Electronic nose with dual-channel T-pin patch multiplexing gas chamber and reversible process gas path

Abstract

The present invention discloses an electronic nose having a dual-path T-shaped pin patch multiplexing gas chamber and a reversible process gas path. The dual-path T-shaped pin patch multiplexing gas chamber includes a patch shell and a pin cover that are connected to each other to form an air chamber. The patch shell includes a bottom plate and an air wall. An inlet and an outlet are provided at both ends of the air wall. A position for arranging a patch gas sensor array is provided on the inner surface of the bottom plate. The pin cover is provided with an array of mounting holes for fixing the pin gas sensor array. A T-shaped baffle is provided at the bottom edge and the middle of the pin cover, and the horizontal plate of the T-shaped baffle is close to the outlet.

Description

Technical Field

[0001] The present invention relates to the field of gas detection, and in particular to technical fields related to the structural design of gas paths and gas chambers of gas detection devices. Background Art

[0002] Gas / odor, as a key property of matter, is often used as a key indicator to identify certain compounds. In the food industry, odor can be used to monitor the food production process, ensuring the freshness of raw materials and food safety. In environmental monitoring, changes in gas can be used to analyze water quality and understand the degree of water pollution. It can also determine the type of gas in hazardous environments, thereby helping to reduce the occurrence of disasters. Gas detection and identification technology is now required in an increasing number of scenarios.

[0003] Common gas detection methods can be categorized as chemical analysis, instrumental analysis, and sensor technology. Chemical analysis can be divided into absorption and combustion, while instrumental analysis can be divided into spectral analysis and chromatographic analysis. An electronic nose is an instrument composed of a combination of multiple sensors that can detect the types of gases in the environment by embedding appropriate algorithms. The gas path and chamber system are crucial components of the electronic nose, primarily consisting of a solenoid valve, air pump, air pipe, and air chamber. The gas path formed by the solenoid valve, air pump, and air pipe controls the flow of gas within the electronic nose. Opening and closing the solenoid valve effectively switches the gas path, enabling gas collection and cleaning of the gas path and chamber. The gas path and chamber together determine the manner, degree, and effectiveness of contact between the gas and the sensor array, which directly impacts gas identification performance. Summary of the Invention

[0004] Since the gases to be measured in real situations are often not of a single type, the purpose of the present invention is to provide a novel electronic nose air path and air chamber structure that, while ensuring full contact between the measured gas and the sensor, reduces or eliminates the impact of residual gas in the air path on the accuracy and stability of the recognition results. The technical solution of the present invention is as follows:

[0005] An electronic nose having a dual-channel T-shaped pin patch multiplexing gas chamber and a reversible process gas path. The dual-channel T-shaped pin patch multiplexing gas chamber includes a patch shell and a pin cover that are connected to each other to form an air chamber. The patch shell includes a bottom plate and an air wall. An inlet and an outlet are provided at both ends of the air wall. A position for arranging a patch gas sensor array is provided on the inner surface of the bottom plate. The pin cover is provided with an array of mounting holes for fixing the pin gas sensor array. A T-shaped baffle is provided on the bottom edge and the middle of the pin cover, and the horizontal plate of the T-shaped baffle is close to the outlet.

[0006] Furthermore, the reversible process gas circuit includes an inlet, a gas outlet 1, a gas outlet 2, three normally closed three-way solenoid valves, a normally closed two-way solenoid valve, two three-way connectors, and an air pump. The two three-way connectors are respectively referred to as the first and second three-way connectors; according to the control law of the three-way solenoid valve, the gas ports 1 and 2 of the normally closed three-way solenoid valve are connected, and the gas ports 1 and 3 are connected after receiving the control signal. The three normally closed three-way solenoid valves are respectively referred to as the first, second, and third three-way solenoid valves, and the normally closed two-way solenoid valve is cut off and connected after receiving the control signal; wherein,

[0007] The air pump is connected between port 2 of the first three-way solenoid valve and port 1 of the second three-way solenoid valve, and port 2 of the second three-way solenoid valve is connected to the air outlet 2;

[0008] Both ends of the normally closed two-way solenoid valve are connected to one port of the first and second three-way connectors respectively;

[0009] The other two ports of the second three-way connector, one is connected to port 3 of the second three-way solenoid valve, and the other is connected to the inlet of the air chamber;

[0010] The injection port and port 1 of the first three-way solenoid valve are respectively connected to the other two ports of the first three-way connector;

[0011] The outlet 3 of the air chamber is connected to the port 2 of the third three-way solenoid valve, the port 1 of the third three-way solenoid valve is connected to the air outlet 1, and the port 3 of the third three-way solenoid valve is connected to the port 3 of the first three-way solenoid valve.

[0012] Furthermore, when the electronic nose operates in the gas collection mode, the air pump is located between the sampling port and the gas chamber. For the gas to be tested, a pumping method is adopted, and for the gas chamber, a pump blowing method is adopted to send the gas into the gas chamber, so as to ensure that the gas is in full contact with the sensor array in the gas chamber; the working mode is selected by the controller, and a control signal is sent. The gas to be tested enters from the sampling port, and the first three-way solenoid valve 1 and 2 gas ports are controlled to be connected, and the 3rd port is cut off; the second three-way solenoid valve 1 and 3 gas ports are connected, and the 2nd port is cut off; the third three-way solenoid valve 1 and 2 gas ports are connected, and the 3rd port is cut off; the two-way solenoid valve is a normally closed type, is not controlled, and maintains the original state; the air pump working time is controlled by PWM, and the gas to be tested is sent into the gas chamber to contact with the sensor, and is discharged from the air pipe of the outlet 1.

[0013] Furthermore, when the electronic nose operates in the air chamber cleaning mode, the air pump is located between the air chamber and the air outlet 2, and clean air is sucked into the air chamber by pumping to achieve air chamber cleaning. The working mode is selected by the controller, and a control signal is sent. Clean air enters from the air outlet 1 of the "reverse process", and the third three-way solenoid valve 1 and 2 air ports are controlled to be connected, and the 3rd port is blocked; the first three-way solenoid valve 1 and 2 air ports are connected, and the 3rd port is blocked; the second three-way solenoid valve 1 and 2 air ports are connected, and the 3rd port is blocked. The air pump working time is controlled by PWM, so that clean air can fully flow through the air chamber to achieve the purpose of cleaning the air chamber, and the air is discharged from the air outlet 2.

[0014] Furthermore, when the electronic nose operates in the gas path cleaning mode, the air pump is located between the gas outlet 1 and the sample inlet, and uses a pumping method to continuously inhale sufficient clean air to clean the remaining pipes with residual gas to be tested. The working mode is selected by the controller, and a control signal is sent. Clean air enters from the gas outlet 1 of the "reverse process" to control the third three-way solenoid valve 1 and 3 gas ports to be connected, and port 2 to be closed; the normally closed two-way solenoid valve is turned on; the first three-way solenoid valve 1 and 3 gas ports are connected, and port 2 is closed; the second three-way solenoid valve 1 and 3 gas ports are connected, and port 2 is closed; the air pump working time is controlled by PWM to allow clean air to fully flow through the air pipe to achieve the purpose of cleaning the gas path, and the air is discharged from the sample inlet air pipe of the "reverse process".

[0015] The essential features of this invention are: 1) by designing a novel biomimetic air chamber, turbulent airflow is generated at the sensor array to improve the contact reaction quality between the gas to be measured and the gas sensor array; 2) rapid cleaning of each section of the gas path is achieved; 3) single-direction air extraction is always maintained in all cleaning modes, reducing the size of the equipment and the high cost of multiple air pumps; 4) the air chamber and the air inlet pipe are cleaned separately during the cleaning process to ensure high-quality cleaning results. The beneficial effects of this invention are as follows:

[0016] (1) The proposed dual-channel T-pin patch multiplexing air chamber structure can obtain as much sample information as possible while maintaining a small volume.

[0017] (2) To address the problem that the front-end sampling tube of the traditional gas circuit is not involved in the cleaning, the structure designed by the present invention can achieve the "reverse process" of the collection process in the gas tube cleaning mode, thereby effectively cleaning the front-end gas tube. At the same time, after the gas tube cleaning is completed, the solenoid valve can be reset to continue the collection task.

[0018] (3) A three-mode gas path structure is proposed, which can switch between different gas paths according to needs, and has multiple functions such as gas collection, air chamber cleaning, and air pipe cleaning. In addition, due to the different types of materials of the air chamber and air pipe, the cleaning time required for the two is inconsistent, and the residual gas is cross-contaminated. To address this problem, the present invention implements air chamber cleaning and air pipe cleaning separately, reducing the cross-contamination between the residual gases.

[0019] (4) In the present invention, the air pump of the air circuit system always takes in air in one direction in the three modes, which is convenient for the implementation of the control algorithm. At the same time, according to the different combination modes of the gas and its contact objects, two modes of pumping and pumping are realized. The former can ensure that a sufficient amount of required gas is obtained, while the latter helps to achieve full contact between the gas and the air chamber.

[0020] (5) The gas path structure constructed by the present invention can be stacked, making the system smaller in size and lighter in weight, and easy to move and carry. It is a gas detection system that integrates gas collection, real-time algorithm processing and feedback of results. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a patch shell of a dual-channel T-shaped pin patch multiplexing electronic nose air chamber structure

[0022] Figure 2 It is a dual-channel T-type pin patch multiplexing electronic nose air chamber structure. Figure 1 The patch shell cooperates with the pin cover to form the air chamber

[0023] Figure 3 Schematic diagram of the overall structure of the gas path and gas chamber with "reversible process"

[0024] Figure 4 Schematic diagram of the gas path structure in gas collection mode

[0025] Figure 5 Schematic diagram of the gas path structure in the gas chamber cleaning mode

[0026] Figure 6 Schematic diagram of the gas path structure in gas path cleaning mode

[0027] The following are the descriptions of the reference numerals:

[0028] 1. Patch housing 2. Inlet 3. Outlet 4. Air wall

[0029] 5. Base plate 6. SMD gas sensor 7. SMD temperature and humidity sensor

[0030] 8. Pin-type gas sensor 9. Mounting hole 10. T-shaped baffle

[0031] 11.Fixing hole 12 pin cover DETAILED DESCRIPTION

[0032] In order to be able to quickly and accurately detect the type of environmental gas, it is far from enough to rely solely on the recognition algorithm. It is also necessary to ensure that the inside of the trachea will not be affected by the interference of gas superposition caused by multiple acquisitions. The current gas acquisition and identification device (electronic nose) to be tested mainly adopts a dual-path air intake structure, relying on a three-way solenoid valve to complete the gas path switching. The main problem is that the front-end sampling tube cannot be cleaned during the cleaning process, resulting in interference between the two injections or a long wait before the next injection. In response to the shortcomings of the above gas path structure, the present invention 1) designs a dual-path T-shaped pin patch multiplexing gas chamber structure, which can make the gas to be measured fully contact with the sensor and improve the reaction efficiency of the two, which is of great significance for the rapid and accurate detection of the electronic nose; 2) inspired by the design of the differential circuit structure, a single air pump air path structure composed of a two-way and a three-way solenoid valve is proposed. Compared with the traditional structure, the air path structure designed by the present invention only needs to control the air pump to evacuate in one direction, and can "clean" every component of the air path system, thereby ensuring the effectiveness, stability and reliability of the gas sensor data acquisition.

[0033] In real-world applications, the device is held close to the point being collected, and the front-end external air tube is placed near the object being measured for collection. The electronic nose air path and air chamber design method of the present invention involves: the design of a new air chamber, the design of gas collection and its cleaning link. The following is a detailed description:

[0034] (1) Dual-channel T-type pin patch multiplexing air chamber design

[0035] The dual-channel T-shaped patch reusable gas chamber of the present invention comprises a patch housing 1 and a pin cover 12, which are mated and connected to form the gas chamber. The patch housing 1 comprises a base plate 5 and a gas wall 4. An inlet 2 and an outlet 3 are provided at each end of the gas wall 4, and the inner surface of the base plate 5 is provided with locations for arranging a patch gas sensor array. The pin cover 12 is provided with an array of mounting holes for securing the pin gas sensor array. A T-shaped baffle 10 is provided between the bottom edge 5 and the middle of the pin cover 12, with the cross section of the T-shaped baffle 10 adjacent to the gas outlet 3. Fixing holes 11 are provided at corresponding positions on the patch housing 1 and the pin cover 12, allowing them to be bolted together to form the gas chamber.

[0036] The design ideas are as follows:

[0037] a) T-type structure design: In real-world scenarios, changes in wind direction and speed may affect the diffusion and mixing of gases, significantly increasing the difficulty of electronic nose detection. Based on the structure of the mammalian nasal cavity and the statistics and analysis of previous experimental data, a dual-path T-type pin patch multiplexing air chamber structure is proposed, such as Figure 1 and Figure 2As shown in the figure, the air chamber structure resembles that of a nasal cavity, narrow in front and wide in the back. It incorporates a T-shaped structure similar to the nasal concha. This narrow-front-wide-back design, along with structural obstruction and dispersion, reduces airflow velocity in the sensor area, promoting turbulence at the sensor. This in turn ensures full contact between the gas and the sensor, improving reaction efficiency and enhancing detection efficiency and accuracy.

[0038] b) Pin patch multiplexing structure design: The air chamber design is closely related to the type and number of sensors. Too many gas sensors will significantly increase the volume of the air chamber and reduce the portability of the electronic nose system. On the contrary, too few sensors may result in insufficient gas information being collected and unable to effectively identify it. To this end, the present invention proposes a pin patch multiplexing air chamber structure, that is, the pin type sensor is Figure 2 , patch sensors in Figure 1 , reuse the same gas chamber, so that a large number of sensors can be collected without increasing the volume of the gas chamber.

[0039] c) The pin sensor is placed outside the air chamber: Considering that the pin sensor is larger in size and thus has a higher position in the air chamber Figure 2 This invention intends to expose only the sensing surface (the part that contacts and reacts with the gas) in the air chamber cavity, and place the rest of the part outside the air chamber cavity. On this basis, it is intended to set the distance between the top of the air chamber and the bottom to no more than 5mm to compress the volume of the air chamber cavity.

[0040] (2) New “reversible process” gas path structure design

[0041] Since the collected gas often accumulates or remains in the air chamber and trachea of ​​the electronic nose device, it needs to be cleaned after the collection is completed. The present invention provides a new gas path design scheme, the overall design is as follows Figure 3 As shown in the figure, the air circuit structure consists of three normally closed three-way solenoid valves, one normally closed two-way solenoid valve, two three-way connectors, an air pump, an air chamber, and several nylon air tubes. The three-way solenoid valve has three air ports. According to the control principle of the three-way solenoid valve, air ports 1 and 2 of the normally closed three-way solenoid valve are connected, and air ports 1 and 3 are connected after receiving a control signal. The normally closed two-way solenoid valve is cut off and connected after receiving a control signal.

[0042] a) Gas collection mode: The gas pump is placed between the gas to be measured and the gas chamber. For the gas to be measured, the pump is used to extract the gas, and for the gas chamber, the pump is used to blow the gas into the gas chamber to ensure that the gas is in full contact with the sensor array in the gas chamber. The working gas path in the collection mode is as follows Figure 4As shown, the controller selects the operating mode and sends a control signal. The gas to be tested enters the lower left inlet. In this mode, the three-way solenoid valve No. 1 is controlled to open ports 1 and 2 and close port 3; the three-way solenoid valve No. 2 is controlled to open ports 1 and 3 and close port 2; and the three-way solenoid valve No. 3 is controlled to open ports 1 and 2 and close port 3. Since the two-way solenoid valves are normally closed, they are not controlled and remain in their original state. The air pump's operating time is controlled by PWM, delivering the gas to be tested into the air chamber, where it contacts the sensor, and finally exits the device through the air pipe of the lower right outlet port 1.

[0043] b) Air chamber cleaning mode: The air pump is located between the air chamber and outlet 2, and uses a pumping method to draw clean air into the air chamber to achieve air chamber cleaning. Figure 5 As shown, the controller selects the operating mode and sends a control signal, allowing clean air to enter through outlet 1 in the lower right "reverse process." In this mode, three-way solenoid valve No. 3 must be controlled to have ports 1 and 2 open and port 3 closed; three-way solenoid valve No. 1 must have ports 1 and 2 open and port 3 closed; and three-way solenoid valve No. 2 must have ports 1 and 2 open and port 3 closed. PWM controls the air pump's operating time to ensure that clean air fully flows through the air chamber, achieving the desired cleaning effect. Air then exits the device through outlet 2 in the upper left corner. In actual operation, compared to the acquisition mode, the open and closed states of three-way solenoid valves No. 1 and 3 remain unchanged, so only the state of three-way solenoid valve No. 2 needs to be controlled.

[0044] c) Gas path cleaning mode: The air pump is placed between the gas outlet 1 and the sample inlet, and uses the pumping method to continuously suck in sufficient clean air to clean the remaining pipes with residual gas to be tested. Figure 6 As shown, the controller selects the operating mode and sends a control signal, allowing clean air to enter through outlet 1 in the "reverse process" on the lower right. In this mode, the three-way solenoid valve No. 3 must be controlled to have ports 1 and 3 open and port 2 closed; the normally closed two-way solenoid valve must be open; the three-way solenoid valve No. 1 must have ports 1 and 3 open and port 2 closed; and the three-way solenoid valve No. 2 must have ports 1 and 3 open and port 2 closed. PWM control of the air pump's operating time ensures that clean air fully flows through the nylon air tubing, achieving the purpose of cleaning the air path. Air then exits the device through the inlet air tubing in the "reverse process" on the lower left. In actual operation, compared to the chamber cleaning mode, the states of all three-way solenoid valves change, and the normally closed two-way solenoid valve is also open, requiring control of the actual states of all four solenoid valves.

[0045] After the air chamber and air path cleaning modes are completed, all air paths and air chambers, including the inlet and outlet pipes, are fully exposed to clean air for the collected gas, completing the cleaning process. Furthermore, in actual operation, after the air chamber cleaning process is completed, it is necessary to control and change the state of the normally closed two-way solenoid valve and the three-way solenoid valves No. 1 and No. 3 to facilitate the next collection and identification task.

[0046] In summary, the beneficial effects of this patent application mainly relate to the following aspects:

[0047] (1) Designed a new electronic nose chamber,

[0048] S1. A bionic nasal concha dual-path T-shaped pin patch multiplexed air chamber structure is proposed to obtain as much sample information as possible while maintaining a small volume.

[0049] (2) A new gas path structure was proposed.

[0050] S2. The gas path structure has three working modes: gas collection, gas chamber cleaning, and gas path cleaning. It can completely clean all the forward gas paths involved in the collection, which can significantly improve the cleaning effect and thus improve the gas identification performance;

[0051] S3. To address the problem that the front-end sampling tube of the traditional gas path is difficult to clean, the structure designed in the present invention can achieve the "reverse process" of the collection process in the gas tube cleaning mode, thereby effectively cleaning the front-end sampling tube;

[0052] S4. According to the air circuit structure described in the above claims, the air circuit system only requires a single air pump, and the air pump only needs one-way air intake in the three modes to complete all the above functions.

[0053] S5. According to the gas circuit structure described in the above claims, the gas collection, gas chamber cleaning and gas circuit cleaning time can be independently regulated by switching the solenoid valve gas circuit and controlling the working time of the air pump.

[0054] Those skilled in the art will appreciate that the specific structures and processes described in the above detailed embodiments are merely illustrative and non-limiting. Furthermore, those skilled in the art may combine the various technical features described above in various possible ways to create new technical solutions or make other modifications, all of which fall within the scope of the present invention.

Claims

1. An electronic nose with a dual-path T-shaped pin patch multiplexing gas chamber and a reversible process gas path, characterized in that: The dual-channel T-shaped pin patch multiplexed gas chamber includes a patch housing and a pin cover that are connected to form an air chamber. The patch housing includes a bottom plate and a gas wall. An inlet and an outlet are provided at both ends of the gas wall. A position for arranging a patch gas sensor array is provided on the inner surface of the bottom plate. The pin cover is provided with an array of mounting holes for fixing the pin gas sensor array. A T-shaped baffle is provided at the bottom edge and the middle of the pin cover, with the horizontal plate of the T-shaped baffle close to the outlet. The reversible process gas circuit includes an inlet, a first gas outlet, a second gas outlet, three normally closed three-way solenoid valves, a normally closed two-way solenoid valve, two three-way connectors, and an air pump. The two three-way connectors are respectively referred to as the first and second three-way connectors. According to the control rule of the three-way solenoid valve, the first gas port and the second gas port of the normally closed three-way solenoid valve are connected. After receiving the control signal, the first gas port and the third gas port are connected. The three normally closed three-way solenoid valves are respectively referred to as the first, second, and third three-way solenoid valves. The normally closed two-way solenoid valve is cut off and is connected after receiving the control signal. The air pump is connected between the second air port of the first three-way solenoid valve and the first air port of the second three-way solenoid valve, and the second air port of the second three-way solenoid valve is connected to the second gas outlet; Both ends of the normally closed two-way solenoid valve are connected to one port of the first and second three-way connectors respectively; The other two ports of the second three-way connector are connected, one to the third air port of the second three-way solenoid valve, and the other to the inlet of the air chamber; The injection port and the first gas port of the first three-way solenoid valve are respectively connected to the other two ports of the first three-way connector; The gas chamber outlet is connected to the second gas port of the third three-way solenoid valve and the first gas port of the third three-way solenoid valve. The first gas port of the third three-way solenoid valve is the first gas outlet. The third gas port of the third three-way solenoid valve is connected to the third gas port of the first three-way solenoid valve.

2. The electronic nose according to claim 1, wherein: When the electronic nose operates in gas collection mode, the air pump is located between the sampling port and the gas chamber. For the gas to be tested, a pumping method is adopted, and for the gas chamber, a pump blowing method is adopted to send the gas into the gas chamber, so as to ensure that the gas is in full contact with the sensor array in the gas chamber; the working mode is selected by the controller, and a control signal is sent. The gas to be tested enters from the sampling port, and the first and second gas ports of the first three-way solenoid valve are controlled to be connected, and the third gas port is blocked; the first and third gas ports of the second three-way solenoid valve are connected, and the second gas port is blocked; the first and second gas ports of the third three-way solenoid valve are connected, and the third gas port is blocked; the two-way solenoid valve is normally closed and is not controlled, and maintains its original state; the air pump working time is controlled by PWM, and the gas to be tested is sent into the gas chamber to contact the sensor, and the gas is discharged through the first gas outlet pipe.

3. The electronic nose according to claim 1, wherein: When the electronic nose operates in the air chamber cleaning mode, the air pump is located between the air chamber and the second gas outlet, and clean air is sucked into the air chamber by pumping to achieve the purpose of cleaning the air chamber. The controller selects the working mode and sends a control signal. Clean air enters from the first gas outlet of the "reverse process", controlling the first and second gas ports of the third three-way solenoid valve to be connected and the third gas port to be blocked; the first and second gas ports of the first three-way solenoid valve are connected and the third gas port is blocked; the first and second gas ports of the second three-way solenoid valve are connected and the third gas port is blocked. The air pump operating time is controlled by PWM to ensure that clean air fully flows through the air chamber to achieve the purpose of cleaning the air chamber, and the air is discharged from the second gas outlet.

4. The electronic nose according to claim 1, wherein: When the electronic nose operates in the gas path cleaning mode, the air pump is located between the first gas outlet and the sample inlet, and uses a pumping method to continuously inhale sufficient clean air to clean the remaining pipes with residual gas to be tested. The controller selects the working mode and sends a control signal. Clean air enters from the first gas outlet of the "reverse process" to control the first and third gas ports of the third three-way solenoid valve to be connected and the second gas port to be blocked; the normally closed two-way solenoid valve is turned on; the first and third gas ports of the first three-way solenoid valve are connected and the second gas port is blocked; the first and third gas ports of the second three-way solenoid valve are connected and the second gas port is blocked; the air pump working time is controlled by PWM to ensure that clean air fully flows through the air pipe to achieve the purpose of cleaning the gas path, and the air is discharged from the sample inlet air pipe of the "reverse process".

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