Waste gas indoor filtering device capable of being used for focusing ion beam

Abstract

The invention discloses a waste gas indoor filtering device capable of being used for a focused ion beam, which comprises a silencing unit used for being connected with an exhaust port of a mechanical pump of an electron microscope or a micro-nano machining system; the anti-back-suction filter is connected to the other end of the silencing unit, and one side of the anti-back-suction filter is connected with a waste gas hose; the outer side wall of the filtering, adsorbing and purifying device is provided with an air through quick connector, and the waste gas hose is communicated with the filtering device through the air through quick connector; the dustproof hood is installed at the exhaust end of the filtering, adsorbing and purifying device, exhaust holes are evenly distributed in the dustproof hood, and a powerful exhaust fan is installed in the filtering, adsorbing and purifying device and located on one side of the dustproof hood; the device can be widely applied to scanning electron microscopes, electronic books, ion beam double-beam electron microscopes or micro-nano laser processing systems, PVD (physical vapor deposition), CVD (chemical vapor deposition), glove boxes and other equipment.

Description

Technical Field

[0001] This invention belongs to the field of exhaust gas treatment technology, specifically an indoor filtration device for exhaust gas that can be used with focused ion beams. Background Technology

[0002] Both the dual-beam electron microscope and the micro / nano laser processing system are equipped with a dedicated auxiliary gas injection system, which can perform additive manufacturing at the micron scale or deposit composite metal films or insulator films with a thickness of 50 nanometers to 2 micrometers. They can also perform circuit repair and transmission electron microscope sample preparation. The exhaust gases generated by dual-beam electron microscopes and micro / nano laser processing systems are generally required to be directly discharged outdoors or into dedicated pollution gas treatment pipelines. However, in actual use, the necessary space and accessories are often lacking, resulting in direct indoor emissions of pollutants, causing indoor heavy metal and toxic chemical gas pollution. Traditional exhaust gas filtration and treatment devices are costly to scale up and integrate, and have high requirements for the basic conditions for exhaust gas discharge. Furthermore, dual-beam electron microscopes cannot economically and effectively treat exhaust gases, leading to heavy metal pollution, noise pollution, and toxic chemical pollution.

[0003] Therefore, it is necessary to provide an exhaust gas chamber filtration device that can be used for focused ion beams to solve the problems mentioned in the background art. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides the following technical solution: an indoor filtration device for exhaust gas that can be used with focused ion beams, comprising: A noise reduction unit is used to connect to the exhaust port of a mechanical pump in an electron microscope or micro / nano fabrication system. An anti-backflow filter is connected to the other end of the silencer unit, and an exhaust hose is connected to one side of the anti-backflow filter; The filtration and adsorption purification device has an air inlet on its outer wall, and the exhaust gas hose is connected to the filtration device through the air inlet. A dust cover is installed at the exhaust end of the filter adsorption purification device. The dust cover has evenly distributed exhaust holes. A powerful exhaust fan is installed inside the filter adsorption purification device on one side of the dust cover.

[0005] Furthermore, preferably, the noise reduction unit includes: A silicone tube, one end of which is sealed and fitted onto the inlet end of the anti-backflow filter; A noise-absorbing ring is sealed to the other end of a silicone tube, and the end of the silicone tube is fitted with a noise-absorbing flange on the outer sleeve of the noise-absorbing ring.

[0006] Furthermore, as a preferred embodiment, the silencing ring is provided with silencing holes, which have a gradually decreasing diameter structure, and the diameter of the hole on the side closer to the silicone tube is smaller than the diameter of the hole on the other side.

[0007] Furthermore, preferably, the filtration and adsorption purification device includes: The housing has a medium-efficiency filter layer installed inside, on the side near the air inlet. The first deacid chemical filter layer and the second deacid chemical filter layer are arranged in parallel inside the housing and located on one side of the medium-efficiency filter layer. The activated carbon filtration unit is located between the first acid-removing chemical filtration layer and the medium-efficiency filtration layer.

[0008] Furthermore, preferably, the activated carbon filtration unit includes: Framework; The activated carbon layers are arranged in multiple ways, and each activated carbon layer is tightly installed in the frame body; The guide rods are arranged symmetrically in two places. Two positioning plates are arranged in parallel within the frame. The two ends of the guide rods are fixed to the positioning plates respectively. Air guide plates are provided corresponding to each of the activated carbon layers. Each air guide plate is assembled and fixed on two guide rods, and each air guide plate is in sealed contact with the periphery of each activated carbon layer.

[0009] Furthermore, as a preferred embodiment, the activated carbon layer is provided with a central layer and an outer layer, which are separated by a ring. The ring is provided with a plurality of one-way air holes around its circumference so that the exhaust gas entering the central layer can enter the outer layer through the one-way air holes. Each activated carbon layer has a sealing plate fixed on one side. The sealing plate has multiple side through holes around its circumference. A sealing disc is rotatably connected to the sealing plate. The sealing disc has multiple guide holes corresponding to the side through holes.

[0010] Furthermore, as a preferred embodiment, two rubber ring layers are symmetrically arranged on the inner sidewall of the air guide plate, and a connecting cavity is opened in the air guide plate. The connecting cavity has a U-shaped structure, and multiple suction holes are evenly distributed on the connecting cavity. The conductive cavity also has several exhaust holes distributed on it.

[0011] Furthermore, as a preferred embodiment, the vent holes and suction holes are arranged at intervals, and the number of suction holes is twice the total number of vent holes.

[0012] Furthermore, as a preferred embodiment, a reciprocating pump is provided outside the frame body, and multiple diversion pipes are externally connected to the reciprocating pump. The other end of each diversion pipe is connected to a corresponding air guide plate, and a valve is provided on each diversion pipe. A section tube is fixed at one end of the diversion pipe near the air guide plate. A bypass channel is opened on the side wall of the section tube. The bypass channel is sealed and connected to the guide cavity. A central tube is provided inside the section tube. A one-way tube is vertically inserted into the activated carbon layer. The central tube is connected to the one-way tube, and the other end of the one-way tube is connected to the ring sleeve.

[0013] Furthermore, as a preferred embodiment, both the central layer and the outer layer are made of honeycomb core material, and the honeycomb pores of each honeycomb core material are filled with activated carbon.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention can effectively treat industrial waste gases generated by focused ion beam dual-beam electron microscopes, scanning electron microscopes, micro-nano laser processing systems, glove boxes, etc. The device can effectively treat various waste gas pollutants from electron beams, ion beams, lasers, or chemical reactions in electron microscopes or micro-nano processing systems through physical adsorption filtration and chemical deacidification filtration. It adsorbs and treats heavy metals and oxide particles, and chemically deacidifies and filters toxic and corrosive gases, ensuring the normal operation of the instrument and the health of the personnel. Its internal powerful exhaust fan promotes the adsorption of exhaust gases and their contact with chemical substances for decomposition, while reducing the pumping load of the electron microscope's mechanical pump, facilitating long-term stable operation. The entire device is miniaturized and integrated, allowing for direct indoor use. The filtration and adsorption purification device in this invention uses multiple activated carbon layers arranged in combination. Each activated carbon layer is divided into three stages according to its function: a first stage, a second stage, and a third stage, which are respectively a pre-protection layer, a main adsorption layer, and a fine treatment layer. Compared with the traditional single-layer activated carbon plate design, this invention can use different levels of activated carbon layers according to the characteristics of pollutants, thereby improving the filtration and adsorption effect. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure of the noise reduction unit in this invention; Figure 3 This is a schematic diagram of the structure of the noise-absorbing ring in this invention; Figure 4 This is a schematic diagram of the filtration and adsorption purification device in this invention; Figure 5 This is a schematic diagram of the activated carbon filtration unit in this invention; Figure 6 This is a cross-sectional view of the air guide plate in this invention; Figure 7 This is a schematic diagram of the conductive cavity in this invention; Figure 8 This is a schematic diagram of the activated carbon layer in this invention; Figure 9This is a schematic diagram of the structure of the central layer in this invention; Figure 10 This is a schematic diagram of the flow path of waste gas through each activated carbon layer in this invention; In the diagram: 1. Silica gel unit; 11. Silicone tubing; 12. Silica gel ring; 13. Silica gel flange; 14. Silica gel hole; 15. Sealing ring; 2. Anti-backflow filter; 21. Exhaust gas hose; 3. Filtration adsorption purification device; 31. Powerful exhaust fan; 32. Dustproof cover; 33. Housing; 34. Medium-efficiency filter layer; 35. First acid removal chemical filter layer; 36. Second acid removal chemical filter layer; 4. Activated carbon filter unit; 41. 42. Frame; 43. Guide rod; 44. Positioning plate; 45. Reciprocating pump; 46. Diverter pipe; 47. Valve; 48. Joint pipe; 49. Central pipe; 50. One-way pipe; 51. Activated carbon layer; 52. Central layer; 53. Outer layer; 54. Ring sleeve; 55. Seal plate; 56. Side through hole; 57. Sealing plate; 68. Guide hole; 69. Air guide plate; 60. Rubber ring layer; 61. Conducting cavity; 62. Suction hole; 63. Exhaust hole. Detailed Implementation

[0016] Please see Figures 1-10 In this embodiment of the invention, an indoor filtration device for exhaust gas that can be used with focused ion beams includes: Silencing unit 1 is used to connect to the exhaust port of the mechanical pump of the electron microscope or micro / nano fabrication system; Anti-backflow filter 2 is connected to the other end of the silencer unit 1. One side of the anti-backflow filter 2 is connected to the exhaust gas hose 21. The anti-backflow filter 2 is mainly used to prevent special backflow situations of the vacuum pump, such as sudden power failure. Such situations will cause the vacuum pump to suck in solid contaminants, causing internal wear of the vacuum pump, leading to failure and reducing its service life. The filter adsorption purification device 3 has an air quick-connect interface on its outer wall, and the exhaust gas hose 21 is connected to the filter device 3 through the air quick-connect interface. A dust cover 32 is installed at the exhaust end of the filter adsorption purification device 3. The dust cover 32 has evenly distributed exhaust holes. A powerful exhaust fan 31 is installed inside the filter adsorption purification device 3 on one side of the dust cover 32. The powerful exhaust fan 31 can promote the adsorption of exhaust gas and the contact decomposition of chemical substances, and at the same time reduce the air pumping load of the electron microscope mechanical pump, which is conducive to the long-term stable operation of the machine. The filter adsorption purification device 3 in this device can effectively treat the exhaust gas generated by the dual-beam electron microscope and filter the exhaust gas to meet the requirements of harmless treatment. The device has a small overall size and occupies little space, so it can be used directly indoors.

[0017] In this embodiment, the noise reduction unit 1 includes: The silicone tube 11 has one end sealed and fitted to the inlet end of the anti-backflow filter 2. It has good flexibility and high vibration isolation effect, reducing the transmission of low-frequency vibration to the exhaust gas treatment pipeline. The noise-absorbing ring 12 is sealed and assembled at the other end of the silicone tube 11. The end of the silicone tube 11 is located on the outer sleeve of the noise-absorbing ring 12 and a noise-absorbing flange 13 is provided. The noise-absorbing ring 12 and the noise-absorbing flange 13 can be in close contact through a sealing rubber ring 15. The noise-absorbing ring 12 is connected to a special silent airtight flange of the mechanical pump of the electron microscope or micro-nano processing system. One end of the ring 12 can be placed in the airtight flange connected to the exhaust port of the mechanical pump near the electron microscope.

[0018] In a preferred embodiment, the silencing ring 12 is provided with silencing holes 14, which are three in a centrally symmetrical arrangement. The silencing holes 14 have a gradually changing diameter structure, and the diameter of the hole on the side closer to the silicone tube 11 is smaller than that on the other side. This can effectively reduce the airflow noise and vibration generated when the mechanical pump exhausts.

[0019] In this embodiment, the filtration and adsorption purification device 3 includes: The housing 33 has a medium-efficiency filter layer 34 installed inside it on the side near the air inlet. The first deacid chemical filter layer 35 and the second deacid chemical filter layer 36 are arranged in parallel inside the housing 33 and located on one side of the medium-efficiency filter layer 34. Both the first deacid chemical filter layer 35 and the second deacid chemical filter layer 36 adopt a sandwich structure. The filter element uses porous alumina balls and molecular sieves to load the chemical filter material. The load material can be replaced and adjusted according to actual needs, and the load material can be mixed and proportioned to facilitate optimization according to different usage scenarios. The activated carbon filter unit 4 is disposed between the first deacidification chemical filter layer 35 and the medium-efficiency filter layer 34. The activated carbon filter unit 4 can work with the medium-efficiency filter layer 34 to form a double-layer physical filtration.

[0020] In this embodiment, the activated carbon filtration unit 4 includes: Frame 41; The activated carbon layer 5 consists of multiple layers arranged in a row. Each activated carbon layer 5 is tightly installed inside the frame body 41. In this way, the multiple activated carbon layers 5 are combined to form the waste gas flow path through the filter. The guide rods 42 are two symmetrically arranged. Two positioning plates 43 are arranged in parallel inside the frame body 41. The two ends of the guide rods 42 are fixed to the positioning plates 43 respectively. The air guide plate 6 is provided corresponding to each of the activated carbon layers 5. The air guide plate 6 is assembled and fixed on two guide rods. Each air guide plate 6 is in sealed contact with the periphery of each activated carbon layer 5. In this way, multiple air guide plates 6 can form an outer wrap around the activated carbon layer 5, with a good sealing effect and no exhaust gas leakage. Furthermore, the activated carbon layers 5 in this device are divided into three stages according to their functions: the first stage, the second stage, and the third stage, which are respectively the pre-protection layer, the main adsorption layer, and the fine treatment layer. The pre-protective layer mainly adsorbs large molecules, high-boiling-point pollutants, and easily polymerized pollutants, as well as removes moisture and some dust. Its activated carbon is low-cost coal-based granular carbon or honeycomb carbon with well-developed mesopores and macropores. The main adsorption layer mainly adsorbs the most concentrated and important VOCs components in the waste gas. Its activated carbon is made of high-quality coconut shell carbon or coal-based carbon with extremely well-developed micropores to ensure the maximum adsorption capacity for the target substances. The fine treatment layer mainly removes trace and specific pollutants that were not completely adsorbed in the first two stages, ensuring that emissions meet standards. The activated carbon used in this layer is a special activated carbon that has undergone surface chemical modification. For example, if the exhaust gas contains trace amounts of hydrogen sulfide, the activated carbon in the fine treatment layer is alkaline activated carbon impregnated with NaOH; if it contains trace amounts of ammonia, acidic activated carbon impregnated with phosphoric acid or sulfuric acid is used.

[0021] In this embodiment, the activated carbon layer 5 is provided with a central layer 51 and an outer layer 52. The central layer 51 and the outer layer 52 are separated by a ring 53. The ring 53 has multiple one-way air holes around its circumference so that the exhaust gas entering the central layer 51 can enter the outer layer 52 through the one-way air holes. The rings 53 in adjacent activated carbon layers 5 can be combined and assembled so that the rings 53 in multiple activated carbon layers 5 can form a tubular channel. The exhaust gas flows in a straight line through the tubular channel and passes through each activated carbon layer 5 in sequence. Each activated carbon layer 5 has a sealing plate 54 fixed on one side. The sealing plate 54 has multiple side through holes 55 circumferentially formed. A sealing disk 56 is rotatably connected to the sealing plate 54. The sealing disk 56 has multiple guide holes 57 corresponding to the side through holes 55. When the guide holes 57 are staggered from the side through holes 55 on the sealing plate 54, the outer layers 52 of each activated carbon layer 5 are independently separated. After the exhaust gas enters the outer layers 52 through the central layer 51, it will not flow into the adjacent activated carbon layer 5. Therefore, in use, on the one hand, activated carbon layers 5 of the same level can be grouped according to the functional level of each activated carbon layer 5. On the other hand, activated carbon layers 5 of the same level can be further divided to optimize the exhaust gas filtration strategy.

[0022] In a preferred embodiment, two rubber ring layers 61 are symmetrically arranged on the inner sidewall of the air guide plate 6, and a through cavity 62 is opened in the air guide plate 6. The through cavity 62 has a U-shaped structure, and a plurality of suction holes 63 are evenly distributed on the through cavity 62. The conductive cavity 62 is also provided with several exhaust holes 64. With this configuration, the conductive cavity 62 can form a negative pressure suction in the outer layer 52 of the activated carbon layer 5 through the suction hole 63. When the exhaust gas passes through the activated carbon layer 5, it flows through the central layer 51 and enters the outer layer 52 through the one-way air hole of the ring 53. When the conductive cavity 62 exhausts under high pressure, the exhaust gas that has entered the conductive cavity 62 can re-enter the outer layer 52 through the exhaust hole 64. This cycle repeats, enhancing the air passage effect and improving the exhaust gas adsorption and filtration intensity.

[0023] In this embodiment, the exhaust holes 64 and suction holes 63 are arranged at intervals, or they can be arranged separately in the horizontal and vertical directions to enhance the complexity of the exhaust gas flow path, thereby improving the filtration and adsorption effect. The number of suction holes 63 is twice the total number of exhaust holes 64.

[0024] In this embodiment, a reciprocating pump 44 is provided outside the frame 41. The reciprocating pump 44 can perform reciprocating circulation for air extraction and exhaust. Multiple diversion pipes 45 are connected to the outside of the reciprocating pump 44. The other end of each diversion pipe 45 is connected to the air guide plate 6. Each diversion pipe 45 is provided with a valve 46 to control the opening or closing of the diversion pipe 45. In order to avoid the waste gas in each diversion pipe 45 from mixing in the reciprocating pump 44 and affecting the waste gas treatment effect, the reciprocating pump 44 adopts a multi-cylinder (multi-chamber) structure, with each independent cylinder connected to an independent diversion pipe. A segmented pipe 47 is fixed to one end of the diversion pipe 45 near the gas guide plate 6. A bypass channel is opened on the side wall of the segmented pipe 47, which is sealed and connected to the guiding cavity 62. A central pipe 48 is provided inside the segmented pipe 47. A one-way pipe 49 is vertically inserted into the activated carbon layer 5 so that the gas in the central pipe 48 can enter the one-way pipe 49 in one direction without backflow. The central pipe 48 is connected to the one-way pipe 49, and the other end of the one-way pipe 49 is connected to the ring 53. In this device, since the number of suction holes 63 is set to twice the total number of exhaust holes 64, the reciprocating pump 44 works continuously and reciprocates to draw and exhaust gas during use. When it draws gas, the exhaust gas enters the guiding cavity through multiple suction holes 63. 62, while a portion of the exhaust gas enters the junction pipe 47 through the bypass channel; when the reciprocating pump 44 exhausts, a portion of the exhaust gas directly enters the central layer 51 through the one-way pipe 49, while the other portion of the exhaust gas re-enters the outer layer 52 through each exhaust port 64; therefore, according to the characteristics of the exhaust gas pollution concentration, the valve 46 on the corresponding diversion pipe 45 can be opened accordingly, so that the exhaust gas flowing through the corresponding activated carbon layer 5 can flow from the central layer 51 into the outer layer 52, and after being efficiently circulated and discharged by the outer layer 52, it re-enters the central layer 51, and then is discharged along the tubular channel, which enhances the exhaust gas treatment effect. Moreover, the central layer 51 of the activated carbon layer 5, which is set in this way, will not be saturated with adsorption in the short term due to long-term use, thus extending the service life.

[0025] Both the central layer 51 and the outer layer 52 are made of honeycomb core material, and the honeycomb pores of each honeycomb core material are filled with activated carbon. The use of honeycomb core material can facilitate the flow of waste gas through the honeycomb pores of the honeycomb core material, so that after passing through the activated carbon layer 5, the waste gas diffuses along its spread surface, thereby improving the filtration and adsorption effect.

[0026] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A filter device for use in a waste gas chamber of a focused ion beam, characterized in that It includes: Silencer unit (1) for connecting the exhaust port of mechanical pump of electric mirror or micro-nano processing system; Anti-suction filter (2) connected at the other end of the silencer unit (1), one side of the anti-suction filter (2) is connected with exhaust hose (21); Filtering and adsorbing purification device (3) is provided with gas through quick connector on the outer wall, the exhaust hose (21) is connected with the filtering device (3) through the gas through quick connector; Dustproof cover (32) is installed at the exhaust end of the filtering and adsorbing purification device (3), the dustproof cover (32) is uniformly distributed with exhaust holes, the filtering and adsorbing purification device (3) is installed with powerful exhaust fan (31) on one side of the dustproof cover (32).

2. A filter device for use in a waste gas chamber of a focused ion beam according to claim 1, characterized in that The silencer unit (1) comprises: Silica gel pipe (11) is sealed and sleeved at the inlet end of the anti-suction filter (2); Silencer ring (12) is sealingly assembled at the other end of the silica gel pipe (11), and the end of the silica gel pipe (11) is sleeved with a silencer flange (13) outside the silencer ring (12).

3. The filter device for use in a waste gas chamber of a focused ion beam according to claim 1, characterized in that: The silencer ring (12) is provided with a silencer hole (14), the silencer hole (14) is a gradually changing diameter structure, and the hole diameter near the silica gel pipe (11) is smaller than the hole diameter on the other side.

4. The filter device for use in a waste gas chamber of a focused ion beam according to claim 1, characterized in that The filtering and adsorbing purification device (3) comprises: Casing (33) is installed with medium efficiency filter layer (34) on one side near the gas through quick connector inside; First acid-removing chemical filter layer (35) and second acid-removing chemical filter layer (36) are arranged in parallel in the casing (33) and located on one side of the medium efficiency filter layer (34); Activated carbon filter unit (4) is arranged between the first acid-removing chemical filter layer (35) and the medium efficiency filter layer (34).

5. A filter device for use in a waste gas chamber of a focused ion beam according to claim 4, characterized in that The activated carbon filter unit (4) comprises: Frame body (41); Activated carbon layer (5) is arranged in multiple, each activated carbon layer (5) is tightly installed in the frame body (41); Guide rod (42) is symmetrically arranged in two, two positioning plates (43) are arranged in parallel in the frame body (41), and the two ends of the guide rod (42) are respectively fixed with the positioning plates (43); Air guide plate (6) is arranged corresponding to each activated carbon layer (5), and the air guide plate (6) is assembled and fixed on the two guide rods, and each air guide plate (6) is in sealing contact along the periphery of each activated carbon layer (5).

6. A filter device for use in a waste gas chamber of a focused ion beam according to claim 5, characterized in that: The activated carbon layer (5) is provided with a center layer (51) and a peripheral layer (52), the center layer (51) and the peripheral layer (52) are separated by a ring (53), a plurality of one-way air holes are circumferentially arranged on the ring (53), so that the exhaust gas entering the center layer (51) enters the peripheral layer (52) through the one-way air holes; Each activated carbon layer (5) is fixed with a partition plate (54) on one side, a plurality of side through holes (55) are circumferentially arranged on the partition plate (54), and a sealing disc (56) is rotatably connected to the partition plate (54), a plurality of guide holes (57) corresponding to the side through holes (55) are arranged on the sealing disc (56).

7. A filter device for use in a waste gas chamber of a focused ion beam according to claim 5, characterized in that: The inner side wall of the air guide plate (6) is symmetrically provided with two rubber ring layers (61), and a through cavity (62) is formed in the air guide plate (6), wherein the through cavity (62) is in a back-shaped structure, and a plurality of suction holes (63) are equidistantly distributed on the through cavity (62). A plurality of exhaust holes (64) are also distributed on the through cavity (62).

8. A filter device for use in a waste gas chamber of a focused ion beam according to claim 7, characterized in that: The exhaust holes (64) and the suction holes (63) are arranged in an interval distribution mode, the number of the suction holes (63) is twice the total number of the exhaust holes (64).

9. A filter device for use in a waste gas chamber of a focused ion beam according to claim 8, characterized in that: A reciprocating pump (44) is arranged outside the frame body (41), a plurality of shunt pipes (45) are connected to the reciprocating pump (44), one end of each shunt pipe (45) is in communication with the air guide plate (6), and a valve (46) is arranged on each shunt pipe (45). One end of the shunt pipe (45) close to the air guide plate (6) is fixedly connected with a joint pipe (47), a bypass channel is formed in the side wall of the joint pipe (47), the bypass channel is in sealed communication with the through cavity (62), a center pipe (48) is arranged in the joint pipe (47), a one-way pipe (49) is vertically inserted into the active carbon layer (5), the center pipe (48) is in communication with the one-way pipe (49), and the other end of the one-way pipe (49) is connected with a ring sleeve (53).

10. The filter device for use in a waste gas chamber of a focused ion beam according to claim 6, characterized in that: The center layer (51) and the peripheral layer (52) are both made of honeycomb core materials, and the honeycomb holes of each honeycomb core material are filled with active carbon.

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