An exhaust fan

Abstract

The application discloses an exhaust fan and belongs to the technical field of air conditioning and ventilation. The exhaust fan comprises an inner casing, the inner casing comprises a support base, a front guardrail is arranged at an air inlet of the support base, an air duct is connected to the rear end of the support base, a fan blade is arranged in the air duct, a dust screen is arranged at the front end of the support base and covers the air inlet, two winding shaft rollers are arranged at the two sides of the air duct, the two ends of the dust screen are wound on the winding shaft rollers, the dust screen can reciprocally wind between the two winding shaft rollers, a brushing mechanism for cleaning the dust screen and a drying mechanism for drying the dust screen are sequentially arranged between the support base and the winding shaft rollers, an outer casing is arranged outside the inner casing, and a control screen is arranged at the bottom of the outer casing. The exhaust fan overcomes the defects that the filter screen must be cleaned or replaced after the machine is stopped and disassembled, the dust screen is driven to reciprocally walk between the two winding shaft rollers through the winding shaft rollers, the regeneration cleaning of the filter screen can be completed without interrupting the operation of the exhaust fan, and the accumulation of dirty air or the deterioration of the production environment caused by stopping the machine is avoided.

Description

Technical Field

[0001] This invention relates to the field of air conditioning and ventilation technology, specifically to an exhaust fan. Background Technology

[0002] An exhaust fan is an air conditioning appliance that uses an electric motor to drive the fan blades to rotate and create airflow, thus exchanging indoor and outdoor air. The purpose of exhaust is to remove stale indoor air and regulate temperature and humidity; it is widely used in homes and public places.

[0003] In practical applications, especially in kitchens, newly renovated residences, farms, or dusty workshops, the air often contains large amounts of oil, dust, particulate matter, and even harmful volatile substances. To prevent these pollutants from being directly emitted into the outdoor environment, or to avoid them adhering to the core components of exhaust fans such as fans and motors, affecting the lifespan and performance of the equipment, existing technologies have introduced solutions such as installing filters or filter plates at the air inlet of exhaust fans. For example, patent CN216432009U discloses an exhaust fan that can filter oil fumes, and patent CN218722051U discloses an intelligent purification exhaust fan, both of which use a sliding plug-in method to install filters to intercept oil and dust.

[0004] After prolonged use, filters or filter plates accumulate a large amount of pollutants, leading to filter blockage, increased ventilation resistance, and decreased purification efficiency. At this point, the filter must be cleaned or replaced. Current maintenance procedures typically require manual disassembly: first, the exhaust fan power is turned off, the dirty filter is manually removed, cleaned, dried, and then reinstalled, or a new filter is replaced. This entire maintenance process is not only cumbersome, labor-intensive, and time-consuming, but most importantly, the exhaust fan must be shut down. In places requiring continuous ventilation (such as farms, 24-hour kitchens, or spaces requiring continuous deodorization), downtime maintenance directly leads to a deterioration of indoor air quality, affecting normal work or living environments. Therefore, how to achieve automatic cleaning or replacement of filter components without interrupting the normal operation of the exhaust fan has become a pressing technical challenge in this field. Summary of the Invention

[0005] This invention addresses the aforementioned shortcomings of existing technologies by providing an exhaust fan that enables automatic cleaning, drying, and regeneration of the filter components without shutting down the machine for continuous operation. This significantly reduces the burden of manual maintenance and ensures air purification performance in harsh or continuously ventilated environments.

[0006] To achieve the above objectives, the present invention provides the following technical solution: An exhaust fan includes an inner casing, which includes a support base. The support base has a front guardrail at its air inlet, and an air duct is connected to its rear end. Fan blades are installed inside the air duct. A dustproof net is installed at the front end of the support base to block the air inlet. Roller rollers are installed on both sides of the air duct, and the two ends of the dustproof net are wound around the rollers. The dustproof net can be wound back and forth between the two rollers. A brushing mechanism for cleaning the dustproof net and a drying mechanism for drying the dustproof net are sequentially provided between the support base and the rollers. An outer casing is fitted over the inner casing, and a control panel is installed at the bottom of the outer casing.

[0007] Preferably, a rear grille is provided at the rear opening of the outer casing, the rear grille includes evenly spaced baffles, and a first motor is provided inside the outer casing to drive the baffles to rotate synchronously. Preferably, the upper and lower ends of the support base are provided with guide grooves that cooperate with the ends of the dustproof net, the two ends of the support base are provided with tension rollers that support the dustproof net, the upper ends of the two rollers are connected by a synchronous belt, and a third motor that drives the rollers to rotate is provided inside the outer casing.

[0008] Preferably, the washing mechanism includes a water collection box that is wider at the top and narrower at the bottom. The outer casing contains a water box, which contains a sewage tank and a clean water tank. The upper end of the water box has a water inlet that communicates with the sewage tank, and the lower end of the water box has a drain outlet that connects with the water inlet. A dustproof net passes horizontally through the water collection box. The water collection box contains a roller brush that washes both sides of the dustproof net. The roller brush is driven by a second motor. A spray pipe is located above the roller brush. A water pump is located at the upper end of the water box. The water pump draws water from the clean water tank into the spray pipe.

[0009] Preferably, the water collection box is provided with an inclined scraper, which is elastic and presses against both sides of the dustproof net. Water-absorbing cotton is provided behind the scraper, and the water-absorbing cotton and the scraper are fixed to the water collection box by a support rod.

[0010] Preferably, the air drying mechanism includes an air collecting groove fixed on the inner wall of the air duct, the air collecting groove is connected to a flow equalization pipe through an air duct, the flow equalization pipe is located on the outside of the air duct, the side wall of the flow equalization pipe is provided with an air outlet facing the dustproof net, and the side wall of the outer casing is provided with a vent corresponding to the position of the air outlet.

[0011] Preferably, the air collecting groove is a semi-circular ring structure, with the opening of the air collecting groove facing the fan blade, and both ends of the air collecting groove are closed structures.

[0012] Preferably, the flow equalization pipe is vertically located on one side of the dustproof net, the length of the flow equalization pipe is not less than the width of the dustproof net, a perforated flow equalization plate is vertically provided in the middle of the flow equalization pipe, and the air duct and air outlet are located on both sides of the flow equalization plate.

[0013] Preferably, a positioning element connected to the outer casing is provided near the roller, and the end of the positioning element is provided with a positioning groove for guiding the upper or lower end of the dustproof net.

[0014] Preferably, the outer side of the outer casing is fitted with a mounting base with mounting holes.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. Achieve automatic cleaning without stopping the machine, ensuring continuous ventilation. This invention overcomes the shortcomings of existing technologies that require machine shutdown and disassembly for cleaning or replacing the filter. The dust filter is driven by rollers to reciprocate between two rollers. The dirty section automatically enters the washing and drying area, while the clean section is simultaneously replaced at the air inlet. Therefore, in locations requiring 24-hour continuous ventilation, the exhaust fan can regenerate and clean the filter without interrupting operation, avoiding the accumulation of polluted air or deterioration of the production environment due to machine shutdown.

[0016] 2. High degree of automation, significantly reducing manual maintenance costs. Users only need to set the cleaning cycle or walking mode through the control panel, and the controller can automatically coordinate the third motor (driving the roller), the second motor (driving the brush), and the water pump (spraying) to work together to complete the entire process of positioning the dirty section, spraying and scrubbing, scraping water, sucking dry, air drying, and positioning the clean section. At the same time, the clean water tank and the wastewater tank adopt a drawer-type structure, which allows users to pull them out at any time to replace the cleaning solution or empty the waste liquid without turning off the power or disassembling the machine, truly achieving non-stop maintenance and significantly reducing the labor and time costs of equipment operation and maintenance.

[0017] 3. A three-stage cleaning process and zero-energy drying ensure long-lasting cleanliness of the dustproof net. For cleaning, a roller brush simultaneously washes both sides of the net, combined with a spray nozzle, effectively removing oil, dust, lint, and other adhering substances. Subsequently, an elastic scraper mechanically removes most residual water droplets. Absorbent cotton further absorbs any remaining water film, preventing moisture from entering the winding area. For drying, the drying mechanism cleverly utilizes the high-speed airflow generated by the exhaust fan blades. Through air collection channels, ducts, distribution pipes, and nozzles, the airflow is evenly distributed to the cleaned dustproof net. No additional fans or heating elements are needed, making it both energy-efficient and safe, effectively preventing the dustproof net from becoming moldy or breeding bacteria due to moisture.

[0018] 4. Offers two intelligent cleaning modes to flexibly adapt to different usage scenarios. The first is a reciprocating cycle operation mode, suitable for situations where the dust filter length is limited and the overall structure is compact. Each cleaning cycle alternates the direction of travel, with the two working sections taking turns performing filtration and cleaning tasks, achieving regular and efficient cyclical self-cleaning. The second is a unidirectional cumulative travel followed by a reverse travel mode, suitable for scenarios where the total length of the dust filter is much greater than the width of the working area. This fully utilizes the long filter reserve, reduces the cleaning frequency, and ensures that the filter surface in front of the air inlet is always completely replaced, avoiding the mixing of new and old filters.

[0019] 5. The compact and reliable structural design ensures stable operation of the dustproof net. Guide grooves prevent the net from shifting vertically, and springs push the tension rollers to consistently press against the back of the net, ensuring a flat and taut surface and preventing filtration failure or jamming caused by wrinkles or looseness. The winding rollers are driven by a synchronous belt, requiring only one third motor to achieve synchronous forward and reverse winding of two rollers, resulting in a simple structure and reliable control. Positioning components and grooves ensure neat stacking of the dustproof net during winding, preventing deviation and edge curling, thus extending the service life of the dustproof net.

[0020] 6. Enhanced overall machine protection and operational safety. The front guardrail prevents hard foreign objects from directly impacting the dust filter and damaging the fan's internal components, thus improving operational safety. The rear grille automatically closes when the exhaust fan is not operating, effectively blocking outdoor insects and debris and preventing backflow; it automatically opens during operation to ensure smooth airflow. These designs protect the internal core components and prevent adverse interference from the external environment on the normal operation of the exhaust fan.

[0021] 7. Easy to install and operate, highly adaptable. The mounting base has mounting holes, allowing the entire unit to be easily fixed to walls, window openings, or other installation locations, adapting to different building structures. The control panel integrates a controller, providing a user-friendly interface and intuitive parameter settings. This allows users to easily check equipment status, adjust cleaning parameters, or manually control various actuators at any time, enhancing the product's practicality and user experience. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the structure when the rear grille is open; Figure 3 This is a schematic diagram of the structure when the rear grille is closed; Figure 4 This is a schematic diagram of the internal casing. Figure 5 This is a schematic diagram of the installation structure of the tension roller; Figure 6 This is a schematic diagram of the internal structure of the present invention; Figure 7 This is a cross-sectional view of the present invention; Figure 8 This is a schematic diagram of the brushing mechanism. Figure 9 This is a schematic diagram of the water tank structure; Figure 10 A schematic diagram of the structure of the roller brush and the dustproof net in combination; Figure 11 This is a structural schematic diagram of the positioning component; Figure 12 This is a three-dimensional structural diagram of the present invention after the outer casing has been removed; Figure 13 This is a rear view of the present invention after the outer casing has been removed; Figure 14 Schematic diagram of the air-drying mechanism; Figure 15 This is a cross-sectional view of the air-drying mechanism; Figure 16 This is a schematic diagram of the wiper assembly. In the diagram: 1-Outer casing; 101-Mounting base; 102-Control panel; 103-Baffle; 104-Air vent; 105-First motor; 106-Positioning component; 107-Positioning groove; 2-Water box; 201-Sewage tank; 202-Water inlet; 203-Water pump; 204-Clear water tank; 3-Inner casing; 301-Support base; 302-Air duct; 303-Tension roller; 304-Guide groove; 305-Front guardrail; 306-Slide groove; 307-Spring; 4-Dustproof net; 5-Brushing mechanism; 501-Water collection box; 502-Roll brush; 503-Second motor; 504-Spray pipe; 505-Scraper; 506-Absorbent cotton; 507-Drain outlet; 508-Support rod; 6-Drying mechanism; 601-Air collection trough; 602-Air duct; 603-Flow equalization pipe; 604-Air outlet; 605-Flow equalization plate; 7-Roller roller; 701-Third motor; 702-Synchronous belt. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] like Figure 1 As shown, an exhaust fan capable of automatic cleaning without stopping operation includes an outer casing 1 and an inner casing 3 fitted inside it. A rear grille is provided at the rear opening of the outer casing 1, as shown in the figure. Figure 2 , 3As shown, the rear grille consists of multiple vertically spaced baffles 103. All baffles 103 are connected to the output shaft of the first motor 105 via connecting rods. When the first motor 105 rotates, it can drive all baffles 103 to rotate synchronously. When the exhaust fan is not working, the baffles automatically close to block outdoor insects and debris, preventing backflow of external airflow. When working, the baffles automatically open to ensure smooth airflow. A touch screen control panel 102 is installed at the bottom of the outer casing 1. Users can set the interval for automatic cleaning of the dust filter 4 (e.g., once a week) according to the usage environment through the control panel 102, or manually control each actuator. A mounting base 101 with mounting holes is also fitted on the outside of the outer casing 1 for fixing the entire unit to a wall or window opening. The control panel integrates a controller, providing a user-friendly interface and intuitive parameter settings. This allows users to easily check the equipment status, adjust cleaning parameters, or manually control each actuator at any time, improving the product's practicality and user experience.

[0025] like Figure 4 The inner casing 3 includes a support base 301. A front guardrail 305 is provided on the front side (i.e., the air intake side) of the support base 301 to prevent large, hard foreign objects from directly impacting the dustproof net 4 and damaging the fan's interior, thus protecting the fan's internal structure and enhancing safety. An air duct 302 is integrally connected to the rear end of the support base 301. The air duct is cylindrical, and motor-driven fan blades are installed inside. When the fan blades rotate, they generate negative pressure, drawing indoor air in through the front guardrail 305 and expelling it from the rear side of the outer casing 1 after passing through the air duct 302. A dustproof net 4 covers the front side of the support base 301. Located in front of the front guardrail 305, the dustproof net prevents dust from adhering to the front guardrail 305. The dustproof net 4 is made of dense polyester fiber (nylon or polyester mesh can also be used), with uniform honeycomb or grid-like openings and a mesh diameter of approximately 0.5-1 mm. This material is soft and elastic, with a surface treated with either hydrophilic or oleophobic agents. It effectively absorbs dust, lint, and oil particles from the air while also possessing excellent breathability and quick-drying properties. During washing, water can easily penetrate the mesh to remove dirt, and residual moisture evaporates quickly or is dried by the air-drying mechanism, preventing bacterial growth due to prolonged dampness.

[0026] To achieve automatic replacement and regeneration of the dustproof net 4, a roller 7 is provided on each of the left and right sides of the support base 301. The left end of the dustproof net 4 is wound around the left roller, and the right end is wound around the right roller, forming a reciprocating loop between the two rollers 7. Each roller 7 has a synchronous pulley fixed to its upper end, and a synchronous belt 702 is wound between the two pulleys. This synchronous belt 702 uses an "8" shaped cross-winding method, or the two rollers use different winding directions. A third motor is connected to the bottom of one of the rollers 7. When the third motor 701 drives one of the pulleys to rotate, the two rollers 7 rotate synchronously: one roller 7 winds up the dustproof net 4, while the other roller 7 unwinds synchronously. When the third motor 701 reverses, the winding and unwinding roles are reversed, and the dustproof net 4 moves in the opposite direction. Thus, only one third motor 701 is needed to achieve smooth winding and unwinding of the dustproof net 4 in both directions. The support base 301 has guide grooves 304 at its upper and lower ends, and the upper and lower edges of the dustproof net 4 are always embedded in the guide grooves 304 to prevent it from moving up and down during movement. Meanwhile, a tension roller 303 is provided at each of the left and right ends of the support base 301. Figure 5 As shown, the support base 301 is provided with a slide groove 306. The two ends of the tension roller are engaged with the slide groove 306 through the slide seat. The slide groove 306 is provided with a spring 307 that pushes the slide seat. The tension roller 303 is pressed against the back of the dustproof net 4 by the spring, so that the dustproof net 4 is always taut and flat in front of the air inlet, ensuring that all air passing through the air inlet must pass through the dustproof net 4.

[0027] like Figure 6 , Figure 7 , Figure 12 As shown, two sets of brushing mechanisms 5 and drying mechanisms 6 are set between the support base 301 and the roller 7, respectively located on the left and right sides of the air duct 302.

[0028] like Figure 8 As shown, the scrubbing mechanism 5 includes a water collection box 501 that is wider at the top and narrower at the bottom, through which a dustproof net 4 passes laterally. Two pairs of roller brushes 502 are symmetrically installed inside the water collection box 501, as shown in the image. Figure 10 As shown, two roller brushes 502 are respectively attached to the front and back of the dustproof net 4, and are driven to rotate relative to each other by a second motor 503 through a gear set. The second motor 503 is fixed to the upper end of the water collection box 501, and the rotation direction always causes the brush bristles to throw dirt from the surface of the dustproof net 4 away from the net surface. A spray pipe 504 is provided above (or on the side) of the roller brushes 502, and the spray pipe 504 has multiple small holes facing the dustproof net 4 and the roller brushes 502. Inside the outer casing 1, below the washing mechanism 5, there is a water box 2, as shown. Figure 9As shown, the interior of water box 2 is divided into a clean water tank 204 and a wastewater tank 201 by a partition. Both the clean water tank 204 and the wastewater tank 201 are drawer-type and can be pulled out. Clean water with added degreasing agent can be poured into the clean water tank 204, while the wastewater tank 201 is used to collect waste liquid after cleaning. A water collection port 202 is located on the upper surface of water box 2, corresponding to the position of the wastewater tank 201. A drain port 507 is located at the lowest point of the water collection box 501. The drain port 507 connects to the water collection port 202 or extends into the water collection port 202, and a sealing ring is provided between them. A miniature water pump 203 is also fixed to water box 2. The suction pipe of the water pump 203 extends into the bottom of the clean water tank 204, and the outlet pipe is connected to the spray pipe 504 via a flexible hose.

[0029] When a section of the dustproof net 4 becomes dirty and reaches the preset cleaning time, the third motor 701 starts, driving the dustproof net 4 to move to the right (or left). The dirty section first enters the water collection box 501. At this time, the water pump 203 starts, pumping the cleaning solution in the clean water tank 204 into the spray pipe 504 to rinse the dustproof net 4 and the roller brush 502; at the same time, the second motor 503 drives the roller brush 502 to rotate, vigorously scrubbing both sides of the dustproof net 4. The cleaned wastewater, under the action of gravity, collects along the inclined wall of the water collection box 501 to the drain outlet 507, and then flows into the wastewater tank 201 through the water collection outlet 202. In order to prevent the cleaned dustproof net 4 from carrying too much water into the winding state, a pair of inclined elastic scrapers 505 and a pair of absorbent cotton 506 are also installed in sequence in the water collection box 501. The scraper 505 is made of silicone, and its blades press against both sides of the dustproof mesh 4 at a certain angle. When the dustproof mesh 4 passes between the scraper 505, most of the residual water droplets are scraped off; then the absorbent cotton 506 adheres tightly to the surface of the dustproof mesh 4 to absorb the remaining water film. Figure 16 As shown, the scraper 505 and the absorbent cotton 506 are both fixed inside the water collection box 501 by the support rod 508, so that the scraper 505 and the absorbent cotton 506 always maintain good contact with the dustproof net 4.

[0030] After being treated by the scraper 505 and absorbent cotton 506, the dustproof net 4 is basically free of free water. A drying mechanism 6 is installed between the outlet of the brushing mechanism 5 and the right-side roller 7. Figure 13 , Figure 14 As shown, the drying mechanism 6 includes an air collecting groove 601 fixed to the inner wall of the air duct 302. The air collecting groove 601 is semi-circular, with its opening facing the outer edge of the fan blades. When the fan blades rotate at high speed, the high-speed airflow generated at the blade edges is captured and collected by the air collecting groove 601. The air collecting groove 601 is connected to the flow equalization pipe 603 via a flexible air duct 602. The flow equalization pipe 603 is vertically arranged on the right side of the dustproof net 4, and its length is greater than the width of the dustproof net 4. Figure 15As shown, a flow equalization plate 605 with multiple flow equalization holes is provided inside the flow equalization pipe 603 along its length. The interface of the air duct 602 is located on the rear side of the flow equalization plate 605, while the air outlet 604 is located on the front side of the flow equalization plate 605 and faces the dustproof net 4. The airflow generated by the fan blades enters the flow equalization pipe 603 through the air duct 602, is first evenly dispersed by the flow equalization plate 605, and then smoothly blown towards the dustproof net 4 from the multiple air outlets 604. Figure 3 As shown, a vent 104 corresponding to the position of the air outlet 604 is provided on the right side wall of the outer casing 1 to exhaust the moisture generated during the drying process. The air collection slot 601 utilizes the airflow generated by the fan blades themselves, eliminating the need for an additional fan. Since the surface moisture of the polyester fiber mesh has been largely scraped off and dried, mold will not occur after winding.

[0031] Positioning components 106 are also fixed at the upper and lower ends near the two rollers 7, such as... Figure 11 As shown, each positioning element 106 has a U-shaped positioning groove 107 at its end. The upper and lower edges of the dustproof net 4 pass through the positioning groove 107 to ensure that the layers are neatly stacked during the winding process, and that the edges do not curl up or deviate.

[0032] The actions of all the aforementioned actuators are coordinated by a controller built into the back of the control panel 102. The user can set the automatic cleaning cycle (e.g., every 7 days) through the control panel 102.

[0033] Users can set two automatic cleaning walking modes via the control screen 102 to adapt to different usage scenarios and dustproof net lengths.

[0034] The first mode is a reciprocating cycle operation: the controller employs an alternating direction walking strategy. For example, at the start of the first cleaning cycle, the controller drives the third motor 701 to rotate forward, causing the dust filter 4 to move one working zone length to the right. The dirty section that originally covered the air inlet is rolled up to the right, while the clean section unrolled from the left replaces it at the air inlet. During this movement, the brushing mechanism 5 and drying mechanism 6 on the right clean and dry the dirty section. At the start of the next cleaning cycle, the controller reverses the third motor 701, causing the dust filter 4 to move the same distance to the left. The cleaned section on the right is unrolled, while the originally clean section on the left (which has become dirty after a period of use) is rolled up to the left and cleaned and dried there. This process repeats, with the two sections of the dust filter 4 alternating between filtration and cleaning / regeneration. Each movement is exactly one working zone length, ensuring that the filter surface in front of the air inlet remains clean. This cycle repeats, with the two sections alternating between filtration and cleaning processes, achieving efficient and regular self-cleaning. This model is suitable for situations where the length of the dustproof net is limited and the overall structure is more compact. For example... The second mode involves multiple unidirectional movements followed by reversal: When the total length of the dustproof net 4 is much greater than the width of the working area, the controller adopts a "unidirectional cumulative movement, reversal after reaching the limit" strategy. The user can set the distance of each cleaning movement (usually equal to the working area width) and the maximum number of unidirectional movements via the control panel 102. For example, setting each movement to move the working area width and then moving 5 times in the same direction. During the first cleaning, the controller drives the dustproof net 4 to move one working area width to the right, and the dirty section is rolled up and cleaned. During the second cleaning, it continues to move the same distance to the right. After moving to the right 5 times consecutively, a clean section five times the length of the working area has been unrolled on the left side of the dustproof net 4, while five dirty sections have accumulated on the right roller. At this point, the controller records that the maximum number of movements has been reached. When the next cleaning cycle arrives, the controller automatically switches direction, driving the dustproof net 4 to move to the left. During the leftward movement, the earliest rolled-up dirty section (already cleaned and dried) on the right roller is unrolled, while the clean section on the left (now dirty) is rolled up and cleaned. During the leftward movement, the same distance is moved each time until the area returns to near the initial position, then the direction is switched again. This mode makes full use of the longer dust filter reserve, reducing the frequency of cleaning, while the distance moved each time is still no less than the length of the outer casing (i.e., the width of the working area), ensuring that the section of dust filter currently covering the air inlet is completely replaced, and there is no mixing of new and old filter surfaces.

[0035] Regardless of the logic employed, when the controller initiates the cleaning program, it simultaneously controls the third motor 701 (low-speed traction), the second motor 503 (driving the roller brush), and the water pump 203 (spraying) to work in coordination. After the dust screen 4 has traveled the predetermined distance, spraying and brushing will continue for a short period to clean the interior of the mechanism, and then stop. The drying mechanism 6 utilizes the system's own airflow to dry the brushed screen section throughout the process. The entire cleaning process is completed automatically without manual intervention and does not affect the normal ventilation operation of the exhaust fan.

[0036] During non-cleaning periods, users can pull out the sewage tank 201 or the clean water tank 204 at any time, empty the waste liquid in the sewage tank 201, and add clean cleaning solution to the clean water tank 204. The whole process does not require turning off the exhaust fan power and does not affect the normal ventilation of the fan blades, truly achieving non-stop maintenance.

[0037] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An exhaust fan, comprising an inner casing, the inner casing including a support base, a front guardrail at the air inlet of the support base, an air duct connected to the rear end of the support base, and fan blades disposed within the air duct, characterized in that: The front end of the support base is equipped with a dustproof net to block the air inlet. Roller rollers are provided on both sides of the air duct. The two ends of the dustproof net are wound around the rollers. The dustproof net can be wound back and forth between the two rollers. Between the support base and the rollers, there is a brushing mechanism for cleaning the dustproof net and a drying mechanism for drying the dustproof net. An outer casing is fitted on the outside of the inner casing. A control panel is provided at the bottom of the outer casing.

2. An exhaust fan as described in claim 1, characterized in that: The rear opening of the outer casing is provided with a rear grille, which includes evenly spaced baffles. A first motor is provided inside the outer casing to drive the baffles to rotate synchronously.

3. An exhaust fan as described in claim 1, characterized in that: The upper and lower ends of the support base are provided with guide grooves that cooperate with the ends of the dustproof net. The two ends of the support base are provided with tension rollers that support the dustproof net. The upper ends of the two rollers are connected by a synchronous belt. A third motor that drives the rollers to rotate is provided inside the outer casing.

4. An exhaust fan as described in claim 1, characterized in that: The washing mechanism includes a water collection box that is wider at the top and narrower at the bottom. The water box is located inside the outer casing, and it contains a sewage tank and a clean water tank. The upper end of the water box has a water inlet that communicates with the sewage tank, and the lower end of the water box has a drain outlet that connects with the water inlet. A dustproof net passes horizontally through the water collection box. The water collection box contains a roller brush that washes both sides of the dustproof net. The roller brush is driven by a second motor. A spray pipe is located above the roller brush, and a water pump is located at the upper end of the water box. The water pump draws water from the clean water tank into the spray pipe.

5. An exhaust fan as described in claim 4, characterized in that: The water collection box is equipped with an inclined scraper. The scraper is elastic and presses against both sides of the dustproof net. Water-absorbing cotton is provided behind the scraper. The water-absorbing cotton and the scraper are fixed to the water collection box by a support rod.

6. An exhaust fan as described in claim 1, characterized in that: The air drying mechanism includes an air collecting groove fixed on the inner wall of the air duct. The air collecting groove is connected to a flow equalization pipe through an air duct. The flow equalization pipe is located on the outside of the air duct. An air outlet is provided on the side wall of the flow equalization pipe, facing the dustproof net. An air window corresponding to the position of the air outlet is provided on the side wall of the outer casing.

7. An exhaust fan as described in claim 6, characterized in that: The air collecting groove has a semi-circular ring structure, with the opening of the air collecting groove facing the fan blade, and both ends of the air collecting groove are closed structures.

8. An exhaust fan as described in claim 6, characterized in that: The flow equalization pipe is vertically located on one side of the dustproof net, and the length of the flow equalization pipe is not less than the width of the dustproof net. A perforated flow equalization plate is vertically provided in the middle of the flow equalization pipe, and the air duct and air outlet are located on both sides of the flow equalization plate.

9. An exhaust fan as described in claim 6, characterized in that: A positioning component that connects to the outer casing is provided near the roller. The end of the positioning component is provided with a positioning groove to guide the upper or lower end of the dustproof net.

10. An exhaust fan as described in claim 6, characterized in that: The outer side of the outer casing is fitted with a mounting base with mounting holes.

Images