A range hood

Abstract

The application discloses a kind of range hood, including fan frame, lower box body being arranged below fan frame and fan being arranged in fan frame, the noise reduction device is arranged in the lower box body, and the noise reduction device includes sound-absorbing box and sound-absorbing material being arranged in sound-absorbing box;The sound-absorbing box has the first side wall towards oil fume side and the second side wall opposite to the first side wall, the first side wall is opened with the noise reduction hole, and the sound-absorbing material is attached to the inboard of the first side wall of sound-absorbing box, space is formed in the sound-absorbing box between the second side wall and sound-absorbing material and forms flow-through cavity, and the flow-through cavity is in fluid communication with the outside of sound-absorbing box and can be into gas, and the gas into flow-through cavity flows out the outside of sound-absorbing box via sound-absorbing material and noise reduction hole.

Description

Technical Field

[0001] This invention relates to an oil fume purification device, and more particularly to an oil fume extractor. Background Technology

[0002] Range hoods have become an indispensable kitchen appliance in modern homes. They operate on the principles of fluid dynamics, using a centrifugal fan inside to draw in cooking fumes and a filter to remove some grease particles. The centrifugal fan consists of a casing, an impeller housed within the casing, and a motor that drives the impeller. As the impeller rotates, a negative pressure is generated at the center of the fan, drawing in the cooking fumes from below. After being accelerated by the fan, the fumes are collected by the casing and guided outdoors.

[0003] Currently, the noise of range hoods mainly comes from aerodynamic noise, mechanical noise, and electromagnetic noise, with aerodynamic noise being the primary source. Aerodynamic noise includes rotational noise and eddy current noise, with rotational noise being the main source. Rotational noise is inevitably generated by the structure itself under high-speed rotation. Simply changing the structure of the fan system (such as the trailing edge of the blades, the volute, the impeller disc, the volute profile, etc.) can generally only reduce noise by less than 0.5dB. This is because, to achieve a certain airflow while maintaining performance, a certain rotational speed must be reached. Under high-speed rotation, there will inevitably be rotational noise, and 70% of the noise we hear comes from rotational noise.

[0004] Therefore, a generally better noise reduction measure is to apply passive noise reduction. Currently, porous sound-absorbing materials (such as sound-absorbing cotton) are widely used for noise reduction in range hoods. However, the use of porous sound-absorbing materials has the following problems: 1) contact with the smoke and fumes; 2) dripping or flowing oil from other structures. After a period of use, porous sound-absorbing materials will accumulate a large amount of oil. After absorbing oil, the air in the gaps and pores of the material is replaced by oil, which reduces the porosity and thus greatly affects its sound absorption performance and degrades its noise reduction effect.

[0005] Some patents have disclosed solutions to the above problems. For example, Chinese patent application number 201811214518.X uses the method of replacing sound-absorbing cotton to ensure the noise reduction effect. The disadvantage is that it requires material replacement, which brings consumable expenses and replacement trouble to users. Another example is Chinese patent application number 202120537541.3, which uses the method of squeezing the sound-absorbing cotton to squeeze out the oil stains in the sound-absorbing cotton to ensure the sound absorption effect. The disadvantages are: 1) oil stains remain after squeezing; 2) the oil stains are sticky and cannot restore the original porosity after squeezing; 3) an additional motor power source is required, which is costly. Yet another example is Chinese patent application number 201820994547.1, which uses an oil guiding component to prevent oil stains from dripping onto the noise reduction component. The disadvantage is that it cannot avoid oil vapor in the oil fume gas from contaminating the porous sound-absorbing material. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a range hood that cuts off the gas phase pollution channels of the sound-absorbing material, extends its service life, and ensures a stable noise reduction effect.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problem is as follows: a range hood, comprising a fan frame, a lower housing disposed below the fan frame, and a fan disposed within the fan frame, wherein a noise reduction device is disposed within the lower housing, the noise reduction device comprising a sound-absorbing box and sound-absorbing material disposed within the sound-absorbing box; characterized in that:

[0008] The sound-absorbing box has a first sidewall facing the oil fume side and a second sidewall opposite to the first sidewall. Noise reduction holes are provided on the first sidewall. The sound-absorbing material is attached to the inner side of the first sidewall of the sound-absorbing box. A space is formed inside the sound-absorbing box between the second sidewall and the sound-absorbing material to form a flow cavity. The flow cavity is in fluid communication with the outside of the sound-absorbing box and can allow gas to enter. The gas entering the flow cavity flows out of the sound-absorbing box through the sound-absorbing material and the noise reduction holes.

[0009] Back pressure is applied at the sound-absorbing box, and the gas flows out from the noise reduction hole into the mainstream field. This makes it difficult for the oil fume gas in the mainstream field to enter the sound-absorbing material, cuts off the gas phase pollution channel of the sound-absorbing material, and thus extends the service life of the sound-absorbing material. Since the sound-absorbing material can stay clean for a long time, the noise reduction effect of the range hood can be stabilized.

[0010] Furthermore, to facilitate the placement of sound-absorbing material, the noise reduction device also includes a support column extending from the inner side of the second side wall of the sound-absorbing box to the first side wall, thereby bringing the sound-absorbing material close to the first side wall of the sound-absorbing box.

[0011] Furthermore, a flange is provided on the outer side of the first sidewall of the sound-absorbing box along the edge of the noise reduction hole, thereby preventing oil stains from entering the sound-absorbing box through the noise reduction hole.

[0012] Furthermore, the flow cavity is connected to the fluid inside the fan, thereby introducing gas from inside the fan. This allows the airflow drawn from the fan to be used as a power source, eliminating the need for an additional motor and reducing costs.

[0013] Furthermore, the range hood also includes an oil-gas separation component connected between the fan and the flow chamber. The fan includes a volute, and the oil-gas separation component includes a drain nozzle disposed on the volute and a condenser pipe for fluid communication between the drain nozzle and the flow chamber. The drain nozzle is fluidly connected to the inside of the volute, thereby condensing the airflow drawn out from the fan, liquefying the gaseous grease, separating it from the air, and achieving the cleanliness of the back pressure gas.

[0014] Preferably, the condenser tube includes a first tube segment connected to a drain nozzle and a second tube segment connected to the end of the first tube segment away from the drain nozzle, the first tube segment being at least partially spiral-shaped, and the second tube segment extending downward from the connection point with the first tube segment.

[0015] Preferably, to ensure uniform airflow into the flow chamber, the oil-gas separation assembly further includes a diverter pipe and a diffuser pipe. The diffuser pipe has at least two spaced apart. The diffuser pipe is connected to the sound-absorbing box and is in fluid communication with the flow chamber inside the sound-absorbing box. The diverter pipe is connected between the condenser pipe and the diffuser pipe and is in fluid communication with both the condenser pipe and the diffuser pipe respectively. The flow area of ​​the diffuser pipe is larger than the flow area of ​​the diverter pipe.

[0016] Preferably, to avoid the airflow from the opening of the sound-absorbing box interfering with the main field, the airflow velocity V at the noise reduction hole of the sound-absorbing box is set to... k The velocity V of the oily fume airflow flowing through the first side wall of the sound-absorbing box Z The following relationship must be satisfied:

[0017] 1%*V Z ≤V K ≤10%*V Z

[0018] and

[0019]

[0020] Among them, Q YM A1 is the air volume at the maximum setting of the range hood, A1 is the ventilation area through which the fumes pass in the lower casing, and K1 is the flow distribution coefficient, with a value ranging from 0.7 to 1.3.

[0021] Preferably, the pressure drop of the airflow at the nozzle and the flow cavity is Δp1:

[0022]

[0023] Wherein, ρ is the gas density flowing through the oil-gas separation component, and the value of ρ ranges from 1.27 to 1.31 kg / m³. 3 L F L represents the total length of the condenser tubes of the oil-gas separation assembly. F The value range is 300mm to 1000mm, D F D is the inner diameter of the condenser tube of the oil-gas separator assembly. F The value of f ranges from 5 to 30 mm, and f is the frictional resistance coefficient of gas flowing in the oil-gas separation component, with a value range of 0.01 to 0.05.

[0024] V F Let be the gas flow rate in the oil-gas separation assembly before diversion, and satisfy:

[0025] V F *A F =V K *A K

[0026] thus

[0027]

[0028] Among them, A F A is the cross-sectional area of ​​the condenser tube of the oil-gas separator assembly. K It is the total area of ​​the noise reduction holes in the sound-absorbing box, D i D is the diameter of the noise reduction aperture. i The value range is 2mm to 20mm, thus making V... K Satisfying V Z The proportional relationship.

[0029] Therefore, by designing the size parameters of the oil-gas separation component, it is possible to ensure that the airflow at the noise reduction holes of the sound-absorbing box does not interfere with the mainstream field.

[0030] Preferably, the pressure drop of the airflow through the sound-absorbing material is Δp2:

[0031]

[0032] In the above formula:

[0033]

[0034]

[0035] Where L is the thickness of the sound-absorbing material, and the value of L ranges from 10mm to 50mm, G rpFor the corrected Reynolds number, G rp The value range of D is 1000 to 10000. p D is the equivalent average pore size of the sound-absorbing material. p The value of μ ranges from 1 μm to 100 μm, and μ is the gas dynamic viscosity, ranging from 14.7 to 14.9 × 10⁻⁶. -6 m 2 / s, where ε is the porosity of the sound-absorbing material, and the value of ε ranges from 70% to 95%, thus making V K Satisfying V Z The proportional relationship.

[0036] Therefore, by designing the size parameters of the sound-absorbing material, it is possible to ensure that the airflow at the noise reduction holes of the sound-absorbing box does not interfere with the mainstream field.

[0037] Compared with the prior art, the advantages of this invention are as follows: By applying back pressure at the sound-absorbing box, gas flows out from the noise reduction hole into the mainstream field, making it difficult for oily fumes in the mainstream field to enter the sound-absorbing material, cutting off the gas phase pollution channel of the sound-absorbing material, thereby extending the service life of the sound-absorbing material. Since the sound-absorbing material can remain clean for a long time, the noise reduction effect of the range hood can be stabilized. Using the airflow drawn from the fan as a power source, no additional motor is needed, resulting in lower costs. The airflow drawn from the fan is condensed, causing the gaseous grease to liquefy and separate from the air, achieving the cleanliness of the back pressure gas. The outlet flow rate at the opening of the sound-absorbing box is controlled, ensuring the oil fume prevention effect while reducing the interference of the airflow flowing out from the opening of the sound-absorbing box on the mainstream field. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a range hood according to an embodiment of the present invention;

[0039] Figure 2 This is a cross-sectional view of a range hood according to an embodiment of the present invention;

[0040] Figure 3 for Figure 2 A magnified schematic diagram of part I;

[0041] Figure 4 This is a top sectional view of the range hood according to an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of the fan casing and noise reduction device of the range hood according to an embodiment of the present invention;

[0043] Figure 6 This is an exploded structural diagram of the noise reduction device of the range hood according to an embodiment of the present invention. Detailed Implementation

[0044] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions.

[0045] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Since the embodiments disclosed in this invention can be arranged in different directions, these terms indicating direction are only for illustration and should not be regarded as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity. In addition, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0046] See Figures 1-6 A range hood includes a fan frame 1, a lower housing 2 disposed below the fan frame 1, an air inlet assembly 3 disposed below the lower housing 2, and a fan 4 disposed within the fan frame 1. Cooking fumes enter through the air inlet assembly 3, pass through the lower housing 2 into the fan frame 1, and are exhausted by the fan 4. Alternatively, the air inlet assembly 3 may not be separately provided, and the lower housing 2 may be used directly for air intake.

[0047] The lower housing 2 is located below the fan frame 1. Noise reduction devices and oil-gas separation components are installed inside both the lower housing 2 and the fan frame 1. The noise reduction device includes a hollow sound-absorbing box 51, sound-absorbing material 52 disposed within the sound-absorbing box 51, and a support column 53. The sound-absorbing material 52 is a porous sound-absorbing material. The sound-absorbing box 51 can be fixed to the inner wall of the lower housing 2. The sound-absorbing box 51 has a first side wall 511 facing the oil fume side and a second side wall 512 opposite to the first side wall 511. Noise reduction holes 513 are provided on the first side wall 511, preferably in a circular shape. The second side wall 512 is used for fixing to the inner wall of the lower housing 2. The sound-absorbing material 52 can be tightly adhered to the inner side of the first sidewall 511 of the sound-absorbing box 51, while the support column 53 extends from the inner side of the second sidewall 512 of the sound-absorbing box 51 towards the first sidewall 511, thus tightly adhering the sound-absorbing material 52 to the first sidewall 511 of the sound-absorbing box 51. The space inside the sound-absorbing box 51 between the second sidewall 512 and the sound-absorbing material 52 forms a flow cavity 54, and at least two support columns 53 can be arranged at intervals within the flow cavity 54. On the outer side of the first sidewall 511 of the sound-absorbing box 51, a flange 514 is provided along the edge of the noise reduction hole 513 to prevent oil stains from entering the interior of the sound-absorbing box 51.

[0048] The oil-gas separation assembly includes a flow inlet 61, a condenser pipe 62, a branch pipe 63, and a diffuser pipe 64. The flow inlet 61 is mounted on the volute 41 of the blower 4 and is in fluid communication with the interior of the volute 41. The condenser pipe 62 is connected to the flow inlet 61 and the two are in fluid communication. The condenser pipe 62 may include a first pipe section 621 connected to the flow inlet 61 and a second pipe section 622 connected to the end of the second pipe section 621 away from the flow inlet 61. These two pipe sections can be integrally formed. Preferably, the first pipe section 621 may be at least partially spiral-shaped and may be fitted with a water-cooling jacket to further improve the condensation effect. It extends upward from the connection point with the flow inlet 61 to prolong the condensation time and improve the condensation effect. The second pipe section 622 extends downward from the connection point with the first pipe section 621. The first pipe section 621 and the second pipe section 622 are pipes of equal diameter.

[0049] The flow area of ​​the diffuser 64 is larger than that of the diverter 63. The diffuser 64 is connected to the sound-absorbing box 51 and is in fluid communication with the flow cavity 54 inside the sound-absorbing box 51. There may be at least two diffusers 64, their positions corresponding to the spaces between two adjacent support columns 53. The diverter 63 includes a horizontal pipe section 631 extending laterally above the sound-absorbing box 51 and a vertical pipe section 632 extending downward from the horizontal pipe section 631. The extension direction of the horizontal pipe section 631 is consistent with the width direction of the sound-absorbing box 51; in this embodiment, it extends left and right. The number of vertical pipe sections 632 matches the number of diffusers 64, both having at least two. Each vertical pipe section 632 corresponds to one diffuser 64, and each vertical pipe section 632 is connected between the horizontal pipe section 631 and the corresponding diffuser 64, so that the airflow from the fan 4 enters the flow cavity 54 evenly. In this embodiment, the diffuser 64 is located at the top of the sound-absorbing box 61.

[0050] The exhaust nozzle 61 draws out the oil fume airflow from the volute 41 of the fan 4. After entering the condenser pipe 62, the volatile organic compounds in the oil fume are liquefied by the cold air and return to the volute 41 from the exhaust nozzle 61 under the action of gravity. The gas after grease separation enters the flow cavity 54 in the sound absorption box 51 through the structure of the diverter pipe 63 and the diffuser pipe 64 (the diverter pipe 62 and the diffuser pipe 63 can make the air pressure distribution in the flow cavity 54 in the sound absorption box 51 relatively uniform). Then the gas passes through the sound-absorbing material 52 and flows out from the noise reduction hole 53 of the sound absorption box 51, avoiding the pollution of the sound-absorbing material 52 by unpurified oil fume gas.

[0051] As can be seen from the above, some of the gas flowing out of the noise reduction hole 513 enters the original oil fume channel (mainstream field). Therefore, while ensuring the oil fume prevention effect, it is necessary to reduce the interference of the airflow flowing out of the noise reduction hole 513 of the sound-absorbing box 51 on the mainstream field. To achieve the above goal, the airflow velocity V at the noise reduction hole 513 of the sound-absorbing box 51 is... k (m / s) and the velocity V of the mainstream airflow near the sound-absorbing box 51 Z (m / s) should satisfy the following relationship:

[0052] 1%*V Z ≤V k ≤10%*V Z

[0053] V Z It can be estimated using the following formula:

[0054]

[0055] In the formula: Q YM This refers to the airflow (m³ / h) at the maximum fan speed setting of the range hood. 3 The range hood's capacity ( / min) is determined by its design parameters, typically ranging from 18 to 30 m. 3 / min; A1 is the cross-sectional area of ​​the range hood cavity on a plane perpendicular to the direction of the mainstream airflow near the sound-absorbing box 51, determined by the mechanical structure of the range hood. In this embodiment, it is the ventilation area for the oil fumes to pass through inside the lower box 2, i.e., the area of ​​the horizontal cross-section. See [reference needed]. Figure 4 The horizontal cross-section is T-shaped, preferably 0.1–0.5 m. 2 K1 is the flow distribution coefficient, which is a coefficient added to correct uneven spatial distribution of flow. The specific value depends on the mechanical structure of the range hood and is usually between 0.7 and 1.3.

[0056] During the flow of air from the inlet nozzle 61 into the sound-absorbing box 51, there is continuous pressure loss along the flow path. For a range hood with a defined structure, operating conditions, and fan system, the total pressure at the inlet nozzle 61 is fixed, and the total pressure at the main flow field inside the lower casing 2 is also fixed, satisfying the following formula:

[0057] Δp=Δp1+Δp2

[0058] Wherein: Δp is the total pressure difference between the drain nozzle 61 and the main flow field inside the lower box 2, which is determined by the structure and operating conditions of the range hood; Δp1 is the pressure difference between the drain nozzle 61 and the flow cavity 54, and its influencing factors are detailed below; Δp2 is the pressure difference between the flow cavity 54 and the main flow field inside the lower box 2, and its influencing factors are detailed below.

[0059] To ensure that the airflow velocity V at the outlet is reduced after passing through the slender pipe of the oil-gas separator and the 52 flow losses of the sound-absorbing material, k To meet the above requirements, the dimensional parameters of the oil-gas separation component and the sound-absorbing material 52 need to be designed as follows.

[0060] 1. Pressure drop Δp1 of airflow at the nozzle and flow cavity sections

[0061] Based on the Darcy-Weisbach formula for the pressure drop along a rough pipe during steady flow of an incompressible viscous fluid:

[0062]

[0063] Where: Δp1 is the pressure difference between the drain nozzle 61 and the flow chamber 54; ρ is the density of the oil fume gas flowing through the oil-gas separator, which is affected by ambient temperature, air pressure, etc., and is usually between 1.27 and 1.31 kg / m³. 3 L F The total length of the condenser tube 62 of the oil-gas separator assembly is preferably 300mm to 1000mm; D F The inner diameter of the condenser tube 62 of the oil-gas separation component is preferably 5–30 mm; V FThe gas velocity in the oil-gas separation assembly before diversion is given below for calculation details; f is the frictional resistance coefficient of the gas flowing in the oil-gas separation assembly, which is usually between 0.01 and 0.05.

[0064] In the above formula, the flow velocity V F The calculation method is as follows:

[0065] Air can be considered an incompressible fluid at low speeds. For incompressible fluids, the law of conservation of mass readily applies.

[0066] V F *A F =V K *A K

[0067] Right now

[0068]

[0069] Among them: A F It is the cross-sectional area of ​​the condenser tube 62 of the oil-gas separation assembly, and its range can be determined by D. F Calculated; D F The inner diameter of the condenser tube 62 of the oil-gas separation component is preferably 5–30 mm; A K The total area of ​​the noise reduction holes 513 in the sound-absorbing box 51 is the product of the area of ​​a single noise reduction hole 513 and the number of noise reduction holes 513 n. The aperture degree γ is defined as the total area of ​​the openings A of the sound-absorbing box 51. K The ratio of γ to the total area of ​​the outer wall surface of the first side wall 511 of the sound-absorbing box 51 is preferably 5% to 30%; D i The preferred diameter of the noise reduction hole 513 on the sound-absorbing box 51 is 2mm to 20mm.

[0070] 2. Pressure drop Δp2 of airflow passing through sound-absorbing material

[0071] For porous media, the pressure drop across them can be estimated using the Ergun formula:

[0072]

[0073]

[0074]

[0075] Where: Δp2 is the pressure drop of airflow through the sound-absorbing material 52; L is the thickness of the sound-absorbing material 52, preferably ranging from 10mm to 50mm; G rp The preferred range for the corrected Reynolds number is 1000 to 10000; D pThe equivalent average pore size is determined by the pore size of the sound-absorbing material 52 itself, and the preferred value range is 1µm to 100µm; μ is the fluid dynamic viscosity, which is affected by pressure, temperature, and gas type, and the dynamic viscosity is usually between 14.7 and 14.9 × 10⁻⁶. -6 m 2 The value is between / s; ε is the porosity of the sound-absorbing material 52, which is determined by the sound-absorbing material 52 itself, and the preferred value range is 70% to 95%.

[0076] Based on the pressure difference between the drain nozzle 62 and the lower housing 2, the above formula can be used to rationally design structural parameters such as the pipe length and inner diameter of the oil-gas separation component, the number and size of the openings in the sound-absorbing box, and the thickness of the sound-absorbing material, so that the flow velocity at the sound-absorbing box 51 is within a reasonable range.

[0077] The term "fluid connectivity" as used in this invention refers to the spatial relationship between two components or parts (hereinafter referred to as the first part and the second part, respectively), that is, a fluid (gas, liquid, or a mixture of both) can flow from the first part along a flow path and / or be transported to the second part. This can be a direct connection between the first part and the second part, or an indirect connection between the first part and the second part through at least one third party. This third party can be a fluid channel such as a pipe, channel, conduit, guide, hole, or groove, or a chamber or combination thereof that allows fluid to flow through.

Claims

1. A range hood, comprising a fan frame (1), a lower housing (2) disposed below the fan frame (1), and a fan (4) disposed within the fan frame (1), wherein a noise reduction device is disposed within the lower housing (2), the noise reduction device comprising a sound-absorbing box (51) and sound-absorbing material (52) disposed within the sound-absorbing box (51); characterized in that: The sound-absorbing box (51) has a first sidewall (511) facing the oil fume side and a second sidewall (512) opposite to the first sidewall (511). A noise reduction hole (513) is provided on the first sidewall (511). The sound-absorbing material (52) is attached to the inside of the first sidewall (511) of the sound-absorbing box (51). A space is formed in the sound-absorbing box (51) between the second sidewall (512) and the sound-absorbing material (52) to form a flow cavity (54). The flow cavity (54) is fluidly connected to the outside of the sound-absorbing box (51) and can allow gas to pass through. The gas entering the flow cavity (54) flows out of the sound-absorbing box (51) through the sound-absorbing material (52) and the noise reduction hole (513). The flow chamber (54) is in fluid communication with the fan (4), thereby introducing gas from the fan (4). The range hood also includes an oil-gas separation assembly connected between the fan (4) and the flow chamber (54). The fan (4) includes a volute (41). The oil-gas separation assembly also includes a drain nozzle (61) disposed on the volute (41) and a condenser pipe (62) for fluid communication between the drain nozzle (61) and the flow chamber (54). The drain nozzle (61) is in fluid communication with the inside of the volute (41).

2. The range hood according to claim 1, characterized in that: The noise reduction device also includes a support column (53), which extends from the inside of the second side wall (512) of the sound-absorbing box (51) to the first side wall (511), thereby bringing the sound-absorbing material (52) close to the first side wall (511) of the sound-absorbing box (51).

3. The range hood according to claim 1, characterized in that: A flange (514) is provided on the outer side of the first sidewall (511) of the sound-absorbing box (51) along the edge of the noise reduction hole (513).

4. The range hood according to any one of claims 1 to 3, characterized in that: The condenser tube (62) includes a first tube section (621) connected to a drain nozzle (61) and a second tube section (622) connected to the end of the first tube section (621) away from the drain nozzle (61). The first tube section (621) is at least partially spiral-shaped, and the second tube section (622) extends downward from the connection with the first tube section (621).

5. The range hood according to any one of claims 1 to 3, characterized in that: The oil-gas separation assembly further includes a diverter pipe (63) and a diffuser pipe (64). The diffuser pipe (64) has at least two spaced apart. The diffuser pipe (64) is connected to the sound-absorbing box (51) and is in fluid communication with the flow cavity (54) inside the sound-absorbing box (51). The diverter pipe (63) is connected between the condenser pipe (62) and the diffuser pipe (64) and is in fluid communication with the condenser pipe (62) and the diffuser pipe (64) respectively. The flow area of ​​the diffuser pipe (64) is larger than the flow area of ​​the diverter pipe (63).

6. The range hood according to any one of claims 1 to 3, characterized in that: The airflow velocity at the noise reduction hole (513) of the sound-absorbing box (51) The velocity of the oil fume flow passing through the first sidewall (511) of the sound-absorbing box (51) The following relationship must be satisfied: and in, This refers to the airflow at the highest setting of the range hood. The ventilation area for oil fumes to pass through inside the lower casing (2) For flow allocation coefficient, The value range is 0.7 to 1.

3.

7. The range hood according to claim 6, characterized in that: The pressure drop of the airflow at the nozzle (61) and the flow chamber (54) is: : in, The density of the gas flowing through the oil-gas separator component. The value range is 1.27~1.31 kg / m³ 3 , The total length of the condenser tube (62) of the oil-gas separation assembly. The value range is 300mm~1000mm. The inner diameter of the condenser tube (62) of the oil-gas separation assembly. The value range is 5~30mm. The coefficient of friction resistance for gas flow within the oil-gas separator assembly. The value range is 0.01 to 0.05; Let be the gas flow rate in the oil-gas separation assembly before diversion, and satisfy: thus in, It is the cross-sectional area of ​​the condenser tube (62) of the oil-gas separation assembly. It is the total area of ​​the noise reduction holes (513) of the sound-absorbing box (51). The diameter of the noise reduction hole (513) is... The value range is 2mm~20mm, thus making Satisfaction and The proportional relationship.

8. The range hood according to claim 6, characterized in that: The pressure drop of the airflow through the sound-absorbing material (52) is : In the above formula: in, The thickness of the sound-absorbing material (52) The value range is 10mm~50mm. For the corrected Reynolds number, The value range is 1000~10000. The equivalent average pore size of the sound-absorbing material (52) is given. The value range is 1µm to 100µm. For gas dynamic viscosity, The value range is 14.7~14.9×10. -6 m 2 / s, The porosity of the sound-absorbing material (52) is... The value range is 70% to 95%, thus making Satisfaction and The proportional relationship.

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