Simple device for multi-range soil air permeability measurement

Abstract

The simple device comprises a portable gas source, a switching type multi-range gas metering module, a differential pressure gauge and a sample base with a hollow structure, a gas supply port of the portable gas source is connected with a gas inlet of the switching type multi-range gas metering module and is used for providing gas; a gas outlet of the switching type multi-range gas metering module is communicated with the interior of the sample base and is used for measuring gas flow; the top end of the sample base is breathable, and a soil cutting ring sample is placed at the top end of the sample base; the differential pressure gauge is communicated with the interior of the sample base and used for measuring the pressure difference inside and outside the system. Gas flow meters with different measuring ranges can be rapidly switched according to the air permeability of different soil samples, so that accurate measurement of different gas flow ranges is achieved, measurement errors are reduced, all parts are easy to assemble, low in cost and independent, all pipeline connector parts are pneumatic rapid connectors and convenient to disassemble, the maintenance cost of the device is reduced, and the device is suitable for large-scale popularization and application. The operation is simple.

Description

Technical Field

[0001] The invention relates to the technical field of soil detection, in particular to a simple device for measuring multi-range soil air permeability. Background Art

[0002] Soil permeability refers to the ability of soil to allow air to pass through, and it is an important indicator of soil physical properties. Good soil permeability is the basis for the health of the soil ecosystem. It not only helps the normal respiration and growth of plant roots and enhances plant resistance, but also provides a suitable growth environment for microorganisms, enabling them to convert organic matter into nutrients that can be used by plants. In addition, soil permeability also affects soil water infiltration and runoff processes, and is directly related to environmental issues such as soil erosion and land degradation. When soil permeability deteriorates, the respiration of crop roots is restricted, resulting in a decrease in yield and quality, which in turn affects the sustainability of agricultural production.

[0003] Soil permeability is a comprehensive indicator that reflects the basic physical properties of soil, such as texture, porosity and structure. Soil permeability not only directly affects the effectiveness of soil water and nutrients, but also has an important impact on the growth and yield of crops. Therefore, studying soil permeability has important theoretical and practical significance in the field of agriculture. In soil science, soil permeability is usually expressed as the gas flux through a unit cross section under a pressure difference of 100 Pa (1 cm water column). However, traditional methods for measuring soil permeability, such as the constant pressure method and the pressure gauge method, each have some limitations. These include complex equipment, high cost, poor portability, limited measurement accuracy and poor adaptability, and there are limitations in measuring soils with heavy texture and poor permeability. Therefore, it is urgent to develop new technical devices according to specific needs and conditions to improve the accuracy and applicability of soil permeability measurement, so as to achieve permeability measurement of different moisture conditions and soil types. Summary of the invention

[0004] The purpose of the present invention is to provide a simple device for measuring soil permeability in multiple ranges in view of the deficiencies in the prior art. The present invention can quickly switch gas flow meters of different ranges according to the permeability of different soil samples, thereby realizing accurate measurement of different gas flow ranges. The whole device can measure soils with poor permeability such as high water content and heavy texture in low-range mode, thereby reducing measurement errors. The components are easy to assemble, low in cost, and independent of each other. All pipeline interface parts are pneumatic quick interfaces, which are easy to disassemble, reduce the maintenance cost of the device, and are easy to operate.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a simple device for measuring multi-range soil permeability, including a portable gas source, a switchable multi-range gas metering module, a differential pressure gauge and a sample base with a hollow structure; The gas supply port of the portable gas source is connected to the gas inlet port of the switchable multi-range gas metering module for providing gas; The gas outlet of the switchable multi-range gas metering module is connected to the interior of the sample base for measuring the gas flow rate; The top of the sample base is air permeable, and a soil ring knife sample is placed on the top of the sample base; The differential pressure gauge is connected to the interior of the sample base and is used to measure the pressure difference between the inside and outside of the system.

[0006] Based on the above, the portable gas source includes an air supply pump, which is connected to an external power supply and has its own power adjustment knob. The air supply port of the air supply pump is equipped with a pneumatic quick connector and is connected to the air inlet of the switchable multi-range gas metering module through a first air duct, and a gas flow rate regulating valve is provided on the first air duct.

[0007] Based on the above, the switching multi-range gas metering module includes several gas flow meters, and the range of each gas flow meter increases successively. The outlet of the first gas duct is connected in parallel with the air inlet of each gas flow meter respectively, and the outlet of each gas flow meter is connected in parallel and connected to the interior of the sample base through the second gas duct. Each gas flow meter is also provided with a valve for opening and closing the gas flow meter.

[0008] Based on the above, the switching multi-range gas metering module also includes a rotating shell, a metering base, an upper gas stabilization chamber and a lower gas stabilization chamber. The rotating shell is a cylindrical body that passes through from top to bottom. The bottom of the rotating shell is rotatably mounted on the metering base through a plane bearing. The upper gas stabilization chamber and the lower gas stabilization chamber are coaxially mounted at the upper and lower ends of the rotating shell respectively. A multi-body is installed at the top center of the upper gas stabilization chamber and the bottom center of the lower gas stabilization chamber. The outer circumference of the multi-body is provided with a plurality of gas channels arranged in a circumferential array and corresponding to each gas flow meter one by one. An externally threaded gas pipe joint is installed in the gas channel. The lower end of the upper multi-body is open and communicated with the interior of the upper gas stabilization chamber. The upper end of the lower multi-body is open and communicated with the interior of the lower gas stabilization chamber. The upper end of the upper multi-body and the lower end of the lower multi-body are both equipped with pneumatic rotating joints. The gas flow meters are arranged in a circular array and vertically fixed on the outer side of the rotating shell, the bottom air inlet of each gas flow meter is connected one by one with each externally threaded air pipe joint on the multi-pass body on the lower side through the fourth air guide pipe, and the top air outlet of each gas flow meter is connected one by one with each externally threaded air pipe joint on the multi-pass body on the upper side through the fifth air guide pipe. The upper end of the rotating shell is snap-connected with a top cover with a center hole, and the lower end of the rotating shell is snap-connected with a bottom cover with a center hole. The upper pneumatic rotary joint passes through the center hole of the top cover, and the air outlet of the upper pneumatic rotary joint is connected with the interior of the sample base through the second air guide pipe. The first air guide pipe passes through the bottom of the metering base, and the lower pneumatic rotary joint passes through the center hole of the bottom cover. The air inlet of the lower pneumatic rotary joint is connected with the pneumatic quick connector in the air supply port of the air supply pump through the first air guide pipe.

[0009] Based on the above, the sample base is a hollow cylinder, a breathable mesh is provided on the top of the sample base, a first pneumatic quick interface connected to the interior of the sample base is installed on the lower side of the side wall of the sample base, a second pneumatic quick interface connected to the interior of the sample base is installed on the bottom of the sample base, and both ends of the second air duct are respectively connected to the air outlet of the upper pneumatic rotary joint and the first pneumatic quick interface, and the second pneumatic quick interface is connected to the differential pressure gauge through the third air duct.

[0010] Based on the above, the differential pressure gauge is a digital differential pressure gauge, and the range of the differential pressure gauge is 0~1000pa.

[0011] Based on the above, it also includes a sample holder, which is a hollow holder. The height of the sample holder is flush with the height of the rotating shell. A plug hole is provided on the top of the sample holder, and a mounting hole is provided on the side of the sample holder. The sample base is fixed on the top of the sample holder. The second pneumatic quick interface passes through the plug hole accordingly, the differential pressure gauge is matched and embedded in the mounting hole, and the third air duct is placed inside the sample holder.

[0012] Based on the above, the rotating shell, top cover, bottom cover, metering base and sample support are all made of ABS material by 3D printing, and the sample base, upper gas stabilization chamber and lower gas stabilization chamber are all made of PVC material.

[0013] The present invention has outstanding substantive features and significant progress compared to the prior art. Specifically, the beneficial effects of the present invention are: 1) The switchable multi-range gas metering module of the present invention is a rotary design, which is composed of a plurality of gas flow meters of different ranges connected in parallel. It can quickly switch gas flow meters of different ranges according to the air permeability of different soil samples, thereby realizing accurate measurement of different gas flow ranges. The whole device can measure soils with poor air permeability such as high water content and heavy texture in low-range mode, thereby reducing measurement errors; 2) The components of the present invention are simple to assemble, low in cost, and independent of each other. All pipeline interface parts are pneumatic quick interfaces, which are easy to disassemble and can achieve rapid disassembly and replacement of faulty components, reduce device maintenance costs, and are easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structural connection of the present invention.

[0015] Figure 2 It is a structural explosion diagram of the switchable multi-range gas metering module of the present invention.

[0016] Figure 3 It is a structural schematic diagram of a sample base, a sample support and a differential pressure gauge of the present invention.

[0017] Figure 4 It is a fitting diagram of the air permeability and volumetric water content of the measured soil samples.

[0018] In the figure: 1. sample base; 2. differential pressure gauge; 3. air supply pump; 4. first air duct; 5. gas flow rate regulating valve; 6. gas flow meter; 7. second air duct; 8. rotating shell; 9. metering base; 10. upper gas stabilization chamber; 11. lower gas stabilization chamber; 12. plane bearing; 13. multi-body; 14. gas channel; 15. pneumatic rotary joint; 16. second pneumatic quick interface; 17. top cover; 18. bottom cover; 19. breathable mesh; 20. first pneumatic quick interface; 21. sample support; 22. plug hole; 23. mounting hole; 24. valve. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further described in detail below through specific implementation methods.

[0020] like Figures 1 to 4As shown, a simple device for measuring multi-range soil permeability includes a portable gas source, a switchable multi-range gas metering module, a differential pressure gauge 2 and a sample base 1 with a hollow structure; The gas supply port of the portable gas source is connected to the gas inlet port of the switchable multi-range gas metering module for providing gas; The gas outlet of the switchable multi-range gas metering module is connected to the interior of the sample base 1 for measuring the gas flow rate; The top of the sample base 1 is air permeable, and a soil ring knife sample (not shown) is placed on the top of the sample base 1; The differential pressure gauge 2 is connected to the interior of the sample base 1 and is used to measure the pressure difference between the inside and outside of the system.

[0021] In this embodiment, the portable gas source includes an air supply pump 3, which is connected to an external power supply (not shown), and has its own power adjustment knob. The air supply port of the air supply pump 3 is equipped with a pneumatic quick connector and is connected to the air inlet of the switchable multi-range gas metering module through a first air guide pipe 4. A gas flow rate regulating valve 5 is provided on the first air guide pipe 4. The power of the air supply pump 3 is 5w, the external power supply is a 220V power supply, and the maximum output air flow of the air supply pump 3 is 10L / min. The gas flux can be controlled by the gas flow rate regulating valve 5.

[0022] In this embodiment, the switchable multi-range gas metering module includes six gas flow meters 6, and the ranges of the six gas flow meters 6 increase successively. The gas outlets of the first air guide pipe 4 are respectively connected in parallel with the gas inlets of the gas flow meters 6, and the gas outlets of the gas flow meters 6 are connected in parallel and communicated with the interior of the sample base 1 through the second air guide pipe 7. Each gas flow meter 6 is also provided with a valve 24 for opening and closing the gas flow meter 6. The range of the gas flow meter 6 with the smallest range is 30 to 300 ml / min, and the range of the gas flow meter 6 with the largest range is 1-10 L / min. This makes the switchable multi-range gas metering module have six different ranges and a large measurement range.

[0023] In this embodiment, the switchable multi-range gas metering module also includes a rotating shell 8, a metering base 9, an upper gas stabilization chamber 10 and a lower gas stabilization chamber 11. The rotating shell 8 is a cylindrical body that passes through from top to bottom. The bottom of the rotating shell 8 is rotatably mounted on the metering base 9 through a plane bearing 12. The upper gas stabilization chamber 10 and the lower gas stabilization chamber 11 are coaxially mounted at the upper and lower ends of the rotating shell 8 respectively. The top center of the upper gas stabilization chamber 10 and the bottom center of the lower gas stabilization chamber 11 are both equipped with a multi-body 13. The outer circumference of the multi-body 13 is provided with six gas channels 14 arranged in a circumferential array and corresponding to each gas flow meter 6. An external threaded gas pipe joint (not shown) is installed in the gas channel 14. The lower end of the upper multi-body 13 is open and communicated with the interior of the upper gas stabilization chamber 10. The upper end of the lower multi-body 13 is open and communicated with the interior of the lower gas stabilization chamber 11. The upper end of the upper multi-body 13 and the lower end of the lower multi-body 13 are both equipped with a pneumatic rotary joint 15. The gas flow meters 6 are arranged in a circular array and are vertically fixedly installed on the outer surface of the rotating shell 8. The bottom air inlet of each gas flow meter 6 is connected to each external threaded air pipe joint on the lower multi-pass body 13 through a fourth air guide pipe (not shown in the figure), and the top air outlet of each gas flow meter 6 is connected to each external threaded air pipe joint on the upper multi-pass body 13 through a fifth air guide pipe (not shown in the figure). The upper end of the rotating shell 8 is snap-connected with a top cover 1 with a center hole. 7. The lower end of the rotating shell 8 is snap-connected with a bottom cover 18 with a center hole, the upper pneumatic rotary joint 15 passes through the center hole of the top cover 17, the air outlet of the upper pneumatic rotary joint 15 is connected with the interior of the sample base 1 through the second air guide tube 7, the first air guide tube 4 passes through the bottom of the metering base 9, the lower pneumatic rotary joint 15 passes through the center hole of the bottom cover 18, and the air inlet of the lower pneumatic rotary joint 15 is connected with the pneumatic quick connector in the air supply port of the air supply pump 3 through the first air guide tube 4.

[0024] Specifically, the upper gas stabilization chamber 10 and the lower gas stabilization chamber 11 are placed inside the rotating shell 8, which not only simplifies the device structure, but also plays a role in pressure buffering and airflow stabilization of the device; the rotating shell 8 can rotate freely on the metering base 9 through the plane bearing 12, and the setting of the pneumatic rotary joint 15 can make the first air duct 4 and the second air duct 7 independent of the rotating shell 8, and can more freely connect the air supply pump 3 and the sample base 1 in different orientations; six gas flow meters 6 are installed in a circular array on the rotating shell 8, and when measuring the ventilation volume of the soil sample, the gas flow meters 6 of different ranges can be quickly switched according to the permeability of different soil samples, so as to realize accurate measurement of different gas flow ranges, have strong adaptability, can reduce measurement errors, and can rotate the working gas flow meter 6 to the side for easy observation by the operator.

[0025] In this embodiment, the sample base 1 is a hollow cylinder, and a breathable mesh 19 is provided on the top of the sample base 1. A first pneumatic quick interface 20 communicating with the inside of the sample base 1 is installed on the lower side of the side wall of the sample base 1, and a second pneumatic quick interface 16 communicating with the inside of the sample base 1 is installed on the bottom of the sample base 1. The two ends of the second air guide tube 7 are respectively connected to the air outlet of the upper pneumatic rotary joint 15 and the first pneumatic quick interface 20, and the second pneumatic quick interface 16 is connected to the differential pressure gauge 2 through the third air guide tube. After measuring the air permeability of the soil sample, the sample base 1 can also be used for subsequent experiments such as measuring the water conductivity of the soil sample, thereby improving the experimental efficiency. Here, the diameter of the sample base 1 is 70 mm.

[0026] In this embodiment, the pressure differential gauge 2 is a digital pressure differential gauge, and the range of the pressure differential gauge 2 is 0 to 1000 Pa. The pressure differential gauge 2 can be used to read the pressure difference between the inside and outside of the device during the measurement process.

[0027] In order to make the overall structure more compact, in this embodiment, a sample holder 21 is also included. The sample holder 21 is a hollow holder. The height of the sample holder 21 is flush with the height of the rotating shell 8. A plug hole 22 is provided at the top of the sample holder 21. A mounting hole 23 is provided at the side of the sample holder 21. The sample base 1 is fixed at the top of the sample holder 21. The second pneumatic quick interface 16 passes through the plug hole 22. The differential pressure gauge 2 is matched and embedded in the mounting hole 23. The third air guide tube is placed inside the sample holder 21. By providing the sample holder 21, on the one hand, the third air guide tube can be placed inside the sample holder 21, and the differential pressure gauge 2 is matched and embedded in the mounting hole 23 at the side of the sample holder 21, thereby making the overall structure more compact; on the other hand, the height of the sample holder 21 is flush with the height of the rotating shell 8, ensuring that the first pneumatic quick interface 20 is close to the height of the pneumatic rotary joint 15 on the upper side, so that the second air guide tube 7 does not contact the rotating shell 8, and the rotating shell 8 rotates more smoothly.

[0028] In this embodiment, the rotating shell 8, the top cover 17, the bottom cover 18, the metering base 9 and the sample support 21 are all made of ABS material by 3D printing, and the sample base 1, the upper gas stabilization chamber 10, the lower gas stabilization chamber 11, the multi-body 13 and the pneumatic rotary joint 15 are all made of PVC material. ABS material has the characteristics of being strong, durable and easy to process, and plays a good supporting role in the device; PVC material has a low production cost compared to other materials, is easy to seal, and improves the overall sealing of the device.

[0029] All pipeline interfaces in the simple device for measuring multi-range soil permeability are pneumatic quick interfaces, which are easy to disassemble and can realize rapid disassembly and replacement of faulty parts, reduce the maintenance cost of the device, and are easy to operate.

[0030] The operation process and working principle of this embodiment are as follows: (1) Use a soil sample ring cutter with a diameter of 70 mm to prepare a soil sample ring cutter, place the soil sample ring cutter sample on the sample base 1, and seal the soil sample ring cutter and the sample base 1 with a latex sleeve; (2) Turn on the gas source switch, connect the gas pump 3 to the external power supply, and control the gas flux through the power adjustment knob and gas flow rate regulating valve 5 of the gas pump 3. The generated gas passes through the first gas pipe 4, the gas flow meter 6 and the second gas pipe 7 in turn to reach the sample base 1, and then the gas penetrates upward through the air permeable mesh 19 on the top of the sample base 1 and permeates the soil sample before being discharged. According to the air permeability of the soil sample, select a gas flow meter 6 with a suitable range to measure the gas flow. When the valve 24 at the bottom of the gas flow meter 6 is fully opened, adjust the gas flow rate regulating valve 5 so that the reading of the differential pressure meter 2 is stable at 100Pa, and record the value of the gas flow meter 6. When the gas flow rate of the soil sample reads low within the range of a certain gas flow meter 6, unscrew the valve 24 at the bottom of the gas flow meter 6 of a smaller range, and at the same time close the valves 24 at the bottom of the other five gas flow meters 6 of a larger range, then the float of the gas flow meter 6 of the appropriate range rises and stabilizes at the corresponding position, and the operator directly reads the scale value of the corresponding position of the float and records it to measure the gas flow rate; if it is necessary to expand the gas flux, directly adjust the gas flow rate regulating valve 5, and at the same time select a corresponding appropriate gas flow meter 6 of a larger range to measure the gas flow rate; (3) Substitute the measured gas flow and pressure difference of the soil sample into the following permeability formula: Where Ka is the air permeability of the soil sample (μm 2 ); V is the gas flow rate (cm 3 · s -1 ); L is the height of the soil sample (cm); N is the gas viscosity in poise (Pa·s); A is the cross-sectional area of ​​the soil sample (cm 2 ); P is the pressure difference (Pa); The air permeability of the soil sample can be calculated using the above formula.

[0031] The bulk density of the device was 1.3 g cm -3 and 1.65 g cm -3 The permeability test of soil samples was carried out at different volumetric water contents. The texture of the soil samples was clay loam. During the permeability test, the pressure difference of the soil samples was kept stable at 100Pa. The gas flow through the soil samples was recorded at different time periods to obtain the permeability of the soil samples. The permeability and volumetric water content of the soil samples were fitted to obtain the fitting graph of the permeability and volumetric water content of the soil samples, as shown in Figure 1. Figure 4As shown, the bulk density is 1.3 g cm -3 and 1.65 g cm -3 The soil samples actually measured the air permeability Ka and volumetric water content θ v The exponential function relationships are y=1099.30e -0.071x (r 2 =0.97) and y=51482.63e -0.50x (r 2 =0.97).

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A simple device for measuring soil permeability in multiple ranges, characterized by: It includes a portable gas source, a switchable multi-range gas metering module, a differential pressure gauge and a hollow structure sample base; The gas supply port of the portable gas source is connected to the gas inlet port of the switchable multi-range gas metering module for providing gas; The gas outlet of the switchable multi-range gas metering module is connected to the interior of the sample base. The switchable multi-range gas metering module quickly switches different ranges according to the air permeability of different soil samples to measure the gas flow rate. The top of the sample base is air permeable, and a soil ring knife sample is placed on the top of the sample base; The differential pressure gauge is connected to the interior of the sample base and is used to measure the pressure difference between the inside and outside of the system.

2. The simple device for measuring multi-range soil permeability according to claim 1, characterized in that: The portable gas source includes an air supply pump, which is connected to an external power supply and has its own power adjustment knob. The air supply port of the air supply pump is equipped with a pneumatic quick connector and is connected to the air inlet of the switchable multi-range gas metering module through a first air duct, and a gas flow rate regulating valve is provided on the first air duct.

3. The simple device for measuring multi-range soil permeability according to claim 2, characterized in that: The switching multi-range gas metering module includes several gas flow meters, and the range of each gas flow meter increases successively. The outlet of the first gas pipe is connected in parallel with the air inlet of each gas flow meter respectively, and the outlet of each gas flow meter is connected in parallel and connected to the interior of the sample base through the second gas pipe. Each gas flow meter is also provided with a valve for opening and closing the gas flow meter.

4. The simple device for measuring multi-range soil permeability according to claim 3 is characterized in that: The switchable multi-range gas metering module also includes a rotating shell, a metering base, an upper gas stabilization chamber and a lower gas stabilization chamber. The rotating shell is a cylindrical body that penetrates from top to bottom. The bottom of the rotating shell is rotatably mounted on the metering base through a plane bearing. The upper gas stabilization chamber and the lower gas stabilization chamber are coaxially mounted at the upper and lower ends of the rotating shell respectively. A multi-body is installed at the top center of the upper gas stabilization chamber and the bottom center of the lower gas stabilization chamber. The outer circumference of the multi-body is provided with a plurality of gas channels arranged in a circumferential array and corresponding to each gas flow meter one by one. An externally threaded gas pipe joint is installed in the gas channel. The lower end of the upper multi-body is open and communicated with the interior of the upper gas stabilization chamber. The upper end of the lower multi-body is open and communicated with the interior of the lower gas stabilization chamber. The upper end of the upper multi-body and the lower end of the lower multi-body are both equipped with pneumatic rotating joints. The flow meters are arranged in a circular array and vertically fixed on the outer side of the rotating shell, the bottom air inlet of each gas flow meter is connected one by one with each externally threaded air pipe joint on the lower multi-body through the fourth air guide pipe, and the top air outlet of each gas flow meter is connected one by one with each externally threaded air pipe joint on the upper multi-body through the fifth air guide pipe. The upper end of the rotating shell is snap-connected to the top cover with a center hole, and the lower end of the rotating shell is snap-connected to the bottom cover with a center hole. The upper pneumatic rotary joint passes through the center hole of the top cover, and the air outlet of the upper pneumatic rotary joint is connected to the inside of the sample base through the second air guide pipe. The first air guide pipe passes through the bottom of the metering base, and the lower pneumatic rotary joint passes through the center hole of the bottom cover. The air inlet of the lower pneumatic rotary joint is connected to the pneumatic quick connector in the air supply port of the air supply pump through the first air guide pipe.

5. The simple device for measuring multi-range soil permeability according to claim 4, characterized in that: The sample base is a hollow cylinder, and a breathable mesh is provided on the top of the sample base. A first pneumatic quick interface connected to the interior of the sample base is installed on the lower side of the side wall of the sample base, and a second pneumatic quick interface connected to the interior of the sample base is installed on the bottom of the sample base. Both ends of the second air guide tube are respectively connected to the air outlet of the upper pneumatic rotary joint and the first pneumatic quick interface, and the second pneumatic quick interface is connected to the differential pressure gauge through the third air guide tube.

6. The simple device for measuring multi-range soil permeability according to claim 1, characterized in that: The differential pressure gauge is a digital differential pressure gauge with a measuring range of 0 to 1000 Pa.

7. The simple device for measuring multi-range soil permeability according to claim 5, characterized in that: It also includes a sample holder, which is a hollow holder. The height of the sample holder is flush with the height of the rotating shell. A plug hole is provided on the top of the sample holder, and a mounting hole is provided on the side of the sample holder. The sample base is fixed on the top of the sample holder. The second pneumatic quick interface passes through the plug hole, the differential pressure gauge is matched and embedded in the mounting hole, and the third air duct is placed inside the sample holder.

8. The simple device for measuring multi-range soil permeability according to claim 7, characterized in that: The rotating shell, top cover, bottom cover, metering base and sample support are all made of ABS material by 3D printing, and the sample base, upper gas stabilization chamber and lower gas stabilization chamber are all made of PVC material.

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