Soil air pressure measuring device

Abstract

The embodiment of the utility model discloses a soil air pressure measuring device, which relates to the field of geotechnical engineering monitoring, and comprises a shell, a waterproof ventilation device and a pressure sensing device, the waterproof breathable device comprises an adapter, a first waterproof breathable film and a second waterproof breathable film; the pressure sensing device is arranged in the shell, and the shell is connected with the adapter; the adapter is provided with a first open hole, the first waterproof breathable film is arranged above the first open hole, and the second waterproof breathable film is arranged below the first open hole. According to the soil air pressure measuring device provided by the utility model, the double-layer waterproof breathable film is adopted, so that the air pressure of the soil with any water content can be accurately measured, the influence of water in the soil on the air pressure measurement can be effectively avoided, and the measurement error is reduced. Meanwhile, the size of the gas pressure sensing cavity can be autonomously controlled, the time for sensing the air pressure in the soil body by the sensor is shortened, and the effects of improving the sensitivity and the measurement accuracy are achieved.

Description

Technical Field

[0001] The utility model relates to the field of geotechnical engineering monitoring, in particular to a soil air pressure measuring device. Background Art

[0002] The air pressure in soil is an important parameter in many engineering applications, such as evaluating the effect of pore gas pressure on water infiltration in soil, optimizing the design of landfill extraction wells, and evaluating the performance of landfill cover layers in reducing landfill gas emissions. The accurate measurement of air pressure in soil is of great significance for the smooth implementation of these engineering applications. Existing geobarometers use a method of wrapping geotextiles at the front end of the pressure sensor or wrapping geotextiles at the end of the pressure measurement lead pipe for measurement. There is an air cavity between the geotextile and the pressure sensor cavity, but the air cavity space design of conventional pressure sensors is generally relatively fixed (the air cavity is relatively large or the lead pipe is very long), which is not easy to change.

[0003] Existing geobarometers have at least three defects:

[0004] First, the existing geobarometer can only measure the air pressure of soil with low water content, because when the water content in the soil increases, the water in the soil will enter the pressure-sensitive air cavity of the sensor through the geotextile under the action of pressure, and the geotextile cannot effectively block the water in the soil from entering the pressure-sensitive air cavity of the sensor, thereby increasing the error of air pressure measurement and even causing measurement distortion (because the measured data is no longer a simple air pressure, but a water-air mixed pressure);

[0005] Second, the existing geotechnical barometer pressure pipe is too long, which causes the pressure-sensitive air cavity in the pressure pipe to increase, reducing the sensitivity of air pressure measurement. When the air pressure in the soil is small, the pressure sensor pressure-sensitive diaphragm can basically not sense it under high water content conditions, which places high requirements on the pressure sensor itself and increases the measurement cost accordingly.

[0006] Third, the surface of the top cap at the front end of the existing geobarometer is flat, and the moisture in the soil can easily block the gas from entering the pressure-sensing air cavity, increasing the hysteresis of the pressure measurement. Utility Model Content

[0007] The technical problem to be solved by the embodiments of the utility model is that the geobarometer is insensitive to small air pressures because water in the soil with high water content easily enters the gas pressure sensing cavity and cannot achieve accurate measurement.

[0008] In order to solve the above problems, the embodiment of the utility model discloses a soil air pressure measuring device. The air pressure of soil with any moisture content can be accurately measured, shortening the time for the sensor to sense the air pressure in the soil, thereby achieving the effect of improving sensitivity and measurement accuracy.

[0009] The utility model provides a soil air pressure measuring device, which comprises a shell, a waterproof and breathable device and a pressure sensing device; the waterproof and breathable device comprises an adapter, a first waterproof and breathable membrane and a second waterproof and breathable membrane; the pressure sensing device is arranged in the shell, and the shell is connected to the adapter; the adapter is provided with a first opening, the first waterproof and breathable membrane is arranged above the first opening, and the second waterproof and breathable membrane is arranged below the first opening.

[0010] A further technical solution is that it also includes a top cap, which is arranged below the adapter. The top cap is provided with a water inlet hole, and the water inlet hole is connected to the first opening.

[0011] A further technical solution is that the top cap is also provided with a hemispherical groove, and the hemispherical groove is connected to the water inlet hole.

[0012] A further technical solution is that the outer surface of the top cap is provided with a hydrophobic coating.

[0013] A further technical solution is that the adapter is further provided with a first groove and a second groove, the first opening is respectively connected to the first groove and the second groove, the first waterproof breathable membrane is provided on the first groove, and the second waterproof breathable membrane is provided on the second groove.

[0014] A further technical solution is that it also includes a first fixing plate, the first fixing plate is arranged on the first groove, the first fixing plate is provided with a first air hole, and the first waterproof breathable membrane is respectively connected to the first air hole and the first opening.

[0015] A further technical solution is that it also includes a first sealing ring, which is respectively connected to the first waterproof and breathable membrane and the first fixing plate.

[0016] A further technical solution is that it also includes a second fixing plate, the second fixing plate is arranged on the second groove, the second fixing plate is provided with a second air hole, and the second waterproof breathable membrane is respectively connected to the second air hole and the first opening.

[0017] A further technical solution is that it also includes a second sealing ring, and the second sealing ring is respectively connected to the second waterproof and breathable membrane and the second fixing plate.

[0018] A further technical solution is that the adapter is further provided with a second opening, and the second opening is communicated with the first groove.

[0019] Compared with the prior art, the technical effects achieved by the embodiments of the present invention include:

[0020] A double-layer membrane structure is formed by the first waterproof breathable membrane and the second waterproof breathable membrane. The distance between the double-layer membranes is adjustable. The pressure sensing device, the shell, the first waterproof breathable membrane and the adapter enclose the sensor chamber to be filled with air-free water. The closed air-free water is incompressible because there are no bubbles in it, and the air pressure at the first waterproof breathable membrane can be quickly transmitted.

[0021] The distance between the first waterproof breathable membrane and the second waterproof breathable membrane is adjustable. For example, shortening the distance between the first waterproof breathable membrane and the second waterproof breathable membrane can compress the spatial volume of the device, shorten the time for the pressure sensing device to sense the air pressure in the soil, and improve the sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic diagram of the structure of a soil air pressure measuring device provided in an embodiment of the utility model;

[0024] Figure 2 A schematic diagram of the structure of another soil air pressure measuring device provided by an embodiment of the utility model;

[0025] Figure 3 A schematic diagram of a top cover structure provided by an embodiment of the utility model;

[0026] Figure 4 A schematic diagram of another top cover structure provided in an embodiment of the utility model.

[0027] Reference numerals

[0028] Shell 1, pressure sensing device 3, adapter 21, first waterproof breathable membrane 22, second waterproof breathable membrane 23, first opening 211, top cap 4, water inlet 41, hemispherical groove 42, first groove 212, second groove 213, first fixing plate 5, first air hole 51, first sealing ring 6, second fixing plate 7, second air hole 71, second sealing ring 8, second opening 214. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments. Similar component numbers in the drawings represent similar components. Obviously, the embodiments to be described below are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0030] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0031] It should also be understood that the terms used in this utility model embodiment specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model embodiments. As used in the utility model embodiment specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0032] See also Figure 1-4 The embodiment of the utility model provides a soil air pressure measuring device. The soil air pressure measuring device includes a housing 1, a waterproof and breathable device and a pressure sensing device 3; the waterproof and breathable device includes an adapter 21, a first waterproof and breathable membrane 22 and a second waterproof and breathable membrane 23; the pressure sensing device 3 is arranged in the housing 1, and the housing 1 is connected to the adapter 21; the adapter 21 is provided with a first opening 211, the first waterproof and breathable membrane 22 is arranged above the first opening 211, and the second waterproof and breathable membrane 23 is arranged below the first opening 211. The specific introduction of each component is as follows:

[0033] In this embodiment, the pressure sensing device 3 includes a pressure sensing diaphragm, and the pressure sensing device 3 is installed in the shell 1. The pressure sensing device 3, the shell 1, the first waterproof breathable membrane 22 and the adapter 21 enclose a sensor chamber, and the sensor chamber is filled with air-free water. The adapter 21 is connected to the shell 1 through threads. The first waterproof breathable membrane 22 is tightly fitted above the first opening 211, and the second waterproof breathable membrane 23 is tightly fitted below the first opening 211. The thickness of the first waterproof breathable membrane 22 ranges from 0.02 to 0.3 mm, which is used to seal the air-free water in the sensor chamber and sense the air pressure of the first opening 211 of the adapter 21; the thickness of the second waterproof breathable membrane 23 ranges from 0.02 to 0.3 mm, which is used to block the water of the water-gas mixture in the soil and only allow the gas of the water-gas mixture to pass through. In one embodiment, the distance between the first waterproof breathable membrane 22 and the second waterproof breathable membrane 23 is the length of the first opening 211 of the adapter 21. In a specific implementation, the distance between the first waterproof breathable membrane 22 and the second waterproof breathable membrane 23 can be shortened by shortening the length of the first opening 211, thereby reducing the spatial volume of the device, shortening the time for the sensor to sense the air pressure in the soil, and improving the sensitivity.

[0034] The working process of the soil air pressure measuring device is as follows:

[0035] The first waterproof breathable membrane is used to seal airless water, and the second waterproof breathable membrane is used to introduce air pressure and block water. The gas of the water-gas mixture generates air pressure on the first waterproof breathable membrane 22 through the first opening 211. The first waterproof breathable membrane 22 conducts the air pressure to the pressure sensing device 3 through the airless water to complete the air pressure measurement.

[0036] The technical effects that the soil air pressure measuring device can achieve are as follows:

[0037] A double-layer membrane structure is formed by the first waterproof breathable membrane 22 and the second waterproof breathable membrane 23. The distance between the double-layer membranes is adjustable. The pressure sensing device 3, the shell 1, the first waterproof breathable membrane 22 and the adapter 21 enclose the sensor chamber to be filled with air-free water. The closed air-free water is incompressible because there are no bubbles in it, and the air pressure at the first waterproof breathable membrane 22 can be quickly transmitted.

[0038] The distance between the first waterproof breathable membrane 22 and the second waterproof breathable membrane 23 is adjustable. For example, shortening the distance between the first waterproof breathable membrane 22 and the second waterproof breathable membrane 23 can compress the spatial volume of the device, shorten the time for the pressure sensing device 3 to sense the air pressure in the soil, and improve the sensitivity.

[0039] Continue to see Figure 1-4 In this embodiment, a top cap 4 is further included. The top cap 4 is arranged below the adapter 21 . The top cap 4 is provided with a water inlet hole 41 . The water inlet hole 41 is connected to the first opening 211 .

[0040] Specifically, the top cap 4 is detachably connected to the adapter 21 . In this embodiment, the top cap 4 is installed on the bottom of the adapter 21 through threads, and the water inlet holes 41 are aligned one by one with the first openings 211 .

[0041] Furthermore, the top cap 4 is also provided with a hemispherical groove 42 , and the hemispherical groove 42 is communicated with the water inlet hole 41 .

[0042] Specifically, a hemispherical groove 42 is provided at the bottom of the top cap 4. In one embodiment, the number of water inlet holes 41 is multiple, and the number of hemispherical grooves 42 is equal to the number of water inlet holes 41, and each hemispherical groove 42 is connected to the water inlet hole 41. After the water-gas mixture in the soil enters the hemispherical groove 42, since the density of the gas in the water-gas mixture is less than the density of water, the bubbles in the water will gather upward at the top of the hemispherical groove 42, and the gas of the water-gas mixture will quickly pass through the water inlet hole 41 and the second waterproof breathable membrane 23 in sequence, and enter the first opening 211. The water of the water-gas mixture will slowly fill the water inlet hole 41. The design of the hemispherical groove 42 can effectively separate the water-gas mixture. The top cap 4 is provided with a hemispherical groove 42 to form a dome shape, which prevents the front end surface of the adapter 21 from contacting the soil from being flat, so that the gas in the soil can more easily enter the first waterproof breathable membrane 22, reducing the hysteresis of the air pressure measurement.

[0043] Furthermore, the outer surface of the top cap 4 is provided with a hydrophobic coating.

[0044] Specifically, the outer surface of the top cap 4 is sprayed with a hydrophobic coating, and the outer surface of the top cap 4 is in contact with the soil. The hydrophobic coating is provided on the outer surface of the top cap 4 to eliminate the adsorption effect between water in the soil and the outer surface of the top cap 4. When the water in the soil no longer stays on the outer surface of the top cap 4, the gas in the soil can more easily break through the constraints of the water film under the action of the air pressure and enter the hemispherical groove 42, and the gas then quickly reaches the first waterproof breathable membrane 22.

[0045] Furthermore, the adapter 21 is also provided with a first groove 212 and a second groove 213 , the first opening 211 is connected to the first groove 212 and the second groove 213 respectively, the first waterproof breathable membrane 22 is provided on the first groove 212 , and the second waterproof breathable membrane 23 is provided on the second groove 213 .

[0046] Specifically, a first groove 212 is provided at the top of the adapter 21, a second groove 213 is provided at the bottom of the adapter 21, and grooves are provided at the upper and lower ends respectively. In this embodiment, the upper groove of the adapter 21 is the first groove 212, and the lower groove of the adapter 21 is the second groove 213, wherein a first waterproof and breathable membrane 22 is flatly laid in the first groove 212, and the thickness of the first waterproof and breathable membrane 22 is 0.02 to 0.3 mm, and a second waterproof and breathable membrane 23 is flatly laid in the second groove 213, and the thickness of the second waterproof and breathable membrane 23 is 0.02 to 0.3 mm. In one embodiment, the second waterproof and breathable membrane 23 and the first waterproof and breathable membrane 22 are made of the same material and size.

[0047] Furthermore, it also includes a first fixing plate 5, which is arranged on the first groove 212, and the first fixing plate 5 is provided with a first air hole 51, and the first waterproof breathable membrane 22 is respectively connected to the first air hole 51 and the first opening 211.

[0048] Specifically, the first fixing plate 5 is installed above the first waterproof breathable membrane 22, and the first air holes 51 are evenly distributed on the first fixing plate 5. The diameter of the first air holes 51 ranges from 0.5 to 2 mm. The positions of the first air holes 51 arranged on the first fixing plate 5 are the same as the positions of the first openings 211 arranged on the adapter 21. In one embodiment, the positions, number, and diameters of the first air holes 51 and the first openings 211 are respectively the same.

[0049] Furthermore, it also includes a first sealing ring 6, and the first sealing ring 6 is connected to the first waterproof and breathable membrane 22 and the first fixing plate 5 respectively.

[0050] Specifically, the first sealing ring 6 is an elastic sealing ring made of rubber. In this embodiment, the first sealing ring 6 is installed between the first fixing plate 5 and the first waterproof breathable membrane 22. The first fixing plate 5 is installed in the first groove 212 of the adapter 21 and squeezes the first sealing ring 6 in the first groove 212 to achieve a tight seal between the first waterproof breathable membrane 22 below the first sealing ring 6 and the bottom of the first groove 212.

[0051] Furthermore, it also includes a second fixing plate 7, which is arranged on the second groove 213, and the second fixing plate 7 is provided with a second air hole 71, and the second waterproof breathable membrane 23 is respectively connected to the second air hole 71 and the first opening 211.

[0052] Specifically, the second fixing plate 7 is installed below the second waterproof breathable membrane 23, and second air holes 71 are evenly distributed on the second fixing plate 7. The diameter of the second air holes 71 ranges from 0.5 to 2 mm. The positions of the second air holes 71 arranged on the second fixing plate 7 are the same as the positions of the first openings 211 arranged on the adapter 21. In one embodiment, the second air holes 71 are the same as the first openings 211 in position, number, and diameter.

[0053] Furthermore, it also includes a second sealing ring 8, and the second sealing ring 8 is connected to the second waterproof and breathable membrane 23 and the second fixing plate 7 respectively.

[0054] Specifically, the second sealing ring 8 is an elastic sealing ring made of rubber. In this embodiment, the second sealing ring 8 is installed between the second fixing plate 7 and the second waterproof breathable membrane 23. The second fixing plate 7 is installed in the second groove 213 of the adapter 21 and squeezes the second sealing ring 8 in the second groove 213 to achieve a tight seal between the second waterproof breathable membrane 23 above the second sealing ring 8 and the top of the second groove 213.

[0055] Furthermore, the adapter 21 is further provided with a second opening 214 , and the second opening 214 is communicated with the first groove 212 .

[0056] Specifically, a second opening 214 is provided on the upper side wall of the adapter 21, and the second opening 214 is connected to the first groove 212. In this embodiment, the diameter range of the second opening 214 is 2 to 4 mm. The second opening 214 includes a bolt hole, and the bolt can be screwed in / out of the second opening 214. The second opening 214 is used to replace the airless water in the closed cavity formed by the first groove 212 and the pressure sensing device 3.

[0057] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0058] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0059] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0060] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0062] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0063] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include these modifications and variations.

[0064] The above is a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A soil air pressure measuring device, characterized in that: It includes a shell, a waterproof and breathable device, and a pressure sensing device; The waterproof and breathable device comprises an adapter, a first waterproof and breathable membrane and a second waterproof and breathable membrane; The pressure sensing device is disposed in the housing, and the housing is connected to the adapter; The adapter is provided with a first opening, the first waterproof and breathable membrane is provided above the first opening, and the second waterproof and breathable membrane is provided below the first opening.

2. The soil air pressure measuring device according to claim 1, characterized in that: It also includes a top cap, which is arranged below the adapter. The top cap is provided with a water inlet hole, and the water inlet hole is connected to the first opening.

3. The soil air pressure measuring device according to claim 2, characterized in that: The top cap is also provided with a hemispherical groove, and the hemispherical groove is communicated with the water inlet hole.

4. The soil air pressure measuring device according to claim 3, characterized in that: The outer surface of the top cap is provided with a hydrophobic coating.

5. The soil air pressure measuring device according to claim 1, characterized in that: The adapter is further provided with a first groove and a second groove, the first opening is connected to the first groove and the second groove respectively, the first waterproof breathable membrane is provided on the first groove, and the second waterproof breathable membrane is provided on the second groove.

6. The soil air pressure measuring device according to claim 5, characterized in that: It also includes a first fixing plate, which is arranged on the first groove. The first fixing plate is provided with a first air hole, and the first waterproof breathable membrane is respectively connected to the first air hole and the first opening.

7. The soil air pressure measuring device according to claim 6, characterized in that: It also includes a first sealing ring, which is connected to the first waterproof and breathable membrane and the first fixing plate respectively.

8. The soil air pressure measuring device according to claim 5, characterized in that: It also includes a second fixing plate, which is arranged on the second groove, and the second fixing plate is provided with a second air hole, and the second waterproof breathable membrane is respectively connected to the second air hole and the first opening.

9. The soil air pressure measuring device according to claim 8, characterized in that: It also includes a second sealing ring, which is connected to the second waterproof and breathable membrane and the second fixing plate respectively.

10. The soil air pressure measuring device according to claim 5, characterized in that: The adapter is further provided with a second opening, and the second opening is communicated with the first groove.

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