Four-side type electronic nose gas induction chamber with flow field correction function

Abstract

The invention discloses a four-side type electronic nose gas sensing chamber with a flow field correction function, which comprises a gas outlet, a gas sensing chamber and a gas inlet, four corners of the gas outlet and the gas inlet are respectively fixed on the gas sensing chamber through screws I, and the four corners of the gas outlet are respectively provided with screw and nut fixing holes I; the four corners of the two ends of the gas sensing chamber are each provided with a second screw and nut fixing hole, first embedded nuts are arranged in the second screw and nut fixing holes, the four corners of the gas inlet are each provided with a third screw and nut fixing hole, the first screws are divided into two sets, the number of each set of first screws is four, and the number of each set of first screws is four. One set of first screws penetrate through the first screw and nut fixing holes correspondingly and are screwed into the second screw and nut fixing holes to be connected with the first embedded nuts, and the other set of first screws penetrate through the third screw and nut fixing holes correspondingly. According to the invention, the gas distribution in the gas induction chamber can be conveniently corrected.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic nose gas sensing chambers, and particularly to a four-sided electronic nose gas sensing chamber with a flow field correction function. Background Art

[0002] As a device for gas detection and identification, the electronic nose has been widely used in various fields. In the field of food detection, the electronic nose device can be used as a food quality evaluation device to quickly classify food grades; in the field of public safety, existing electronic nose devices have been used for fire investigations, bringing great convenience to work such as accident cause analysis and accident liability assessment. Similarly, the electronic nose has certain applications in fields such as medical diagnosis, environmental quality evaluation, petrochemical safety, agriculture, and military. The gas chamber of the electronic nose, as a key module inside the electronic nose, plays a crucial role in the working process of the electronic nose. Therefore, the design of the gas chamber structure for the sensor array is particularly important.

[0003] Research institutions at home and abroad have proposed some sensor chamber design schemes for electronic nose systems. "Electronic nose sensing chamber design for confined space atmospheric monitoring" published by Bakar et al. from the University of Perth, Malaysia, in the International Conference on Mathematics, Engineering and Industrial Applications 2016 (ICoMEIA2016) conducted various different designs on the electronic nose chamber and gave corresponding fluid simulations, verifying that the chamber design scheme for a specific sensor array can greatly improve the response effect of the sensor. However, the proposed chamber design scheme still does not have strong versatility and cannot be applied in batches to the design of various types of sensor chambers. The paper "A radially symmetric measurement chamber for electronic noses" published by Francesco et al. from the Institute of Clinical Physiology of the National Research Council of Italy in Sensor and Actuators B: Chemical gave a design of a new type of radially symmetric electronic nose measurement chamber and innovatively carried out reforms. Their design is different from the previous design method of placing several gas sensors in a single measurement chamber. Instead, the measurement chamber is transformed into a slender narrow channel to facilitate the flow of gas in the airway. At the same time, the position and number of gas sensors are arranged according to the designed symmetric radial airway. This design method greatly ensures the consistency of the sensors and also provides great convenience for replacing gas sensors and cleaning the chamber. However, this design has a high complexity and there is also a problem that the chamber volume is too large when the number of sensors is large, and it cannot be applied to the design of large-scale sensor chambers.

[0004] The existing sensor chamber designs of electronic nose systems have the following deficiencies:

[0005] (1) The uniformity of the internal flow field of the chamber is poor. Affected by the structure of the sensor array, the flow field distribution in the chamber is usually not uniform enough, resulting in poor response consistency of multiple sensors in the same chamber and bringing difficulties to the subsequent gas recognition work;

[0006] (2) The transferability of the chamber design scheme needs to be improved. The existing chambers can often only be applied to a certain type of sensor array. When using a new type of sensor or a new sensor array layout, the gas flow field inside the chamber will change unpredictably. Therefore, the chamber structure needs to be redesigned, reducing the efficiency of product development;

[0007] (3) The air chamber has limited accommodation capacity. When the number of sensors increases significantly, problems such as insufficient power of the air pump and uneven flow field will occur due to the overly large volume of the air chamber.

[0008] There are few air chamber design solutions that can correct the unevenness of the internal flow field of the air chamber, and the existing solutions have problems such as poor uniformity, low mobility, and limited accommodation capacity, and cannot be directly applied to other types of electronic nose systems. In view of the deficiencies in the existing air chamber design solutions of electronic noses, the present invention proposes a four-sided electronic nose gas sensing chamber with a flow field correction function. The proposed device has the function of correcting the unevenness and instability of the internal flow field of the electronic nose air chamber, and at the same time, this device can be directly applied to the air chamber design solutions of various electronic nose systems. Summary of the Invention

[0009] The purpose of the present invention is to provide a four-sided electronic nose gas sensing chamber with a flow field correction function, including a gas outlet, a gas sensing chamber, and a gas inlet. The four corners of the gas outlet and the gas inlet are respectively fixed to the gas sensing chamber by screws 1. Screw nut fixing holes 1 are respectively opened at the four corners of the gas outlet. Screw nut fixing holes 2 are respectively opened at the four corners at both ends of the gas sensing chamber. Inner nuts 1 are arranged inside the screw nut fixing holes 2. Screw nut fixing holes 3 are respectively opened at the four corners of the gas inlet. The screws 1 are divided into two groups, and the number of screws 1 in each group is four. One group of screws 1 respectively penetrate through the screw nut fixing holes 1 and are screwed into the screw nut fixing holes 2 to be connected with the inner nut 1. The other group of screws 1 respectively penetrate through the screw nut fixing holes 3 and are screwed into the screw nut fixing holes 2 to be connected with the inner nut. The four sides of the gas sensing chamber are respectively connected to four PCB boards by screws 2, and a sensor array is respectively welded on each PCB board.

[0010] Preferably, an air pipe connection port is opened at the central position of the gas outlet. A sealing ring hook groove is arranged inside the gas outlet, and a sealing ring 1 is arranged inside the sealing ring hook groove.

[0011] Preferably, gas sensing chamber connection holes are respectively opened at the four corners of the PCB board. The screws 2 penetrate through the gas sensing chamber connection holes and are screwed into the PCB board fixing holes opened on the gas sensing chamber to be connected with the inner nut 2.

[0012] Preferably, the shape of the gas sensing chamber is a tetrahedron.

[0013] Preferably, a cavity is formed inside the gas induction chamber. Gas inlet and outlet mounting holes are respectively arranged at both ends of the gas induction chamber. Gas sensor array mounting holes are respectively formed on four surfaces of the gas induction chamber. Gas sensor sealing ring grooves are respectively arranged at the outer edges of the gas sensor array mounting holes on each surface, and a second sealing ring is arranged inside the gas sensor sealing ring grooves.

[0014] Preferably, an air inlet is formed at the central position of the gas inlet, and a gas filtering structure is arranged inside the gas inlet.

[0015] Preferably, the gas filtering structure is of a Dalton plate type distributed radially.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. The gas filtering structure of the present invention is a Dalton plate type structure distributed radially. This structure can filter and sort the gas flowing into the electronic nose gas chamber, thereby effectively improving the uniformity of the gas flow in the electronic nose gas chamber. At the same time, the distribution of the sensor array and the gas flow field inside the gas chamber is symmetrical, so that the contact degree between each sensor and the gas is basically the same, improving the consistency of the sensor response.

[0018] 2. The gas outlet and gas inlet of the present invention are designed separately from the gas induction chamber. The sizes of the gas inlet and gas outlet and the detailed size of the gas filtering structure can be modified according to requirements, making the design of the gas induction chamber structure more suitable for the actual working conditions. Moreover, the inside of the gas induction chamber is a simple channel-shaped structure, which is convenient for the flow of gas and the cleaning of the gas induction chamber, and is also convenient for the interaction between gas and sensors.

[0019] 3. The gas induction chamber of the present invention is a tetrahedral structure, and a sensor array is arranged on each surface. This structure can effectively increase the number of gas sensors that can be accommodated in the gas chamber of the same volume, greatly improving the utilization efficiency of the internal space of the gas chamber. It is applicable to the design of the gas chamber structure of a large sensor array and can be modified on the basis of the current gas induction chamber. When the number of sensors increases, the radial length of the gas chamber can be simply extended, so that there are more sensor holes to accommodate more gas sensors, without having to re-design and perform simulation analysis, greatly saving the time cost of designing the gas chamber and standardizing the design process of the gas chamber structure.

[0020] 4. The overall size of the gas induction chamber of the present invention is small, which is convenient for the installation and cooperation of other components of the electronic nose system, improving the integration degree of the design. At the same time, for a large number of gas sensors, the gas flow field volume inside the gas induction chamber is small, so a gas pump with a smaller power can be used to save costs. Description of the Drawings

[0021] Figure 1 is the schematic diagram of the external structure of the present invention Figure 1 ;

[0022] Figure 2 is the schematic diagram of the external structure of the present invention Figure 2 ;

[0023] Figure 3 is the schematic diagram of the external structure of the present invention Figure 3 ;

[0024] Figure 4 is the sectional view of the present invention;

[0025] Figure 5 is the schematic diagram of the external structure of the gas outlet of the present invention;

[0026] Figure 6 is the schematic diagram of the internal structure of the gas outlet of the present invention;

[0027] Figure 7 is the sectional view of the gas outlet of the present invention;

[0028] Figure 8 is the schematic diagram of the structure of the gas induction chamber of the present invention Figure 1 ;

[0029] Figure 9 is the schematic diagram of the structure of the gas induction chamber of the present invention Figure 2 ;

[0030] Figure 10 is the schematic diagram of the internal structure of the gas induction chamber of the present invention;

[0031] Figure 11 is the schematic diagram of the connection structure between the PCB board and the sensor array of the present invention;

[0032] Figure 12 is the schematic diagram of the structure of the gas inlet of the present invention;

[0033] Figure 13 is the sectional view of the gas inlet of the present invention;

[0034] Figure 14 is the simulation result diagram of the internal flow field distribution of the gas chamber without installing the "Dalton plate" type device;

[0035] Figure 15 is for Figure 14 Under the same gas chamber structure and inlet and outlet conditions, it is the internal flow field distribution diagram of the gas chamber after installing the gas filtering structure.

[0036] The reference numerals and names in the figure are as follows:

[0037] 1. Gas outlet; 101. Pipe connection port; 102. First screw and nut fixing hole; 103. Sealing ring hook groove; 2. PCB board; 201. Gas induction chamber connection hole; 3. Gas induction chamber; 301. Cavity; 302. Gas inlet and outlet installation hole; 303. Second screw and nut fixing hole; 304. Gas sensor sealing ring groove; 305. Gas sensor array installation hole; 306. PCB board fixing hole; 4. Sensor array; 5. Gas inlet; 501. Air filter structure; 502. Air inlet; 503. Third screw and nut fixing hole; 6. First embedded nut; 7. Second embedded nut; 8. First screw. Detailed implementation manners

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] As shown in the Figure 1-13 accompanying drawings, a four-sided electronic nose gas induction chamber with a flow field correction function provided by the present invention includes a gas outlet 1, a gas induction chamber 3, and a gas inlet 5. The four corners of the gas outlet 1 and the gas inlet 5 are respectively fixed on the gas induction chamber 3 by the first screws 8. The four corners of the gas outlet 1 are respectively provided with the first screw and nut fixing holes 102. The four corners at both ends of the gas induction chamber 3 are respectively provided with the second screw and nut fixing holes 303. The first embedded nuts 6 are arranged inside the second screw and nut fixing holes 303. The four corners of the gas inlet 5 are respectively provided with the third screw and nut fixing holes 503. The first screws 8 are divided into two groups, and the number of the first screws 8 in each group is four. One group of the first screws 8 respectively penetrate through the first screw and nut fixing holes 102 and are screwed into the second screw and nut fixing holes 303 to be connected with the first embedded nuts 6. The other group of the first screws 8 respectively penetrate through the third screw and nut fixing holes 503 and are screwed into the second screw and nut fixing holes 303 to be connected with the embedded nut 6. The four sides of the gas induction chamber 3 are respectively connected to the four PCB boards 2 by the second screws, and the sensor arrays 4 are respectively welded on each PCB board 2.

[0040] Specifically, both the gas outlet 1 and the gas inlet 5 are made of photosensitive resin material by 3D printing, and the main body is funnel-shaped.

[0041] Specifically, a pipe connection port 101 is opened at the central position of the gas outlet 1, and a sealing ring hook groove 103 is arranged inside the gas outlet 1. A first sealing ring is arranged inside the sealing ring hook groove 103. The arrangement of the first sealing ring can achieve sealing and prevent gas leakage.

[0042] Specifically, gas induction chamber connection holes 201 are respectively formed at four corners of the PCB board 2. The second screw passes through the gas induction chamber connection holes 201 and is screwed into the inner part of the PCB board fixing holes 306 formed on the gas induction chamber 3 to be connected with the second embedded nut 7.

[0043] Specifically, the gas induction chamber 3 is in a tetrahedral shape.

[0044] Specifically, as shown in the appendix Figure 6-8 As shown in the figure, a cavity 301 is formed inside the gas induction chamber 3. Gas inlet and outlet mounting holes 302 are respectively arranged at two ends of the gas induction chamber 3. Gas sensor array mounting holes 305 are respectively formed on four surfaces of the gas induction chamber 3. Gas sensor seal grooves 304 are respectively arranged at the outer edges of the gas sensor array mounting holes 305 on each surface. A second seal ring is arranged inside the gas sensor seal grooves 304. The arrangement of the second seal ring can achieve sealing and prevent gas leakage.

[0045] Specifically, an air inlet 502 is formed at the central position of the gas inlet 5, and a gas filtering structure 501 is arranged inside the gas inlet 5.

[0046] Specifically, the gas filtering structure 501 is in a radially distributed Dalton plate type. The diameter of each internal column and the distance between adjacent columns can be adjusted according to requirements to achieve the best gas combing effect.

[0047] Working principle: During use, a set of first screws 8 respectively pass through the first screw nut fixing holes 102 and are screwed into the second screw nut fixing holes 303 to be connected with the first embedded nut 6, so as to realize the connection between the air inlet and outlet 1 and the air inlet 5. Then, the sensor array 4 is inserted into the gas sensor array mounting holes 305. Another set of first screws 8 respectively pass through the third screw nut fixing holes 503 and are screwed into the second screw nut fixing holes 303 to be connected with the embedded nut 6, so as to realize the installation of the PCB board 2. After installation, the gas is sent into the cavity 301 through the air inlet 502 on the air inlet 5, enters the cavity 301 after passing through the gas filtering structure 501, and contacts the sensor array 4. Since the gas filtering structure 501 is in a radially distributed Dalton plate type structure, this structure can filter and comb the gas flowing into the electronic nose gas chamber, thereby effectively improving the uniformity of the gas flow in the electronic nose gas chamber. At the same time, the distribution of the sensor array and the gas flow field inside the gas chamber is symmetrical, so that the contact degree between each sensor and the gas is basically consistent, improving the consistency of the sensor response. Finally, the gas is sent out through the gas outlet 1 to realize gas detection.

[0048] The correction effect of the gas filtering structure 501 on the internal flow field of the gas induction chamber 3 is as shown in the appendix Figure 14, as shown in Figure 15, where the blue area indicates that the gas flow rate in this area is slower, and the cyan area indicates that the gas flow rate in this area is faster. Inside the electronic nose chamber, the area with a slower flow rate represents the air originally present inside the gas sensing chamber 3, while the area with a faster flow rate represents the gas to be measured entering the chamber. From the simulation results, it can be seen that the flow field distribution inside the chamber is more uniform than before, which is conducive to the mutual contact between the gas sensor and the gas to be measured, and can effectively improve the consistency of the output signal of the gas sensor.

[0049] Using the technical solution of the present invention, or those skilled in the art designing similar technical solutions inspired by the technical solution of the present invention and achieving the above technical effects, all fall within the protection scope of the present invention.

Claims

1. A four-sided electronic nose gas sensing chamber with a flow field correction function, comprising a gas outlet (1), a gas sensing chamber (3), and a gas inlet (5), characterized in that: The four corners of the gas outlet (1) and the gas inlet (5) are fixed to the gas sensing chamber (3) by screws (8), respectively. The four corners of the gas outlet (1) are provided with screw and nut fixing holes (102), and the four corners of both ends of the gas sensing chamber (3) are provided with screw and nut fixing holes (303). The screw and nut fixing holes (303) are provided with embedded nuts (6) inside. The four corners of the gas inlet (5) are provided with screw and nut fixing holes (503), respectively. The screws (8) are divided into two groups, and each group of screws has a screw nut (6). The number of the screws (8) is four, one group of the screws (8) respectively penetrates the screw nut fixing hole (102) and is screwed into the screw nut fixing hole (303) to be connected with the embedded nut (6), and another group of the screws (8) respectively penetrates the screw nut fixing hole (503) and is screwed into the screw nut fixing hole (303) to be connected with the embedded nut (6). The four sides of the gas sensing chamber (3) are connected to the four PCB boards (2) respectively by screws (2), and each of the PCB boards (2) is respectively welded with a sensor array (4).

2. A four-sided electronic nose gas sensing chamber with flow field correction function according to claim 1, characterized in that: A gas pipe connection port (101) is provided at the center of the gas outlet (1), a sealing ring hook groove (103) is provided inside the gas outlet (1), and a sealing ring 1 is provided inside the sealing ring hook groove (103).

3. The four-sided electronic nose gas sensing chamber with flow field correction function according to claim 1, characterized in that: Gas sensing chamber connection holes (201) are respectively provided at the four corners of the PCB board (2), and the second screw passes through the gas sensing chamber connection hole (201) and is screwed into the interior of the PCB board fixing hole (306) provided on the gas sensing chamber (3) to be connected with the second embedded nut (7).

4. The four-sided electronic nose gas sensing chamber with flow field correction function according to claim 1, characterized in that: The gas sensing chamber (3) is in the shape of a tetrahedron.

5. The four-sided electronic nose gas sensing chamber with flow field correction function according to claim 1, characterized in that: The gas sensing chamber (3) has a cavity (301) formed inside, gas inlet and outlet mounting holes (302) are respectively formed at two ends of the gas sensing chamber (3), gas sensor array mounting holes (305) are respectively formed on four sides of the gas sensing chamber (3), gas sensor sealing ring grooves (304) are respectively formed at the outer edges of the gas sensor array mounting holes (305) on each side, and a second sealing ring is formed inside the gas sensor sealing ring grooves (304).

6. The four-sided electronic nose gas sensing chamber with flow field correction function according to claim 1, characterized in that: An air inlet (502) is provided at the center of the gas inlet (5), and an air filtering structure (501) is provided inside the gas inlet (5).

7. The four-sided electronic nose gas sensing chamber with flow field correction function according to claim 1, characterized in that: The air filtering structure (501) is a radially distributed Dalton plate type.

Images