Rapid quantitative sampling device and method in electronic nose air chamber

Abstract

The invention discloses a rapid quantitative sample introduction device and method in an electronic nose air chamber, VOC quantitative measurement is completed outside the electronic nose air chamber, the measured VOC is sealed in one or more sample introduction cabins, the sample introduction cabins are placed in the electronic nose air chamber, when sample introduction is needed, an opening command is sent out from the outside of the electronic nose air chamber, and when sample introduction is needed, the electronic nose air chamber is opened. The starting task of the sample introduction device is completed through the execution mechanism, so that VOC can be volatilized into the electronic nose gas chamber on the premise that the sealing performance of the electronic nose gas chamber is not damaged. The sampling device with high sealing performance is designed, and the high-precision VOC measuring device is used in cooperation, so that the precision of the VOC sampling amount is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of electronic nose technology, specifically relating to a rapid quantitative sample introduction device and method in an electronic nose air chamber. Background Technology

[0002] On the experimental platform of the electronic nose, there is a problem of inaccurate sample concentration measurement when the electronic nose senses VOC gas samples. Since VOCs are mainly in liquid form, the gas samples after their volatilization are usually stored in the saturated vapor above the sample bottle. Headspace sampling of saturated vapor is the current mainstream technology, but the concentration of VOC gas in saturated vapor is difficult to measure quantitatively.

[0003] Patent CN 217277173 U places the sample vial outside the sensor gas chamber and uses a micro-syringe with an injection needle to quantitatively extract headspace gas from the sample vial. Although the extracted headspace gas volume is quantitative, it is a mixed gas, making it impossible to measure the content of the target sample gas within it, thus failing to achieve accurate measurement of the target sample gas concentration. Patent CN 201527429 U integrates the sample cell and sensor gas chamber into a single device, separated by a sealing gasket. A sample is added to the sample cell using a feeding tube, and the sensor detects the sample odor when the sealing gasket opens, allowing for odor detection without the need for an injection needle. However, the feeding tube design results in poor sealing between the sample cell and sensor gas chamber, making it impossible to observe whether the sample has completely evaporated after addition. Furthermore, the small space of the sample cell hinders rapid evaporation. The sample begins to evaporate immediately after being added to the sample cell, making it impossible to freely control the evaporation time.

[0004] In the experimental design of electronic noses, there is a need for multiple injections of different samples. Existing injection methods typically only allow for the injection of one odor sample at a time. When different odor samples need to be injected simultaneously, the number of inlets in the sensor chamber increases accordingly, affecting the airtightness of the sensor chamber. Furthermore, when performing multiple injections, existing injection methods usually cannot automatically control the injection time interval, which consumes a significant amount of the experimenter's time in experimental designs requiring frequent injections. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a rapid quantitative sample introduction device and method within an electronic nose air chamber. The method involves quantitatively measuring VOCs outside the electronic nose air chamber and sealing these measured VOCs in one or more sample introduction compartments, which are then placed inside the electronic nose air chamber. When sample introduction is needed, an opening command is issued from outside the electronic nose air chamber, and an actuator opens the sample introduction device, allowing VOCs to evaporate into the electronic nose air chamber without compromising its airtightness. This invention ensures the accuracy of VOC sample introduction by designing a highly airtight sample introduction device and using a high-precision VOC measurement device.

[0006] The technical solution adopted by this invention to solve its technical problem is as follows: A rapid quantitative sample introduction device in an electronic nose air chamber includes a hinge, a rubber stopper, a servo motor, a servo motor arm, a sample introduction chamber cover, a stud, a support device, and a sample introduction chamber. The sample inlet chamber is mounted on a support device; The rubber stopper and sample inlet chamber cover are used to seal the sample inlet chamber; The servo motor is mounted on a support device; The servo arm has two screws. One screw fixes the servo arm to the servo motor, and the other screw is used to adjust the distance between the servo arm and the sample inlet chamber cover, thereby adjusting the tightness of the rubber stopper. The servo motor and servo arm constitute the actuator. The servo motor controls the servo arm to rotate clockwise, and the sample inlet cover opens under the elastic force of the hinge, thereby enabling VOC to be volatilized and injected. The stud is used to balance and support the height of the servo motor.

[0007] Preferably, the sample introduction device is placed inside the electronic nose air chamber; the sample introduction device interacts with the host computer via an airtight plug on the electronic nose air chamber.

[0008] Preferably, a heating device is installed at the bottom of the sample injection chamber to heat the solid or liquid VOC to a temperature above the boiling point before sample injection, so that it can evaporate into a gaseous state in advance, or to increase the temperature of the unevaporated VOC after sample injection to accelerate the evaporation process, thereby increasing the sample injection speed.

[0009] Preferably, the heating device is a heating film.

[0010] Preferably, the sample injection device is further provided with an auxiliary clamping device for ensuring that the rubber stopper fully clamps the sample injection chamber 18.

[0011] Preferably, the auxiliary pressing device is a small manual press; the press includes a force-saving spring, an adjusting stroke screw, a machine support, a rack, an anti-slip handle, and a pressing column, which can assist in pressing the sample inlet chamber with a rubber plug at the anti-slip handle, so that the servo arm presses the sample inlet chamber and prevents VOC gas from evaporating to the outside of the sample inlet chamber.

[0012] Preferably, the actuator has two sets.

[0013] Preferably, a ventilation device is installed next to the sample introduction device, which can accelerate the flow of gas around the sample introduction device, reduce the concentration of surrounding samples, thereby accelerating the volatilization rate and helping to achieve uniform diffusion of the indoor samples.

[0014] Preferably, the sampling device has multiple components, which store different volumes or masses of VOCs, or different types of VOCs, and can be turned on and injected separately when needed to achieve the generation of stepped concentrations in the gas chamber or the generation of a mixed environment.

[0015] A rapid quantitative sample injection method in an electronic nasal air chamber includes the following steps: Step 1: Use precision measuring instruments and high-precision injection needles to accurately measure the volume of liquid VOCs; Step 2: Place the liquid VOC into the sample injection chamber; Step 3: Use the auxiliary clamping device to press the rubber stopper, and then use the servo arm to press the sample inlet chamber cover; Step 4: Place the sample introduction device in the electronic nose air chamber; Step 5: If preheating is required, turn on the heating device in advance to allow the VOCs to evaporate into a gaseous state; Step 6: When sample injection is required, a control signal is sent from the host computer to the servo motor, which controls the servo motor arm to rotate and open the sample injection chamber. Step 7: If necessary, turn on the heating and ventilation devices to accelerate the evaporation and diffusion rate; Step 8: Observe through the observation window of the electronic nose air chamber. After all the liquid VOCs have turned into gaseous VOCs, start the electronic nose odor perception task.

[0016] The beneficial effects of this invention are as follows: This invention ensures the accuracy of VOC injection volume by designing a highly airtight sample introduction device and using a high-precision VOC measuring device. Furthermore, the combined use of a host computer and an actuator enables remote control of the sample introduction device's activation and injection, guaranteeing the airtightness between the sample introduction device and the electronic nose sensor chamber. By releasing the accurately measured and sealed VOC sample into the large-volume electronic nose sensor chamber, and through preheating or post-injection heating to accelerate gas flow, rapid VOC injection into the electronic nose's sensor chamber is achieved. Attached Figure Description

[0017] Figure 1 This is a schematic diagram showing the structural relationship between the sample introduction device and the electronic nose air chamber of the present invention; Figure 2 This is a top view of the sample introduction device structure of the present invention; Figure 3 This is a side view of the sample introduction device structure of the present invention; Figure 4 This is a three-dimensional schematic diagram of the sample introduction device structure of the present invention; Figure 5 This is a flowchart of the VOC gas injection process in this invention.

[0018] Reference numerals: Screw bolts-1, 2, 3, 15, 16; hinge-4; nut-5; base plate-6, 19; rubber plug-8; servo motor-9; hinge connection device-10 (fixing the hinge to the base plate via nut 1 and stud 14); hinge stud-11; servo motor arm-12; servo motor arm gear-15; sample inlet chamber cover-13; stud bolt-14; support device-17; sample inlet chamber-18; electronic nose gas chamber-20; chamber door-21; observation window-22; airtight plug-23; sample inlet device-24; gas sensor array-25; auxiliary odor diffusion and homogenization device-26; ventilation device-27. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] This invention primarily addresses the issue of accurate and rapid VOC injection into the sensor chamber of an electronic nose, as well as the simultaneous injection of multiple odors and the need for multiple injections. The sensor chamber of the electronic nose should remain sealed before and after injection. The volume or mass of the sample is precisely measured and pre-sealed in one or more injection compartments, which are then placed inside the sensor chamber. When injection is required, the corresponding injection compartment is opened, and the sample is delivered to the sensor chamber, completing the injection operation. Methods such as large-volume evaporation, heating, and active gas circulation are used to rapidly evaporate the sample throughout the entire chamber. To achieve the aforementioned objectives, this invention provides a design method for a rapid quantitative injection device for volatile organic compounds (VOCs) within an electronic nose gas chamber. This injection device is suitable for accurately generating relatively low volumetric concentrations of VOC gas within a large-volume electronic nose gas chamber.

[0021] The overall design concept of the sample introduction device in this invention is as follows: quantitative measurement (volume or weight) of VOCs is performed outside the electronic nose gas chamber. These measured VOCs (liquid or solid) are sealed in one or more sample introduction chambers and placed inside the electronic nose gas chamber. When sample introduction is needed, an opening command is issued from outside the electronic nose gas chamber, and an actuator completes the opening task of the sample introduction device, allowing VOCs to evaporate into the electronic nose gas chamber without compromising its airtightness. In this design, the volume of the electronic nose gas chamber is much larger than the volume of the sample introduction chambers, thus enabling rapid VOC evaporation under large volume conditions. A heating device is installed on the sample introduction chambers to heat the VOCs before or after the sample introduction device is opened, further accelerating the VOC evaporation rate. A ventilation device is installed next to the sample introduction chambers to accelerate the surrounding gas flow after the sample introduction device is opened, thereby accelerating the evaporation and diffusion rates.

[0022] In order to generate gaseous VOC samples with precise concentrations, this invention first requires accurately measuring the required volume or mass of the VOC sample. Precision measuring instruments and high-precision injection needles are used to accurately measure the volume of the VOC sample, or a high-precision balance is used to accurately measure the mass of the VOC.

[0023] The sample injection chamber in this invention is relatively small in volume, designed to minimize the remaining air volume after placing the target volume or mass of VOC. Different volumes of injection chambers can be used in experiments with different concentration levels to achieve this objective. The main body and lid of the sample injection chamber are made of materials capable of withstanding internal and external pressure differences (such as atmospheric pressure), such as stainless steel. The lid of the sample injection chamber is connected to the main body using a spring-loaded hinge, ensuring that the lid remains open after being opened.

[0024] In this invention, the airtightness of the sample injection chamber is crucial. From the time VOCs enter the chamber until they need to be released, the chamber must ensure that the internal VOCs do not volatilize to the outside, causing sample loss or premature release. A rubber stopper is used to seal the body of the sample injection chamber and the lid. Pressure is applied to the outside of the lid of the sample injection chamber by an actuator to fully compress the rubber stopper.

[0025] To ensure the actuator fully compresses the rubber stopper, this invention employs an auxiliary clamping device. After the clamping device clamps the hatch cover, the actuator is then controlled to lock the hatch cover. At this point, the clamping device releases the cover, completing the auxiliary clamping process.

[0026] The sample introduction device is placed in the sensor chamber and is connected to the host computer controlling the actuator via a gas-tight connector. The gas-tight connector is mounted on the wall of the sensor chamber, enabling signal communication between the inside and outside of the chamber while ensuring airtightness. When the host computer sends an actuator open signal, the actuator performs an unlocking action, causing the sample introduction chamber cover to pop open and allowing VOCs to begin evaporating into the chamber.

[0027] The injection device is equipped with a heating element and a temperature sensor. Heating and temperature control of the injection device can be activated under the control of a host computer. This can be activated before injection to preheat and evaporate liquid or solid VOCs into a gaseous state, facilitating rapid diffusion after injection begins. Alternatively, heating can be initiated after injection begins to control the evaporation of VOCs at the desired rate.

[0028] A ventilation device (such as a fan) is installed next to the sample injection device to accelerate the flow of gas around the sample injection device, reduce the concentration of surrounding samples, thereby accelerating the evaporation rate and helping to achieve uniform diffusion of samples within the device.

[0029] Multiple injection devices can be placed in the entire gas chamber to store VOCs of different volumes (or masses) or different types of VOCs. They can be opened and injected separately when needed to achieve the generation of stepped concentrations or the generation of a mixed environment in the gas chamber.

[0030] The sensor chamber mainly contains a gas sensor array, and also has a device to help the odor diffuse evenly.

[0031] The specific experimental steps for VOC gas injection in this invention are as follows: Step 1: Use precision measuring instruments and high-precision injection needles to accurately measure VOC samples; Step 2: Place the VOCs into the appropriate volume of the injection device compartment; Step 3: Use the auxiliary clamping device to clamp the sample injection chamber, lock the actuator, and place the sample injection device in the electronic nose gas chamber; Step 4: If preheating is required, turn on the heating and temperature control devices of the injection device in advance to allow the VOCs to evaporate into a gaseous state; Step 5: When sample injection is required, a control signal is sent from the host computer to the actuator, which then performs the unlocking and closing action to open the sample injection chamber; Step 7: If necessary, turn on the heating and ventilation devices to accelerate the evaporation and diffusion rate; Step 8: Observe through the observation window of the sensor's gas chamber. All VOCs have evaporated into gaseous VOCs, and there are no residues in the sample injection device.

[0032] Example: Figure 1 This is a schematic diagram showing the structural relationship between the sample introduction device and the electronic nose air chamber in this embodiment. Figure 2 , Figure 3 and Figure 4 These are, respectively, a top view, a side view, and a three-dimensional structural schematic diagram of the sample introduction device in this embodiment.

[0033] After the precisely measured VOCs are sealed and stored in the injection device 24, the injection device 24 is placed inside the electronic nose air chamber 20. The injection device 24 interacts with the host computer via the airtight connector 23. The servo motor 9 and the servo arm 12 constitute the actuator. The host computer sends a command to open the injection chamber cover 13 through the airtight connector to the servo motor 9. The servo motor 9 controls the servo arm 12 to rotate clockwise, and the injection chamber cover 13 opens under the elastic force of the hinge 4, thereby initiating the VOC evaporation and injection. The evaporation process can be observed through the observation window 22 installed on the door 21 of the air chamber 20. The gas sensor array 25 is located inside the electronic nose air chamber 20 and can directly sense the dynamic diffusion process of VOCs. With the help of the auxiliary odor diffusion homogenization device 26, the gas sensor array 25 can also sense the state after the gaseous VOCs are evenly distributed. The hinge connection device 10 fixes the hinge to the base plate by the nut 1 and the stud 14.

[0034] The sample introduction device 24 in this embodiment consists of a sample introduction chamber 18, servo motors 9, and a support device 17. The sample introduction chamber 18 has a small volume, and its sealing is ensured by a chamber cover 13 and a rubber stopper 8. The automatic opening of the sample introduction chamber cover 13 is ensured by a hinge 4. The sample introduction chamber 18 is mounted on the support device 17 by screws 1 and 2. This embodiment includes two servo motors 9, which are mounted on the support device 17 by screws 3. The main body of the servo motor 9 is relatively high, so studs 14 are used to balance and support the height of the servo motor 9. The servo motor arm 12 of the servo motor 9 includes two screws. Screws 15 fix the servo motor arm 12 to the servo motor 9, and screws 16 are used to adjust the distance between the servo motor arm and the chamber cover, thereby adjusting the tightness of the rubber stopper of the chamber cover.

[0035] In this embodiment, a heating film is installed at the bottom of the sample introduction device 24, that is, at the bottom of the main body of the sample introduction chamber 18. The function of the heating film is to heat the solid or liquid VOC to a temperature above the boiling point before sample introduction, so that it can evaporate into a gaseous state in advance, or to increase the temperature of the unevaporated VOC after sample introduction, so as to accelerate the evaporation process and thus increase the sample introduction speed.

[0036] When the sample injection begins, the sample injection chamber cover 13 is opened, and the ventilation device 27 is turned on to blow the VOC vapor above the sample injection chamber 18 into other spaces of the gas chamber, accelerating the flow of VOC samples and thus achieving the effect of rapid sample diffusion.

[0037] In this embodiment, a precision measuring instrument and a high-precision injection needle are used to accurately measure the volume of liquid VOCs. The precision measuring instrument is a micro-injection pump that can accommodate multi-range glass injection needles, and this injection pump has an excellent control system and a precise mechanical structure.

[0038] In this embodiment, an auxiliary clamping device, specifically a small manual press, is used to ensure that the rubber stopper of the sample inlet chamber 18 is fully compressed. This press consists of a force-saving spring, an adjusting stroke screw, a machine support, a rack, a non-slip handle, and a pressing column. It can assist in clamping the rubber stopper of the sample inlet chamber 18 with relatively small pressure applied to the handle, allowing the servo arm 12 to easily clamp the sample inlet chamber 18 and prevent VOC gas from evaporating to the outside of the sample inlet chamber 18.

[0039] In this implementation example, the specific steps for precise and rapid VOC injection into the sensor chamber of the electronic nose are as follows: Figure 5 As shown, the specific explanation is as follows: Step S1: Use precision measuring instruments and high-precision injection needles to accurately measure the volume of liquid VOCs; Step S2: Place the liquid VOC into the small chamber of the injection device; Step S3: Use the auxiliary clamping device to press the rubber stopper of the sample inlet chamber, and then use the servo arm to press the cover of the sample inlet chamber. Step S4: Place the sample introduction device in the electronic nose air chamber; Step S5: When sample injection is required, a control signal is sent from the host computer to the servo motor, which controls multiple servo motor arms to rotate and open the sample injection chamber. Step S6: Observe through the observation window of the sensor chamber. After all liquid VOCs have turned into gaseous VOCs, start the electronic nose odor sensing task.

[0040] This implementation example uses high-precision measuring instruments to accurately measure VOC samples, and uses an auxiliary clamping device and a servo arm to ensure that the VOC samples are sealed in the injection device. When it is necessary to release the sample into the electronic nose air chamber, it is not necessary to break the seal of the electronic nose air chamber. The injection device can be opened by controlling the external control signal, thus realizing the rapid injection of VOC samples into the electronic nose air chamber.

Claims

1. A rapid quantitative sample introduction device within an electronic nasal air chamber, characterized in that, Includes hinges, rubber plugs, servo motors, servo motor arms, sample inlet chamber cover, studs, support devices, and sample inlet chamber; The sample inlet chamber is mounted on a support device; The rubber stopper and sample inlet chamber cover are used to seal the sample inlet chamber; The servo motor is mounted on a support device; The servo arm has two screws. One screw fixes the servo arm to the servo motor, and the other screw is used to adjust the distance between the servo arm and the sample inlet chamber cover, thereby adjusting the tightness of the rubber stopper. The servo motor and servo arm constitute the actuator. The servo motor controls the servo arm to rotate clockwise, and the sample inlet cover opens under the elastic force of the hinge, thereby enabling VOC to be volatilized and injected. The stud is used to balance and support the height of the servo motor.

2. The rapid quantitative sample introduction device in an electronic nasal air chamber according to claim 1, characterized in that, The sample introduction device is placed inside the electronic nose air chamber; the sample introduction device interacts with the host computer via an airtight plug on the electronic nose air chamber.

3. The rapid quantitative sample introduction device in an electronic nasal air chamber according to claim 1, characterized in that, The bottom of the sample injection chamber is equipped with a heating device, which is used to heat solid or liquid VOCs to a temperature above the boiling point before sample injection, so that they can evaporate into a gaseous state in advance, or to increase the temperature of unevaporated VOCs after sample injection, so as to accelerate the evaporation process and thus increase the sample injection speed.

4. The rapid quantitative sample introduction device in an electronic nasal air chamber according to claim 1, characterized in that, The heating device is a heating film.

5. The rapid quantitative sample introduction device in an electronic nasal air chamber according to claim 1, characterized in that, The sample injection device is also equipped with an auxiliary clamping device to ensure that the rubber stopper fully clamps the sample injection chamber 18.

6. The rapid quantitative sample introduction device in an electronic nasal air chamber according to claim 1, characterized in that, The auxiliary clamping device is a small manual press; the press includes a force-saving spring, an adjusting stroke screw, a machine support, a rack, an anti-slip handle, and a pressing column, which can assist in clamping the sample inlet chamber with a rubber plug at the anti-slip handle, so that the servo arm clamps the sample inlet chamber and prevents VOC gas from evaporating to the outside of the sample inlet chamber.

7. The rapid quantitative sample introduction device in an electronic nasal air chamber according to claim 1, characterized in that, The actuators consist of two sets.

8. A rapid quantitative sample introduction device in an electronic nasal air chamber according to claim 1, characterized in that, A ventilation device is installed next to the sample introduction device, which can accelerate the flow of gas around the sample introduction device, reduce the concentration of surrounding samples, thereby accelerating the volatilization rate and helping to achieve uniform diffusion of the indoor samples.

9. A rapid quantitative sample introduction device in an electronic nasal air chamber according to claim 1, characterized in that, The sampling device has multiple components, which can store different volumes or masses of VOCs, or different types of VOCs. They can be turned on and injected separately when needed to achieve the generation of stepped concentrations in the gas chamber or the generation of a mixed environment.

10. A quantitative injection method using the rapid quantitative injection device as described in claim 1, characterized in that, Includes the following steps: Step 1: Use precision measuring instruments and high-precision injection needles to accurately measure the volume of liquid VOCs; Step 2: Place the liquid VOC into the sample injection chamber; Step 3: Use the auxiliary clamping device to press the rubber stopper, and then use the servo arm to press the sample inlet chamber cover; Step 4: Place the sample introduction device in the electronic nose air chamber; Step 5: If preheating is required, turn on the heating device in advance to allow the VOCs to evaporate into a gaseous state; Step 6: When sample injection is required, a control signal is sent from the host computer to the servo motor, which controls the servo motor arm to rotate and open the sample injection chamber. Step 7: If necessary, turn on the heating and ventilation devices to accelerate the evaporation and diffusion rate; Step 8: Observe through the observation window of the electronic nose air chamber. After all the liquid VOCs have turned into gaseous VOCs, start the electronic nose odor perception task.

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