Soil water content calibration device

Abstract

The utility model discloses a soil water content calibration device which comprises a workbench, a container, pressure equipment and collection equipment, the workbench comprises an upper supporting plate and a lower supporting plate, the container is located on the workbench and used for containing soil, the pressure equipment is located in the container and used for applying pressure to compact the soil, and the collection equipment is used for collecting the water content of the soil. One end of the collecting equipment is positioned in the soil, and the other end is electrically connected with the control system. In the application, through the combined design of the workbench, the pressure equipment and the acquisition equipment, the water content change of the soil under different environmental conditions can be simulated, so that the accuracy of the soil moisture data is ensured, and the homogeneity of the soil after backfilling is improved. In addition, the device is integrated with a data acquisition system, soil water content data measured by a sensor are automatically read and collected through programming, and the calibration precision and efficiency are further improved.

Description

Technical Field

[0001] This utility model relates to the field of soil measurement technology, and in particular to a soil moisture content calibration device. Background Technology

[0002] In soil science research and agricultural engineering, accurately obtaining soil moisture content is of great significance for understanding crop growth processes, studying soil moisture movement patterns, and predicting pollutant migration. Currently, methods for obtaining soil moisture content are mainly divided into direct methods and indirect methods. Direct methods are represented by the oven-drying method, while indirect methods include neutron detector methods, dielectric methods (such as time-domain reflectometry and frequency-domain reflectometry), cosmic ray neutron methods, geophysical methods (such as ground-penetrating radar and high-density resistivity methods), and thermal pulse methods.

[0003] In recent years, soil moisture sensors have become the mainstream tool for measuring soil moisture content due to their data continuity, efficiency, and security. Since the accuracy of soil moisture sensors varies under different soil conditions, calibration is required to improve measurement accuracy before use. The traditional calibration process includes soil sample processing, moisture content gradient configuration, backfilling and bulk density restoration, recording sensor output values, establishing calibration curves, and verification and optimization.

[0004] However, this manual calibration method suffers from problems such as cumbersome operation, time consumption, and poor soil homogeneity and bulk density recovery, making it difficult to meet the needs of frequent calibration and large-scale experiments. Furthermore, existing soil moisture content calibration devices generally lack the ability to precisely control bulk density and apply uniform pressure, failing to realistically simulate the soil environment and affecting calibration accuracy and reliability. Therefore, developing a device capable of precisely controlling the backfilling process and rapidly completing moisture content calibration is of great significance for improving the accuracy and efficiency of soil moisture content measurement and promoting soil research and agricultural practice. Utility Model Content

[0005] To address the common problems of existing soil moisture content calibration devices lacking precise control of bulk density and uniform pressure application, thus failing to realistically simulate the soil environment and affecting calibration accuracy and reliability, this invention provides a soil moisture content calibration device. The technical solution adopted is as follows:

[0006] A soil moisture content calibration device, comprising:

[0007] The workbench has an upper support plate and a lower support plate;

[0008] A container, located on the workbench, is used to hold soil;

[0009] A pressure device, located inside the container, is used to apply pressure to compact the soil.

[0010] A data acquisition device, one end of which is located in the soil and the other end is electrically connected to a control system.

[0011] In some embodiments, the pressure device includes a hydraulic jack and a cover plate, the hydraulic jack abutting against the upper support plate and the cover plate being located on top of the soil.

[0012] In some embodiments, the cover plate is provided with a plurality of vent holes and a handle, the plurality of vent holes extending along the thickness direction of the cover plate, and the handle being located on the top surface of the cover plate.

[0013] In some embodiments, the container is a cylindrical structure made of plexiglass.

[0014] In some embodiments, the outer wall of the container is provided with a scale, the scale is spaced apart along the height direction of the container, and the scale protrudes axially toward the container.

[0015] In some embodiments, the data acquisition device includes a data acquisition unit and a moisture sensor, wherein the input terminal of the data acquisition unit is connected to the moisture sensor and the output terminal is electrically connected to the control system.

[0016] The moisture sensor portion is placed within the soil.

[0017] In some embodiments, the thickness of the soil along the height of the container is 10 cm greater than the length of the moisture sensor.

[0018] The technological advancements achieved by this invention compared to existing technologies are as follows:

[0019] This invention, through the combined design of a workbench, pressure device, and data acquisition device, can simulate soil moisture content changes under different environmental conditions, thereby ensuring the accuracy of soil moisture data and improving the homogeneity of the soil after backfilling. Furthermore, the device integrates a data acquisition system that automatically reads and collects soil moisture content data measured by sensors through programming, further improving the accuracy and efficiency of calibration. Attached Figure Description

[0020] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0021] In the attached diagram:

[0022] Figure 1 This is a structural diagram of the soil moisture content calibration device of this utility model;

[0023] Figure 2This is a schematic diagram of the soil moisture content calibration device of this utility model;

[0024] Figure 3 This is a partial schematic diagram of the soil moisture content calibration device of this utility model;

[0025] Figure 4 This is a schematic diagram of the container in this utility model;

[0026] Figure 5 This is a schematic diagram of the cover plate in this utility model;

[0027] Figure 6 This is a schematic diagram of the soil moisture content calibration device of this utility model;

[0028] Figure 7 This is a partial structural diagram of the soil moisture content calibration device of this utility model.

[0029] In the diagram: 1. Workbench; 11. Upper support plate; 12. Lower support plate; 13. Bracket; 2. Container; 21. Hole; 22. Ruler; 3. Pressure equipment; 31. Hydraulic jack; 32. Cover plate; 321. Vent hole; 322. Handle; 4. Data acquisition equipment; 41. Data acquisition device; 42. Moisture sensor; 5. Soil; 6. Control system. Detailed Implementation

[0030] The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this utility model will be described below with reference to the accompanying drawings.

[0031] like Figures 1 to 7 As shown, this utility model discloses a soil moisture content calibration device, including a workbench 1, a container 2, a pressure device 3, and a data collection device 4. The workbench 1 has an upper support plate 11 and a lower support plate 12, which are connected by multiple supports 13 along the height direction of the supports 13 (e.g., along the height direction of the supports 13). Figure 1 As shown in the z-direction), the upper support plate 11 and the lower support plate 12 are spaced apart and are both square structures. During the use of the device, the operator places the equipment to be calibrated (such as container 2, pressure equipment 3, and acquisition equipment 4) on the upper support plate 11 or the lower support plate 12. The workbench 1 provides stable support to facilitate subsequent vertical backfilling of soil 5 and testing. In one example, the distance between the upper support plate 11 and the lower support plate 12 can be adjusted according to the operator's needs to adapt to different sizes of containers 2 or calibration requirements. At the same time, the workbench 1 is made of high-strength materials, such as high-strength steel plates and stainless steel. The high-strength material of the workbench 1 can ensure that no deformation or displacement occurs during the backfilling process, thereby ensuring uniform backfilling of soil.

[0032] Continue to refer to Figures 1 to 7 The soil moisture content calibration device also includes a container 2, which is located on the workbench 1. The interior of the container 2 is used to hold the backfill soil 5. The container 2 can be a cuboid structure or a cylindrical structure so that the pressure can be evenly distributed on the surface of the soil 5 when applied. In one example, the bottom of container 2 has multiple holes 21. When backfilling soil 5, the operator first places a qualitative filter paper at the bottom of container 2. The size of the qualitative filter paper is the same as the inner diameter of container 2. Then, soil 5 is backfilled into container 2. The holes 21 make the soil 5 in container 2 permeable, breathable and water-retaining, ensuring the accuracy of subsequent moisture content calibration. Pressure device 3 is located inside container 2. Pressure device 3 is used to apply pressure to compact soil 5. By adjusting the applied pressure intensity, pressure device 3 can simulate the compaction degree of soil 5 under different environmental conditions. The soil moisture content calibration device also includes a data acquisition device 4. One end of data acquisition device 4 is located inside soil 5, and the other end is electrically connected to control system 6. Data acquisition device 4 is used to monitor the changes in soil moisture content, temperature and humidity in real time. Data acquisition device 4 can be a soil moisture sensor, temperature sensor and moisture sensor, etc., and can be adapted as needed. After data acquisition, the data is processed by control system 6 to obtain soil moisture content and perform corresponding analysis.

[0033] This application, through the combined design of a workbench, pressure device, and data acquisition device, can simulate soil moisture content changes under different environmental conditions, thereby ensuring the accuracy of soil moisture data and improving the homogeneity of the soil after backfilling. Furthermore, the device integrates a data acquisition system that automatically reads and collects soil moisture content data measured by sensors through programming, further improving the accuracy and efficiency of calibration.

[0034] In some embodiments, such as Figures 1 to 2As shown, a pressure device 3 is installed on the workbench 1. The pressure applied by the pressure device 3 can be transmitted to the soil 5, so that the soil 5 achieves the expected compaction effect. The pressure device 3 includes a hydraulic jack 31 and a cover plate 32. The hydraulic jack 31 abuts against the upper support plate 11 and generates controllable strong pressure through the hydraulic system. The hydraulic jack 31 has a precise pressure control function, which can gradually apply pressure to accurately control the backfill thickness and bulk density of the soil 5, thereby improving the accuracy of the data acquisition device 4 calibration. It can also adjust the applied pressure according to the needs to simulate the state of the soil 5 under different stress conditions. The cover plate 32 is located on top of the soil 5. When the soil moisture content calibration device is used, after the operator backfills the required soil 5 into the container 2, the cover plate 32 is placed on top of the soil 5 and placed on the lower support plate 12. At the same time, the hydraulic jack 31 is placed on the cover plate 32. The operator presses the cover plate 32 so that the top of the hydraulic jack 31 is pressed against the bottom of the upper support plate 11, so that the bottom of the hydraulic jack 31 provides a reaction force to the cover plate 32, thereby compacting the soil 5 downward. That is, the vertical pressure generated by the hydraulic jack 31 is evenly transmitted to the soil 5 through the cover plate 32, and the soil 5 is accurately backfilled to its original bulk density. Since the cover plate 32 has a flat surface, it can ensure the uniformity of pressure distribution and stabilize the surface of the soil 5, thereby ensuring the accuracy of subsequent soil moisture content collection and analysis, and avoiding pressure concentration in one place, which would lead to uneven distribution of the soil 5.

[0035] In some embodiments, such as Figures 3 to 5 As shown, the cover plate 32 is provided with multiple vent holes 321 and a handle 322. The multiple vent holes 321 extend along the thickness direction of the cover plate 32. The number of vent holes 321 can be five or eight, as long as the soil 5 is breathable. This will not be elaborated on in this application. The handle 322 is located on the top surface of the cover plate 32. The shape of the handle 322 can be U-shaped or arc-shaped, as long as it is convenient for the operator to grip and lift the cover plate 32. In one example, continue to refer to Figures 3 to 5 The cover plate 322 has two handles, both U-shaped, which allow operators to place the cover plate 32 on top of the soil 5 or remove it from the container 2, thus ensuring both convenience and safety. The cover plate 32 is made of sturdy stainless steel or iron plate, which can evenly distribute the pressure applied by the hydraulic jack 31 to the surface of the soil 5 during use, ensuring that the backfilled soil 5 is uniform and without obvious stratification.

[0036] In some embodiments, such as Figures 1 to 5As shown, container 2 is a cylindrical structure of plexiglass. Plexiglass has the characteristics of high transparency and good toughness. When soil is backfilled into container 2, the operator can directly observe the state and volume of soil 5, which is convenient for timely adjustments later. In one example, the thickness of both container 2 and cover plate 32 is 2cm, and cover plate 32 matches container 2. That is, cover plate 32 is a cylindrical structure, thereby ensuring the sturdiness during use and the accuracy of subsequent data measurement.

[0037] In some embodiments, such as Figure 3 and Figure 6 As shown, the outer wall of container 2 is equipped with a scale 22, which can accurately accommodate the backfill soil 5 as needed, thereby improving the accuracy and reliability of data measurement. The scale 22 is evenly spaced along the height direction of container 2, and the scale 22 protrudes towards the axial direction of container 2. The protruding scale 22 ensures that the operator can clearly and intuitively read the scale value, reducing the measurement error caused by changes in viewing angle or light. It also helps with tactile perception, allowing the operator to quickly and accurately locate the required measurement point.

[0038] In some embodiments, such as Figure 6 and Figure 7 As shown, the data acquisition device 4 includes a data acquisition unit 41 and a moisture sensor 42. The moisture sensor 42 is used to measure the moisture content of the soil 5 to be calibrated. The input end of the data acquisition unit 41 is connected to the moisture sensor 42, and the output end is electrically connected to the control system 6. The data acquisition unit 41 can automatically acquire the moisture content data of the soil 5 measured by the moisture sensor 42 through programming, and store or transmit the data to the control system 6.

[0039] During use, the operator places the moisture sensor 42 part into the soil 5 to obtain the soil 5 data, and transmits the data to the control system 6 through the data acquisition device 41 for subsequent processing and analysis. It should be noted that the control system 6 can be a programmable controller or a computer. In this application, the control system 6 is a computer, which is used to display the moisture content data collected by the data acquisition device 41 so that the operator can centrally process and analyze it.

[0040] In some embodiments, the thickness of the soil 5 is greater than the length of the moisture sensor 42, thereby ensuring the accuracy of measuring the moisture content of the soil 5. In one example, such as Figure 6 As shown, along the height direction of container 2 (e.g.) Figure 6As shown in the z-direction, the thickness of the soil 5 is 10 cm greater than the probe length on the moisture sensor 42, thus ensuring the accuracy of moisture measurement and the representativeness of the data. This avoids interference from the external environment and prevents the soil 5 from being too thin. The detection range of the moisture sensor 42 may be affected by the boundary environment (such as the bottom of the container 2 or the air), leading to data distortion.

[0041] The steps for using the soil moisture content calibration device of this application are as follows:

[0042] like Figures 1 to 7 As shown, soil sampling and processing are first carried out. Operators collect representative original soil samples (5) from the experimental area to be calibrated, remove impurities (such as plant residues, stones, etc.), and air-dry them. Soil 5 is sieved to ensure homogeneity. Then, its dry soil mass is determined using the drying method. Soil 5 samples with different moisture content gradients are prepared according to experimental requirements. A certain amount of water is evenly mixed into the weighed dry soil. After stirring evenly, it is left to stand for a period of time to allow the moisture to be evenly distributed in the soil 5. During the standing period, the prepared soil is wrapped or covered with plastic film to prevent moisture evaporation. Operators determine the backfill soil 5 thickness (h, cm) based on the probe length of the moisture sensor 42. Generally, the backfill soil 5 thickness should be at least 10 cm greater than the probe length of the moisture sensor 42. Then, a certain weight of soil 5 is weighed from the standing wet soil sample. The mass of the wet soil is recorded and placed in a microwave oven. Its mass moisture content (m, g / g) is measured using the drying method. Then, according to the target bulk density (h / g), the moisture content is determined. g / cm 3 ), using formula Calculate the actual volumetric water content (VWC, cm⁻¹) of the soil 5 to be tested. 3 / cm 3 ).

[0043] Next, the soil is weighed and initially backfilled. After determining the thickness (h, cm) of the backfill soil 5, a piece of qualitative filter paper with the same inner diameter as container 2 is placed inside container 2. The weight of the prepared moist soil with the correct moisture content is calculated using the formula M=V*ρ*(1+m), where M represents the weight of the backfill soil 5 thickness. The unit weight of the backfill soil is represented by 'm', and the moisture content of the prepared soil, measured using the oven-drying method, is represented by 'm'. The weighed wet soil is backfilled into container 2 in layers, each layer being approximately 3-5 cm thick. After each layer is backfilled, a tool is used to initially level the soil, ensuring that each layer is as uniform and flat as possible.

[0044] After precise backfilling, once all the soil 5 is placed in the backfill container 2, the pre-prepared cover plate 32 is placed on the surface of the soil 5, ensuring that the cover plate 32 is parallel to the surface of the soil 5 and fits tightly with the inner diameter of the container 2. The operator places the container 2 on the lower support plate 12 and adjusts its position so that the hydraulic jack 32 is in the center of the cover plate 32 and that the bottom of the hydraulic jack 32 is in uniform contact with the cover plate 32. The top of the hydraulic jack 32 is fixed by the fixing point of the lower support plate 12 of the workbench 1 to provide stable vertical pressure. The operator gradually operates the hydraulic jack 32 to apply vertical downward pressure. As the pressure increases, the cover plate 32 will gradually move downward, backfilling the soil 5 to the target thickness and original bulk density. During this process, the operator can precisely adjust the backfilling degree of the soil 5 by controlling the pressure of the hydraulic jack 32 until the predetermined backfilling requirements are met. The compacted soil 5 sample has uniform bulk density and good homogeneity.

[0045] Then, the moisture content sensor is calibrated. After the soil 5 is backfilled to the target thickness and bulk density, the operator moves the container 2 to the upper support plate 11 or the ground and immediately inserts the moisture sensor 42 vertically into the soil 5, ensuring that the probe of the moisture sensor 42 is fully embedded in the soil 5 and in close contact with the surface of the soil 5. The insertion depth of the moisture sensor 42 should match the thickness of the soil 5 to ensure measurement accuracy. The other end of the moisture sensor 42 is connected to a data acquisition unit 41, which automatically reads and records the volumetric moisture content data (V) measured by the moisture sensor 42 through programming. The data acquisition unit 41 can display the measurement results in real time and store the data or transmit it to the control system 6 (e.g., a computer) for further analysis. The above process is repeated, and multiple measurements are performed using soil 5 with different moisture content gradients. After each experiment, the moisture content of the moisture sensor 42 (e.g., V1, V2, ... V) is recorded. n ) and the actual volumetric water content of soil 5 (e.g., V1', V2', ... V n ').

[0046] Finally, the results were analyzed and verified. The water content output by the moisture sensor 42 in all experiments was compared with the corresponding volumetric water content. An appropriate mathematical model (such as linear regression) was used to fit the calibration curve. To verify the accuracy of the calibration curve, soil samples 5 that were not included in the calibration were selected for independent verification. The volumetric water content of these samples was measured, and the water content was predicted using the calibration curve. The difference between the predicted value and the actual value was checked to ensure the accuracy of the calibration.

[0047] After the work is completed, the device should be maintained and reused. After each experiment, thoroughly clean the soil residue in container 2 and backfill device to ensure that the device is clean and free of pollution. Pay special attention to the surface cleanliness of hydraulic jack 31 and cover plate 32 to maintain the uniformity of the backfilling process. Regularly check the performance of hydraulic jack 31 and the stability of workbench 1 to ensure that the device can work normally when used next. If wear or loosening of parts is found, they should be replaced or repaired in time to avoid affecting the results of subsequent experiments.

[0048] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of the claims of this utility model.

Claims

1. A soil moisture content calibration device, characterized in that, include: The workbench has an upper support plate and a lower support plate; A container, located on the workbench, is used to hold soil; A pressure device, located inside the container, is used to apply pressure to compact the soil. A data acquisition device, one end of which is located in the soil and the other end is electrically connected to a control system.

2. The soil moisture content calibration device according to claim 1, characterized in that, The pressure device includes a hydraulic jack and a cover plate, the hydraulic jack abutting against the upper support plate, and the cover plate being located on top of the soil.

3. The soil moisture content calibration device according to claim 2, characterized in that, The cover plate is provided with a plurality of vent holes and a handle. The plurality of vent holes extend along the thickness direction of the cover plate, and the handle is located on the top surface of the cover plate.

4. The soil moisture content calibration device according to claim 1, characterized in that, The container is a cylindrical structure made of plexiglass.

5. A soil moisture content calibration device according to claim 4, characterized in that, The outer wall of the container is provided with a scale, which is spaced apart along the height direction of the container and protrudes axially toward the container.

6. The soil moisture content calibration device according to claim 1, characterized in that, The data acquisition device includes a data acquisition unit and a moisture sensor. The input end of the data acquisition unit is connected to the moisture sensor, and the output end is electrically connected to the control system. The moisture sensor portion is placed within the soil.

7. A soil moisture content calibration device according to claim 6, characterized in that, Along the height direction of the container, the thickness of the soil is 10 cm greater than the length of the moisture sensor.

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