A multilayer gas gradient sampling device for monitoring in-situ nitrification-denitrification processes

Abstract

The utility model belongs to soil gas sampling technical field, especially relate to a multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring. Its technical scheme is: a multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring, including sampling needle, the multilayer sampling channel of being sequentially sleeved with in sampling needle, each layer sampling channel is connected with the lateral sampling port of inserting into soil, the depth of lateral sampling port on several layers sampling channel changes in turn, the gas hose of being connected with on each layer sampling channel, the other end of gas hose is connected with the three -way plug valve of outlet, the outlet of three -way plug valve is connected with the luer connector, and the luer connector is detachably connected with negative pressure sampling device, when transferring gas, negative pressure sampling device detachably connects the gas storage device. The utility model provides a multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring.

Description

Technical Field

[0001] This invention belongs to the field of soil gas sampling technology, and specifically relates to a multi-layer gas gradient sampling device for in-situ monitoring of nitrification-denitrification processes. Background Technology

[0002] Nitrous oxide (N2O) is a significant greenhouse gas with a global warming potential far exceeding that of carbon dioxide, and it is widely produced in farmland, grassland, and desert ecosystems. Soil is the primary source of N2O release, with its production mechanism mainly relying on microbially driven nitrification and denitrification processes. Nitrification primarily occurs in well-aerated topsoils, while denitrification is more common in deeper soils under anoxic or anaerobic conditions. Therefore, N2O generation and emission exhibit a significant depth gradient across soil profiles. Clarifying the contribution of different soil layers to N2O production is a crucial prerequisite for conducting nitrogen cycle research, greenhouse gas emission reduction management, and ecological modeling.

[0003] Currently, the main methods for studying N2O concentration in soil profiles are borehole sampling or single-point injection aeration. However, these methods have several problems. First, the aeration process often involves soil structure disturbance and gas exchange, leading to in-situ concentration distortion. Second, the sampling point layout is inaccurate and lacks repeatability, making it difficult to achieve simultaneous comparisons at multiple time points and depths. Third, the interfaces of sampling devices are not standardized, making them incompatible with different types of gas bags or online monitoring systems. Fourth, multiple sampling requires repeated operations, resulting in high labor costs and hindering long-term continuous field observations. Traditional sampling methods are particularly limited in easily disturbed areas such as arid and permafrost regions.

[0004] Therefore, there is an urgent need to develop a gas sampling device that can be inserted in situ, has a compact structure, standardized interfaces, is easy to operate, and supports multi-layer sampling and external acquisition equipment to meet the technical requirements for monitoring the concentration gradient of gases such as N2O in soil profiles. This invention, based on the analysis and solution of the above problems, proposes an integrated multi-layer gas sampling device that can be widely used in laboratory soil column culture, farmland experimental platforms, and in-situ profile sampling in the field, providing reliable technical support for quantitative analysis and flux assessment of the nitrification-denitrification pathway. Utility Model Content

[0005] In order to solve the above-mentioned problems in the existing technology, the purpose of this utility model is to provide a multi-layer gas gradient sampling device for monitoring in-situ nitrification-denitrification processes.

[0006] The technical solution adopted in this utility model is as follows:

[0007] A multi-layer gas gradient sampling device for monitoring in-situ nitrification-denitrification processes includes a sampling needle with multiple sampling channels sequentially nested inside. Each sampling channel is connected to a lateral sampling port inserted into the soil. The depth of the lateral sampling ports on several sampling channels varies sequentially. Each sampling channel is connected to a gas delivery hose, and the other end of the gas delivery hose is connected to a three-way stopcock valve. The outlet of the three-way stopcock valve is connected to a Luer interface, which is detachably connected to a negative pressure sampling device. When transferring gas, the negative pressure sampling device can be detachably connected to a gas storage device.

[0008] This invention achieves simultaneous gas sampling at multiple depths within a soil profile of 0–20 cm by constructing a multi-layered nested sampling channel structure. Each sampling port has a fixed location and defined depth, supporting undisturbed stratified extraction of soil gas samples. This accurately reveals the distribution gradient of N2O in the vertical soil profile, significantly improving the resolution of nitrogen transformation process monitoring. This integrated multi-point sampling design overcomes the limitations of the traditional "single needle-single port" structure, avoiding the disturbance risks associated with repeated insertion / removal or multiple drilling.

[0009] Each sampling channel of this invention is independently controlled via a three-way stopcock valve and a standard Luer interface, allowing for quick connection to syringes, negative pressure sampling pumps, or online sensors. This enables quantitative, continuous, and multi-time-point sampling, greatly improving operational flexibility and sampling efficiency.

[0010] This invention adopts a modular and standardized interface design, making it suitable for indoor soil column testing platforms and easily deployed in in-situ field monitoring scenarios. Its insertion depth visualization markers and high reusability significantly reduce sampling costs and manpower. Furthermore, the device supports integration with gas storage bags, online gas analyzers, and data acquisition systems, demonstrating excellent scalability and promising prospects for widespread application.

[0011] As a preferred embodiment of this utility model, the sampling needle is provided with height scale lines.

[0012] As a preferred embodiment of this utility model, the depths of the plurality of lateral sampling ports are 5cm, 10cm, 15cm, and 20cm, respectively.

[0013] As a preferred embodiment of this utility model, the negative pressure sampling device is a syringe or a negative pressure pump.

[0014] As a preferred embodiment of this utility model, it also includes a connector control module, a three-way plug valve connected to the connector control module, and the end of the air guide hose furthest from the sampling needle connected to the connector control module.

[0015] As a preferred embodiment of this utility model, the gas storage device is made of aluminum foil bag, PVF sampling bag or Tedlar bag.

[0016] As a preferred embodiment of this utility model, the sampling channel is made of polytetrafluoroethylene.

[0017] As a preferred embodiment of this utility model, the negative pressure sampling device is connected to the detachable gas storage device via a quick-connect connector.

[0018] As a preferred embodiment of this utility model, the amount of gas extracted by the negative pressure sampling device is 50-200 mL.

[0019] As a preferred embodiment of this utility model, the negative pressure sampling device can also be detachably connected to the analysis interface.

[0020] The beneficial effects of this utility model are as follows:

[0021] 1. This invention achieves simultaneous gas sampling at multiple depths within a soil profile of 0–20 cm by constructing a multi-layered nested sampling channel structure. Each sampling port has a fixed location and defined depth, supporting undisturbed stratified extraction of soil gas samples. This accurately reveals the distribution gradient of N2O in the vertical soil profile, significantly improving the resolution of nitrogen transformation process monitoring. This integrated multi-point sampling design overcomes the limitations of the traditional "single needle-single port" structure, avoiding the disturbance risks associated with repeated insertion / removal or multiple drilling.

[0022] 2. Each sampling channel of this utility model is independently controlled by a three-way stopcock valve and a standard Luer interface, which can be quickly connected to a syringe, a negative pressure sampling pump or an online sensor to achieve quantitative, continuous and multi-time point sampling, greatly improving the flexibility of operation and sampling efficiency.

[0023] 3. This utility model adopts a modular and standardized interface design, suitable for indoor soil column test platforms, and can also be easily deployed in in-situ monitoring scenarios in the field. Its insertion depth visualization markers and high reusability significantly reduce sampling costs and manpower. Furthermore, the device supports integration with gas storage bags, online gas analyzers, and data acquisition systems, demonstrating good scalability and promising prospects for widespread application. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0025] Figure 2 This is a schematic diagram of a nested vertical sampling needle structure;

[0026] Figure 3 This is a schematic diagram of the gas path connection structure;

[0027] Figure 4 This is a schematic diagram of the insertion application of the device in a soil column / field profile.

[0028] In the diagram: 1-Sampling needle; 2-Gas delivery hose; 3-Three-way stopcock valve; 4-Luer interface; 5-Negative pressure sampling device; 6-Gas storage device; 7-Connector control module; 11-Sampling channel; 12-Side sampling port. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0031] like Figures 1-4 As shown, the multi-layer gas gradient sampling device for in-situ nitrification-denitrification process monitoring in this embodiment includes a sampling needle 1. Multiple sampling channels 11 are sequentially nested within the sampling needle 1. Each sampling channel 11 is connected to a lateral sampling port 12 inserted into the soil. The depth of the lateral sampling ports 12 on the multiple sampling channels 11 varies sequentially. Each sampling channel 11 is connected to a gas delivery hose 2. The other end of the gas delivery hose 2 is connected to a three-way stopcock valve 3. The outlet of the three-way stopcock valve 3 is connected to a Luer connector 4. The Luer connector 4 is detachably connected to a negative pressure sampling device 5. When transferring gas, the negative pressure sampling device 5 is detachably connected to a gas storage device 6. The negative pressure sampling device 5 is a syringe or a negative pressure pump. The gas storage device 6 is made of an aluminum foil bag, a PVF sampling bag, or a Tedlar bag.

[0032] One set of multi-layer vertical sampling needles: This device is equipped with multiple embedded polytetrafluoroethylene (PTFE) sampling channels 11, which are equidistantly arranged in the integrated needle body at different depths (such as 5cm, 10cm, 15cm, 20cm). Each channel has a microporous lateral sampling port 12 at the corresponding height, and is fixed as a whole by a stainless steel protective sleeve to form a set of sampling needles, which has good orientation and structural stability.

[0033] Independent sampling channels 11 and three-way stopcock valves 3: Each sampling channel 11 is equipped with an independent air guide hose 2, leading to the connector control module 7. Each channel has a standard Luer interface 4 and a three-way stopcock valve 3, which can be connected to a sealed syringe for sampling or to a negative pressure pump for automatic continuous sampling. The multi-channel parallel design enables independent control of sampling depth without interference.

[0034] Standardized interface and modular collection system: The negative pressure sampling device 5 can be connected to aluminum foil gas bags, multi-layer membrane gas storage bags, or online analysis sensors via quick-connect connectors. The interface specifications are unified, supporting one-click connection or replacement, enhancing system adaptability and flexibility.

[0035] Working principle and operation method:

[0036] 1. Device pre-insertion and fixation:

[0037] In the field or soil column test platform, the sampling needle 1 is vertically inserted into the target soil profile area, so that the lateral sampling ports 12 at different depths correspond to the designed target layers. The scale lines on the outer side of the sampling needle 1 help to accurately control the insertion depth and repositioning operation.

[0038] 2. Sampling preparation:

[0039] The air guide hoses 2 leading out from each sampling channel 11 are centrally deployed to the external collection platform, connected to the stopcock valve, and sealed with a cap for later use.

[0040] 3. Sampling operation:

[0041] At the set sampling time points, open the corresponding stopcock valves of the target channels in sequence, and slowly extract a certain volume (e.g., 50-200 mL) of gas sample from the specified depth channel using a syringe or negative pressure pump. Then close the valves and connect the gas bag or analysis system for sample transfer or detection.

[0042] 4. Data Analysis:

[0043] By comparing changes in N2O concentration, oxygen content, and other data at different depths, the distribution of nitrification or denitrification intensity in each soil layer within the profile can be determined, enabling quantitative analysis and pathway modeling of microbial processes.

[0044] This invention breaks through the limitations of the traditional "single-point-single-channel" gas sampling structure, and for the first time integrates stratified gas sampling with undisturbed multi-channel control into one, and achieves highly modular and field-adaptive design, providing an efficient, stable and repeatable technical path for carrying out soil N2O gradient monitoring and process research.

[0045] Compared with existing technologies such as traditional single-point gas sampling needles, borehole sampling methods, or temporary cannulation methods, this utility model has significant advantages in terms of structural design, sampling accuracy, airtightness, and ease of operation. The specific technical effects are as follows:

[0046] First, this invention achieves simultaneous gas sampling at multiple depths within a soil profile of 0–20 cm by constructing a multi-layered nested sampling channel structure 11. Each lateral sampling port 12 has a fixed position and a defined depth, supporting undisturbed stratified extraction of soil gas samples. This accurately reveals the distribution gradient of N2O in the vertical soil profile, significantly improving the resolution of nitrogen transformation process monitoring. This integrated multi-point sampling design overcomes the limitations of the traditional "single needle-single port" structure, avoiding the disturbance risks caused by repeated insertion and removal or multiple drilling.

[0047] Secondly, each sampling channel 11 of this device is independently controlled via a three-way stopcock valve 3 and a standard Luer interface 4, allowing for quick connection to syringes, negative pressure sampling pumps, or online sensors. This enables quantitative, continuous, and multi-time-point sampling, greatly improving operational flexibility and sampling efficiency. The gas delivery system uses polytetrafluoroethylene (PTFE) material, which has excellent corrosion resistance and airtightness, effectively preventing cross-contamination of gases and external interference, ensuring the representativeness of the samples and the accuracy of experimental data.

[0048] Finally, this device adopts a modular and standardized interface design, making it suitable for indoor soil column testing platforms and easily deployed in in-situ monitoring scenarios. Its insertion depth visualization markers and high reusability significantly reduce sampling costs and manpower. Furthermore, the device supports integration with gas storage bags, online gas analyzers, and data acquisition systems, demonstrating excellent scalability and promising prospects for widespread application.

[0049] In summary, this invention is significantly superior to existing technologies in terms of sampling accuracy, operational efficiency, system airtightness, and adaptability. It can effectively meet the research needs of soil N2O gradient analysis, nitrification-denitrification process monitoring, and model construction, and has important scientific research value and practical application significance.

[0050] Example:

[0051] The multi-layer gas gradient sampling device of this utility model mainly consists of the following key modules: multi-layer sampling needle 1, PTFE sampling channel 11, lateral sampling port 12, gas guide hose 2, connector control module 7, three-way stopcock valve 3, Luer interface 4, vacuum sampler and gas storage device 6. Among them, the multi-layer sampling needle 1, PTFE sampling channel 11, three-way valve and Luer interface are essential core structures, while the gas storage device 6 and online analysis system are optional expansion structures.

[0052] I. Device Structure Description:

[0053] 1. Multilayer sampling needle assembly:

[0054] This component forms the main structure for inserting into the soil profile. The outer shell is made of stainless steel or engineering plastic and is used to secure and protect the internal sampling tube bundle. The sampling needle 1 is typically 25–30 cm long, suitable for most topsoil research needs. Graduation marks are located on the outer side of the needle to control the insertion depth and ensure accurate repositioning.

[0055] 2. PTFE sampling channel 11:

[0056] The tube bundle contains 4 to 6 polytetrafluoroethylene (PTFE) sampling tubes, corresponding to soil depths of 0–5 cm, 5–10 cm, 10–15 cm, and 15–20 cm, respectively. Each sampling tube has a lateral sampling port 12 at the corresponding depth position, which can achieve directional gas sampling through a stainless steel hole or filter cap structure to prevent pipe blockage and mud and water contamination.

[0057] 3. Connect air hose 2 to the three-way valve:

[0058] Each sampling channel 11 is led to the connector control module 7 via a gas delivery hose 2. A three-way stopcock valve 3 is installed at the front end of each gas delivery hose 2 for single-channel on / off control, ensuring that the operation does not interfere with each other. A standard Luer interface 4 is provided at the outlet of the stopcock valve, which can be directly connected to commonly used syringes, negative pressure pumps or sampling bags.

[0059] 4. Gas extraction equipment and gas storage system:

[0060] Users can optionally equip the device with a sealed syringe or an electric negative pressure pump as a vacuum gas sampler to transfer gas samples to a multi-layer membrane gas storage bag for preservation. It can also be linked with an online N2O sensor module to achieve real-time monitoring and data acquisition. The gas storage device 6 can be made of materials such as aluminum foil bags, PVF sampling bags, or Tedlar bags.

[0061] II. Operating Procedures:

[0062] 1. Insertion preparation:

[0063] Insert the device vertically into the target soil profile or soil column test apparatus until the sampling needle 1 is completely buried, with the sampling port position corresponding to the designed depth. Ensure that all scale lines are aligned with the ground surface or the top of the container, and confirm that the tube is stable and free from shaking.

[0064] 2. Interface connection:

[0065] Check that each air delivery hose 2 is sealed to the valve. Open the connector control module 7 and connect the channel corresponding to the required sampling layer to the syringe or negative pressure pump. Keep the valve closed for unused channels.

[0066] 3. Sampling operation:

[0067] Open the target layer valves sequentially and slowly extract a target volume (e.g., 50–200 mL) of soil gas sample using the negative pressure device. After extraction, close the valves and transfer the gas to the gas storage device 6 or the analysis interface.

[0068] 4. Data recording and resampling:

[0069] Multiple time points and repeated sampling can be performed according to the experimental design to record the gas concentration at the corresponding layer and time point, which can be used for subsequent research such as profile concentration gradient modeling and nitrogen conversion pathway analysis.

[0070] III. Optional Extension Structure Description:

[0071] Table 1. Optional extended structure table.

[0072]

[0073] As can be seen from the above specific embodiments, this utility model has the technical characteristics of clear structure, flexible use and strong compatibility. It can be widely applied to in-situ soil gas profile monitoring tasks in arid areas, farmland, greenhouses and in the field, and has important application value, especially in the quantitative study of nitrification-denitrification processes.

[0074] This utility model is not limited to the above-mentioned optional embodiments. Anyone can derive other forms of products under the guidance of this utility model. However, regardless of any changes made in its shape or structure, any technical solution that falls within the scope of the claims of this utility model shall be protected by this utility model.

Claims

1. A multilayer gas gradient sampling device for monitoring in-situ nitrification-denitrification processes, characterized in that: Includes a sampling needle (1), inside which are arranged multiple sampling channels (11), each sampling channel (11) is connected to a lateral sampling port (12) inserted into the soil, the depth of the lateral sampling ports (12) on several sampling channels (11) varies sequentially, each sampling channel (11) is connected to a gas guiding hose (2), the other end of the gas guiding hose (2) is connected to a three-way stopcock valve (3), the outlet of the three-way stopcock valve (3) is connected to a Luer interface (4), the Luer interface (4) is detachably connected to a negative pressure sampling device (5); when transferring gas, the negative pressure sampling device (5) is detachably connected to a gas storage device (6).

2. The multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring according to claim 1, characterized in that: The sampling needle (1) is provided with height scale lines.

3. The multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring according to claim 1, characterized in that: The depths of the several lateral sampling ports (12) are 5cm, 10cm, 15cm and 20cm respectively.

4. The multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring according to claim 1, characterized in that: The negative pressure sampling device (5) is a syringe or a negative pressure pump.

5. A multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring according to claim 1, characterized in that: It also includes a connector control module (7), a three-way plug valve (3) connected to the connector control module (7), and the end of the air guide hose (2) away from the sampling needle (1) connected to the connector control module (7).

6. A multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring according to claim 1, characterized in that: The gas storage device (6) is made of aluminum foil bag, PVF sampling bag or Tedlar bag.

7. A multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring according to claim 1, characterized in that: The material of the sampling channel (11) is polytetrafluoroethylene.

8. A multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring according to claim 1, characterized in that: The negative pressure sampling device (5) is connected to the detachable gas storage device (6) via a quick-connect connector.

9. A multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring according to claim 1, characterized in that: The negative pressure sampling device (5) extracts 50 to 200 mL of gas.

10. A multilayer gas gradient sampling device for in-situ nitrification-denitrification process monitoring according to any one of claims 1 to 9, characterized in that: The negative pressure sampling device (5) can also be detached and connected to the analysis interface.

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