Collecting device for soil free gas

Abstract

The utility model relates to a soil free gas collecting device, which comprises a telescopic loop bar component, a gas collecting cylinder, a piston rod, a gas collecting pipe, a gas collecting pipe, a gas collecting pipe, a gas collecting pipe, a gas collecting pipe, a gas collecting pipe and a gas collecting pipe, and is characterized in that the telescopic loop bar component comprises a gas collecting cylinder and a piston rod, the gas flow port of the gas collection cavity is suitable for being pre-buried in soil to be detected, the piston rod can enable the gas collection cavity to be in a negative pressure state through stretching movement, and when the gas collection cavity is in the negative pressure state, free gas in the soil can enter the gas collection cavity from the gas flow port; the limiting piece is connected between the piston rod and the gas collecting cylinder and used for limiting the relative position of the piston rod in the gas collecting cylinder when the gas collecting cavity is in the negative pressure state. According to the device, the piston rod can retract in the gas collection cylinder to reach an initial position so as to discharge gas in the gas collection cavity, so that interference of original non-soil free gas in the gas collection cavity is avoided, and the authenticity of collected and collected gas samples is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of ground gas collection, in particular to a gas collection device for free soil gas. Background Art

[0002] In recent years, with the continuous deepening of gas geochemical research in various fields, hydrocarbon gases represented by CH4, non-hydrocarbon gases represented by CO2, H2, H2S, etc., and rare inert gases represented by He in soil free gas have all received much attention. These indicator information can provide important scientific basis for research on resources, environment, disasters, etc.

[0003] In order to obtain accurate component information in soil free gas, it is necessary to collect soil free gas first. China Utility Model Patent (Grant Announcement No.: CN203534870U) discloses a geochemical geogas measurement sampling device, which includes a bracket, a collection cover, a sampler and an anti-pollution cup. The bracket is equipped with a collection cover, and the collection cover is equipped with an anti-pollution cup, and the collection cover is connected to the sampler. A chamber is formed under the sampler, and the free gas in the soil is collected through the flow exchange between the gas in the chamber and the soil free gas. Not only is the free gas collection speed slow and time-consuming, but the original gas in the chamber will interfere with or affect the collection and measurement of the collected free gas, and the authenticity and representativeness of the collected gas sample cannot be guaranteed. Utility Model Content

[0004] The utility model provides a soil free gas collection device, which is used to solve the problems of the prior art that the soil free gas collection speed is slow and the authenticity of the collected gas samples cannot be guaranteed.

[0005] The utility model provides a soil free gas collection device, comprising:

[0006] A telescopic sleeve rod assembly, comprising a gas collecting cylinder and a piston rod telescopically connected to the gas collecting cylinder, wherein the telescopic sleeve rod assembly has a gas collecting cavity suitable for collecting free gas in the soil, and the gas collecting cavity is defined by an end surface of the piston rod in the gas collecting cylinder and an inner wall of the gas collecting cylinder;

[0007] The air flow opening of the gas collecting chamber is suitable for being pre-buried in the soil to be detected, and the piston rod can be stretched to move the gas collecting chamber to be in a negative pressure state. When the gas collecting chamber is in a negative pressure state, free gas in the soil can enter the gas collecting chamber through the air flow opening; and further comprising:

[0008] A limiter is connected between the piston rod and the gas collecting cylinder, and is used to limit the relative position of the piston rod on the gas collecting cylinder when the gas collecting chamber is in a negative pressure state, so that the gas collecting chamber is maintained at a preset volume to collect free gas.

[0009] Optionally, the air flow opening of the air collecting cavity is arranged at the bottom of the air collecting cylinder, and at least a part of the lower part of the air collecting cylinder is suitable for being pre-buried in the soil to be detected, so that the air flow opening is located in the soil;

[0010] One end of the piston rod extends into the gas collecting cylinder from the top opening of the gas collecting cylinder, and the piston rod telescopically moves in the up and down directions.

[0011] Optionally, the gas collecting cylinder has a receiving cavity for receiving a piston rod, and the shape and size of the inner wall of the receiving cavity are adapted to the piston rod.

[0012] Furthermore, the upper and lower ends of the accommodating cavity have openings, and the air flow opening is formed by the lower end opening of the accommodating cavity;

[0013] One end of the piston rod extends into the upper opening of the accommodating chamber. When the piston rod telescopes in the up-and-down directions, the lower end surface of the piston rod can reach an initial position flush with the air flow port to discharge the gas in the gas collecting chamber. When the piston rod is located at the initial position, the air flow port can be pre-buried in the soil.

[0014] Optionally, the soil free gas collection device further comprises a gas extraction component connected to the gas collecting chamber, and the gas extraction component is used to extract the free gas collected in the gas collecting chamber.

[0015] Furthermore, the air extraction assembly comprises:

[0016] An air pipe, wherein an air inlet end of the air pipe is communicated with the air collecting cavity, and an air outlet end of the air pipe extends out of the air collecting cavity;

[0017] The plugging is used to seal the air outlet end of the air pipe.

[0018] Furthermore, the plug is made of rubber material, and the suction needle can pierce the rubber material plug to extract the free soil gas collected by the gas collecting cavity and diffused into the air pipe.

[0019] Optionally, the air extraction assembly further includes:

[0020] The valve is arranged on the trachea and is used to control the on-off of the trachea.

[0021] Optionally, the gas extraction assembly is provided in plurality, and the plurality of gas extraction assemblies are arranged at intervals along the circumference of the gas collecting cylinder.

[0022] Optionally, the limiting member is a positioning bolt, and the piston rod is provided with a positioning hole that can cooperate with the positioning bolt. One end of the positioning bolt is limited on the gas collecting cylinder, and the other end passes through the gas collecting cylinder and extends into the positioning hole on the positioning bolt to limit the relative position of the piston rod in the gas collecting cylinder.

[0023] Furthermore, the positioning holes are arranged in multiple groups, and the multiple groups of positioning holes are arranged at intervals along the length direction of the piston rod;

[0024] Each group of positioning holes includes at least two positioning holes arranged at intervals along the circumference of the piston rod.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] 1. The method of using the soil free gas collection device in the utility model is as follows:

[0027] The piston rod is retracted relative to the gas collecting cylinder to reduce the volume of the gas collecting chamber to the minimum preset volume, and the minimum preset volume is close to zero, so that the gas in the gas collecting chamber flows out from the air flow outlet. At this time, the piston rod is located in the initial position; the air flow outlet of the gas collecting chamber is pre-buried in the soil to be tested, and the piston rod is pulled to make the gas collecting chamber reach a negative pressure state. The relative position between the piston rod and the gas collecting cylinder is fixed by a limit piece to keep the volume of the gas collecting chamber unchanged. Since the gas collecting chamber is in a negative pressure state, the free gas in the soil can continuously enter the gas collecting chamber through the air flow outlet, thereby collecting the free gas in the soil.

[0028] The soil free gas collection device in this embodiment can exhaust the gas in the gas collection chamber by retracting the piston rod in the gas collection cylinder to the initial position, thereby avoiding the interference of the original non-soil free gas in the gas collection chamber, ensuring the authenticity of the collected gas sample, and thus improving the accuracy and reliability of the detection data. In addition, after the air flow port is pre-buried in the soil, by pulling the piston rod, the volume of the gas collection chamber can be increased and the gas collection chamber can form a negative pressure state, so that the soil free gas can be quickly collected, and the device is easy to operate.

[0029] 2. In the utility model, since the piston rod is in the initial position, one end face of the piston rod in the gas collecting cylinder is flush with the lower opening of the accommodating chamber (i.e., the air flow outlet), so the original gas in the gas collecting cylinder can be completely discharged, making the volume of the gas collecting chamber close to zero.

[0030] 3. In the utility model, a handle is installed on one end of the piston rod outside the gas collecting cylinder, and the piston can be moved up and down manually or with the help of external mechanical transmission force, which is convenient for manipulating the piston rod to move up and down. In the case of mechanical transmission, a controller can also be connected to ensure that the movement speed of the piston rod is controllable.

[0031] 4. During use of the soil free gas collection device of the utility model, the gas collecting chamber under negative pressure continuously collects soil free gas. When the gas collecting chamber reaches a balanced state, the negative pressure gas collection stage is completed. At this time, the vacuum needle can be used to pierce the seal of the rubber material to extract the collected free gas.

[0032] 5. By inserting the positioning bolts into positioning holes at different heights, the piston rod can be restricted to different heights. The height of the piston rod relative to the gas collecting cylinder is proportional to the volume of the gas collecting chamber, so the gas collecting chamber can achieve the purpose of different gas collecting volumes. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings.

[0034] Figure 1 It is a schematic diagram of the structure of a collection device for free soil gas;

[0035] Figure 2 yes Figure 1 AA cross-sectional schematic diagram of the collection device for free gas in the soil.

[0036] Reference numerals:

[0037] 1. Gas collecting cylinder;

[0038] 2. Piston rod; 21. Positioning hole;

[0039] 3. Gas collecting cavity; 31. Air flow outlet;

[0040] 4. Positioning bolt;

[0041] 5. Air extraction assembly; 51. Air pipe; 52. Blockage; 53. Valve.

[0042] 6. Handle. DETAILED DESCRIPTION

[0043] The utility model will be further described below in conjunction with the accompanying drawings.

[0044] Embodiment 1

[0045] The present embodiment provides a soil free gas collection device, which includes a telescopic sleeve rod assembly and a limiter.

[0046] Specifically, the telescopic sleeve rod assembly includes a gas collecting cylinder 1 and a piston rod 2 telescopically connected to the gas collecting cylinder 1. The telescopic sleeve rod assembly has a gas collecting chamber 3 suitable for collecting free gas in the soil, and the gas collecting chamber 3 is defined by the end surface of the piston rod 2 in the gas collecting cylinder 1 and the inner wall of the gas collecting cylinder 1; the gas flow opening 31 of the gas collecting chamber 3 is suitable for being pre-buried in the soil to be detected, and the piston rod 2 can be stretched to move the gas collecting chamber 3 to be in a negative pressure state. When the gas collecting chamber 3 is in a negative pressure state, the free gas in the soil can enter the gas collecting chamber 3 through the gas flow opening 31.

[0047] The limiter is connected between the piston rod 2 and the gas collecting cylinder 1, and is used to limit the relative position of the piston rod 2 on the gas collecting cylinder 1 when the gas collecting chamber 3 is in a negative pressure state, so that the gas collecting chamber 3 is kept at a preset volume to collect free gas.

[0048] The method of using the soil free gas collection device in this embodiment is as follows:

[0049] Retract the piston rod 2 relative to the gas collecting cylinder 1 to reduce the volume of the gas collecting chamber 3 to the minimum preset volume, and the minimum preset volume is close to zero, so that the gas in the gas collecting chamber 3 flows out from the air flow outlet 31, and the piston rod 2 is in the initial position at this time; the air flow outlet 31 of the gas collecting chamber 3 is pre-buried in the soil to be tested, and the piston rod 2 is pulled to make the gas collecting chamber 3 reach a negative pressure state, and the relative position between the piston rod 2 and the gas collecting cylinder 1 is fixed by a limiter to keep the volume of the gas collecting chamber 3 unchanged. Since the gas collecting chamber 3 is in a negative pressure state, the free gas in the soil can continuously enter the gas collecting chamber 3 through the air flow outlet 31, so that the free gas in the soil can be collected.

[0050] The soil free gas collection device in this embodiment can exhaust the gas in the gas collection chamber 3 by retracting the piston rod 2 in the gas collection cylinder 1 to the initial position, thereby avoiding the interference of the original non-soil free gas in the gas collection chamber 3, ensuring the authenticity of the collected gas sample, and thus improving the accuracy and reliability of the detection data. In addition, after the air flow port 31 is pre-buried in the soil, by pulling the piston rod 2, the volume of the gas collection chamber 3 can be increased and the gas collection chamber 3 can form a negative pressure state, so that the soil free gas can be quickly collected, and the device is easy to operate.

[0051] The soil free gas collection device in this embodiment can be connected to on-site detection equipment such as gas sensors, and is suitable for large-volume collection and collection of near-surface soil free gas and on-site in-situ online detection in various research fields of gas geochemistry.

[0052] In the embodiment of the utility model, the air flow outlet 31 of the air collecting chamber 3 is arranged at the bottom of the air collecting cylinder 1, and at least a part of the lower part of the air collecting cylinder 1 is suitable for being pre-buried in the soil to be detected, so that the air flow outlet 31 is located in the soil; one end of the piston rod 2 extends into the air collecting cylinder 1 from the top opening of the air collecting cylinder 1, and the piston rod 2 telescopes in the up and down directions.

[0053] In this embodiment, the gas collecting cylinder 1 is a bottomless cylinder, and the gas collecting cylinder 1 has a accommodating chamber for placing the piston rod 2. The shape and size of the inner wall of the accommodating chamber are adapted to the piston rod 2. The piston rod 2 and the inner wall of the accommodating chamber are sealed to prevent the gas collecting chamber 3 from overflowing from the matching connection between the piston rod 2 and the gas collecting cylinder 1, thereby ensuring the air tightness requirements.

[0054] In this embodiment, the upper and lower ends of the accommodating chamber have openings, and the airflow port 31 is formed by the lower end opening of the accommodating chamber; one end of the piston rod 2 extends into the upper end opening of the accommodating chamber, and when the piston rod 2 moves in the up and down directions, the lower end surface of the piston rod 2 can reach the initial position flush with the airflow port 31 to discharge the gas in the gas collecting chamber 3; when the piston rod 2 is in the initial position, the airflow port 31 can be pre-buried in the soil. Since the piston rod 2 is in the initial position, one end surface of the piston rod 2 in the gas collecting cylinder 1 is flush with the lower end opening of the accommodating chamber (i.e., the airflow port 31), so the original gas in the gas collecting cylinder 1 can be completely discharged, so that the volume of the gas collecting chamber 3 is close to zero.

[0055] In this embodiment, a handle 6 is installed on one end of the piston rod 2 outside the gas collecting cylinder 1, and the piston can be moved up and down manually or with the help of external mechanical transmission force, which is convenient for manipulating the piston rod 2 to move up and down. A controller can also be connected during mechanical transmission to ensure that the movement speed of the piston rod 2 is controllable.

[0056] Embodiment 2

[0057] In this embodiment, the soil free gas collection device further includes a gas extraction component 5 connected to the gas collecting chamber 3 , and the gas extraction component 5 is used to extract the free gas collected in the gas collecting chamber 3 .

[0058] In this embodiment, the gas extraction assembly 5 includes an air pipe 51, a plug 52 disposed at the air outlet of the air pipe 51, and a valve 53 disposed on the air pipe 51 for controlling the on-off of the air pipe 51. Optionally, the gas extraction assembly 5 is provided in plurality, and the plurality of gas extraction assemblies 5 are arranged at intervals along the circumference of the gas collecting cylinder 1.

[0059] Specifically, the air inlet end of the air pipe 51 is connected to the gas collecting chamber 3, and the air outlet end of the air pipe 51 extends out of the gas collecting chamber 3. The air pipe 51 is installed on the gas collecting cylinder 1, and one end of the air inlet on the air pipe 51 extends from the inner wall of the bottom of the gas collecting cylinder 1 into the gas collecting chamber 3, and the installation connection between the air inlet end of the air pipe 51 and the gas collecting cylinder 1 is sealed; one end of the air outlet on the air pipe 51 is installed on the top or side wall of the gas collecting cylinder 1, and the installation connection between the air outlet end of the air pipe 51 and the gas collecting cylinder 1 is sealed.

[0060] Optionally, an internal thread is provided on the gas outlet at the upper end of the air pipe 51, and an external thread is provided on the outer wall of the plug 52 to cooperate with the gas outlet of the air pipe 51, and the plug 52 is used to seal the gas outlet of the air pipe 51. Optionally, the plug 52 is made of rubber material, and the suction needle can pierce the rubber plug 52 to extract the soil free gas collected by the gas collecting chamber 3 and diffused into the air pipe 51.

[0061] During use, the gas collecting chamber 3 under negative pressure continuously collects free gas in the soil. When the gas collecting chamber 3 reaches a balanced state, the negative pressure gas collecting stage is completed. At this time, the gas extraction needle can be used to pierce the rubber material plug 52 to extract the collected free gas. Of course, the valve 53 can be closed, the plug 52 can be unscrewed, and the gas collection pipe 51 or gas collection container can be connected to the gas outlet of the gas pipe 51, or the gas detection equipment can be directly connected.

[0062] Optionally, a pressure sensor is provided on the air pipe 51 to monitor whether the air in the air pipe 51 and the gas collecting chamber 3 has reached a balanced state. Of course, the limiter can also be removed, and if the piston rod 2 no longer moves freely downward by a large margin, the balance is reached.

[0063] Embodiment 3

[0064] The soil free gas collection device in this embodiment is basically the same as that in Embodiment 1 and Embodiment 2, with the difference that the limiting member in this embodiment is a positioning bolt 4, and a positioning hole 21 which can cooperate with the positioning bolt 4 is provided on the piston rod 2. One end of the positioning bolt 4 is limited on the gas collecting cylinder 1, and the other end passes through the gas collecting cylinder 1 and extends into the positioning hole 21 on the positioning bolt 4, so as to limit the relative position of the piston rod 2 in the gas collecting cylinder 1.

[0065] Optionally, the positioning holes 21 are arranged in multiple groups, and the multiple groups of positioning holes 21 are arranged at intervals along the length direction of the piston rod 2 ; each group of positioning holes 21 includes at least two positioning holes 21 arranged at intervals along the circumference of the piston rod 2 .

[0066] With such arrangement, the piston rod 2 can be restricted at different heights by inserting the positioning bolt 4 into the positioning holes 21 at different heights, and the height of the piston rod 2 relative to the gas collecting cylinder 1 is proportional to the volume of the gas collecting chamber 3, thereby enabling the gas collecting chamber 3 to achieve the purpose of different gas collecting volumes.

[0067] Embodiment 4

[0068] This embodiment provides a method for using a soil free gas collection device, and the specific operations are as follows:

[0069] Step 1: Adjust the piston rod 2 to the initial position so that one end surface of the piston rod 2 in the gas collecting cylinder 1 is flush with the lower end opening of the accommodating cavity on the gas collecting cylinder 1 (i.e., the air flow opening 31);

[0070] Step 2: dig a pit in the soil to be tested to a specified depth, bury the main body of the gas collecting cylinder 1 more than half of its height in the soil, and fill it with backfill soil around it to isolate it from atmospheric interference;

[0071] Step 3: After closing the valve 53 and tightening the plug 52, lift the handle 6 to slowly move the piston rod 2 upward, and the volume of the gas collecting chamber 3 gradually increases, so that the inside of the gas collecting chamber 3 is in a negative pressure state; when the gas collecting chamber 3 reaches the preset volume, insert the positioning bolt 4 into the positioning hole 21 for positioning;

[0072] Step 4: After the pressure in the gas collecting chamber 3 is balanced and the gas collecting stage is completed, a gas sample can be collected at the gas outlet of the gas pipe 51 .

[0073] When performing large-volume sampling, the valve 53 can be closed and the piston rod 2 can be moved upward to collect gas; after balancing, the piston rod 2 moves downward, the valve 53 is opened, and gas collection begins; the above operation is repeated to achieve the purpose of large-volume sampling.

[0074] Generally, when a large volume is collected, the small amount of residual gas in the trachea 51 accounts for a small proportion and the impact caused can be ignored, so there is no need to evacuate the trachea 51. However, if necessary, after step 2 and before step 3, a vacuum pump can be used to drain the residual gas in the trachea 51 to completely eliminate the dead volume effect.

[0075] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A soil free gas collection device, characterized in that: include: A telescopic sleeve rod assembly, comprising a gas collecting cylinder and a piston rod telescopically connected to the gas collecting cylinder, wherein the telescopic sleeve rod assembly has a gas collecting cavity suitable for collecting free gas in the soil, and the gas collecting cavity is defined by an end surface of the piston rod in the gas collecting cylinder and an inner wall of the gas collecting cylinder; The air flow opening of the gas collecting chamber is suitable for being pre-buried in the soil to be detected, and the piston rod can be stretched to move the gas collecting chamber to be in a negative pressure state. When the gas collecting chamber is in a negative pressure state, free gas in the soil can enter the gas collecting chamber through the air flow opening; and further comprising: A limiter is connected between the piston rod and the gas collecting cylinder, and is used to limit the relative position of the piston rod on the gas collecting cylinder when the gas collecting chamber is in a negative pressure state, so that the gas collecting chamber is maintained at a preset volume to collect free gas.

2. The soil free gas collection device according to claim 1, characterized in that: The air flow opening of the air collecting cavity is arranged at the bottom of the air collecting cylinder, and at least a part of the lower part of the air collecting cylinder is suitable for being pre-buried in the soil to be detected, so that the air flow opening is located in the soil; One end of the piston rod extends into the gas collecting cylinder from the top opening of the gas collecting cylinder, and the piston rod telescopically moves in the up and down directions.

3. The soil free gas collection device according to claim 1 or 2, characterized in that: The gas collecting cylinder has a receiving cavity for receiving a piston rod, and the shape and size of the inner wall of the receiving cavity are adapted to the piston rod.

4. The soil free gas collection device according to claim 3, characterized in that: The upper and lower ends of the accommodating cavity have openings, and the air flow opening is formed by the lower end opening of the accommodating cavity; One end of the piston rod extends into the upper opening of the accommodating chamber. When the piston rod telescopes in the up-and-down directions, the lower end surface of the piston rod can reach an initial position flush with the air flow port to discharge the gas in the gas collecting chamber. When the piston rod is located at the initial position, the air flow port can be pre-buried in the soil.

5. The soil free gas collection device according to claim 1, characterized in that: It also includes a gas extraction component connected to the gas collecting chamber, and the gas extraction component is used to extract the free gas collected in the gas collecting chamber.

6. The soil free gas collection device according to claim 5, characterized in that: The air extraction assembly comprises: An air pipe, wherein an air inlet end of the air pipe is communicated with the air collecting cavity, and an air outlet end of the air pipe extends out of the air collecting cavity; The plugging is used to seal the air outlet end of the air pipe.

7. The soil free gas collection device according to claim 6, characterized in that: The plug is made of rubber material, and the suction needle can pierce the rubber plug to extract the free soil gas collected by the gas collecting cavity and diffused into the air pipe.

8. The soil free gas collection device according to claim 6, characterized in that: The air extraction assembly also includes: The valve is arranged on the trachea and is used to control the on-off of the trachea.

9. The soil free gas collection device according to any one of claims 6 to 8, characterized in that: The gas extraction components are provided in plurality, and the plurality of gas extraction components are arranged at intervals along the circumference of the gas collecting cylinder.

10. The soil free gas collection device according to claim 1, characterized in that: The limiting member is a positioning bolt, and the piston rod is provided with a positioning hole that can cooperate with the positioning bolt. One end of the positioning bolt is limited on the gas collecting cylinder, and the other end passes through the gas collecting cylinder and extends into the positioning hole on the positioning bolt to limit the relative position of the piston rod in the gas collecting cylinder.

11. The soil free gas collection device according to claim 10, characterized in that: The positioning holes are arranged in multiple groups, and the multiple groups of positioning holes are arranged at intervals along the length direction of the piston rod; Each group of positioning holes includes at least two positioning holes arranged at intervals along the circumference of the piston rod.

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