A soil volatile organic compound (VOCs) detector

Abstract

The utility model discloses a kind of soil volatile organic compounds (VOCs) detector, relating to soil detection technical field.The soil volatile organic compounds (VOCs) detector, including box, the box bottom is fixedly connected with universal wheel, the box bottom is opened with sampling port, the box top side is fixedly connected with motor, the motor output end is fixedly connected with lead screw, the box inner top is fixedly connected with guide rail, the lead screw is screw-threaded with slider, the slider bottom is fixedly connected with hydraulic lifting device, the hydraulic lifting device bottom is fixedly connected with fixed support, the fixed support bottom is fixedly connected with sampling drill, the sampling drill is slidably connected with lifting piston, cooperation through motor, lead screw, hydraulic lifting device etc. Component, the automatic movement of sampling drill, lifting and soil taking are realized, reduce manual operation, improve sampling efficiency and accuracy, especially suitable for field large batch sample collection.

Description

Technical Field

[0001] This utility model relates to the field of soil testing technology, and in particular to a soil volatile organic compound (VOCs) detector. Background Technology

[0002] Patent application CN202420751890.9 discloses a soil nutrient testing device. This device includes a testing box with a communication cable fixedly connected to one side and a soil moisture, temperature, and conductivity sensor fixedly connected to the other end. This addresses the problem of existing soil nutrient testing devices requiring additional cleaning tools after removing the sampling probe from the soil. This necessitates carrying more tools and causing inconvenience for personnel working outdoors. However, this solution fails to mention that volatile organic compounds (VOCs) in soil primarily originate from industrial wastewater discharge, pesticide application, and oil and gas leaks. These VOCs are toxic, irritating, and carcinogenic, and can pollute groundwater and air through soil infiltration and volatilization, posing a serious threat to the ecological environment and human health. Therefore, accurate and rapid detection of VOC content in soil is crucial.

[0003] Traditional soil VOCs testing typically requires manual on-site sampling, followed by bringing the samples back to the laboratory for analysis. Manual sampling is not only labor-intensive and inefficient, but VOCs are also easily lost through volatilization during sampling and sample transportation, leading to distorted test results. While laboratory testing offers higher accuracy, the process is complex and time-consuming, making it difficult to obtain test data promptly and thus failing to meet the needs of emergency monitoring and rapid screening for site pollution.

[0004] Some existing portable testing devices are insufficient in terms of the degree of automation of sampling and the integration of sampling and testing. They either require manual assistance to complete the sampling or require cumbersome operations after sampling before testing can be performed, which affects the testing efficiency and ease of use.

[0005] Therefore, the development of a highly automated, integrated sampling and detection, and mobile soil VOCs detector has become an urgent need in the field of soil pollution monitoring. Utility Model Content

[0006] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a soil volatile organic compound (VOCs) detector that can solve the above-mentioned problem.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a soil volatile organic compound (VOCs) detector, comprising a housing, universal wheels fixedly connected to the bottom of the housing, a sampling port opened at the bottom of the housing, a motor fixedly connected to one side of the top of the housing, a lead screw fixedly connected to the output end of the motor, the lead screw being rotatably connected to the housing, a guide rail fixedly connected to the top of the housing, the guide rail being rotatably connected to the lead screw, a slider threadedly connected to the lead screw, the slider being slidably connected to the guide rail, and a hydraulic lifting device fixedly connected to the bottom of the slider;

[0008] The bottom of the hydraulic lifting device is fixedly connected to a fixed bracket, the bottom of the fixed bracket is fixedly connected to a sampling drill, a lifting piston is slidably connected inside the sampling drill, and the top of the lifting piston is fixedly connected to the bottom of the fixed bracket.

[0009] A collection tank is fixedly connected to the bottom of the box, and an electric hinge is fixedly connected to the collection tank. The collection tank is rotatably connected to a lid through the electric hinge.

[0010] A nitrogen tank is fixedly connected to one side of the collection tank via a pipe, and an outlet pipe is fixedly connected to the other side of the collection tank. An adsorption heat desorption device is fixedly connected to one end of the outlet pipe.

[0011] A first control valve is provided between the gas outlet pipe and the adsorption heat desorption device, a detector is fixedly connected to one end of the gas outlet pipe, and a second control valve is provided between the gas outlet pipe and the detector.

[0012] Preferably, the lifting piston is controlled by a hydraulic pump, which is fixedly connected to the inside of the housing.

[0013] Preferably, the bottom of the sampling drill is serrated.

[0014] Preferably, the collection tank is equipped with a heating device.

[0015] Preferably, the adsorption-thermal desorption device includes an adsorption tube, a heating wire, an exhaust pipe, and a solenoid valve.

[0016] Preferably, the air outlet pipe is a three-ended pipe.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] (1) The soil volatile organic compounds (VOCs) detector, through the cooperation of components such as motor, lead screw, and hydraulic lifting device, realizes the automatic movement, lifting and lowering of the sampling drill and soil sampling, reducing manual operation and improving sampling efficiency and accuracy. It is especially suitable for large-scale field sample collection. The equipment integrates functions such as sampling, sample processing and detection. Soil samples are collected and tested in the same equipment, reducing VOCs loss during sample transfer and ensuring the accuracy of test results.

[0019] (2) The soil volatile organic compounds (VOCs) detector is designed with a three-headed outlet pipe. By switching between the first control valve and the second control valve, it can be selected to detect after treatment by the adsorption heat desorption device or directly detect, so as to meet the detection needs of different concentrations and types of VOCs. The bottom of the box is fixedly connected with casters, which facilitates the movement of the equipment between different sampling points in the field and enhances the mobility and applicability of the equipment.

[0020] (3) The operation of each component of the soil volatile organic compound (VOCs) detector is adjusted by the corresponding control device. For example, the sampling depth can be precisely controlled by the hydraulic lifting device, and parameters such as heating temperature and nitrogen flow rate can be adjusted as needed to ensure that the detection process is stable and controllable. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0022] Figure 1 This is a schematic diagram of a soil volatile organic compound (VOCs) detector according to the present invention;

[0023] Figure 2 This is a schematic diagram of a soil volatile organic compound (VOCs) detector according to the present invention;

[0024] Figure 3 This is a cross-sectional schematic diagram of a soil volatile organic compound (VOCs) detector according to the present invention;

[0025] Figure 4 This is a cross-sectional schematic diagram of a soil volatile organic compound (VOCs) detector according to the present invention.

[0026] Reference numerals: 1. Box body; 2. Casters; 3. Sampling port; 4. Motor; 5. Guide rail; 6. Lead screw; 7. Slider; 8. Hydraulic lifting device; 9. Fixed bracket; 10. Lifting piston; 11. Sampling drill; 12. Collection tank; 13. Electric hinge; 14. Tank lid; 15. Nitrogen tank; 16. Gas outlet pipe; 17. First control valve; 18. Second control valve; 19. Adsorption heat desorption device; 20. Detector. Detailed Implementation

[0027] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0028] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0029] In the description of this utility model, terms such as greater than, less than, and exceeding are understood to exclude the stated number, while terms such as above, below, and within are understood to include the stated number. The use of terms like "first" and "second" is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the quantity or sequence of the indicated technical features.

[0030] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0031] Please see Figure 1-4 This utility model provides a technical solution: a soil volatile organic compound (VOCs) detector, including a box 1, universal wheels 2 fixedly connected to the bottom of the box 1, a sampling port 3 opened at the bottom of the box 1, a motor 4 fixedly connected to one side of the top of the box 1, a lead screw 6 fixedly connected to the output end of the motor 4, the lead screw 6 being rotatably connected to the box 1, a guide rail 5 fixedly connected to the top inside the box 1, the guide rail 5 being rotatably connected to the lead screw 6, a slider 7 threadedly connected to the lead screw 6, the slider 7 being slidably connected to the guide rail 5, a hydraulic lifting device 8 fixedly connected to the bottom of the slider 7, a fixed bracket 9 fixedly connected to the bottom of the hydraulic lifting device 8, a sampling drill 11 fixedly connected to the bottom of the fixed bracket 9, the bottom of the sampling drill 11 being serrated, a lifting piston 10 slidably connected inside the sampling drill 11, the lifting piston 10 being controlled by a hydraulic pump, and the top of the lifting piston 10 being fixedly connected to the bottom of the fixed bracket 9;

[0032] A collection tank 12 is fixedly connected to the bottom of the box 1. An electric hinge 13 is fixedly connected to the collection tank 12. The collection tank 12 is rotatably connected to the tank cover 14 through the electric hinge 13. A heating device is installed inside the collection tank 12. A nitrogen tank 15 is fixedly connected to one side of the collection tank 12 through a pipe. An exhaust pipe 16 is fixedly connected to the other side of the collection tank 12. The exhaust pipe 16 is a three-ended pipe. An adsorption heat desorption device 19 is fixedly connected to one end of the exhaust pipe 16. The adsorption heat desorption device 19 includes an adsorption tube, a heating wire, an exhaust pipe, and a solenoid valve. A first control valve 17 is provided between the exhaust pipe 16 and the adsorption heat desorption device 19. A detector 20 is fixedly connected to one end of the exhaust pipe 16. A second control valve 18 is provided between the exhaust pipe 16 and the detector 20.

[0033] During sampling, the motor 4 starts and drives the lead screw 6 to rotate. Since the slider 7 is threadedly connected to the lead screw 6 and constrained by the guide rail 5, the slider 7 slides along the guide rail 5, adjusting the sampling drill 11 to be directly above the sampling port 3. Then the hydraulic lifting device 8 extends, pushing the fixed bracket 9 and the sampling drill 11 to move downward, so that the sampling drill 11 passes through the sampling port 3 and inserts into the soil.

[0034] When the sampling drill 11 reaches the appropriate depth, the hydraulic pump controls the lifting piston 10 to slide upward inside the sampling drill 11, creating a negative pressure inside the sampling drill 11, which draws the soil sample into the sampling drill 11. Then, the hydraulic lifting device 8 retracts, causing the sampling drill 11 to rise above the collection tank 12. The lifting piston 10 slides downward, discharging the soil sample into the collection tank 12.

[0035] After the sample enters the collection tank 12, the electric hinge 13 drives the tank cover 14 to close the collection tank 12. The heating device inside the collection tank 12 is activated to heat the soil sample. At the same time, the nitrogen tank 15 introduces nitrogen into the collection tank 12 through the pipeline, causing the VOCs in the soil to volatilize and enter the gas outlet pipe 16 along with the nitrogen.

[0036] First, adsorption thermal desorption treatment is performed. The second control valve 18 is closed and the first control valve 17 is opened. The mixed gas enters the adsorption tube of the adsorption thermal desorption device 19. VOCs are adsorbed by the adsorption tube, and the remaining gas is discharged from the exhaust pipe. Then, the solenoid valve closes the exhaust pipe. After that, the heating wire of the adsorption thermal desorption device 19 heats the adsorption tube to desorb VOCs. Then, the first control valve 17 is closed and the second control valve 18 is opened. The desorbed gas enters the detector 20 for detection through the gas outlet pipe 16.

[0037] Working principle: This soil volatile organic compound detector uses a motor 4, a hydraulic lifting device 8, etc. as power sources, and completes soil sampling and VOCs detection through the coordinated operation of various components;

[0038] During sampling, the motor 4 starts and drives the lead screw 6 to rotate. Since the slider 7 is threadedly connected to the lead screw 6 and constrained by the guide rail 5, the slider 7 slides along the guide rail 5, adjusting the sampling drill 11 to be directly above the sampling port 3. Then the hydraulic lifting device 8 extends, pushing the fixed bracket 9 and the sampling drill 11 to move downward, so that the sampling drill 11 passes through the sampling port 3 and inserts into the soil.

[0039] When the sampling drill 11 reaches the appropriate depth, the hydraulic pump controls the lifting piston 10 to slide upward inside the sampling drill 11, creating a negative pressure inside the sampling drill 11, which draws the soil sample into the sampling drill 11. Then, the hydraulic lifting device 8 retracts, causing the sampling drill 11 to rise above the collection tank 12. The lifting piston 10 slides downward, discharging the soil sample into the collection tank 12.

[0040] After the sample enters the collection tank 12, the electric hinge 13 drives the tank cover 14 to close the collection tank 12. The heating device inside the collection tank 12 is activated to heat the soil sample. At the same time, the nitrogen tank 15 introduces nitrogen into the collection tank 12 through the pipeline, causing the VOCs in the soil to volatilize and enter the gas outlet pipe 16 along with the nitrogen.

[0041] Connect the outlet of nitrogen tank 15 to the pressure reducing valve via a high-pressure hose. Connect a gas filter (to remove trace impurities that may be present in the nitrogen) and a rotor flow meter in series at the outlet of the pressure reducing valve. Use a polytetrafluoroethylene filter element with a pore size of 0.2μm to ensure that the nitrogen purity reaches 99.999% or higher. Set the flow meter range to 0-500mL / min to facilitate precise control of the gas flow rate.

[0042] Connect the pipe at the outlet of the flow meter to the air inlet at the bottom of the collection tank 12. The pipe is made of stainless steel with silanization treatment on the inner wall (to avoid VOCs adsorption loss). Open the main valve of the nitrogen tank 15 and slowly adjust the pressure reducing valve to stabilize the output pressure at 0.2-0.3MPa. Set the nitrogen flow rate to 200-300mL / min using the flow meter knob. The gas is evenly sprayed out from the gas distribution plate (porous titanium plate with 1mm pore size) at the bottom of the collection tank 12, forming fine bubbles that penetrate through the soil sample layer, promoting the full volatilization of VOCs in the soil.

[0043] Install a pressure gauge at the air outlet on the top of the collection tank 12 to monitor the pressure inside the tank in real time (maintain a slight positive pressure of 5-10 kPa) to avoid excessive pressure leading to gas leakage. During the ventilation process, observe the disturbance state of the soil sample through the observation window on the side wall of the collection tank 12 to ensure that the nitrogen gas passes through the sample in a stable airflow without forming a violent impact (to prevent soil particles from entering the air outlet pipe 16 with the airflow). Continue ventilation for 30-60 minutes (adjust according to the amount of soil sample), and record the flow meter reading and the pressure inside the tank every 10 minutes during this period.

[0044] After the predetermined ventilation time is completed, the nitrogen flow rate is kept stable. The first control valve 17 is opened and the second control valve 18 is closed, allowing the nitrogen carrying VOCs to enter the adsorption thermal desorption device 19. At this time, the outlet of the collection tank 12 is connected to the inlet of the adsorption tube by switching through the three-way valve. The mixed gas flows through the adsorption tube (Φ6mm×150mm) filled with Tenax-TA adsorbent at a flow rate of 100-200mL / min. The VOCs are captured by the adsorbent, and the remaining nitrogen is discharged through the exhaust pipe (with an activated carbon tail gas treatment device installed at the end).

[0045] When the adsorption time reaches the set value (usually 30 minutes), the solenoid valve on the exhaust pipe is closed to achieve sealing, and the heating program of the adsorption thermal desorption device 19 is started. The adsorption tube is heated at 280℃ for 10 minutes (heating rate 50℃ / min) to completely desorb the adsorbed VOCs. After desorption is completed, the first control valve 17 is closed and the second control valve 18 is opened. At the same time, the carrier gas (high-purity helium, flow rate 30mL / min) is started to send the desorbed VOCs through the transfer line (maintained at 180℃ to prevent condensation) to the detector 20 (such as a gas chromatograph-mass spectrometer) for qualitative and quantitative analysis.

[0046] After the test, close the main valve of the nitrogen tank to release the residual pressure in the pipeline, and then close each control valve in sequence. Perform high-temperature aging on the adsorption tube (baking at 300℃ for 20 minutes), clean the residual soil inside the collection tank 12, and check the sealing of all connections to prepare for the next operation.

[0047] With the cooperation of components such as motor 4, lead screw 6, and hydraulic lifting device 8, the sampling drill 11 can move, lift and take soil automatically, reducing manual operation and improving sampling efficiency and accuracy. It is especially suitable for large-scale sample collection in the field.

[0048] The equipment integrates functions such as sampling, sample processing, and testing. Soil samples are collected and tested within the same device, reducing VOCs loss during sample transfer and ensuring the accuracy of test results.

[0049] The outlet pipe 16 is designed as a three-headed pipe. By switching between the first control valve 17 and the second control valve 18, it can be selected to be detected after being treated by the adsorption heat desorption device 19 or directly detected, so as to meet the detection needs of different concentrations and types of VOCs.

[0050] The bottom of the housing 1 is fixedly connected to casters 2, which facilitates the movement of the equipment between different sampling points in the field, enhancing the mobility and applicability of the equipment;

[0051] The actions of each component are adjusted through corresponding control devices. For example, the sampling depth can be precisely controlled by the hydraulic lifting device 8, and parameters such as heating temperature and nitrogen flow rate can be adjusted as needed to ensure that the detection process is stable and controllable.

[0052] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A soil volatile organic compound (VOCs) detector comprising a box (1), characterized in that: The bottom of the box (1) is fixedly connected with casters (2), the bottom of the box (1) is provided with a sampling port (3), the top side of the box (1) is fixedly connected with a motor (4), the output end of the motor (4) is fixedly connected with a lead screw (6), the lead screw (6) is rotatably connected to the box (1), the top of the box (1) is fixedly connected with a guide rail (5), the guide rail (5) is rotatably connected to the lead screw (6), the lead screw (6) is threadedly connected with a slider (7), the slider (7) is slidably connected to the guide rail (5), and the bottom of the slider (7) is fixedly connected with a hydraulic lifting device (8). The hydraulic lifting device (8) is fixedly connected to a fixed bracket (9) at the bottom, and a sampling drill (11) is fixedly connected to the bottom of the fixed bracket (9). A lifting piston (10) is slidably connected inside the sampling drill (11), and the top of the lifting piston (10) is fixedly connected to the bottom of the fixed bracket (9). A collection tank (12) is fixedly connected to the bottom of the box (1), and an electric hinge (13) is fixedly connected to the collection tank (12). The collection tank (12) is rotatably connected to a lid (14) through the electric hinge (13). A nitrogen tank (15) is fixedly connected to one side of the collection tank (12) via a pipe, and an outlet pipe (16) is fixedly connected to the other side of the collection tank (12). An adsorption heat desorption device (19) is fixedly connected to one end of the outlet pipe (16). A first control valve (17) is provided between the gas outlet pipe (16) and the adsorption heat desorption device (19), and a detector (20) is fixedly connected to one end of the gas outlet pipe (16).

2. The soil volatile organic compound (VOCs) detector according to claim 1, wherein: The lifting piston (10) is controlled by a hydraulic pump, which is fixedly connected to the inside of the housing (1).

3. The soil volatile organic compound (VOCs) detector according to claim 2, wherein: The bottom of the sampling drill (11) is serrated.

4. The soil volatile organic compound (VOCs) detector according to claim 3, wherein: A heating device is installed inside the collection tank (12).

5. The soil volatile organic compound (VOCs) detector according to claim 4, wherein: The adsorption heat desorption device (19) includes an adsorption tube, a heating wire, an exhaust pipe, and a solenoid valve.

6. The soil volatile organic compound (VOCs) detector according to claim 5, wherein: The exhaust pipe (16) is a three-headed pipe.

7. The soil volatile organic compound (VOCs) detector according to claim 6, wherein: A second control valve (18) is provided between the air outlet pipe (16) and the detector (20).

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