Integrated multi-sensor electronic nose system

Abstract

The invention relates to the technical field of gas detection, and discloses an integrated multi-sensor electronic nose system which comprises a gas inlet unit, a reaction unit and a gas exhaust unit, the gas inlet unit comprises a first two-position three-way valve, a second two-position three-way valve and a third two-position three-way valve, the first two-position three-way valve is connected with the base line adjusting channel, the sampling channel and the second two-position three-way valve, and the third two-position three-way valve is connected with the enrichment channel and the second two-position three-way valve; the second two-position three-way valve and the third two-position three-way valve are connected with the reaction unit; the reaction unit comprises a first reaction chamber, a second reaction chamber and a third reaction chamber which are arranged in parallel, and an outlet of the reaction unit is connected with the exhaust unit; the exhaust unit comprises a fourth two-position three-way valve, and the fourth two-position three-way valve is connected with the first exhaust port and the second exhaust port. By integrating various sensors and reaction chambers, the accuracy and reliability of gas detection are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection, and in particular to an integrated multi-sensor electronic nose system. Background Art

[0002] In the field of gas detection technology, traditional electronic nose systems usually rely on a single type of sensor to detect and analyze gas components. However, due to the different response characteristics of different gas components to sensors, a single sensor is often difficult to accurately distinguish and identify complex gas mixtures, reducing the accuracy and reliability of detection. In order to overcome these limitations, the present invention proposes an integrated multi-sensor electronic nose system. The system improves the accuracy and reliability of gas detection by integrating multiple different types of sensors. Summary of the invention

[0003] The purpose of the present invention is to provide an integrated multi-sensor electronic nose system to solve the above problems.

[0004] The present invention provides an integrated multi-sensor electronic nose system, comprising: an air intake unit, a reaction unit and an exhaust unit;

[0005] The air intake unit comprises a first two-position three-way valve, a second two-position three-way valve and a third two-position three-way valve, wherein the port A of the first two-position three-way valve is connected to the baseline adjustment channel, the port B of the first two-position three-way valve is connected to the sampling channel, the port C of the first two-position three-way valve is connected to the port B of the second two-position three-way valve, the port A of the third two-position three-way valve is connected to the enrichment channel, the port C of the third two-position three-way valve is connected to the port C of the second two-position three-way valve, the port A of the second two-position three-way valve is connected to the reaction unit, and the port B of the third two-position three-way valve is connected to the reaction unit;

[0006] The reaction unit comprises a first reaction chamber, a second reaction chamber and a third reaction chamber, wherein the first reaction chamber, the second reaction chamber and the third reaction chamber are arranged in parallel, and outlets of the first reaction chamber, the second reaction chamber and the third reaction chamber are all connected to the exhaust unit;

[0007] The exhaust unit comprises a fourth two-position three-way valve, wherein the C port of the fourth two-position three-way valve is connected to the outlet of the reaction unit, the B port of the fourth two-position three-way valve is connected to the first exhaust port, and the A port of the fourth two-position three-way valve is connected to the second exhaust port.

[0008] Preferably, the air intake unit further comprises a first vacuum pump and an electronic flow meter;

[0009] The inlet of the first vacuum pump is connected to the A port of the second two-position three-way valve, the inlet of the first vacuum pump is connected to the B port of the third two-position three-way valve, the outlet of the first vacuum pump is connected to the electronic flowmeter, and the electronic flowmeter is connected to the reaction unit.

[0010] Preferably, the reaction unit comprises a first two-position two-way valve, a second two-position two-way valve, a third two-position two-way valve and a fourth two-position two-way valve;

[0011] The inlet of the first two-position two-way valve is connected to the electronic flow meter, and the outlet of the first two-position two-way valve is connected to the inlets of the first reaction chamber, the second reaction chamber and the third reaction chamber;

[0012] The inlet of the second two-position two-way valve is connected to the outlet of the first reaction chamber, and the outlet of the second two-position two-way valve is connected to the exhaust unit;

[0013] The inlet of the third two-position two-way valve is connected to the outlet of the second reaction chamber, and the outlet of the third two-position two-way valve is connected to the exhaust unit;

[0014] The inlet of the fourth two-position two-way valve is connected to the outlet of the third reaction chamber, and the outlet of the fourth two-position two-way valve is connected to the exhaust unit.

[0015] Preferably, the exhaust unit further comprises a second vacuum pump and a manual flow meter;

[0016] The inlet of the second vacuum pump is connected to the outlet of the reaction unit, the outlet of the second vacuum pump is connected to the manual flow meter, and the outlet of the manual flow meter is connected to the C port of the fourth two-position three-way valve.

[0017] Preferably, the first two-position three-way valve, the second two-position three-way valve, the third two-position three-way valve and the fourth two-position three-way valve are all solenoid valves, and the AC port is connected when the first two-position three-way valve, the second two-position three-way valve, the third two-position three-way valve and the fourth two-position three-way valve are powered off, and the BC port is connected when the first two-position three-way valve, the second two-position three-way valve, the third two-position three-way valve and the fourth two-position three-way valve are powered on.

[0018] Preferably, the first reaction chamber is provided with:

[0019] An oxygen sensor, used for detecting the oxygen concentration in the first reaction chamber;

[0020] The carbon dioxide sensor is used to detect the carbon dioxide concentration in the first reaction chamber.

[0021] Preferably, the second reaction chamber is provided with:

[0022] A methane sensor, used for detecting the methane concentration in the second reaction chamber;

[0023] Propane and butane sensors, used to detect the concentration of propane and butane in the second reaction chamber;

[0024] A hydrogen sensor, used for detecting the hydrogen concentration in the second reaction chamber;

[0025] A carbon monoxide sensor, used for detecting the concentration of carbon monoxide in the second reaction chamber;

[0026] The composite sensor is used to detect the concentration of alkane gas in the second reaction chamber.

[0027] Preferably, a plurality of PID sensors are arranged in the third reaction chamber, and the PID sensors are used to detect ethanol, amines, hydrogen sulfide, aldehydes, lipids and ketone compounds.

[0028] Preferably, the electronic nose system includes a baseline adjustment mode, a sampling mode and an enrichment mode;

[0029] The baseline adjustment mode is: adjusting the electronic flowmeter to the initial value, connecting the baseline adjustment channel to the standard gas, energizing the second two-position three-way valve, the third two-position three-way valve, and the first two-position two-way valve, energizing the first vacuum pump to draw the standard gas through the electronic flowmeter into the first reaction chamber, the second reaction chamber, and the third reaction chamber; at the same time, energizing the second two-position two-way valve, the third two-position two-way valve, and the fourth two-position two-way valve, energizing the second vacuum pump to draw the mixed gas of the standard gas and air in the reaction unit and discharge it through the second exhaust port until the sensor values ​​in the first reaction chamber, the second reaction chamber, and the third reaction chamber are stable.

[0030] Preferably, the sampling mode is: after the baseline adjustment mode is completed, the second two-position three-way valve, the third two-position three-way valve, the first two-position two-way valve and the first vacuum pump are powered off; the second vacuum pump is powered on to extract the standard gas in the reaction unit;

[0031] The first two-position three-way valve, the second two-position three-way valve, the third two-position three-way valve and the first two-position two-way valve are energized, the first vacuum pump is energized to draw the sampling gas into the first reaction chamber, the second reaction chamber and the third reaction chamber, the second two-position two-way valve, the third two-position two-way valve, the fourth two-position two-way valve and the fourth two-position three-way valve are energized, the second vacuum pump is energized to draw the mixed gas of the standard gas and the sampling gas in the reaction unit and discharge it through the first exhaust port until the sensor values ​​in the first reaction chamber, the second reaction chamber and the third reaction chamber are stable.

[0032] Compared with the prior art, the invention has the beneficial effect that it can detect multiple gas components at the same time by integrating multiple different types of sensors, and comprehensively analyze the detection results through data fusion technology, thereby improving the accuracy and reliability of gas detection. In addition, the system also has a self-calibration function, can adapt to environmental changes, and ensure long-term stable operation.

[0033] The present invention sets different reaction chambers and channels, and the system can process a variety of gas samples and is suitable for different application scenarios. For example, the baseline adjustment channel can be used to calibrate the sensor, the sampling channel is used to introduce the gas to be tested, and the enrichment channel can be used to improve the detection sensitivity of low-concentration gas. The use of a two-position three-way valve increases the flexibility of the system and allows fast switching between different operating modes. For example, different intake or exhaust paths can be selected by changing the state of the valve to adapt to different experimental needs. The first, second and third reaction chambers arranged in parallel can improve the processing capacity of the system, so that multiple samples can be analyzed at the same time, thereby improving the overall analysis efficiency. The outlet of each reaction chamber is connected to the exhaust unit, and the fourth two-position three-way valve in the exhaust unit can accurately control the exhaust path, ensuring the controllability and repeatability of the gas flow, which is crucial to ensure the accuracy of the experimental results. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0035] Figure 1 It is a structural schematic diagram of an integrated multi-sensor electronic nose system of the present invention.

[0036] In the figure, 1. baseline adjustment channel; 2. sampling channel; 3. enrichment channel; 4. first two-position three-way valve; 5. second two-position three-way valve; 6. third two-position three-way valve; 7. fourth two-position three-way valve; 8. first reaction chamber; 9. second reaction chamber; 10. third reaction chamber; 11. first vacuum pump; 12. electronic flowmeter; 13. first two-position two-way valve; 14. second two-position two-way valve; 15. third two-position two-way valve; 16. fourth two-position two-way valve; 17. second vacuum pump; 18. manual flowmeter; 19. first exhaust port; 20. second exhaust port. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0038] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0039] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0040] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0041] like Figure 1 As shown, the present invention provides an integrated multi-sensor electronic nose system, comprising: an air intake unit, a reaction unit and an exhaust unit;

[0042] The air intake unit includes a first two-position three-way valve 4, a second two-position three-way valve 5 and a third two-position three-way valve 6, wherein the A port of the first two-position three-way valve 4 is connected to the baseline adjustment channel 1, the B port of the first two-position three-way valve 4 is connected to the sampling channel 2, the C port of the first two-position three-way valve 4 is connected to the B port of the second two-position three-way valve 5, the A port of the third two-position three-way valve 6 is connected to the enrichment channel 3, the C port of the third two-position three-way valve 6 is connected to the C port of the second two-position three-way valve 5, the A port of the second two-position three-way valve 5 is connected to the reaction unit, and the B port of the third two-position three-way valve 6 is connected to the reaction unit;

[0043] The reaction unit includes a first reaction chamber 8, a second reaction chamber 9 and a third reaction chamber 10, which are arranged in parallel, and the outlets of the first reaction chamber 8, the second reaction chamber 9 and the third reaction chamber 10 are all connected to the exhaust unit;

[0044] The exhaust unit comprises a fourth two-position three-way valve 7 , the C port of the fourth two-position three-way valve 7 is connected to the outlet of the reaction unit, the B port of the fourth two-position three-way valve 7 is connected to the first exhaust port 19 , and the A port of the fourth two-position three-way valve 7 is connected to the second exhaust port 20 .

[0045] In some embodiments of the present application, the air intake unit also includes a first vacuum pump 11 and an electronic flowmeter 12; the inlet of the first vacuum pump 11 is connected to the A port of the second two-position three-way valve 5, the inlet of the first vacuum pump 11 is connected to the B port of the third two-position three-way valve 6, the outlet of the first vacuum pump 11 is connected to the electronic flowmeter 12, and the electronic flowmeter 12 is connected to the reaction unit.

[0046] In this embodiment, no matter it is standard gas, sample gas or other gas to be collected, it needs to be extracted by the first vacuum pump 11 and enter the reaction chamber through the electronic flow meter 12.

[0047] The use of the electronic flow meter 12 ensures the precise control of the gas flow, which is essential for the accuracy and repeatability of the chemical reaction in the reaction unit. By accurately measuring and adjusting the gas flow, the gas can be evenly distributed in the reaction chamber, thereby improving the sensitivity and accuracy of the detection. In addition, the real-time monitoring function of the electronic flow meter 12 can also help users to promptly detect and adjust any abnormal flow in the system, ensuring the stable operation of the entire electronic nose system. In some advanced applications, the electronic flow meter 12 can also be integrated with the control system to achieve automatic flow regulation, further improving the intelligence level of the system.

[0048] In some embodiments of the present application, the reaction unit includes a first, second, two-way valve 13, a second, second, two-way valve 14, a third, two-way valve 15 and a fourth, two-way valve 16; the inlet of the first, second, two-way valve 13 is connected to the electronic flowmeter 12, and the outlet of the first, second, two-way valve 13 is connected to the inlets of the first reaction chamber 8, the second reaction chamber 9 and the third reaction chamber 10; the inlet of the second, second, two-way valve 14 is connected to the outlet of the first reaction chamber 8, and the outlet of the second, second, two-way valve 14 is connected to the exhaust unit; the inlet of the third, second, two-way valve 15 is connected to the outlet of the second reaction chamber 9, and the outlet of the third, second, two-way valve 15 is connected to the exhaust unit; the inlet of the fourth, second, two-way valve 16 is connected to the outlet of the third reaction chamber 10, and the outlet of the fourth, second, two-way valve 16 is connected to the exhaust unit.

[0049] In this embodiment, the first two-position two-way valve 13, the second two-position two-way valve 14, the third two-position two-way valve 15 and the fourth two-position two-way valve 16 are all solenoid valves, and the first two-position two-way valve 13 is a master control valve, which is arranged on the master air intake pipeline and is used to control the gas to enter the reaction chamber. The second two-position two-way valve 14, the third two-position two-way valve 15 and the fourth two-position two-way valve 16 are branch control valves, which are arranged on the branch pipeline of each reaction chamber and are used to control the gas flow of each branch pipeline.

[0050] In some embodiments of the present application, the exhaust unit also includes a second vacuum pump 17 and a manual flow meter 18; the inlet of the second vacuum pump 17 is connected to the outlet of the reaction unit, the outlet of the second vacuum pump 17 is connected to the manual flow meter 18, and the outlet of the manual flow meter 18 is connected to the C port of the fourth two-position three-way valve 7.

[0051] In this embodiment, when the sensor in the reaction chamber completes detection, the second vacuum pump 17 is started to extract the gas in the reaction chamber and discharge it through the manual flow meter 18. The speed of gas discharge can be controlled by adjusting the manual flow meter 18.

[0052] In some embodiments of the present application, the first two-position three-way valve 4, the second two-position three-way valve 5, the third two-position three-way valve 6 and the fourth two-position three-way valve 7 are all solenoid valves. When the first two-position three-way valve 4, the second two-position three-way valve 5, the third two-position three-way valve 6 and the fourth two-position three-way valve 7 lose power, the AC port is connected, and when the first two-position three-way valve 4, the second two-position three-way valve 5, the third two-position three-way valve 6 and the fourth two-position three-way valve 7 are energized, the BC port is connected.

[0053] In this embodiment, the first two-position three-way valve 4, the second two-position three-way valve 5, the third two-position three-way valve 6 and the fourth two-position three-way valve 7 all adopt the electromagnetic control principle. When these electromagnetic valves are in the de-energized state, that is, when they do not receive current, the AC port will be in the on state, allowing gas to pass through. On the contrary, when these electromagnetic valves are energized, that is, when they receive current, the BC port will be turned on, and the gas will flow through the BC port. This design enables the system to switch the flow direction of the fluid by controlling the on and off of the current, thereby achieving precise control of the fluid path.

[0054] In some embodiments of the present application, the first reaction chamber 8 is provided with: an oxygen sensor for detecting the oxygen concentration in the first reaction chamber 8; and a carbon dioxide sensor for detecting the carbon dioxide concentration in the first reaction chamber 8.

[0055] In some embodiments of the present application, the second reaction chamber 9 is provided with: a methane sensor for detecting the methane concentration in the second reaction chamber 9; a propane and butane sensor for detecting the propane and butane concentrations in the second reaction chamber 9; a hydrogen sensor for detecting the hydrogen concentration in the second reaction chamber 9; a carbon monoxide sensor for detecting the carbon monoxide concentration in the second reaction chamber 9; and a composite sensor for detecting the alkane gas concentration in the second reaction chamber 9.

[0056] In this embodiment, the sensors provided in the second reaction chamber 9 may be: sensor MQ-6, for detecting propane, butane, and liquefied gas. Sensor MQ-2, for detecting methane (CH4). Sensor MQ-8, for detecting methane, isobutane, and various alkane gases. Sensor MQ-5, for detecting alkane gases such as methane and butane. Sensor MQ-6, again emphasizes that it is used to detect liquefied gas, propane, and butane. Sensor MQ-8, supplements its ability to detect hydrogen and carbon monoxide.

[0057] In some embodiments of the present application, a plurality of PID sensors are disposed in the third reaction chamber 10 , and the PID sensors are used to detect ethanol, amines, hydrogen sulfide, aldehydes, lipids and ketone compounds.

[0058] In this embodiment, the setting of the sensor in the third reaction chamber 10 can be: PID (photoionization) sensors are usually used for the detection of organic volatile gases such as ethanol, lipids, and alcohols. MQ series semiconductor sensors, such as MQ-2 and MQ-136, are generally used for the detection of hydrogen sulfide (H2S), amine compounds, and volatile organic compounds (VOCs). MQ-136 or MQ-4 sensors are commonly used for the special detection of hydrogen sulfide (H2S). MQ-135 or MQ-136 sensors can be used for the detection of ammonia, hydrogen sulfide and other volatile organic compounds. MQ series sensors are also usually used for the supplementary detection of ammonia, hydrogen sulfide and other volatile organic compounds in the air. Electrochemical sensors are generally used for the detection of organic solvent gases such as aldehydes and ketones. Electrochemical sensors are mainly used for the detection of formaldehyde.

[0059] In some embodiments of the present application, the electronic nose system includes a baseline adjustment mode, a sampling mode, and an enrichment mode;

[0060] The baseline adjustment mode is: adjust the electronic flowmeter 12 to the initial value, connect the baseline adjustment channel 1 to the standard gas, energize the second two-position three-way valve 5, the third two-position three-way valve 6, and the first two-position two-way valve 13, and energize the first vacuum pump 11 to extract the standard gas through the electronic flowmeter 12 into the first reaction chamber 8, the second reaction chamber 9, and the third reaction chamber 10; at the same time, the second two-position two-way valve 14, the third two-position two-way valve 15, and the fourth two-position two-way valve 16 are energized, and the second vacuum pump 17 is energized to extract the mixed gas of the standard gas and air in the reaction unit and discharge it through the second exhaust port 20 until the sensor values ​​in the first reaction chamber 8, the second reaction chamber 9, and the third reaction chamber 10 are stable.

[0061] In this embodiment, when the second vacuum pump 17 exhausts the gas in the three reaction chambers, the gas slowly flows out through the second exhaust port 20 at a speed that is first fast and then slow through the manual regulating valve. In this process, the changes in the values ​​collected by the sensors of the three reaction chambers are observed. When the baseline adjustment is stable, the sensor baseline can be calibrated.

[0062] In some embodiments of the present application, the sampling mode is: after the baseline adjustment mode is completed, the second two-position three-way valve 5, the third two-position three-way valve 6, the first two-position two-way valve 13 and the first vacuum pump 11 are powered on; the second vacuum pump 17 is powered on to extract the standard gas in the reaction unit; the first two-position three-way valve 4, the second two-position three-way valve 5, the third two-position three-way valve 6 and the first two-position two-way valve 13 are powered on, the first vacuum pump 11 is powered on to extract the sampling gas into the first reaction chamber 8, the second reaction chamber 9 and the third reaction chamber 10, the second two-position two-way valve 14, the third two-position two-way valve 15, the fourth two-position two-way valve 16 and the fourth two-position three-way valve 7 are powered on, the second vacuum pump 17 is powered on to extract the mixed gas of the standard gas and the sampling gas in the reaction unit and discharge it through the first exhaust port 19 until the sensor values ​​in the first reaction chamber 8, the second reaction chamber 9 and the third reaction chamber 10 are stable.

[0063] In the present embodiment, when the second vacuum pump 17 is powered on to extract the standard gas in the reaction unit, the flow control of the manual flow meter 18 is adjusted to slowly extract the standard gas in the three reaction chambers, reduce the concentration of the standard gas in the air chamber, and reduce the air pressure for the sampled gas to enter the air chamber. After the concentration of the air chamber is reduced (the threshold value needs to be adjusted in actual experiments), the sampling channel 2 begins to take in air, and the sampled gas quickly enters the air chamber and diffuses due to the pressure difference. When the sampled gas basically fills the air chamber, the manual flow meter 18 is adjusted to overflow part of the sampled gas and the original standard gas in the air chamber. At this time, the fourth two-position three-way valve 7 is turned on, and the gas flows out from the first exhaust port 19. After the sampled gas fills the reaction chamber, all solenoid valves and pumps are powered off, and the sensor analyzes and reads stable readings of the gas. If multiple measurements are required, the above sampling process is repeated.

[0064] The enrichment mode is: the first two-position three-way valve 4 and the second two-position three-way valve 5 are powered off, the third two-position three-way valve 6 is powered on, the first vacuum pump 11 and the first two-position two-way valve 13 are powered on, the gas to be enriched enters the reaction chamber through the enrichment channel, the second two-position two-way valve 14, the third two-position two-way valve 15, and the fourth two-position two-way valve 16 are powered on, the second vacuum pump 17 is powered on to discharge the mixed gas of the gas to be enriched and other gases in the reaction chamber until the reaction chamber is filled with the gas to be enriched, and the second two-position two-way valve 14, the third two-position two-way valve 15, and the fourth two-position two-way valve 16 are closed.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An integrated multi-sensor electronic nose system, characterized in that: include: Intake unit, reaction unit and exhaust unit; The air intake unit comprises a first two-position three-way valve, a second two-position three-way valve and a third two-position three-way valve, wherein the port A of the first two-position three-way valve is connected to the baseline adjustment channel, the port B of the first two-position three-way valve is connected to the sampling channel, the port C of the first two-position three-way valve is connected to the port B of the second two-position three-way valve, the port A of the third two-position three-way valve is connected to the enrichment channel, the port C of the third two-position three-way valve is connected to the port C of the second two-position three-way valve, the port A of the second two-position three-way valve is connected to the reaction unit, and the port B of the third two-position three-way valve is connected to the reaction unit; The reaction unit comprises a first reaction chamber, a second reaction chamber and a third reaction chamber, wherein the first reaction chamber, the second reaction chamber and the third reaction chamber are arranged in parallel, and outlets of the first reaction chamber, the second reaction chamber and the third reaction chamber are all connected to the exhaust unit; The exhaust unit comprises a fourth two-position three-way valve, wherein the C port of the fourth two-position three-way valve is connected to the outlet of the reaction unit, the B port of the fourth two-position three-way valve is connected to the first exhaust port, and the A port of the fourth two-position three-way valve is connected to the second exhaust port.

2. The integrated multi-sensor electronic nose system according to claim 1, characterized in that: The air intake unit also includes a first vacuum pump and an electronic flow meter; The inlet of the first vacuum pump is connected to the A port of the second two-position three-way valve, the inlet of the first vacuum pump is connected to the B port of the third two-position three-way valve, the outlet of the first vacuum pump is connected to the electronic flowmeter, and the electronic flowmeter is connected to the reaction unit.

3. The integrated multi-sensor electronic nose system according to claim 2, characterized in that: The reaction unit comprises a first two-position two-way valve, a second two-position two-way valve, a third two-position two-way valve and a fourth two-position two-way valve; The inlet of the first two-position two-way valve is connected to the electronic flow meter, and the outlet of the first two-position two-way valve is connected to the inlets of the first reaction chamber, the second reaction chamber and the third reaction chamber; The inlet of the second two-position two-way valve is connected to the outlet of the first reaction chamber, and the outlet of the second two-position two-way valve is connected to the exhaust unit; The inlet of the third two-position two-way valve is connected to the outlet of the second reaction chamber, and the outlet of the third two-position two-way valve is connected to the exhaust unit; The inlet of the fourth two-position two-way valve is connected to the outlet of the third reaction chamber, and the outlet of the fourth two-position two-way valve is connected to the exhaust unit.

4. The integrated multi-sensor electronic nose system according to claim 1, characterized in that: The exhaust unit also includes a second vacuum pump and a manual flow meter; The inlet of the second vacuum pump is connected to the outlet of the reaction unit, the outlet of the second vacuum pump is connected to the manual flow meter, and the outlet of the manual flow meter is connected to the C port of the fourth two-position three-way valve.

5. The integrated multi-sensor electronic nose system according to claim 4, characterized in that: The first two-position three-way valve, the second two-position three-way valve, the third two-position three-way valve and the fourth two-position three-way valve are all solenoid valves. When the first two-position three-way valve, the second two-position three-way valve, the third two-position three-way valve and the fourth two-position three-way valve lose power, the AC port is connected. When the first two-position three-way valve, the second two-position three-way valve, the third two-position three-way valve and the fourth two-position three-way valve are energized, the BC port is connected.

6. The integrated multi-sensor electronic nose system according to claim 5, characterized in that: The first reaction chamber is provided with: An oxygen sensor, used for detecting the oxygen concentration in the first reaction chamber; The carbon dioxide sensor is used to detect the carbon dioxide concentration in the first reaction chamber.

7. The integrated multi-sensor electronic nose system according to claim 6, characterized in that: The second reaction chamber is provided with: A methane sensor, used for detecting the methane concentration in the second reaction chamber; Propane and butane sensors, used to detect the concentration of propane and butane in the second reaction chamber; A hydrogen sensor, used for detecting the hydrogen concentration in the second reaction chamber; A carbon monoxide sensor, used for detecting the concentration of carbon monoxide in the second reaction chamber; The composite sensor is used to detect the concentration of alkane gas in the second reaction chamber.

8. The integrated multi-sensor electronic nose system according to claim 7, characterized in that: The third reaction chamber is provided with a plurality of PID sensors, and the PID sensors are used to detect ethanol, amines, hydrogen sulfide, aldehydes, lipids and ketone compounds.

9. The integrated multi-sensor electronic nose system according to claim 8, characterized in that: The electronic nose system includes a baseline adjustment mode, a sampling mode and an enrichment mode; The baseline adjustment mode is: adjusting the electronic flowmeter to the initial value, connecting the baseline adjustment channel to the standard gas, energizing the second two-position three-way valve, the third two-position three-way valve, and the first two-position two-way valve, energizing the first vacuum pump to draw the standard gas through the electronic flowmeter into the first reaction chamber, the second reaction chamber, and the third reaction chamber; at the same time, energizing the second two-position two-way valve, the third two-position two-way valve, and the fourth two-position two-way valve, energizing the second vacuum pump to draw the mixed gas of the standard gas and air in the reaction unit and discharge it through the second exhaust port until the sensor values ​​in the first reaction chamber, the second reaction chamber, and the third reaction chamber are stable.

10. The integrated multi-sensor electronic nose system according to claim 9, characterized in that: The sampling mode is as follows: after the baseline adjustment mode is completed, the second two-position three-way valve, the third two-position three-way valve, the first two-position two-way valve and the first vacuum pump are powered off; the second vacuum pump is powered on to extract the standard gas in the reaction unit; The first two-position three-way valve, the second two-position three-way valve, the third two-position three-way valve and the first two-position two-way valve are energized, the first vacuum pump is energized to draw the sampling gas into the first reaction chamber, the second reaction chamber and the third reaction chamber, the second two-position two-way valve, the third two-position two-way valve, the fourth two-position two-way valve and the fourth two-position three-way valve are energized, the second vacuum pump is energized to draw the mixed gas of the standard gas and the sampling gas in the reaction unit and discharge it through the first exhaust port until the sensor values ​​in the first reaction chamber, the second reaction chamber and the third reaction chamber are stable.

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