Gas sampling structure of electronic nose

Abstract

The utility model provides a gas sampling structure of an electronic nose. The gas sampling structure comprises a gas chamber, a circuit board, a sensor, a gas suction pump and a connector, the bottom of the air chamber is opened and is detachably provided with a circuit board; the front surface of the circuit board faces downwards and is used for connecting a circuit; an air inlet is formed in the top of the air chamber, a horizontally-arranged baffle is connected to the position under the air inlet through a connecting column, and a space is reserved between the baffle and the air inlet to form an air channel; a plurality of sensors are arranged on the back face of the circuit board, the sensors are arranged in an array and symmetrically distributed, and an air outlet is further formed in the circuit board. The air outlet is connected with the air suction pump through a pipeline, the air suction pump is further connected with the connector through a pipeline, and the connector is fixed to the electronic nose air chamber and used for leading out test air. The baffle plate arranged in the sampling structure plays a role in uniformly dispersing gas, so that the gas can be fully contacted with the sensor, the wire connection is simpler, and perforation is not needed.

Description

Technical Field

[0001] The utility model relates to the technical field of gas detection, in particular to a gas sampling structure of an electronic nose. Background Art

[0002] An electronic nose records the reactions of chemical substances present in an odor by using a series of sensors, and then classifies the reactions through advanced signal processing techniques. Compared with other gas detection methods, the electronic nose has the advantages of no need for pretreatment of the sample to be measured, rapid analysis, simplicity, etc., and is considered a novel "green" bionic detection technology. At present, electronic noses are being applied in industrial food monitoring, source identification, explosive detection, flammable liquid identification, disease detection / diagnosis, olfactory loss or hyposmia assistance, ambient air monitoring, and environmental impact monitoring, etc.

[0003] The gas sampling structure is a closed structure in the electronic nose used to collect gases and make full contact with sensors. There are some problems in the existing gas sampling structure designs. For example, in CN216747523U, this design requires a dedicated interface for the cleaning hose, a fan module needs to be set inside the air chamber to make the gas evenly distributed, and the design does not clarify the positional and directional relationship between the internal sensor array circuit module and each gas interface, so the gas flow direction relative to the sensor cannot be determined; it does not clarify how the electrical connection between the sensor array circuit module and the microcontroller passes through the air chamber. If the sensor circuit module directly passes through the air chamber through a connecting wire, additional sealing treatment is required, and the connecting wire makes the internal structure more complex, restricting the further reduction of the volume. For example, in CN108490114A, in this design, according to the gas flow direction, there is a certain sequence for the gas sensors to contact the gas. The sensor that contacts the gas first has a certain adsorption effect on the gas to be measured, which will affect the response of the sensor that contacts the gas later (the contact between each sensor and the gas is uneven), and there is a certain interference for the use scenarios with low gas concentration; and the gas molecules impact the gas sensor from the side, while the air inlet of the sensor is on the upper part of the sensor, and for the use scenarios with low gas concentration, the contact between the sensor and the gas molecules is not sufficient; this design requires the sensor to be a patch-type sensor with a relatively low height, which has certain limitations. If a through-hole sensor with a relatively high height is used, since the gas comes from the side of the sensor, the sensor that contacts the gas first will block the gas flow, resulting in an impact on the sensor that contacts the gas later. In "Multi-information Fusion Recognition Technology for Meat Freshness Based on Bionic Electronic Nose", the sensors are circularly distributed along the periphery of the air chamber, resulting in overly complex circuit connections of the sensors, and the sensors cannot be integrated through a planar circuit board; and according to the gas flow direction, the gas molecules impact the gas sensor from the side, while the air inlet of the sensor is on the upper part of the sensor, and for the use scenarios with low gas concentration, the contact between the sensor and the gas molecules is not sufficient. For example, in CN114137163A, the front part of the air chamber is in an open state with a relatively large opening. When the gas to be measured is inhaled, a gas flow with a determined path cannot be formed, and the gas uniformity cannot be guaranteed; and the large opening of the air chamber will also lead to poor sealing with the outside world, and external gases are likely to enter the air chamber, and the gas inhaled into the air chamber is likely to escape, resulting in unstable gas concentration in the air chamber; the gas to be measured may also bypass the sensor and directly enter the air outlet, and the contact with the sensor is not sufficient; in addition, this design does not clarify how the electrical connection between the sensor group and the microcontroller passes through the air chamber. If the sensor circuit module directly passes through the air chamber through a connecting wire, additional sealing treatment is required, and the connecting wire makes the internal structure more complex, restricting the further reduction of the volume. Content of the Utility Model

[0004] The present utility model aims to solve at least one of the technical problems in the related technologies to some extent. For this reason, the present utility model proposes a gas sampling structure for an electronic nose.

[0005] A gas sampling structure of an electronic nose, comprising: a gas chamber, a circuit board, sensors, an air suction pump and a connector; the bottom of the gas chamber is open and detachably installs the circuit board, and the front side of the circuit board faces downward for connecting circuits; an air inlet is provided at the top of the gas chamber, and a horizontally arranged baffle is connected below the air inlet through a connecting column, and a space is left between the baffle and the air inlet to form a gas passage; several sensors are provided on the back of the circuit board, the sensors are arranged in an array and symmetrically distributed, and an air outlet is also provided on the circuit board; the air outlet is connected to the air suction pump through a pipeline, and the air suction pump is also connected to the connector through a pipeline, and the connector is fixed on the gas chamber of the electronic nose, and the connector is used to export the test gas.

[0006] Further, a fixing sleeve is fixedly provided on the inner side wall of the gas chamber, the circuit board is provided with a through hole facing the fixing sleeve, and a screw passes through the through hole and is screwed with the fixing sleeve.

[0007] Further, several fixing sleeves are provided and evenly distributed.

[0008] Further, an annular groove is provided at the bottom edge of the gas chamber, and a sealing gasket is provided in the groove.

[0009] Further, an air inlet connector is provided at the air inlet, and the air inlet connector is a taper head.

[0010] Further, an air outlet connector is provided at the air outlet, and the air outlet connector is a taper head; the air outlet connector is inserted at the air outlet and fixed at the air outlet through a nut, and the height of the air outlet connector inserted into the gas chamber is lower than the height of the sensors.

[0011] Further, the connector includes an inner connector, a retaining piece and a chuck; the chuck is fixed at the end of the inner connector, the chuck is disc-shaped, and a cut surface is provided at the edge of the disc, the outer diameter of the chuck is larger than the outer diameter of the inner connector, a baffle is provided on the outer side wall of the inner connector, a gap is left between the retaining piece and the chuck, the chuck is embedded in the housing of the electronic nose and flush with the outer side wall of the housing of the electronic nose, and the retaining piece abuts against the inner side wall of the housing of the electronic nose.

[0012] Further, the connector further includes an outer connector, and the outer connector is fixedly connected to the chuck.

[0013] Further, there are more than 2 connecting columns, and a gap is left between adjacent two connecting columns to facilitate gas flow.

[0014] Advantages and beneficial effects of the present utility model:

[0015] (1) A baffle is provided directly below the air inlet of the air chamber. When gas enters the air chamber, it encounters the baffle, disperses evenly in all directions through the gaps between the connecting columns, and flows downward along the air chamber, making direct and sufficient contact with the air inlet holes at the upper part of the sensor, and then flows out through the air outlet joint. The height of the air outlet joint inside the air chamber is lower than the height of the sensor, thus ensuring that the gas passes through the sensor first and then flows out through the air outlet joint, so as to ensure sufficient contact between the gas and the sensor.

[0016] (2) There is no need to specifically set a cleaning port, and the sensor can be cleaned directly by inhaling clean gas into the air chamber.

[0017] (3) After passing through the baffle, the gas can naturally be evenly distributed inside the air chamber without the need to set a fan for stirring.

[0018] (4) The gas can form a definite flow direction, and the flow direction of gas molecules directly points to the air inlet holes at the top of the gas sensor, enabling sufficient contact with the sensor.

[0019] (5) Except for the open air inlet and air outlet, other parts of the air chamber itself have good sealing performance, and there will be no situation where external gas enters the air chamber or the gas inhaled into the air chamber escapes, resulting in unstable gas concentration inside the air chamber.

[0020] (6) The gas sensors are symmetrically distributed, and there is no sequence in contacting the gas, and there are no problems of mutual interference and occlusion.

[0021] (7) The gas sensor is integrated with a planar circuit board, and the circuit design is simple and easy to implement. The electrical signal of the sensor can be directly led out from the front of the circuit board, and the wire connection is simpler, without the need for perforation and sealing treatment at the wire outlet, further reducing the complexity and shrinking the volume of the air chamber. Description of the Drawings

[0022] The above-mentioned and / or additional aspects and advantages of the present utility model will become obvious and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0023] Figure 1 is a schematic structural diagram of the gas sampling structure of the electronic nose;

[0024] Figure 2 is the internal structural diagram of the air chamber;

[0025] Figure 3 is the schematic diagram of the gas flow direction in the air chamber;

[0026] Figure 4 is the installation structural diagram of the gas sampling structure of the electronic nose;

[0027] Figure 5 is the installation structural diagram of the connector;

[0028] Figure 6 is another structural diagram of the connector;

[0029] Figure 7 is an arrangement of the sensors;

[0030] Figure 8 is another arrangement of the sensors.

[0031] Reference numerals:

[0032] 1. Gas chamber; 2. Intake port; 3. Exhaust port; 4. Circuit board; 5. Baffle; 6. Connecting column; 7. Sensor; 8. Fixed sleeve; 9. Screw; 10. Annular groove; 11. Sealing gasket; 12. Suction pump; 13. Connector; 14. Inner connector; 15. Flap; 16. Chuck; 17. Outer connector; 18. Exhaust connector; 19. Nut; 20. Wire. Detailed implementation manners

[0033] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

[0035] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0036] In the present utility model, unless otherwise clearly defined and limited, terms such as "installation", "connection", "linkage", "fixation", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral body; it may be a mechanical connection, an electrical connection, or communication with each other; it may be a direct connection, or an indirect connection through an intermediate medium, and may be the internal communication between two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0037] In the present utility model, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0038] In the present utility model, terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0039] As Figures 1-5 shown, a gas sampling structure of an electronic nose includes: a gas chamber 1, a circuit board 4, sensors 7, an air suction pump 12, and a connector 13; the bottom of the gas chamber 1 is open and the circuit board 4 is detachably installed, and the front side of the circuit board 4 faces downward for connecting circuits; an air inlet 2 is provided at the top of the gas chamber 1, and a horizontally arranged baffle 5 is connected below the air inlet 2 through a connecting column 6, and a space is left between the baffle 5 and the air inlet 2 to form a gas passage; a plurality of sensors 7 are provided on the back of the circuit board 4, the sensors 7 are arranged in an array and symmetrically distributed, and an air outlet 3 is also provided on the circuit board 4; the air outlet 3 is connected to the air suction pump 12 through a pipeline, the air suction pump 12 is also connected to the connector 13 through a pipeline, the connector 13 is fixed on the gas chamber 1 of the electronic nose, and the connector 13 is used to export the test gas.

[0040] Among them, the shape of the gas chamber can be any symmetric shape, such as square, rectangle, circle, ellipse, pentagon, hexagon, etc. The number of gas sensors can be increased as long as the distribution of the gas sensors matches the shape of the gas chamber to form a symmetric distribution. For example, Figure 7 and Figure 8 as shown, the sensors can be set according to the shape of the gas chamber. Figure 7 For a rectangular gas chamber, 4 sensors can be set, Figure 8 and for a hexagonal gas chamber, 6 sensors can be set.

[0041] The sensor can be a patch-type sensor with a lower height or a through-hole type sensor with a higher height.

[0042] Except for the screw holes and the gas outlet, there are no other through-holes inside the gas chamber on the soldered circuit board to ensure airtightness.

[0043] A baffle is provided directly below the air inlet. When the gas enters the gas chamber and encounters the baffle, it disperses evenly in all directions through the gaps between the connecting columns and flows downward along the gas chamber, directly and fully contacting the air inlet holes on the upper part of the sensor, and then flowing out through the gas outlet. The position of the gas outlet is lower than the height of the sensor, so as to ensure that the gas first passes through the sensor and then flows out through the gas outlet, thus ensuring full contact between the gas and the sensor. In addition, the electrical signal of the sensor can be directly led out from the front of the circuit board, and the connection of the wire 20 is simpler without the need for perforation.

[0044] Exemplarily, a fixing sleeve 8 is fixedly provided on the inner side wall of the gas chamber 1. The circuit board 4 is provided with a through-hole opposite to the fixing sleeve 8, and a screw 9 passes through the through-hole and is screwed with the fixing sleeve 8. The connection method is simple, facilitating installation and disassembly.

[0045] Specifically, several fixing sleeves 8 are provided and evenly distributed, and the number of fixing sleeves can be determined according to the shape of the gas chamber.

[0046] Specifically, as can be Figure 2 shown in the figure, there are 4, two in a group, symmetrically arranged on the front and rear inner side walls of the gas chamber 1.

[0047] Exemplarily, an annular groove 10 is provided at the bottom edge of the gas chamber 1, and a sealing gasket 11 is provided in the groove. The sealing gasket plays a sealing role to prevent air leakage from causing inaccurate testing.

[0048] Exemplarily, an air inlet joint is provided at the air inlet 2, and the air inlet joint is a tapered head.

[0049] The gas chamber can collect gas from a relatively far place through the tapered head connecting the pipeline, or the tapered head can be removed, and it is just a straight gas inlet.

[0050] Exemplarily, an air outlet joint is provided at the air outlet 3, and the air outlet joint is a tapered head; the air outlet joint is inserted into the air outlet and fixed at the air outlet by a nut, and the height of the air outlet joint inserted into the air chamber is lower than the height of the sensor. Thus, the gas first passes through the sensor and then flows out through the air outlet joint, ensuring sufficient contact between the gas and the sensor.

[0051] Exemplarily, as Figure 5 shown, the connector 13 includes an inner connector 14, a retaining piece 15 and a chuck 16; the chuck 16 is fixed at the end of the inner connector 14. The chuck 16 is disc-shaped, and a cut surface is provided at the edge of the disc, which can prevent the chuck from rotating. The outer diameter of the chuck 16 is larger than the outer diameter of the inner connector 14. A baffle is provided on the outer side wall of the inner connector 14, and a gap is left between the retaining piece 15 and the chuck 16. The chuck 16 is embedded in the electronic nose housing and flush with the outer side wall of the electronic nose housing, and the retaining piece 15 abuts against the inner side wall of the electronic nose housing.

[0052] The air outlet is connected to an air suction pump, and the air suction pump is connected to the connector, so as to extract and discharge the detected gas.

[0053] Specifically, as Figure 6 shown, the connector 13 may also include an outer connector 17, and the outer connector 17 is fixedly connected to the chuck 16.

[0054] The outer connector can be connected to a gas container such as an air bag to recover the gas. Moreover, the container can also contain the gas to be measured. The container is simultaneously connected to the air inlet, so that the gas in the container enters the air chamber from the air inlet and is recovered to the container from the air outlet after testing.

[0055] Exemplarily, there are more than 2 connecting columns 6, and a gap is left between adjacent two connecting columns 6 to facilitate gas flow.

[0056] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A gas sampling structure of an electronic nose, characterized in that, Comprising: An air chamber, a circuit board, sensors, a suction pump, and a connector; the bottom of the air chamber is open and the circuit board is detachably installed, and the front side of the circuit board faces downwards for connecting circuits; an air inlet is provided at the top of the air chamber, and a horizontally arranged baffle is connected below the air inlet through a connecting column, and a space is left between the baffle and the air inlet to form a gas passage; several sensors are provided on the back side of the circuit board, the sensors are arranged in an array and symmetrically distributed, and an air outlet is also provided on the circuit board; the air outlet is connected to the suction pump through a pipeline, the suction pump is also connected to the connector through a pipeline, the connector is fixed on the electronic nose air chamber, and the connector is used to export the test gas.

2. The gas sampling structure of the electronic nose according to claim 1, characterized in that, A fixed sleeve is fixedly provided on the inner side wall of the air chamber, and a through hole is provided on the circuit board opposite to the fixed sleeve, and a screw passes through the through hole and is screwed with the fixed sleeve.

3. The gas sampling structure of the electronic nose according to claim 2, characterized in that, There are several fixed sleeves and they are evenly distributed.

4. The gas sampling structure of the electronic nose according to claim 1, characterized in that, An annular groove is provided at the bottom edge of the air chamber, and a sealing gasket is provided in the groove.

5. The gas sampling structure of the electronic nose according to claim 1, characterized in that An air inlet connector is provided at the air inlet, and the air inlet connector is a taper head.

6. The gas sampling structure of the electronic nose according to claim 1, characterized in that, An air outlet connector is provided at the air outlet, and the air outlet connector is a taper head; the air outlet connector is inserted at the air outlet and fixed at the air outlet through a nut, and the height of the air outlet connector inserted into the air chamber is lower than the height of the sensors.

7. The gas sampling structure of the electronic nose according to claim 1, characterized in that, The connector includes an inner connector, a retaining piece, and a chuck; the chuck is fixed at the end of the inner connector, the chuck is disc-shaped, and a cut surface is provided at the edge of the disc, the outer diameter of the chuck is larger than the outer diameter of the inner connector, a baffle is provided on the outer side wall of the inner connector, a gap is left between the retaining piece and the chuck, the chuck is embedded in the electronic nose housing and is flush with the outer side wall of the electronic nose housing, and the retaining piece abuts against the inner side wall of the electronic nose housing.

8. The gas sampling structure of the electronic nose according to claim 7, characterized in that, The connector further includes an outer connector, and the outer connector is fixedly connected to the chuck.

9. The gas sampling structure of the electronic nose according to claim 1, characterized in that There are more than 2 connecting columns, and a gap is left between adjacent two connecting columns to facilitate gas flow.

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