow real-time comparison and the tail flow control.

Description

Technical Field

[0001] The present invention relates to the technical field of ambient atmospheric sampling, in particular to an atmospheric sampling module based on filter membrane filtration method. Background Art

[0002] In the field of environmental detection, as a common means of concentrated sampling, atmospheric samplers based on filter membrane filtration method are often used in atmospheric sampling processes. Currently, similar atmospheric samplers generally have problems such as large volume, high noise, low sampling accuracy, and increased exhaust gas temperature under large flow rates, which cannot meet the requirements of high-quality development in the field of environmental detection. Summary of the Invention

[0003] The present invention provides an atmospheric sampling module based on filter membrane filtration method to solve the problem of poor performance of existing atmospheric sampling devices.

[0004] To alleviate the above technical problems, the technical solution provided by the present invention is:[

[0005] An atmospheric sampling module based on filter membrane filtration method, comprising a box body, wherein a sampling head base is installed on the upper part of the box body, a hole is opened on the sampling head base, a support net is fixedly connected in the hole, and a filter membrane is placed on the support net;

[0006] A mass flow meter and a fan are installed in the box body, an air inlet pipe is installed on the top of the mass flow meter, the air inlet pipe is communicated with the sampling head base, and the air inlet end of the fan is communicated with the mass flow meter;

[0007] The initial operating voltage of the fan is obtained by an upper module from the flow indication error of the verification certificate, and positive and negative voltage feedback is given according to the built-in voltage-air volume curve obtained by testing the fan to perform flow calibration for initial operation, and

[0008] The real-time operating voltage of the fan is calibrated by a real-time flow comparison calibration algorithm.

[0009] Furthermore, the real-time flow comparison calibration algorithm comprises: obtaining a theoretical flow volume of Z L according to the formula X*Y=Z;

[0010] wherein, X represents the set flow, the unit is LPM, and Y represents the operating duration, the unit is min;

[0011] obtaining the actual volume measured by the mass flow meter as A L;

[0012] judging the magnitude relationship between A and Z: when A>Z, reducing the voltage of the fan; when A<Z, increasing the voltage of the fan; when A=Z, maintaining the voltage of the fan.

[0013] Furthermore, setting the atmospheric sampling volume as Z, when the atmospheric sampling volume is close to Z, the operation of the fan is controlled by a wake control algorithm to reduce the wake. The wake control algorithm includes...

[0014] The volume reaching the wake time period is set as (ZZ / T)L, where T represents the sampling duration;

[0015] When the sampling volume reaches (ZZ / T)L, but does not reach one-tenth of the final total sampling volume Z, the voltage of the fan is gradually reduced, and...

[0016] When the final sampling volume Z is reached to one-tenth, the power supply to the fan is cut off, and the fan is started and stopped by pulse power supply until the final sampling volume approaches the set volume Z.

[0017] Furthermore, the housing includes an inner frame, on the outside of which eight panels are mounted. The sampling head base is mounted on the upper panel, and a paperweight ring is hinged to the sampling head base. The paperweight ring is swayable and magnetically attached to the sampling head base.

[0018] Furthermore, a silencer box is fixedly connected inside the housing, and the air outlet of the fan is connected to the silencer box through an air duct. An exhaust port is provided at the bottom of the silencer box, and a second ventilation slot that cooperates with the exhaust port is provided on the bottom panel of the housing.

[0019] Furthermore, a heat dissipation fin is fixedly connected inside the housing, and a controller circuit is connected to the heat dissipation fin. The controller circuit is connected to a magnetic signal and power interface.

[0020] Furthermore, a cooling fan is installed inside the housing, the cooling fan is located above the heat dissipation fins, and the upper panel of the housing has a heat dissipation opening that cooperates with the cooling fan.

[0021] Furthermore, two support nets are installed on the sampling head base, and filter membranes are placed on both support nets. There are two air inlet pipes, which are respectively located at the lower part of the two support nets and connected by a switching pipe. A valve body is installed in the switching pipe. When the permeability of the filter membrane on one of the support nets decreases, the valve body opens, so that external air passes through the two filter membranes to be sampled.

[0022] Furthermore, the valve body includes an inner conical ring fixedly connected to the switching tube, a conical block inserted into the inner conical ring, a ratchet column fixedly connected to the large-diameter end of the conical block, a bracket fixedly connected to the switching tube, the ratchet column slidably connected to the bracket, and a first spring connecting the bracket and the conical block. The filter membrane in the large-diameter direction of the conical block is initially in the working state. When the permeability of the filter membrane in the working state decreases, negative pressure is transmitted to the conical block, causing the conical block to move away from the inner conical ring, thereby opening the valve body and allowing the other filter membrane to enter the working state.

[0023] Furthermore, a threaded cylinder is radially connected through the side wall of the switching tube, a threaded rod is threadedly connected inside the threaded cylinder, a sliding rod is slidably connected inside the threaded rod, a mounting post is fixedly connected to the end of the sliding rod, the mounting post is slidably connected to the threaded cylinder, and a ratchet pawl that mates with the ratchet post is fixedly connected to the end of the mounting post.

[0024] A second spring connects the slide bar and the threaded rod. An indicator light is installed at the end of the threaded rod. A pressure-sensitive switch is installed inside the threaded rod. When the ratchet column slides, it can push the pawl to slide, thereby the second spring applies pressure to the pressure-sensitive switch to make the indicator light light up. The brightness of the indicator light increases with the number of times the pressure-sensitive switch is pressed.

[0025] The beneficial effects of this invention are analyzed as follows:

[0026] An atmospheric sampling module using a membrane filtration method includes a housing. A sampling head base is mounted on the upper part of the housing. The sampling head base has a hole, and a support mesh is fixedly connected inside the hole. The filter membrane is placed on the support mesh. A mass flow meter and a fan are installed inside the housing. An air inlet pipe is installed on the top of the mass flow meter and is connected to the sampling head base. The air inlet of the fan is connected to the mass flow meter. The initial operating voltage of the fan is obtained from the flow indication error of the calibration certificate from the upper module. Based on the built-in voltage-airflow curve obtained from testing the fan, positive and negative voltage feedback is provided for initial flow calibration. The real-time operating voltage of the fan is calibrated by a real-time flow comparison calibration algorithm.

[0027] During atmospheric sampling, a filter membrane is placed on a support net, and a fan is started. The fan's exhaust end is connected to a mass flow meter, and the inlet pipe at the top of the mass flow meter is connected to the fan's exhaust end, with the inlet pipe located at the bottom of the support net. This allows external air to pass through the filter membrane, inlet pipe, and mass flow meter, while atmospheric particles are trapped by the filter membrane. The volume of the sampled atmosphere is set. After sampling, the filter membrane is removed, and its mass is compared with that before use to determine the degree of atmospheric pollution. Before starting the fan, the flow rate indication error from the calibration certificate is input through the upper-level module. Based on the voltage-airflow curve during fan operation, the initial operating voltage of the fan is given, thus achieving the first stage of flow rate calibration before sampling. During the sampling process, the flow rate is calibrated using a real-time flow rate comparison calibration algorithm. This involves comparing the actual volume of the sampled atmosphere obtained from the mass flow meter with the ideal volume of the atmosphere sampled by the fan at the current voltage and speed. The system compares the actual volume with the ideal volume and then adjusts the fan's voltage to change its speed, making the actual volume approach the ideal volume, thereby ensuring the accuracy of the sampled volume. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2 This is a schematic diagram of the paperweight ring of the present invention in the open state;

[0030] Figure 3 This is a schematic diagram of the structure of the first ventilation slot of the present invention;

[0031] Figure 4 This is a schematic diagram of the mass flow meter structure of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of the heat dissipation fins of the present invention;

[0033] Figure 6 This is a schematic diagram of the structure of the air intake pipe of the present invention;

[0034] Figure 7 This is a schematic diagram of the structure at the exhaust port of the present invention;

[0035] Figure 8 This is a schematic diagram of the structure of the switching tube in this invention;

[0036] Figure 9 For the present invention Figure 8 A schematic diagram of the structure of part A;

[0037] Figure 10 This is a schematic diagram of the structure of the pawl in this invention.

[0038] In the diagram: 100, housing; 110, heat dissipation opening; 120, first ventilation slot; 130, second ventilation slot; 140, internal frame; 200, sampling head base; 210, paperweight ring; 220, support mesh; 300, mass flow meter; 310, fan; 340, silencer box; 341, heat dissipation fins; 342, controller circuit; 343, magnetic signal and power interface; 345, exhaust port; 346, cooling fan; 350, air duct; 360, air inlet pipe; 400, switching pipe; 410, inner cone ring; 420, cone block; 430, bracket; 440, ratchet post; 450, first spring; 460, threaded cylinder; 470, mounting post; 471, slide bar; 472, second spring; 480, pawl; 490, threaded rod; 491, indicator light. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Examples, such as Figures 1-10 As shown, an atmospheric sampling module using a membrane filtration method includes a housing 100. A sampling head base 200 is mounted on the upper part of the housing 100. The sampling head base 200 has a hole, and a support net 220 is fixedly connected inside the hole. The filter membrane is placed on the support net 220. A mass flow meter 300 and a fan 310 are installed inside the housing 100. An air inlet pipe 360 ​​is mounted on the top of the mass flow meter 300 and is connected to the sampling head base 200. The air inlet of the fan 310 is connected to the mass flow meter 300. The initial operating voltage of the fan 310 is obtained from the flow indication error of the calibration certificate obtained by the upper module. The upper module provides positive and negative voltage feedback based on the built-in voltage-airflow curve obtained from testing the fan 310 to perform initial flow calibration. The real-time operating voltage of the fan 310 is calibrated by a real-time flow comparison calibration algorithm.

[0041] The working mechanism of the air sampling module using the membrane filtration method provided in this embodiment is as follows:

[0042] When sampling the atmosphere, place the filter membrane on the support net 220 and start the fan 310. The air extraction end of the fan 310 is connected to the mass flow meter 300, and the air intake pipe 360 at the top of the mass flow meter 300 communicates with the air extraction end of the fan 310, and the air intake pipe 360 is located at the lower part of the support net 220, so that external air can pass through the filter membrane, the air intake pipe 360 and the mass flow meter 300, and particles in the atmosphere are retained by the filter membrane. After setting the volume of the atmosphere to be sampled and completing the sampling, the filter membrane is removed, and the mass of the filter membrane before use is compared, so as to obtain the pollution degree of the atmosphere;

[0043] Before the fan 310 is started, the flow indication error of the verification certificate is input through the upper module, and then the initial operating voltage of the fan 310 is given according to the voltage-air volume curve of the fan 310 during operation, so as to realize the first-stage flow calibration before sampling;

[0044] During the sampling process, the flow is calibrated by a real-time flow comparison calibration algorithm, that is, comparing the actual volume of collected atmosphere obtained by the mass flow meter 300 with the ideal volume of atmosphere collected by the fan 310 at the current voltage and rotation speed at the current moment. The system compares the actual volume with the ideal volume, and then changes the rotation speed of the fan 310 by adjusting the voltage of the fan 310, so that the actual volume approaches the ideal volume, thereby ensuring the accuracy of the sampling volume.

[0045] In an optional mode of this embodiment, it is more preferable that:

[0046] The real-time flow comparison calibration algorithm comprises: obtaining a theoretical flow volume of Z liters according to the formula X*Y=Z; wherein X represents the set flow, in LPM, and Y represents the operation duration, in min; obtaining the actual volume measured by the mass flow meter 300 as A liters; judging the magnitude relationship between A and Z: when A>Z, reduce the voltage of the fan 310; when A<Z, increase the voltage of the fan 310; when A=Z, maintain the voltage of the fan 310.

[0047] When adopting the real-time flow comparison calibration algorithm, first set an operation duration Y, obtain the air volume under the current voltage according to the voltage-air volume curve of the fan 310, so as to obtain the ideal flow X, obtain the ideal volume Z liters according to X*Y=Z, then compare Z with the actual volume A liters measured by the mass flow meter 300, and adjust the voltage of the fan 310 according to the magnitude relationship between A and Z, so that the rotation speed of the fan 310 changes and the flow changes, thereby ensuring that A and Z tend to be close and guarantee the sampling accuracy.

[0048] In an optional mode of this embodiment, it is more preferable that:

[0049] The atmospheric sampling volume is set to Z. When the atmospheric sampling volume approaches Z, the operation of the fan 310 is controlled by a wake control algorithm to reduce the wake. The wake control algorithm includes setting the volume of the wake time period to be (ZZ / T)L, where T represents the sampling duration; when the sampling volume reaches (ZZ / T)L but has not reached one-tenth of the final total sampling volume Z, the voltage of the fan 310 is gradually reduced; and when the final total sampling volume Z is reached, the power supply of the fan 310 is cut off, and the fan 310 is started and stopped by pulse power supply until the final sampling volume approaches the set volume Z.

[0050] Set the total volume Z of the atmospheric sample to be sampled. When the sampled atmospheric volume is close to Z, control the speed of the fan 310 through the wake control algorithm to reduce the wake and ensure the accuracy of sampling.

[0051] The sampling duration T is set. When the sampled volume reaches (ZZ / T)L, it indicates that the sampling has reached the wake stage. At this time, the voltage of the fan 310 is gradually reduced, with the voltage reduction value being equal each time, so that the speed of the fan 310 gradually decreases. When the sampled volume reaches one-tenth of the total volume Z, the system cuts off the power supply to the fan 310. Then, the fan 310 is powered by pulse power supply, so that the motor 310 starts and stops the fan in a very short time to obtain a short-term small volume air sample, so that the final sampled volume is as close as possible to the set volume.

[0052] Among the optional methods in this embodiment, the more preferred one is:

[0053] The housing 100 includes an inner frame 140, with eight panels mounted on the outside of the inner frame 140. A sampling head base 200 is mounted on the upper panel, and a paperweight ring 210 is hinged to the sampling head base 200. The paperweight ring 210 can swing and is magnetically attracted to the sampling head base 200.

[0054] During module installation, the sampling head base 200 is first installed on the upper panel of the housing 100. The sampling head base 200 is hinged to the paperweight ring 210. Magnets are installed on the paperweight ring 210 and the sampling head base 200 to allow the paperweight ring 210 to be magnetically attracted to the sampling head base 200.

[0055] Among the optional methods in this embodiment, the more preferred one is:

[0056] A silencer box 340 is fixedly connected inside the housing 100. The air outlet of the fan 310 is connected to the silencer box 340 through the air duct 350. An exhaust port 345 is provided at the bottom of the silencer box 340. A second ventilation slot 130 that cooperates with the exhaust port 345 is provided on the bottom panel of the housing 100.

[0057] The air outlet of the fan 310 is connected to the silencer box 340, which reduces the noise during operation of the device. The air is discharged through the exhaust port 345 at the bottom of the silencer box 340 and the second ventilation slot 130 on the bottom panel of the box 100. The bottom panel of the box 100 is also provided with a first ventilation slot 120 that cooperates with the fan 310.

[0058] Among the optional methods in this embodiment, the more preferred one is:

[0059] A heat dissipation fin 341 is fixedly connected inside the housing 100. A controller circuit 342 is connected to the heat dissipation fin 341. The controller circuit 342 is connected to a magnetic signal and power interface 343.

[0060] The heat sink 341 provides heat dissipation for the controller circuit 342. The controller circuit 342 is mounted on the heat sink 341 by screws or the like. The fan 310 and the mass flow meter 300 are connected to the controller circuit 342.

[0061] Among the optional methods in this embodiment, the more preferred one is:

[0062] A cooling fan 346 is installed inside the enclosure 100. The cooling fan 346 is located on the upper part of the heat dissipation fins 341. The upper panel of the enclosure 100 has a heat dissipation opening 110 that cooperates with the cooling fan 346.

[0063] The cooling fan 346 assists in cooling the heat sink 341, and the heat is exhausted through the heat dissipation opening 110 on the upper panel of the case 100.

[0064] The exhaust gas temperature was reduced by installing a cooling fan 346, heat dissipation fins 341, and a muffler box 340.

[0065] Among the optional methods in this embodiment, the more preferred one is:

[0066] Two support nets 220 are installed on the sampling head base 200. Filter membranes are placed on both support nets 220. There are two air inlet pipes 360, which are respectively set at the lower part of the two support nets 220. A switching pipe 400 is connected between the two air inlet pipes 360. A valve body is set in the switching pipe 400. When the permeability of the filter membrane on one of the support nets 220 decreases, the valve body opens, so that external air passes through the two filter membranes to be sampled.

[0067] The support net 220, filter membrane, and air inlet pipe 360 ​​are all provided in two. In the initial state, only one filter membrane is in working condition. If the sampling volume is large or the air pollution is severe, the permeability of one filter membrane will decrease, thereby opening the valve body in the switching pipe 400, so that the other filter membrane will also be in working condition. At this time, both filter membranes will be working, thereby ensuring that the sampling time is shortened and the sampling efficiency is guaranteed.

[0068] Among the optional methods in this embodiment, the more preferred one is:

[0069] The valve body includes an inner conical ring 410 fixedly connected to a switching tube 400, a conical block 420 inserted into the inner conical ring 410, a ratchet column 440 fixedly connected to the large-diameter end of the conical block 420, a bracket 430 fixedly connected to the switching tube 400, the ratchet column 440 slidably connected to the bracket 430, and a first spring 450 connected between the bracket 430 and the conical block 420. The filter membrane in the large-diameter direction of the conical block 420 is initially in the working state. When the permeability of the filter membrane in the working state decreases, negative pressure is transmitted to the conical block 420, causing the conical block 420 to move away from the inner conical ring 410, thereby opening the valve body and allowing another filter membrane to enter the working state.

[0070] When the permeability of one of the filter membranes decreases, the negative pressure in the switching tube 400 increases, thereby driving the cone block 420 to move away from the inner cone ring 410. At this time, a gap is generated between the inner cone ring 410 and the cone block 420, thereby transmitting the negative pressure to the other air intake pipe 360, so that the filter membrane on the upper part of the other air intake pipe 360 ​​is in working condition.

[0071] Among the optional methods in this embodiment, the more preferred one is:

[0072] A threaded cylinder 460 is radially connected through the side wall of the switching tube 400. A threaded rod 490 is threadedly connected inside the threaded cylinder 460. A slide rod 471 is slidably connected inside the threaded rod 490. A mounting post 470 is fixedly connected to the end of the slide rod 471. The mounting post 470 is slidably connected to the threaded cylinder 460, and a pawl 480 that mates with a ratchet post 440 is fixedly connected to the end of the mounting post 470. A second spring 472 is connected between the slide rod 471 and the threaded rod 490. An indicator light 491 is installed at the end of the threaded rod 490. A pressure-sensitive switch is provided inside the threaded rod 490. When the ratchet post 440 slides, it can push the pawl 480 to slide, thereby the second spring 472 applies pressure to the pressure-sensitive switch to make the indicator light 491 light up. The brightness of the indicator light 491 increases with the number of times the pressure-sensitive switch is pressed.

[0073] The threaded cylinder 460 is fixedly connected to the switching pipe 400. The threaded rod 490 is screwed into the threaded cylinder 460. A nut is provided at the end of the threaded rod 490. A sealing ring is provided between the nut and the port of the threaded cylinder 460 to ensure sealing. When screwing in, first align the keyway on the mounting post 470 with the key in the threaded cylinder 460, and then tighten the threaded rod 490. At this time, the pawl 480 on the mounting post 470 is engaged in the tooth gap on the ratchet post 440. When the negative pressure causes the cone block 420 to move away from the inner cone ring 410, the ratchet post 440 slides relative to the bracket 430, and the first spring 450 is compressed. At this time, the ratchet post 440 can slide relative to the pawl 480. 80 slides, then the pawl 480 limits the ratchet post 440, maintaining the gap between the inner cone ring 410 and the cone block 420. If the negative pressure in the switching tube 400 continues to increase, the cone block 420 continues to slide. At this time, the ratchet post 440 continues to slide relative to the pawl 480. When the ratchet post 440 slides multiple times, the pawl 480 will be pushed multiple times, so the second spring 472 will be compressed multiple times and squeeze the pressure-sensitive switch multiple times. At this time, the brightness of the indicator light 491 increases. Finally, when measuring the change in filter membrane quality or the condition of the deposits, it is determined whether each filter membrane in the chain should be tested based on whether the indicator light 491 is lit.

[0074] Although embodiments of the 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 invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An atmospheric sampling module using a membrane filtration method, comprising a housing (100), characterized in that: A sampling head base (200) is installed on the upper part of said box body (100), a hole is opened on said sampling head base (200), a support net (220) is fixedly connected in the hole, and a filter membrane is placed on said support net (220); A mass flow meter (300) and a fan (310) are installed in said box body (100), an air inlet pipe (360) is installed on the top of said mass flow meter (300), said air inlet pipe (360) is communicated with said sampling head base (200), and the air inlet end of said fan (310) is communicated with said mass flow meter (300); The initial operating voltage of said fan (310) is obtained by an upper module from the flow indication error of the verification certificate, and flow calibration for initial operation is performed through positive and negative voltage feedback based on the built-in voltage-air volume curve obtained by testing said fan (310), and The real-time operating voltage of said fan (310) is calibrated by a real-time flow comparison and calibration algorithm; The real-time flow comparison and calibration algorithm includes, according to formula X Y=Z yields the theoretical flow volume as ZL; wherein, X represents the set flow, with a unit of LPM, and Y represents the operating duration, with a unit of min; obtaining the actual volume measured by said mass flow meter (300) as A L; judging the magnitude relationship between A and Z: when A > Z, reducing the voltage of said fan (310); when A < Z, increasing the voltage of said fan (310); when A = Z, maintaining the voltage of said fan (310); setting the atmospheric sampling volume as Z, and when the atmospheric sampling volume approaches Z, controlling the operation of said fan (310) through a wake control algorithm to reduce wake flow, said wake control algorithm comprising: setting the volume reaching the wake time period as (Z-Z / T) L, wherein T represents the sampling duration; when the sampling volume reaches (Z-Z / T) L and does not reach one tenth of the final total sampling volume Z, reducing the voltage of said fan (310) step by step, and when the sampling volume reaches one tenth of the final total sampling volume Z, after cutting off the power supply of said fan (310), starting and stopping the fan (310) through a pulse power supply mode until the final sampling volume approaches the set volume Z.

2. The atmospheric sampling module using membrane filtration according to claim 1, characterized in that: Said box body (100) comprises an inner frame (140), eight panels are installed outside said inner frame (140), said sampling head base (200) is installed on said upper panel, a weight ring (210) is hinged on said sampling head base (200), and said weight ring (210) can swing and is magnetically attracted to said sampling head base (200).

3. The atmospheric sampling module using membrane filtration according to claim 1, characterized in that: A silencing box (340) is fixedly connected in said box body (100), the air outlet end of said fan (310) is communicated with said silencing box (340) through an air duct (350), an exhaust port (345) is opened at the bottom of said silencing box (340), and a second ventilation slot (130) matched with said exhaust port (345) is opened on the bottom panel of said box body (100).

4. The atmospheric sampling module using membrane filtration according to claim 1, characterized in that: A heat dissipation fin (341) is fixedly connected in said box body (100), a controller circuit (342) is connected to said heat dissipation fin (341), and a magnetic attraction type signal and power interface (343) is connected to said controller circuit (342).

5. The atmospheric sampling module using membrane filtration according to claim 4, characterized in that: A cooling fan (346) is installed inside the housing (100). The cooling fan (346) is located on the upper part of the heat dissipation fins (341). The upper panel of the housing (100) has a heat dissipation opening (110) that cooperates with the cooling fan (346).

6. The atmospheric sampling module using membrane filtration according to claim 5, characterized in that: Two support nets (220) are installed on the sampling head base (200). Filter membranes are placed on both support nets (220). There are two air inlet pipes (360). The two air inlet pipes (360) are respectively set at the lower part of the two support nets (220), and a switching pipe (400) is connected between the two air inlet pipes (360). A valve body is provided in the switching pipe (400). When the permeability of the filter membrane on one of the support nets (220) decreases, the valve body opens, so that external air passes through the two filter membranes to be sampled.

7. The atmospheric sampling module using membrane filtration according to claim 6, characterized in that: The valve body includes an inner conical ring (410) fixedly connected to the switching tube (400), a conical block (420) inserted into the inner conical ring (410), a ratchet column (440) fixedly connected to the large diameter end of the conical block (420), a bracket (430) fixedly connected to the switching tube (400), the ratchet column (440) slidably connected to the bracket (430), and a first spring (450) connected between the bracket (430) and the conical block (420). The filter membrane in the large diameter direction of the conical block (420) is initially in the working state. When the permeability of the filter membrane in the working state decreases, negative pressure is transmitted to the conical block (420) so that the conical block (420) moves away from the inner conical ring (410), thereby opening the valve body and allowing another filter membrane to enter the working state.

8. The atmospheric sampling module using membrane filtration according to claim 7, characterized in that: A threaded cylinder (460) is radially connected through the side wall of the switching tube (400). A threaded rod (490) is threadedly connected inside the threaded cylinder (460). A slide rod (471) is slidably connected inside the threaded rod (490). A mounting post (470) is fixedly connected to the end of the slide rod (471). The mounting post (470) is slidably connected to the threaded cylinder (460), and a pawl (480) that mates with the ratchet post (440) is fixedly connected to the end of the mounting post (470). A second spring (472) is connected between the slide bar (471) and the threaded rod (490). An indicator light (491) is installed at the end of the threaded rod (490). A pressure-sensitive switch is provided inside the threaded rod (490). When the ratchet column (440) slides, it can push the pawl (480) to slide, so that the second spring (472) applies pressure to the pressure-sensitive switch to make the indicator light (491) light up. The brightness of the indicator light (491) increases with the number of times the pressure-sensitive switch is pressed.

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