A range hood

Abstract

This utility model discloses a range hood, including a centrifugal fan. The centrifugal fan includes a volute and an impeller disposed within the volute. The impeller includes blades. The range hood also includes a detection module, which includes a transmitting module capable of emitting electromagnetic waves at a frequency in the terahertz band to the blades at corresponding positions and a receiving module capable of receiving the electromagnetic waves reflected by the blades. The range hood also includes a processing component capable of determining the thickness of the oil film accumulated on the blades based on the energy of the electromagnetic waves received by the receiving module and determining the type of grease accumulated on the blades based on the frequency band of the electromagnetic waves received by the receiving module. The processing component is electrically connected to the detection module.

Description

Technical Field

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

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

[0003] After prolonged use, a large amount of oil and dust accumulates inside the casing of a range hood, especially in the fan system, where oil and dust buildup becomes severe. For example, a range hood disclosed in Chinese patent application number 202310919004.9 has a vertically arranged fan. When the impeller stops rotating, one side is at its lowest point. Accumulated oil and grease gather along the blade structure and drip down to this lowest position, resulting in more oil accumulation at this point than in other areas. This also means that the impeller's dynamic balance is disrupted, causing the entire unit to vibrate and requiring cleaning and maintenance (similar problems exist with other layouts).

[0004] Most range hoods currently use accumulated impeller running time to remind users to maintain their appliances. However, firstly, different users have different cooking habits, resulting in significant differences in grease buildup on the impeller blades. In areas like Sichuan and Chongqing, grease buildup might be severe before the maintenance reminder time is due, while in areas with lighter diets, no obvious contamination might be visible even after several cycles. Therefore, relying solely on accumulated time for reminders is prone to misjudgment. If users find no obvious dirt after in-home cleaning or automatic cleaning, they may feel the reminders are unpredictable, leading to a poor user experience.

[0005] Secondly, the position of the impeller during and after operation results in different areas having varying levels of oil contact and accumulation. Some areas have thicker oil, while others have thinner oil. Time-based reminders cannot account for the actual oil accumulation in different areas. In some areas, the coating has peeled off, while in others, it remains unclean.

[0006] Furthermore, relying solely on time-based reminders is prone to misjudgment. This can easily lead to situations where users find no obvious dirt after on-site or automatic cleaning, resulting in feelings that the manufacturer's judgment is uncontrollable, unintelligent, overcharged, and provides a poor user experience.

[0007] Finally, the types of oils (zoo oil and vegetable oil, which are rich in saturated and unsaturated fats respectively, are related to health, and dietary recommendations are necessary as a direction for the development of smart home appliances); and different types of cleaning agents and cleaning methods are needed to remove them more effectively. Existing manufacturers generally cannot identify the type of oil and recommend cleaning agents based on the degree of dirt, and their intelligence and cleaning ability are relatively poor. Utility Model Content

[0008] The technical problem to be solved by this utility model is to provide a range hood that improves the accuracy of pollution detection, addressing the shortcomings of the existing technology.

[0009] The technical solution adopted by this utility model to solve the above-mentioned technical problem is as follows: a range hood, comprising a centrifugal fan, wherein the centrifugal fan comprises a volute and an impeller disposed within the volute, and the impeller comprises blades; characterized in that:

[0010] The range hood also includes a detection module, which includes a transmitting module capable of emitting electromagnetic waves with a frequency in the terahertz band to the blades at the corresponding positions, and a receiving module capable of receiving the electromagnetic waves reflected by the blades.

[0011] The range hood also includes a processing component that can determine the thickness of the oil film accumulated on the blades based on the electromagnetic wave energy received by the receiving module and the type of grease accumulated on the blades based on the frequency band of the electromagnetic waves received by the receiving module. The processing component is electrically connected to the detection module.

[0012] By installing a detection module capable of transmitting and receiving frequencies in the wide-band terahertz range of 0.1–1.2 THz, the thickness of the oil film accumulated on the blades can be calculated based on the reflected energy. Furthermore, the specific absorption of organic matter by terahertz waves can be used to identify the type of oil, facilitating subsequent recommendations for healthy cooking and cleaning methods. Using this detection module, online monitoring of oil film thickness with an accuracy of 0.05 mm (more than 5 times higher than traditional infrared methods) can be achieved, unaffected by impeller speed (applicable to 0–1500 rpm conditions), effectively improving the accuracy of contamination detection.

[0013] To facilitate the installation of the detection module, the detection module is installed on the annular wall of the volute, and the annular wall has an opening corresponding to the position of the detection module.

[0014] To reduce the impact of oil contamination on the detection module, the volute has a volute tongue. On the projection along the axis of the impeller, the projection point of the axis is O, the projection point of the end of the volute tongue is M1, and the projection point of the center of the contact between the detection module and the volute is M2. The angle formed between the line connecting M1 and O and the line connecting M2 and O is α, and the value of α is in the range of [20-60°].

[0015] Furthermore, the range hood also includes a cleaning device, which includes a water tank for storing cleaning media, a heating or steam generating module for heating or vaporizing the cleaning media in the water tank, and a spray arm for receiving the cleaning media processed by the heating or steam generating module to clean the centrifugal fan.

[0016] Furthermore, the heating or steam generating module and the spray arm are fluidly connected by a first conduit. The spray arm is located between the wall of the volute and the impeller, and nozzles are provided on the spray arm, thereby facilitating the cleaning of the blades.

[0017] Furthermore, the spray arm is also equipped with a brush head, which can brush away the softened oil stains on the blades.

[0018] Furthermore, the cleaning device also includes a drive mechanism for driving the spray arm to rotate in a direction parallel to the axis of the centrifugal fan. This facilitates expanding the cleaning range and allows the spray arm to rotate when cleaning is not required, thus preventing the accumulation of oil or blockage caused by prolonged exposure to grease in a fumes-filled channel.

[0019] Furthermore, the range hood also includes an electrical box, which includes a power board and a radiator for heat dissipation of the power board;

[0020] The cleaning device includes a three-way valve with one inlet and two outlets. The water tank is connected to one inlet of the three-way valve via a second conduit, and the heating or steam generating module is connected to one outlet of the three-way valve. The second conduit passes through a radiator. This allows the heat from the radiator to preheat the cleaning medium, reducing energy consumption, and also improves the radiator's heat dissipation effect.

[0021] Furthermore, another outlet of the three-way valve is connected to the water tank via a third conduit, which facilitates the recovery of the cleaning medium.

[0022] Preferably, the radiator is finned, and the second conduit bends through each fin of the radiator, thereby improving heat exchange efficiency.

[0023] Compared with existing technologies, the advantages of this invention are as follows: By installing a detection module capable of transmitting and receiving frequencies in the wide-band terahertz range (e.g., 0.1–1.2 THz), the thickness of the oil film accumulated on the blades can be calculated based on the reflected energy. Furthermore, the specific absorption of organic matter by terahertz waves can be used to identify the type of oil, facilitating subsequent recommendations for healthy cooking and cleaning methods. When using this detection module, online monitoring of oil film thickness with an accuracy of 0.05 mm can be achieved (more than 5 times higher than traditional infrared methods), unaffected by impeller speed (applicable to 0–1500 rpm conditions), effectively improving the accuracy of contamination detection. Attached Figure Description

[0024] Figure 1 This is a side view of the range hood installed according to an embodiment of the present utility model;

[0025] Figure 2 This is a cross-sectional view (left-right section) of the range hood according to an embodiment of the present utility model;

[0026] Figure 3 This is a cross-sectional view (front and rear section) of the range hood according to an embodiment of the present utility model;

[0027] Figure 4 This is a schematic diagram of the centrifugal fan and its cleaning device of the range hood according to an embodiment of the present utility model;

[0028] Figure 5 This is a schematic diagram of the centrifugal fan and its cleaning device of the range hood according to an embodiment of the present invention (and...). Figure 4 (Different perspectives);

[0029] Figure 6 This is a schematic diagram of part of the electrical box and cleaning device of the range hood according to an embodiment of the present utility model;

[0030] Figure 7 This is a cross-sectional view of the fan system of the range hood according to an embodiment of the present utility model;

[0031] Figure 8 This is a graph showing the relationship between frequency and the absorption value of electromagnetic waves by grease in an embodiment of this utility model.

[0032] Figure 9 This is a control principle diagram of the range hood according to an embodiment of the present invention. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0034] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They 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 utility model 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.

[0035] See Figures 1 to 7A range hood includes a centrifugal fan 1, which comprises a volute 11, an impeller 12 disposed within the volute 11, and a motor 13 for driving the impeller 12 to rotate. The fan system 1 can be housed within a fan frame 2. In this embodiment, the range hood is a top-mounted type, and also includes a smoke collection hood 3 located below the fan frame 2. Alternatively, it can be a side-mounted, low-mounted, or other existing types of range hoods. The centrifugal fan 1 includes a volute 11, an impeller 12 disposed within the volute 11, and a motor 13 for driving the impeller 12 to rotate.

[0036] After long-term use, oil stains will accumulate on the blades 121 of the impeller 12.

[0037] Therefore, the range hood also includes a detection module 4, which is disposed on the annular wall 112 of the volute 11. This detection module 4 is a terahertz transceiver module. The detection module 4 is disposed on the outer side of the annular wall, and the annular wall of the volute 11 can have openings at the positions corresponding to the detection module 4, so that the detection module 4 can transmit electromagnetic waves to the impeller 12 and receive electromagnetic waves reflected by the impeller 12. See also Figure 9 The detection module 4 includes a transmitting module 41 that can emit electromagnetic waves and a receiving module 42 that can receive reflected electromagnetic waves.

[0038] The volute 11 has a volute tongue 111. On the projection along the axis X of the impeller 12, the projection point of the axis X is O, the projection point of the end of the volute tongue 111 is M1, and the projection point M2 is the center of the contact point between the detection module 4 and the volute 11 (the center along the spiral line of the volute 11). For ease of measurement, all projection points are located on the same plane. The angle formed by the line connecting M1 and O relative to the line connecting M2 and O is α, and the value of α ranges from 20-60°. Since oil easily accumulates at the volute tongue 111, the detection module 4 is offset from the volute tongue 111 by a certain angle. This allows for detection at the smallest possible distance and avoids oil contamination of the detection module 4. A larger angle would increase the distance, hindering detection.

[0039] The range hood also includes a cleaning device for cleaning the centrifugal fan 1, see also Figures 2-6 The cleaning device includes a water tank 51 for storing cleaning media, which can be water or cleaning agent. The water tank 51 can be connected to tap water or other containers. The cleaning device also includes a heating or steam generating module 52, a water pump or water valve 53, a three-way valve 54, a first conduit 551, a second conduit 552, a third conduit 553, a spray arm 56, and a drive mechanism 57.

[0040] The first conduit 551 connects the heating or steam generating module 52 and the spray arm 56 to allow fluid communication between them. The spray arm 56 extends within the volute 11 of the centrifugal fan 1, located between the wall of the volute 11 and the impeller 12, and preferably extends in a direction parallel to the axial direction of the centrifugal fan 1. The spray arm 56 is provided with nozzles 561, which can be used to spray heated or steam-state cleaning media onto the blades 121 of the impeller 12 (or partially onto the volute 11). The spray arm 56 may also be provided with brush heads 562, which can be used to remove oil stains from the blades 121. A drive mechanism 57 is located outside the volute 11 and is used to drive the spray arm 56 to rotate about its own axis (in a direction parallel to the axial direction of the centrifugal fan 1). It can be any existing rotary drive module, such as a motor. This allows the direction of the nozzles 561 and / or brush heads 562 to be changed by driving the spray arm 56 to achieve thorough cleaning, or to rotate the nozzles 561 and / or brush heads 562 toward the wall of the volute 11 when cleaning is not required, reducing the risk of oil clogging and oil accumulation.

[0041] The range hood also includes an electrical box 6, which includes a power board 61 and a radiator 62 for heat dissipation of the power board 61. The radiator 62 can be in the form of heat dissipation fins. The three-way valve 54 is a valve body with one inlet and two outlets. The water tank 51 is connected to one inlet of the three-way valve 54 via a water pump or water valve 53 through a second conduit 552 (the water pump or water valve 53 is located at the connection between the water tank 51 and the second conduit 552 to control whether cleaning medium is supplied). One outlet of the three-way valve 54 is connected to the heating or steam generation module 52, and the other outlet is connected to the water tank 51 via a third conduit 553. The second conduit 552 can bend through the heat dissipation fins of the radiator 62, through which the cleaning medium in the water tank 51 enters the second conduit 552 via a water pump or water valve 53. The cleaning medium in the second conduit 552 exchanges heat with the radiator 62. After being preheated, the cleaning medium enters the three-way valve 54 and then enters the heating or steam generation module 52 to be heated or vaporized, thereby spraying and cleaning through the nozzles 561 on the spray arm 56. Unused cleaning medium can enter the third conduit 553 through the three-way valve 54 and then return to the water tank 51.

[0042] See Figure 9The range hood of this embodiment further includes a processing component 7, which has a processor. The motor 13 (and its drive module) of the centrifugal fan 1, the heating or steam generating module 52 of the cleaning device, the water pump or water valve 53, the drive mechanism 57, and the detection module 4 are all electrically connected to the processing component 7. In addition, the processing component 7 may also be electrically connected to a switch module 71, a storage module 72, and a lamp module 73, which are identical to those in the prior art. The processing component 7 can control the electromagnetic wave emission of the transmitting module 41 of the detection module 4, and determine the thickness and type of oil film accumulated on the blades 121 based on the electromagnetic waves received by the receiving module 42.

[0043] The processing component 7 controls the detection module 4 to emit electromagnetic waves into the volute 11, which are then reflected by the blades 121 of the impeller 12 and received again by the detection module 4. The emission frequency of the detection module 4 is 0.1-1.2 THz, utilizing the specific absorption of terahertz waves by organic matter, such as... Figure 8 As shown, a characteristic absorption peak is observed at 0.53 THz, corresponding to a high oleic acid content (e.g., vegetable oil) at the 121 reflectance of the leaf, while a characteristic absorption peak is observed at 0.68 THz, corresponding to a high cholesterol content (e.g., animal oil) at the 121 reflectance of the leaf. A quantitative relationship between oil film thickness (0–2 mm) and reflectance coefficient was established through combined analysis using time-of-flight (TOF, 1 ps resolution) and frequency domain reflectometer (FDR) measurements (the correlation R was found to be positive in experiments). 2 >0.98). It can not only measure oil film thickness, but also identify oil type through multi-band reflection coefficient fusion analysis, and then make cooking health recommendations and cleaning type recommendations.

[0044] Specifically, the oil film thickness on the blade 121 is achieved using the aforementioned detection module 4. After the detection module 4 sends a signal to the impeller 12, the processing component 7 uses the data received by its receiving module 42 to perform the following calculations:

[0045] I. Calculation of the dielectric constant ε of oil contaminants r :

[0046] The reflection coefficient R is calculated by comparing the frequency domain energy ratio of the signals transmitted and received by detection module 4.

[0047]

[0048] Where E 收 (f) represents the corresponding received signal energy, E 发 (f) represents the energy of the corresponding transmitted signal.

[0049] Thus, the dielectric constant ε of the oil stain is obtained. r :

[0050] II. Calculation of thickness d

[0051] Because terahertz waves penetrate oil fumes without attenuation (THz band characteristic), the thickness can be calculated using the two-way flight time difference of the terahertz wave in the oil layer, and the reference time delay calibrated in the clean state. Where L is the distance from the surface of the blade 121 of the impeller 12 to the receiving module 42 of the detection module 4, and c represents the speed of light. Total delay due to oil contamination. This yields the thickness. Where ε r The dielectric constant is obtained from the above calculations, and Δτ is the time delay difference caused by the oil layer (measured by the time-domain peak deviation and displacement of the transmitted and received signals).

[0052] III. Determining the Type of Oil

[0053] Different oils have characteristic absorption peaks in the terahertz frequency band:

[0054] Oleic acid (vegetable oil) has a characteristic absorption peak at 0.53±0.02 THz, while cholesterol (animal oil) has a characteristic absorption peak at 0.68±0.03 THz. Therefore, comparing the frequency range with the highest absorption can help determine the type of oil used by the user and provide continuous monitoring reference for healthy cooking. Different types of oils have complementary fatty acid compositions, avoiding nutritional imbalance caused by using only one type of oil. If a certain type of oil, such as animal oil, is used for more than a certain number of days, such as 4 days, it is recommended to switch to another type of oil, such as vegetable oil, for 3 days, to achieve a healthy weekly or bi-weekly rotation.

[0055] IV. Prediction of the solidification stage of oil stains using the rate of change of dielectric constant (dε / dt)

[0056] During lipid oxidation, the main components change from triglycerides (>98%) to diglycerides (partially oxidized) + free fatty acids (20-40%). Complete oxidation results in polymers + rancid products (>50%). The overall change in these components during oxidation leads to variations in the dielectric constant ε. r Since the rates of increase are different, the degree of oxidation can be determined by the rate of change of the dielectric constant over time (Δε / Δt). Where Y represents the oxidation index, and ε r (t) represents the dielectric constant currently being detected, ε r (0) represents the dielectric constant recorded when the material has just been cleaned or has not been used.

[0057] The cleaning time can be determined based on the oxidation index Y and the basic cleaning time t. base t clean =t base (1+0.5×Y). Refer to Table 1 for recommended cleaning solutions based on grease type:

[0058]

[0059] Table 1: Oil Types, Oxidation Indexes, and Related Recommended Cleaning Solutions

[0060] By adopting the recommended cleaning schemes described above, as shown in Table 2, it is evident that there has been significant improvement in both cleaning efficiency and energy efficiency.

[0061]

[0062]

[0063] Table 2: Comparison of Cleaning Rate and Energy Consumption Ratio

[0064] The term "fluid connectivity" as used in this utility model refers to the spatial relationship between two components or parts (hereinafter referred to as the first part and the second part, respectively), that is, a fluid (gas, liquid, or a mixture of both) can flow from the first part along a flow path and / or be transported to the second part. This can be a direct connection between the first part and the second part, or an indirect connection between the first part and the second part through at least one third party. The third party can be a fluid channel such as a pipe, channel, conduit, guide, hole, or groove, or a chamber or combination thereof that allows fluid to flow through.

Claims

1. A range hood, comprising a centrifugal fan (1), the centrifugal fan (1) comprising a volute (11) and an impeller (12) disposed within the volute (11), the impeller (12) comprising blades (121); characterized in that: The range hood also includes a detection module (4), which includes a transmitting module (41) capable of transmitting electromagnetic waves with a frequency in the terahertz band to the blade (121) at the corresponding position, and a receiving module (42) capable of receiving the electromagnetic waves reflected by the blade (121). The range hood also includes a processing component (7) that can determine the thickness of the oil film accumulated on the blade (121) based on the electromagnetic wave energy and time delay received by the receiving module (42) and can determine the type of grease accumulated on the blade (121) based on the frequency band with the largest electromagnetic wave absorption received by the receiving module (42). The processing component (7) is electrically connected to the detection module (4).

2. The range hood according to claim 1, characterized in that: The detection module (4) is disposed on the annular wall (112) of the volute (11), and the annular wall (112) has an opening corresponding to the position of the detection module (4).

3. The range hood according to claim 2, characterized in that: The volute (11) has a volute tongue (111). On the projection along the axis (X) of the impeller (12), the projection point of the axis (X) is O, the projection point of the end of the volute tongue (111) is M1, the projection point of the center of the contact between the detection module (4) and the volute (11) is M2, the angle formed between the line connecting M1 and O and the line connecting M2 and O is α, and the value of α is in the range of [20-60°].

4. The range hood according to any one of claims 1 to 3, characterized in that: The range hood also includes a cleaning device, which includes a water tank (51) for storing cleaning medium, a heating or steam generating module (52) for heating or vaporizing the cleaning medium in the water tank (51), and a spray arm (56) for receiving the cleaning medium processed by the heating or steam generating module (52) to clean the centrifugal fan (1).

5. The range hood according to claim 4, characterized in that: The heating or steam generating module (52) and the spray arm (56) are connected in fluid communication through a first conduit (551). The spray arm (56) is located between the wall of the volute (11) and the impeller (12). The spray arm (56) is provided with nozzles (561).

6. The range hood according to claim 5, characterized in that: The spray arm (56) is also equipped with a brush head (562).

7. The range hood according to claim 5, characterized in that: The cleaning device also includes a drive mechanism (57) for driving the spray arm (56) to rotate about a direction parallel to the axis of the centrifugal fan (1).

8. The range hood according to claim 4, characterized in that: The range hood also includes an electrical box (6), which includes a power board (61) and a radiator (62) for heat dissipation of the power board (61); The cleaning device includes a three-way valve (54) with one inlet and two outlets. The water tank (51) is connected to one of the inlets of the three-way valve (54) through a second conduit (552). The heating or steam generating module (52) is connected to one of the outlets of the three-way valve (54). The second conduit (552) passes through the radiator (62).

9. The range hood according to claim 8, characterized in that: The other outlet of the three-way valve (54) is connected to the water tank (51) via a third conduit (553).

10. The range hood according to claim 8, characterized in that: The radiator (62) is finned, and the second conduit (552) bends through each fin of the radiator (62).

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