A range hood

Abstract

The utility model discloses a kind of range hood, including centrifugal fan, the centrifugal fan includes volute and impeller being arranged in volute, the impeller includes blade;The range hood further includes electrostatic discharge device and electrostatic induction module, along the oil fume flow path, the electrostatic discharge device is arranged in the upstream of impeller, and the electrostatic induction module is arranged in the downstream of impeller;The range hood further includes processing assembly that can be judged the oil film thickness accumulated on blade according to the charge amount released by electrostatic discharge device and the charge amount sensed by electrostatic induction module, and the processing assembly is electrically connected with electrostatic discharge device and electrostatic induction module respectively.

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] In addition, some companies use current detection or simple differential pressure detection to determine whether the impeller is contaminated and whether the fan is working properly. However, using current detection alone is easily affected by grid voltage fluctuations, motor efficiency, and motor heating, which can cause attenuation interference. On the other hand, single differential pressure detection cannot distinguish between impeller contamination and front-end filter blockage or rear-end flue blockage. 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 an electrostatic discharge device and an electrostatic induction module. Along the oil fume flow path, the electrostatic discharge device is located upstream of the impeller, while the electrostatic induction module is located downstream of the impeller.

[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 amount of charge released by the electrostatic discharge device and the amount of charge sensed by the electrostatic induction module. The processing component is electrically connected to the electrostatic discharge device and the electrostatic induction module, respectively.

[0012] By utilizing the characteristic that the surface of metal blades has high conductivity, causing the charge to dissipate rapidly, and that the amount of charge increases after the oil film forms, an electrostatic discharge device and an electrostatic induction module are set up to obtain the initial charge and the charge after passing through the impeller. From this, the charge decay time constant that can characterize the oil film thickness is obtained, which can achieve an oil film thickness detection resolution of <0.1mm, which is at least 5 times more accurate than the traditional current detection method.

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

[0014] Furthermore, the volute has a volute tongue. On the projection along the impeller axis, 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 point between the electrostatic induction module and the volute is M2. 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° to 60°. This reduces the impact of oil contamination on the electrostatic induction module.

[0015] To facilitate the installation of the electrostatic discharge device, the range hood also includes a fan frame, and the centrifugal fan and the electrostatic discharge device are installed inside the fan frame.

[0016] 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.

[0017] 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.

[0018] Furthermore, the spray arm is also equipped with a brush head, which can brush away the softened oil stains on the blades.

[0019] 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.

[0020] Furthermore, the range hood also includes an electrical box, which includes a power board and a radiator for heat dissipation of the power board;

[0021] 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.

[0022] 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.

[0023] Compared with the prior art, the advantages of this utility model are as follows: by utilizing the characteristic that the surface of metal blades has strong conductivity, which causes the charge to dissipate rapidly, and that the amount of charge increases after the oil film is formed, an electrostatic discharge device and an electrostatic induction module are set up to obtain the initial charge and the charge after passing through the impeller. From this, the charge decay time constant that can characterize the oil film thickness is obtained, which can achieve an oil film thickness detection resolution of <0.1mm, which is at least 5 times more accurate than the traditional current detection method. 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 the degree of impeller contamination and the charge dissipation time 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 prolonged use, grease accumulates on the blades 121 of the impeller 12. The blades 121 are typically metal, and the accumulation of grease increases their dielectric constant (e.g., to 3, while air is 1). Therefore, an electrostatic discharge device 41 can be installed upstream of the impeller 12 along the fume flow path. This charges the fume particles moving with the airflow, and the resulting static electricity helps the grease accumulate and improves grease separation. It can also serve as a medium for detecting the degree of dirt on the blades 121. In this embodiment, it is installed inside the fan frame 2, opposite the air inlet of the centrifugal fan 1 (located on the volute 11). An electrostatic induction module 42 is installed downstream of the impeller 12 along the fume flow path to measure the residual charge after charged particles collide with the impeller. In this embodiment, the electrostatic induction module 42 is installed on the volute 11 (where the airflow flows into the volute after exiting the impeller 12), particularly on the annular wall 112 of the volute 11. Because the surface of a clean metal blade has high conductivity, the charge dissipates quickly. However, once an oily film forms, the residual charge increases, and due to the increased dielectric constant, the charge does not dissipate easily. A filter (such as a Kalman filter) can be used to estimate the charge decay time constant τ in real time. When the value of τ increases from <5ms to >20ms, a dirt alarm is triggered. Because the measurement is non-contact, it avoids the various drawbacks of mechanical or other contact measurements.

[0037] 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 electrostatic induction module 42 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 electrostatic induction module 42 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 electrostatic induction module 42. A larger angle would increase the distance, hindering detection.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] See Figure 9 The 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, the electrostatic discharge device 41, and the electrostatic induction module 42 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 the same as in the prior art. The processing component 7 can control the discharge of the electrostatic discharge module 41 and determine the thickness (degree of contamination) of the oil film accumulated on the blades 121 based on the charge signal received by the electrostatic induction module 42.

[0042] The specific algorithm is as follows: charge decay model Q(t) = Q0e -t / τ Where Q(t) represents the amount of induced charge monitored at time t, in nC, and Q0 is the initial charge amount released by the electrostatic discharge device 41. τ is the time constant, a key parameter characterizing oil film thickness. The larger τ is, the higher the degree of contamination (oil film thickness). The relationship between the two can be obtained experimentally; see [reference needed]. Figure 8 The critical value of τ requiring cleaning can be set as needed. Since the rotation of impeller 12 may affect the detected value, a certain correction can be made based on the impeller 12's rotational speed. At this time, the charge decay model Q(t) = Q0e -t / τ +kωt, where ω is the real-time rotational speed of impeller 12 in rad / s, and k is a constant (which can be determined as an empirical value or obtained through experiments). The rotational speed of impeller 12 can be obtained from the rotational speed of motor 13, or the rotational speed can be detected separately.

[0043] In the above model, the electrostatic induction module 42 senses Q(t) at time t, and kωt is the dynamic compensation based on the real-time speed data of the impeller (compensation is not required when the speed fluctuation of the impeller 12 is small). The real-time measurement time constant τ can then be obtained directly, or the compensated data can be filtered (such as a Kalman filter) to eliminate random errors such as noise and electromagnetic interference, resulting in the real-time measurement time constant τ. The cleaning device can be controlled based on this measured time constant τ, or it can be corrected based on τ and its rate of change (dτ / dt) at the previous moment.

[0044] Preferably, the processing component 7 can control the cleaning device by referring to the charge decay time constant alone, or it can control the cleaning device by combining the charge decay time constant and the rate of change, as shown in Table 1, which is one control method of this utility model.

[0045]

[0046]

[0047] Table 1: Control methods based on time constant and rate of change

[0048] The self-cleaning degree in the table above refers to the use of the cleaning device described above for cleaning with water. The water pressure requirement is ≥0.2MPa (micro water pump flow rate ≥200ml / min).

[0049] The oil-throwing mode described in the table above can be specifically described as follows: First, the speed of motor 13 can be increased to, for example, 3000 rpm and then stopped abruptly. Then, the power is reversed to cause the impeller to rotate at 500 rpm for 30 seconds. This mainly utilizes centrifugal force F=mω 2 r implementation.

[0050] 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 an electrostatic discharge device (41) and an electrostatic induction module (42). Along the oil fume flow path, the electrostatic discharge device (41) is located upstream of the impeller (12), while the electrostatic induction module (42) is located downstream of the impeller (12). The range hood also includes a processing component (7) that can determine the thickness of the oil film accumulated on the blades (121) based on the amount of charge released by the electrostatic discharge device (41) and the amount of charge sensed by the electrostatic induction module (42). The processing component (7) is electrically connected to the electrostatic discharge device (41) and the electrostatic induction module (42) respectively.

2. The range hood according to claim 1, characterized in that: The electrostatic induction module (42) 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 electrostatic induction module (42).

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 electrostatic induction module (42) 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 claim 1, characterized in that: The range hood also includes a fan frame (2), and the centrifugal fan (1) and electrostatic discharge device (41) are installed inside the fan frame (2).

5. The range hood according to any one of claims 1 to 4, 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).

6. The range hood according to claim 5, 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).

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

8. The range hood according to claim 6, 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).

9. The range hood according to claim 5, 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).

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

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