CN220490501U - Soil gas monitoring sampling equipment - Google Patents
Soil gas monitoring sampling equipment Download PDFInfo
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- CN220490501U CN220490501U CN202321974104.3U CN202321974104U CN220490501U CN 220490501 U CN220490501 U CN 220490501U CN 202321974104 U CN202321974104 U CN 202321974104U CN 220490501 U CN220490501 U CN 220490501U
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- 238000005070 sampling Methods 0.000 title claims abstract description 173
- 239000002680 soil gas Substances 0.000 title claims abstract description 107
- 238000012544 monitoring process Methods 0.000 title claims abstract description 91
- 239000007789 gas Substances 0.000 claims abstract description 93
- 239000002689 soil Substances 0.000 claims abstract description 16
- 230000001360 synchronised effect Effects 0.000 abstract description 5
- 230000010354 integration Effects 0.000 abstract description 3
- 238000012360 testing method Methods 0.000 description 31
- 239000000700 radioactive tracer Substances 0.000 description 18
- 238000000034 method Methods 0.000 description 11
- 238000004458 analytical method Methods 0.000 description 10
- 239000001307 helium Substances 0.000 description 9
- 229910052734 helium Inorganic materials 0.000 description 9
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 9
- 239000003463 adsorbent Substances 0.000 description 8
- 238000001514 detection method Methods 0.000 description 8
- 238000000605 extraction Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 229910001220 stainless steel Inorganic materials 0.000 description 4
- 239000010935 stainless steel Substances 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 238000004891 communication Methods 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000011010 flushing procedure Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 230000035699 permeability Effects 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 239000003292 glue Substances 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- 239000012855 volatile organic compound Substances 0.000 description 2
- 239000002390 adhesive tape Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000005067 remediation Methods 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 230000000241 respiratory effect Effects 0.000 description 1
- 238000012502 risk assessment Methods 0.000 description 1
- 238000003900 soil pollution Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
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Abstract
The utility model discloses a soil gas monitoring sampling device, comprising: the gas collecting hood is provided with a first port, a second port and a third port; the system comprises at least one group of sampling systems, wherein any group of sampling systems comprises a valve I, a plurality of valves II, a valve III, an electronic flowmeter, an electronic negative pressure meter, a main conduit and a plurality of first branch conduits, and one valve II is arranged on one first branch conduit; the valve I, the electronic flowmeter, the electronic negative pressure meter and the valve III are sequentially connected through a main conduit, and the two first branch conduits are respectively communicated with a part of the main conduit, which is positioned between the electronic negative pressure meter and the valve III; when the air tightness of the soil air monitoring well is verified, the well pipe of the soil air monitoring well penetrates through the port and is selectively connected with one valve I. The utility model can detect the air tightness of the monitoring well and the sampling device, can meet the synchronous sampling of parallel samples, simultaneously samples a plurality of air paths, and has high integration degree and high sampling efficiency.
Description
Technical Field
The utility model relates to the technical field of soil gas monitoring. More particularly, the present utility model relates to soil gas monitoring sampling apparatus.
Background
The ministry of ecological environment issued "letter of opinion" about solicitation of guidelines (trials) for construction land soil pollution remediation target value (solicitation of opinion manuscripts) "5 months in 2022. The trial file is formally released in the same year for 12 months. In the guideline, a determination method such as soil gas, volatilization flux, human body availability and the like is proposed for setting a target value for repairing a volatile organic compound contaminated site. The soil gas monitoring method has the advantages that the soil gas monitoring is related to the soil gas monitoring, the related technical specifications and monitoring standards are not yet exported in China, and no formed equipment is put into production in the soil gas sampling process.
Besides being taken as a formulation basis of a repair target, the soil gas monitoring also provides a powerful support for various works such as site investigation, hidden trouble investigation, risk assessment and the like. Compared with the traditional soil monitoring, the soil gas can more intuitively reflect the migration and distribution of volatile pollutants in the ground, and has unique advantages for the pollutant formation mechanism, change rule and respiratory exposure management and control aspects. In addition, the soil gas monitoring well can be used for a long time after being constructed, so that the cost is saved in the aspect of conventional monitoring, and the emergency monitoring is more convenient.
Soil gas monitoring in China is in a starting development stage, still faces more difficulties and challenges, such as gas tightness detection of a monitoring well and a sampling device, synchronous sampling of parallel samples, simultaneous sampling of multiple gas paths, and low integration and sampling efficiency.
Disclosure of Invention
The utility model aims to provide soil gas monitoring and sampling equipment which can detect the air tightness of a monitoring well and a sampling device, can meet the synchronous sampling of parallel samples and simultaneous sampling of multiple gas paths, and has high integration degree and high sampling efficiency.
To achieve these objects and other advantages and in accordance with the purpose of the utility model, there is provided a soil gas monitoring and sampling apparatus comprising:
the gas collecting hood is provided with a first port, a second port and a third port;
the system comprises at least one group of sampling systems, wherein any group of sampling systems comprises a valve I, a plurality of valves II, a valve III, an electronic flowmeter, an electronic negative pressure meter, a main conduit and a plurality of first branch conduits, and one valve II is arranged on one first branch conduit; the valve I, the electronic flowmeter, the electronic negative pressure meter and the valve III are sequentially connected through a main conduit, and the two first branch conduits are respectively communicated with a part of the main conduit, which is positioned between the electronic negative pressure meter and the valve III; when the air tightness of the soil air monitoring well is verified, a well pipe in the soil air monitoring well penetrates through the port and is selectively connected with one valve I.
Preferably, in the soil gas monitoring and sampling device, the gas collecting hood is a cylinder with a hollow inside and one open bottom surface.
Preferably, in the soil gas monitoring and sampling device, the first port and the second port are both arranged on the side wall of the gas collecting hood, and the third port is arranged on the other bottom surface of the gas collecting hood.
Preferably, in the soil gas monitoring and sampling device, the first port and the second port are located at two sides of the side wall of the gas collecting hood.
Preferably, in the soil gas monitoring and sampling device, the sampling system has two groups.
Preferably, in the soil gas monitoring and sampling device, any one group of sampling systems further includes:
the second branch conduit is communicated with a part of the main conduit, which is positioned between the electronic flowmeter and the electronic negative pressure meter, and is provided with a knob valve;
and the PID tester is connected with the main pipe through the second branch pipe.
Preferably, in the soil gas monitoring and sampling device, the knob valve is located between the PID tester and the main pipe.
Preferably, in the soil gas monitoring and sampling device, the inner diameter of the gas collecting hood is 30cm.
Preferably, in the soil gas monitoring and sampling device, two valves are provided.
Preferably, in the soil gas monitoring and sampling device, the main pipe is connected with a vacuum pump/air pump, and the valve III is located between the vacuum pump/air pump and the valve I.
The utility model at least comprises the following beneficial effects:
the gas collecting hood can complete the gas tightness test of soil gas monitoring wells with different diameters, the diameters of which are smaller than 30cm.
The utility model can carry out the test work of the air tightness of the soil gas monitoring well and the air tightness of the soil gas sampling system.
The utility model adopts the electronic flowmeter and the electronic negative pressure meter, has higher precision and visual reading.
The valve III is arranged at the tail end of the sampling system, so that the flow direction of soil gas can be controlled, and the sampling device can be used for sampling containers in different modes, including a Suma tank, an adsorbent tube, an air bag sampling box and the like. The single passage is provided with a plurality of second valves, so that synchronous sampling of parallel samples can be met. The double channels are integrated, so that simultaneous sampling of two gas paths with different depths in the same well can be simultaneously met.
The utility model uses the test result of the PID tester to make preliminary judgment on the concentration of the soil gas before sampling so as to select proper sampling consumable or sampling volume.
The utility model is convenient to carry and can meet the requirements of site sampling and transferring and the like. The integrated level is high, the requirements of the standard on steps of building a well, equipment air tightness, sample collection and the like can be met, the material selection requirement is high, the stability of a sampling system can be ensured, and the air tightness is good.
Additional advantages, objects, and features of the utility model will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the utility model.
Drawings
FIG. 1 is a schematic diagram of a soil gas monitoring sampling apparatus according to one embodiment of the present utility model;
FIG. 2 is a schematic diagram of a sampling system according to one embodiment of the present utility model;
fig. 3 is a schematic diagram of a connection structure of a sampling system according to an embodiment of the present utility model.
Detailed Description
The present utility model is described in further detail below with reference to the drawings to enable those skilled in the art to practice the utility model by referring to the description.
It should be noted that, in the description of the present utility model, the terms "transverse", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model.
As shown in fig. 1 to 3, the present utility model provides a soil gas monitoring sampling apparatus comprising:
the gas collecting hood 1 is provided with a first port 101, a second port 102 and a third port 103; and a first port 101 is used for accessing an air duct in the soil gas monitoring well and is connected with the sampling system 2. The first port 101 is connected with the sampling system 2 for use, and gas in the soil gas monitoring well is extracted to evaluate the gas tightness of the soil gas monitoring well. And a second port 102 is used for testing the trace gas in the gas collecting hood 1 so as to meet the concentration requirement when the tightness of the soil gas well is evaluated. Port three 103 is used to release the trace gas.
At least one group of sampling systems 2, wherein any group of sampling systems 2 comprises a first valve 201, a plurality of second valves 202, a third valve 203, an electronic flowmeter 204, an electronic negative pressure meter 205, a main pipe 206 and a plurality of first branch pipes 207, and the second valve is arranged on one first branch pipe 207; the valve I201, the electronic flowmeter 204, the electronic negative pressure meter 205 and the valve III 203 are sequentially connected through a main conduit 206, and two first branch conduits 207 are respectively communicated with a part of the main conduit 206 between the electronic negative pressure meter 205 and the valve III 203; when verifying the tightness of the soil gas monitor well, a well pipe in the soil gas monitor well passes through the port one 101 and is selectively connected with one of the valve one 201.
The sampling system 2 is formed by assembling a series of metal pipes, a clamping sleeve connector, an electronic flowmeter 204, an electronic negative pressure meter 205 and a plurality of valves (a first valve 201, a plurality of second valves and a third valve 203), and the components are connected by adopting a stainless steel or copper clamping sleeve connector connection mode, so that the air tightness requirement can be met. Meanwhile, a series of metal pipes, a clamping sleeve connector, an electronic flowmeter 204, an electronic negative pressure meter 205 and a plurality of valves (a first valve 201, a plurality of second valves and a third valve 203) are all connected by stainless steel pipes, and the collected soil gas sample test cannot be interfered in the collection process. The electronic flowmeter 204 and the electronic negative pressure meter 205 are adopted, so that the accuracy is higher, the reading is visual, and the field working efficiency and accuracy can be improved. The valves (valve one 201, valve two and valve three 203) can control the flow direction of soil gas, and can be used for sampling containers in different modes, including a Suma tank, an adsorbent tube, an air bag sampling box and the like. The single passage is provided with a plurality of second valves, so that synchronous sampling of parallel samples can be met. The multiple channels are integrated, so that simultaneous sampling of multiple air channels can be simultaneously met.
The sampling system 2 is assembled by a series of metal pipes, a clamping sleeve connector, an electronic flowmeter 204, an electronic negative pressure meter 205 and a plurality of valves, the core function of the sampling system 2 is in the tightness, and the tightness of the assembly among all the components is ensured in one hundred percent. Meanwhile, since the sampling system 2 is used for collecting soil gas for testing volatile organic compounds, the assembly of the components cannot use any glue, adhesive tape, sealing ring or other substances possibly brought into interference with the soil gas detection result. The sampling system 2 is assembled without using any interference materials, and the connection among all the parts adopts a stainless steel or copper ferrule joint connection mode, so that the air tightness requirement can be met.
In order to make the sample of soil gas collection be representative, the soil gas monitoring well and the soil gas sampling system 2 which are constructed are required to be confirmed to meet the air tightness requirement, and the test work of the air tightness of the soil gas monitoring well and the air tightness of the soil gas sampling system 2 can be carried out.
In order to ensure the air tightness of the soil gas sampling system 2, the components of the utility model are connected by adopting a stainless steel or copper ferrule joint connection mode, so that the air tightness requirement can be met.
To ensure that there is no interference with the collected sample testing, the components of the sampling system 2 of the present utility model do not use any substances that interfere with the soil gas volatile organic testing, such as glue, tape, sealing rings, etc.
The soil gas monitoring sampling equipment that this scheme provided, during the in-service use, place gas collecting channel 1 to the soil gas monitoring well. After passing the well pipe in the soil gas monitoring well through the first port 101, it is connected to the first valve 201 of one of the sampling systems 2. The outside of the valve III 203 of the sampling system 2 is connected with a vacuum pump or a suction pump. After the connection is completed, the air tightness test of the sampling system 2 may be performed.
The specific steps of the air tightness test of the sampling system 2 are as follows:
1: closing the first valve 201, each second valve, and opening the third valve 203;
2: turning on the electronic negative pressure meter 205, and observing that the reading should be 0;
3: the vacuum pump or suction pump connected to the outside of valve three 203 is turned on to pump air. The following conditions are met, which indicate that the tightness of the sampling system 2 meets the technical requirements: and after the reading of 35KPa is displayed by the negative pressure meter or the reading of the negative pressure meter is stable, the valve III 203 is closed, the vacuum pump or the air pump is closed, the reading of the negative pressure meter is continuously observed for 5 minutes, the reading is recorded every 1 minute, and the reading change of the negative pressure meter is smaller than 1.5KPa. Otherwise, the joints are checked one by one until the air tightness of the system meets the technical requirements.
And the air tightness of the other groups of sampling systems 2 is detected according to the method, and after the technical requirements are met, the test work of the air tightness of the soil air monitoring well is carried out.
The soil gas monitoring well air tightness test comprises the following specific steps:
1: connecting a trace gas tank to port three 103, typically helium as the trace gas;
2: the gas collecting hood 1 is sealed so as not to allow the gas to escape directly;
3: maintaining port two 102 in communication with air;
4: the outer side of the valve III 203 is connected with a vacuum pump or an air pump;
5: valve one 201, each valve two and valve three 203 are kept in a closed state;
6: and opening a tracer gas source regulating valve to enable tracer gas to enter the gas collecting hood 1. Gas samples in the gas collecting hood 1 are collected at the second port 102 at intervals, and the concentration of the inert tracer gas is analyzed. Helium is selected as the tracer gas, and the volume percentage of helium in the gas collecting hood 1 is not less than 50%. Adopting other tracer gases, wherein the concentration of the tracer gases is at least 2 orders of magnitude higher than the detection limit of a corresponding gas field portable detector;
7: after the concentration of the trace gas in the gas collecting hood 1 reaches a required value, opening a valve I201 and a valve III 203, opening a vacuum pump or an air pump connected with the outer side of the valve III 203 to perform air extraction sampling on the outer side of the valve III 203, analyzing and collecting the concentration of the trace gas in the soil gas sample, if the concentration is lower than 10%, considering that the air tightness of the soil gas monitoring well meets the technical requirement, otherwise, discarding the well, and newly building a soil gas monitoring well meeting the air tightness technical requirement outside the diameter range of 1.5m of the well; if the air tightness of the soil air monitoring well meets the technical requirements, the air tightness test is not needed to be carried out again before each sampling.
After the air tightness test of the soil gas monitoring well is completed and the requirements are met, the collection work of the soil gas sample can be carried out.
For any group of sampling systems 2, the specific steps of soil gas sample collection are as follows:
1: removing the gas collecting hood 1, and connecting a well pipe and a valve I201;
2: connecting a consumable (a soda tank, an adsorbent tube or an air bag sampling tank) to one of the valves II, such as valve II A;
3: after the connection is completed, the valve I201 and the valve II A are synchronously opened, and the opening direction of the valve I201 is the direction from the interface to the electronic negative pressure meter 205. When a soil gas parallel sample is to be collected, the agate jar, the adsorbent tube or the air bag sampling box is respectively connected to the second valves, the first valve 201 is synchronously opened during sampling, and the opening direction of the first valve 201 is still the direction of the interface to the electronic negative pressure meter 205.
4: after the system is connected, a vacuum pump or an air extracting pump is started to begin air extraction. And adjusting the flow of a vacuum pump or an air pump according to the reading of the flowmeter, ensuring that the well flushing rate is not higher than 200mL/min, observing the reading of a negative pressure meter, ensuring that the negative pressure of the system is not higher than 2.5KPa, ensuring that the soil permeability near a sampling point is poor, reducing the sampling rate to 100mL/min, and ensuring that the negative pressure of the system cannot be higher than 2.5KPa. If the pressure is higher than the value, the sampling is stopped immediately, the first valve 201 and the second valve which is opened are closed, and the sampling is continued after the pressure of the system is recovered, and the process is repeated until the volume of the collected sample meets the analysis requirement; the sample collection amount is determined according to the required detection limit and the analysis method, but is not more than 1.0L;
5: after the sample collection is completed, the valve II which is opened is closed, then the vacuum sampling pump is closed, the valve I201 is closed, the collected sample is stored in a dark place, and the sample is sent to a laboratory for analysis as soon as possible.
After the collection is completed, the connection between the gas collecting hood 1 and the sampling system 2 is disconnected, and the collection is completed and the next sampling point position is moved to complete the sampling work.
When the multiple groups of sampling systems 2 are used for sampling soil gas with different depths in the same well, the well pipes corresponding to different well depths are connected with the first valves 201, and the sampling modes of the sampling systems 2 in each group are the same.
In another technical scheme, in the soil gas monitoring and sampling device, the gas collecting hood 1 is a cylinder with a hollow inside and one open bottom surface.
In another technical scheme, in the soil gas monitoring and sampling device, the first port 101 and the second port 102 are both arranged on the side wall of the gas collecting hood 1, and the third port 103 is arranged on the other bottom surface of the gas collecting hood 1.
In another technical scheme, in the soil gas monitoring and sampling device, the first port 101 and the second port 102 are located at two sides of the side wall of the gas collecting hood 1.
In another embodiment, in the soil gas monitoring and sampling apparatus, the sampling system 2 has two groups.
In another aspect, in the soil gas monitoring and sampling apparatus, any one of the groups of sampling systems 2 further includes:
a second branch conduit 208 which is communicated with a part of the main conduit 206 between the electronic flowmeter 204 and the electronic negative pressure meter 205, and a knob valve is arranged on the second branch conduit 208;
a PID tester 209 connected to the main conduit 206 via a second branch conduit 208.
In practical application, preliminary judgment of soil gas concentration in the early stage is one of key steps for accurately executing projects. Under different gas concentrations, different sampling adsorption or receiving consumables or different sampling volumes are selected, so that the method plays a decisive role in subsequent result analysis. Using the results of the PID test as a preliminary judgment before sampling is the preferred way to consider cost and efficiency in the state of the art.
By integrating the PID tester 209, a preliminary determination is made as to the concentration of the soil gas in order to select an appropriate sampling consumable or sampling volume.
The soil gas monitoring sampling equipment that this scheme provided, during the in-service use, place gas collecting channel 1 to the soil gas monitoring well. After passing the well pipe in the soil gas monitoring well through the first port 101, it is connected to the first valve 201 of one of the sampling systems 2. The outside of the valve III 203 of the sampling system 2 is connected with a vacuum pump or a suction pump. After the connection is completed, the air tightness test of the sampling system 2 may be performed.
The specific steps of the air tightness test of the sampling system 2 are as follows:
1: closing the first valve 201, each second valve, and opening the third valve 203;
2: turning on the electronic negative pressure meter 205, and observing that the reading should be 0;
3: the vacuum pump or suction pump connected to the outside of valve three 203 is turned on to pump air. The following conditions are met, which indicate that the tightness of the sampling system 2 meets the technical requirements: and after the reading of 35KPa is displayed by the negative pressure meter or the reading of the negative pressure meter is stable, the valve III 203 is closed, the vacuum pump or the air pump is closed, the reading of the negative pressure meter is continuously observed for 5 minutes, the reading is recorded every 1 minute, and the reading change of the negative pressure meter is smaller than 1.5KPa. Otherwise, the joints are checked one by one until the air tightness of the system meets the technical requirements.
The air tightness of the other groups of sampling systems 2 is detected according to the method, and after the technical requirements are met, the test work of the air tightness of the soil air monitoring well is carried out.
The soil gas monitoring well air tightness test comprises the following specific steps:
1: connecting a trace gas tank to port three 103, typically helium as the trace gas;
2: the gas collecting hood 1 is sealed so as not to allow the gas to escape directly;
3: maintaining port two 102 in communication with air;
4: the outer side of the valve III 203 is connected with a vacuum pump or an air pump;
5: valve one 201, valve two, valve three 203 and knob valve all keep the closed state;
6: and opening a tracer gas source regulating valve to enable tracer gas to enter the gas collecting hood 1. Gas samples in the gas collecting hood 1 are collected at the second port 102 at intervals, and the concentration of the inert tracer gas is analyzed. Helium is selected as the tracer gas, and the volume percentage of helium in the gas collecting hood 1 is not less than 50%. Adopting other tracer gases, wherein the concentration of the tracer gases is at least 2 orders of magnitude higher than the detection limit of a corresponding gas field portable detector;
7: after the concentration of the trace gas in the gas collecting hood 1 reaches a required value, opening a valve I201 and a valve III 203, opening a vacuum pump or an air pump connected with the outer side of the valve III 203 to perform air extraction sampling on the outer side of the valve III 203, analyzing and collecting the concentration of the trace gas in the soil gas sample, if the concentration is lower than 10%, considering that the air tightness of the soil gas monitoring well meets the technical requirement, otherwise, discarding the well, and newly building a soil gas monitoring well meeting the air tightness technical requirement outside the diameter range of 1.5m of the well; if the air tightness of the soil air monitoring well meets the technical requirements, the air tightness test is not needed to be carried out again before each sampling.
After the air tightness test of the soil gas monitoring well is completed and the requirements are met, the collection work of the soil gas sample can be carried out.
For any group of sampling systems 2, the specific steps of soil gas sample collection are as follows:
1: removing the gas collecting hood 1, and connecting a well pipe and a valve I201;
2: opening a first valve 201 and a knob valve, keeping the second valve and the third valve 203 closed, testing PID values, confirming sampling consumable materials and sampling volumes, and closing the knob valve after the testing is finished;
3: connecting a consumable (a soda tank, an adsorbent tube or an air bag sampling tank) to one of the valves II, such as valve II A;
4: after the connection is completed, the valve I201 and the valve II A are synchronously opened, and the opening direction of the valve I201 is the direction from the interface to the electronic negative pressure meter 205. When a soil gas parallel sample is to be collected, the agate jar, the adsorbent tube or the air bag sampling box is respectively connected to the second valves, the first valve 201 is synchronously opened during sampling, and the opening direction of the first valve 201 is still the direction of the interface to the electronic negative pressure meter 205.
5: after the system is connected, a vacuum pump or an air extracting pump is started to begin air extraction. And adjusting the flow of a vacuum pump or an air pump according to the reading of the flowmeter, ensuring that the well flushing rate is not higher than 200mL/min, observing the reading of a negative pressure meter, ensuring that the negative pressure of the system is not higher than 2.5KPa, ensuring that the soil permeability near a sampling point is poor, reducing the sampling rate to 100mL/min, and ensuring that the negative pressure of the system cannot be higher than 2.5KPa. If the pressure is higher than the value, the sampling is stopped immediately, the first valve 201 and the second valve which is opened are closed, and the sampling is continued after the pressure of the system is recovered, and the process is repeated until the volume of the collected sample meets the analysis requirement; the sample collection amount is determined according to the required detection limit and the analysis method, but is not more than 1.0L;
6: after the sample collection is completed, the valve II which is opened is closed, then the vacuum sampling pump is closed, the valve I201 is closed, the collected sample is stored in a dark place, and the sample is sent to a laboratory for analysis as soon as possible.
After the collection is completed, the connection between the gas collecting hood 1 and the sampling system 2 is disconnected, and the collection is completed and the next sampling point position is moved to complete the sampling work.
When the multiple groups of sampling systems 2 are used for sampling soil gas with different depths in the same well, the well pipes corresponding to different well depths are connected with the first valves 201, and the sampling modes of the sampling systems 2 in each group are the same.
In another aspect, in the soil gas monitoring and sampling device, the knob valve is located between the PID tester 209 and the main pipe 206.
In another technical scheme, in the soil gas monitoring and sampling device, the inner diameter of the gas collecting hood 1 is 30cm, so that the gas collecting hood can complete the gas tightness test of soil gas monitoring wells with different diameters, the diameters of which are smaller than 30cm.
In another technical scheme, in the soil gas monitoring and sampling device, two valves, namely a valve II A and a valve II B, are arranged.
The soil gas monitoring sampling equipment that this scheme provided, during the in-service use, place gas collecting channel 1 to the soil gas monitoring well. After passing the well pipe in the soil gas monitoring well through the first port 101, it is connected to the first valve 201 of one of the sampling systems 2. The outside of the valve III 203 of the sampling system 2 is connected with a vacuum pump or a suction pump. After the connection is completed, the air tightness test of the sampling system 2 may be performed.
The specific steps of the air tightness test of the sampling system 2 are as follows:
1: closing the valve I201, the valve II A and the valve II B, and opening the valve III 203;
2: turning on the electronic negative pressure meter 205, and observing that the reading should be 0;
3: the vacuum pump or suction pump connected to the outside of valve three 203 is turned on to pump air. The following conditions are met, which indicate that the tightness of the sampling system 2 meets the technical requirements: and after the reading of 35KPa is displayed by the negative pressure meter or the reading of the negative pressure meter is stable, the valve III 203 is closed, the vacuum pump or the air pump is closed, the reading of the negative pressure meter is continuously observed for 5 minutes, the reading is recorded every 1 minute, and the reading change of the negative pressure meter is smaller than 1.5KPa. Otherwise, the joints are checked one by one until the air tightness of the system meets the technical requirements.
The air tightness of the other groups of sampling systems 2 is detected according to the method, and after the technical requirements are met, the test work of the air tightness of the soil air monitoring well is carried out.
The soil gas monitoring well air tightness test comprises the following specific steps:
1: connecting a trace gas tank to port three 103, typically helium as the trace gas;
2: the gas collecting hood 1 is sealed so as not to allow the gas to escape directly;
3: maintaining port two 102 in communication with air;
4: the outer side of the valve III 203 is connected with a vacuum pump or an air pump;
5: valve one 201, valve two A, valve two B, valve three 203 all keep the closed state;
6: and opening a tracer gas source regulating valve to enable tracer gas to enter the gas collecting hood 1. Gas samples in the gas collecting hood 1 are collected at the second port 102 at intervals, and the concentration of the inert tracer gas is analyzed. Helium is selected as the tracer gas, and the volume percentage of helium in the gas collecting hood 1 is not less than 50%. Adopting other tracer gases, wherein the concentration of the tracer gases is at least 2 orders of magnitude higher than the detection limit of a corresponding gas field portable detector;
7: after the concentration of the trace gas in the gas collecting hood 1 reaches a required value, opening a valve I201 and a valve III 203, opening a vacuum pump or an air pump connected with the outer side of the valve III 203 to perform air extraction sampling on the outer side of the valve III 203, analyzing and collecting the concentration of the trace gas in the soil gas sample, if the concentration is lower than 10%, considering that the air tightness of the soil gas monitoring well meets the technical requirement, otherwise, discarding the well, and newly building a soil gas monitoring well meeting the air tightness technical requirement outside the diameter range of 1.5m of the well; if the air tightness of the soil air monitoring well meets the technical requirements, the air tightness test is not needed to be carried out again before each sampling.
After the air tightness test of the soil gas monitoring well is completed and the requirements are met, the collection work of the soil gas sample can be carried out.
For any group of sampling systems 2, the specific steps of soil gas sample collection are as follows:
1: removing the gas collecting hood 1, and connecting a well pipe and a valve I201;
2: connecting consumable (a Suma tank, an adsorbent tube or an air bag sampling box) to the valve II A or the valve II B;
3: after the connection is completed, the valve I201 and the valve II A or the valve II B are synchronously opened, and the opening direction of the valve I201 is the direction from the interface to the electronic negative pressure meter 205. When a soil gas parallel sample is to be collected, a agaric tank, an adsorbent tube or an air bag sampling box is connected to a valve A and a valve B, a valve A201 is synchronously opened during sampling, the valve A and the valve B are both opened, and the opening direction of the valve A201 is still the direction of connecting to the electronic negative pressure meter 205.
4: after the system is connected, a vacuum pump or an air extracting pump is started to begin air extraction. And adjusting the flow of a vacuum pump or an air pump according to the reading of the flowmeter, ensuring that the well flushing rate is not higher than 200mL/min, observing the reading of a negative pressure meter, ensuring that the negative pressure of the system is not higher than 2.5KPa, ensuring that the soil permeability near a sampling point is poor, reducing the sampling rate to 100mL/min, and ensuring that the negative pressure of the system cannot be higher than 2.5KPa. If the pressure is higher than the value, the sampling is stopped immediately, the first valve 201 and the second valve which is opened are closed, and the sampling is continued after the pressure of the system is recovered, and the process is repeated until the volume of the collected sample meets the analysis requirement; the sample collection amount is determined according to the required detection limit and the analysis method, but is not more than 1.0L;
5: after the sample collection is completed, the valve II which is opened is closed, then the vacuum sampling pump is closed, the valve I201 is closed, the collected sample is stored in a dark place, and the sample is sent to a laboratory for analysis as soon as possible.
After the collection is completed, the connection between the gas collecting hood 1 and the sampling system 2 is disconnected, and the collection is completed and the next sampling point position is moved to complete the sampling work.
When the multiple groups of sampling systems 2 are used for sampling soil gas with different depths in the same well, the well pipes corresponding to different well depths are connected with the first valves 201, and the sampling modes of the multiple groups of sampling systems 2 are the same.
In another technical scheme, in the soil gas monitoring and sampling device, the main pipe is connected with a vacuum pump/air pump, and the valve III is located between the vacuum pump/air pump and the valve I.
Although embodiments of the present utility model have been disclosed above, it is not limited to the details and embodiments shown and described, it is well suited to various fields of use for which the utility model would be readily apparent to those skilled in the art, and accordingly, the utility model is not limited to the specific details and illustrations shown and described herein, without departing from the general concepts defined in the claims and their equivalents.
Claims (10)
1. Soil gas monitoring sampling equipment, its characterized in that includes:
the gas collecting hood is provided with a first port, a second port and a third port;
the system comprises at least one group of sampling systems, wherein any group of sampling systems comprises a valve I, a plurality of valves II, a valve III, an electronic flowmeter, an electronic negative pressure meter, a main conduit and a plurality of first branch conduits, and one valve II is arranged on one first branch conduit; the valve I, the electronic flowmeter, the electronic negative pressure meter and the valve III are sequentially connected through a main conduit, and the two first branch conduits are respectively communicated with a part of the main conduit, which is positioned between the electronic negative pressure meter and the valve III; when the air tightness of the soil air monitoring well is verified, a well pipe in the soil air monitoring well penetrates through the port and is selectively connected with one valve I.
2. The soil gas monitoring and sampling apparatus according to claim 1, wherein the gas collecting channel is cylindrical with a hollow interior and one of its bottom surfaces open.
3. The soil gas monitoring and sampling apparatus of claim 2, wherein the first port and the second port are both disposed on a sidewall of the gas-collecting hood, and the third port is disposed on the other bottom surface of the gas-collecting hood.
4. A soil gas monitoring sampling apparatus according to claim 3, wherein the first and second ports are located on either side of the side wall of the gas-collecting channel.
5. The soil gas monitoring sampling apparatus of claim 1, wherein the sampling system has two sets.
6. The soil gas monitoring sampling apparatus of claim 1, wherein any one of the sets of sampling systems further comprises:
the second branch conduit is communicated with a part of the main conduit, which is positioned between the electronic flowmeter and the electronic negative pressure meter, and is provided with a knob valve;
and the PID tester is connected with the main pipe through the second branch pipe.
7. The soil gas monitoring sampling apparatus of claim 6, wherein the knob valve is located between the PID tester and the main conduit.
8. The soil gas monitoring sampling apparatus of claim 2, wherein the gas collection housing has an inner diameter of 30cm.
9. The soil gas monitoring sampling apparatus of claim 1, wherein there are two of said valves two.
10. The soil gas monitoring and sampling apparatus of claim 1, wherein the main conduit is connected to a vacuum pump/pump, and a valve three is located between the vacuum pump/pump and the valve one.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202321974104.3U CN220490501U (en) | 2023-07-26 | 2023-07-26 | Soil gas monitoring sampling equipment |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321974104.3U CN220490501U (en) | 2023-07-26 | 2023-07-26 | Soil gas monitoring sampling equipment |
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| CN220490501U true CN220490501U (en) | 2024-02-13 |
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| CN202321974104.3U Active CN220490501U (en) | 2023-07-26 | 2023-07-26 | Soil gas monitoring sampling equipment |
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