Lift-type range hood

Abstract

A lift-up range hood has a lower housing that moves up and down relative to an upper housing, and an air inlet that moves up and down relative to the lower housing. A fan is installed inside the upper housing. When both the lower housing and the air inlet are at their lowest positions, the height difference between the fan outlet and the lowest point of the air inlet is H1. When both the lower housing and the air inlet are at their highest positions, when the air inlet is completely inside the lower housing, the height difference between the fan outlet and the lowest point of the lower housing is H2, satisfying 0.55H1≤H2≤0.75H1. When part of the air inlet is inside the lower housing and the other part is outside the lower housing, the height difference between the fan outlet and the lowest point of the air inlet is H3, satisfying 0.6H1≤H3≤0.8H1. This range hood features a dual-stage lifting mechanism, resulting in a compact overall size when raised, minimizing space occupation. When lowered, the air inlet is closer to the smoke source, and the reduced negative pressure zone allows for faster smoke extraction. The fan can also be installed higher and further away from the listener's ears, thus reducing noise.

Description

Technical Field

[0001] This invention relates to the field of range hood technology, and in particular to a lift-type range hood. Background Technology

[0002] Range hoods have become an indispensable appliance in modern family kitchens. With their increasing usage, people are paying more and more attention to their smoke extraction efficiency and aesthetic appeal. Traditional top-mounted range hoods are bulky, making it easy for cooks to bump their heads. If the distance between the range hood's air inlet and the area where smoke is generated is large, the smoke's intake path is longer, increasing the extraction time and making it easier for smoke to escape during cooking. Lowering the installation height of the range hood and bringing the inlet as close to the smoke source as possible, while improving smoke extraction, results in a smaller cooking space, making it easier for the cook's head to accidentally hit the smoke hood. Furthermore, a lower installation height also affects visibility and the overall appearance of the kitchen. Therefore, lift-type range hoods were invented, where the smoke inlet can be raised and lowered; it lowers when the hood is on and rises when it is off. For example, the range hood disclosed in Chinese utility model patent No. 202222918682.7 (authorization announcement No. CN 218864291 U) includes a smoke collection chamber, a fan assembly and a lifting assembly. The fan assembly is set inside the smoke collection chamber, and the lifting assembly is connected to the smoke collection chamber. The lifting assembly can drive the smoke collection chamber to rise and fall. When the range hood is running, the lifting component lowers the smoke collection chamber below the cabinet, and the fan starts to extract the fumes. When the range hood is not running, the lifting component raises the smoke collection chamber into the cabinet, and the fan stops. This range hood has a single-stage lifting structure, with only one lifting component for the smoke collection chamber. The structure is relatively simple, and the positional constraints are limited. For a range hood with a two-stage lifting structure, it is necessary to ensure that each lifting component has sufficient downward travel to improve the smoke extraction effect by significantly lowering the negative pressure zone. It is also necessary to consider that when each lifting component is raised, the overall height of the unit should be reduced, resulting in a more compact and simpler structure, allowing for concealed installation. In conclusion, further improvements are needed to the existing lifting range hood structure. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a lift-type range hood that improves the smoke extraction effect by significantly lowering the negative pressure zone in the working state and has a low overall height in the non-working state, in light of the above-mentioned existing technology.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: The lifting range hood includes an upper box, a lower box, and an air inlet. The lower box is disposed on the upper box and can move up and down relative to the upper box. The air inlet is disposed on the lower box and can move up and down relative to the lower box. A fan is installed in the upper box. The invention is characterized by:

[0005] With both the lower housing and the air inlet at their lowest positions, the height difference between the fan outlet and the lowest point of the air inlet is H1.

[0006] With both the lower housing and the air inlet at their highest positions, when the air inlet is completely inside the lower housing, the height difference between the fan outlet and the lowest point of the lower housing is H2, and satisfies 0.55H1≤H2≤0.75H1; when part of the air inlet is inside the lower housing and the other part is outside the lower housing, the height difference between the fan outlet and the lowest point of the air inlet is H3, and satisfies 0.6H1≤H3≤0.8H1. With this configuration, when the air inlet is completely inside the lower housing, the height difference between the fan outlet and the lowest point of the lower housing is the overall height H2 of the range hood when it is not in use. When part of the air inlet is inside the lower housing and the other part is outside the lower housing, the height difference between the fan outlet and the lowest point of the air inlet is the overall height H3 of the range hood when it is not in use. Under the constraints of the above relationship, the overall height of the range hood when it is not in use can be almost 0.55 to 0.75 times or 0.6 to 0.8 times the overall height H1 when it is in use. This allows for a significant change in the overall height before and after raising and lowering, resulting in a more compact structure and smaller footprint when the range hood is not in use. With a smaller space and both the lower casing and the air inlet body lowered to their lowest positions, the negative pressure zone can be reduced even further, which helps improve the fume extraction effect. Furthermore, when not in use, there is a gap between the horizontal plane of the lowest point of the fan and the horizontal plane of the highest point of the air inlet body. This means that the air inlet body is always located below the fan, allowing the oil inside the fan to fall naturally into the air inlet body and then be discharged from the inner cavity of the range hood. This prevents oil from accumulating inside the fan or dripping into other places and failing to be discharged in time when the range hood is not in use. At this time, the air inlet body also acts as an oil guiding channel, and with the gap, the fan casing can guide the oil smoothly.

[0007] Preferably, the height of the fan is L1, and the height of the main body of the air inlet is L3. When both the lower housing and the air inlet are at their highest positions, at least 30% of the fan height L1 is located within the lower housing, and at least 80% of the air inlet's main body height L3 is located within the lower housing. This configuration ensures that, in the non-operating state, the lower housing can accommodate the fan and the main body of the air inlet, thereby reducing the overall height of the unit.

[0008] Further optimized, with the lower housing raised to its highest position, the height of the air inlet within the lower housing is L4, the height of the upper housing within the lower housing is L5, and the height of the lower housing is L6, satisfying L4 + L5 ≥ aL6, where a is 0.8, 0.85, 0.9, or 0.95. This configuration allows for full utilization of the lower housing's internal space to accommodate the upper housing and air inlet in non-operating states, thereby minimizing the overall height of the unit.

[0009] In order to limit the minimum descent stroke of the whole machine and enable the negative pressure zone to descend a sufficient distance, preferably, when the lower housing is lowered to the lowest position, the height of the fan is L1, the air inlet is provided with an air inlet, and the height from the bottom of the air inlet to the horizontal plane where the bottom of the fan is located is L2, satisfying: L2≥bL1, where b is 1.3, 1.4, 1.5 or 1.6.

[0010] Preferably, the upper and lower housings are nested together, with the outer wall of the upper housing at least partially nested within the lower housing. This structure, where the lower housing encloses the upper housing, allows oil to flow smoothly from the upper housing to the lower housing. In any state, the outer surface of the lower housing remains on the outermost edge of the entire unit, preventing oil contamination. Furthermore, it eliminates the need for excessive oil passages between the upper and lower housings, allowing the lower housing's front panel to be a single large panel for a clean and aesthetically pleasing appearance. On the other hand, fan noise, after exiting the fan frame, enters the lower housing's cavity, simulating a static pressure chamber. This improves the unsteady flow separation caused by inlet distortion, reducing pressure pulsation and improving sound quality. Noise can also be canceled out within the cavity using reactive silencing principles. Fan vibrations are transmitted to the lower housing, increasing the contact area between the lower housing and the wall, thus reducing the overall vibration frequency.

[0011] Preferably, an oil cup is installed at the bottom of the air inlet body, and when both the lower housing and the air inlet body are raised to their highest positions, the oil cup extends at least partially into the lower housing. This design allows the oil cup to be hidden when not in operation, resulting in a simpler and more aesthetically pleasing structure for the range hood.

[0012] In order to ensure that the air inlet can be completely concealed inside the lower housing when not in operation, the oil cup is fully inserted into the lower housing when both the lower housing and the air inlet are raised to their highest positions, so that the bottom of the oil cup is flush with or higher than the bottom of the lower housing.

[0013] To ensure the negative pressure zone can descend sufficiently during operation, with both the lower housing and the air inlet at their lowest positions, the top of the lower housing connects to the bottom of the upper housing, and the air inlet of the air inlet is fully exposed below the lower housing. This configuration brings the air inlet closer to the smoke source, improving the fume extraction effect.

[0014] Preferably, a horizontally arranged smoke baffle is provided at the bottom of the lower housing. This smoke baffle can effectively block smoke and reduce the escape of cooking fumes.

[0015] Further preferably, an upper guide plate is provided at the air inlet, located behind the smoke baffle, with the lowest edge of the upper guide plate lower than the bottom surface of the smoke baffle. This arrangement reduces the height of the air inlet, preventing a large amount of oil fumes from directly impacting the smoke baffle and thus avoiding the accumulation of excessive condensed oil on it.

[0016] In a further preferred embodiment, the upper guide plate extends upwards at an angle from its lowest edge toward the air inlet. This configuration, with the end of the upper guide plate bent, serves two purposes: firstly, it guides the flow of fumes, allowing them to enter the air inlet more smoothly along the bending direction; secondly, it acts as an oil guide groove.

[0017] Further preferably, the lower housing includes a first air inlet channel and a second air inlet channel that are interconnected. The first air inlet channel is located below and near the rear of the second air inlet channel. In all states except when the lower housing and the air inlet body are lowered to their lowest positions, the main body of the air inlet body is at least partially located within the first air inlet channel, and the fan is at least partially located within the second air inlet channel. This configuration allows the lower housing to accommodate the fan and the main body of the air inlet body in the non-operating state, thereby reducing the overall height of the unit.

[0018] Further optimized, the width W2 of the second air inlet channel in the front-to-back direction satisfies the same condition as the width W1 of the first air inlet channel in the front-to-back direction: W2 > W1. With this configuration, cooking fumes enter the second air inlet channel through the narrow first air inlet channel, and then enter the upper housing. Because the second air inlet channel is narrower, the cooking fume flow is faster, which can drive the external flow field to achieve faster airflow, giving the cooking fumes a greater backward velocity in the same amount of time, preventing the fumes from escaping. However, at the same time, the airflow will also be turbulent, causing uneven cooking fume flow velocity at the air inlet, affecting the fume extraction effect. The wider second air inlet channel is located downstream of the first air inlet channel. At this point, the larger volume of the second air inlet channel can create a highly efficient pressure stabilizing chamber, allowing the airflow to be buffered and stabilized within the pressure stabilizing chamber, ensuring that there is a basically uniform wind speed at the air inlet, avoiding the problem of fumes escaping from both sides of the range hood. Furthermore, the oil stains inside the upper chamber will drip into the lower chamber, and the problem of oil splashing and drifting is difficult to deal with, especially when there is a lot of condensed oil inside the fan system. The wide second air inlet channel can effectively reduce the wind speed, reduce the influence of airflow on the trajectory of oil droplets, and prevent oil droplets dripping from the volute from splashing.

[0019] Further optimized, the width W2 of the second air inlet channel in the front-to-back direction satisfies the same condition as the width W1 of the first air inlet channel in the front-to-back direction: W2 ≥ 1.5W1. With this configuration, the structures of the first and second air inlet channels form a variable cross-section air inlet channel, effectively blocking the direct transmission of fan system noise. By simulating the principle of reactive noise reduction, sound waves emitted from the fan are reflected multiple times within the wide second air inlet channel and thus canceled out. Therefore, a variable cross-section acoustic impedance is constructed, reducing the energy of sound propagating from the fan inlet to the range hood inlet. Additionally, this airflow buffer chamber, simulating a static pressure box, can improve the unsteady flow separation caused by inlet distortion, thereby reducing pressure pulsation and improving sound quality.

[0020] As a preferred embodiment of any of the above solutions, the lower housing moves up and down under the drive of the first drive mechanism, the air inlet moves up and down under the drive of the second drive mechanism, and the lower housing and the air inlet move up and down synchronously.

[0021] As a preferred embodiment of any of the above solutions, the lower housing and the air inlet move synchronously up and down under the drive of the same drive mechanism.

[0022] Compared with the prior art, the advantages of the present invention are as follows: This lifting range hood sets a height difference H1 between the fan outlet and the lowest point of the air inlet when both the lower housing and the air inlet are lowered to their lowest positions; and sets a height difference H2 between the fan outlet and the lowest point of the lower housing when both the lower housing and the air inlet are raised to their highest positions and the air inlet is completely inside the lower housing, satisfying 0.55H1≤H2≤0.75H1; and sets a height difference H3 between the fan outlet and the lowest point of the air inlet when the air inlet is partially inserted into the lower housing, satisfying 0.6H1≤H3≤0.8H1. Thus, through dual-stage lifting, the overall size of the machine is small in the raised state, reducing space occupation; in the lowered state, the air inlet is closer to the smoke source, the negative pressure zone is lowered, allowing for faster smoke intake; and the fan can be installed higher, further away from the listener's ear, thereby reducing noise. Furthermore, the overall size of the machine changes significantly between the two states. On the one hand, it can be concealed and raised, making the range hood occupy less space and more aesthetically pleasing. On the other hand, it lowers the negative pressure zone for fume extraction, improving the fume extraction effect. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a range hood according to an embodiment of the present invention (in a non-working state);

[0024] Figure 2 for Figure 1 The image shows a front view of the range hood.

[0025] Figure 3 for Figure 2 The image shows a sectional view of the range hood along line AA.

[0026] Figure 4 A schematic diagram of the structure of a range hood according to an embodiment of the invention (in working condition);

[0027] Figure 5 for Figure 4 The image shows a front view of the range hood.

[0028] Figure 6 for Figure 4 A three-dimensional sectional view of the range hood shown;

[0029] Figure 7 for Figure 5 The image shows a sectional view of the range hood along the BB direction.

[0030] Figure 8 This is a schematic diagram of the air inlet body according to an embodiment of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0032] The solution in this embodiment is implemented when the range hood is installed along a vertical wall, such as... Figures 1 to 7 As shown, the lift-type range hood of this embodiment includes an upper housing 1, a lower housing 2, and an air inlet 3. A fan 4 is installed inside the upper housing 1, and an oil cup 5 is installed at the bottom of the air inlet 3. The lower housing 2 is located on the upper housing 1 and can move up and down relative to the upper housing 1. The air inlet 3 is located on the lower housing 2 and can move up and down relative to the lower housing 2, thus realizing a two-stage lifting structure. The lower housing 2 and the air inlet 3 can move up and down synchronously under the drive of a single drive mechanism, or the lower housing 2 can move up and down under the drive of a first drive mechanism, and the air inlet 3 can move up and down under the drive of a second drive mechanism, but the lower housing 2 and the air inlet 3 still maintain synchronous up and down movement.

[0033] like Figure 7 As shown, with both the lower housing 2 and the air inlet 3 at their lowest positions, the height difference between the air outlet of the fan 4 and the lowest point of the air inlet 3 is H1. Figure 3As shown, in this embodiment, with both the lower housing 2 and the air inlet 3 at their highest positions, the air inlet 3 is completely located inside the lower housing 2. The height difference between the air outlet of the fan 4 and the lowest point of the lower housing 2 is H2, where H2 represents the overall height of the unit in the raised state. H1 and H2 satisfy 0.55H1≤H2≤0.75H1. If, with both the lower housing 2 and the air inlet 3 at their highest positions, there is a situation where part of the air inlet 3 is located inside the lower housing 2 and another part is located outside the lower housing 2, let the height difference between the air outlet of the fan 4 and the lowest point of the air inlet 3 be H3. If the height of the oil cup itself is ignored, this height difference H3 is the overall height of the unit in the raised state. In this case, H1 and H3 must satisfy: 0.6H1≤H3≤0.8H1. After the height differences H2 and H3 satisfy the above relationship, it means that the overall size of the machine is small when it is raised, reducing the space occupied. When it is lowered, the air inlet is closer to the smoke source, and the negative pressure zone is lowered, which can draw in the oil fumes faster. The overall size of the machine changes significantly in the two states. On the one hand, it can achieve concealed lifting and lowering, so that the range hood occupies less space and has a more beautiful appearance. On the other hand, it lowers the negative pressure zone for oil fume absorption, improving the oil fume absorption effect.

[0034] Assuming the height of fan 4 is L1, and in this embodiment the fan is a centrifugal fan, the height of fan 4 refers to the vertical distance between the horizontal plane where the lowest point of the volute is located and the horizontal plane where the highest point is located, when fan 4 is installed. Combined with... Figure 8 As shown, the air inlet 3 in this embodiment includes a main body 32 and extension arms 33 extending vertically upward on the left and right sides of the main body. The air inlet 31 of the air inlet 3 is located on the front side of the main body 32, and an air inlet channel is formed inside the main body 32. The extension arms 33 are used to cooperate with the lower housing 2 during the lifting and lowering process. On the one hand, they guide the lifting and lowering of the air inlet 3, and on the other hand, they prevent oil fumes from leaking between the air inlet 3 and the lower housing 2. Assuming that the height of the main body 32 is L3, when both the lower housing 2 and the air inlet 3 are raised to their highest positions, at least 30% of the height L1 of the fan 4 is located inside the lower housing 2, and at least 80% of the height L3 of the main body 32 of the air inlet 3 is located inside the lower housing 2. That is, in the non-working state, the lower housing 2 can accommodate the fan 4 and the main body 32 of the air inlet 3, thereby reducing the overall height of the unit and making it easier to hide the unit in a cabinet, improving its aesthetics.

[0035] like Figure 3 As shown, when the lower housing 2 and the air inlet 3 are raised to their highest positions, there are several different situations. One situation is that both the air inlet 3 and the oil cup 5 are completely inserted into the lower housing 2. For example, in this embodiment, the bottom of the oil cup 5 is flush with the bottom of the lower housing 2, or the bottom of the oil cup 5 is higher than the bottom of the lower housing 2. Another situation is that the air inlet 3 is completely inserted into the lower housing, while the bottom of the oil cup 5 is exposed at the bottom of the lower housing 2, or the entire oil cup 5 is exposed at the bottom of the lower housing 2. Yet another situation is that the bottom of the air inlet 3 and the entire oil cup 5 are exposed at the bottom of the lower housing 2.

[0036] Suppose the height of the air inlet body 3 inside the lower box body 2 is L4, the height of the upper box body 1 inside the lower box body 2 is L5, and the height of the lower box body 2 is L6, satisfying L4 + L5 ≥ aL6, where a is 0.8, 0.85, 0.9 or 0.95. Thus, in the non-working state, the internal space of the lower box body 2 can be fully utilized to accommodate the upper box body 1 and the air inlet body 3, thereby reducing the overall height of the machine as much as possible. In addition, it is also necessary to satisfy L4 + L5 < L6. In this way, in the non-working state, there is no overlapping part between the air inlet body 3 and the fan 4 in the vertical direction, and there is a certain gap, which is convenient for the oil liquid on the fan 4 to be introduced onto the air inlet body 3. It can be seen that the main body part 32 of the air inlet body is always located below the fan 4, so that the oil stain in the fan 4 can be guided into the air inlet body 3 along the natural falling trend, and then discharged from the inner cavity of the range hood, avoiding the accumulation of oil stain in the fan 4 or dripping and accumulating at other positions and being unable to be discharged in time when the range hood is not in use. At this time, the air inlet body 3 also acts as an oil guiding channel.

[0037] As Figure 7 shown, in this embodiment, when both the lower box body 2 and the air inlet body 3 are lowered to the lowest position, the top end of the lower box body 2 is connected to the bottom end of the upper box body 1, that is, the lower box body 2 reaches the maximum descending stroke. The main body part 32 of the air inlet body 3 extends downward as a whole out of the lower box body 2, the air inlet 31 is completely exposed, and the air inlet body 3 also reaches the maximum descending stroke. The height from the bottommost end of the air inlet 31 to the horizontal plane where the bottommost end of the fan 4 is located is L2, satisfying: L2 ≥ bL1, where b is 1.3, 1.4, 1.5 or 1.6. In this way, the minimum descending stroke of the whole machine can be limited, so that the negative pressure area can descend a sufficient distance, thereby improving the oil fume absorption effect.

[0038] The range hood of this embodiment adopts a structure in which the lower box body 2 wraps the upper box body 1, that is, the upper box body 1 and the lower box body 2 are nested and connected, and at least part of the outer wall surface of the upper box body 1 is nested inside the lower box body 2. Adopting the structure of the lower box body 2 wrapping the upper box body 1, on the one hand, it makes the oil stain flow from the upper box body 1 to the inside of the lower box body 2 along the trend. And in any state, the outer surface of the lower box body 2 is always on the outermost of the whole machine, so the outer surface of the lower box body 2 will not be polluted by oil stain, and there is no need for too many oil circuit designs between the upper box body 1 and the lower box body 2. The front panel of the lower box body 2 can be set as a whole large panel, making the appearance simple and beautiful. On the other hand, the noise of the fan 4 enters the accommodation cavity of the lower box body 2 after passing out of the fan frame, simulating a static pressure box, improving the unsteady flow separation caused by the distortion of the air inlet, thereby reducing the pressure pulsation, improving the sound quality, and the noise can also be offset in the accommodation cavity by using the principle of resistance sound absorption. The fan jitter is transmitted to the lower box body, and the contact area between the lower box body 2 and the wall surface increases, reducing the jitter frequency of the whole machine.

[0039] As Figure 6 and Figure 7As shown, with Figure 7 The direction indicated by the middle arrow C is backward. A horizontally arranged smoke baffle 6 is provided at the bottom of the lower housing 2, and an upper guide plate 7 is provided at the air inlet 31. The upper guide plate 7 is located behind the smoke baffle 6, and the lowest edge of the upper guide plate 7 is lower than the bottom surface of the smoke baffle 6. After setting the upper guide plate 7, on the one hand, the height of the air inlet can be reduced, and on the other hand, a large amount of oil smoke can be prevented from directly hitting the smoke baffle 6, thus preventing a large amount of condensed oil from condensing on the smoke baffle. In addition, in this embodiment, the upper guide plate 7 is inclined upward from the lowest edge and extends towards the air inlet to form a bent part 71. The bent part 71 serves two purposes: on the one hand, it guides the flow, making it easier for the oil smoke to enter the air inlet 3 more smoothly along the bent direction; on the other hand, it acts as an oil guide groove, guiding the oil on the upper guide plate 7 to the left and right sides.

[0040] like Figure 7 As shown, the lower housing 2 in this embodiment includes a first air inlet channel 21 and a second air inlet channel 22 that are fluidly connected to each other. The first air inlet channel 21 is located below and near the rear of the second air inlet channel 22. In all states except when the lower housing 2 and the air intake body 3 are lowered to their lowest position, the main body 32 of the air intake body 3 is at least partially located within the first air inlet channel 21, and the fan 4 is at least partially located within the second air inlet channel 22. The width W2 of the second air inlet channel 22 in the front-to-back direction and the width W1 of the first air inlet channel 21 in the front-to-back direction satisfy 1.1W1≤W2≤4W1. In this embodiment, both the first air inlet channel 21 and the second air inlet channel 22 are regular rectangular structures, meaning that W1 and W2 remain constant in their respective height directions. If they were irregular structures, then at any position in the height direction, the condition 1.1W1≤W2≤4W1 must also be satisfied.

[0041] With the aforementioned variable cross-section air inlet channel, the fumes enter the second air inlet channel 22 through the narrow first air inlet channel 21, and then enter the upper housing 1. Because the front and rear width of the first air inlet channel 21 is relatively narrow, the fumes flow velocity is fast, which can drive the external flow field to achieve faster airflow, giving the fumes a greater backward velocity in the same amount of time, preventing the fumes from escaping. However, at the same time, the airflow here will also be turbulent, causing the fumes flow velocity at the air inlet to be uneven, affecting the fume extraction effect. The wide second air inlet channel 22 is located downstream of the first air inlet channel 21. At this time, the second air inlet channel 22, due to its larger volume, can construct an efficient pressure stabilizing chamber, so that the airflow is buffered and stabilized in the pressure stabilizing chamber, ensuring that there is a basically the same wind speed at the air inlet, avoiding the problem of fumes escaping from both sides of the range hood. Furthermore, the oil stains inside the upper housing 1 will drip into the lower housing 2, and the problem of oil splashing and falling is difficult to deal with, especially when there is a lot of condensed oil inside the fan 4. The wide second air inlet channel 22 can effectively reduce the wind speed, reduce the influence of airflow on the trajectory of oil droplets, and prevent oil droplets dripping from the volute from splashing.

[0042] Furthermore, the variable cross-section air inlet channel effectively blocks the direct transmission of noise from the fan 4. By simulating the principle of reactive noise cancellation, the sound waves emitted from the fan 4 are reflected multiple times within the wide second air inlet channel 22 and thus canceled out. Therefore, a variable cross-section acoustic impedance is constructed to reduce the energy of sound propagating from the fan inlet to the range hood inlet. In addition, the airflow buffer chamber is constructed to simulate a static pressure box, which can improve the unsteady flow separation caused by inlet distortion, thereby reducing pressure pulsation and improving sound quality.

[0043] Furthermore, to increase the abrupt change in the flow channel width W2 of the second air inlet channel 22 and the flow channel width W1 of the first air inlet channel 21, and to ensure the buffering, pressure stabilization, noise reduction, and oil interception effects of the abrupt change in the variable cross-section channel on the airflow, when the lower housing and the air inlet body are both lowered to their lowest positions, W2 and W1 satisfy: 2W1≤W2≤3W1. Similarly, both the second air inlet channel 22 and the first air inlet channel 21 are regular rectangular structures, meaning that W1 and W2 remain unchanged in their respective height directions. If they are irregular structures, then at any position in the height direction, the following condition must also be met: 2W1≤W2≤3W1.

[0044] The specification and claims of this invention use terms indicating direction, such as "front," "rear," "upper," "lower," "left," "right," "side," "top," and "bottom," to describe various exemplary structural parts and elements of the invention. However, these terms are used herein merely for ease of explanation and are determined based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in this invention can be arranged in different orientations, these terms indicating direction are for illustrative purposes only and should not be considered as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0045] The term "fluid connectivity" as used in this invention refers to the spatial relationship between two components or parts, collectively referred to as the first part and the second part, meaning that 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 that allows fluid to flow through, or a combination of the above.

Claims

1. A liftable range hood, comprising an upper housing (1), a lower housing (2), and an air inlet (3), wherein the lower housing (2) is disposed on the upper housing (1) and is capable of lifting relative to the upper housing (1), the air inlet (3) is disposed on the lower housing (2) and is capable of lifting relative to the lower housing (2), and a fan (4) is installed inside the upper housing (1), characterized in that: With both the lower housing (2) and the air inlet (3) at their lowest positions, the height difference between the air outlet of the fan (4) and the lowest point of the air inlet (3) is H1. With both the lower housing (2) and the air inlet (3) at their highest positions, when the air inlet (3) is completely inside the lower housing (2), the height difference between the air outlet of the fan (4) and the lowest point of the lower housing (2) is H2, and satisfies 0.55H1≤H2≤0.75H1; when part of the air inlet (3) is inside the lower housing (2) and the other part is outside the lower housing (2), the height difference between the air outlet of the fan (4) and the lowest point of the air inlet (3) is H3, and satisfies 0.6H1≤H3≤0.8H1; The lower housing (2) includes a first air inlet channel (21) and a second air inlet channel (22) that are interconnected. The first air inlet channel (21) is located below the second air inlet channel (22) and close to the rear of the second air inlet channel (22). In any state other than when the lower housing (2) and the air inlet body (3) are lowered to their lowest position, the main body (32) of the air inlet body (3) is at least partially located in the first air inlet channel (21), and the fan (4) is at least partially located in the second air inlet channel (22).

2. The lifting range hood according to claim 1, characterized in that: The height of the fan (4) is L1, and the height of the main body (32) of the air inlet (3) is L3. When both the lower box (2) and the air inlet (3) are raised to their highest positions, at least 30% of the height L1 of the fan (4) is located inside the lower box (2), and at least 80% of the height L3 of the main body (32) of the air inlet (3) is located inside the lower box (2).

3. The lifting range hood according to claim 1, characterized in that: With the lower housing (2) raised to its highest position, the height of the air inlet (3) inside the lower housing (2) is L4, the height of the upper housing (1) inside the lower housing (2) is L5, and the height of the lower housing (2) is L6, satisfying L4+L5≥aL6, where a is 0.8, 0.85, 0.9, or 0.

95.

4. The lifting range hood according to claim 1, characterized in that: With the lower housing (2) at its lowest position, the height of the fan (4) is L1, the air inlet (3) is provided with an air inlet (31), and the height from the bottom of the air inlet (31) to the horizontal plane where the bottom of the fan (4) is located is L2, satisfying: L2≥bL1, where b is 1.3, 1.4, 1.5 or 1.

6.

5. The lifting range hood according to claim 1, characterized in that: The upper box (1) and the lower box (2) are nested together, and the outer wall of the upper box (1) is at least partially nested inside the lower box (2).

6. The lifting range hood according to claim 1, characterized in that: An oil cup (5) is installed at the bottom of the air inlet (3). When both the lower box (2) and the air inlet (3) are raised to their highest positions, the oil cup (5) extends at least partially into the lower box (2).

7. The lifting range hood according to claim 6, characterized in that: With both the lower housing (2) and the air inlet (3) at their highest positions, the oil cup (5) is fully inserted into the lower housing (2), so that the bottom of the oil cup (5) is flush with or higher than the bottom of the lower housing (2).

8. The lifting range hood according to claim 1, characterized in that: With both the lower housing (2) and the air inlet (3) lowered to their lowest positions, the top of the lower housing (2) is connected to the bottom of the upper housing (1), and the air inlet (31) of the air inlet (3) is fully exposed below the lower housing (2).

9. The lifting range hood according to claim 8, characterized in that: The bottom of the lower housing (2) is provided with a horizontally arranged smoke baffle (6).

10. The lifting range hood according to claim 9, characterized in that: An upper guide plate (7) is provided at the air inlet (31). The upper guide plate (7) is located on the rear side of the smoke baffle (6), and the lowest edge of the upper guide plate (7) is lower than the bottom surface of the smoke baffle (6).

11. The lifting range hood according to claim 10, characterized in that: The upper guide plate (7) extends upward from the lowest edge toward the air inlet (31).

12. The lifting range hood according to claim 1, characterized in that: The width W2 of the second air inlet channel (22) in the front-to-back direction and the width W1 of the first air inlet channel (21) in the front-to-back direction satisfy: W2 > W1.

13. The lifting range hood according to claim 12, characterized in that: The width W2 of the second air inlet channel (22) in the front-to-back direction and the width W1 of the first air inlet channel (21) in the front-to-back direction satisfy: W2≥1.5W1.

14. The lifting range hood according to any one of claims 1 to 13, characterized in that: The lower housing (2) moves up and down under the drive of the first drive mechanism, and the air inlet (3) moves up and down under the drive of the second drive mechanism, and the lower housing (2) and the air inlet (3) move up and down synchronously.

15. The lift-type range hood according to any one of claims 1 to 13, characterized in that: The lower housing (2) and the air inlet (3) move synchronously up and down under the drive of the same drive mechanism.

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