Backdraft prevention air duct assembly

Abstract

The application relates to the field of exhaust equipment, in particular to a backflow prevention exhaust pipe assembly, which comprises an exhaust fan, a tapered joint pipe, an exhaust hose and a check valve which are sequentially and sealingly connected, the tapered joint pipe is provided with a large-diameter end and a small-diameter end, the large-diameter end is sealingly connected with the exhaust hose, the small-diameter end is sealingly connected with an air outlet end of the exhaust fan, the tapered joint pipe is downwardly and obliquely arranged towards the exhaust hose, a spiral oil guide groove is arranged on the inner wall of the tapered joint pipe, and the spiral oil guide groove guides oil stains to flow to the exhaust hose. The backflow prevention exhaust pipe assembly can effectively prevent oil fume in a main oil fume exhaust pipe from flowing back, improves the convenience of oil fume pipe cleaning, prevents excessive oil stains from accumulating in the exhaust hard pipe of the exhaust pipe assembly or the exhaust fan, prevents the problem that oil stain cleaning is relatively difficult, improves the maintainability of the whole exhaust pipe assembly, and guarantees efficient and stable operation of the exhaust system.

Description

Technical Field

[0001] This application relates to the field of ventilation equipment, and in particular to an anti-backflow ventilation duct assembly. Background Technology

[0002] In the field of ventilation systems, especially in the kitchen fume extraction systems of commercial buildings, ventilation technology plays a crucial role. With the acceleration of urbanization, commercial buildings such as shopping malls, hotels, and restaurants are constantly emerging and expanding in scale, and people's requirements for indoor environmental quality are becoming increasingly stringent. An efficient and stable ventilation system can not only promptly and effectively remove the large amounts of oil fumes generated during kitchen cooking, reducing indoor odor concentration and air pollution, but also prevent the accumulation of oil fumes on kitchen equipment and building structures, reducing the probability of damage to kitchen equipment, extending its service life, and thus improving the economic efficiency and stability of commercial operations. Currently, exhaust duct components on the market typically use conventional methods to achieve ventilation. A typical exhaust duct component includes an exhaust fan, an exhaust duct, and a check valve. After the exhaust fan is started, the oil fumes pass through the exhaust fan and exhaust duct in sequence, and then through the check valve to be discharged outdoors. Some exhaust ducts are composed of both flexible and rigid pipes, with flexible pipes facilitating pipe penetration through walls and handling applications with height differences. The check valve employs a simple shaft and spring mechanical structure. When there is forward exhaust, the valve opens under the action of wind force; after the exhaust stops, the valve automatically closes due to the spring's restoring force, preventing backflow of fumes and odors. When long-distance fumes transport is required, the exhaust pipes are connected and transitioned through welding, flanges, or other means to ensure smooth airflow through pipes of different diameters. These methods, to a certain extent, meet the basic requirements of the exhaust system. However, existing exhaust pipe components have significant drawbacks. After long-term use, grease easily accumulates inside the exhaust pipes and is difficult to clean, especially since rigid pipes and exhaust fans are usually made of rigid materials, making cleaning their inner walls troublesome. Replacing rigid pipes is costly, and fumes easily clog the check valve, causing it to malfunction. Utility Model Content

[0003] In order to improve the convenience of cleaning kitchen exhaust ducts and prevent excessive oil from accumulating in the exhaust pipe or exhaust fan of the exhaust duct assembly, which would make oil cleaning difficult, this application provides an anti-backflow exhaust duct assembly.

[0004] This application provides an anti-backflow exhaust duct assembly, comprising an exhaust fan, a tapered connector pipe, a check valve, and an exhaust hose connected in sequence and sealed. The tapered connector pipe has a large-diameter end and a small-diameter end. The large-diameter end of the tapered connector pipe is sealed to the exhaust hose, and the small-diameter end of the tapered connector pipe is sealed to the exhaust fan outlet. The exhaust hose is telescopic, and the check valve uses the telescopic characteristic of the exhaust hose to dynamically block the exhaust hose. The inner wall of the tapered connector pipe is provided with a spiral oil guide groove, which guides oil to flow to the exhaust hose. By adopting the above technical solution, the large-diameter end of the tapered connector pipe is sealed to the exhaust hose, and the small-diameter end is sealed to the exhaust fan outlet, while the inner wall is provided with a spiral oil guide groove. During the operation of the exhaust duct assembly, when oil fumes enter the tapered connector pipe from the exhaust fan and are then discharged through the exhaust hose, some oil will adhere to the inner wall of the tapered connector pipe. Due to the tapered design of the tapered connector, oil tends to flow downwards under gravity. The spiral oil guide groove further guides the oil along the groove, effectively directing it to the exhaust hose. This reduces oil accumulation within the tapered connector, lowers the difficulty of cleaning its interior, and prevents excessive oil buildup from affecting the normal operation and lifespan of the exhaust duct assembly. Compared to cleaning rigid pipes, cleaning or replacing the exhaust hose is relatively cheaper. The hose is flexible, requiring only periodic disconnection of either end to empty the accumulated oil, effectively preventing hardened oil buildup and improving the overall maintainability of the exhaust duct assembly. It also effectively prevents backflow of fumes and odors, ensuring the efficient and stable operation of the exhaust system. Preferably, the tapered angle of the inner wall of the tapered connector is between 1:5 and 1:8. By adopting the above technical solution, the taper range of the inner wall of the tapered connector pipe is set to 1:5 - 1:8. Within this taper range, the diameter change of the tapered connector pipe can effectively guide the oil sludge flow to the exhaust hose and also adapt to the flow characteristics of oil fumes. When oil fumes flow from the exhaust hose into the tapered connector pipe, the flow velocity of the oil fumes gradually increases and the pressure gradually decreases due to the gradual reduction in pipe diameter. Preferably, the check valve includes a conical valve plate and a conical sealing plate. The conical valve plate has a large-diameter end and a small-diameter end. The large-diameter end of the conical valve plate is connected to the inner wall of the tapered connector pipe. The small-diameter end of the conical valve plate extends into the exhaust hose and is suspended inside the exhaust hose. The conical sealing plate has a large-diameter end and a small-diameter end. The large-diameter end of the conical sealing plate is connected to the exhaust hose. The small-diameter end of the conical sealing plate faces the small-diameter end of the conical valve plate. The conical sealing plate is movably and tightly attached to the outer wall of the conical valve plate to block the exhaust channel of the exhaust hose.By adopting the above technical solution, the large-diameter end of the conical valve plate is firmly connected to the inner wall of the tapered connector pipe, while the small-diameter end extends into the exhaust hose and is suspended in the air. This design causes the exhaust hose to deform outwards and towards the conical sealing plate during the exhaust process, exhibiting deformation in both the axial and radial directions. The conical sealing plate is driven to move towards its larger diameter end, while its smaller diameter end rotates outwards around the larger diameter end, causing the smaller diameter end of the conical sealing plate to open and allowing the fumes to be discharged smoothly. When fumes want to enter through the larger diameter end of the conical sealing plate, the exhaust hose deforms towards the tapered connector pipe. Therefore, the conical sealing plate also moves towards the tapered connector pipe, resulting in a tight seal between the conical sealing plate and the outer wall of the conical valve plate. This effectively reduces turbulence and eddies in the exhaust duct, lowers exhaust resistance, and improves the smoothness and efficiency of exhaust, allowing fumes to be discharged outdoors more quickly and thoroughly. It also prevents the accumulation of fumes from clogging the exhaust hose and causing the check valve to fail to effectively seal it. Preferably, the conical sealing plate has an annular sealing ring at its small-diameter end, the shape of which is adapted to the outer wall of the conical valve plate. By adopting the above technical solution, the annular sealing ring at the edge of the conical valve plate enhances the sealing performance of the check valve and effectively prevents backflow of oil fumes. Preferably, both the outer and inner walls of the exhaust hose are provided with spiral air-guiding corrugations. By adopting the above technical solution, the spiral air-guiding corrugations on both the outer and inner walls allow the airflow to change its direction and speed when it flows through the outer wall, creating a spiral flow pattern. This spiral airflow better conforms to the outer wall of the outer pipe, reducing separation and vortex generation between the airflow and the outer wall, thus guiding the airflow through stably, reducing vibration transmission, lowering noise, and providing good deformation force. Preferably, the tapered connector is a metal pipe. By adopting the above technical solution, the tapered connector is made of metal, which has good strength and rigidity, can withstand certain pressure and external forces, and is not easily deformed or damaged. During operation, the exhaust duct assembly is subjected to the impact of oil fumes and the pressure of airflow. The metal tapered joint pipe maintains a stable structure, ensuring the normal operation of the exhaust duct assembly. At the same time, metal generally has good corrosion resistance, resisting the erosion of chemical components in oil fumes and extending the service life of the tapered joint pipe.

[0005] Preferably, the annular sealing ring is a silicone sealing ring. By adopting the above technical solution, the sealing performance can be improved, and oil stains are less likely to accumulate. Preferably, the wall thickness of the tapered connector tube is uniform. By adopting the above technical solution, a uniform wall thickness ensures that the structural strength of each part of the tapered connector tube is uniform, avoiding deformation or damage in some weak parts due to uneven wall thickness, thus improving the overall reliability and service life of the tapered connector tube.

[0006] In summary, this application includes at least one of the following beneficial technical effects: 1. The inner wall of the tapered joint pipe is equipped with a spiral oil guide groove. Under the guidance of gravity and the spiral oil guide groove, the oil will flow along the spiral oil guide groove to the exhaust hose, effectively preventing the backflow of oil fumes in the exhaust duct, thereby reducing the accumulation of oil in the exhaust fan and rigid pipe, and effectively solving the problem of oil fumes accumulating in the exhaust pipe and being difficult to clean in the existing technology. 2. The check valve includes a conical valve plate and a conical sealing plate. This specially structured check valve utilizes the deformation and expansion characteristics of the exhaust hose to flexibly block the exhaust passage of the exhaust hose, effectively preventing the accumulation of oil and dirt that could clog the check valve. 3. A tapered connector is used to connect the exhaust fan and the exhaust hose. The tapered connector has a large diameter end and a small diameter end. The large diameter end is sealed to the exhaust hose, and the small diameter end is sealed to the air inlet of the exhaust fan. This structural design ensures that the fumes can flow smoothly in pipes of different diameters. Attached Figure Description

[0007] Figure 1 This is an exploded view of an anti-backflow exhaust duct assembly according to this application; Figure 2 This is a structural diagram of an anti-backflow exhaust duct assembly according to this application; Figure 3 This is a cross-sectional view of the exhaust state of an anti-backflow exhaust duct assembly according to this application; Figure 4 This is a cross-sectional view of an anti-backflow exhaust duct assembly in its normally closed state, as described in this application.

[0008] Explanation of reference numerals in the attached drawings: 1. Exhaust fan; 2. Retractable connector pipe; 3. Exhaust hose; 4. Check valve; 5. Connector pipe; 21. Spiral oil guide groove; 31. Spiral air guide corrugation; 41. Conical valve plate; 42. Conical sealing plate; 411. Connector; 421. Annular sealing ring. Detailed Implementation

[0009] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0010] This application provides an anti-backflow exhaust duct assembly, referring to... Figure 1 and Figure 2The system includes a fan 1, a tapered connector 2, a flexible exhaust hose 3, a check valve 4, and a connector 5 connected in sequence. After the fan 1 is started, the fumes pass through the fan 1 and the tapered connector 2 in sequence, and then through the flexible exhaust hose 3 and the connector 5 to be discharged outdoors. In this embodiment, the two ends of the tapered connector 2 are connected to the fan 1 and the flexible exhaust hose 3, respectively. The flexible exhaust hose 3 and the connector 5 are sealed together. The connector 5 is used for installation on external buildings. In other embodiments, a rigid exhaust pipe can be added between the fan 1 and the tapered connector 2 to guide the oil in the rigid exhaust pipe to the flexible exhaust hose 3.

[0011] Specifically, the tapered connector pipe 2 is integrally formed from the pipe body, large-diameter end, and small-diameter end, ensuring the integrity and sealing of the tapered connector pipe 2 and reducing the risk of leakage at the connection point. The inner wall surface of the pipe is smooth, and the pipe body is tapered, with an inner wall taper ranging from 1:5 to 1:8. This taper design is beneficial for the flow and concentration of oil fumes. The pipe body is made of metal, which has good strength and durability and can withstand certain pressure and temperature changes. Of course, some high-strength plastic materials can also be used to replace metal, as long as the strength and temperature resistance requirements are met. The pipe body wall thickness is uniform, which ensures the stability and uniformity of its structure.

[0012] Specifically, the inner wall of the pipe is integrally formed with a spiral oil guide groove 21, which is directly formed on the inner wall of the pipe through machining. The function of the spiral oil guide groove 21 is to guide the oil sludge to flow along the groove, and its shape can be a continuous spiral. The larger diameter end is used for a sealed connection with the exhaust hose 3. The sealing connection can be achieved using sealing rings, sealant, etc., to ensure that there is no oil fume leakage at the connection. The smaller diameter end is used for a sealed connection with the air inlet end of the exhaust fan 1, and the same sealing measures are used to ensure the airtightness of the connection.

[0013] Specifically, in this embodiment, both the inner and outer walls of the exhaust hose 3 are provided with spiral air-guiding corrugations 31. The spiral air-guiding corrugations 31 can enhance the flexibility and deformation resistance of the outer tube, and at the same time help guide the airflow to achieve the effect of reducing noise.

[0014] Reference Figure 3 and Figure 4Specifically, the check valve 4 in this embodiment includes a conical valve plate 41 and a conical sealing plate 42. The conical valve plate 41 is surrounded by a large-diameter end and a small-diameter end, and the conical sealing plate 42 is surrounded by a large-diameter end and a small-diameter end. The large-diameter end of the conical valve plate 41 is connected to the inner wall of the tapered connector pipe 2 through a connector 411. The small-diameter end of the conical valve plate 41 extends into the interior of the exhaust hose 3 and is suspended in the middle of the exhaust hose 3. The large-diameter end of the conical sealing plate 42 is connected to the exhaust hose 3, and the small-diameter end of the conical sealing plate 42 faces the small-diameter end of the conical valve plate 41. The conical sealing plate 42 is movably and tightly attached to the outer wall of the conical valve plate 41 to block the exhaust channel of the exhaust hose 3. The conical sealing plate 42 has a silicone annular sealing ring 421 at its small-diameter end. The shape of the annular sealing ring 421 is adapted to the outer wall of the conical valve plate 41, which can improve the sealing performance between the conical sealing plate 42 and the conical valve plate 41. The conical sealing plate 42 is made of silicone.

[0015] The smoke extraction principle of the exhaust duct assembly is as follows: When the exhaust fan 1 is started, a negative pressure is formed inside the exhaust duct assembly under the action of the exhaust fan 1. The air pressure at the indoor oil fume location is greater than the air pressure inside the exhaust duct assembly. Under the action of the pressure difference, the oil fumes are drawn into the exhaust duct assembly. When the range hood is turned on, it generates a strong suction force, causing the oil fumes and air in the kitchen to form an airflow, which flows along the tapered connector 2 to the exhaust hose 3. The airflow first impacts the conical valve plate 41. Since the large-diameter end of the conical valve plate 41 is fixed to the inner wall of the tapered connector 2 through the connector 411, and the small-diameter end extends into the exhaust hose 3 and is suspended, the airflow will flow smoothly along the conical surface of the conical valve plate 41 to the exhaust hose 3.

[0016] As the airflow continues, the conical sealing plate 42, which was originally tightly attached to the outer wall of the conical valve plate 41, will be blown open under the pressure of the airflow. Because the large-diameter end of the conical sealing plate 42 is connected to the exhaust hose 3, and the small-diameter end faces the small-diameter end of the conical valve plate 41, the airflow can overcome the adhesion between the sealing plate and the valve plate, causing the sealing plate to rotate around its large-diameter end at a certain angle, thereby opening the exhaust channel and allowing the fumes to be smoothly discharged outdoors through the exhaust hose 3.

[0017] When the range hood stops working, the airflow in the exhaust hose 3 gradually stops, and the pressure inside and outside the exhaust system tends to balance. The conical sealing plate 42 will gradually return to its original position, tightly attached to the outer wall of the conical valve plate 41. Since the small diameter end of the conical sealing plate 42 faces the small diameter end of the conical valve plate 41, and its shape is adapted to the conical valve plate 41, when the sealing plate is tightly attached to the outer wall of the valve plate, it can completely block the exhaust passage of the exhaust hose 3, preventing the backflow of fumes, odors, and other gases in the public flue back into the room, thus playing a backflow prevention role.

[0018] The implementation principle of this embodiment is as follows: When the exhaust fan 1 is started, the fumes pass sequentially through the exhaust fan 1 and the tapered connector pipe 2, and are then discharged outdoors via the exhaust hose 3. During this process, the spiral oil guide groove 21 of the tapered connector pipe 2 guides the oil to flow into the exhaust hose 3, facilitating centralized cleaning and reducing the accumulation of oil in the tapered connector pipe 2 and the exhaust fan 1, thus lowering the difficulty and cost of cleaning. Simultaneously, the conical valve plate 41 and conical sealing plate 42 of the check valve 4 effectively prevent backflow of outdoor air, ensuring indoor air quality. This structural design improves the practicality and reliability of the exhaust duct assembly.

[0019] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A backflow prevention exhaust duct assembly, characterized in that, The device includes a blower (1), a tapered connector pipe (2), a check valve (4), and a blower hose (3) connected in sequence and sealed. The tapered connector pipe (2) is provided with a large-diameter end and a small-diameter end. The large-diameter end of the tapered connector pipe (2) is sealed to the blower hose (3), and the small-diameter end of the tapered connector pipe (2) is sealed to the air outlet end of the blower (1). The blower hose (3) is telescopic. The check valve (4) is used to block the pipe of the blower hose (3) by means of the telescopic characteristics of the blower hose (3). The inner wall of the tapered connector pipe (2) is provided with a spiral oil guide groove (21), which guides the oil to flow to the blower hose (3).

2. The anti-backflow exhaust duct assembly according to claim 1, characterized in that, The tapered inner wall of the tapered joint pipe (2) has a taper range of 1:5 - 1:

8.

3. The anti-backflow exhaust duct assembly according to claim 1, characterized in that, The check valve (4) includes a conical valve plate (41) and a conical sealing plate (42). The conical valve plate (41) is surrounded by a large-diameter end and a small-diameter end. The large-diameter end of the conical valve plate (41) is connected to the inner wall of the tapered connector pipe (2) through a connector (411). The small-diameter end of the conical valve plate (41) extends into the interior of the exhaust hose (3) and is suspended inside the exhaust hose (3). The conical sealing plate (42) is surrounded by a large-diameter end and a small-diameter end. The large-diameter end of the conical sealing plate (42) is connected to the exhaust hose (3). The small-diameter end of the conical sealing plate (42) faces the small-diameter end of the conical valve plate (41). The conical sealing plate (42) is movably and tightly attached to the outer wall of the conical valve plate (41) to block the exhaust channel of the exhaust hose (3).

4. The anti-backflow exhaust duct assembly according to claim 3, characterized in that, The conical sealing plate (42) has an annular sealing ring (421) at its small diameter end, and the shape of the annular sealing ring (421) is adapted to the outer wall of the conical valve plate (41).

5. The anti-backflow exhaust duct assembly according to claim 4, characterized in that, The outer and inner walls of the exhaust hose (3) are both provided with spiral air guiding corrugations (31).

6. The anti-backflow exhaust duct assembly according to claim 1, characterized in that, The tapered connector tube (2) is a metal tube.

7. The anti-backflow exhaust duct assembly according to claim 4, characterized in that, The annular sealing ring is a silicone sealing ring.

8. The anti-backflow exhaust duct assembly according to claim 1, characterized in that, The tapered joint pipe (2) has a uniform wall thickness.

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