Fan filter units and fresh air systems

Abstract

The application relates to the technical field of air purification equipment, and discloses a fan filter, a filter unit and a dust-free site, wherein the fan filter comprises a shell, a fan and a filter plate, the filter plate is detachably connected to the shell, a shielding assembly is arranged at an air inlet of the dust-free site and is suitable for closing and opening the air inlet, and a hinged piece is connected with the shell and is suitable for driving one side of the shell provided with the filter plate to be close to or far away from the air inlet. The application solves the problem that when the filter plate of the fan filter group is replaced, the equipment in the dust-free site needs to be stopped for treatment, thereby affecting the production efficiency.

Description

Technical Field

[0001] This invention relates to the field of air purification equipment technology, specifically to a fan filter, a filter unit, and a fresh air system. Background Technology

[0002] An FFU (Fan Filter Unit) is a fan-assisted air handling unit widely used in cleanrooms, dust-free rooms, and other clean environments. Multiple FFUs are typically installed in a cleanroom space to form a fresh air system. These units are connected to the site's ventilation ducts or air inlets. A single FFU generally consists of a casing, a fan, filter elements, and a control system. When the FFU is operating, the fan draws air into the filter. After passing through the filter elements, dust is trapped at the filter element, allowing clean air to enter the clean environment. The filter plates in the filter elements need to be replaced regularly to maintain a stable filtration effect.

[0003] In related technologies, when replacing the filter plates of the filter unit, the equipment in the cleanroom needs to be shut down to avoid the air quality deterioration caused by the failure of air filtration at the air inlet where the filter plate is replaced, which could affect the normal operation of the equipment.

[0004] However, the restart time after some production equipment is down is relatively long. The downtime caused by replacing filter plates seriously affects the production efficiency of the equipment. This is especially true in some large factories where filter plates of multiple fan filter units need to be replaced, resulting in a long overall replacement time and impacting normal production plans. Summary of the Invention

[0005] In view of this, the present invention provides a fan filter, a filter unit, and a fresh air system to solve the problem that when replacing the filter plates of a fan filter unit, it is necessary to shut down the indoor equipment where the fan filter is installed, which affects production efficiency.

[0006] In a first aspect, the present invention provides a fan filter, comprising: a fan; a filter plate; a housing having a cavity, and having an air inlet and an air outlet communicating with the cavity, the fan being disposed within the cavity, and the filter plate being detachably connected to the air outlet of the housing; and a shielding assembly connected to one side of the air outlet of the housing, comprising a shielding plate having a shielding position and an open position, wherein in the shielding position the shielding plate shields the air outlet of the housing, and in the open position the shielding plate is away from the air outlet of the housing.

[0007] Beneficial effects: By setting up a shielding component, the air outlet is sealed when the filter plate is replaced, preventing air from entering the room through the inlet of the filter failure and causing a decline in air quality. It also prevents dust falling from the filter plate during the filter plate replacement process from entering the room. Furthermore, since the sealed structure closes the air inlet at the filter plate replacement point, other fans and filters in the room can continue to operate normally. Therefore, there is no need to shut down the indoor equipment when replacing the filter plate, thereby improving work efficiency.

[0008] In one optional embodiment, the shielding assembly further includes a substrate disposed on one side of the housing, the shielding plate being slidably disposed on the substrate, and guide rails being provided on opposite sides of the substrate for sliding cooperation with the shielding plate.

[0009] Beneficial effects: By setting up a base plate and a baffle plate that slide and cooperate with each other, the structure is simple, inexpensive and easy to operate, allowing the staff to quickly control the opening or closing of the air inlet.

[0010] In one alternative embodiment, the shield is provided with a push-pull handle on the side opposite to the substrate.

[0011] Beneficial effects: By setting push-pull handles, it is easier for staff to push or pull the baffles from inside the room. When the fan filter is set at the top of the cleanroom and the ceiling is high, staff can easily operate the baffles even on scaffolding or ladders.

[0012] In an optional embodiment, a support frame is further included at the blocking position of the baffle plate. The support frame is abutted to and integrally formed with the substrate. The support frame is adapted to abut against the air outlet side of the housing to provide support for the housing. Two opposite slide rails that cooperate with the baffle plate are provided in the support frame. The slide rails correspond one-to-one with the guide rails and are connected.

[0013] Beneficial effects: By setting a support frame at the air inlet, when the fan filter group is working normally, the outer casing is located on the upper side of the support frame and abuts against the support frame. The support frame provides a support base and limit for the outer casing, and provides support for the baffle when the baffle moves to the baffle position.

[0014] In one alternative embodiment, the housing is hinged to the substrate via a hinge, and the housing has a working position and a flip position. In the working position, the air outlet side of the housing abuts against the support frame. In the flip position, the housing is located on the upper side of the substrate, and the sidewall of the housing abuts against the upper sidewall of the substrate.

[0015] Beneficial effects: By incorporating a hinge, the side of the housing containing the filter plate can be moved away from the air inlet, providing ample operating space for personnel to replace the filter plates. This improves operational convenience and speed. Furthermore, given the often high ceilings in many locations, replacing filter plates from outside the site, such as within ventilation ducts or above the ceiling, is more convenient and faster compared to related technologies that involve replacing filter plates from inside the site. When filter plate replacement is needed, the operator first closes the air inlet using the shielding component, then flips up the entire housing from above the fan filter, moving the filter plate away from the air inlet and thus gaining more operating space for quick and convenient filter plate replacement.

[0016] In one optional embodiment, the hinge includes a first hinge frame, a second hinge frame, and a hinge shaft. The first hinge frame is rotatably engaged with the second hinge frame via the hinge shaft. One of the first hinge frame and the second hinge frame is connected to the substrate, and the other is connected to the housing.

[0017] Beneficial effects: The hinged component completes the hinged connection and realizes the flipping action of the outer shell through the cooperation of the first hinged frame, the second hinged frame and the hinged shaft. Since the first hinged frame and the second hinged frame can be directly integrated with the corresponding base plate or outer shell, or can be connected to the corresponding base plate or outer shell through a post-installation method, the hinged component can be easily obtained by modifying the existing fan filter. With the closed structure installed at the air inlet, the existing site filter unit can be modified with a lower construction cost and time cost, so as to achieve the effect of not having to shut down the equipment in the site when replacing the filter plate.

[0018] In one alternative embodiment, the filter plate is detachably connected to the housing via a slider and a groove. When installing or removing the filter plate, the filter plate is installed or removed from the side of the housing away from the hinge.

[0019] Beneficial effects: By installing the filter plate from the side of the housing away from the hinge, the operating space for the staff to replace the filter element can be further increased, reducing the difficulty of operation and increasing the speed of disassembly and assembly.

[0020] In one optional embodiment, the shielding assembly includes a base plate and a limiting member. The base plate is disposed on one side of the housing, and one end of the shielding plate is hinged to the base plate, such that the shielding plate is adapted to flip between the shielding position and the open position. The limiting member is adapted to limit the shielding plate to the shielding position or to limit the shielding plate to the open position.

[0021] Beneficial effects: The barrier can be switched between the covered and open positions by flipping, which is simple in structure and easy to operate.

[0022] In one optional embodiment, the limiting member is two magnets respectively disposed on the upper side of the blocking position and the upper side of the opening position, and the blocking plate is provided with a metal part suitable for being attracted by the magnet.

[0023] Beneficial effects: The structure that uses magnets to attract metal parts for positioning is simple, inexpensive, and easy to operate.

[0024] Secondly, the present invention also provides a filtration unit, comprising: a plurality of the above-described fan filters.

[0025] Beneficial effects: The filtration unit employs the aforementioned fan filters. Firstly, the filter plates of each fan filter can be replaced from outside the cleanroom where the filtration unit is located, providing ample operating space. For high-ceilinged workshops, replacing filter plates from the outside eliminates the time required to move ladders or scaffolding and prevents dust from falling into the cleanroom. Secondly, the enclosed structure can seal the air inlet during filter plate replacement, preventing unfiltered air from entering the cleanroom and preventing dust falling during replacement from entering. This eliminates the need for equipment downtime within the cleanroom, significantly saving production time and improving production efficiency.

[0026] Thirdly, the present invention also provides a fresh air system, comprising: a fresh air duct; the aforementioned filter unit; the filter unit is disposed within the fresh air duct, and each of the fan filters in the filter unit is respectively disposed at the air inlet of the fresh air duct facing the room, and the air outlet of the outer casing corresponds one-to-one with and is connected to the air inlet of the fresh air duct facing the room.

[0027] Beneficial effects: By installing the above-mentioned filter units in the fresh air system, the time required to replace the filter plates of the entire filter unit of the fresh air system is greatly reduced. Furthermore, since there is no need to shut down the equipment in the fresh air system site, production efficiency can be improved and damage caused by repeated start-ups and shutdowns can be avoided. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1This is a schematic diagram of the overall structure of a fan filter under normal operating conditions according to an embodiment of the present invention;

[0030] Figure 2 for Figure 1 A magnified view of part A in the diagram;

[0031] Figure 3 This is a structural schematic diagram of a fan filter under normal operating conditions according to an embodiment of the present invention, viewed from below.

[0032] Figure 4 This is a schematic diagram of a fan filter in the state of replacing the filter plate according to an embodiment of the present invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 100. Outer shell; 101. Fan; 102. Filter plate; 200. Shielding assembly; 201. Base plate; 202. Shielding plate; 2021. Push-pull handle; 300. Hinge; 301. First hinge frame; 302. Second hinge frame; 303. Hinge shaft; 400. Support frame. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0036] Fan filters are air filtration devices that use fans to drive outdoor air through filter plates before delivering it into indoor spaces with high air cleanliness requirements. In a cleanroom, multiple fan filters form a filtration unit that works together to deliver clean air to the cleanroom. The number of fan filters in the filtration unit is determined by the area of ​​the cleanroom. Usually, fan filter units are set up in an array on the ceiling of the cleanroom, and some fan filter units can also be set up on the side walls of the cleanroom.

[0037] Filter components such as filter plates and filter elements in fan filters need to be replaced regularly to maintain their effectiveness in filtering airborne dust. Cleanrooms typically provide workplaces for equipment with high air cleanliness requirements. When filter components are replaced, the air filtration at that location will fail, and dust on the filter plates can easily fall off during the replacement process, leading to a decrease in air cleanliness. Therefore, in related technologies, it is necessary to shut down the equipment in the cleanroom to prevent abnormal equipment operation.

[0038] In addition, in modern times, in order to achieve centralized production management and large-scale production, the floor area and ceiling height of cleanrooms in factories have gradually increased. On the one hand, this makes it difficult to replace the filter plates of the fans installed at high locations. On the other hand, once it is necessary to replace the filter plates of the fans in the cleanroom, it is necessary to shut down the machines for a long time, which seriously affects production efficiency.

[0039] This application addresses the situation where replacing the filter plates of a fan filter in a cleanroom requires shutting down all equipment in the cleanroom. It proposes a fan filter, filtration unit, and cleanroom that allows for faster filter plate replacement without requiring equipment shutdown.

[0040] The following is combined Figures 1 to 4 The following describes embodiments of the present invention.

[0041] According to an embodiment of the present invention, a fan filter is provided, see below. Figures 1 to 4 The system includes: a fan 101; a filter plate 102; a housing 100 having a cavity, with an air inlet and an air outlet communicating with the cavity, the fan 101 being disposed in the cavity, and the filter plate 102 being detachably connected to the air outlet of the housing 100; and a shielding assembly 200 connected to one side of the air outlet of the housing 100, including a shielding plate 202 having a shielding position and an open position. In the shielding position, the shielding plate 202 shields the air outlet of the housing 100, and in the open position, the shielding plate 202 is away from the air outlet of the housing 100.

[0042] Specifically, this embodiment does not limit the specific form of the detachable connection between the filter plate 102 and the outer shell 100. The filter plate 102 can be slidably connected to the outer shell 100 through the cooperation of a slider and a groove, and can be separated from the outer shell 100 from the groove opening on one side of the outer shell 100. Alternatively, it can be directly snapped onto the shell wall of the outer shell 100 from the end face through the cooperation of a locking block and a locking groove. It can also be set on the outer shell 100 through other mounting structures. All of the above-mentioned detachable connection structures between the aluminum plate and the outer shell 100 are within the protection scope of this embodiment.

[0043] It should be noted that the function of the enclosed structure is to controllably close and open the air inlet of the outer casing 100, thereby preventing dust from entering the room. Its specific form can be a baffle 202, an air collecting hood with a valve, or a cloth bag or other structure set around the air inlet of the outer casing 100.

[0044] It should be further explained that the function of the clearance structure includes allowing the side of the outer casing 100 where the filter plate 102 is provided to move closer to or away from the air inlet, thereby providing operating space for the staff to replace the filter plate 102. Specifically, the outer casing 100 can be hinged to the connecting structure at the air inlet, or the outer casing 100 can be slidably connected to the connecting structure at the air inlet through guide rails and sliders, so that the outer casing 100 can be moved as a whole away from the air inlet. The connecting structure at the air inlet can be a wall at the air inlet, a bracket installed at the air inlet, or other structures. The specific forms of the clearance structure are all within the protection scope of this embodiment.

[0045] In this embodiment, by setting up the shielding component 200, when replacing the filter plate 102, the air outlet is sealed by the shielding component 200 to prevent air from entering the indoor environment from the air inlet where the filter has failed, thus preventing a decline in air quality. It also prevents dust falling from the filter plate 102 from entering the room during the replacement process. Furthermore, since the sealed structure seals the air outlet at the location where the filter plate 102 is being replaced, the other fans 101 filters in the room can continue to operate normally. Therefore, it is not necessary to shut down the equipment in the cleanroom when replacing the filter plate 102, thereby improving work efficiency.

[0046] In one embodiment, the shielding assembly 200 further includes a substrate 201, which is disposed on one side of the housing 100. The shielding plate 202 is slidably disposed on the substrate 201, and guide rails that slide in cooperation with the shielding plate 202 are provided on opposite sides of the substrate 201.

[0047] In this embodiment, by setting a substrate 201 and a baffle 202 that slide and cooperate with each other, the structure is simple, the cost is low and the operation is easy, enabling the staff to quickly control the opening or closing of the air inlet.

[0048] In one embodiment, the shield 202 is provided with a push-pull handle 2021 on the side opposite to the air inlet.

[0049] In this embodiment, by providing a push-pull handle 2021, it is easier for staff to push or pull the shield 202 from inside the cleanroom. When the fan 101 filter is located at the top of the cleanroom and the top of the cleanroom is relatively high, staff can easily operate the shield 202 even on scaffolding or ladders.

[0050] In one embodiment, a support frame 400 is also included at the blocking position of the baffle plate 202. The support frame 400 is connected to the substrate 201. The support frame 400 is adapted to abut against the air outlet side of the housing 100 to provide support for the housing 100. Slide rails that cooperate with the baffle plate 202 are provided on opposite sides inside the support frame 400. The slide rails and guide rails correspond to each other and are connected.

[0051] It should be noted that the support frame 400 can be integrally formed with the substrate 201 or it can be a separate unit. When the support frame 400 and the substrate 201 are integrally formed, the overall structural integrity and the sealing effect at the air inlet are improved, reducing the number of steps during installation and lowering the possibility of uneven installation or weakened sealing due to assembly errors. Simultaneously, the integral formation of the substrate 201 and the support frame 400 allows the slide rails and guide rails of the baffle 202 on both the substrate 201 and the support frame 400 to connect as a whole, resulting in smoother sliding of the baffle 202 between the substrate 201 and the support frame 400 and improved operational convenience.

[0052] In addition, the sliding connection structure extending on the support frame 400 can provide support for the shield 202 extending from the substrate 201, improve the load-bearing capacity of the shield 202, and prevent the possibility of the shield 202 breaking.

[0053] In this embodiment, by setting a support frame 400 at the air inlet, when the fan 101 filter group is working normally, the outer shell 100 is located on the upper side of the support frame 400 and abuts against the support frame 400. The support frame 400 provides a support base and limit for the outer shell 100, and provides support for the shield 202 when the shield 202 moves to the shielding position.

[0054] In one embodiment, the housing 100 is hinged to the substrate 201 via a hinge 300. The housing 100 has a working position and a flipped position. In the working position, the air outlet side of the housing 100 abuts against the support frame 400. In the flipped position, the housing 100 is located on the upper side of the substrate 201, and the sidewall of the housing 100 abuts against the upper sidewall of the substrate 201.

[0055] In this embodiment, by providing a hinge 300, the side of the housing 100 where the filter plate 102 is located can be moved away from the air inlet, providing ample operating space for workers to replace the filter plate 102, improving the convenience and speed of operation. Furthermore, since many sites are quite high, replacing the filter plate 102 from outside the site, such as from a ventilation duct or above the ceiling, is more convenient and faster than replacing it from inside the site in related technologies. When the filter plate 102 needs to be replaced, the worker first closes the air inlet using the shielding component 200, and then flips the entire housing 100 from above the filter of the fan 101, moving the position of the filter plate 102 on the housing 100 away from the air inlet, thereby obtaining more operating space and facilitating quick and convenient replacement of the filter plate 102.

[0056] In one embodiment, the hinge 300 includes a first hinge frame 301, a second hinge frame 302, and a hinge shaft 303. The first hinge frame 301 is rotatably engaged with the second hinge frame 302 via the hinge shaft 303. One of the first hinge frame 301 and the second hinge frame 302 is connected to the substrate 201, and the other is connected to the housing 100.

[0057] In this embodiment, the hinge 300 completes the hinge connection and realizes the action of flipping the outer shell 100 through the cooperation of the first hinge frame 301, the second hinge frame 302 and the hinge shaft 303. Since the first hinge frame 301 and the second hinge frame 302 can be directly integrated with the corresponding base plate 201 or outer shell 100, or can be connected to the corresponding base plate 201 or outer shell 100 through a post-installation method, the hinge 300 can be easily obtained by modifying the existing fan 101 filter. With the closed structure installed at the air inlet, the existing site filter unit can be modified with a lower construction cost and time cost, so as to achieve the effect of not having to shut down the equipment in the site when replacing the filter plate 102.

[0058] In one embodiment, the filter plate 102 is detachably connected to the housing 100 by the cooperation of the slider and the groove. When installing or removing the filter plate 102, the filter plate 102 is installed or removed from the side of the housing 100 away from the hinge 300.

[0059] Specifically, an insertion port is provided on the side wall of the housing 100 away from the hinge 300. One of the two channels is located on the inner side wall of the housing 100 inside the insertion port, and the other is located on the side wall of the filter plate 102. When replacing the filter plate 102, the old filter plate 102 is removed from the insertion port, and then the new filter plate 102 is inserted from the insertion port.

[0060] In this embodiment, by installing the filter plate 102 from the side of the housing 100 away from the hinge 300, the operating space for the staff to replace the filter element can be further increased, the operating difficulty can be reduced and the disassembly and assembly speed can be improved.

[0061] In one embodiment, the shielding assembly 200 includes a substrate 201 and a limiting member. The substrate 201 is disposed on one side of the housing 100. One end of the shielding plate 202 is hinged to the substrate 201, so that the shielding plate 202 is adapted to flip between a shielding position and an open position. The limiting member is adapted to limit the shielding plate 202 in the shielding position or to limit the shielding plate 202 in the open position.

[0062] Specifically, this embodiment does not limit the specific form of the limiting member. The limiting member can be a metal part that can be attracted by a magnet to limit the blocking plate 202, or it can be a metal part that can be attracted by a magnet to limit the blocking plate 202, or it can be a metal part that can limit the blocking plate 202, or it can be other structures in the prior art that can limit the flip plate structure. The specific forms of the above-mentioned limiting members are all within the protection scope of this embodiment.

[0063] In this embodiment, the switching between the blocking position and the open position of the shield 202 is achieved by flipping, which is simple in structure and easy to operate.

[0064] In one embodiment, the limiting members are two magnets respectively disposed above the blocking position and the opening position, and the blocking plate 202 is provided with a metal part suitable for being attracted by the magnets.

[0065] In this embodiment, the structure that achieves positioning by using a magnet to attract the metal part is simple, inexpensive, and easy to operate.

[0066] According to an embodiment of the present invention, in another aspect, a filtration unit comprising a plurality of the above-described fan filters is also provided.

[0067] In this embodiment, the filtration unit uses the aforementioned fan filters. Firstly, the filter plates 102 of each fan filter in the filtration unit can be replaced from outside the cleanroom area where the filtration unit is located, providing ample operating space. Furthermore, for factories with high ceilings, replacing the filter plates 102 from the outside eliminates the time required to move ladders or scaffolding, and prevents dust from falling into the cleanroom area. Secondly, the enclosed structure can block the air inlet of the cleanroom area when replacing the filter plates 102, preventing unfiltered air from entering the cleanroom area and preventing dust falling during filter plate replacement from entering. This eliminates the need for equipment shutdown in the cleanroom, significantly saving production time and improving production efficiency.

[0068] According to an embodiment of the present invention, another aspect provides a fresh air system, including a filter unit disposed in a fresh air duct, wherein each fan filter in the filter unit is disposed at the air inlet of the fresh air duct facing the room, and the air outlet of the outer casing 100 corresponds to and is connected to the air inlet of the fresh air duct facing the room.

[0069] In this embodiment, by setting the above-mentioned filter unit in the fresh air system, the time required to replace the filter plates of the entire filter unit of the fresh air system is greatly reduced. Furthermore, since there is no need to shut down the equipment in the fresh air system site, production efficiency can be improved and damage caused by repeated start-ups and shutdowns can be avoided.

[0070] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A fan filter, characterized in that, include: Fan (101); Filter plate (102); The outer casing (100) has a cavity and is provided with an air inlet and an air outlet communicating with the cavity. The fan (101) is located in the cavity, and the filter plate (102) is detachably connected to the air outlet of the outer casing (100). A shielding assembly (200) is connected to the air outlet side of the housing (100) and includes a shielding plate (202). The shielding plate (202) has a shielding position and an open position. In the shielding position, the shielding plate (202) shields the air outlet of the housing (100). In the open position, the shielding plate (202) leaves the air outlet of the housing (100). The shielding assembly (200) further includes a substrate (201), and the housing (100) is hinged to the substrate (201) via a hinge (300). The housing (100) has a working position and a flip position. In the flip position, the housing (100) is located on the upper side of the substrate (201), and the sidewall of the housing (100) abuts against the upper sidewall of the substrate (201).

2. The fan filter according to claim 1, characterized in that, The substrate (201) is disposed on one side of the outer shell (100), and the shield (202) is slidably disposed on the substrate (201). The substrate (201) has guide rails on opposite sides that slide in cooperation with the shield (202).

3. The fan filter according to claim 2, characterized in that, The shield (202) has a push-pull handle (2021) on the side opposite to the base plate (201).

4. The fan filter according to claim 2, characterized in that, It also includes a support frame (400) located at the shielding position of the shielding plate (202). The support frame (400) is connected to the base plate (201) and integrally formed. The support frame (400) is adapted to abut against the air outlet side of the outer shell (100) to provide support for the outer shell (100). Slide rails that cooperate with the shielding plate (202) are provided on opposite sides inside the support frame (400). The slide rails correspond one-to-one with the guide rails and are connected.

5. The fan filter according to claim 4, characterized in that, In the working position, the air outlet side of the housing (100) abuts against the support frame (400).

6. The fan filter according to claim 5, characterized in that, The hinge (300) includes a first hinge frame (301), a second hinge frame (302), and a hinge shaft (303). The first hinge frame (301) is rotatably engaged with the second hinge frame (302) through the hinge shaft (303). One of the first hinge frame (301) and the second hinge frame (302) is connected to the substrate (201), and the other is connected to the outer shell (100).

7. The fan filter according to claim 6, characterized in that, The filter plate (102) is detachably connected to the housing (100) through the cooperation of the slider and the groove. When the filter plate (102) is installed or removed, the filter plate (102) is installed or removed from the side of the housing (100) away from the hinge (300).

8. The fan filter according to claim 1, characterized in that, The shielding assembly (200) includes a base plate (201) and a limiting member. The base plate (201) is disposed on one side of the housing (100). One end of the shielding plate (202) is hinged to the base plate (201) so that the shielding plate (202) is adapted to flip between the shielding position and the open position. The limiting member is adapted to limit the shielding plate (202) to the shielding position or to limit the shielding plate (202) to the open position.

9. The fan filter according to claim 8, characterized in that, The limiting member consists of two magnets respectively disposed on the upper side of the blocking position and the upper side of the opening position, and the blocking plate (202) is provided with a metal part suitable for being attracted by the magnet.

10. A filtration unit, characterized in that, include: The fan filter according to any one of claims 1 to 9.

11. A fresh air system, characterized in that, include: Fresh air ducts; The filtration unit as described in claim 10; The filter unit is located inside the fresh air duct, and each of the fan filters in the filter unit is located at the air inlet of the fresh air duct facing the room. The air outlet of the outer casing (100) corresponds to and is connected to the air inlet of the fresh air duct facing the room.

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