A range hood

Abstract

The present invention discloses a range hood, comprising a shell, a panel assembly arranged at the front side of the shell, a fan system and a smoke baffle arranged in the shell, the panel assembly comprising a panel bracket and a panel arranged at the front side of the panel bracket, the panel bracket is provided with a main air inlet, the fan system has a fan air inlet corresponding to the main air inlet, and is characterized in that: the panel bracket is recessed toward the inside of the shell at least at the main air inlet, a notch is arranged at the upper edge of the panel, the notch is fluidly connected to the main air inlet, a guide plate is arranged between the panel and the main air inlet, and the guide plate includes a guide portion corresponding to the notch. Compared with the prior art, the present invention has the advantages that: by arranging the guide plate at the notch of the panel for ventilation, a better gas wall attachment effect can be achieved, the laminar flow is increased, the turbulence is reduced, the gas is ensured to be subjected to less resistance, the smoking effect can be improved, and the flow loss of the gas is reduced, and the noise is reduced.

Description

Technical Field

[0001] The invention relates to an oil fume purification device, in particular to a range hood. Background Art

[0002] With the continuous pursuit of healthy and environmentally friendly living conditions, people pay more and more attention to indoor air quality. Building materials used in new house decoration usually release harmful gases such as formaldehyde for a long time. Living indoors for a long time will increase the concentration of carbon dioxide, affecting human health, and increase humidity, causing furniture and clothing to breed bacteria and cause mold.

[0003] As a traditional household appliance capable of purifying indoor air, the industry has also continuously introduced products with ventilation function (sucking fresh air from the outside into the room and exhausting harmful gases from the room to the outside). For example, a range hood with ventilation function disclosed in Chinese patent application number 201320589372.3 includes a chassis and a fan system arranged on the chassis, the chassis is provided with an air inlet, and also includes an ultra-low speed regulator for controlling the motor speed of the fan system between 200r / min and 400r / min, and a timer switch for timing and intermittently starting the motor of the fan system; the ultra-low speed regulator and the timer switch are both connected to the motor of the fan system.

[0004] However, the range hood's mission is to quickly absorb the fumes produced during cooking, and to ensure good extraction effect, the smoke baffle is usually opened to form a smoke cage and expose the air inlet, which will generate a lot of noise during its operation. Therefore, the ventilation function of this type of range hood has the disadvantage of high noise, especially at night when ventilating, which affects people's sleep. The common practice in the industry is to reduce the fan speed. Although the reduction of the fan speed can reduce noise, it also reduces the air volume, affecting the ventilation effect.

[0005] In addition, in order to quickly discharge the oil smoke and improve the oil smoke absorption effect, one method is to add an auxiliary air inlet channel. For example, the Chinese patent with application number 201610543688.7 discloses a range hood with an auxiliary air inlet channel. The range hood can make up for the discontinuity of the main air inlet by setting a long and horizontal auxiliary air inlet. The auxiliary air inlet can increase the air inlet area and change the oil smoke path. More oil smoke can be inhaled in the same time, and the oil smoke that easily escapes from the outer edge of the filter screen can be pulled back and captured. Due to the existence of the auxiliary air inlet's induced effect, the weakening of negative pressure and the escape of oil smoke caused by the smaller inclination angle of the smoke guide plate relative to the horizontal plane can be effectively overcome, thereby improving the smoking effect.

[0006] However, the oil filter plate and the smoke guide plate that constitute its auxiliary air inlet channel are both straight plates, and the oil filter plate and the smoke guide plate form a certain angle. Due to the viscosity of the gas, the flow field will form a boundary layer on the surface of the object. When the high-speed air intake passes through the flow channel, the gas flow cannot fit well at the interface between the fluid and the object, which leads to boundary layer separation and generates vortices on the back of the smoke guide plate. The generation of vortices leads to increased airflow resistance, aggravated flow losses, and increased noise.

[0007] To ensure the ejection effect of the auxiliary air inlet of the above-mentioned prior art, the core is to form a stable high flow rate of the auxiliary air inlet. In the above-mentioned patented technology, the same internal negative pressure cavity shared with the main air inlet is set, and the flow rate is achieved through the inlet distribution of the negative pressure cavity. The flow rate is restrained by the main air inlet, thus affecting the ejection effect. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a range hood that can achieve low-noise ventilation with small flow loss in view of the deficiencies in the above-mentioned prior art.

[0009] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a range hood, comprising a shell, a panel assembly arranged on the front side of the shell, a fan system and a smoke shield arranged in the shell, the panel assembly comprising a panel bracket and a panel arranged on the front side of the panel bracket, the panel bracket is provided with a main air inlet, the fan system has a fan air inlet corresponding to the main air inlet, and is characterized in that: the panel bracket is recessed toward the inside of the shell at least at the main air inlet, a notch is provided on the upper edge of the panel, the notch is fluidly connected to the main air inlet, a guide plate is provided between the panel and the main air inlet, and the guide plate includes a guide portion corresponding to the notch.

[0010] Preferably, to facilitate the connection between the gap and the main air inlet, the lower edge of the smoke shield in the closed state is higher than the lower edge of the main air inlet, and the upper edge of the panel is higher than the lower edge of the main air inlet, so that the smoke shield and the panel can jointly close the main air inlet.

[0011] In order to conveniently shield the oil stains inside the range hood, the highest point of the guide portion is higher than the lowest point when the smoke baffle is in a closed state, and the lowest point of the guide portion is lower than the lowest point of the notch.

[0012] In order to reflect the noise of the fan system and reduce the noise during ventilation, the projection of the guide portion on the fan inlet of the fan system covers the projection of the notch on the fan inlet of the fan system.

[0013] In order to reduce the dynamic pressure of the fluid and increase the static pressure of the fluid, the reduction of dynamic pressure can reduce noise, and the increase of static pressure can reduce the flow loss of the fluid. The channel between the main air inlet and the guide part constitutes an auxiliary air inlet channel. The upper end of the guide part corresponding to the auxiliary air inlet channel is the inlet of the auxiliary air inlet channel, and the lower end of the guide part corresponding to the auxiliary air inlet channel is the outlet of the auxiliary air inlet channel. The distance between the guide part and the main air inlet gradually increases from the inlet to the outlet of the auxiliary air inlet channel. A vent is provided on the panel bracket below the main air inlet, and the vent connects the auxiliary air inlet channel and the fan inlet fluid.

[0014] In order to further assist the vortex in the air inlet channel and reduce the flow loss of the gas, the surface of the guide portion facing the auxiliary air inlet channel is curved.

[0015] In order to better guide the airflow into the auxiliary air inlet channel and reduce eddy currents, the angle of attack formed by the tangent line at the uppermost end point of the guide portion and the main air inlet is β, and satisfies 0°≤β≤10°.

[0016] In order to improve the stability of the high flow rate of the auxiliary air inlet channel, the range hood also includes a partition, which extends between a side of the panel assembly facing the shell and a side of the fan inlet of the fan system facing the panel assembly, and the partition is in contact with the fan inlet, thereby forming a first negative pressure chamber above the partition and a second negative pressure chamber below the partition between the fan inlet of the fan system and the panel assembly, and the fan inlet is divided into a first air inlet above the partition and a second air inlet below the partition, the main air inlet is fluidly connected to the fan inlet of the fan system through the first negative pressure chamber, and the auxiliary air inlet channel is fluidly connected to the fan inlet of the fan system through the second negative pressure chamber.

[0017] In order to facilitate the distribution of the flow of the auxiliary air inlet channel according to the amount of oil smoke and ensure the entrainment effect of the auxiliary air inlet channel, the partition is movably connected to the panel assembly and can move up and down along the panel assembly to adjust the ratio of the first air inlet and the second air inlet.

[0018] Compared with the prior art, the advantages of the present invention are as follows: by arranging a guide plate at the notch of the panel for ventilation, a better gas wall attachment effect can be achieved, laminar flow is increased, turbulence is reduced, and the gas is ensured to be subjected to less resistance, which can improve the smoking effect, reduce the flow loss of gas, and reduce noise; by making the guide plate completely cover the notch in the vertical direction, the aesthetics can be improved, and at the same time, the oil stains inside the range hood can be blocked; by making the projection of the guide plate at the fan inlet of the fan system completely cover the notch, the guide plate can reflect the noise of the fan system, so that the noise generated by the fan system is not easy to be transmitted from the notch, thereby reducing the noise during ventilation; the auxiliary air inlet channel between the guide plate and the air inlet is gradually increased from the inlet to the outlet, reducing the dynamic pressure of the fluid and increasing the static pressure of the fluid. The reduction of dynamic pressure can reduce noise, and the increase of static pressure can reduce the flow loss of the fluid; by arranging a partition, the auxiliary air inlet channel can be made into an independent air duct, thereby ensuring the injection effect of the auxiliary air inlet channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the first embodiment of the range hood of the present invention in a closed state;

[0020] Figure 2 A schematic diagram of a first embodiment of a range hood according to the present invention in which a smoke baffle is hidden;

[0021] Figure 3 is a schematic diagram of a guide plate of a range hood of the present invention;

[0022] Figure 4 for Figure 1 A cross-sectional view of

[0023] Figure 5 It is a cross-sectional view of the first embodiment of the range hood of the present invention in an opened state;

[0024] Figure 6 for Figure 5 A partial enlarged schematic diagram of Ⅰ;

[0025] Figure 7 A cross-sectional view of a second embodiment of the range hood of the present invention in an opened state;

[0026] Figure 8 for Figure 7 A partial II enlarged schematic diagram of

[0027] Fig. 9 It is a cross-sectional view of a third embodiment of the range hood of the present invention in an opened state;

[0028] Fig.10 for Fig. 9 A partial III enlarged schematic diagram of

[0029] Fig.11It is a partial schematic diagram of the third embodiment of the range hood of the present invention, in which the partition is in a lowered and closed state. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Since the embodiments disclosed in the present invention can be set in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features.

[0032] Embodiment 1

[0033] See also Figure 1 to Figure 6 A range hood is a side suction range hood, comprising a housing 1, the front side of the housing 1 is open, a panel assembly 2 is arranged at the open portion of the housing 1, and a fan system 3 is arranged in the housing 1. The fan system 3 has a fan air inlet 31.

[0034] The panel assembly 2 includes a panel bracket 21 and a panel 22 arranged on the front side of the panel bracket 21. A main air inlet 23 is provided on the panel bracket 21. The panel 22 is located below the main air inlet 23. The fan air inlet 31 corresponds to the main air inlet 23 and is located at the rear side of the main air inlet 23. A smoke baffle 4 is provided on the panel assembly 2 at a position corresponding to the main air inlet 23. The smoke baffle 4 can be flipped relative to the panel assembly 2 to open or close the main air inlet 23. A filter 24 is provided at the main air inlet 23. The fan system 3 is fluidically connected to the main air inlet 23, so that the fan system 3 can inhale oil smoke or air through the main air inlet 23 when working. When the smoke baffle 4 is in a closed state, its lower edge is higher than the lower edge of the main air inlet 23, and the upper edge of the panel 22 is higher than the lower edge of the main air inlet 23, so that the main air inlet 23 is closed by the smoke baffle 4 and the panel 22. Like the existing range hood, an oil guide plate 7 is also provided between the fan air inlet 31 of the fan system 3 and the panel assembly 2, so that the oil smoke entering from the main air inlet 23 can only enter the fan air inlet 31 of the fan system 3 through the oil guide plate 7.

[0035] In this embodiment, the panel bracket 21 is recessed toward the inside of the housing 1 at least at the main air inlet 23. At least one notch 221 is provided on the upper edge of the panel 22, and the notch 221 is in fluid communication with the main air inlet 23, so that when the smoke baffle 4 is in a closed state, the fan system 3 can still be in communication with the outside of the range hood, and the airflow can enter the main air inlet 23 from the notch 221 to achieve the ventilation function.

[0036] The range hood further includes a guide plate 5, which is located between the panel 22 and the filter screen 24 (main air inlet 23). The guide plate 5 includes a mounting portion 51 and a guide portion 52, wherein the mounting portion 51 is used to be connected and fixed to the side of the panel 22 facing the inside of the housing 1, and the mounting portion 51 may be in a U-shape with an upper opening. The guide portion 52 is formed by the mounting portion 51 being recessed in the direction of the inside of the housing 1. In this embodiment, the guide portion 52 is recessed in the direction of the inside of the housing 1 from the inner circumference of the mounting portion 51.

[0037] The height of the notch 221 in the vertical direction is A. When the smoke shield 4 is closed, the height of the air guide 52 in the vertical direction is greater than the height of the notch 221, and the highest point of the air guide 52 is higher than the lowest point when the smoke shield 4 is closed, and the lowest point of the air guide 52 is lower than the lowest point of the notch 221, thereby satisfying the aesthetics when viewed from the front horizontal direction and shielding the internal oil stains of the range hood. The projection of the notch 221 on the fan air inlet 31 of the fan system 3 has a highest point and a lowest point, and the distance between the two points is B. The projection of the air guide 52 on the fan air inlet 31 of the fan system 3 covers the projection of the notch 221, thereby shielding and reflecting the noise generated by the fan system 3. When the smoke shield 4 is closed, the fan system 3 generates noise when it is working, and the smoke shield 4 plays a role in isolating and reflecting part of the noise. At the same time, because the air guide 5 shields and reflects the noise of the fan system 3, the noise generated by the fan system 3 is not easy to be transmitted from the notch 221, so the noise when the ventilation function is turned on is relatively low.

[0038] Figure 4 The middle arrow indicates the air flow path during ventilation. The airflow can enter the main air inlet 23 from the notch 221 to achieve the ventilation function. Figure 5 The middle long arrow indicates the main flow path of oil smoke, and the oil smoke enters the fan system 3 from the main air inlet 23. The short arrow indicates the auxiliary flow path of oil smoke, and the oil smoke passes through the vent 211 (opened below the filter 24) opened on the panel bracket 21 along the front side of the filter 24 from the space between the filter 24 and the guide part 52 and enters the space in front of the fan system 3 in the housing 1, and then enters the fan system 3, that is, the vent 211 connects the auxiliary air inlet channel Q3 and the fan air inlet 31 fluid. The channel between the filter 24 (main air inlet 23) and the guide part 52 constitutes the auxiliary air inlet channel Q3. The auxiliary air inlet channel Q3 corresponds to the upper end of the guide part 52 as the inlet of the auxiliary air inlet channel Q3, and the auxiliary air inlet channel Q3 corresponds to the lower end of the guide part 52 as the outlet of the auxiliary air inlet channel Q3. The distance between the guide part 52 and the filter 24 gradually increases from the inlet to the outlet of the auxiliary air inlet channel Q3. The principle of this feature is based on the fluid continuity equation and Bernoulli's principle. The gradual increase in distance is to reduce the dynamic pressure of the fluid and increase the static pressure of the fluid. The reduction of dynamic pressure can reduce noise, and the increase of static pressure can reduce the flow loss of the fluid.

[0039] The attack angle β of the air guide 52 (the angle between the tangent line at the uppermost end of the air guide 52 and the filter screen 24 (main air inlet 23)) ranges from 0°≤β≤10°, and the best angle is 0°, that is, the tangent line at the uppermost end of the air guide 52 is parallel to the filter screen 24. The longitudinal cross section of the air guide 52 is curved, and the best curved surface is a streamlined curved surface.

[0040] The resistance encountered by an object in a fluid is caused by two reasons: internal friction and vortex. When the speed is low, the magnitude of the resistance mainly depends on the internal friction. When the speed is high, it is mainly determined by the vortex. The vortex will increase the fluid resistance and increase the noise. The curved surface shape of the guide 52 can reduce the vortex in the auxiliary air inlet channel Q3 and reduce the flow loss of the gas. According to fluid mechanics, the gas has viscosity, and the flow field will form a boundary layer on the surface of the object. The thickness of the boundary layer is positively correlated with the viscous resistance of the flow. If the disturbance of the boundary layer is small, it will appear as laminar flow with small flow loss. If the disturbance of the boundary layer is large, turbulence will form and more energy will be lost. When the surface of the guide 52 facing the auxiliary air inlet channel Q3 is curved, the fluid and the back of the guide 52 have better flow fit, and a better gas wall attachment effect can be achieved, which is manifested as increased laminar flow and reduced turbulence. This can ensure that the gas is subjected to less resistance, improve the smoking effect, and reduce the flow loss of the gas.

[0041] Embodiment 2

[0042] See also Figure 7 and Figure 8 , different from the above-mentioned embodiment 1, in this embodiment, a partition plate 6 is further included, and the partition plate 6 extends between the side of the panel assembly 2 facing the inside of the housing 1 and the side of the fan air inlet 31 of the fan system 3 facing the panel assembly 2. The partition plate 6 is preferably L-shaped, with a portion thereof connected and fixed to the panel bracket 21, and another relatively bent portion extending between the side of the panel assembly 2 facing the inside of the housing 1 and the side of the fan air inlet 31 of the fan system 3 facing the panel assembly 2, and abutting against the fan air inlet 31.

[0043] Thus, a first negative pressure chamber Q1 located above the partition 6 and a second negative pressure chamber Q2 located below the partition 6 are formed between the fan air inlet 31 of the fan system 3 and the panel assembly 2. The fan air inlet 31 of the fan system 3 is divided into a first air inlet 311 located above the partition 6 and a second air inlet 312 located below the partition 6. The main air inlet 23 is in fluid communication with the fan air inlet 31 of the fan system 3 through the first negative pressure chamber Q1, and the auxiliary air inlet channel Q3 is in fluid communication with the fan air inlet 31 of the fan system 3 through the second negative pressure chamber Q2.

[0044] By setting the partition 6 as the auxiliary air inlet channel Q3, an independent air inlet channel to the fan system 3 is formed, thereby matching the independent air volume from the fan system 3 to obtain a stable high flow rate of the auxiliary air inlet channel Q3, thereby improving the injection effect of the auxiliary air inlet channel Q3.

[0045] Embodiment 3

[0046] See also Figure 9-10The partition 6 is a movable partition that can be moved up and down along the panel assembly 2 to adjust the ratio of the first air inlet 311 and the second air inlet 312. For example, when stir-frying, the amount of oil smoke is large and oil smoke is prone to escape. At this time, it is necessary to improve the auxiliary air intake effect, control the partition 6 to move upward, increase the area of ​​the second air inlet 312 of the fan system 3, thereby increasing the flow of the auxiliary air inlet channel Q3, and then improve the auxiliary air intake effect. Fig.11 When the amount of oil smoke is small, the auxiliary air inlet channel Q3 can be closed to shorten the oil smoke inlet path and realize rapid oil smoke suction and exhaust; when in the ventilation function, the auxiliary air inlet channel Q3 can be closed to make the ventilation duct more unobstructed. By moving the partition 6 downward to abut against the part of the fan air inlet 31 located outside the second air inlet 312 of the fan system 3, such as the fan air inlet 31 generally includes an annular mounting portion connected to the volute of the fan system 3, a radial guide portion extending radially inwardly from the mounting portion, and an axial guide portion extending axially into the volute from the radial inwardly of the radial guide portion, the middle of the radial guide portion and the axial guide portion is available for oil smoke gas to enter, and when the partition 6 abuts against the mounting portion or the radial guide portion at the bottom of the fan air inlet 31, the position where the fan system 3 can enter air is completely isolated above the partition 6, so that the auxiliary air inlet channel Q3 is closed, and the airflow cannot enter the fan system 3 from the auxiliary air inlet channel Q3.

[0047] By providing a movable partition 6, the flow rate distributed by the fan system 3 to the independent air duct can be controlled, thereby ensuring the ejection effect of the auxiliary air inlet channel Q3.

[0048] The "fluid connection" referred to in the present invention refers to the spatial position relationship between two parts or parts (hereinafter collectively referred to as the first part and the second part respectively), that is, the fluid (gas, liquid or a mixture of the two) can flow from the first part along the flow path or / and be transported to the second part. The first part and the second part can be directly connected, or the first part and the second part can be indirectly connected through at least one third party. The third party can be a fluid channel such as a pipe, channel, duct, guide member, hole, groove, etc., or it can be a chamber allowing fluid to flow through, or a combination of the above.

Claims

1. A range hood, comprising a housing (1), a panel assembly (2) arranged at the front side of the housing (1), a fan system (3) arranged in the housing (1) and a smoke baffle (4), wherein the panel assembly (2) comprises a panel bracket (21) and a panel (22) arranged at the front side of the panel bracket (21), the panel bracket (21) is provided with a main air inlet (23), the fan system (3) has a fan air inlet (31) corresponding to the main air inlet (23), and is characterized in that: The panel bracket (21) is recessed at least at the main air inlet (23) in a direction toward the inside of the shell (1); a notch (221) is provided at the upper edge of the panel (22); the notch (221) is in fluid communication with the main air inlet (23); a guide plate (5) is provided between the panel (22) and the main air inlet (23); the guide plate (5) comprises a mounting portion (51) and a guide portion (52) corresponding to the notch (221); the mounting portion (51) is used to be connected and fixed to a side of the panel (22) facing the inside of the shell (1); the guide portion (52) is formed by the mounting portion (51) being recessed in a direction toward the inside of the shell (1); The highest point of the guide portion (52) is higher than the lowest point of the smoke baffle (4) when it is in a closed state, and the lowest point of the guide portion (52) is lower than the lowest point of the notch (221); The projection of the air guide portion (52) on the fan air inlet (31) of the fan system (3) covers the projection of the notch (221) on the fan air inlet (31) of the fan system (3).

2. The range hood according to claim 1, characterized in that: The lower edge of the smoke shield (4) when in a closed state is higher than the lower edge of the main air inlet (23), and the upper edge of the panel (22) is higher than the lower edge of the main air inlet (23); the smoke shield (4) and the panel (22) can jointly close the main air inlet (23).

3. The range hood according to claim 1 or 2, characterized in that: The channel between the main air inlet (23) and the guide portion (52) constitutes an auxiliary air inlet channel (Q3); the upper end of the auxiliary air inlet channel (Q3) corresponding to the guide portion (52) is the inlet of the auxiliary air inlet channel (Q3); the lower end of the auxiliary air inlet channel (Q3) corresponding to the guide portion (52) is the outlet of the auxiliary air inlet channel (Q3); the distance between the guide portion (52) and the main air inlet (23) gradually increases from the inlet to the outlet of the auxiliary air inlet channel (Q3); a vent (211) is provided on the panel bracket (21) below the main air inlet (23); the vent (211) connects the auxiliary air inlet channel (Q3) and the fan air inlet (31) fluidically.

4. The range hood according to claim 3, characterized in that: The surface of the air guide portion (52) facing the auxiliary air inlet channel (Q3) is in a curved shape.

5. The range hood according to claim 1 or 2, characterized in that: The angle of attack formed by the tangent line at the uppermost end point of the air guide portion (52) and the main air inlet (23) is β, and satisfies 0°≤β≤10°.

6. The range hood according to claim 1 or 2, characterized in that: The range hood further comprises a partition (6), the partition (6) extending between a side of the panel assembly (2) facing the inside of the housing (1) and a side of the fan air inlet (31) of the fan system (3) facing the panel assembly (2), the partition (6) abutting against the fan air inlet (31), thereby forming a first negative pressure chamber (Q1) located above the partition (6) and a negative pressure chamber (Q2) located above the partition (6) between the fan air inlet (31) of the fan system (3) and the panel assembly (2). The second negative pressure chamber (Q2) is located below the partition (6), the fan air inlet (31) is divided into a first air inlet (311) located above the partition (6) and a second air inlet (312) located below the partition (6), the main air inlet (23) is fluidically connected to the fan air inlet (31) of the fan system (3) through the first negative pressure chamber (Q1), and the auxiliary air inlet channel (Q3) is fluidically connected to the fan air inlet (31) of the fan system (3) through the second negative pressure chamber (Q2).

7. The range hood according to claim 6, characterized in that: The partition plate (6) is movably connected to the panel assembly (2) and can move up and down along the panel assembly (2) to adjust the ratio of the first air inlet (311) and the second air inlet (312).

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