A backflow prevention duct structure for range hoods

Abstract

This utility model discloses an anti-backflow duct structure for a range hood, relating to the field of range hood duct technology. It includes a double-petal check valve, a connecting seat, and a duckbill valve connected in sequence. The duckbill valve body is inserted into the wall-mounted flue. The internal channels of these three components form an airflow channel. The double-petal check valve is connected to the exhaust end of the range hood via a smoke supply pipe. The connecting seat has a base with a snap-fit ​​ring. The air inlet end of the duckbill valve forms a double mounting groove through double L-shaped connecting rings, which are fitted and assembled with the snap-fit ​​rings. The inner wall of the smoke supply pipe has a tapered, gradually changing guide ring. The outlet end of the duckbill valve has a U-shaped groove and a gradually decreasing thickness elastic deformation section. The outer surface of the deformation section has strip-shaped reinforcing ribs, and the bottom end of the groove has an annular reinforcing rib. The inner wall of the air inlet end of the duckbill valve has an axial guide rib. When the range hood is working, the airflow pushes open the two components to exhaust smoke. When the range hood stops, the double-petal valve initially closes, and the duckbill valve self-tightens to seal, achieving double anti-backflow and featuring stable sealing, low noise, and high durability.

Description

Technical Field

[0001] This utility model relates to the field of range hood technology, and in particular to an anti-backflow duct structure for range hoods. Background Technology

[0002] In the flue system of a range hood, the double-disc check valve is the mainstream anti-backflow component. It achieves sealing by opening and closing two semi-circular valve discs: when the smoke is discharged in the forward direction, the airflow pushes the valve discs to open; when the machine stops, the valve discs close by their own weight or spring force, forming a seal against the valve seat. The two ends of the housing are connected to the range hood's smoke supply pipe and the common flue, respectively. However, in actual use, the double-disc check valve has defects in the negative pressure environment of a public flue: At night or during off-peak hours, the airflow in the upper-level flue creates a downward suction force. This negative pressure continuously acts on the upper surface of the valve disc, counteracting the closing force of the valve disc. This counteracting force causes the valve disc to vibrate in a "closing and opening" manner—the closing force attempts to press the valve disc against the valve seat, while the negative pressure continuously pulls the valve disc away. This repeated mechanical impact not only generates significant noise but also creates a momentary channel in the opening and closing gap.

[0003] At this time, residual fumes or odors in the upper-level user's flue will be drawn into the lower level through these dynamic gaps by negative pressure, causing backflow. This chain reaction of "vibration-noise-backflow" is rooted in the fact that the closing force of the traditional valve disc cannot coordinate with the negative pressure suction, resulting in an unstable sealing state. Utility Model Content

[0004] To address the aforementioned problems, the purpose of this utility model is to provide an anti-backflow duct structure for range hoods, thereby solving the problem of backflow of fumes caused by the instantaneous formation of a channel by negative pressure pulling the valve disc in the prior art.

[0005] The technical solution of this utility model is as follows: A backflow prevention duct structure for a range hood includes a double-leaf check valve, a connecting seat, and a duckbill valve connected in sequence. The main body of the duckbill valve is inserted into the flue inside the wall. The internal channels of the double-leaf check valve, the connecting seat, and the duckbill valve together form an airflow channel connected to the flue.

[0006] The air inlet of the duckbill valve and the air outlet of the double-leaf check valve are connected to each other via a connecting seat. The air inlet of the double-leaf check valve is connected to the exhaust end of the range hood via a smoke supply pipe.

[0007] When the range hood is working, the forward airflow sequentially pushes open the valve plate of the double-leaf check valve and the elastic deformation section of the duckbill valve, quickly discharging into the flue. When the range hood stops, the valve plate of the double-leaf check valve initially closes under its own weight and the slight pressure of the flue, while the elastic deformation section of the duckbill valve forms a "self-tightening seal" due to its own elasticity. Unlike the double-leaf check valve plate, which is easily pulled by negative pressure, the elastic closing force of the duckbill valve is in the same direction as the negative pressure suction of the flue, which further presses the deformation section to fit tightly, eliminating dynamic gaps and doubly blocking the backflow of oil fumes in the flue into the kitchen.

[0008] Furthermore, the connecting seat includes a sheet-like base with a through-hole in the center, and the edge of the through-hole extends axially to form a snap ring.

[0009] A first L-shaped connecting ring is wound around the outer ring wall of the air inlet end of the duckbill valve. The first L-shaped connecting ring and the outer ring wall of the duckbill valve form a first mounting groove facing the opening of the base. The snap-fit ​​ring is adapted to snap into the first mounting groove.

[0010] A second L-shaped connecting ring is wound around the inner ring wall of the air inlet end of the duckbill valve. The second L-shaped connecting ring and the inner ring wall of the duckbill valve form a second mounting groove facing the opening of the double-leaf check valve. The air outlet end of the double-leaf check valve is adapted to be inserted into the second mounting groove.

[0011] The double L-shaped connecting rings of the duckbill valve form double mounting grooves. During assembly, the snap ring is first inserted into the first mounting groove. After the clamp is fitted around the outer circumference of the first L-shaped connecting ring, the duckbill valve and the connecting seat are assembled. Then, the air outlet end of the double-disc check valve is snapped into the second mounting groove, and the double-disc check valve is simultaneously inserted into the snap ring of the connecting seat to complete the assembly.

[0012] Furthermore, a tapered, gradually decreasing guide ring is provided on the inner wall of the flue section near the air inlet side of the double-disc check valve. The inner diameter of the gradually decreasing guide ring gradually decreases from the inlet end of the flue towards the double-disc check valve along the airflow direction, and the minimum inner diameter of the gradually decreasing guide ring is 8% to 15% smaller than the air inlet diameter of the double-disc check valve. There is a gap between the end of the gradually decreasing guide ring and the air inlet of the double-disc check valve. This design allows the airflow to form an "acceleration effect" at the end of the guide ring, quickly impacting the valve plate of the double-disc check valve and shortening the opening / closing response time of the valve plate of the double-disc check valve.

[0013] Furthermore, the outer wall of the outlet end of the duckbill valve is provided with a ring-shaped groove. The cross-section of the groove is U-shaped. The side of the groove near the outlet forms an elastic deformation section with a gradually decreasing thickness. The gradually decreasing thickness design makes the end of the deformation section more elastic and the root stronger. When a downward negative pressure suction force occurs in the flue, the negative pressure will act on the outside of the deformation section, pressing the deformation section inward and making the sealing surface fit more tightly.

[0014] Furthermore, at least four axially spaced strip-shaped reinforcing ribs are provided on the outer surface of the outlet end of the elastic deformation section; the extension direction of the strip-shaped reinforcing ribs is consistent with the airflow conduction direction of the duckbill valve, and the strip-shaped reinforcing ribs extend directly from the opening edge of the outlet end of the elastic deformation section along the outer surface to the root of the groove wall near the outlet side of the groove, forming "complete support from the end to the groove" - ​​in the high-pressure negative pressure scenario of high-rise flue, the strip-shaped reinforcing ribs can disperse the negative pressure and ensure that the deformation section closes uniformly in the width direction.

[0015] Furthermore, the bottom of the groove of the duckbill valve is provided with a ring-shaped reinforcing rib. The cross-section of the reinforcing rib is semi-circular, and its height is 1 / 3 to 1 / 2 of the depth of the U-shaped groove. The reinforcing rib extends circumferentially along the bottom of the groove, and its two ends are smoothly transitioned to the two side walls of the groove through arc surfaces to avoid stress concentration caused by right-angle transitions. Under the continuous action of the negative pressure of the flue for a long time, the bottom of the groove is a concentrated area of ​​deformation stress and is prone to cracks due to long-term deformation. The ring-shaped reinforcing rib can disperse the deformation stress to the two side walls of the groove, thereby improving the bending fatigue resistance of the bottom of the groove and maintaining a stable elastic closing force. This avoids sealing failure under negative pressure due to fatigue deformation, forming a synergistic effect of "long-term durability + stable sealing" with the double-disc check valve.

[0016] Furthermore, the inner wall of the air inlet end of the duckbill valve is provided with at least four axial guide ribs. The guide ribs are integrally formed with the inner wall of the duckbill valve. The guide ribs extend from the edge of the air inlet into the valve body. The length of the guide ribs is 1 / 3 of the total length of the duckbill valve. The cross-section is an isosceles triangle and is evenly distributed along the circumference. The triangular cross-section can make the airflow smoothly split along the rib surface and avoid the generation of eddies. The guide ribs can divide the airflow entering the duckbill valve into a uniform airflow bundle and guide the airflow to flow along the inner wall of the valve body, reducing the generation of eddies. At the same time, it can avoid airflow pressure fluctuations caused by eddies, indirectly ensuring the stability of the opening and closing of the double-lobe check valve plate and maintaining the smoke exhaust and sealing performance of the overall air duct.

[0017] The beneficial effects of this utility model are as follows: 1. This utility model forms a double backflow prevention protection through the combination structure of a double-disc check valve and a duckbill valve. When the air is in the forward direction, the airflow can smoothly push open the valve plate of the double-disc check valve and the elastic deformation section of the duckbill valve to ensure the smoke exhaust efficiency. When the machine is stopped, the valve plate of the double-disc check valve will initially close due to its own weight and the slight pressure of the flue. The elastic deformation section of the duckbill valve will form a self-tightening seal due to its own elasticity. Moreover, the elastic closing force of the duckbill valve is in the same direction as the negative pressure suction force of the flue, which can further press the deformation section to achieve a tight fit. There is no mechanical vibration of "closing and closing", which reduces the generation of dynamic gaps and ensures the backflow prevention effect of oil fumes.

[0018] 2. In this utility model, the groove of the duckbill valve provides deformation guidance space for the elastic deformation section. The gradually narrowing thickness design makes the end of the deformation section highly elastic and easy to open and close. The root has high strength and strong fracture resistance. When a downward negative pressure suction force occurs in the flue, the negative pressure can act on the outside of the deformation section, pressing the deformation section inward, further improving the sealing surface fit and ensuring sealing. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] Figure 2 This is a schematic diagram of the disassembled structure of this utility model.

[0021] Figure 3 This is a cross-sectional view of the present invention in its assembled state.

[0022] Figure 4 This is a schematic diagram of the duckbill valve structure of this utility model.

[0023] Reference numerals in the attached diagram: 1. Double-disc check valve; 2. Connecting seat; 2-1. Base; 2-2. Snap-fit ​​ring; 3. Duckbill valve; 3-1. First L-shaped connecting ring; 3-2. Second L-shaped connecting ring; 3-3. Groove; 3-3.1. Reinforcing rib; 3-4. Elastic deformation section; 3-4.1. Strip-shaped reinforcing rib; 3-5. Flow guide rib; 4. Gradient guide ring. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0025] like Figures 1 to 4 As shown, an anti-backflow duct structure for a range hood includes a double-leaf check valve 1, a connecting seat 2, and a duckbill valve 3 connected in sequence. The main body of the duckbill valve 3 is inserted into the flue inside the wall. The internal channels of the double-leaf check valve 1, the connecting seat 2, and the duckbill valve 3 together form an airflow channel connected to the flue.

[0026] The air inlet of the duckbill valve 3 and the air outlet of the double-leaf check valve 1 are connected to each other through the connecting seat 2. The air inlet of the double-leaf check valve 1 is connected to the exhaust end of the range hood through the smoke supply pipe.

[0027] When the range hood is working, the forward airflow sequentially pushes open the valve plate of the double-leaf check valve 1 and the elastic deformation section 3-4 of the duckbill valve 3, and quickly discharges into the flue. When the range hood is stopped, the valve plate of the double-leaf check valve 1 initially closes under its own weight and the slight pressure of the flue, while the duckbill valve 3 relies on its own elasticity to form a "self-tightening seal" - unlike the valve plate of the double-leaf check valve 1 which is easily pulled by negative pressure, the elastic closing force of the duckbill valve 3 is in the same direction as the negative pressure suction of the flue, which will further press the deformation section to fit, eliminate dynamic gaps, and doubly block the backflow of oil fumes in the flue into the kitchen.

[0028] Furthermore, the connecting seat 2 includes a sheet-like base 2-1, with a through flow hole in the middle of the base 2-1, and the edge of the flow hole extending along its axial direction to form a snap ring 2-2.

[0029] A first L-shaped connecting ring 3-1 is wound around the outer ring wall of the air inlet end of the duckbill valve 3. The first L-shaped connecting ring 3-1 and the outer ring wall of the duckbill valve 3 form a first mounting groove that opens toward the base 2-1. The snap ring 2-2 is adapted to snap into the first mounting groove.

[0030] A second L-shaped connecting ring 3-2 is wound around the inner ring wall of the air inlet end of the duckbill valve 3. The second L-shaped connecting ring 3-2 and the inner ring wall of the duckbill valve 3 form a second mounting groove that opens toward the double-leaf check valve 1. The air outlet end of the double-leaf check valve 1 is adapted to be inserted into the second mounting groove.

[0031] The double L-shaped connecting rings of the duckbill valve 3 form double mounting grooves. During assembly, the snap ring 2-2 is first inserted into the first mounting groove. After the clamp is fitted around the outer periphery of the first L-shaped connecting ring 3-1, the assembly of the duckbill valve 3 and the connecting seat 2 is completed. Then, the air outlet end of the double-leaf check valve 1 is snapped into the second mounting groove, and the double-leaf check valve 1 is simultaneously inserted into the snap ring 2-2 of the connecting seat 2 to complete the assembly.

[0032] Furthermore, a tapered, gradually decreasing guide ring 4 is provided on the inner wall of the flue section near the air inlet side of the double-disc check valve 1. The inner diameter of the gradually decreasing guide ring 4 gradually decreases from the inlet end of the flue towards the double-disc check valve 1 along the airflow direction, and the minimum inner diameter of the gradually decreasing guide ring 4 is 8% to 15% smaller than the air inlet diameter of the double-disc check valve 1. There is a gap between the end of the gradually decreasing guide ring 4 and the air inlet of the double-disc check valve 1. This design allows the airflow to form an "acceleration effect" at the end of the guide ring, quickly impacting the valve plate of the double-disc check valve 1 and shortening the opening / closing response time of the valve plate of the double-disc check valve 1.

[0033] Furthermore, an annular groove 3-3 is provided on the outer wall of the outlet end of the duckbill valve 3. The cross-section of the groove 3-3 is U-shaped. On the side of the groove 3-3 near the outlet, a gradually tapering elastic deformation section 3-4 is formed. The tapering design makes the end elasticity of the deformation section better and the root strength higher. When a downward negative pressure suction force occurs in the flue, the negative pressure will act on the outside of the deformation section, pressing the deformation section inward and making the sealing surface fit more tightly.

[0034] Furthermore, at least four axially spaced strip-shaped reinforcing ribs 3-4.1 are provided on the outer surface of the outlet end of the elastic deformation section 3-4. The extension direction of the strip-shaped reinforcing ribs 3-4.1 is consistent with the airflow conduction direction of the duckbill valve 3. The strip-shaped reinforcing ribs 3-4.1 extend directly from the opening edge of the outlet end of the elastic deformation section 3-4 along the outer surface to the root of the groove wall near the outlet side of the groove 3-3, forming a "complete support from the end to the groove". The strip-shaped reinforcing ribs 3-4.1 can disperse the negative pressure and ensure that the deformation section closes uniformly in the width direction.

[0035] Furthermore, a ring-shaped reinforcing rib 3-3.1 protrudes from the bottom of the groove 3-3 of the duckbill valve 3. The cross-section of the reinforcing rib 3-3.1 is semi-circular, and its height is 1 / 3 to 1 / 2 of the depth of the U-shaped groove 3-3. The reinforcing rib 3-3.1 extends circumferentially along the bottom of the groove 3-3, and its two ends smoothly transition to the two side walls of the groove 3-3 through arc surfaces to avoid stress concentration caused by right-angle transitions. Under the continuous action of the negative pressure of the flue for a long time, the bottom of the groove 3-3 is a concentrated area of ​​deformation stress and is prone to cracks due to long-term deformation. The ring-shaped reinforcing rib 3-3.1 can disperse the deformation stress to the two side walls of the groove 3-3, thereby improving the bending fatigue resistance of the bottom of the groove 3-3 and maintaining a stable elastic closing force, avoiding sealing failure under negative pressure due to fatigue deformation. This forms a synergistic effect of "long-term durability + stable sealing" with the double-disc check valve 1.

[0036] Furthermore, the inner wall of the air inlet end of the duckbill valve 3 is provided with at least four axial guide ribs 3-5. The guide ribs 3-5 are integrally formed with the inner wall of the duckbill valve 3. The guide ribs 3-5 extend from the edge of the air inlet into the valve body. The length of the guide ribs 3-5 is 1 / 3 of the total length of the duckbill valve 3. The cross section is an isosceles triangle and is evenly distributed along the circumference. The triangular cross section can make the airflow smoothly split along the rib surface and avoid the generation of eddies. The guide ribs 3-5 can divide the airflow entering the duckbill valve 3 into a uniform airflow bundle and guide the airflow to flow along the inner wall of the valve body, reducing the generation of eddies. At the same time, it can avoid airflow pressure fluctuations caused by eddies, indirectly ensuring the stability of the opening and closing of the double-lobe check valve 1 and maintaining the smoke exhaust and sealing performance of the overall air duct.

[0037] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A backdraft preventing duct structure for a range hood, characterized by comprising: It includes a double-disc check valve, a connecting seat, and a duckbill valve connected in sequence. The main body of the duckbill valve is inserted into the flue inside the wall. The internal channels of the double-disc check valve, the connecting seat, and the duckbill valve together form an airflow channel that communicates with the flue. The air inlet of the duckbill valve and the air outlet of the double-leaf check valve are connected to each other via a connecting seat. The air inlet of the double-leaf check valve is connected to the exhaust end of the range hood via a smoke supply pipe.

2. The anti-backflow duct structure for a range hood according to claim 1, characterized in that, The connecting seat includes a sheet-shaped base with a through-hole in the center and the edge of the through-hole extending axially to form a snap ring. A first L-shaped connecting ring is wound around the outer ring wall of the air inlet end of the duckbill valve. The first L-shaped connecting ring and the outer ring wall of the duckbill valve form a first mounting groove facing the opening of the base. The snap-fit ​​ring is adapted to snap into the first mounting groove. A second L-shaped connecting ring is wound around the inner ring wall of the air inlet end of the duckbill valve. The second L-shaped connecting ring and the inner ring wall of the duckbill valve form a second mounting groove facing the opening of the double-leaf check valve. The air outlet end of the double-leaf check valve is adapted to be inserted into the second mounting groove.

3. The backdraft prevention duct structure for the exhaust hood according to claim 1, characterized by A tapered, gradually decreasing guide ring is provided on the inner wall of the flue section near the air inlet side of the double-disc check valve. The inner diameter of the gradually decreasing guide ring gradually decreases from the inlet end of the flue towards the double-disc check valve along the airflow direction. The minimum inner diameter of the gradually decreasing guide ring is 8% to 15% smaller than the air inlet diameter of the double-disc check valve. There is a gap between the end of the gradually decreasing guide ring and the air inlet of the double-disc check valve.

4. The anti-inrush air duct structure for a range hood according to claim 1, characterized by, The outlet end of the duckbill valve has an annular groove on its outer wall. The groove has a U-shaped cross-section, and the side of the groove near the outlet forms an elastic deformation section with gradually decreasing thickness.

5. The backdraft prevention duct structure for the extractor hood according to claim 4, characterized in that, On the outer surface of the outlet end of the elastic deformation section, at least four strip-shaped reinforcing ribs are provided at intervals along the axial direction. The extension direction of the strip-shaped reinforcing ribs is consistent with the airflow conduction direction of the duckbill valve. The strip-shaped reinforcing ribs extend directly from the opening edge of the outlet end of the elastic deformation section along the outer surface to the root of the groove wall near the outlet side.

6. The backdraft prevention duct structure for the exhaust hood according to claim 4, characterized by The bottom of the groove of the duckbill valve is provided with a ring of reinforcing ribs. The cross-section of the reinforcing ribs is semi-circular, and its height is 1 / 3 to 1 / 2 of the depth of the U-shaped groove. The reinforcing ribs extend circumferentially along the bottom of the groove, and their two ends are smoothly transitioned to the two side walls of the groove through arc surfaces.

7. The anti-influx air duct structure for a range hood according to claim 1, characterized by, The inner wall of the air inlet end of the duckbill valve is provided with at least 4 axial guide ribs. The guide ribs extend from the edge of the air inlet into the valve body. The length of the guide ribs is 1 / 3 of the total length of the duckbill valve. The cross section is an isosceles triangle and is evenly distributed along the circumference.

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