Electronic nose with double-path T-shaped pin patch multiplexing air chamber and reversible process air path

Abstract

The invention discloses an electronic nose with a double-path T-shaped pin patch multiplexing air chamber and a reversible process air path, the double-path T-shaped pin patch multiplexing air chamber comprises a patch shell and a pin cover body which are mutually matched and connected to form the air chamber, the patch shell comprises a bottom plate and an air wall, an inlet and an outlet are formed in the two ends of the air wall, and the reversible process air path is arranged in the patch shell. The inner surface of the bottom plate is provided with a position for arranging the patch type gas sensor array; the pin cover body is provided with a mounting hole array for fixing the pin type gas sensor array; a T-shaped baffle is arranged at the bottom edge and the middle part of the pin cover body; and a transverse 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 the technical field related to the gas path and gas chamber structure design of a gas detection device. Background Art

[0002] Gas / odor is an important property of matter and is often used as an important indicator to determine a certain type of compound. In the food industry, odor can be used to detect the food production process to ensure the freshness of raw materials and the safety of food; in environmental monitoring, water quality can be analyzed through changes in gas to understand the degree of water pollution, and the type of gas in a dangerous environment can be determined, which helps reduce the occurrence of disasters. Today, more and more scenarios require the use of gas detection and identification technology.

[0003] Common gas detection methods can be mainly divided into chemical analysis, instrumental analysis and sensor technology. Among them, chemical analysis can be divided into absorption and combustion, and instrumental analysis can be divided into spectral analysis and chromatographic analysis. The electronic nose is an instrument composed of a variety of sensors, which can detect the types of gases in the environment by embedding appropriate algorithms. Among them, the gas path and gas chamber system are important components of the electronic nose, mainly composed of solenoid valves, air pumps, air pipes and air chambers. The gas path channel composed of solenoid valves, air pumps and air pipes controls the flow of gas in the electronic nose. The opening and closing of the solenoid valve can effectively switch the gas path, thereby realizing the gas collection and cleaning functions of the gas path and air chamber; the gas path and gas chamber jointly determine the contact mode, degree and effect of the gas and the sensor array, which can directly affect the gas identification performance. Summary of the invention

[0004] Since the gas to be tested in actual situations is often not of a single type, the purpose of the present invention is to provide a new type of electronic nose gas path and gas chamber structure, which can reduce or eliminate the influence of gas residue in the gas path on the accuracy and stability of the recognition result while the gas to be tested is in full contact with the sensor. The technical solution of the present invention is as follows:

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

[0006] Further, the reversible process gas circuit includes an inlet, a gas circuit outlet 1, a gas circuit outlet 2, three normally closed three-way solenoid valves, a normally closed two-way solenoid valve, two three-way connectors, and an air pump, and the two three-way connectors are respectively called 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 called 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 the 3rd port 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 air chamber. For the gas to be tested, a pumping method is adopted, and for the air chamber, a pump blowing method is adopted to send the gas into the air chamber, so as to ensure that the gas is in full contact with the sensor array in the air chamber; the working mode is selected by the controller, and a control signal is sent, and the gas to be tested enters from the sampling port, and the first three-way solenoid valve 1 and 2 are controlled to be connected, and the 3rd port is blocked; the second three-way solenoid valve 1 and 3 are connected, and the 2nd port is blocked; the third three-way solenoid valve 1 and 2 are connected, and the 3rd port is blocked; the two-way solenoid valve is a normally closed type, which is not controlled and maintains the original state; the working time of the air pump is controlled by PWM, and the gas to be tested is sent into the air chamber to contact with the sensor, and discharged from the air outlet 1 air pipe.

[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, so as to achieve the cleaning of the air chamber. The working mode is selected by the controller, and the 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 are controlled to be turned on, and the port 3 is turned off; the first three-way solenoid valve 1 and 2 are turned on, and the port 3 is turned off; the second three-way solenoid valve 1 and 2 are turned on, and the port 3 is turned off. The working time of the air pump is controlled by PWM, so that the 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 a sufficient amount of clean air is continuously sucked in by pumping to clean the remaining pipes with residual gas to be tested. The working mode is selected by the controller, and the 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 turned on, and the 2 port to be cut off; the normally closed two-way solenoid valve is turned on; the first three-way solenoid valve 1 and 3 gas ports are turned on, and the 2 port is cut off; the second three-way solenoid valve 1 and 3 gas ports are turned on, and the 2 port is cut off; the air pump working time is controlled by PWM, so that the clean air can 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 the present invention are: 1) by designing a new type of bionic air chamber, turbulent airflow is generated at the sensor array to improve the contact reaction quality between the gas to be tested and the gas sensor array; 2) rapid cleaning of each section of the gas path is achieved; 3) in different cleaning modes, unidirectional air extraction is always maintained with only a single air pump to reduce the size of the equipment and the high cost caused by multiple air pumps; 4) the air chamber and the air inlet pipe are cleaned separately during the cleaning process to ensure high-quality cleaning effects. The beneficial effects of the present 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) In view of the problem that the front-end sample inlet tube of the traditional gas path is not involved in the cleaning, the structure designed by the present invention can realize the "reverse process" of the collection process in the gas pipe cleaning mode, thereby effectively cleaning the front-end gas pipe. At the same time, after the gas pipe cleaning is completed, the collection task can be continued by simply resetting the solenoid valve.

[0018] (3) A three-mode gas path structure is proposed, which can switch different gas paths according to needs, and has multiple functions such as gas collection, gas chamber cleaning and air pipe cleaning. In addition, due to the different types of materials of the gas chamber and the air pipe, the cleaning time required for the two is inconsistent, and there is cross-contamination between the residual gases. To address this problem, the present invention implements the gas chamber cleaning and the air pipe cleaning separately, which reduces the mutual 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 realizing the control algorithm. Meanwhile, according to different combination modes of the gas and its contact object, two modes, namely pumping and pumping, are realized. The former can ensure that a sufficient amount of the required gas is obtained, while the latter helps to realize sufficient contact between the gas and the air chamber.

[0020] (5) The gas path structure constructed by the present invention can be stacked, so that the system is small in size and light in weight, and is 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-pin patch multiplexing electronic nose air chamber structure

[0022] Figure 2 It is a dual-channel T-pin patch multiplexed electronic nose air chamber structure. Figure 1 The patch housing cooperates with the pin cover body of the air chamber

[0023] Figure 3 Schematic diagram of the overall structure of the gas path and gas chamber that can be "reversed"

[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 shell 2. Inlet 3. Outlet 4. Air wall

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

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

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

[0032] In order to detect the category of environmental gases quickly and accurately, 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 gas superposition interference caused by multiple acquisitions. The current gas collection 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 the interference between the two injections before and after or a long wait before the next injection. In view of the shortcomings of the above gas path structure, the present invention 1) designs a dual-path T-type pin patch multiplexing gas chamber structure, which can make the gas to be tested fully contact with the sensor and improve the reaction efficiency of both, 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" each component of the air path system, thereby ensuring the effectiveness, stability and reliability of gas sensor data acquisition.

[0033] In real-world applications, hold the device close to the point to be collected, and place the front-end external air tube near the object to be 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 pin patch multiplexed gas chamber of the present invention comprises a patch housing 1 and a pin cover 12 which are connected to form a gas chamber after being matched with each other. The patch housing 1 comprises a bottom plate 5 and a gas wall 4. An inlet 2 and an outlet 3 are arranged at both ends of the gas wall 4. Positions for arranging a patch gas sensor array are arranged on the inner surface of the bottom plate 5. The pin cover 12 is provided with an array of mounting holes for fixing the pin gas sensor array. A T-shaped baffle 10 is arranged in the middle of the bottom edge 5 and the pin cover 12, and the horizontal plate of the T-shaped baffle 10 is close to the gas outlet 3. Fixing holes 11 are arranged at corresponding positions of the patch housing 1 and the pin cover 12, which are used to connect the two into a gas chamber by bolts.

[0036] The design ideas are as follows:

[0037] a) T-type structure design: In real-life scenarios, changes in wind direction and wind speed may affect the diffusion and mixing of gases, greatly increasing the difficulty of electronic nose detection. Based on the reference to the nasal structure of mammals and the statistics and analysis of previous experimental data, a dual-channel 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 is similar to the nasal structure, which is narrow in front and wide in the back. A T-shaped structure similar to the nasal concha is set inside the air chamber. The narrow front and wide back design as well as the structural blocking and dispersion can reduce the speed of the airflow in the sensor area, which is conducive to generating turbulence at the sensor, thereby allowing the gas to fully contact the sensor to improve the reaction efficiency. Improve 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 , reusing the same gas chamber, so that a considerable number of sensors can be gathered 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 its sensing surface (the part that contacts and reacts with the gas) in the air chamber cavity, and the rest is placed 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 gas 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 pipes, wherein the three-way solenoid valve contains three air ports. According to the control rule of the three-way solenoid valve, the air ports 1 and 2 of the normally closed three-way solenoid valve are connected, and the air ports 1 and 3 are connected after receiving the control signal. The normally closed two-way solenoid valve is cut off and connected after receiving the control signal.

[0042] a) Gas collection mode: The gas pump is placed between the gas to be tested and the gas chamber. For the gas to be tested, 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 working mode and sends the control signal. The gas to be tested enters from the lower left inlet. In this mode, it is necessary to control the No. 1 three-way solenoid valve to have ports 1 and 2 connected and port 3 closed; the No. 2 three-way solenoid valve to have ports 1 and 3 connected and port 2 closed; the No. 3 three-way solenoid valve to have ports 1 and 2 connected and port 3 closed; because the two-way solenoid valve is a normally closed type, it is not controlled and remains in its original state. The working time of the air pump is controlled by PWM, and the gas to be tested is sent into the air chamber to contact the sensor, and finally discharged from 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 the outlet 2, and the clean air is sucked into the air chamber by pumping, so as to clean the air chamber. Figure 5 As shown, the controller selects the working mode and sends the control signal. Clean air enters from the outlet 1 of the "reverse process" on the lower right. In this mode, it is necessary to control the No. 3 three-way solenoid valve to be turned on at the 1st and 2nd ports and turned off at the 3rd port; the No. 1 three-way solenoid valve to be turned on at the 1st and 2nd ports and turned off at the 3rd port; the No. 2 three-way solenoid valve to be turned on at the 1st and 2nd ports and turned off at the 3rd port. 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. The air is discharged from the upper left outlet 2. In actual operation, compared with the acquisition mode, the opening state of the No. 1 and No. 3 three-way solenoid valves has not changed, so it is only necessary to control the change of the state of the No. 2 three-way solenoid valve.

[0044] c) 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. Figure 6 As shown, the controller selects the working mode and sends the control signal. Clean air enters from the outlet 1 of the "reverse process" on the lower right. In this mode, it is necessary to control the No. 3 three-way solenoid valve to be turned on at ports 1 and 3 and to be turned off at port 2; the normally closed two-way solenoid valve is turned on; the No. 1 three-way solenoid valve is turned on at ports 1 and 3 and to be turned off at port 2; the No. 2 three-way solenoid valve is turned on at ports 1 and 3 and to be turned off at port 2. The air pump working time is controlled by PWM so that clean air can fully flow through the nylon air pipe to achieve the purpose of cleaning the air path. The air is discharged from the inlet air pipe of the "reverse process" on the lower left. In actual operation, compared with the cleaning air chamber mode, the states of all three-way solenoid valves are changed, and the normally closed two-way solenoid valve is turned on, so it is necessary to control the actual states of the four solenoid valves.

[0045] After the two modes of cleaning the air chamber and the air path are completed, all the air paths and air chambers, including the air inlet and outlet pipes, are fully exposed to clean air for the collected gas and are cleaned. At the same time, in the 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 1st and 3rd three-way solenoid valves to facilitate the next collection and identification task.

[0046] In summary, the beneficial effects of this patent application mainly involve 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 is 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. Aiming at the problem that the front-end sampling tube of the traditional gas path is difficult to clean, the structure designed by the present invention can realize the "reverse process" of the collection process in the gas tube cleaning mode, thereby effectively cleaning the front-end sampling gas tube;

[0052] S4. According to the air circuit structure described in the above claims, the air circuit system only needs 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, air 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 should understand that the specific structures and processes shown in the above specific embodiments are only exemplary and not restrictive. Moreover, those skilled in the art can combine the various technical features shown above in various possible ways to form new technical solutions, or make other changes, which are all within the scope of the present invention.

Claims

1. An electronic nose having a dual-channel T-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 shell and a pin cover body 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, and a position for arranging a patch gas sensor array is provided on the inner surface of the bottom plate; the pin cover body 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 body, and the cross plate of the T-shaped baffle is close to the outlet.

2. The electronic nose according to claim 1, characterized in that: The reversible process gas circuit includes an inlet, a gas circuit outlet 1, a gas circuit outlet 2, three normally closed three-way solenoid valves, a normally closed two-way solenoid valve, two three-way connectors, and an air pump, and the two three-way connectors are respectively called 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, and the three normally closed three-way solenoid valves are respectively called 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, 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; 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, one is connected to the 3rd port of the second three-way solenoid valve, and the other is connected to the inlet of the air chamber; 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; 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.

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

4. The electronic nose according to claim 2, characterized in that: 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 the 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 are controlled to be turned on, and the 3rd port is turned off; the first three-way solenoid valve 1 and 2 are turned on, and the 3rd port is turned off; the second three-way solenoid valve 1 and 2 are turned on, and the 3rd port is turned off. The working time of the air pump is controlled by PWM, so that the 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.

5. The electronic nose according to claim 2, characterized in that: 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 a sufficient amount of clean air is continuously sucked in by pumping to clean the remaining pipes with residual gas to be tested. The working mode is selected by the controller, and the 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 the 2 port 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 turned on, and the 2 port is closed; the second three-way solenoid valve 1 and 3 gas ports are turned on, and the 2 port is closed; the air pump working time is controlled by PWM to make the clean air 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".

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