An anti-backflow oil fume control system and an intelligent control method thereof

Abstract

The application discloses a kind of anti-backflow cooking fume control systems and its intelligent control method, the anti-backflow cooking fume control system, including range hood and cooking utensil, the range hood has fan, the range hood is discharged by flue gas duct, and electric valve is arranged at the flue gas duct outlet;The range hood further includes: networking module, can be connected to obtain the real-time wind and rain state of the range hood location;And main controller, for controlling fan and electric valve according to the information obtained by networking module and the cooking state of cooking utensil.Compared with prior art, the advantages of the present application are: by obtaining the real-time weather wind speed condition of user local, the cooking utensil fire state can be obtained by combining the linkage of range hood and cooking utensil, the working state of outlet electric valve and range hood fan is adjusted using the information of the two, solve the wind and rain backflow problem of different use scenarios.

Description

Technical Field

[0001] This invention relates to oil fume purification technology, and in particular to an anti-backflow oil fume control system and an intelligent control method for the system. Background Technology

[0002] Range hoods are essential kitchen appliances for people to remove cooking fumes. As users pay more and more attention to the user experience, range hoods and cooktops are now focusing more on the intelligence and automation of the cooking process.

[0003] Modern residential designs predominate in high-rise buildings, and some range hoods require connection to a shared flue for centralized exhaust at the rooftop to enhance the aesthetics of the building's facade. However, lower-rise buildings, villas, and certain areas like Wuhan still rely on direct exhaust. During windy weather, backflow due to pressure differentials can cause airflow to enter branch pipes through the flue outlet, especially when neighbors are cooking and the user's home is not, easily leading to odors entering the user's room. While some users have installed fire-resistant backflow preventers, the technology disclosed in Chinese patents such as applications 201911390837.0 and 202320198701.5 can reduce backflow to some extent. However, due to pressure fluctuations within the flue, these preventers can still open and close passively, causing some odors to flow back. This can pollute the air in the user's kitchen and even living room when the range hood is not in use, leading to complaints about backflow and odor transfer (backflow and odor transfer from the flue account for the highest percentage of complaints against range hood manufacturers).

[0004] Therefore, further improvements are needed. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide an anti-backflow oil fume control system that addresses the shortcomings of the prior art and can solve the problem of wind and rain backflow in different usage scenarios.

[0006] The second technical problem to be solved by the present invention is to provide an intelligent control method for the above-mentioned anti-backflow oil fume control system.

[0007] The technical solution adopted by this invention to solve the first technical problem mentioned above is as follows: an anti-backflow oil fume control system, comprising a range hood and a stove, wherein the range hood has a fan, the range hood exhausts oil fume through an exhaust pipe, and an electric valve is provided at the exhaust port of the exhaust pipe; characterized in that:

[0008] The range hood also includes:

[0009] The network module can connect to the internet to obtain real-time weather conditions at the location of the range hood; and

[0010] The main controller is used to control the fan and electric valve based on information obtained from the network module and the cooking status of the stove.

[0011] By obtaining real-time local weather and wind speed information, and combining this with the linkage between the range hood and the cooktop, the cooktop's ignition status can be obtained. By combining this information, the operating status of the outlet electric valve and the range hood fan can be adjusted to solve the problem of wind and rain backflow in different usage scenarios.

[0012] Furthermore, to facilitate the main controller's control of the fan, the range hood also includes a fan drive module for driving the fan, and the main controller and the fan drive module are electrically connected.

[0013] Furthermore, to facilitate the storage and retrieval of detected values ​​and preset values, the range hood also includes a memory electrically connected to the main controller.

[0014] The technical solution adopted by the present invention to solve the second technical problem mentioned above is: an intelligent control method for the anti-backflow oil fume control system as described above, characterized in that: the intelligent control method includes the following steps:

[0015] Step 1: System startup;

[0016] Step 2: Acquire user status and weather data in real time;

[0017] Step 3: Determine whether the user is cooking based on the user status in Step 2. If yes, proceed to Step 4; otherwise, proceed to Step 6.

[0018] Step 4: Determine whether the wind and rain exceed the limits based on the meteorological data from Step 2. If yes, proceed to Step 5; otherwise, conduct routine smoke extraction.

[0019] Step 5: The system runs in BOOST mode, controlling the fan speed to increase pressure. Then, when cooking is finished, it enters DELAY mode, controlling the fan speed to increase pressure. After a period of time, the electric valve is closed, controlling the range hood to stop.

[0020] Step 6: The system is running in SEAL mode, the electric valve is closed, and the range hood fan remains off.

[0021] By obtaining real-time local weather and wind speed information, and combining the linkage between the range hood and the cooktop, the cooking status of the cooktop can be obtained. By combining the information from both, the working status of the outlet electric valve and the range hood fan can be adjusted in two modes: "sealed isolation" and "dynamic pressurization". This solves the problem of wind and rain backflow in different usage scenarios. When not cooking, it achieves zero-energy sealing to prevent wind, rain and biological intrusion. When cooking, it uses Bernoulli's equation to dynamically stabilize the pressure, preventing backflow while ensuring smoke exhaust. After shutdown, it provides delayed positive pressure protection to block water backflow.

[0022] Furthermore, the pressurization method in BOOST mode is as follows: In step 5, in BOOST mode, the target pressure... for:

[0023] +

[0024] in, The comprehensive wind pressure conversion coefficient, The value range is 0.5 to 0.8. For the pre-calibrated building drag coefficient, air density, The real-time wind speed is obtained by the network module through the meteorological API; , The length of the exhaust duct, Let be the friction coefficient of the exhaust duct, and Q be the known real-time airflow of the range hood; For safety margin;

[0025] Target speed of the wind turbine Reference speed relative to the current gear The percentage that needs to be increased is:

[0026]

[0027] in, .

[0028] Furthermore, the pressurization method in DELAY mode is as follows: In step 5, in DELAY mode, the pressurization is performed according to the following formula:

[0029]

[0030] Thus, the fan speed in DELAY mode is obtained. This refers to the time for delayed pressurization.

[0031] Furthermore, in step 4, exceeding the wind and rain limit refers to... ,in This refers to the rainfall intensity obtained by the network module; It is the real-time wind speed obtained by the network module.

[0032] Compared with the prior art, the advantages of the present invention are: by obtaining the user's local real-time weather and wind speed, and by combining the linkage between the range hood and the stove, the stove's ignition status can be obtained. By combining the information from both, the working status of the outlet electric valve and the range hood fan can be adjusted, thus solving the problem of wind and rain backflow in different usage scenarios.

[0033] By obtaining real-time local weather and wind speed information, and combining the linkage between the range hood and the cooktop, the cooking status of the cooktop can be obtained. By combining the information from both, the working status of the outlet electric valve and the range hood fan can be adjusted in two modes: "sealed isolation" and "dynamic pressurization". This solves the problem of wind and rain backflow in different usage scenarios. When not cooking, it achieves zero-energy sealing to prevent wind, rain and biological intrusion. When cooking, it uses Bernoulli's equation to dynamically stabilize the pressure, preventing backflow while ensuring smoke exhaust. After shutdown, it provides delayed positive pressure protection to block water backflow. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the installation of the range hood in the fume control system of this invention.

[0035] Figure 2 This is a block diagram illustrating the control principle of the range hood in the fume control system of this invention.

[0036] Figure 3 This is a flowchart illustrating the intelligent control process of the fume control system according to an embodiment of the present invention.

[0037] Figure 4 This is a flowchart of the working mode one of the oil fume control system according to an embodiment of the present invention;

[0038] Figure 5 This is a flowchart of the second working mode of the oil fume control system according to an embodiment of the present invention;

[0039] Figure 6 This is a flowchart of the third working mode of the oil fume control system according to an embodiment of the present invention. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0041] 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.

[0042] See Figure 1 and Figure 2 A backflow prevention oil fume control system includes a range hood 1, an exhaust pipe 2, and an electric valve 3. The range hood 1 discharges oil fumes through the exhaust pipe 2 (to a public flue or outdoors). An electric valve 3 is installed at the exhaust port 21 of the exhaust pipe 2 to prevent oil fume backflow.

[0043] The range hood 1 includes a fan frame 12 and a fan (not shown in the figure, representing prior art) disposed within the fan frame 12. The fan is typically a centrifugal fan. The form of the range hood is not limited; this embodiment shows a top-mounted type, but it can also be any form such as a side-mounted, ceiling-mounted, or low-mounted type.

[0044] The range hood 1 also includes a control module (all existing range hoods have a control module), which includes a main controller 11. The main controller 11 is electrically connected to the electric valve 3 and can receive information from the electric valve 3. The control module also includes a fan drive module 13 and a network module 14. The main controller 11 is electrically connected to both the fan drive module 13 and the network module 14, thereby controlling the fan through the fan drive module 13 and accessing the Internet through the network module 14. The main controller 11 drives the fan through the fan drive module 13 using existing technology, and the network module 14 also uses existing technology, such as a WIFI module. The control module may also include a memory 15, a switch module 16, etc., which are electrically connected to the main controller 11 for data storage and retrieval, and for controlling the start and stop of the range hood 1.

[0045] The main controller 11 can be connected to the meteorological API (Application Programming Interface) via the networking module 14. The meteorological API is a set of rules and tools that meteorological service providers (such as meteorological bureaus and weather data companies) open to developers, thereby obtaining the local real-time wind and rain conditions, including real-time wind speed, real-time rainfall intensity, and typhoon warning level.

[0046] Furthermore, the system of this invention also includes a commonly used cooktop (not shown), which is installed in the prior art, i.e., below the range hood 1, enabling linkage detection of the cooktop's status. This is prior art, as disclosed in Chinese patent applications 202410491783.1 and 202511829520.8. Alternatively, the system of this invention can also achieve human body sensing, such as by incorporating an infrared sensor.

[0047] The intelligent control method for preventing backflow in the system of this invention is described in [reference needed]. Figure 3 It includes the following steps:

[0048] Step 1: System startup;

[0049] Step 2: Acquire user status and meteorological data in real time. The real-time acquired "user status" is a comprehensive judgment signal, mainly obtained through one or more of the following methods:

[0050] Cooktop and range hood linkage signal: The on / off status of the smart cooktop is directly obtained through communication protocols (such as Wi-Fi, Bluetooth, infrared). When the cooktop is turned on, it is determined to be "cooking". This method is preferred for judgment.

[0051] Human body sensing signal: Detects whether there is human activity in front of the stove by using microwave or infrared sensors installed in the range hood, stove or kitchen.

[0052] Range hood status: When the user manually turns on the range hood to any setting, it is automatically determined to be in a cooking-related state.

[0053] Step 3: Determine whether the user is cooking based on the user status in Step 2. If yes, proceed to Step 4; otherwise, proceed to Step 6.

[0054] Step 4: Determine whether the wind and rain exceed the limits based on the meteorological data from Step 2. If yes, proceed to Step 5; otherwise, conduct routine smoke extraction.

[0055] Step 5: The system runs in BOOST mode (working mode two), and then when cooking is finished (judgment method is the same as step 3), it enters DELAY mode (working mode three), closes electric valve 3, and the range hood 1 stops.

[0056] Step 6: The system is running in SEAL mode (working mode one), and the electric valve is closed.

[0057] In the above steps, SEAL mode refers to the non-cooking state. When a typhoon and / or heavy rain is detected, and the user's status is "not cooking," the electric valve 3 is immediately closed, and the fan of the range hood 1 remains off, blocking the backflow of wind and rain. Energy consumption is 0 (the operation of electric valve 3 alone consumes approximately 0.1Wh). Its operating logic can be found in [link to relevant documentation]. Figure 4 .

[0058] BOOST mode refers to the operating mode during cooking. When a typhoon and / or heavy rain is detected, the fan dynamically increases pressure using the following formula. :

[0059] The calculated target total wind pressure needs to overcome environmental wind and rain backflow pressure, pipeline losses, and maintain a safety margin; among which, This indicates wind pressure compensation. The physical essence of the comprehensive wind pressure conversion coefficient is 0.5 comes from the dynamic pressure term of Bernoulli's equation. 1 / 2 of the, and (Approximately 1.2) is an empirical correction factor. It takes into account: a) the wind does not directly impact the flue outlet perpendicularly, resulting in angular reduction; b) the interference of building edges, rain shelters, and other structures on the wind field; and c) the wind speed obtained from the meteorological API is an open environment value, not the actual wind speed at the building surface. The determination method is as follows: by comparing the measured critical backflow wind pressure and API wind speed in a wind tunnel laboratory or in the field (different floors and different apartment types), statistical regression is performed to obtain the value, which is usually between 0.5 and 0.8, with 0.6 being a typical median value; This is the building drag coefficient, reflecting the amplification effect of floor height and building density on wind pressure. The higher the floor, the less obstruction there is, and the greater the wind pressure. This is a pre-calibrated value from the laboratory. During calibration, a 3D model of a standard residential building was created using computational fluid dynamics (CFD) software to simulate the wall wind pressure distribution on different floors (e.g., floors 1-30) under the average wind field. The pressure coefficient at the outlet of exhaust duct 2 was extracted and normalized. Table 1 below gives some typical values:

[0060]

[0061] Table 1: Relationship between Building Drag Coefficient and Floor Level

[0062] After the range hood is installed, you can connect to it via your mobile phone and then determine the appropriate settings based on the floor level. ; For air density, a constant value can be used, such as 1.29 kg / m³. The real-time wind speed is obtained by the network module 14 through the meteorological API;

[0063] , The length of the exhaust duct 2 is known at the time of installation. Let be the coefficient of friction of exhaust duct 2 (once exhaust duct 2 is selected, the coefficient of friction is determined), and Q be the known real-time air volume of the range hood; For safety margin, a value of 15 Pa can be selected to cover turbulent fluctuations (wind tunnel measured data). Furthermore, the fan output pressure P (target control variable) and speed N follow the fan similarity law:

[0064] in, The characteristic coefficient of a fan is an inherent constant that relates fan speed, size, and output air pressure. It is uniquely determined by the geometric characteristics of the fan impeller, such as its profile, number of blades, and installation angle. It can be calibrated in advance. The calibration process is as follows: a) Install the fan (excluding ductwork) on a wind tunnel test bench or airflow testing device that conforms to national standards; b) Adjust the fan speed to multiple stable points (e.g., 800, 1200, 1600, 2000 rpm) under rated voltage; c) At each speed point, measure the static pressure (Pa) at the fan outlet using a differential pressure gauge and measure the airflow (m³ / h) using an airflow hood; d) With the fan in a completely closed state (airflow zero), measure the maximum static pressure at different speeds. The formula is then used. Most accurate (because there is no flow loss); e) Perform quadratic curve fitting on multiple sets of data (speed N, static pressure P), fitting formula The coefficient 'a' of the quadratic term in the equation contains... Information, due to Given that, it can be deduced that... ; Typical options include multi-blade centrifugal fans or turbine fans commonly used in household range hoods. The value range is usually in ~ D is the impeller diameter of the fan.

[0065] Therefore, for the same wind turbine The target wind pressure that the wind turbine needs to provide when there is no wind or rain. Low-noise smoke extraction can be achieved simply by overcoming pipeline losses and ensuring a safety margin. At this point, the environmental backflow pressure is 0, therefore:

[0066]

[0067] When there is no wind or rain, If the term is 0, then ;

[0068] Therefore, the fan speed at this time ( Relative to The percentage that needs to be increased is:

[0069]

[0070] This yields the target speed for boost regulation. Its operating logic can be found in [reference]. Figure 5 . The reference speed is the default operating speed of the system when there is no wind pressure compensation requirement (α=0). This value is not a fixed constant, but is adjusted according to the machine type or user operation mode: User manual mode: The corresponding nominal speed for the selected gear (e.g., low gear 600rpm, medium gear 900rpm, high gear 1200rpm); Pre-ventilation mode: Set to the lowest sustainable operating speed (typically 300 rpm, to maintain positive pressure in the flue). In calm weather, follow the normal exhaust procedure described in step 4. .

[0071] DELAY mode refers to the operating mode during cooking. Upon detecting a typhoon and / or heavy rain, a delay increase is implemented, with pressurization calculated according to the following formula:

[0072]

[0073] Thus, the rotational speed in the delay mode is obtained. This gradually reduces the pressure to prevent steam condensation in the flue, and the pressurization time... The system adapts to the length of the exhaust duct 2 and the real-time wind speed (to prevent instantaneous pressure drop). Its operating logic can be found in [reference needed]. Figure 5 .

[0074] In summary, the state transition formula is:

[0075]

[0076] in, : The cooking status is obtained through the linkage between the range hood and the cooktop (0 = cooktop off, 1 = cooking). The network module obtains the typhoon warning level (e.g., 0-17) through the weather forecast API; The network module obtains rainfall intensity (mm / h) through the weather forecast API; The network module obtains real-time wind speed (m / s) through the weather forecast API.

Claims

1. A backflow prevention oil fume control system, comprising a range hood (1) and a stove, wherein the range hood (1) has a fan, the range hood (1) exhausts oil fume through an exhaust pipe (2), and an electric valve (3) is provided at the exhaust port (21) of the exhaust pipe (2); characterized in that: The range hood (1) also includes: The networking module (14) is capable of connecting to the network to obtain real-time weather conditions at the location of the range hood (1); and The main controller (11) is used to control the fan and electric valve (3) based on the information obtained from the networking module (14) and the cooking status of the stove.

2. The anti-backflow fume control system according to claim 1, characterized in that: The range hood (1) also includes a fan drive module (13) for driving the fan, and the main controller (11) and the fan drive module (13) are electrically connected.

3. The anti-backflow fume control system according to claim 1, characterized in that: The range hood (1) also includes a memory (15) electrically connected to the main controller (11).

4. An intelligent control method for an anti-backflow oil fume control system as described in any one of claims 1 to 3, characterized in that: The intelligent control method includes the following steps: Step 1: System startup; Step 2: Acquire user status and weather data in real time; Step 3: Determine whether the user is cooking based on the user status in Step 2. If yes, proceed to Step 4; otherwise, proceed to Step 6. Step 4: Determine whether the wind and rain exceed the limits based on the meteorological data from Step 2. If yes, proceed to Step 5; otherwise, conduct routine smoke extraction. Step 5: The system runs in BOOST mode, controls the fan speed to increase pressure, and then enters DELAY mode when cooking is finished, controls the fan speed to increase pressure, and closes the electric valve (3) after a period of time to stop the range hood (1). Step 6: The system is running in SEAL mode, the electric valve (3) is closed, and the fan of the range hood (1) remains off.

5. The intelligent control method for the anti-backflow oil fume control system according to claim 4, characterized in that: In step 5, in BOOST mode, the target pressure for: + in, The comprehensive wind pressure conversion coefficient, The value range is 0.5 to 0.

8. For the pre-calibrated building drag coefficient, air density, The real-time wind speed is obtained by the networking module (14) through the meteorological API; , The length of the exhaust pipe (2) is... Let Q be the friction coefficient of the exhaust duct (2), and let Q be the known real-time airflow of the range hood (1). For safety margin; Target speed of the wind turbine Reference speed relative to the current gear The percentage that needs to be increased is: in, .

6. The intelligent control method for the anti-backflow oil fume control system according to claim 4, characterized in that: In step 5, in DELAY mode, the boost is performed according to the following formula: Thus, the fan speed in DELAY mode is obtained. This refers to the time for delayed pressurization.

7. The intelligent control method for the anti-backflow oil fume control system according to claim 4, characterized in that: In step 4, exceeding the wind and rain limit refers to... ,in This refers to the rainfall intensity obtained by the network module (14); It is the real-time wind speed obtained by the network module (14).

Images