Gas flow detection device in gas pipe and range hood

Abstract

The invention relates to a gas flow detection device in a gas pipe and a range hood, the gas flow detection device in the gas pipe comprises a pipe joint body, the pipe joint body is internally provided with a gas circulation cavity communicated with an inlet and an outlet, and the gas circulation cavity is divided into a nozzle section and a pneumatic acoustic resonant cavity section in the wind direction from the inlet to the outlet; a resonance tube with one end open and the other end closed is arranged in the aeroacoustic resonance cavity section, and a microphone array capable of collecting aeroacoustic signals is attached to the outer wall of the aeroacoustic resonance cavity section of the tube joint body. The signal analysis module is used for obtaining the gas flow Q according to the aerodynamic acoustic signals collected by the microphone array; and the signal sending module is connected with the signal analysis module and used for sending the gas flow Q obtained by the signal analysis module to external equipment. Compared with the prior art, the gas flow measuring device has the advantage that the gas flow in the gas pipe can be measured without intrusive installation.

Description

Technical Field

[0001] The present invention relates to a detection device capable of detecting the gas flow rate and gas components in a gas pipe connected to a stove, and a range hood capable of being linked controlled with the stove. Background Art

[0002] Range hoods are essential appliances for daily cooking and smoke extraction. Combo products with a range hood and stove linkage function have become increasingly popular in recent years. However, existing range hood and stove linkage products have the following drawbacks:

[0003] First, these packaged products often only include the special models of certain manufacturers. Even if users choose range hoods and stoves from the same manufacturer, their choice of combinations will be limited, not to mention that some users have to choose range hoods and stoves from two different manufacturers.

[0004] Second, some products utilize infrared temperature sensors and other detection components installed on range hoods to perform non-contact temperature measurement of pots, burners, and other areas above the stove. These sensors attempt to determine the stove's open or closed status based on temperature changes. However, these infrared temperature sensors currently measure the average temperature of a large area encompassing the stovetop. The localized temperature rise at the moment of opening or closing has little impact on the results. Furthermore, the temperature measured when the pot lid is covered is easily averaged by the surrounding low-temperature area, leading to widespread misjudgment, such as accidental shutdowns and inactions. This can even cause the range hood to shut down mid-cooking, reducing the user experience. Furthermore, the temperature measurement method uses regional temperature changes to infer whether the stove is open or closed to adjust the range hood's status, which inherently lags behind the actual on / off state.

[0005] Therefore, the above-mentioned prior art needs to be further improved. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide a gas flow detection device in a gas pipe in response to the above-mentioned prior art, which can measure the gas flow rate inside the gas pipe without the need for invasive installation.

[0007] The second technical problem to be solved by the present invention is to provide a range hood that can be linked controlled according to the gas flow flowing into the stove in response to the above-mentioned existing technology, and the detection of the gas flow in the gas pipe can measure the gas flow inside the gas pipe without invasive installation.

[0008] The technical solution adopted by the present invention to solve the first technical problem mentioned above is: a gas flow detection device in a gas pipe, characterized in that: it includes a pipe joint body, the two ends of the pipe joint body are respectively an inlet and an outlet, the inlet and the outlet are provided with a connection structure that can be connected to the gas pipe joint, and a gas flow cavity connecting the inlet and the outlet is provided inside the pipe joint body. The gas flow cavity is divided into a nozzle section and an aerodynamic acoustic resonance cavity section from the inlet to the outlet in the wind direction, wherein the inlet of the nozzle section is directly connected to the inlet of the pipe joint body, the outlet of the nozzle section is connected to the inlet of the aerodynamic acoustic resonance cavity section, and the aerodynamic acoustic resonance cavity section is connected to the inlet of the aerodynamic acoustic resonance cavity section. The outlet of the acoustic resonance cavity section is connected to the outlet of the pipe joint body, and the inner diameter of the nozzle section gradually decreases from the inlet to the outlet of the nozzle section; the inner diameter of the inlet of the aeroacoustic resonance cavity section is larger than the inner diameter of the outlet of the nozzle section; a resonance tube with one end open and the other end closed is provided inside the aeroacoustic resonance cavity section, the open end of the resonance tube faces the inlet direction of the resonance cavity section, and the closed end of the resonance tube faces the outlet direction of the resonance cavity section; the outer wall of the aeroacoustic resonance cavity section of the pipe joint body is affixed with a microphone array capable of collecting aeroacoustic signals; in addition, the gas flow detection device in the gas pipe also includes:

[0009] a signal analysis module connected to the signal output end of the microphone array, processing the aeroacoustic signal output by the microphone array, obtaining the excitation frequency generated by the gas resonance in the current aeroacoustic resonance cavity, and obtaining the gas flow rate Q flowing through the gas flow cavity in the pipe joint body based on the excitation frequency;

[0010] The signal sending module is connected to the signal analysis module and is used to send the gas flow Q obtained by the signal analysis module to an external device.

[0011] As an improvement, the signal analysis module obtains the gas flow rate Q flowing through the gas flow cavity in the pipe joint body through the following steps:

[0012] Step 1: first, perform bandpass filtering on the aeroacoustic signal output by the microphone array;

[0013] Step 2: Perform FFT spectrum analysis on the bandpass filtered aeroacoustic signal to obtain the excitation frequency f generated by the combustion gas resonance in the current aeroacoustic resonance cavity;

[0014] Step 3: Subtract the preset excitation frequency f0 from the excitation frequency f generated by the current gas resonance in the aeroacoustic resonance cavity obtained in step 2 to obtain the cavity resonance frequency offset Δf;

[0015] Step 4: Substitute the cavity resonance frequency offset Δf into the following formula to obtain the gas flow rate Q flowing through the gas flow cavity in the pipe joint body: Δf = K*Q 0.7 , where K is a preset constant.

[0016] As another solution, a mapping relationship table between the gas flow rate Q and the cavity resonance frequency offset Δf is pre-set in the signal analysis module; when the signal analysis module receives the aeroacoustic signal output by the microphone array, it first performs band-pass filtering and then performs FFT spectrum analysis to obtain the excitation frequency f generated by the gas resonance in the current aeroacoustic resonance cavity. The excitation frequency f generated by the gas resonance in the current aeroacoustic resonance cavity is subtracted from the preset excitation frequency f0 to obtain the cavity resonance frequency offset Δf. Then, based on the mapping relationship table between the gas flow rate Q and the cavity resonance frequency offset Δf, the gas flow rate Q flowing through the gas flow cavity in the pipe joint body is obtained.

[0017] In a further improvement, the signal analysis module further obtains the combustion efficiency η of the cooker connected to the gas flow detection device in the gas pipe in the following manner:

[0018] The cavity resonance frequency offset Δf sequence is continuously recorded, and the standard deviation σ(Δf) of the cavity resonance frequency offset Δf within the time window T is obtained. The time window T = 10s. Then, the combustion efficiency η of the stove connected to the gas flow detection device in the gas pipe is obtained using the following formula:

[0019]

[0020] where f base is the reference frequency fluctuation under the calibration working condition, which is the preset value;

[0021] If the combustion efficiency η>0.9, the stove is in a high-efficiency combustion state; if 0.9≥η≥0.7, the stove is in a medium-efficiency combustion state, and it is recommended to adjust the stove air door opening; if η<0.7, the stove is in a low-efficiency combustion state, and it is recommended to send an alarm signal to indicate that the stove needs to be cleaned or repaired.

[0022] In a further improvement, the signal analysis module continuously obtains the cavity resonance frequency offset Δf, and outputs a stove flameout alarm signal if the cavity resonance frequency offset Δf drops sharply to a preset environmental noise threshold within a preset time.

[0023] The side wall of the resonance tube is provided with a side wall hole.

[0024] The technical solution adopted by the present invention to solve the second technical problem is as follows: the machine body is further provided with a signal receiving module that can be matched with the signal sending module of the gas flow detection device in the gas pipe described in claim 1 or 2. When the signal receiving module receives the gas flow Q sent by the signal sending module of the gas flow detection device in the gas pipe, the gear position of the fan system is adjusted according to the gas flow Q. The specific control method is:

[0025] If the gas flow rate Q is less than Q a, judging that the current fire power of the stove is low fire power, and adjusting the gear of the fan system to low gear;

[0026] If Q is greater than or equal to Q a Less than or equal to Q b , judging that the current fire power of the stove is medium fire power, and adjusting the gear of the fan system to the medium gear;

[0027] If Q is greater than Q b , judging that the current fire power of the stove is high fire power, adjusting the gear of the fan system to high gear;

[0028] Q a , Q b is a preset constant, and Q a b .

[0029] The signal sending module and the signal receiving module are paired signal communication modules.

[0030] Compared with the existing technology, the advantages of the present invention are: the gas flow detection device in the gas pipe is configured by configuring the gas flow cavity in the pipe joint body as a nozzle section and an aeroacoustic resonance cavity section to form a jet excitation structure and a Helmholtz resonance cavity, and utilizing the characteristic of the gas flow changing the acoustic resonance frequency, a microphone array is attached to the outer wall of the aeroacoustic resonance cavity section to collect aeroacoustic signals, and the collected aeroacoustic signals are processed to obtain the gas flow. This non-invasive installation method does not require drilling holes in the gas pipeline, and the structural reliability is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the installation structure of the gas flow detection device in the gas pipe in an embodiment of the present invention.

[0032] Figure 2 Schematic diagram of the linkage structure of a cooker and a range hood in an embodiment of the present invention. DETAILED DESCRIPTION

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

[0034] This embodiment first provides a gas flow detection device in a gas pipe, which includes:

[0035] ​The pipe joint body 1 has an inlet and an outlet at both ends, and both the inlet and the outlet are provided with a connection structure that can be connected to the gas pipe joint. The pipe joint body 1 is installed at the inlet of the gas main at the bottom of the stove, one end is connected to the external gas pipe joint 5, and the other end is connected to the gas main joint 6 at the bottom of the stove; a gas flow cavity connecting the inlet and the outlet is provided inside the pipe joint body, and the gas flow cavity is divided into a nozzle section 11 and an aerodynamic acoustic resonance cavity section 12 from the inlet to the outlet. The inlet of the nozzle section 11 is directly connected to the inlet of the pipe joint body, the outlet of the nozzle section 11 is connected to the inlet of the aerodynamic acoustic resonance cavity section 12, and the outlet 12 of the aerodynamic acoustic resonance cavity section is connected to the outlet of the pipe joint body. The inner diameter of the nozzle section 11 is 1.3mm. The diameter of the nozzle section 11 gradually decreases from the inlet to the outlet of the nozzle section 11; the inner diameter of the inlet of the aeroacoustic resonance cavity section 12 is larger than the inner diameter of the outlet of the nozzle section; a resonance tube 13 with one end open and the other end closed is provided inside the aeroacoustic resonance cavity section 12, the open end of the resonance tube 13 faces the inlet direction of the resonance cavity section, and the closed end of the resonance tube 13 faces the outlet direction of the resonance cavity section, and a side wall hole 131 is opened on the side wall of the resonance tube 13; the outer wall of the aeroacoustic resonance cavity section of the pipe joint body is affixed with a microphone array 2 capable of collecting aeroacoustic signals; the microphone array 2 includes three microphones evenly distributed on the outer wall of the aeroacoustic resonance cavity section at an interval of 120 degrees, which can eliminate environmental noise interference; in addition, the gas flow detection device in the gas pipe also includes:

[0036] The signal analysis module 3 is connected to the signal output end of the microphone array 2, processes the aeroacoustic signal output by the microphone array, obtains the excitation frequency generated by the gas resonance in the current aeroacoustic resonance cavity, and obtains the gas flow rate Q flowing through the gas flow cavity in the pipe joint body based on the excitation frequency;

[0037] The signal sending module 4 is connected to the signal analysis module and is used to send the gas flow Q obtained by the signal analysis module to an external device.

[0038] When the gas switch of the stove is turned on, the gas (high-pressure gas) is first accelerated to a higher speed through the nozzle section 11 (flow velocity v1→v2, if the area is reduced by half, the speed is increased by 2 times, v1s1=v2s2), forming a turbulent shear layer; the high-speed airflow impacts the closed end of the resonance tube 13 to generate a pressure pulse, which is turned back when encountering resistance and causes lateral deflection of the high-pressure gas and flow field vibration, generating high-frequency oscillating airflow, and part of the airflow enters the annular cavity formed between the resonance tube 13 and the inner wall of the aerodynamic and acoustic resonance cavity section 12 through the side wall hole 131; the annular cavity formed between the resonance tube 13 and the inner wall of the aerodynamic and acoustic resonance cavity section 12 and the resonance tube 13 constitute a coaxial annular composite Helmholtz system; when the gas flow rate Q increases, the jet velocity increases, resulting in an increase in the shear layer instability frequency, causing the cavity resonance frequency to shift.

[0039] In this embodiment, the signal analysis module obtains the gas flow rate Q flowing through the gas flow cavity in the pipe joint body through the following steps:

[0040] Step 1: first, perform bandpass filtering on the aeroacoustic signal output by the microphone array;

[0041] Step 2: Perform FFT spectrum analysis on the bandpass filtered aeroacoustic signal to obtain the excitation frequency f generated by the combustion gas resonance in the current aeroacoustic resonance cavity;

[0042] Step 3: Subtract the preset excitation frequency f0 from the excitation frequency f generated by the current gas resonance in the aeroacoustic resonance cavity obtained in step 2 to obtain the cavity resonance frequency offset Δf;

[0043] Step 4: Substitute the cavity resonance frequency offset Δf into the following formula to obtain the gas flow rate Q flowing through the gas flow cavity in the pipe joint body: Δf = K*Q 0.7 , where K is a preset constant.

[0044] Of course, a mapping relationship table between the gas flow rate Q and the cavity resonance frequency offset Δf can also be pre-set in the signal analysis module; the above step 4 can be replaced by: according to the mapping relationship table between the gas flow rate Q and the cavity resonance frequency offset Δf, obtaining the gas flow rate Q flowing through the gas circulation cavity in the pipe joint body.

[0045] The signal analysis module also obtains the combustion efficiency η of the stove connected to the gas flow detection device in the gas pipe in the following manner:

[0046] The cavity resonance frequency offset Δf sequence is continuously recorded, and the standard deviation σ(Δf) of the cavity resonance frequency offset Δf within the time window T is obtained. The time window T = 10s. Then, the combustion efficiency η of the stove connected to the gas flow detection device in the gas pipe is obtained using the following formula:

[0047]

[0048] where f base is the reference frequency fluctuation under the calibration working condition, which is the preset value;

[0049] If the combustion efficiency η>0.9, the stove is in a high-efficiency combustion state; if 0.9≥η≥0.7, the stove is in a medium-efficiency combustion state, and it is recommended to adjust the stove air door opening; if η<0.7, the stove is in a low-efficiency combustion state, and it is recommended to send an alarm signal to indicate that the stove needs to be cleaned or repaired.

[0050] The signal analysis module continuously obtains the cavity resonance frequency offset Δf, and outputs a stove flameout alarm signal if the cavity resonance frequency offset Δf drops sharply to a preset environmental noise threshold within a preset time.

[0051] The signal analysis module continues to send the combustion efficiency η and the stove flameout alarm signal to the range hood through the signal sending module.

[0052] This embodiment also provides a range hood that can be controlled in conjunction with a stove, comprising a body 101, wherein a fan system 102 is provided in the body 101. Figure 2 As shown, the range hood can be linked with the stove 103 below, and the gas flow detection device in the gas pipe with the above structure is installed on the outer wall of the gas pipe connected to the bottom of the stove 103, one end of which is connected to the external gas pipe connector and the other end is connected to the inlet of the gas main connector at the bottom of the stove; the body 101 is also provided with a signal receiving module 104 that can be matched with the signal sending module 4 of the gas flow detection device in the gas pipe. When the signal receiving module receives the gas flow Q sent by the signal sending module of the gas flow detection device in the gas pipe, the gear position of the fan system is adjusted according to the gas flow Q. The specific control method is as follows:

[0053] If the gas flow rate Q is less than Q a , judging that the current fire power of the stove is low fire power, and adjusting the gear of the fan system to low gear;

[0054] If Q is greater than or equal to Q a Less than or equal to Q b , judging that the current fire power of the stove is medium fire power, and adjusting the gear of the fan system to the medium gear;

[0055] If Q is greater than Q b , judging that the current fire power of the stove is high fire power, adjusting the gear of the fan system to high gear;

[0056] Q a , Q b is a preset constant, and Q a b .

[0057] The signal sending module and the signal receiving module are paired signal communication modules.​

Claims

1. A gas flow detection device in a gas pipe, characterized by: The invention comprises a pipe joint body, wherein the two ends of the pipe joint body are respectively an inlet and an outlet, and the inlet and the outlet are provided with a connection structure that can be connected to the gas pipe joint, and a gas flow cavity connecting the inlet and the outlet is provided inside the pipe joint body, and the gas flow cavity is divided into a nozzle section and an aeroacoustic resonance cavity section from the inlet to the outlet in the wind direction, wherein the inlet of the nozzle section is directly connected to the inlet of the pipe joint body, the outlet of the nozzle section is connected to the inlet of the aeroacoustic resonance cavity section, and the outlet of the aeroacoustic resonance cavity section is connected to the outlet of the pipe joint body, and the inner diameter of the nozzle section gradually decreases from the inlet of the nozzle section to the outlet of the nozzle section; the inner diameter of the inlet of the aeroacoustic resonance cavity section is larger than the inner diameter of the outlet of the nozzle section; a resonance tube with one end open and the other end closed is provided inside the aeroacoustic resonance cavity section, the open end of the resonance tube faces the inlet direction of the resonance cavity section, and the closed end of the resonance tube faces the outlet direction of the resonance cavity section; the pipe joint body is affixed with a microphone array capable of collecting aeroacoustic signals on the outer wall of the aeroacoustic resonance cavity section; in addition, the gas flow detection device in the gas pipe also includes: a signal analysis module connected to the signal output end of the microphone array, processing the aeroacoustic signal output by the microphone array, obtaining the excitation frequency generated by the gas resonance in the current aeroacoustic resonance cavity, and obtaining the gas flow rate Q flowing through the gas flow cavity in the pipe joint body based on the excitation frequency; The signal sending module is connected to the signal analysis module and is used to send the gas flow Q obtained by the signal analysis module to an external device.

2. The gas flow detection device in a gas pipe according to claim 1, characterized in that: The signal analysis module obtains the gas flow rate Q flowing through the gas flow cavity in the pipe joint body through the following steps: Step 1: first, perform bandpass filtering on the aeroacoustic signal output by the microphone array; Step 2: Perform FFT spectrum analysis on the bandpass filtered aeroacoustic signal to obtain the excitation frequency f generated by the combustion gas resonance in the current aeroacoustic resonance cavity; Step 3: Subtract the preset excitation frequency f0 from the excitation frequency f generated by the current gas resonance in the aeroacoustic resonance cavity obtained in step 2 to obtain the cavity resonance frequency offset Δf; Step 4: Substitute the cavity resonance frequency offset Δf into the following formula to obtain the gas flow rate Q flowing through the gas flow cavity in the pipe joint body: Δf = K*Q 0.7 , where K is a preset constant.

3. The gas flow detection device in a gas pipe according to claim 1, characterized in that: The signal analysis module is pre-set with a mapping relationship table between the gas flow rate Q and the cavity resonance frequency offset Δf. When the signal analysis module receives the aeroacoustic signal output by the microphone array, it first performs band-pass filtering and then performs FFT spectrum analysis to obtain the excitation frequency f generated by the gas resonance in the current aeroacoustic resonance cavity. The excitation frequency f generated by the gas resonance in the current aeroacoustic resonance cavity is subtracted from the preset excitation frequency f0 to obtain the cavity resonance frequency offset Δf. Then, based on the mapping relationship table between the gas flow rate Q and the cavity resonance frequency offset Δf, the gas flow rate Q flowing through the gas flow cavity in the pipe joint body is obtained.

4. The gas flow detection device in a gas pipe according to claim 2 or 3, characterized in that: The signal analysis module also obtains the combustion efficiency η of the stove connected to the gas flow detection device in the gas pipe in the following manner: The cavity resonance frequency offset Δf sequence is continuously recorded, and the standard deviation σ(Δf) of the cavity resonance frequency offset Δf within the time window T is obtained. The time window T = 10s. Then, the combustion efficiency η of the stove connected to the gas flow detection device in the gas pipe is obtained using the following formula: where f base is the reference frequency fluctuation under the calibration working condition, which is the preset value; If the combustion efficiency η>0.9, the output stove is in high-efficiency combustion state; If 0.9≥η≥0.7, the stove is in a medium-efficiency combustion state and it is recommended to adjust the stove air door opening; if η<0.7, the stove is in a low-efficiency combustion state and it is recommended to send an alarm signal to indicate that the stove needs to be cleaned or repaired.

5. The gas flow detection device in a gas pipe according to claim 2 or 3, characterized in that: The signal analysis module continuously obtains the cavity resonance frequency offset Δf, and outputs a stove flameout alarm signal if the cavity resonance frequency offset Δf drops sharply to a preset environmental noise threshold within a preset time.

6. The gas flow detection device in a gas pipe according to claim 1, characterized in that: The side wall of the resonance tube is provided with a side wall hole.

7. A range hood comprising a body, a fan system disposed therein, characterized in that: The machine body is further provided with a signal receiving module that can be matched with the signal sending module of the gas flow detection device in the gas pipe according to claim 1 or 2. When the signal receiving module receives the gas flow Q sent by the signal sending module of the gas flow detection device in the gas pipe, the gear position of the fan system is adjusted according to the gas flow Q. The specific control method is: If the gas flow rate Q is less than Q a , judging that the current fire power of the stove is low fire power, and adjusting the gear of the fan system to low gear; If Q is greater than or equal to Q a Less than or equal to Q b , judging that the current fire power of the stove is medium fire power, and adjusting the gear of the fan system to the medium gear; If Q is greater than Q b , judging that the current fire power of the stove is high fire power, adjusting the gear of the fan system to high gear; Q a , Q b is a preset constant, and Q a b .​ 8. The range hood according to claim 7, characterized in that: The signal sending module and the signal receiving module are paired signal communication modules.

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