Range hood and control method thereof

Abstract

The present invention relates to a range hood and a control method thereof, the range hood comprising: a housing having an air inlet; a rotary filter screen driven by a drive motor and rotatably disposed at the air inlet; a protective cover disposed in the housing, downstream of the rotary filter screen along the smoke flow path, the protective cover having an arc-shaped guide surface arched toward the side of the rotary filter screen; a drive motor disposed on the side of the protective cover away from the arc-shaped guide surface, the output shaft of the drive motor passing through the protective cover and connected to the rotary filter screen. This can effectively prevent smoke from invading the drive motor and extend the service life of the drive motor. On the other hand, the protective cover has an arched arc-shaped guide surface on the side facing the rotary filter screen (i.e., toward the direction of incoming airflow), which can better guide the smoke, reduce the flow resistance of the smoke, and ensure the smoke extraction effect.

Description

Technical Field

[0001] The present invention relates to the technical field of kitchen appliances, and in particular to a range hood and a control method thereof. Background Art

[0002] A range hood is a kitchen appliance that purifies the kitchen environment. Fumes produced during cooking easily adhere to the range hood's oil deflector, filter, hood cavity, and fan. If not cleaned promptly, grease builds up over time, reducing the range hood's fan's effectiveness in extracting fumes.

[0003] Static filters and electrostatic adsorption are commonly used for oil fume purification and filtration. Static filters are primarily installed at the air inlet of the range hood. By increasing the density of the filter holes, the probability of physical collision between oil smoke and the filter is increased, thereby improving the grease separation ability. However, after long-term use, the grease attached to the filter tends to clog the filter holes, increasing the ventilation resistance. Electrostatic adsorption uses a high-voltage electrostatic field to ionize the gas passing between the electrodes, causing it to adsorb to the electrodes and achieve the purpose of purifying oil fumes. However, after long-term use, the accumulated grease on the plates is difficult to clean. Grease itself is flammable and will burn when exposed to open flames or excessive temperatures, posing a fire hazard.

[0004] To improve the oil fume purification effect, existing range hoods also have a rotating filter installed at the air inlet that can be driven by negative pressure airflow or an independent motor. The oil fume pollutants physically collide with the rotating filter, intercepting oil droplets and throwing them out under the action of centrifugal force, thereby improving the oil separation effect of the range hood. For example, Chinese utility model patent application number CN202020162275.6 discloses a rotating filter, a filter assembly, and a range hood. The rotating filter is used in a range hood and includes a filter body and a rotating fan blade; the rotating fan blade includes a connecting sleeve and a plurality of blades arranged at intervals along the rotating circumference of the connecting sleeve, and the plurality of blades are all inclined toward the same side; the filter body is connected to the leeward side of the rotating fan blade. This rotating filter is driven by the upward suction air generated by the range hood. As the oil smoke passes through the rotating filter, it continuously cuts the oil smoke and intercepts the oil droplets in the oil smoke. After the rotating filter intercepts the oil smoke, the oil droplets on the rotating filter are flung out in all directions due to the centrifugal force generated by the rotation. This cycle can improve the separation of oil and fat from the oil smoke. However, because the rotating filter is driven by the upward suction air generated by the range hood, the rotation speed cannot be precisely controlled, and it cannot effectively adapt to various cooking conditions and achieve targeted oil smoke filtration effects.

[0005] For example, the Chinese utility model patent application number CN201922435084.2 discloses a smoke intake structure for a fume extraction device, including a smoke collection hood for connecting to a negative pressure device, the negative pressure device can form a negative pressure in the smoke collection chamber in the smoke collection hood, the smoke collection hood is provided with a smoke inlet for feeding smoke into the smoke collection chamber, a stretching cylinder is provided in the smoke inlet, a drive motor is fixed in the stretching cylinder, the drive motor is connected to a shielding mesh disk that is covered in the stretching cylinder and located on the smoke inlet, and the drive motor can drive the shielding mesh disk to rotate on the smoke inlet. The shielding mesh disk is controlled by an independently arranged motor. Although the speed of the shielding mesh disk can be accurately adjusted to a state that matches the cooking conditions, since the motor used to drive the shielding mesh disk to rotate is exposed to the oil smoke, the sealing requirements of the motor are very high, and the fluid performance of the motor surface is poor. Its vertical placement at the air inlet affects the oil smoke extraction effect.

[0006] Therefore, existing range hoods also need further improvement. Summary of the Invention

[0007] The first technical problem to be solved by the present invention is to provide a range hood that can reduce the invasion of oil smoke on the driving motor used to drive the filter to rotate and can smoothly guide the smoke in response to the current status of the existing technology.

[0008] The second technical problem to be solved by the present invention is to provide a control method for a range hood that has good oil fume purification effect and can achieve self-cleaning in response to the current status of the existing technology.

[0009] The technical solution adopted by the present invention to solve the first technical problem is: a range hood comprising:

[0010] a housing having an air inlet;

[0011] A rotary filter screen is driven by a driving motor and is arranged at the air inlet;

[0012] a protective cover disposed in the housing and located downstream of the rotary filter along the smoke flow path, the protective cover having an arc-shaped guide surface arched toward one side of the rotary filter;

[0013] The driving motor is arranged on a side of the protective cover away from the arc-shaped guide surface, and the output shaft of the driving motor passes through the protective cover and is connected to the rotary filter.

[0014] In order to further reduce the contact between oil smoke and the drive motor, and avoid the impact of the opening on the top of the protective cover on the air flow, and reduce noise problems, the protective cover has an opening on the side away from the air inlet, and a cover is provided at the opening. The cover and the protective cover together define a closed installation chamber, and the drive motor is arranged in the installation chamber.

[0015] As improvements, it also includes:

[0016] The cold air circulation device includes a refrigerator for cooling gas, the gas outlet of the refrigerator is connected to the installation chamber through a first gas pipe, thereby transporting the air flow cooled by the refrigerator into the installation chamber, and the gas inlet of the refrigerator is connected to the installation chamber through a second gas pipe, thereby transporting the gas in the installation chamber to the refrigerator.

[0017] Bringing cold air into the installation chamber can not only cool the drive motor, but also cool the outer surface of the protective cover. After the outer surface of the protective cover is cooled, it can better condense oil droplets, water droplets and other particles. It will also cool the passing oil smoke, reducing the impact of the oil smoke on downstream components.

[0018] As an improvement, a deflector is further provided in the casing, which has a first port connected to the air inlet of the casing and a second port away from the air inlet and connected to the inner wall of the casing. The diameter of the deflector gradually increases from the first port to the second port, and a second flow duct for smoke to pass through is formed between the arc-shaped deflecting surface of the protective cover and the inner wall of the deflector. The cross-sectional area of the second flow duct first decreases and then increases along the direction of smoke flow. The design of the deflector can smoothly guide the oil that is thrown off during the rotation of the rotating filter and the oil dripping from the inner wall of the casing and the fan system downward, thereby facilitating the collection of the oil. On the other hand, the structural design of the cross-sectional area of the second flow duct first decreases and then increases along the direction of smoke flow, which also corresponds to the speed of the smoke flowing through the air inlet (that is, the location of the rotating filter) being slowed down. When the rotating speed of the rotating filter is constant, the rotating filter has a longer contact time with the oil smoke particles in the smoke, thereby improving the oil smoke purification effect.

[0019] To reduce the escape of cooking fumes, the air inlet is located at the bottom of the housing. A smoke shield is also provided on the housing, corresponding to a position below the air inlet. A first flow duct is formed between the smoke shield and the housing, allowing external smoke to enter the air inlet. The smoke shield acts as a negative pressure drainage mechanism, allowing smoke to crawl along the bottom surface of the smoke shield due to the Coanda effect, thereby reducing the escape of cooking fumes.

[0020] In order to further slow down the flue gas flow rate at the air inlet and effectively improve the oil fume purification effect, the smoke baffle is raised in the direction away from the air inlet in the area corresponding to the air inlet, so that the cross-sectional area of the first flow duct gradually increases along the direction of flue gas flow.

[0021] In order to facilitate the collection of oil accumulated on the smoke shield, an oil cup extending in the left-right direction is further provided on the rear side of the smoke shield.

[0022] In order to further improve the oil fume purification effect, at least the arc-shaped guide surface of the rotary filter and the protective cover are made of metal; and further comprising:

[0023] The electrostatic generating device has a positive electrode connected to the arc-shaped guide surface of the protective cover, and a negative electrode connected to the rotating filter.

[0024] After the electrostatic generating device is started, a high-voltage electrostatic field is formed between the rotating filter and the curved guide surface of the protective cover. The oil fume particles in the flue gas are adsorbed to the surface of the curved guide surface under the action of the electric field force, thereby improving the oil fume purification effect.

[0025] Since the electrostatic adsorption effect is better when there are more oil fume particles in the flue gas (such as in stir-frying mode), and the electrostatic adsorption effect is not obvious when there are fewer oil fume particles in the flue gas (such as in steaming mode), in order to selectively turn on the electrostatic generating device according to the actual cooking conditions, a humidity sensor for detecting the water vapor content in the flue gas is also included. The humidity sensor is electrically connected to the control system of the range hood, so that the control system controls the opening and closing of the electrostatic generating device according to the flue gas humidity signal transmitted by the humidity sensor.

[0026] In order to achieve self-cleaning of the curved guide surface of the protective cover, the drive motor is electrically connected to the control system of the range hood, so that the control system controls the speed of the drive motor to alternately increase and decrease when the humidity value of the flue gas delivered by the humidity sensor is greater than the set humidity value.

[0027] When the humidity value of the flue gas transmitted by the humidity sensor is greater than the set humidity value, it can be considered that the current cooking mode is the steaming mode, and the flue gas component is mainly water vapor. Therefore, the water vapor in the flue gas can be used to clean the surface of the arc-shaped guide surface (to absorb and accumulate oil stains). Specifically, the rotation speed of the driving motor alternately increases and decreases, which further improves the cleaning effect of water vapor on the protective cover and the rotating filter. For example, when the rotation speed of the driving motor rotates to the minimum, the resistance of the airflow through the rotating filter is small and the flow rate is large, which can effectively flush the arc-shaped guide surface of the protective cover and peel off the oil stains adsorbed on the arc-shaped guide surface; and when the rotation speed of the driving motor rotates to the maximum, the resistance of the airflow through the rotating filter is large and the flow rate is small. The high-speed rotation process of the rotating filter can intercept most of the steam, and the intercepted steam can be cleaned by the rotating filter itself in the process of being thrown away by the filter. During this process, oil and water droplets peeled off the curved guide surface also drip downward. Once they land on the high-speed rotating filter below, they are thrown in all directions by the centrifugal force of the rotating filter. The deflector then guides the water downward and collects in the oil cup behind the smoke shield below. This alternating speed of the drive motor ensures efficient self-cleaning of the rotating filter and the curved guide surface of the protective cover.

[0028] In order to further improve the self-cleaning effect of the rotating filter and the curved guide surface of the protective cover, a fan system is also included in the casing. The fan system is electrically connected to the control system of the range hood, so that when the humidity value of the flue gas delivered by the humidity sensor is greater than the set humidity value, the control system controls the rotational speed of the fan system to alternately decrease and increase. That is, when the rotational speed of the drive motor is at the maximum value, the rotational speed of the fan system is the minimum, and when the rotational speed of the drive motor is at the minimum value, the rotational speed of the fan system is the maximum.

[0029] When the speed of the fan system increases, the speed of the rotating filter decreases. During this process, due to the reduction in the resistance of the rotating filter, the suction force of the fan increases, the steam sucked into the range hood cavity gradually increases, and the kinetic energy increases. The air with high-temperature steam is used to perform periodic pulse cleaning on the inner cavity of the range hood and the curved guide surface of the protective cover.

[0030] When the fan system speed decreases, the rotating filter speed increases, the fan suction force decreases, the rotating filter resistance increases, the steam sucked into the range hood cavity decreases, and the kinetic energy decreases. At this time, the smoke (mainly water vapor) is sucked into the range hood smoke inlet. Because the rotating filter is working at a high speed, it can intercept most of the steam in the process of throwing it away. The intercepted steam will be thrown away with the filter to the surrounding deflector, and the rotating filter can self-clean during this process.

[0031] The technical solution adopted by the present invention to solve the second technical problem is: a control method for a range hood, comprising the following steps:

[0032] S1, start the range hood;

[0033] S2, the fan system starts to operate, and the driving motor drives the rotating filter to rotate;

[0034] S3. The humidity sensor detects and obtains the humidity value in the flue gas, and determines whether the humidity value in the current flue gas is less than the set humidity value. If yes, proceed to step S4; if not, proceed to step S5;

[0035] S4. The current smoke component is mainly oil smoke, the electrostatic generating device is turned on, the control system controls the drive motor to drive the rotary filter to rotate at a set speed, and then returns to step S3;

[0036] S5. When the current flue gas composition is primarily water vapor, the electrostatic generating device is turned off, and the control system controls the speed of the drive motor to alternately increase and decrease. Simultaneously, the speed of the drive fan system is controlled to alternately decrease and increase. That is, when the speed of the drive motor is at its maximum, the speed of the fan system is at its minimum. When the speed of the drive motor is at its minimum, the speed of the fan system is at its maximum. After the set time, the process proceeds to step S6.

[0037] S6. The driving motor drives the rotating filter to rotate at the set speed, and the fan system also runs at the set speed.

[0038] Compared with the prior art, the advantages of the present invention are as follows: the driving motor for driving the rotating filter is arranged on the side of the protective cover away from the air inlet, thereby effectively avoiding the invasion of smoke on the driving motor and extending the service life of the driving motor. On the other hand, the protective cover has an arched arc-shaped guide surface on the side facing the rotating filter (that is, facing the direction of airflow), which can better guide the smoke, reduce the flow resistance of the smoke, and ensure the oil fume absorption effect. In the preferred embodiment, by providing an electrostatic generating device, a high-voltage electrostatic field is formed between the rotating filter and the arc-shaped guide surface of the protective cover, and the oil fume particles in the smoke are adsorbed to the surface of the arc-shaped guide surface under the action of the electric field force, further improving the oil fume purification effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic diagram of the three-dimensional structure of a range hood according to an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of the three-dimensional structure of the range hood according to an embodiment of the present invention without the smoke shield;

[0041] Figure 3 for Figure 2Schematic diagram of the three-dimensional structure after omitting the rotating filter;

[0042] Figure 4 A vertical cross-sectional view of a range hood according to an embodiment of the present invention taken along the left-right direction;

[0043] Figure 5 A vertical cross-sectional view of the range hood according to an embodiment of the present invention taken along the front-to-back direction;

[0044] Figure 6 Flowchart of a control method for a range hood according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0046] In the present specification and claims, directional terms such as "front," "back," "up," "down," "left," "right," "side," "top," and "bottom" are used to describe various exemplary structural parts and components of the present invention. However, these terms are used herein for convenience of description only and are based on the exemplary orientations shown in the accompanying drawings. Because the embodiments disclosed herein can be arranged in various orientations, these directional terms are intended for illustrative purposes only and should not be construed as limiting. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0047] See also Figures 1-6 A range hood includes a housing 10, a fan system 13, a rotary filter 20, and a smoke baffle 70. The housing 10 includes a fan frame 11 and a smoke hood 12 disposed at the bottom of the fan frame 11. The bottom of the smoke hood 12 is concave to form a smoke collection chamber 121. An air inlet 120 is defined in the top center of the smoke collection chamber 121 and communicates with the inner cavity of the fan frame 11. The fan system 13 is disposed within the inner cavity of the fan frame 11 to provide negative pressure for extracting and exhausting oil fumes.

[0048] The fan system 13 is generally a centrifugal fan, such as Figure 4 The centrifugal fan is shown to be placed horizontally, that is, the air suction port of the volute of the centrifugal fan is arranged downward.

[0049] See also Figure 4 The smoke shield 70 is typically located below the air inlet 120 of the smoke hood 12 and is often detachably connected to the bottom of the smoke hood 12 using a snap or snap connection. An oil cup 71 extending horizontally is integrally formed on the rear side of the smoke shield 70. The smoke shield 70 is generally inclined downward from front to back. As a result, oil (oil-water mixture) dripping onto the smoke shield 70 collects in the oil cup 71 on the rear side under the action of its own gravity.

[0050] A first flow duct 51 is formed between the smoke baffle 70 and the inner wall of the smoke collecting chamber 121 of the smoke hood 12, for external smoke to enter the air inlet 120. More specifically, the middle portion of the smoke baffle 70 (i.e., the area corresponding to the air inlet 120) is convex downward, so that the cross-sectional area of the first flow duct 51 gradually increases along the flow direction of the smoke. Taking into account the need for the smoke baffle 70 to guide the oil backward into the oil cup 71, the cross section of the smoke baffle 70 (i.e., the vertical cross section in the left and right directions) is roughly V-shaped. The structural design of this smoke baffle 70 allows the smoke to flow slowly at the air inlet 120 during its flow along the first flow duct 51, thereby increasing the contact time between the rotating filter 20 and the oil fume particles in the smoke and improving the oil fume purification effect.

[0051] The setting of the V-shaped smoke baffle 70 can also play a role in negative pressure drainage, that is, the smoke can crawl along the bottom surface of the smoke baffle 70 to the left and right walls under the Coanda effect, and be quickly captured at the left and right entrances of the first overflow air duct 51, and sucked into the first overflow air duct 51, thereby reducing the escape of oil smoke.

[0052] The rotating filter 20 is disposed at the air inlet 120 of the smoke collecting hood 12 , and specifically is placed flat at the air inlet 120 . The rotating filter 20 is disc-shaped as a whole, and can rotate around its own axis under the drive of the driving motor 21 .

[0053] To facilitate the installation of the drive motor 21 and to guide the flue gas at the air inlet 120, a protective cover 30 is provided within the inner cavity of the fan frame 11, adjacent to the air inlet 120. The left and right sides of the protective cover 30 are connected to the sidewalls of the inner cavity of the fan frame 11 via mounting brackets. The protective cover 30 is a hemispherical cover that arches toward the air inlet 120. The arched outer wall of the protective cover 30 forms a curved guide surface 31. The top opening of the protective cover 30 is covered by a lid 32, which also features an upwardly protruding convex surface 320 that diverts oil dripping from above (e.g., the fan system 13). The lid 32 and protective cover 30, when combined, form an installation chamber 33 for mounting the drive motor 21. The installation chamber 33 is a closed structure that prevents external flue gas from entering, protecting the drive motor 21 from oil smoke and extending its service life.

[0054] The drive motor 21 is mounted at the bottom of the inner cavity of the protective cover 30, i.e., at the center of the bottom wall of the protective cover 30, and is secured by screws. The output shaft of the drive motor 21 passes through the protective cover 30 and connects to the center of the rotating filter 20. This allows the drive motor 21 to rotate the rotating filter 20. The drive motor 21 is electrically connected to the range hood's control system. When the range hood's fan system 13 is switched to the corresponding gear, the drive motor 21 also operates at the corresponding speed, thereby achieving a targeted oil fume purification effect. For example, when the oil smoke concentration is high, the fan system 13 operates at a high gear, and the drive motor 21 also drives the rotating filter 20 to rotate at a high speed; conversely, when the oil smoke concentration is low, the fan system 13 operates at a low gear, and the drive motor 21 also drives the rotating filter 20 to rotate at a low speed. The above-mentioned drive motor 21 switches with the gear of the range hood mainly considering the working condition where the smoke is mainly oil smoke. For the working condition where the smoke is mainly water vapor, the speed adjustment of the drive motor 21 and the fan system 13 is specifically described below.

[0055] A deflector 40 is also provided in the fan frame 11. The deflector 40 is basically cylindrical and placed vertically. The bottom port of the deflector 40 is a first port 41, and its diameter is basically the same as the air inlet 120 of the smoke hood 12. The top port of the deflector 40 is a second port 42, and its diameter is larger than the first port 41, so that it can be connected and fixed to the inner wall of the fan frame 11. Figure 4 It can be seen that the diameter of the air guide cover 40 gradually increases from its first port 41 to the second port 42, and there is a gap between the arc-shaped guide surface 31 of the protective cover 30 and the inner wall of the air guide cover 40. The gap is the second flow duct 52 for the smoke to pass through. The cross-sectional area of the second flow duct 52 first decreases and then increases along the direction of smoke flow.

[0056] In the process of intercepting grease and other particulate matter in the flue gas by the rotating filter 20, the speed and direction of the pollutants are not uniform and very complex. The speed and direction of the pollutants after being intercepted and impacted are uncontrollable, and some of them may even gain an upward speed (toward the inside of the wind frame 11). At the same time, due to the negative pressure of the centrifugal fan, the pollutants will be further driven into the cavity of the wind frame 11. As a result, most of the pollutants will still be sucked into the inner cavity of the wind frame 11 by this filtering method of the dynamic rotating filter 20, and the filtering effect of the oil smoke is limited. In order to solve the above problems, in this embodiment, the entire overflow duct formed by the corresponding connection of the second overflow duct 52 and the first overflow duct 51 (the first overflow duct 51 is formed between the smoke baffle 70 and the smoke hood 12) forms a pressure reduction zone with an increased cross-sectional area at the air inlet 120 (that is, the location of the rotary filter 20), that is, the flow velocity of the flue gas is slowed down at the air inlet 120 during the entire flow process from the outside into the inside of the fan frame 11. This ensures that when the rotating filter 20 rotates at a certain speed, the rotary filter 20 and the oil fume particles in the flue gas can have sufficient time to contact, further improving the oil fume purification effect. Even if some of the oil fume particles pass through the rotary filter 20 with the flue gas, they will most likely be adsorbed on the arc-shaped guide surface 31 of the protective cover 30, thereby further reducing the amount of oil stains attached to the downstream fan system 13. For details on the flow path of the flue gas, see Figure 4 The hollow arrow shown in .

[0057] The oil thrown off during the rotation of the rotary filter 20 and the oil dripping on the inner wall of the casing 10 and the fan system 13 will also be smoothly guided downward through the deflector 40, dripping onto the back of the smoke baffle 70, and then collected in the oil cup 71 on the rear side of the smoke baffle 70.

[0058] See also Figure 4 The range hood also includes a cold air circulation device, which can cool the interior of the installation chamber 33 and the protective cover 30 itself. Specifically, the cold air circulation device includes a refrigerator 60 for cooling the gas. The refrigerator 60 can adopt a conventional air refrigerator 60 in the prior art, which has a gas inlet and a gas outlet. The gas outlet of the refrigerator 60 is connected to the installation chamber 33 through a first gas pipe 61, thereby transporting the airflow cooled by the refrigerator 60 into the installation chamber 33. The gas inlet of the refrigerator 60 is connected to the installation chamber 33 through a second gas pipe 62, thereby transporting the gas in the installation chamber 33 to the refrigerator 60 for re-cooling, thereby forming a cold air circulation loop. Bringing cold air into the installation chamber 33 can not only cool the drive motor 21, but also cool the outer surface of the protective cover 30. After the outer surface of the protective cover 30 is cooled, it can better condense oil droplets, water droplets and other particles, and also cool the passing flue gas, reducing the impact of oil smoke on downstream components.

[0059] Continue to see Figure 4 The range hood of this embodiment further includes an electrostatic generator 80. The rotating filter 20 is a metal component, and the side of the protective cover 30 where the curved guide surface 31 is located is also a metal component. The positive electrode of the electrostatic generator 80 is electrically connected to the curved guide surface 31 of the protective cover 30 via a brush 81, while the negative electrode is also electrically connected to the outer edge of the rotating filter 20 via the brush 81. When the electrostatic generator 80 is activated, a high-voltage electrostatic field is formed between the rotating filter 20 and the curved guide surface 31 of the protective cover 30. The electric field forces the oil fume particles in the smoke that have been initially filtered by the rotating filter 20 to be attracted to the surface of the curved guide surface 31, thereby enhancing the oil fume purification effect.

[0060] In cooking conditions with high levels of oily smoke particles (e.g., stir-frying), electrostatic adsorption is more effective. However, in cooking conditions with low levels of oily smoke particles (e.g., steaming), the electrostatic adsorption effect is less pronounced. To selectively activate the electrostatic generator 80 based on the actual cooking conditions, the generator 80 is electrically connected to a humidity sensor (not shown) on the range hood. The humidity sensor detects the water vapor content in the smoke. The control system activates and deactivates the electrostatic generator 80 based on the smoke humidity signal from the humidity sensor. This automatically activates the generator in stir-frying mode, where high levels of oily smoke particles are present, and deactivates it in steaming mode, where high levels of water vapor are present.

[0061] When purifying oil fumes by electrostatic adsorption, a large amount of oil will accumulate on the curved guide surface 31 of the protective cover 30 after long-term use, which will not only affect the electrostatic adsorption effect, but also affect the flow effect of the airflow in the second overflow air duct 52, resulting in noise problems. For this reason, the curved guide surface 31 of the protective cover 30 needs to be cleaned in time. In this embodiment, the curved guide surface 31 of the protective cover 30 is cleaned by using a large amount of water vapor in the flue gas when the range hood is switched to the cooking mode.

[0062] When the humidity sensor detects that the smoke humidity is greater than a set humidity value, the current cooking mode is considered to be steaming mode, and the smoke is primarily composed of water vapor. Therefore, the water vapor in the smoke can be used to clean the surface of the curved guide surface 31 (to absorb accumulated oil stains). The humidity sensor, drive motor 21, and fan system 13 of this embodiment are all electrically connected to the range hood's control system. When the humidity sensor detects that the smoke humidity is greater than a set humidity value, the control system controls the speed of the drive motor 21 to alternately increase and decrease, while also controlling the speed of the fan system 13 to alternately increase and decrease. Specifically, when the speed of the drive motor 21 is at its maximum, the speed of the fan system 13 is correspondingly adjusted to its minimum. When the speed of the drive motor 21 is at its minimum, the speed of the fan system 13 is correspondingly adjusted to its maximum.

[0063] When the speed of the fan system 13 increases and the speed of the drive motor 21 rotates to the minimum, the resistance of the airflow through the rotating filter 20 is small and the flow rate is large, which can effectively flush the curved guide surface 31 of the protective cover 30 and remove the oil stains adsorbed on the curved guide surface 31. When the speed of the fan system 13 decreases and the speed of the drive motor 21 rotates to the maximum, the resistance of the airflow through the rotary filter 20 is large and the flow rate is small. The high-speed rotation of the rotary filter 20 can intercept most of the rising steam, and the intercepted steam can be cleaned by the rotary filter 20 itself in the process of being thrown away to the surroundings; at the same time, due to the reduction of the negative pressure of the fan system 13, the oil and water droplets peeled off from the arc-shaped guide surface 31 of the protective cover 30 will also drip downwards during this process. After falling on the high-speed rotating rotary filter 20 below, they will also be thrown around under the centrifugal action of the high-speed rotating rotary filter 20, and then drip downwards under the guiding action of the guide cover 40 and gather in the oil cup 71 on the rear side of the smoke baffle 70 below, thereby preventing the dripping oil from accumulating on the back of the rotary filter 20. The rotational speeds of the drive motor 21 and the fan system 13 are alternating in this way, so that efficient self-cleaning of the rotating filter 20 and the curved guide surface 31 of the protective cover 30 can be achieved without the need for additional spraying devices to clean the rotating filter 20 and the curved guide surface 31 of the protective cover 30, thereby simplifying the structure of the oil fume purification device of the range hood and reducing production costs.

[0064] See also Figure 6 A control method for a range hood comprises the following steps:

[0065] S1, start the range hood;

[0066] S2, the fan system 13 starts to operate, and the driving motor 21 drives the rotating filter 20 to rotate;

[0067] S3. The humidity sensor detects and obtains the humidity value in the flue gas, and determines whether it is less than the set humidity value. If yes, proceed to step S4; if not, proceed to step S5;

[0068] S4: The current flue gas is mainly composed of oil smoke. The electrostatic generating device 80 and the cold air circulation device are turned on. The control system controls the drive motor 21 to rotate the rotary filter 20 at a set speed (adapted to the oil smoke concentration value, which can be detected by the oil smoke concentration sensor). At the same time, the cold air circulation device is started, and then the process returns to step S3.

[0069] S5. The current flue gas composition is mainly water vapor. The electrostatic generating device 80 and the cold air circulation device are both turned off. The control system controls the speed of the drive motor 21 to alternately increase and decrease. At the same time, the speed of the drive fan system 13 is controlled to alternately decrease and increase. That is, when the speed of the drive motor 21 is at the maximum value, the speed of the fan system 13 is at the minimum value. When the speed of the drive motor 21 is at the minimum value, the speed of the fan system 13 is at the maximum value. After running for a set time, the process proceeds to step S6.

[0070] S6. The driving motor 21 drives the rotary filter 20 to rotate at a set speed (the "set speed" is preset in the control system of the range hood), and the fan system 13 also runs at a set speed (the "set speed" is preset in the control system of the range hood).

Claims

1. A range hood comprising: The housing (10) has an air inlet (120); A rotary filter (20) is driven by a driving motor (21) to rotate and is disposed at the air inlet (120); It is characterized by also including: A protective cover (30) is provided in the housing (10) and is located downstream of the rotary filter (20) along the smoke flow path. The protective cover (30) has an arc-shaped guide surface (31) that arches toward one side of the rotary filter (20); The driving motor (21) is arranged on a side of the protective cover (30) away from the arc-shaped guide surface (31), and an output shaft of the driving motor (21) passes through the protective cover (30) and is connected to the rotary filter (20); The protective cover (30) has an opening on a side away from the air inlet (120), and a cover (32) is provided at the opening. The cover (32) and the protective cover (30) together enclose a closed installation chamber (33), and the drive motor (21) is provided in the installation chamber (33); Also includes: A cold air circulation device includes a refrigerator (60) for cooling gas, wherein the gas outlet of the refrigerator (60) is connected to the installation chamber (33) through a first gas pipe (61), thereby transporting the air flow cooled by the refrigerator (60) into the installation chamber (33), and the gas inlet of the refrigerator (60) is connected to the installation chamber (33) through a second gas pipe (62), thereby transporting the gas in the installation chamber (33) into the refrigerator (60).

2. The range hood according to claim 1, characterized in that: A deflector (40) is further provided in the casing (10), the deflector (40) having a first port (41) connected to the air inlet (120) of the casing (10) and a second port (42) away from the air inlet (120) and connected to the inner wall of the casing (10), the aperture of the deflector (40) gradually increasing from the first port (41) to the second port (42), a second flow duct (52) for smoke to pass through is formed between the arc-shaped guide surface (31) of the protective cover (30) and the inner wall of the deflector (40), and the cross-sectional area of the second flow duct (52) first decreases and then increases along the flow direction of the smoke.

3. The range hood according to claim 2, characterized in that: The air inlet (120) is located at the bottom of the housing (10), and the housing (10) is further provided with a smoke shield (70) at a position corresponding to the position below the air inlet (120). A first flow duct (51) is formed between the smoke shield (70) and the housing (10) for external smoke to enter the air inlet (120).

4. The range hood according to claim 3, characterized in that: The smoke baffle (70) is convex in a region corresponding to the air inlet (120) in a direction away from the air inlet (120), so that the cross-sectional area of the first flow passage (51) gradually increases along the direction of smoke flow.

5. The range hood according to claim 3, characterized in that: An oil cup (71) extending in the left-right direction is further provided on the rear side of the smoke baffle (70).

6. The range hood according to claim 1, characterized in that: At least the arc-shaped flow guide surface (31) of the rotary filter (20) and the protective cover (30) are made of metal; and further comprising: The electrostatic generating device (80) has a positive electrode connected to the arc-shaped guide surface (31) of the protective cover (30), and a negative electrode connected to the rotating filter (20).

7. The range hood according to claim 6, characterized in that: It also includes a humidity sensor for detecting the water vapor content in the smoke, and the humidity sensor is electrically connected to the control system of the range hood, so that the control system controls the opening and closing of the electrostatic generating device (80) according to the smoke humidity signal transmitted by the humidity sensor.

8. The range hood according to claim 7, characterized in that: The drive motor (21) is electrically connected to the control system of the range hood, so that the control system controls the rotation speed of the drive motor (21) to alternately increase and decrease when the humidity value of the smoke delivered by the humidity sensor is greater than a set humidity value.

9. The range hood according to claim 8, characterized in that: The range hood further comprises a fan system (13) disposed in the housing (10), wherein the fan system (13) is electrically connected to a control system of the range hood, so that when the humidity value of the smoke delivered by the humidity sensor is greater than a set humidity value, the control system controls the rotation speed of the fan system (13) to alternately decrease and increase, that is, when the rotation speed of the drive motor (21) is at its maximum value, the rotation speed of the fan system (13) is at its minimum value, and when the rotation speed of the drive motor (21) is at its minimum value, the rotation speed of the fan system (13) is at its maximum value.

10. A range hood control method according to claim 9, characterized in that The following steps are involved: S1, start the range hood; S2, the fan system (13) is running, and the driving motor (21) drives the rotating filter (20) to rotate; S3. The humidity sensor detects and obtains the humidity value in the flue gas. The control system determines whether the humidity value in the current flue gas is less than the set humidity value. If yes, it proceeds to step S4; if not, it proceeds to step S5. S4, the current smoke components are mainly oil smoke, the electrostatic generating device (80) is turned on, the control system controls the driving motor (21) to drive the rotating filter (20) to rotate at a set speed, and then returns to step S3; S5. The current smoke components are mainly water vapor, the electrostatic generating device (80) is turned off, and the control system controls the rotation speed of the driving motor (21) to alternately increase and decrease. At the same time, the rotation speed of the driving fan system (13) is controlled to alternately decrease and increase. That is, when the rotation speed of the driving motor (21) is at the maximum value, the rotation speed of the fan system (13) is at the minimum value. When the rotation speed of the driving motor (21) is at the minimum value, the rotation speed of the fan system (13) is at the maximum value. After running for a set time, the process proceeds to step S6. S6, the driving motor (21) drives the rotary filter (20) to rotate at a set speed, and the fan system (13) also operates at a set speed.

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