Filtering device of intelligent extractor hood, intelligent extractor hood and control method

Abstract

The invention discloses a filtering device of an intelligent extractor hood, the intelligent extractor hood and a control method, and the filtering device of the intelligent extractor hood is used for being arranged in an oil smoke channel of the extractor hood; the filtering device comprises an electret pre-charged filter screen and a filter element, the piezoelectric transducer assembly comprises a first piezoelectric transducer and a second piezoelectric transducer which are arranged on the two opposite sides in the oil smoke channel; the electret pre-charged filter screen and the piezoelectric transducer assembly are sequentially arranged from upstream to downstream along a lampblack flowing path.

Description

Technical Field

[0001] This invention relates to smart kitchen appliances, and more particularly to a filter device for a smart range hood, a smart range hood using the filter device, and a control method for the filter device of the smart range hood. Background Technology

[0002] Range hoods have become an indispensable kitchen appliance in modern homes. They operate on the principles of fluid dynamics, using a fan system installed inside to draw in and exhaust cooking fumes, and a filter to remove some of the grease particles.

[0003] Traditional range hoods typically use a metal filter combined with a centrifugal fan impeller to filter cooking fumes. However, this method can only separate large oil particles, and is largely ineffective against submicron-sized oil fume particles, such as PM10 or even PM2.5. In recent years, however, users have become increasingly concerned about the hazards and pollution caused by submicron-sized particles, such as PM10 or even PM2.5.

[0004] Some solutions employing high-voltage electrostatics can improve the filtration capacity of these submicron particles to a certain extent. For example, Chinese Patent Application No. 202420927804.5 discloses an oil adsorption module for use in range hoods. The module includes an ionization zone component, which comprises: an ionization zone support with a first receiving groove; and an ionization plate disposed within the first receiving groove. The ionization plate is provided with several discharge tips and several first high-voltage conductive rods corresponding to the discharge tips, so as to electrically connect each discharge tip. The discharge tips and the first high-voltage conductive rods are integrated into the ionization plate and integrally formed with it.

[0005] However, this type of filtration device, which operates on high voltage for extended periods, poses a risk of sparking and has high energy consumption. Since energy consumption is a core performance indicator for range hoods, many consumers will not choose models with excessively high energy consumption, thus impacting the direction of technological development. Therefore, further improvements are needed. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a filtration device for an intelligent range hood that improves the filtration capacity of submicron-level oil fume particles, such as PM10 and even PM2.5, with low power consumption.

[0007] The second technical problem to be solved by the present invention is to provide an intelligent range hood that uses the above-mentioned filtration device.

[0008] The third technical problem to be solved by the present invention is to provide a control method for the filtration device of the above-mentioned intelligent range hood.

[0009] The technical solution adopted by the present invention to solve the first technical problem mentioned above is: a filter device for an intelligent range hood, used to be installed in the oil fume duct of the range hood; characterized in that: The filtration device includes: Electret pre-charged filter; and A piezoelectric transducer assembly, comprising a first piezoelectric transducer and a second piezoelectric transducer arranged on opposite sides within an oil fume duct; Along the oil fume flow path, the electret pre-charged filter and the piezoelectric transducer assembly are arranged sequentially from upstream to downstream.

[0010] By setting up an electret pre-charged filter, when oil fumes pass through, the oil fume particles become charged due to field polarization. The charged fibers then capture the particles using Coulomb force and induction force. This filtration mechanism not only relies on physical filtration but also adds electrostatic adsorption, enhancing the particle migration rate in the acoustic field, thereby improving the filtration efficiency for submicron particles. Combined with a piezoelectric transducer assembly downstream, a standing wave field with a 180° phase difference can be formed. The acoustic radiation force drives charged oil droplets to converge at the standing wave nodes, maximizing the acoustic radiation force and adaptively adapting to changes in oil fume composition, improving aggregation efficiency and enhancing filtration capacity. Through the synergistic effect of the electret pre-charged filter and the ultrasonic standing wave field, combining electrostatic force and acoustic radiation force, the filtration capacity for submicron-level oil fume particles below PM10 and even around PM2.5 is improved, increasing the interception and filtration efficiency from 90%~92% for ordinary mechanical filters to 98%.

[0011] Furthermore, to facilitate adjustment of the voltage of the electret pre-charged filter and the frequency of the piezoelectric transducer assembly based on the oil fume particles, the filtration device further includes:

[0012] Oil fume sensors are used to detect the concentration of oil fumes and the median particle size of oil fume particles; and

[0013] A potentiometer is used to detect the surface voltage of an electret precharged filter.

[0014] Furthermore, the fume sensor comprises two sensors arranged along the fume flow path, one upstream of the electret precharged filter and the other downstream of the piezoelectric transducer assembly. This enables feedback control.

[0015] Preferably, the electret precharged filter is a multi-layer honeycomb electret filter with an equivalent diameter of 2-8 mm.

[0016] Preferably, the electret precharged filter is a filter made of corona-polarized polypropylene.

[0017] The technical solution adopted by the present invention to solve the second technical problem mentioned above is as follows: an intelligent range hood, including an air inlet body and a main controller, wherein an oil fume channel is formed in the air inlet body, characterized in that: a filter device of the range hood as described above is provided in the oil fume channel, and each component of the filter device is electrically connected to the main controller.

[0018] The technical solution adopted by the present invention to solve the third technical problem mentioned above is: a control method for the filter device of an intelligent range hood, wherein the range hood includes an air inlet body and a main controller, and an oil fume channel is formed in the air inlet body;

[0019] Its characteristic is that: the fume duct is equipped with a filter device of the range hood as described above, and each component of the filter device is electrically connected to the main controller;

[0020] The control method includes the following steps: 1) Turn on the range hood. If a shutdown signal is received, turn off all transducers. If not, proceed to step 2). 2) Real-time data is collected by a fume sensor located upstream of the electret precharged filter. The data includes the fume concentration C and the median particle size D of the fume particles. 50 ; 3) Determine the collected real-time oil fume concentration C and median particle size D. 50 If the preset threshold is exceeded, proceed to step 4); otherwise, maintain the current frequency parameters of the piezoelectric transducer assembly and the voltage parameters of the electret precharge filter. 4) Based on the real-time detected oil fume concentration C and the median particle size D of the oil fume particles. 50 Calculate frequency , The frequency of the piezoelectric transducer assembly is adjusted to the calculated frequency. ; Calculate voltage ,in As a gain parameter, the voltage applied to the electret precharge filter is adjusted to the calculated voltage. Then proceed to step 5); 5) Determine whether the acoustic field phases of the two piezoelectric transducers are synchronized. If they are, update the frequency and voltage control parameters and return to step 2); if not, trigger phase calibration.

[0021] Furthermore, to facilitate the detection of the effects after frequency and voltage adjustments, in step 5), a real-time oil fume concentration C and median particle size D of the oil fume are collected by an oil fume sensor located downstream of the piezoelectric transducer assembly. 50 To determine the effectiveness of frequency and voltage adjustments.

[0022] Compared with existing technologies, the advantages of this invention are as follows: By setting an electret pre-charged filter, when oil fumes pass through, the oil fume particles become charged due to field polarization. The captured particles are achieved by utilizing the Coulomb force and inductive force of the charged fibers on the particles. This filtration mechanism not only relies on physical filtration but also adds electrostatic adsorption, enhancing the particle migration rate in the acoustic field, thereby improving the filtration efficiency for submicron particles. In conjunction with the piezoelectric transducer assembly located downstream, a standing wave field with a phase difference of 180° can be formed. The acoustic radiation force drives the charged oil droplets to gather at the standing wave nodes of the standing wave field, thereby maximizing the acoustic radiation force, adaptively and dynamically adapting to changes in oil fume composition, improving aggregation efficiency, and strengthening filtration capacity. Through the synergistic effect of the electret pre-charged filter and the ultrasonic standing wave field, combined with electrostatic force and acoustic radiation force, the filtration capacity for submicron-level oil fume particles within PM10 and even around PM2.5 is improved, increasing the interception and filtration efficiency from 90%~92% of ordinary mechanical filters to 98%. Attached Figure Description

[0023] Figure 1 This is a front view of the range hood installed according to an embodiment of the present invention; Figure 2 This is a side view of the range hood installed according to an embodiment of the present invention (large air volume for steaming and cooking); Figure 3 This is a cross-sectional view of a range hood according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the filtration device of a range hood according to an embodiment of the present invention; Figure 5 This is a control principle diagram of a range hood according to an embodiment of the present invention; Figure 6 This is a control flowchart of a range hood according to an embodiment of the present invention. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0025] 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.

[0026] See Figure 1 and Figure 2 A range hood includes an air inlet body 1 and a fan frame 2. The fan frame 2 houses a fan (not shown). An oil fume channel 11 is formed within the air inlet body 1, located upstream of the fan along the oil fume flow path. Alternatively, when the range hood has different forms, such as ceiling-mounted or top-mounted, the oil fume channel 11 may be formed in a component other than the air inlet body 1, as long as it is located upstream of the fan.

[0027] The range hood also includes a filter device installed within the fume duct 11. This filter device is a combined filter module that solves the problems of low interception efficiency and high energy consumption of traditional mechanical filters for submicron-sized particles by using dynamically polarized electret material pre-charged oil droplets in synergy with ultrasonic standing wave fields. The filter device is located downstream of the fume inlet 12 formed on the air inlet body 1.

[0028] Specifically, the filtration device includes an oil fume sensor 31, a potentiometer 32, an electret precharged filter 33, and a piezoelectric transducer assembly (including a first piezoelectric transducer 34 and a second piezoelectric transducer 35). Along the oil fume flow path, the electret precharged filter 33 and the piezoelectric transducer assembly are arranged sequentially from upstream to downstream. In this embodiment, they are arranged sequentially from bottom to top.

[0029] Among them, the oil fume sensor 31 can be similar to a laser scattering sensor, which can measure the oil fume particle concentration C and median particle size distribution D. 50 The value of (median particle size), D 50 This indicates that in a particle group, 50% of the particles have a diameter smaller than this value, and 50% have a diameter larger than this value. For example, the D value in cooking fumes... 50 Typically between 0.3 and 5 μm, depending on the cooking method: low-temperature cooking (steaming, boiling, stewing): D50 ≈ 1~5μm (mainly large droplets); High-temperature cooking (frying, stir-frying): D 50 ≈ 0.3~1μm (high proportion of small particles). Therefore, different cooking methods may result in different median particle sizes, and enhanced filtration, especially the acoustic standing wave method, needs to consider D. 50 The node spacing of a standing acoustic wave is determined by its wavelength. The wavelength must match the target particle size. When the particle diameter At that time, the sound radiation force is at its maximum ( At this point, the aggregation efficiency is optimal. Therefore, we choose D. 50 As the target particle size, it ensures that the sound field covers the region with the highest proportion of particles in the oil fume, achieving globally optimized filtration. Preferably, there are two oil fume sensors 31, which are respectively arranged upstream of the electret precharged filter 33 (inlet of the filter device) and downstream of the piezoelectric transducer assembly (outlet of the filter device).

[0030] Potentiometer 32 is a surface potentiometer, mounted on the surface of the electret precharge filter 33 (non-contact type, range 0~10kV, accuracy ±5%). It detects the charge density corresponding to the voltage. (The correlation between voltage and charge density is based on existing technology) When it is less than a certain value, such as Time-triggered power replenishment.

[0031] The electret pre-charged filter 33 preferably employs a multi-layered honeycomb electret filter. Electret is a functional material capable of maintaining a static charge or polarized state for a long period, possessing characteristics similar to permanent magnets but acting on an electric field. Through specific processing, electrets achieve a stable internal charge distribution, forming a persistent surface electric field. They are widely used in sensors, transducers, air purification, and other fields. Typical electrets (such as polarized polypropylene PP) pre-store charge through corona discharge or thermal polarization processes, forming a permanent electrostatic field on their surface (charge decay half-life > 5 years). Under normal operating conditions, the electret pre-charged filter 33 maintains its electrostatic field and intercepts charged particles without a power supply. Compared to traditional electrostatic adsorption (requiring continuous high-voltage power), electrets only consume energy during polarization, resulting in zero energy consumption during daily operation. Pre-charging enhances the acoustic field force.

[0032] In this embodiment, the electret precharged filter 33 can be made of corona-polarized polypropylene with an initial surface charge density > The equivalent diameter of the honeycomb mesh is 2-8 mm. The working principle of the electret pre-charged filter 33 is based on electrostatically enhanced fiber filtration, that is, using the Coulomb force and inductive force of charged fibers on particles to capture particles. This filtration mechanism not only relies on physical filtration, but also adds electrostatic adsorption, thereby improving the filtration efficiency for submicron particles. When oil fumes pass through, the oil fume particles become charged due to field polarization.

[0033] The electret pre-charged filter 33 requires online dynamic repolarization because: ① Oil fumes may contain water vapor or conductive particles such as salt, which adhere to the electret filter material, causing surface charge loss. Periodic repolarization replenishment is necessary (e.g., once a month, each time <1 minute). The polarization voltage (0-10kV) can be dynamically adjusted during installation to replenish or repolarize; ② When the oil fume concentration suddenly increases (e.g., during stir-frying), temporarily increasing the polarization voltage can enhance charge density, prevent electric field saturation, and improve the filtration capacity for high-concentration oil fumes. The polarization voltage can be used... This is the gain coefficient calibrated in the laboratory. To achieve dynamic adaptive increase of the temporary polarization voltage when the oil fume concentration suddenly increases, the polarization voltage is increased to maintain the real-time charge density on the electret surface. To avoid charge saturation or loss, it reduces voltage and saves energy at low concentrations, enabling on-demand power supply.

[0034] Intermittent power supply can be used to supplement polarization: voltage is applied briefly through a high-voltage generator only when needed, such as after power-on or when the stir-fry button is pressed (on-demand polarization). After polarization, the circuit is disconnected, returning to the power-free state. This achieves: 99% power-free operation: relying on a pre-stored electrostatic field; 1% active adjustment: power is applied only briefly when the charge is insufficient (annual cumulative energy consumption <0.1kWh). It is more energy-efficient than ordinary electrostatic filters and more effective than traditional electret filters. Timely replenishment makes it more durable and suitable for a wide range of concentrations. See Table 1.

[0035]

[0036] Table 1: Comparison of filters in the prior art and the present invention

[0037] The first piezoelectric transducer 34 and the second piezoelectric transducer 35 are arranged on opposite sides within the fume duct 11, such as Figure 3 The diagram shows a symmetrical arrangement on both sides. Each piezoelectric transducer has a frequency of 20-100kHz and a power of 50W, capable of forming a standing wave field with a 180° phase difference. Acoustic radiation force drives charged oil droplets to converge at position 36 of the standing wave node in the standing wave field. The frequency of the piezoelectric transducer assembly... Where c is the speed of sound, such as 340 m / s, and the median particle diameter D can be matched by dynamically adjusting the frequency f. 50 Thus maximizing sound radiation power , Based on particle diameter, it adaptively and dynamically adapts to changes in oil fume composition, improving agglomeration efficiency and enhancing filtration capabilities.

[0038] See Figure 5 The range hood of this invention is an intelligent range hood, which may include a main controller 4 to achieve intelligent detection and control. The main controller 4 has a processor, and the fan drive module 44 (fan not shown, can be in any existing form and installation position) and various components of the filter device are electrically connected to the main controller 4. In addition, the main controller 4 may also be electrically connected to a switch module 41, a storage module 42, and a lamp module 43, which are the same as in the prior art.

[0039] See Figure 6 The control method of the filtration device of the present invention is implemented by the main controller 4 for calculation and judgment. Specifically, the control method includes the following steps:

[0040] 1) When the range hood is turned on, if a shutdown signal is received, all transducers will be turned off and the system will shut down. If not, the system will be initialized and the fume sensor 31 will perform a self-test. If a fault is detected, an alarm will be triggered, non-core modules will be shut down, and the range hood will enter normal operating mode. If normal, proceed to step 2). Non-core modules refer to modules of the range hood other than the fan, such as the Wi-Fi module and various sensors.

[0041] 2) Real-time data, including oil fume concentration C and median particle size D, is collected by the oil fume sensor 31 at the inlet. 50 ;

[0042] 3) Determine whether C or D is correct. 50 If the concentration exceeds a preset threshold, proceed to step 4; otherwise, maintain the current parameters. The typical threshold value for concentration C is 10 mg / m³. Voltage regulation is triggered when the concentration at the filter inlet (where the fumes enter the filter) > 10 mg / m³. To avoid electric field saturation, for example, when stir-frying, the concentration of carbon (C) can reach 50-100 mg / m³, requiring the voltage to be increased to 6-10 kV; D 50 The threshold can be selected as: D 50 ∈[0.3 μm, 5 μm], when D 50 When <0.3μm: f max Set to 567kHz (sound field limit), when D 50 When >5μm: f min Set to 34kHz (which can be handled by mechanical filtering); triggering an alarm if the frequency exceeds the range (indicating sensor malfunction or extreme operating conditions).

[0043] 4) Based on the detected oil fume concentration C and the median particle size D of the oil fume particles.50 Calculate frequency , The frequency of the piezoelectric transducer assembly is adjusted to the calculated frequency. ; Calculate voltage The voltage to be applied to the electret precharge filter 33 is adjusted to the calculated voltage. Then proceed to step 5);

[0044] 5) Perform feedback detection to detect the oil fume concentration C and the median particle size D at the filter outlet (the location where the oil fume leaves the filter, where an oil fume sensor 31 can also be installed). 50 It can be compared with its respective preset threshold to determine whether the parameter adjustment is effective;

[0045] Determine whether the acoustic field phases of the two piezoelectric transducers are synchronized. If they are, update the control parameters (frequency and voltage, after which each transducer will operate at this frequency, and the electret precharge filter 33 can be charged as needed according to this voltage), and return to step 2); if not, trigger phase calibration.

[0046] In this step, determining whether the sound field phase is synchronized can usually be achieved by directly calling a function from the two piezoelectric transducers to obtain the phase difference. ,if This indicates synchronization; it can also be obtained through the following calculation:

[0047] ① Signal acquisition: Acquire the drive current of the two piezoelectric transducers: , Piezoelectric signals inside the acoustic cavities of the two piezoelectric transducers: ② Phase difference calculation: , where T is the period of the signal;

[0048] The synchronization conditions are the same as above, that is... The threshold for out-of-step: ;

[0049] If they are not synchronized, phase calibration needs to be triggered. The calibration mechanism can be: fine-tuning the drive signal delay of one of the piezoelectric transducers. : ,like, , hour, ;

[0050] The aforementioned methods for determining whether the acoustic field phase of a piezoelectric transducer is synchronized and for phase calibration are existing technologies in the field of piezoelectric transducers.

Claims

1. A filter device for an intelligent range hood, used to be installed in the fume duct (11) of the range hood; characterized in that: The filtration device includes: Electret precharged filter (33); and A piezoelectric transducer assembly comprising a first piezoelectric transducer (34) and a second piezoelectric transducer (35) arranged on opposite sides within an oil fume duct (11); Along the oil fume flow path, the electret precharged filter (33) and the piezoelectric transducer assembly are arranged sequentially from upstream to downstream.

2. The filtration device of the intelligent range hood according to claim 1, characterized in that: The filtration device further includes: A fume sensor (31) is used to detect the concentration of oil fumes and the median particle size of oil fume particles; and A potentiometer (32) is used to detect the surface voltage of the electret precharged filter (33).

3. The filtration device of the intelligent range hood according to claim 2, characterized in that: The fume sensor (31) has two components along the fume flow path, one of which is located upstream of the electret precharged filter (33) and the other is located downstream of the piezoelectric transducer assembly.

4. The filtration device of the intelligent range hood according to claim 1 or 2, characterized in that: The electret precharged filter (33) is a multi-layer honeycomb electret filter with an equivalent diameter of 2~8mm.

5. The filtration device of the intelligent range hood according to claim 4, characterized in that: The electret precharged filter (33) is a filter made of corona-polarized polypropylene.

6. A smart range hood, comprising an air inlet (1) and a main controller (4), wherein an oil fume channel (11) is formed within the air inlet (1), characterized in that: The fume duct (11) is provided with a filter device of the range hood as described in any one of claims 1 to 5, and each component of the filter device is electrically connected to the main controller (4).

7. A control method for the filter device of an intelligent range hood, wherein the intelligent range hood includes an air inlet (1) and a main controller (4), and an oil fume channel (11) is formed in the air inlet (1); Its features are: The oil fume channel (11) is equipped with a filter device of the intelligent range hood as described in claim 3, and each component of the filter device is electrically connected to the main controller (4); The control method includes the following steps: 1) Turn on the range hood. If a shutdown signal is received, turn off all transducers. If not, proceed to step 2). 2) Real-time data is collected by an oil fume sensor (31) located upstream of the electret precharged filter (33), the data including oil fume concentration C and median particle size D of the oil fume particles. 50 ; 3) Determine the collected real-time oil fume concentration C and median particle size D. 50 If the preset threshold is exceeded, proceed to step 4); otherwise, maintain the frequency parameters of the current piezoelectric transducer assembly and the voltage parameters of the electret precharge filter (33). 4) Based on the real-time detected oil fume concentration C and the median particle size D of the oil fume particles. 50 Calculate frequency , The frequency of the piezoelectric transducer assembly is adjusted to the calculated frequency. ; Calculate voltage ,in As a gain parameter, the voltage applied to the electret precharge filter (33) is adjusted to the calculated voltage. Then proceed to step 5); 5) Determine whether the acoustic field phases of the two piezoelectric transducers are synchronized. If they are, update the frequency and voltage control parameters and return to step 2); if not, trigger phase calibration.

8. The control method for the filter device of the intelligent range hood according to claim 7, characterized in that: In step 5), the real-time oil fume concentration C and the median particle size D of the oil fume particles are also collected by an oil fume sensor (31) located downstream of the piezoelectric transducer assembly. 50 To determine the effectiveness of frequency and voltage adjustments.

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