A device for preventing backflow of a fan

Abstract

The utility model relates to a ventilation equipment technical field discloses a device for preventing fan backflow, including mounting panel, fixedly connected with the pipe one of mounting panel front side, and fixedly connected with the connecting body of mounting panel back side, the fan is rotatively connected in the pipe one inside, the flange plate two is fixedly connected with the pipe one front side, the device still includes the pipe two, the flange plate one is fixedly connected with the pipe two front side, the pipe one is connected with the pipe two through the flange plate one and the flange plate two screw thread, the connecting body front side fixedly connected with the fixed plate of magnet two, the connecting body inside is provided with the louver of magnet one, the utility model discloses through the magnetic adsorption principle control louvre opening and closing, effectively solved the problem of outside airflow backflow when fan shutdown, and through split type flange structure has realized the convenient disassembly maintenance of fan, has good sealing, prevents backflow reliable, will be in cleaning maintenance etc.

Description

Technical Field

[0001] This utility model relates to the field of ventilation equipment technology, and in particular to a device for preventing backflow of air from a fan. Background Technology

[0002] As a common ventilation device, fans are widely used in industrial plants, commercial buildings, and residential buildings to remove indoor polluted air or transport fresh air. In practical applications, fans are connected to the outdoor environment through ducts. When the fan is working normally, the airflow flows unidirectionally from the inside to the outside. However, when the fan stops working, if the outdoor wind pressure is greater than the indoor air pressure, the outside airflow often flows back into the room through the exhaust duct. This backflow phenomenon not only brings outdoor dust, odors, and hot and cold air into the room, disrupting the indoor air quality and temperature balance, but also causes the fan blades to reverse under the action of the reverse airflow, damaging the motor.

[0003] To address this issue, existing ventilation ducts are equipped with gravity check valves or louvers at their ends. These devices rely on the weight of the blades themselves to naturally droop and close when the fan stops. However, relying solely on gravity for closure has significant limitations. The closing force is relatively weak, and the sealing performance is poor. In windy weather, strong winds can easily blow the blades open, causing backflow, or the blades can continuously impact the frame, producing annoying slapping noise. Furthermore, existing fan duct structures are mostly formed by integrated welding and riveting. Once a large amount of dust accumulates on the internal fan blades and needs cleaning, or when the motor malfunctions and needs repair, it is often impossible to directly access the internal components. The entire duct system must be dismantled, making maintenance extremely inconvenient.

[0004] Therefore, this utility model proposes a device to prevent backflow of air from a fan, in order to overcome the shortcomings of the prior art. Utility Model Content

[0005] In view of the problems existing in the technology of preventing backflow of air from fans, such as the inability to seal properly when the fan stops due to reliance on gravity for closure, the inability to be affected by external airflow and the resulting backflow or slapping noise, and the difficulty in accessing the internal fan of the traditional integrated duct structure and the inconvenience of cleaning dust accumulation and maintenance after long-term use, this utility model aims to provide a device with an improved structure that can effectively solve the above problems and prevent backflow of air from fans.

[0006] This utility model provides a device for preventing backflow of air from a fan, comprising: a mounting plate, a circular tube fixedly connected to the front side of the mounting plate, and a connecting body fixedly connected to the rear side of the mounting plate. A fan is rotatably connected inside the circular tube, and a fixed plate and movable louvers are disposed on the front side of the connecting body and disposed inside the connecting body.

[0007] The fixed plate has a slot on its surface, a magnet is fixedly placed inside the slot, and a magnet is fixedly connected to the bottom of the louver.

[0008] Furthermore, a flange is fixedly connected to the front side of the first round tube, and the device also includes a second round tube, with a flange fixedly connected to the front side of the second round tube. The first round tube and the second round tube are connected by threads through the flange and the flange. The louver is magnetically connected through the magnet and the magnet, and the magnetic attraction is used to achieve a closed seal.

[0009] Preferably, a reinforcing plate is fixedly connected at the connection between the first round tube and the mounting plate. The reinforcing plate is connected between the outer wall of the first round tube and the front surface of the mounting plate. By increasing the connection area and support points, the structural strength and seismic performance of the connection part can be effectively improved, and loosening caused by fan vibration can be prevented.

[0010] Preferably, a filter screen is fixedly connected inside the second circular tube. The filter screen covers the internal airflow channel of the second circular tube and is used to intercept dust, insects and debris before air enters the core components of the device, thus protecting the cleanliness and normal operation of the internal fan and anti-backflow components.

[0011] Preferably, a blade is fixedly connected to the rear side of the inside of the connector. The blade is located behind the louver and is inclined downwards, serving as a second physical defense line. Its inclined angle is used to block and guide the backflow of air that may leak.

[0012] Preferably, a baffle is fixedly connected to the upper side of the connector. The baffle is inclined and extends downward and backward to block rainwater from directly entering the device and to drain the rainwater in time through the inclined surface.

[0013] Preferably, the top of the louver is rotatably connected to the top of the inner wall of the connector, and the louver can swing backward relative to the fixed plate under wind pressure so that the first magnet moves away from the second magnet, thereby realizing a one-way opening function.

[0014] Preferably, the shape of the slot on the fixing plate is adapted to the shape of the second magnet, and the second magnet is fixedly installed in the slot to ensure that the magnet is firmly installed and the surface is flat, thus ensuring the adsorption effect.

[0015] Preferably, the first flange and the second flange are fixedly connected by a bolt assembly, which passes through the through holes aligned on the first flange and the second flange, enabling quick assembly and disassembly of the air inlet pipe section.

[0016] Preferably, the connection between the connector and the mounting plate is provided with a through hole that connects the circular tube to the interior of the connector. Airflow is delivered by the fan through the through hole into the connector, ensuring the continuity of the airflow channel.

[0017] This utility model has the following beneficial effects: 1. This utility model solves the problems in the prior art where, when the fan stops working, the external airflow cannot be tightly closed due to gravity alone, resulting in backflow, indoor and outdoor heat exchange, and slapping noise. It achieves the effect of automatic tight closure in the absence of wind, effectively blocking the return of external airflow, and significantly improving the sealing performance of the device.

[0018] 2. This utility model solves the problems of difficult access to the internal fan, difficulty in cleaning dust accumulation after long-term use, and inconvenience in motor maintenance and replacement by designing the air inlet pipe and the fan mounting pipe as independent separate structures and using flange and bolt assembly for detachable connection. It achieves the effect of quick disassembly and separation, easy access for staff to clean and maintain the fan, and greatly reduces the difficulty and cost of daily maintenance.

[0019] 3. This utility model solves the problems of external dust and impurities being sucked in by the airflow and damaging the fan rotating parts, as well as rainwater directly entering the device and causing water accumulation and corrosion, by setting a full-coverage filter at the air inlet and an inclined baffle at the top of the air outlet. It achieves the effect of providing all-round protection for the internal core structure, effectively intercepting foreign objects and timely guiding and draining rainwater, and extending the overall service life of the device. Attached Figure Description

[0020] Figure 1 This is a perspective view of a device for preventing backflow of air from a fan, as proposed in this utility model. Figure 2 This is a front view of a device for preventing backflow of air from a fan, as proposed in this utility model. Figure 3 This is a split view of the circular pipe 1 and circular pipe 2 in the device for preventing backflow of air from a fan proposed in this utility model. Figure 4 This is a cross-sectional view of the connecting body in a device for preventing backflow of air from a fan, as proposed in this utility model.

[0021] Legend: 1. Mounting plate; 2. Round tube one; 3. Round tube two; 4. Flange one; 5. Filter screen; 6. Fan; 7. Flange two; 8. Reinforcing plate; 9. Connector; 10. Baffle; 11. Blade; 12. Louver; 13. Magnet one; 14. Magnet two; 15. Fixing plate. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Example:

[0023] Please refer to Figures 1 to 4 This utility model provides a device to prevent backflow of air from a fan, which aims to solve the structural defects in the prior art that the fan cannot effectively block the backflow of external airflow when it stops working, resulting in the entry of impurities, and that the traditional integrated duct structure is not easy to disassemble and clean up the accumulated dust.

[0024] like Figure 1 and Figure 2 As shown, the device for preventing backflow of air from the fan includes a mounting plate 1 and a circular pipe 2 fixedly connected to the front side of the mounting plate 1. The mounting plate 1 serves as the mounting base for the entire device, used to fix and support various components and to install them against the wall. The circular pipe 2 serves as the main air intake channel, carrying the internal structure. Inside the circular pipe 2, a fan 6 is rotatably connected via bearings or brackets. The fan 6 serves as a power source, used to generate negative pressure after being powered on, drawing in air and delivering airflow backward. A connector 9 is welded or bolted to the rear side of the mounting plate 1. The connector 9 is coaxially arranged with the circular pipe 2 and serves as the installation carrier for the exhaust channel and the anti-backflow structure. A reinforcing plate 8 is welded and fixedly connected between the outer wall of the connection between the circular pipe 2 and the mounting plate 1 and the front surface of the mounting plate 1. The reinforcing plate 8 is evenly distributed in a triangular structure to enhance the structural strength and toughness of the connection between the circular pipe 2 and the mounting plate 1, preventing the connection from loosening due to long-term vibration of the fan 6.

[0025] like Figure 3As shown, a flange 7 is welded or integrally formed and fixedly connected to the front side of the circular tube 2. The device also includes an independently set circular tube 3, which serves as an extension of the air inlet to guide external air in. A flange 4 is fixedly connected to the front side of the circular tube 3. Both flange 4 and flange 7 have aligned mounting holes on their surfaces. The circular tube 2 and circular tube 3 are fastened by bolt assemblies passing through the mounting holes on flange 4 and flange 7. This split flange connection structure allows the circular tube 3 to be quickly disassembled from the circular tube 2, making it convenient for staff to directly access and clean the blades of the fan 6 located inside the circular tube 2 or to replace and maintain the motor. A filter 5 is fixedly connected inside the circular tube 3 by screws or clips. The filter 5 completely covers and cuts off the internal passage of the circular tube 3 perpendicular to the airflow direction to prevent external dust, leaves, and other impurities from entering the device with the airflow before the air enters the fan 6, thereby effectively protecting the rotating parts of the fan 6 and the internal structure of the subsequent connecting body 9.

[0026] To solve the technical problem of backflow of external air when the fan stops working, the core of the technical solution of this embodiment is that the device for preventing backflow of air from the fan also includes an anti-backflow component designed based on the principle of magnetic adsorption. Furthermore, the anti-backflow component forms a specific rotational fit and magnetic attraction connection with the connecting body 9 and the fixing plate 15.

[0027] Please refer to Figure 3 and Figure 4 The core structure is described in detail below. A fixing plate 15 is fixedly connected to the front of the connecting body 9 by welding or screws. The surface of the fixing plate 15 has a groove, which is rectangular or circular in shape. A magnet 14 is fixedly installed inside the groove by adhesive or interference fit. A louver 12 is movably installed inside the connecting body 9. The louver 12 is used as the main blocking component to control the opening and closing of the channel according to the change of wind pressure. A magnet 13 is fixedly connected to the bottom of the louver 12 by adhesive or slot. The top of the louver 12 is rotatably connected to the top of the inner wall of the connecting body 9 by a rotating shaft. The louver 12 can swing backward relative to the fixing plate 15 under the action of wind pressure to open the channel or swing forward under the action of gravity and magnetic force to close the channel. The louver 12 is magnetically connected by the magnetic attraction between the magnet 13 and the magnet 14. When the fan 6 stops working, the magnet 13 and the magnet 14 attract each other, so that the louver 12 is tightly attached to the surface of the fixing plate 15, thereby effectively preventing the backflow of external airflow into the device.

[0028] Meanwhile, a blade 11 is welded or integrally formed and fixedly connected to the rear side of the connecting body 9. The blade 11 is located downstream of the airflow of the louver 12 and is inclined downward. The blade 11 serves as a second line of defense to guide the normally discharged airflow and assist in blocking the backflow airflow that may leak. When the louver 12 is accidentally not completely closed, the inclined blade 11 can use its physical angle to block the external direct airflow from penetrating into the device. A baffle 10 is welded or riveted and fixedly connected to the upper side of the connecting body 9. The baffle 10 is inclined and extends downward to cover the rear outlet of the connecting body 9. The baffle 10 is used to block rainwater from directly entering the interior of the connecting body 9 and guides the rainwater backward in time through its inclined surface to prevent rainwater from accumulating or backflowing and damaging the internal structure. Through the multiple protective structures of the baffle 10, blade 11 and magnetic louver 12, the device for preventing backflow of wind from the fan can maintain good sealing and protective performance in various severe weather conditions and shutdown states.

[0029] As a preferred embodiment, in order to enhance the structural stability of the connection between the circular tube 2 and the mounting plate 1 and to prevent loosening of the connection due to long-term vibration of the fan 6, please refer to... Figure 1 and Figure 2 The reinforcing plate 8 is a triangular structure connected between the outer wall of the circular tube 2 and the front surface of the mounting plate 1. The reinforcing plate 8 is preferably made of metal and is integrally welded to the circular tube 2 and the mounting plate 1. Through the mechanical stability principle of the triangle, stress is effectively dispersed, thereby improving the seismic resistance and service life of the overall structure.

[0030] As another preferred embodiment, to prevent external impurities from entering the device and damaging the fan 6 or affecting the normal operation of the subsequent anti-backflow components, please refer to... Figure 3 A filter screen 5 is fixedly connected inside the second round tube 3. The filter screen 5 cuts off the internal channel of the second round tube 3 perpendicular to the airflow direction and its edge is sealed to the inner wall of the second round tube 3. The filter screen 5 is preferably made of stainless steel or nylon. Its mesh size is set according to the actual use environment to take into account both ventilation and filtration effect, so as to effectively intercept foreign objects such as dust, insects and fallen leaves while allowing air circulation.

[0031] As another preferred embodiment, to facilitate the modular disassembly and assembly of the device for cleaning and maintenance of the internal fan 6, please refer to... Figure 3 Flange 1 4 and Flange 2 7 are detachably connected by bolts passing through aligned mounting holes. A rubber sealing gasket can also be installed between Flange 1 4 and Flange 2 7 to enhance the airtightness of the interface and prevent air leakage. This design allows the fan 6 inside the round tube 1 2 to be exposed simply by removing the bolt assembly and taking off the round tube 2 3 when the fan 6 blades are dusty or the motor needs maintenance. The operation is simple and quick.

[0032] As another preferred embodiment, in order to ensure the sealing and durability of the anti-backflow structure, the shape of the slot on the fixing plate 15 is adapted to the shape of the magnet 14. The magnet 14 is firmly embedded in the slot by strong adhesive or interference fit to prevent it from falling off after long-term use. At the same time, the magnetic strength of the magnet 13 and the magnet 14 is matched to ensure that they can be tightly attracted and closed in the windless state, and also ensure that the louvers 12 can be pushed open sensitively under the wind pressure generated by the fan 6 when it is started, without causing excessive exhaust resistance.

[0033] Working principle: When the fan 6 is powered on, the fan 6 rotates at high speed and generates a backward air pressure. The air pressure acts on the surface of the louver 12. When the air pressure torque is greater than the magnetic attraction torque between magnet 13 and magnet 2 14 and the gravitational torque of the louver 12 itself, the louver 12 is pushed by the airflow to swing backward and upward around its top fulcrum. This causes magnet 13 at the bottom of the louver 12 to move away from magnet 2 14 in the slot of the fixed plate 15. At this time, the louver 12 is in the open state, the channel is unobstructed, and the external air first passes through the filter 5 inside the circular tube 2 3. The filter 5 intercepts impurities such as dust, fallen leaves and insects in the air. The purified air then enters the interior of the circular tube 2 and is transported to the interior of the connecting body 9 under the drive of the rotating fan 6. The airflow is smoothly sent out after being guided by the open louver 12 and the blade 11 behind it, realizing the normal exhaust and ventilation function. When the fan 6 stops rotating due to power failure, the air pressure inside the circular tube 2 and the connector 9 disappears rapidly. The louver 12 loses the thrust support of the air pressure and naturally falls back to its original position under its own gravity. At the same time, as the louver 12 approaches the closed position, the magnet 13 enters the effective magnetic attraction range of the magnet 2 14. The magnetic attraction between the two causes the bottom of the louver 12 to be quickly and tightly attracted and attached to the surface of the fixed plate 15. The louver 12 then closes completely. This magnetic closing method is tighter and more secure than the closing method that relies solely on gravity. It can effectively resist the thrust of the external reverse airflow, thereby preventing the external airflow from flowing back into the device and preventing indoor and outdoor heat exchange and the return of external polluted air. When extreme weather or unexpected situations cause magnet 13 to fail to fully engage with magnet 214, even if a small amount of backflow air enters the interior of the connector 9, this airflow will be blocked and guided again by the inclined blades 11 on the rear side of the interior of the connector 9. The physical barrier formed by the blades 11 further prevents the backflow air from penetrating deep into the device and blowing directly into the fan 6 and the room. At the same time, the inclined baffle 10 at the top of the connector 9 can block rainwater from entering from above and guide the rainwater to the rear and downward to prevent rainwater accumulation or backflow, thus achieving all-round protection. Furthermore, after the device has been used for a period of time, if it is found that dust accumulates on the surface of the fan 6, affecting efficiency, or if the fan 6 malfunctions and needs to be replaced, the staff does not need to disassemble the entire device. They only need to loosen and remove the bolt assembly connecting flange 1 4 and flange 2 7, separate the round tube 2 3 from the round tube 1 2, and then directly clean or disassemble and replace the exposed fan 6. After the operation is completed, the round tube 2 3 can be reset and tightened through the flange. This greatly simplifies the daily maintenance process and reduces the difficulty and cost of maintenance.

Claims

1. A device for preventing backflow of air from a fan, comprising a mounting plate (1), a circular tube (2) fixedly connected to the front side of the mounting plate (1), and a connector (9) fixedly connected to the rear side of the mounting plate (1), wherein a fan (6) is rotatably connected inside the circular tube (2). Its features are, The front side of the first round tube (2) is fixedly connected to the second flange (7). The device also includes a second round tube (3), the front side of which is fixedly connected to the first flange (4). The first round tube (2) and the second round tube (3) are threadedly connected to the first flange (4) and the second flange (7). A fixing plate (15) is fixedly connected to the front side of the connector (9). The fixing plate (15) has a slot. A magnet (14) is placed inside the slot. A louver (12) is provided inside the connector (9). A magnet (13) is fixedly connected to the bottom of the louver (12). The louver (12) is magnetically connected to the magnet (14) through the magnet (13).

2. The device for preventing backflow of air from a fan according to claim 1, characterized in that, A reinforcing plate (8) is fixedly connected at the connection between the circular tube (2) and the mounting plate (1). The reinforcing plate (8) is connected between the outer wall of the circular tube (2) and the front surface of the mounting plate (1).

3. The device for preventing backflow of air from a fan according to claim 1, characterized in that, A filter screen (5) is fixedly connected inside the second round tube (3), and the filter screen (5) covers the internal airflow channel of the second round tube (3).

4. The device for preventing backflow of air from a fan according to claim 1, characterized in that, The connecting body (9) has a blade (11) fixedly connected to its rear side. The blade (11) is located behind the louver (12) and is inclined downward.

5. The device for preventing backflow of air from a fan according to claim 1, characterized in that, A baffle (10) is fixedly connected to the upper side of the connector (9). The baffle (10) is inclined and extends downward and backward.

6. The device for preventing backflow of air from a fan according to claim 1, characterized in that, The top of the louver (12) is rotatably connected to the top of the inner wall of the connector (9). The louver (12) can swing backward relative to the fixed plate (15) under wind pressure so that the first magnet (13) moves away from the second magnet (14).

7. The device for preventing backflow of air from a fan according to claim 1, characterized in that, The shape of the slot on the fixing plate (15) is adapted to the shape of the second magnet (14), and the second magnet (14) is fixedly installed in the slot.

8. The device for preventing backflow of air from a fan according to claim 1, characterized in that, The first flange (4) and the second flange (7) are fixedly connected by a bolt assembly, which passes through the through holes aligned on the first flange (4) and the second flange (7).

9. The device for preventing backflow of air from a fan according to claim 1, characterized in that, The connection between the connector (9) and the mounting plate (1) is provided with a through hole that connects the round tube (2) and the interior of the connector (9). Airflow is delivered by the fan (6) through the through hole and enters the connector (9).

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