Anti-backflow control method, control device, control system and storage medium

Abstract

The invention discloses an anti-backflow control method, an anti-backflow control device, an anti-backflow control system and a computer readable storage medium. The anti-backflow control method provided by the embodiment of the invention is applied to the range hood. The range hood comprises a pressure sensor and a fan. The pressure sensor is used for sampling and detecting the current pressure value in the range hood. The anti-backflow control method comprises the following steps: acquiring n current pressure values detected by a pressure sensor in n sampling periods; acquiring (n + theta) current pressure values detected by the pressure sensor in (n + theta) sampling periods; according to the n current pressure values of the n sampling periods and the (n + theta) current pressure values of the (n + theta) sampling periods, the working state of the draught fan is controlled; wherein n > = 1, and theta > = 1. Therefore, the working state of the fan can be accurately controlled, so that the effect of discharging the backward flowing oil smoke is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of kitchen appliances, in particular to a backflow prevention control method, a backflow prevention control device, a backflow prevention control system and a computer readable storage medium. BACKGROUND

[0002] With the widespread use of public flues for centralized smoke exhaust in high-rise buildings, the problem of oil fume backflow has become increasingly prominent and has become a difficult problem for residents. Although the current air exhaust hood is equipped with mechanical devices such as check valves at the air outlet, due to the existence of gas molecule diffusion effect and the difficulty in achieving complete gap-free sealing performance at the air outlet, such devices still have certain limitations in preventing oil fume backflow. In addition, such devices will inevitably be contaminated by oil fumes during long-term use, resulting in uncertainty in their opening and closing functions, which in turn affects the backflow prevention effect. SUMMARY

[0003] The embodiments of the present application provide a backflow prevention control method, a backflow prevention control device, a backflow prevention control system and a computer readable storage medium to solve at least one of the above technical problems.

[0004] The backflow prevention control method of the embodiments of the present application is applied to a hood, and the hood includes a pressure sensor and a fan. The pressure sensor is used to sample and detect the current pressure value inside the hood. The backflow prevention control method includes:

[0005] Obtaining n current pressure values detected by the pressure sensor in n sampling periods;

[0006] Obtaining (n+θ) current pressure values detected by the pressure sensor in (n+θ) sampling periods;

[0007] Controlling the working state of the fan according to the n current pressure values in the n sampling periods and the (n+θ) current pressure values in the (n+θ) sampling periods; wherein n≥1, θ≥1.

[0008] In some embodiments, controlling the working state of the fan according to the n current pressure values in the n sampling periods and the (n+θ) current pressure values in the (n+θ) sampling periods includes:

[0009] Calculating the pressure average value of the n sampling periods according to the n current pressure values in the n sampling periods;

[0010] Calculating the pressure average value of the (n+θ) sampling periods according to the (n+θ) current pressure values in the (n+θ) sampling periods;

[0011] Controlling the working state of the fan according to the pressure average value of the n sampling periods and the pressure average value of the (n+θ) sampling periods.

[0012] In some embodiments, the working state of the fan is controlled according to the pressure average value of n sampling periods and the pressure average value of (n+θ) sampling periods, including:

[0013] determining whether a first pressure difference between the pressure average value of (n+θ) sampling periods and the pressure average value of n sampling periods is greater than a first predetermined threshold value;

[0014] when the first pressure difference is greater than the first predetermined threshold value, controlling the fan to be turned on.

[0015] In some embodiments, in the process of controlling the working state of the fan according to n current pressure values of n sampling periods and (n+θ) current pressure values of (n+θ) sampling periods, the anti-inversion control method further includes:

[0016] obtaining an (n-1)th current pressure value detected by the pressure sensor in the (n-1)th sampling period;

[0017] obtaining an nth current pressure value detected by the pressure sensor in the nth sampling period;

[0018] determining whether a second pressure difference between the nth current pressure value of the nth sampling period and the (n-1)th current pressure value of the (n-1)th sampling period is greater than a second predetermined threshold value;

[0019] when the second pressure difference is greater than the second predetermined threshold value, taking the (n-1)th current pressure value of the (n-1)th sampling period as the nth current pressure value of the nth sampling period.

[0020] In some embodiments, the anti-inversion control method further includes:

[0021] obtaining (n-1) current pressure values detected by the pressure sensor in (n-1) sampling periods;

[0022] obtaining an nth current pressure value detected by the pressure sensor in the nth sampling period;

[0023] controlling the working state of the fan according to the (n-1) current pressure values of (n-1) sampling periods and the nth current pressure value of the nth sampling period.

[0024] In some embodiments, the working state of the fan is controlled according to the (n-1) current pressure values of (n-1) sampling periods and the nth current pressure value of the nth sampling period, including:

[0025] calculating a pressure average value of (n-1) sampling periods according to the (n-1) current pressure values of (n-1) sampling periods;

[0026]

[0026] determining whether a third pressure difference between the n th current pressure value of the n th sampling period and the pressure average of the (n-1) th sampling period is less than a third predetermined threshold value;

[0027] controlling the fan to be turned off when the third pressure difference is less than the third predetermined threshold value.

[0028] In some embodiments, before obtaining the n current pressure values detected by the pressure sensor in the n sampling periods, the anti-backflow control method further comprises:

[0029] determining whether the pressure sensor is faulty;

[0030] displaying a fault code to remind the user when the pressure sensor is faulty;

[0031] when the pressure sensor is not faulty, entering the step of obtaining the n current pressure values detected by the pressure sensor in the n sampling periods.

[0032] The anti-backflow control device of the embodiments of the present application is applied to a range hood, the range hood comprising a pressure sensor and a fan, the pressure sensor being configured to sample and detect a current pressure value inside the range hood, and the anti-backflow control device comprising:

[0033] a first obtaining module configured to obtain n current pressure values detected by the pressure sensor in n sampling periods;

[0034] a second obtaining module configured to obtain (n+θ) current pressure values detected by the pressure sensor in (n+θ) sampling periods;

[0035] a control module configured to control a working state of the fan according to the n current pressure values of the n sampling periods and the (n+θ) current pressure values of the (n+θ) sampling periods; wherein n≥1 and θ≥1.

[0036] The anti-backflow control system of the embodiments of the present application comprises one or more processors and a memory, the memory storing a computer program, and the computer program being executed by the processor to implement the anti-backflow control method of any of the above embodiments.

[0037] The computer readable storage medium of the embodiments of the present application stores a computer program, and the program being executed by the processor to implement the anti-backflow control method of any of the above embodiments.

[0038] The anti-backflow control method, the anti-backflow control device, the anti-backflow control system and the computer readable storage medium of the embodiments of the present application can accurately control the working state of the fan according to the n current pressure values of n sampling periods and the (n+θ) current pressure values of (n+θ) sampling periods, so as to achieve the effect of discharging backflow oil fume.

[0039] Additional aspects and advantages of the embodiments of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0040] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the appended drawings.

[0041] Figure 1 is a flowchart of the anti-backflow control method of some embodiments of the present application;

[0042] Figure 2 is a module diagram of the range hood of some embodiments of the present application;

[0043] Figure 3 is a flowchart of the anti-backflow control method of some embodiments of the present application;

[0044] Figure 4 is a flowchart of the anti-backflow control method of some embodiments of the present application;

[0045] Figure 5 is a flowchart of the anti-backflow control method of some embodiments of the present application;

[0046] Figure 6 is a module diagram of the anti-backflow control device of some embodiments of the present application;

[0047] Figure 7 is a module diagram of the anti-backflow control system of some embodiments of the present application;

[0048] Figure 8 is a connection state diagram of the computer readable storage medium and the processor of some embodiments of the present application.

[0049] REFERENCE SIGNS:

[0050] Anti-backflow control device 100, first acquisition module 10, second acquisition module 20, control module 30, anti-backflow control system 200, processor 210, memory 220, computer readable storage medium 300, computer program 310, processor 320, range hood 1000, pressure sensor 1001, controller 1002, fan 1003. DETAILED DESCRIPTION

[0051] The embodiments of the present application will be further described with reference to the drawings. Like or similar components in the drawings are designated by like reference numerals, and the description thereof will not be repeated. In addition, the embodiments of the present application described below with reference to the drawings are merely exemplary and are used to explain the embodiments of the present application, and should not be understood as limiting the present application.

[0052] Referring to Figures 1 to 3 The anti-backflow control method of the embodiments of the present application is applied to a range hood 1000. The range hood 1000 includes a pressure sensor 1001 and a fan 1003. The pressure sensor 1001 is configured to sample and detect a current pressure value inside the range hood 1000. The anti-backflow control method includes the following steps.

[0053] S10: obtaining n current pressure values detected by the pressure sensor 1001 in n sampling periods;

[0054] S20: obtaining (n+θ) current pressure values detected by the pressure sensor 1001 in (n+θ) sampling periods;

[0055] S30: controlling a working state of the fan 1003 according to the n current pressure values in the n sampling periods and the (n+θ) current pressure values in the (n+θ) sampling periods; wherein n≥1, θ≥1.

[0056] The anti-backflow control method of the embodiments of the present application can accurately control the working state of the fan 1003 according to the n current pressure values in the n sampling periods and the (n+θ) current pressure values in the (n+θ) sampling periods, so as to achieve the effect of discharging backflowing oil fume.

[0057] Specifically, referring to Figure 2 The range hood 1000 can include the pressure sensor 1001, a controller 1002 and the fan 1003.

[0058] The pressure sensor 1001 is configured as a detection device, and is configured to detect a pressure value inside the range hood 1000. The pressure sensor 1001 is arranged inside the range hood 1000, for example, between an air outlet of the range hood 1000 and a check valve, so as to accurately perceive a pressure change inside the range hood 1000 in real time.

[0059] The controller 1002 can be a microcontroller unit (MCU). The controller 1002 serves as a control system for obtaining the pressure value detected by the pressure sensor 1001, and uses the pressure value detected by the pressure sensor 1001 in combination with a relevant algorithm to determine whether the extractor hood 1000 has oil fume backflow, and sends a control instruction to the fan 1003 to control the working state of the fan 1003, for example, to turn on or turn off the fan 1003.

[0060] The fan 1003 serves as an actuator, and when receiving the control instruction sent by the controller 1002, the fan 1003 responds quickly and performs corresponding actions. For example, when the extractor hood 1000 has oil fume backflow, the controller 1002 sends an on instruction to the fan 1003 to control the fan 1003 to turn on. The fan 1003 is then started to change the pressure condition inside the extractor hood 1000 by generating a strong airflow to form a reverse airflow barrier to prevent further backflow of external oil fume and to discharge the backflow oil fume.

[0061] The working process of the backflow prevention control method of the embodiment of the application will be introduced below in combination with specific examples:

[0062] First, the chip of the controller 1002 is initialized. Through the initialization operation, a stable and known working environment can be created for the chip, and it is ensured that the registers, clock, interrupt system and other functional modules inside the chip are in a default and predictable state, so as to lay a foundation for the normal operation of the subsequent program.

[0063] Then, the pressure sensor 1001 continuously monitors the pressure inside the extractor hood 1000 to sample the current pressure value inside the extractor hood 1000. In an example, the sampling period can be 0.5 seconds.

[0064] During the sampling of the current pressure value by the pressure sensor 1001, the controller 1002 obtains n current pressure values detected by the pressure sensor 1001 in n sampling periods. Taking n = 10 as an example, the controller 1002 obtains 10 current pressure values detected by the pressure sensor 1001 in 10 sampling periods, which can be represented as P1, P2, P3, …, P9, P10 respectively. 10 .

[0065] The controller 1002 obtains (n + θ) current pressure values detected by the pressure sensor 1001 in (n + θ) sampling periods. Taking θ = 5 as an example, n + θ = 15. The controller 1002 obtains 15 current pressure values detected by the pressure sensor 1001 in 15 sampling periods, which can be represented as P1, P2, P3, …, P14, P15 respectively. 14 , P 15. Among the 15 current pressure values detected in the 15 sampling periods, the 10 current pressure values detected in the first 10 sampling periods are the same as the 10 current pressure values detected by the pressure sensor 1001 in the 10 sampling periods obtained by the controller 1002 in the previous step.

[0066] The controller 1002 controls the working state of the fan 1003 by comparing and analyzing the n current pressure values in the n sampling periods and the (n+θ) current pressure values in the (n+θ) sampling periods. For example, the controller 1002 can calculate according to the 10 current pressure values (P1, P2, P3, …, P9, P10) in the 10 sampling periods and the 15 current pressure values (P1, P2, P3, …, P14, P15) in the 15 sampling periods, using a correlation algorithm to determine whether the extractor hood 1000 has oil fume backflow, so as to accurately control the working state of the fan 1003. 10 14 15

[0067] It can be understood that, since high-rise buildings use public chimneys for centralized smoke exhaust, when other households use the extractor hood at the same time, a large amount of oil fume flows into the public chimney, causing the pressure in the chimney to instantaneously increase. If the extractor hood 1000 of the current household has oil fume backflow, the oil fume of the public chimney flows back to the inside of the extractor hood 1000, causing the pressure inside the extractor hood 1000 to increase. Therefore, by calculating using a correlation algorithm, if the (n+θ) current pressure values in the (n+θ) sampling periods increase relative to the n current pressure values in the n sampling periods, it can be determined that the extractor hood 1000 has oil fume backflow.

[0068] Among the 15 current pressure values detected in the 15 sampling periods, the 10 current pressure values detected in the first 10 sampling periods are the same as the 10 current pressure values detected by the pressure sensor 1001 in the 10 sampling periods obtained by the controller 1002 in the previous step. For example, the controller 1002 can calculate according to the 10 current pressure values (P1, P2, P3, …, P9, P10) in the 10 sampling periods and the 15 current pressure values (P1, P2, P3, …, P14, P15) in the 15 sampling periods, using a correlation algorithm to determine whether the extractor hood 1000 has oil fume backflow, so as to accurately control the working state of the fan 1003. 10 14 15 Of course, the correlation algorithm can also be other algorithms, as long as it can accurately determine whether the extractor hood 1000 has oil fume backflow according to the n current pressure values in the n sampling periods and the (n+θ) current pressure values in the (n+θ) sampling periods, and then accurately control the working state of the fan 1003.

[0069] Through comparative analysis, if it is determined that the oil fume backflow exists in the smoke machine 1000, the controller 1002 can send an opening instruction to the fan 1003 to control the fan 1003 to open, and the fan 1003 is started to generate sufficient airflow to offset the backflow pressure, so as to prevent further backflow of external oil fume and discharge the backflow oil fume. After the backflow oil fume of the smoke machine 1000 is discharged, the controller 1002 can send a closing instruction to the fan 1003 to control the smoke machine 1000 to close, and the fan 1003 is stopped to save power consumption.

[0070] In the embodiment of the application, the two groups of pressure data with different cycle spans (n sampling periods and (n+θ) sampling periods) collected by the pressure sensor 1001 are used to realize accurate decision of starting and stopping of the fan 1003, which can effectively solve the problem that single-cycle pressure sampling is easily disturbed by transient airflow, eliminate accidental errors, and significantly improve the reliability of backflow prevention control. The dynamic window is expanded based on the n sampling periods. The expanded cycle data includes the n sampling period data, which not only ensures the continuity of the data, but also introduces the latest pressure change trend.

[0071] Please refer to Figure 3 In some embodiments, before obtaining the n current pressure values detected by the pressure sensor 1001 in n sampling periods, the backflow prevention control method further comprises:

[0072] determining whether the pressure sensor 1001 has a fault;

[0073] when the pressure sensor 1001 has a fault, displaying a fault code to remind the user;

[0074] when the pressure sensor 1001 does not have a fault, entering the step of obtaining the n current pressure values detected by the pressure sensor 1001 in n sampling periods.

[0075] Specifically, after the chip is initialized, before the pressure sensor 1001 samples and detects the current pressure value in the smoke machine 1000, the fault of the pressure sensor 1001 can be determined.

[0076] The fault judgment of the pressure sensor 1001 includes judging whether the communication between the pressure sensor 1001 and the controller 1002 is normal. It can be understood that when the pressure sensor 1001 is not properly inserted (such as physically disconnected) or there is a communication fault (such as a communication protocol mismatch, line interference, etc.), the communication between the pressure sensor 1001 and the controller 1002 will be abnormal, and the controller 1002 will not be able to obtain the current pressure value detected by the pressure sensor 1001 from the sensor. Therefore, in one example, the controller 1002 can send a test instruction to the pressure sensor 1001 to judge whether the communication between the pressure sensor 1001 and the controller 1002 is normal.

[0077] When the communication between the pressure sensor 1001 and the controller 1002 is abnormal, a fault code can be displayed on the control panel of the range hood 1000 to remind the user. For example, when the pressure sensor 1001 is not properly inserted, the control panel of the range hood 1000 can flash a fault code E01; for another example, when the communication protocol between the pressure sensor 1001 and the controller 1002 is not matched, the control panel of the range hood 1000 can display a fault code E02 while making the indicator light flash red and blue alternately. In this way, the problem can be quickly located and the user can be reminded to maintain or replace the pressure sensor 1001.

[0078] Please refer to Figure 3 In some embodiments, the working state of the fan 1003 is controlled according to n current pressure values of n sampling periods and (n+θ) current pressure values of (n+θ) sampling periods, including:

[0079] The pressure average value of n sampling periods is calculated according to n current pressure values of n sampling periods;

[0080] The pressure average value of (n+θ) sampling periods is calculated according to (n+θ) current pressure values of (n+θ) sampling periods;

[0081] The working state of the fan 1003 is controlled according to the pressure average value of n sampling periods and the pressure average value of (n+θ) sampling periods.

[0082] Specifically, the controller 1002 calculates the pressure average value of n sampling periods and the pressure average value of (n+θ) sampling periods Then the working state of the fan 1003 is controlled according to the pressure average value and the pressure average value

[0083] Wherein, the calculation formula of the pressure average value of n sampling periods is as follows: ​

[0084]

[0085] the pressure average value of (n+θ) sampling periods The calculation formula is as follows:

[0086]

[0087] Taking the above n=10 and θ=5 as an example, the controller 1002 calculates the pressure average value of 10 sampling periods and the pressure average value of 15 sampling periods Then, according to the pressure average value and the pressure average value , the working state of the fan 1003 is controlled. For example, directly according to the difference between the pressure average value and the pressure average value , the working state of the fan 1003 is controlled; or, according to the absolute value of the difference between the pressure average value and the pressure average value , the working state of the fan 1003 is controlled; or, according to the proportional relationship between the pressure average value and the pressure average value , the working state of the fan 1003 is controlled, and the like, which are not limited herein.

[0088] In the embodiments of the present application, the arithmetic average values (i.e. and ) with a certain step (i.e. θ) are used for comparative analysis as the judgment condition of the oil fume backflow, and then the working state of the fan 1003 is controlled. In the n sampling periods and the (n+θ) sampling periods, the data error is reduced by the numerical accumulation and average value, the judgment accuracy of the oil fume backflow is improved, the possibility of misjudgment is greatly reduced, and then the working state of the fan 1003 can be accurately controlled to achieve the effect of discharging the backflow oil fume.

[0089] Please refer to Figure 3 In some embodiments, according to the pressure average value of n sampling periods and the pressure average value of (n+θ) sampling periods, the working state of the fan 1003 is controlled, including:

[0090] judging whether the first pressure difference between the pressure average value of (n+θ) sampling periods and the pressure average value of n sampling periods is greater than a first predetermined threshold value;

[0091] When the first pressure difference is greater than the first predetermined threshold value, the fan 1003 is turned on.

[0092] Specifically, the controller 1002 calculates the pressure average value of (n+θ) sampling periods a first pressure difference ΔP1 between the pressure average value of n sampling periods When the first pressure difference ΔP1 is greater than a first predetermined threshold a, the controller 1002 controls the fan 1003 to be turned on (the fan 1003 is turned off before).

[0093] Wherein, the calculation formula of the first pressure difference ΔP1 is as follows:

[0094]

[0095] If ΔP1>a, the fan 1003 is turned on. Taking the foregoing example of n=10 and θ=5, the controller 1002 calculates the pressure average value of 15 sampling periods a first pressure difference ΔP1 between the pressure average value of 10 sampling periods If ΔP1>a, the fan 1003 is turned on.

[0096] It can be understood that if ΔP1≤a, the fan 1003 remains off, and the current pressure value inside the extractor hood 1000 is continuously sampled and detected by the pressure sensor 1001, and then the foregoing steps S10-S30 are executed again.

[0097] It should be noted that the first predetermined threshold a can be a threshold value set by a person in advance, for example, a=20 Pa. Of course, the value of a is not limited to this, and can be obtained through experimental calibration. It only needs to be able to accurately distinguish whether the extractor hood 1000 has oil fume backflow.

[0098] In some examples, the first predetermined threshold a can also be a dynamic threshold and is set by time period. That is, the first predetermined threshold a changes with the change of time period. In the cooking off-peak period, the first predetermined threshold a can be set to be relatively large (for example, 20 Pa); and in the cooking peak period, the first predetermined threshold a can be set to be relatively small (for example, from 20 Pa to 15 Pa), so as to prevent further backflow of external oil fume in the cooking peak period and to discharge the backflow oil fume.

[0099] ​In some examples, the working gears of the fan 1003 include a weak gear (a rotation speed range of, for example, 1200-2200 rpm) and a strong gear (a rotation speed range of, for example, 3200-4500 rpm). When the fan 1003 is controlled to be turned on, the fan 1003 can be controlled to operate in the weak gear. It can be understood that the amount of oil fume backflow of the range hood 1000 is not too much each time, and the weak gear has lower power and smaller noise than the strong gear. Therefore, the fan 1003 operates in the weak gear, which not only prevents further backflow of external oil fume and discharges the backflowing oil fume, but also reduces power consumption and achieves a mute effect. Of course, in other examples, the fan 1003 can also not be limited in working gears when being controlled to be turned on.

[0100] In the embodiments of the present application, the arithmetic mean value (i.e. and ) with a certain step (i.e. θ) is subtracted, and then compared with the first predetermined threshold value a as the judgment condition of oil fume backflow. If the condition is met, the fan 1003 is controlled to be turned on. In the n sampling periods and the (n+θ) sampling periods, the average value obtained by numerical accumulation reduces data error and improves the judgment accuracy of oil fume backflow, greatly reduces the possibility of misjudgment, and then accurately controls the working state of the fan 1003 to achieve the effect of discharging backflowing oil fume.

[0101] Please refer to Figure 4 In some embodiments, in the process of controlling the working state of the fan 1003 according to the n current pressure values in the n sampling periods and the (n+θ) current pressure values in the (n+θ) sampling periods, the backflow prevention control method further comprises:

[0102] obtaining an (n-1)th current pressure value detected by the pressure sensor 1001 in an (n-1)th sampling period;

[0103] obtaining an nth current pressure value detected by the pressure sensor 1001 in an nth sampling period;

[0104] judging whether a second pressure difference between the nth current pressure value in the nth sampling period and the (n-1)th current pressure value in the (n-1)th sampling period is greater than a second predetermined threshold value;

[0105] when the second pressure difference is greater than the second predetermined threshold value, taking the (n-1)th current pressure value in the (n-1)th sampling period as the nth current pressure value in the nth sampling period.

[0106] Specifically, the controller 1002 obtains an (n-1)th current pressure value P (n-1), obtain the nth current pressure value P detected by the pressure sensor 1001 in the nth sampling period n Then, determine the nth current pressure value P n and the (n-1)th current pressure value P (n-1) Is the second pressure difference between the two greater than the second predetermined threshold value b? n -P (n-1) >b, the (n-1)th current pressure value P of the (n-1)th sampling period is (n-1) As the nth current pressure value P in the nth sampling period n , which is used to control the working state of the fan 1003 according to the n current pressure values ​​of n sampling periods and the (n+θ) current pressure values ​​of (n+θ) sampling periods.

[0107] The working process of the anti-backflow control method of the embodiment of the present application is described below with reference to specific examples. Taking n=10 as an example, n-1=9.

[0108] First, the pressure sensor 1001 is initialized. The initialization operation can achieve zeroing processing, zero offset elimination, temperature compensation, etc. of the pressure sensor 1001, thereby ensuring the reliability of subsequent sampling and detection.

[0109] Then, the controller 1002 obtains the 9th current pressure value P9 detected by the pressure sensor 1001 in the 9th sampling period, and obtains the 10th current pressure value P1 detected by the pressure sensor 1001 in the 10th sampling period. 10 Next, determine the 10th current pressure value P 10 Is the second pressure difference between the current pressure value P9 and the 9th current pressure value P9 greater than the second predetermined threshold value b? 10 -P9>b, the 9th current pressure value P9 of the 9th sampling period is used as the 10th current pressure value P of the 10th sampling period. 10 .

[0110] The controller 1002 compares and analyzes the 10 current pressure values ​​(P1, P2, P3, ..., P9, P10, P20, P30, P90 ... 10 ) and 15 current pressure values ​​(P1, P2, P3, ..., P 14 、P 15 ), in the example of controlling the working state of the fan 1003, the 10 current pressure values ​​(P1, P2, P3, ..., P9, P9) of 10 sampling periods are compared and analyzed with the 15 current pressure values ​​(P1, P2, P3, ..., P9) of 15 sampling periods. 14 、P 15), control the working state of the fan 1003.

[0111] It can be understood that the current pressure values obtained in the foregoing steps S10 and S20 can have errors due to various reasons. When the subsequent sampling pressure value changes greatly compared with the previous sampling pressure value, the previous sampling pressure value can be taken as the subsequent sampling pressure value (for example, in the foregoing example, if P9=100 Pa and P 10 =200 Pa, P9 is taken as P 10 for subsequent calculation), so that the large deviation value (i.e., the outlier) in the sampling process of the pressure sensor 1001 can be eliminated, the sampling error is reduced, the subsequent judgment is more accurate, and the frequent opening and closing of the fan 1003 caused by misjudgment is greatly reduced. It should be noted that the outlier elimination scheme of the embodiments of the present application is applicable to the judgment of any current pressure value obtained in the foregoing steps S10 and S20.

[0112] The second predetermined threshold b can be a threshold artificially set in advance, for example, b=50 Pa. Of course, the value of b is not limited to this, and can be obtained through experimental calibration. It only needs to be able to accurately screen out the large deviation value in the sampling process of the pressure sensor 1001.

[0113] Please refer to Figure 3 and Figure 5 In some embodiments, the anti-inverted flow control method further comprises:

[0114] S40: obtaining (n-1) current pressure values detected by the pressure sensor 1001 in (n-1) sampling periods;

[0115] S50: obtaining the nth current pressure value detected by the pressure sensor 1001 in the nth sampling period;

[0116] S60: controlling the working state of the fan 1003 according to the (n-1) current pressure values in the (n-1) sampling periods and the nth current pressure value in the nth sampling period.

[0117] Specifically, the foregoing steps S40-S60 can be executed after the fan 1003 is turned on. That is, the sampling period of the pressure sensor 1001 starts to accumulate again after the fan 1003 is turned on. The controller 1002 obtains (n-1) current pressure values detected by the pressure sensor 1001 in (n-1) sampling periods. Taking n=16 as an example, n-1=15. The controller 1002 obtains 15 current pressure values detected by the pressure sensor 1001 in 15 sampling periods, which can be represented as P1, P2, P3, …, P 14 , P 15 .

[0118] The controller 1002 acquires the nth current pressure value detected by the pressure sensor 1001 in the nth sampling period. Taking n = 16 as an example, the controller 1002 acquires the 16th current pressure value P 16 .

[0119] The controller 1002 controls the working state of the fan 1003 by comparing and analyzing the (n-1) current pressure values in the (n-1) sampling periods and the nth current pressure value in the nth sampling period. For example, the controller 1002 can calculate according to the 15 current pressure values (P1, P2, n3, …, P 14 , P 15 ) in the above-mentioned 15 sampling periods and the 16th current pressure value P 16 in the above-mentioned 16th sampling period by using a correlation algorithm to determine whether the backflow of oil fume in the range hood 1000 has been discharged, so as to accurately control the working state of the fan 1003.

[0120] It can be understood that when the backflow of oil fume in the range hood 1000 has been discharged, the pressure inside the range hood 1000 will tend to be stable. Therefore, by using the correlation algorithm to calculate that the (n-1) current pressure values in the (n-1) sampling periods and the nth current pressure value in the nth sampling period are approximately equal, it can be determined that the backflow of oil fume in the range hood 1000 has been discharged.

[0121] Wherein, the correlation algorithm is, for example, an average value algorithm, a median algorithm, etc., which is not limited here. Taking the average value algorithm as an example, the controller 1002 can control the working state of the fan 1003 by comparing and analyzing the average value of the (n-1) current pressure values in the (n-1) sampling periods and the nth current pressure value in the nth sampling period; taking the median algorithm as an example, the controller 1002 can control the working state of the fan 1003 by comparing and analyzing the median of the (n-1) current pressure values in the (n-1) sampling periods and the nth current pressure value in the nth sampling period. Of course, the correlation algorithm can also be other algorithms, as long as it can accurately determine that the backflow of oil fume in the range hood 1000 has been discharged according to the (n-1) current pressure values in the (n-1) sampling periods and the nth current pressure value in the nth sampling period, and then accurately control the working state of the fan 1003.

[0122] After comparison and analysis, if it is determined that the backflow of oil fume in the range hood 1000 has been discharged, the controller 1002 can send a closing instruction to the fan 1003 to control the range hood 1000 to be closed, and the fan 1003 stops running immediately to save power consumption.

[0123] Please refer to Figure 3In some embodiments, controlling the operating state of the fan 1003 according to the (n-1) current pressure value of the (n-1) sampling period and the nth current pressure value of the nth sampling period includes:

[0124] Calculate the pressure average value of (n-1) sampling periods based on the (n-1) current pressure values ​​of (n-1) sampling periods;

[0125] Determining whether a third pressure difference between an nth current pressure value in an nth sampling period and a pressure average value in an (n-1)th sampling period is less than a third predetermined threshold;

[0126] When the third pressure difference is less than the third predetermined threshold, the fan 1003 is controlled to be turned off.

[0127] Specifically, the controller 1002 calculates the pressure average value of (n-1) sampling cycles Then determine the nth current pressure value P in the nth sampling period n The average pressure of (n-1) sampling periods The third pressure difference ΔP3 between the pressures ΔP1 and ΔP2 is smaller than a third predetermined threshold value c. When the third pressure difference ΔP3 is smaller than the third predetermined threshold value c, the fan 1003 is controlled to be turned off.

[0128] Among them, the average pressure of (n-1) sampling periods The calculation formula is as follows:

[0129]

[0130] The calculation formula of the third pressure difference ΔP3 is as follows:

[0131]

[0132] If ΔP3 < c, the fan 1003 is controlled to be turned off. Taking n = 16 as an example, the controller 1002 calculates the 16th current pressure value P in the 16th sampling period. 16 The pressure average value of 15 sampling cycles The third pressure difference between If ΔP3 < c, the fan 1003 is controlled to be turned off.

[0133] It can be understood that if ΔP3 ≥ c, the fan 1003 is controlled to remain on, and the current pressure value inside the range hood 1000 is continuously sampled and detected through the pressure sensor 1001, and then the aforementioned steps S40 to S60 are executed again.

[0134] It should be noted that the third predetermined threshold c can be a threshold set artificially in advance. In an example, c can be a value close to 0, for example, c = 0.1 pa. Of course, the value of c is not limited thereto, and can be calibrated through experiments, as long as it can accurately distinguish whether the backflow of oil fume of the range hood 1000 has been discharged. In addition, in the above scheme, whether the third pressure difference is less than the third predetermined threshold can also be simplified as judging whether the third pressure difference is equal to 0, that is, judging whether there is

[0135] Based on the above scheme, the anti-backflow control method of the embodiments of the present application has at least the following advantages:

[0136] (1) The oil fume anti-backflow system composed of the pressure sensor 1001, the controller 1002 and the fan 1003 is simple to implement.

[0137] (2) The pressure data sampled and detected by the pressure sensor 1001 is used as the judgment condition of whether the range hood 1000 has backflow of oil fume.

[0138] (3) The large deviation value (i.e. outlier) in the sampling process of the pressure sensor 1001 is eliminated, so that the subsequent judgment is more accurate, and the frequent opening and closing of the fan 1003 caused by misjudgment is greatly reduced.

[0139] (4) The arithmetic mean value (i.e. and ) with a certain step (i.e. θ) is used to make a difference, and then compared with the first predetermined threshold a, as the judgment condition of oil fume backflow, and the condition is true, then the fan 1003 is controlled to be turned on. In the n sampling periods and (n+θ) sampling periods, the average value is obtained by accumulating the values, which reduces the data error, improves the judgment accuracy of oil fume backflow, greatly reduces the possibility of misjudgment, and then accurately controls the working state of the fan 1003, so as to achieve the effect of discharging the backflow of oil fume.

[0140] Please refer to Figure 2 and Figure 6The anti-backflow control device 100 of the embodiment of the present application is applied to a range hood 1000. The range hood 1000 comprises a pressure sensor 1001 and a fan 1003. The pressure sensor 1001 is configured to sample and detect a current pressure value inside the range hood 1000. The anti-backflow control device 100 comprises a first obtaining module 10, a second obtaining module 20 and a control module 30. The first obtaining module 10 is configured to obtain n current pressure values detected by the pressure sensor 1001 in n sampling periods. The second obtaining module 20 is configured to obtain (n+θ) current pressure values detected by the pressure sensor 1001 in (n+θ) sampling periods. The control module 30 is configured to control a working state of the fan 1003 according to the n current pressure values in the n sampling periods and the (n+θ) current pressure values in the (n+θ) sampling periods, wherein n≥1 and θ≥1.

[0141] The anti-backflow control device 100 of the embodiment of the present application can accurately control the working state of the fan 1003 according to the n current pressure values in the n sampling periods and the (n+θ) current pressure values in the (n+θ) sampling periods, so as to achieve the effect of discharging backflowing oil fume.

[0142] In some embodiments, the control module 30 is specifically configured to: calculate a pressure average value of the n sampling periods according to the n current pressure values in the n sampling periods; calculate a pressure average value of the (n+θ) sampling periods according to the (n+θ) current pressure values in the (n+θ) sampling periods; and control the working state of the fan 1003 according to the pressure average value of the n sampling periods and the pressure average value of the (n+θ) sampling periods.

[0143] In the above technical solution, the arithmetic average values (i.e. and ) with a certain step (i.e. θ) are used for comparative analysis as a judgment condition of oil fume backflow, and then the working state of the fan 1003 is controlled. In the n sampling periods and the (n+θ) sampling periods, the average value obtained by numerical accumulation reduces data error, improves the judgment accuracy of oil fume backflow, greatly reduces the possibility of misjudgment, and then the working state of the fan 1003 can be accurately controlled, so as to achieve the effect of discharging backflowing oil fume.

[0144] In some embodiments, the control module 30 is specifically configured to: judge whether a first pressure difference between the pressure average value of the (n+θ) sampling periods and the pressure average value of the n sampling periods is greater than a first predetermined threshold value; and control the fan 1003 to be turned on when the first pressure difference is greater than the first predetermined threshold value.

[0145] In the above technical solution, the arithmetic average values (i.e. and ) is subtracted, and then compared with the first predetermined threshold value a as a judgment condition of the backflow of the oil fume, and if the condition is met, the fan 1003 is controlled to be turned on. In the n sampling periods and the (n+0) sampling periods, the average value obtained by the numerical accumulation reduces the data error, improves the judgment accuracy of the backflow of the oil fume, greatly reduces the possibility of misjudgment, and then accurately controls the working state of the fan 1003 to achieve the effect of discharging the backflow of the oil fume.

[0146] In some embodiments, in the process of controlling the working state of the fan 1003 according to the n current pressure values in the n sampling periods and the (n+0) current pressure values in the (n+0) sampling periods, the control module 30 is further configured to: obtain an (n-1) current pressure value detected by the pressure sensor 1001 in an (n-1) sampling period; obtain an n current pressure value detected by the pressure sensor 1001 in an n sampling period; determine whether a second pressure difference between the n current pressure value in the n sampling period and the (n-1) current pressure value in the (n-1) sampling period is greater than a second predetermined threshold value; and when the second pressure difference is greater than the second predetermined threshold value, take the (n-1) current pressure value in the (n-1) sampling period as the n current pressure value in the n sampling period.

[0147] In the above technical solution, when the next sampling pressure value changes greatly compared with the previous sampling pressure value, the previous sampling pressure value is taken as the next sampling pressure value. In this way, the large deviation value (i.e. the outlier) in the sampling process of the pressure sensor 1001 can be eliminated, the sampling error is reduced, the subsequent judgment is more accurate, and the frequent opening and closing of the fan 1003 caused by misjudgment is greatly reduced.

[0148] In some embodiments, the backflow prevention control device 100 further comprises a third obtaining module and a fourth obtaining module. The third obtaining module is configured to obtain (n-1) current pressure values detected by the pressure sensor 1001 in (n-1) sampling periods. The fourth obtaining module is configured to obtain an n current pressure value detected by the pressure sensor 1001 in an n sampling period. The control module 30 is further configured to control the working state of the fan 1003 according to the (n-1) current pressure values in the (n-1) sampling periods and the n current pressure value in the n sampling period.

[0149] In the above technical solution, by comparing and analyzing the (n-1) current pressure values in the (n-1) sampling periods and the n current pressure value in the n sampling period, a relevant algorithm is used for calculation to determine whether the backflow of the oil fume of the range hood 1000 has been discharged, so as to accurately control the working state of the fan 1003.

[0150] In some embodiments, the control module 30 is specifically configured to: calculate a pressure average value of the (n-1) sampling periods according to (n-1) current pressure values of the (n-1) sampling periods; determine whether a third pressure difference between the nth current pressure value of the nth sampling period and the pressure average value of the (n-1) sampling periods is less than a third predetermined threshold value; and control the fan 1003 to be turned off when the third pressure difference is less than the third predetermined threshold value.

[0151] In the above technical solution, by determining whether the third pressure difference ΔP3 between the nth current pressure value Pn of the nth sampling period and the pressure average value of the (n-1) sampling periods is less than a third predetermined threshold value c, it can be accurately determined whether the backflow of the oil fume of the range hood 1000 has been discharged. If it is determined that the backflow of the oil fume of the range hood 1000 has been discharged, the range hood 1000 is controlled to be turned off to save power consumption. n and the pressure average value of the (n-1) sampling periods In the above technical solution, by determining whether the third pressure difference ΔP3 between the nth current pressure value Pn of the nth sampling period and the pressure average value of the (n-1) sampling periods is less than a third predetermined threshold value c, it can be accurately determined whether the backflow of the oil fume of the range hood 1000 has been discharged. If it is determined that the backflow of the oil fume of the range hood 1000 has been discharged, the range hood 1000 is controlled to be turned off to save power consumption.

[0152] In some embodiments, the backflow prevention control device 100 further comprises a determination module and a prompt module. The determination module is configured to determine whether the pressure sensor 1001 has a fault. The display module is configured to display a fault code to remind a user when the pressure sensor 1001 has the fault. The first acquisition module 10 is configured to acquire n current pressure values detected by the pressure sensor 1001 in n sampling periods when the pressure sensor 1001 does not have the fault.

[0153] In the above technical solution, the pressure sensor 1001 is determined for a fault, and a fault code is displayed to remind a user when the pressure sensor 1001 has the fault, so that the problem can be quickly located and the user is reminded to maintain or replace the pressure sensor 1001.

[0154] It should be noted that the above-mentioned explanation and description of the backflow prevention control method in the foregoing embodiments are also applicable to the backflow prevention control device 100 of the embodiments of the present application, and will not be described here.

[0155] Referring to Figure 7 The backflow prevention control system 200 of the embodiments of the present application comprises one or more processors 210 and a memory 220, and the memory 220 stores a computer program. When the computer program is executed by the processor 210, the backflow prevention control method of any of the above-mentioned embodiments is implemented.

[0156] For example, when the computer program is executed by the processor 210, the following backflow prevention control method is implemented:

[0157] S10: acquiring n current pressure values detected by the pressure sensor 1001 in n sampling periods;

[0158] S20: Obtain (n+θ) current pressure values detected by the pressure sensor 1001 in (n+θ) sampling periods;

[0159] S30: Control the working state of the fan 1003 according to the n current pressure values in n sampling periods and the (n+θ) current pressure values in (n+θ) sampling periods; wherein n≥1, θ≥1.

[0160] For example, when the computer program is executed by the processor 210, the following anti-backflow control method is implemented:

[0161] S40: Obtain (n-1) current pressure values detected by the pressure sensor 1001 in (n-1) sampling periods;

[0162] S50: Obtain the n current pressure value detected by the pressure sensor 1001 in the n sampling period;

[0163] S60: Control the working state of the fan 1003 according to the (n-1) current pressure values in (n-1) sampling periods and the n current pressure value in the n sampling period.

[0164] It should be noted that the above-mentioned anti-backflow control method is also applicable to the anti-backflow control system 200 of the present application, and will not be described here.

[0165] Referring to Figure 8 The computer readable storage medium 300 of the present application stores the computer program 310. When the program is executed by the processor 320, the anti-backflow control method of any of the above-mentioned embodiments is implemented.

[0166] For example, when the program is executed by the processor 320, the following anti-backflow control method is implemented:

[0167] S10: Obtain n current pressure values detected by the pressure sensor 1001 in n sampling periods;

[0168] S20: Obtain (n+θ) current pressure values detected by the pressure sensor 1001 in (n+θ) sampling periods;

[0169] S30: Control the working state of the fan 1003 according to the n current pressure values in n sampling periods and the (n+θ) current pressure values in (n+θ) sampling periods; wherein n≥1, θ≥1.

[0170] For another example, when the program is executed by the processor 320, the following anti-backflow control method is implemented:

[0171] S40: Obtain (n-1) current pressure values detected by the pressure sensor 1001 in (n-1) sampling periods;

[0172] S50: Obtain the n th current pressure value detected by the pressure sensor 1001 in the n th sampling period.

[0173] S60: Control the working state of the fan 1003 according to the (n-1) current pressure values in the (n-1) sampling periods and the n th current pressure value in the n th sampling period.

[0174] It should be noted that the foregoing embodiment of the anti-backflow control method is also applicable to the computer readable storage medium 300 of the embodiment of the application, and will not be described here.

[0175] In summary, the anti-backflow control method, the anti-backflow control device 100, the anti-backflow control system 200 and the computer readable storage medium 300 of the embodiment of the application can accurately control the working state of the fan 1003 according to the n current pressure values in the n sampling periods and the (n+θ) current pressure values in the (n+θ) sampling periods, so as to achieve the effect of discharging backflowing oil fume.

[0176] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0177] Any process or method descriptions in flow charts or described herein in other ways can be understood as representing code modules, segments, or portions of code that include one or more executable instructions for performing specific logic functions or steps in the process. The scope of preferred embodiments of the present application includes the additional implementation in which the functions can be performed in different order, including substantially simultaneously or in reverse order, and the functions can be performed in accordance with the involved functions, which should be understood by those skilled in the art of the embodiments of the present application.

[0178] The logic and / or steps represented in the flow diagrams and / or described herein, for example, can be considered as a sequence of executable instructions, and can be embodied in any computer-readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor- containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this specification, a computer-readable storage medium can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer-readable storage medium can specifically include the following: an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device; a portable computer diskette (magnetic); a random access memory (RAM); a read-only memory (ROM); an erasable programmable read-only memory (EPROM or Flash memory); a portable compact disc read-only memory (CDROM); and a paper tape or other punched tool. Additionally, the computer-readable storage medium can even be paper or another suitable medium upon which the program can be printed, since the program can be electronically captured, for example, via the optical scanning of the paper or other medium, followed by the electronic conversion of the optically scanned program into a machine-executable format. The program thus captured can then be stored in a computer memory.

[0179] It should be understood that various aspects of the application can be implemented in hardware, software, firmware or a combination thereof. In the above embodiments, various steps or methods can be implemented in software or firmware that is stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any of the following technologies, known in the art, or their combinations can be used: discrete logic circuitry having logic gates for implementing logic functions on data signals, application specific integrated circuits having appropriate combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), and the like.

[0180] Those skilled in the art can understand that all or part of the steps of the method carried out by the above-mentioned embodiments can be instructed by a program to complete the relevant hardware, and the program can be stored in a computer readable storage medium. When the program is executed, it includes one of the steps of the method embodiment or a combination thereof. In addition, each functional unit in each embodiment of the present application can be integrated in one processing module, or each unit can exist physically alone, or two or more units can be integrated in one module. The above-mentioned integrated module can be realized in the form of hardware or in the form of software function module. The integrated module, if realized in the form of software function module and sold or used as an independent product, can also be stored in a computer readable storage medium. The above-mentioned storage medium can be a read-only memory, a magnetic disk or an optical disk, etc.

[0181] Although the embodiments of the present application have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and cannot be understood as limiting the present application. Those skilled in the art can make changes, modifications, replacements and variations to the above-mentioned embodiments within the scope of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A backflow prevention control method, characterized in that: Applied to a range hood, the range hood includes a pressure sensor and a fan, the pressure sensor is used to sample and detect the current pressure value inside the range hood, and the anti-backflow control method includes: Obtaining n current pressure values ​​detected by the pressure sensor in n sampling periods; Obtaining (n+θ) current pressure values ​​detected by the pressure sensor in (n+θ) sampling periods; The working state of the fan is controlled according to the n current pressure values ​​of the n sampling periods and the (n+θ) current pressure values ​​of the (n+θ) sampling periods; wherein n≥1 and θ≥1.

2. The backflow prevention control method according to claim 1, characterized in that: The controlling the working state of the fan according to the n current pressure values ​​of the n sampling periods and the (n+θ) current pressure values ​​of the (n+θ) sampling periods includes: Calculating a pressure average value of the n sampling periods according to the n current pressure values ​​of the n sampling periods; Calculating a pressure average value of the (n+θ) sampling periods according to the (n+θ) current pressure values ​​of the (n+θ) sampling periods; The working state of the fan is controlled according to the pressure average value of the n sampling periods and the pressure average value of the (n+θ) sampling periods.

3. The backflow prevention control method according to claim 2, characterized in that: The controlling the working state of the fan according to the pressure average value of the n sampling periods and the pressure average value of the (n+θ) sampling periods includes: Determine whether a first pressure difference between the pressure average value of the (n+θ) sampling periods and the pressure average value of the n sampling periods is greater than a first predetermined threshold; When the first pressure difference is greater than the first predetermined threshold, the fan is controlled to turn on.

4. The backflow prevention control method according to claim 1, characterized in that: In the process of controlling the working state of the fan according to the n current pressure values ​​of the n sampling periods and the (n+θ) current pressure values ​​of the (n+θ) sampling periods, the backflow prevention control method further includes: Obtaining the (n-1)th current pressure value detected by the pressure sensor in the (n-1)th sampling period; Obtaining the nth current pressure value detected by the pressure sensor in the nth sampling period; Determining whether a second pressure difference between the nth current pressure value in the nth sampling period and the (n-1th current pressure value in the (n-1)th sampling period is greater than a second predetermined threshold; When the second pressure difference is greater than the second predetermined threshold, the (n-1)th current pressure value in the (n-1)th sampling period is used as the nth current pressure value in the nth sampling period.

5. The backflow prevention control method according to claim 1, characterized in that: The anti-backflow control method also includes: Obtaining (n-1) current pressure values ​​detected by the pressure sensor in (n-1) sampling periods; Obtaining the nth current pressure value detected by the pressure sensor in the nth sampling period; The working state of the fan is controlled according to the (n-1) current pressure value of the (n-1) sampling period and the nth current pressure value of the nth sampling period.

6. The backflow prevention control method according to claim 5, characterized in that: The controlling the working state of the fan according to the (n-1) current pressure value of the (n-1) sampling period and the nth current pressure value of the nth sampling period includes: Calculating a pressure average value of the (n-1) sampling period according to the (n-1) current pressure values ​​of the (n-1) sampling period; determining whether a third pressure difference between the nth current pressure value in the nth sampling period and the pressure average value in the (n-1)th sampling period is less than a third predetermined threshold; When the third pressure difference is less than the third predetermined threshold, the fan is controlled to be turned off.

7. The backflow prevention control method according to claim 1, characterized in that: Before acquiring the n current pressure values ​​detected by the pressure sensor in n sampling periods, the backflow prevention control method further includes: Determining whether the pressure sensor is faulty; When the pressure sensor fails, a fault code is displayed to alert the user; When the pressure sensor is not faulty, the process proceeds to the step of obtaining n current pressure values ​​detected by the pressure sensor in n sampling periods.

8. A backflow prevention control device, characterized in that: Applied to a range hood, the range hood includes a pressure sensor and a fan, the pressure sensor is used to sample and detect the current pressure value inside the range hood, and the anti-backflow control device includes: A first acquisition module is configured to acquire n current pressure values ​​detected by the pressure sensor in n sampling periods; A second acquisition module is used to obtain (n+θ) current pressure values ​​detected by the pressure sensor in (n+θ) sampling periods; A control module is used to control the working state of the fan according to the n current pressure values ​​of the n sampling periods and the (n+θ) current pressure values ​​of the (n+θ) sampling periods; wherein n≥1, θ≥1.

9. A backflow prevention control system, characterized in that: The backflow prevention control system includes one or more processors and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the backflow prevention control method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the backflow prevention control method according to any one of claims 1 to 7 is implemented.

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