A public flue fan system and working method

Abstract

The present invention relates to a public flue fan system, comprising an electric control center unit, a plurality of temperature sensors arranged in the flue at intervals along the extending direction of the flue, and a fan arranged at the top of the flue, wherein each temperature sensor and the fan are connected to the electric control center unit by electrical signals. The present invention also relates to a working method of the public flue fan system, wherein when the fan is in a stopped state, the fan is controlled to be turned on according to the temperature rise data of the temperature sensor; and the fan speed is adjusted according to the working current of the fan. And the fan is controlled to be turned off based on the comprehensive conditions of the fan speed, current, and temperature in the flue. The public flue fan system, through its working method, can effectively identify the opening status of the range hood and judge the approximate area position of the start-up range hood, and more accurately adjust the fan speed. And the fan can be controlled to be turned off to reduce energy consumption and working noise.

Description

Technical Field

[0001] The invention relates to a common flue fan system and also to a working method of the common flue fan system. Background Art

[0002] With the development of urbanization, there are more and more high-rise buildings. According to national regulations, high-rise buildings must have public flues for users to exhaust smoke. But the problem that follows is that public flues are often congested, and the most intuitive feeling is that the exhaust effect of indoor range hoods is poor. Usually, an auxiliary exhaust fan system is installed on the top floor to help indoor range hoods exhaust oil smoke. The rooftop fan system is preferably controlled according to the start-up status of the residents' range hoods and the flue environment to achieve energy saving and not disturb the residents. At the same time, the rooftop fan system belongs to the construction of public facilities, which requires a long service life cycle and low maintenance cost. Ideally, the control does not depend on what range hoods the residents use, whether the residents are out of power, etc.

[0003] However, the current public flue fan system has the following problems:

[0004] 1. Continuous operation at high power will cause noise problems, especially for residents living near the top floor. The noise problem is more prominent on quiet nights.

[0005] 2. Continuous operation at low power or high power operation only during fixed time periods cannot meet the pressure requirements of the flue environment, and smoke and odor cross-talk still occurs.

[0006] In order to solve the problem of fixed high power or fixed low power operation of the fan system, the fan system with intelligent control method is applied. The existing intelligent control methods are as follows:

[0007] 1. Wireless communication method:

[0008] A wireless communication terminal module is installed in each household, and the rooftop fan system communicates with the wireless terminal modules of each floor of the residents, detects and senses the activation of the residents' range hoods in real time, and controls the fan air volume according to the activation rate of the residents' range hoods. This method can intelligently adjust the start and stop of the rooftop fan system and the air volume control according to the activation rate of the residents' range hoods. However, this wireless communication method requires that each household user install a wireless communication terminal to detect the user's startup / shutdown information. The disadvantages are obvious. First, it is difficult to implement when the wireless communication terminals on a building are not from the same supplier, and it is only suitable for new residential buildings with all-inclusive fine decoration. Second, the impact and restrictions of maintenance, repair and replacement in the later stage of the product life cycle are relatively large. Changing the manufacturer may cause communication compatibility problems or the purchased range hood may not have a wireless communication terminal. Third, repair and maintenance are difficult: it is impossible to effectively distinguish whether the wireless communication module in the resident's home is damaged or the home power is turned off due to going out, relocation, etc. If the communication module fails, the user cannot perceive it. At this time, the public flue fan system cannot perceive the use of the resident's range hood with a communication failure. If it is not resolved in time, it may cause smoke and odor leakage in the public flue, causing complaints from residents.

[0009] If some residents do not use the wireless terminal module due to replacing the range hood or other reasons, the entire system will fail and the public flue environment will deteriorate.

[0010] 2. Fixed air pressure control method through air pressure sensor:

[0011] By detecting the air pressure inside the public flue outlet, the fan system is intelligently controlled to operate so that the flue outlet is fixed to maintain a certain negative pressure. When no resident uses the range hood, the public flue fan system operates at a lower power to maintain a negative pressure state; when a resident uses the range hood, the pressure in the public flue increases, and the fan system is controlled to increase the air volume, thereby maintaining a fixed negative pressure state. The fan system using this method is always in operation. This control method is difficult to effectively solve the problem of public flue congestion by relying on only a set negative pressure value, because this method cannot make real-time adjustments to the negative pressure according to the user's range hood startup status. In addition, due to the detection accuracy of the wind pressure sensor, this method cannot accurately detect the start-up and operation of a few range hoods (usually less than 3 to 5). Therefore, the fan system is always in operation to maintain a negative pressure state. Therefore, this method usually has energy-saving and noise problems. Summary of the invention

[0012] The first technical problem to be solved by the present invention is to provide a public flue fan system that can detect and identify whether a range hood is turned on in a house, so there is no need to keep the fan system in operation all the time, and can adjust the fan speed in a targeted manner according to the opening status of range hoods at different heights in the house to ensure smooth discharge of oil fumes.

[0013] The second technical problem to be solved by the present invention is to provide a working method of the common flue fan system for the above-mentioned prior art.

[0014] The technical solution adopted by the present invention to solve the above-mentioned first technical problem is: a common flue fan system, including an electric control center unit, characterized in that it also includes a plurality of temperature sensors arranged in the flue at intervals along the extension direction of the flue, and a fan arranged at the top of the flue, and each temperature sensor and fan is electrically connected to the electric control center unit by signals.

[0015] In order to more conveniently obtain the difference between the temperature at the installation position in the flue and the temperature at the air supply port, the temperature sensor located at the bottom is set corresponding to the air supply port at the bottom of the flue.

[0016] Preferably, the uppermost temperature sensor is arranged in the top of the flue.

[0017] In order to facilitate the realization of each temperature sensor, a communication line is provided through the flue, the communication line is electrically connected to the electric control center unit, and each temperature sensor is electrically connected to the communication line.

[0018] In order to facilitate the fixing of the communication line, avoid the communication line from being damaged due to pulling, and increase the service life of the communication line, a cable is also arranged in the flue, and the communication line is fixed on the cable by a fixing piece.

[0019] In order to facilitate straightening the cable, avoid cable entanglement, and improve the convenience of fixing the communication line, a counterweight block is connected to the lower end of the cable.

[0020] In order to facilitate communication with an external control center and remote management, a wireless communication module connected to the electrical signal of the electric control center unit is also included.

[0021] A working method of the common flue fan system as described above, characterized in that: when the fan is in a stopped state, the temperature data of each temperature sensor is obtained respectively, the temperature rise data of each temperature sensor is calculated, and if the temperature rise data of at least one temperature sensor is greater than a preset temperature rise threshold, the fan is controlled to be turned on;

[0022] Determine the user's range hood opening status according to the temperature data detected in real time by each temperature sensor, and then determine the fan speed F according to the range hood opening status;

[0023] During the operation of the fan, for the current fan speed F, calculate the current change ΔI=I-I0 of the fan operating current I under the current environmental state relative to the fan operating current I0 at zero wind pressure, and judge the relative air pressure inside and outside the current flue according to ΔI, and then adjust the fan speed according to the relative air pressure;

[0024] If the current fan speed V is in the set low speed range, ΔI meets the relative change requirements, and the maximum temperature difference |ΔTmax| between the temperature detected by each temperature sensor and the temperature at the flue air supply port is less than the set shutdown temperature threshold, the fan is controlled to shut down.

[0025] In order to be able to adaptively adjust the fan speed at different speeds of the range hood, when ΔI < 0, it is judged that the current air pressure in the flue is greater than the atmospheric pressure outside the flue; if ΔI > 0, it is judged that the current air pressure in the flue is less than the atmospheric pressure outside the flue;

[0026] When |ΔI|>Im, where Im is the set current difference threshold, Im>0; if ΔI<0, the fan speed is increased according to the set speed adjustment amount until |ΔI|≤Im; if ΔI>0, the fan speed is reduced according to the set speed adjustment amount until |ΔI|≤Im;

[0027] If the current fan speed V is in the set low speed range, |ΔI|≤Im, and the maximum temperature difference |ΔTmax| between the temperature detected by each temperature sensor and the temperature at the flue air supply port is less than the set shutdown temperature threshold, the fan is controlled to shut down.

[0028] In order to better correct the fan speed to match the oil smoke conditions in the flue, on the basis of |ΔI|≤Im, when the maximum temperature difference |ΔTmax| between the temperature detected by each temperature sensor and the temperature at the flue air supply port is greater than the set temperature difference threshold ΔT0, ΔT0>0℃, the fan speed is controlled and adjusted.

[0029] Preferably, if ΔTmax>ΔT0, the fan speed is increased according to the set speed adjustment amount; if ΔTmax<-ΔT0, the fan speed is decreased according to the set speed adjustment amount.

[0030] For the convenience of data processing, from bottom to top, each temperature sensor is recorded as S0, S1, S2, ..., Si, ..., Sn; the real-time temperature data of each corresponding temperature sensor is T0, T1, T2, ..., Ti, ..., Tn, where i and n are positive integers, 1≤i≤n, and n is the total number of temperature sensors located above the temperature sensor S0; Ti represents the temperature data of the temperature sensor at the i-th position arranged above the temperature sensor S0 from bottom to top;

[0031] Compare the current temperature data Ti of each temperature sensor with the previously detected temperature data T0i, and then calculate the temperature change ΔTi of each temperature sensor detection point;

[0032] If the temperature data detected three times in a row at a temperature sensor position satisfies ΔTi>k, where k is a preset temperature rise data, it is determined that the temperature rise data of the temperature sensor is greater than a preset temperature rise threshold.

[0033] In order to facilitate the determination of the area where the range hood is turned on, after the fan is turned on, while obtaining the real-time temperature data of the temperature sensor, the temperature data of the adjacent temperature sensors are compared. If Ti>Ti-1, it is determined that the range hood is turned on in the area between the distribution positions of the temperature sensors Si-1 and Si; the fan speed is determined accordingly.

[0034] Where h is the distance between the temperature sensor Si and the top of the flue; H is the total length of the flue; Y i is the fan speed sound box factor at the temperature sensor Si position, R i It is the standard speed of the fan of the range hood at the temperature sensor Si under the set standard air volume working condition.

[0035] Compared with the prior art, the advantages of the present invention are: the common flue fan system, through its working method, uses the detection data of the temperature sensor to determine the temperature condition in the flue, thereby effectively identifying the opening condition of the range hood and determining the approximate area location of the start-up range hood, and after the fan is started, the fan speed can be adjusted according to the temperature condition in the flue, thereby being able to more specifically adjust the fan speed to match the oil smoke condition in the flue. In addition, it can also determine the situation where the fan does not need to work, and reduce the fan energy consumption and working noise when the fan does not need to work. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the structure of a common flue fan system in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below with reference to the accompanying drawings.

[0038] After the range hood 8 of the user's home is turned on, as the oil smoke enters the public flue, the temperature in the public flue corresponding to the connection point between the resident's home and the public flue will rise. Generally, the more oil smoke there is, the more high-temperature gas there is, and the faster the temperature rises. Under the action of air pressure and hot air, the hot air entering the public flue moves / diffuses toward the top of the public flue at a certain speed. Therefore, the air temperature in the public flue is correlated with the opening status of the range hood 8 of each household in the house and the working status of the oil smoke extraction.

[0039] Based on this correlation, the present application designs a common flue fan system. Figure 1 As shown, the public flue fan system in this embodiment includes an electric control center unit 1, a plurality of temperature sensors 2 arranged in the flue at intervals along the extension direction of the flue, and a fan 3 arranged at the top of the flue. In order to facilitate maintenance, the electric control center unit 1 is usually arranged next to the fan 3 at the top of the flue, which is also convenient for the fan 3 to be connected. At the same time, in order to facilitate the communication between the public flue fan system and the external control center and facilitate remote management, a wireless communication module connected to the electric control center unit 1 by electrical signals is also provided. The wireless communication module 7 can adopt various wireless communication modules 7 in the prior art. For example, when the public flue fan system is applied to each residence in a community, the corresponding control center is the entire control center of the community, and the control center can obtain the working information of the public flue fan system on each residence.

[0040] Each temperature sensor 2 and fan 3 is also electrically connected to the electric control center unit 1. Each temperature sensor 2 transmits the detected temperature data to the electric control center, and the electric control center can calculate and analyze the temperature data to control the working parameters of the fan 3.

[0041] In this embodiment, the temperature sensor 2 located at the bottom corresponds to the air supply port at the bottom of the flue, so that the temperature sensor 2 can obtain temperature data of the air close to the air supply port. The temperature sensor 2 located at the top is set at the top of the flue. The remaining temperature sensors 2 are distributed between these two temperature sensors 2, that is, distributed in the connection position distribution area of ​​each user's range hood 8 exhaust pipe and the flue, which can more accurately obtain the use of each user's range hood 8.

[0042] In order to facilitate the information communication between each range hood 8 and the control center unit, a communication line 4 is arranged throughout the flue, and the communication line 4 is electrically connected to the electric control center unit 1, and each temperature sensor 2 is electrically connected to the communication line 4. In order to ensure the service life of the communication line 4 and avoid pulling the communication line 4, a cable 5 is also arranged in the flue, and the communication line 4 is fixed to the cable 5 by a fixing member 51. The fixing member 51 can be various existing fixing devices such as a strap. The support of the communication line 4 by the cable 5 greatly reduces the possibility of damage to the communication line 4. In addition, a counterweight block 6 is connected to the lower end of the cable 5. Under the action of the gravity of the counterweight block 6, the cable 5 is basically straightened to avoid the difficulty of fixing and repairing the communication line 4 caused by the entanglement of the cable 5.

[0043] The working method of the aforementioned common flue fan system includes the following steps.

[0044] Step 1, initialization, from bottom to top, each temperature sensor 2 is recorded as S0, S1, S2, ..., Si, ..., Sn. The real-time temperature data of each corresponding temperature sensor 2 is T0, T1, T2, ..., Ti, ..., Tn, where i and n are positive integers, 1≤i≤n, n is the total number of temperature sensors 2 located above the temperature sensor 2S0; Ti represents the temperature data of the temperature sensor 2 at the i-th position arranged from bottom to top above the temperature sensor 2S0.

[0045] Step 2: When the fan 3 is in the shutdown state, the temperature data of each temperature sensor 2 is obtained respectively, and the temperature rise data of each temperature sensor 2 is calculated. Each temperature sensor 2 samples the temperature data according to a fixed sampling period. The temperature rise data of the temperature sensor 2 refers to the change of the current temperature data relative to the previously detected temperature data.

[0046] If the temperature rise data of at least one temperature sensor 2 is greater than the preset temperature rise threshold, it means that the range hood 8 is turned on in the flue, resulting in temperature changes. At this time, the control is to turn on the fan 3. When the fan 3 is turned on, it can be started at the set start speed or at the speed F described below.

[0047] When the temperature data of a temperature sensor 2 at the current sampling moment is greater than k relative to the temperature data at the previous sampling moment, the previous sampling moment is defined as t0, the current sampling moment is defined as t1, and the subsequent sampling moments are t1, t2, and t3 respectively, and t0-1 is the sampling moment of the previous cycle relative to t0, and t0-x represents the sampling moment of the previous x cycles relative to t0.

[0048] In this embodiment, the current temperature data Ti of each temperature sensor 2 is compared with the temperature data T0i previously detected by the corresponding temperature sensor 2, and then the temperature change ΔTi of the detection point of each temperature sensor 2 is calculated. In this embodiment, ΔTi=(T t0 +T t0-1 +T t0-2 +T t0-3 +T t0-4 ) / 5. T t0 When T represents the temperature data sampled by the temperature sensor 2Si at time t0, t0-1 、T t0-2 、T t0-3 、T t0-4 The temperature data collected by the temperature sensor 2Si at the time t0-1, t0-2, t0-3, and t0-4 are shown in sequence.

[0049] If the temperature data detected by a temperature sensor 2 three times in a row starting from time t1 satisfies ΔTi>k, that is, the corresponding temperature data at time t2 and time t3 also satisfies ΔTi>k, where k is the preset temperature rise data, then it is judged that the temperature rise data of the temperature sensor 2 is greater than the preset temperature rise threshold. K is reasonably set according to experiments.

[0050] Step 3: After the fan 3 is turned on, the user's range hood 8 is turned on according to the temperature data detected in real time by each temperature sensor 2, and then the rotation speed F of the fan 3 is determined according to the turning on status of the range hood 8.

[0051] In the flue, based on the principle of temperature attenuation, when the range hood 8 is not turned on in a certain area, the temperature of the upper part of the area must be lower than that of the lower part. Based on this, while obtaining the real-time temperature data of the temperature sensor 2, the temperature data of the adjacent temperature sensors 2 are compared. If Ti>Ti-1, it is determined that the range hood 8 is turned on in the area between the distribution positions of the temperature sensors 2Si-1 and Si, and the speed of the fan 3 is determined accordingly.

[0052] Where h is the distance between the temperature sensor 2Si and the top of the flue; H is the total length of the flue; Y i is the fan 3 speed sound box factor at the temperature sensor 2Si location, R i It is the standard speed of the fan 3 of the range hood 8 at the temperature sensor 2Si under the set standard air volume working condition.

[0053] This step is only a rough calculation of the matching speed of the fan 3 based on the approximate situation of the range hoods in different areas of the flue. The influence of the specific working gear and air volume of the range hood 8 on the working speed of the fan 3 can be further accurately adjusted through step 4.

[0054] Step 4, during the operation of the fan 3, for the current speed F of the fan 3, calculate the current change ΔI=I-I0 of the working current I of the fan 3 under the current environmental state relative to the working current I0 of the fan 3 at zero wind pressure, and judge the relative air pressure inside and outside the current flue according to ΔI, and then adjust the speed of the fan 3 according to the relative air pressure.

[0055] When ΔI<0, it is judged that the current air pressure in the flue is greater than the atmospheric pressure outside the flue; if ΔI>0, it is judged that the current air pressure in the flue is less than the atmospheric pressure outside the flue. However, it is necessary to further judge whether ΔI is within a reasonable fluctuation range, so ΔI is compared with the set current difference threshold.

[0056] When |ΔI|>Im, it is determined that ΔI has exceeded the reasonable fluctuation range, and the current difference is caused by the specific working conditions of the range hood 8, where Im is the set current difference threshold, and Im>0. At this time, if ΔI<0, the speed of the fan 3 is increased according to the set speed adjustment amount until |ΔI|≤Im; if ΔI>0, the speed of the fan 3 is reduced according to the set speed adjustment amount until |ΔI|≤Im. The set speed adjustment amount in this step is 10% of the current speed.

[0057] Step 5: On the basis of step 4, that is, when the speed of the fan 3 is adjusted to satisfy the condition of |ΔI|≤Im, the temperature detected by each temperature sensor 2 is compared with the temperature at the flue air supply port. Since the temperature detected by the temperature sensor 2 is close to the temperature at the flue air supply port, the comparison calculation is to compare Ti with T0.

[0058] When the maximum temperature difference |ΔTmax| between the temperature detected by each temperature sensor 2 and the temperature at the position of the flue air supply port is greater than the set temperature difference threshold ΔT0, it is determined that there is congestion at the corresponding position in the flue, and the speed of the fan 3 is controlled to alleviate the congestion. In this embodiment, ΔT0>0°C, specifically, ΔT0=5°C.

[0059] If ΔTmax>ΔT0, the control increases the speed of the fan 3 according to the set speed adjustment amount until it reaches the maximum speed limit; if ΔTmax<-ΔT0, the control decreases the speed of the fan 3 according to the set speed adjustment amount until it reaches the minimum speed limit. The set speed adjustment amount in this step is 10% of the current speed.

[0060] Step 6. If the current real-time speed V of the fan 3 is in the set low speed range, the low speed range is initialized according to the previous experiments. ΔI meets the relative change requirement, that is, |ΔI|≤Im. And when the maximum temperature difference |ΔTmax| between the temperature detected by each temperature sensor 2 and the temperature at the flue air supply port is less than the set shutdown temperature threshold, it means that the temperature in the flue does not change much, and the speed of the fan 3 is continuously stable and low. At this time, it is judged that no user turns on the range hood 8 or the number of turned-on range hoods 8 is very small and the exhaust volume can be ignored. At this time, the fan 3 is controlled to shut down, which reduces energy consumption on the one hand and reduces working noise on the other hand, making it more user-friendly.

[0061] The public flue fan system, through its working method, uses the detection data of the temperature sensor 2 to determine the temperature condition in the flue, thereby effectively identifying the opening condition of the range hood 8 and determining the approximate area location of the start-up range hood 8. After the fan 3 is started, the speed of the fan 3 can be adjusted according to the temperature condition in the flue, thereby being able to more specifically adjust the speed of the fan 3 to match the oil smoke condition in the flue. In addition, it can also determine the situation where the fan 3 does not need to work, and reduce the energy consumption and working noise of the fan 3 when the fan 3 does not need to work. In addition, the public flue fan system does not involve communication problems with the user's range hood 8, and has no requirements for the type of the user's range hood 8.

Claims

1. A working method of a common flue fan system, characterized in that: The common flue fan system comprises an electric control center unit (1), a plurality of temperature sensors (2) arranged in the flue at intervals along the extending direction of the flue, and a fan (3) arranged at the top of the flue, wherein each temperature sensor (2) and fan (3) is electrically connected to the electric control center unit (1); The temperature sensor (2) located at the bottom is arranged corresponding to the air supply port at the bottom of the flue; the temperature sensor (2) located at the top is arranged in the top of the flue; A communication line (4) is provided through the flue, the communication line (4) is electrically connected to the electric control center unit (1), and each temperature sensor (2) is electrically connected to the communication line (4); A cable (5) is also provided in the flue, and the communication line (4) is fixed to the cable (5) via a fixing member (51); a counterweight (6) is connected to the lower end of the cable (5); It also includes a wireless communication module (7) connected to the electric control center unit (1) via an electrical signal; When the fan (3) is in a stopped state, temperature data of each temperature sensor (2) is obtained respectively, and temperature rise data of each temperature sensor (2) is calculated; if the temperature rise data of at least one temperature sensor (2) is greater than a preset temperature rise threshold, the fan (3) is controlled to be turned on; Determining the activation status of the user's range hood (8) based on the temperature data detected in real time by each temperature sensor (2), and then determining the rotation speed F of the fan (3) based on the activation status of the range hood (8); During the operation of the fan (3), for the current fan (3) speed F, the current change ΔI=I-I0 of the fan (3) operating current I under the current environmental state relative to the fan (3) operating current I0 at zero wind pressure is calculated, and the current relative air pressure inside and outside the flue is determined based on ΔI, and the fan (3) speed is then adjusted based on the relative air pressure. If the current speed V of the fan (3) is in the set low speed range, ΔI meets the relative change requirement, and the maximum temperature difference |ΔTmax| between the temperature detected by each temperature sensor (2) and the temperature at the flue air supply port is less than the set shutdown temperature threshold, the fan (3) is controlled to shut down; When ΔI<0, it is judged that the current air pressure in the flue is greater than the atmospheric pressure outside the flue; if ΔI>0, it is judged that the current air pressure in the flue is less than the atmospheric pressure outside the flue; When |ΔI|>Im, wherein Im is the set current difference threshold value, and Im>0; if ΔI<0, the speed of the fan (3) is increased according to the set speed adjustment amount until |ΔI|≤Im; if ΔI>0, the speed of the fan (3) is decreased according to the set speed adjustment amount until |ΔI|≤Im; If the current speed V of the fan (3) is in a set low speed range, |ΔI|≤Im, and the maximum temperature difference |ΔTmax| between the temperature detected by each temperature sensor (2) and the temperature at the flue air supply port is less than a set shutdown temperature threshold, the fan (3) is controlled to shut down; On the basis of |ΔI|≤Im, when the maximum temperature difference |ΔTmax| between the temperature detected by each temperature sensor (2) and the temperature at the flue air supply port is greater than a set temperature difference threshold value ΔT0, ΔT0>0°C, the speed of the fan (3) is controlled and adjusted.

2. The working method of the common flue fan system according to claim 1, characterized in that: If ΔTmax>ΔT0, the control increases the speed of the fan (3) according to the set speed adjustment amount; if ΔTmax<-ΔT0, the control decreases the speed of the fan (3) according to the set speed adjustment amount.

3. The working method of the common flue fan system according to claim 1, characterized in that: From bottom to top, each temperature sensor (2) is denoted as S0, S1, S2, ..., Si, ..., Sn; the real-time temperature data of each corresponding temperature sensor (2) is T0, T1, T2, ..., Ti, ..., Tn, wherein i and n are positive integers, 1≤i≤n, and n is the total number of temperature sensors (2) located above the temperature sensor (2) S0; Ti represents the temperature data of the temperature sensor (2) at the i-th position arranged from bottom to top above the temperature sensor (2) S0; Compare the current temperature data Ti of each temperature sensor (2) with the previously detected temperature data T0i, and then calculate the temperature change ΔTi of the detection point of each temperature sensor (2); If the temperature data detected three times in succession at a temperature sensor (2) position satisfies ΔTi>k, where k is a preset temperature rise data, it is determined that the temperature rise data of the temperature sensor (2) is greater than a preset temperature rise threshold.

4. The working method of the common flue fan system according to claim 3, characterized in that: After the fan (3) is turned on, the real-time temperature data of the temperature sensor (2) is obtained and the temperature data of the adjacent temperature sensors (2) are compared. If Ti>Ti-1, it is determined that the range hood is turned on in the area between the distribution positions of Si-1 and Si of the temperature sensors (2); the speed of the fan (3) is determined accordingly. ; Where h is the distance between the temperature sensor (2) Si and the top of the flue; H is the total length of the flue; Y i is the fan (3) speed factor at the temperature sensor (2) Si position, R i It is the standard speed of the fan (3) of the range hood at the temperature sensor (2) Si under the set standard air volume working condition.

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