Gas sampling storage device and sampling method thereof

Abstract

The present invention relates to the field of petroleum and natural gas geological experiment technology, and specifically to a gas sampling storage device and a sampling method thereof, wherein the storage chamber and the flow passage adopt a double-space design to avoid the discharge of gas from the air inlet passage, so that the gas sampling work can be completed without turning the gas sampling storage device upside down, and the upright sampling avoids the process of placing the gas sampling storage device in a saturated filling liquid to prevent the saturated filling liquid from being discharged during the inverted sampling. The present invention does not need to place the gas sampling storage device in a saturated filling liquid but can directly complete the gas collection in a normal space. When the gas sample is drawn for analysis, the gas sampling needle enters the gas through the rubber plug of the gas sampling opening to absorb the gas, and there is no risk of the gas sampling needle being blocked. Thus, the purpose of simply, quickly, safely and conveniently sampling natural gas (associated gas) is achieved, the work efficiency is improved, and the collection difficulty and work threshold are greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum and natural gas geological experiments, and in particular to a gas sampling storage device and a sampling method thereof. Background Art

[0002] In the process of oil and gas exploration and development, the component analysis and component carbon isotope analysis of crude oil associated gas and natural gas are the main parameters for geological research applications such as natural gas (associated gas) type classification, natural gas (associated gas) genesis identification, gas / gas and gas / source comparison. At present, there are three main sampling containers and methods used by various oil and gas fields and scientific research institutions, namely high-pressure steel cylinder sampling, gas sampling bag sampling and glass brine bottle drainage gas sampling.

[0003] The high-pressure cylinder sampling method is suitable for situations where the wellhead pressure is high and the gas samples need to be stored for a long time. However, the capacity of the high-pressure cylinder is relatively large, and the gas in the cylinder must be taken to a certain pressure to meet the analysis and testing requirements. The large capacity and high pressure requirements result in a long sampling time for the high-pressure cylinder. Due to the material, the high-pressure cylinder is heavy and difficult to carry when collecting samples. Therefore, it is not suitable for collection occasions where the sampling volume is small and the sample is quickly tested.

[0004] The gas sampling bag sampling method is suitable for the collection requirements of small sampling volume and rapid sample detection. However, the inner membrane of the gas sampling bag is very easy to adsorb light carbon isotopes in the gas component, resulting in a heavy carbon isotope ratio. Therefore, the gas sampling bag sampling method is suitable for samples that are only tested for natural gas components, but not for samples that need carbon isotope detection. In the process of draining water and collecting gas from a glass salt water bottle, a basin or cylinder filled with saturated filling liquid is used. The depth of the saturated filling liquid is greater than the height of the bottle body. The bottle body is first immersed in the saturated filling liquid upright, and the salt water fills the entire bottle body. At this time, the bottle body is inverted, and the gas collection pipeline is extended from the bottle mouth underwater into the bottle mouth. The gas valve is opened, and the gas rises from the bottle mouth to the bottom of the bottle and discharges the salt water in the bottle. When the gas sampling volume is reached, the gas valve is closed, the gas collection pipeline is drawn out, and the bottle mouth is blocked with a flip-mouth rubber plug underwater, and the flip of the flip-mouth rubber plug is turned back, and the gas collection is completed.

[0005] The glass brine bottle drainage gas collection method is suitable for the collection requirements of small sampling volume and rapid sample detection, and the glass and saturated filling liquid will not undergo carbon isotope fractionation reaction with the sample. This collection method is applicable to both natural gas composition and carbon isotope analysis of the sample. However, the sampling process of the saturated filling liquid bottle water drainage gas sampling method must be operated in a basin or bucket filled with saturated filling liquid. Generally, natural gas or crude oil associated gas wellheads are far away from human habitation, and the on-site conditions are difficult. Water is often not found on site, resulting in the inability to sample. When sampling in northern regions in winter, gas collectors must operate in ice water at a temperature below 0°C. Being in 0°C water for a long time is very likely to cause frostbite on the hands and poor finger flexibility, resulting in operational errors and sampling failure. When sampling, the saline bottle is inverted in the saturated filling liquid for gas extraction. During the operation, the saline bottle cannot be upright, and no part of the bottle body can exceed the water surface. In addition, the bottle body must be held in one hand, and the flip-mouth rubber stopper must be inserted with one hand and the flip-mouth turned back. During this process, if the bottle body is tilted, part of the bottle body is higher than the water surface, the rubber stopper cannot be inserted into the bottle mouth, etc., sampling failure will occur. The saturated filling liquid bottle water drainage gas sampling method has high physical and operational requirements for gas collectors, and requires specialized gas collectors to complete sampling.

[0006] In addition, the gas sampling bottle and its use method disclosed in the publication number CN108982169A, wherein the sampling bottle is composed of a bottle body, an inner cover forming an inner cavity with the bottle body, a one-way valve for the gas sample to enter the inner cavity when collecting the gas sample, a straight-through gas nozzle for discharging the liquid in the inner cavity when collecting the gas sample, a rubber sleeve for sealing the straight-through gas nozzle and an outer cover covering the bottle body. The sampling bottle has a complex structure, many connecting devices such as various interface valves, a high manufacturing cost and is very likely to reduce the air tightness of the sampling bottle; when collecting gas and taking out the gas sample, the sampling bottle The bottle must be inverted, and the analyst must hold the bottle with one hand while installing and removing the rubber sleeve and using the sampling needle to absorb the sample with one hand, which is extremely difficult to operate. When the sampling needle is used to absorb the sample, the needle must pass through the saturated filling liquid to reach the gas sample to absorb the sample. When the needle passes through the saturated filling liquid, it will be blocked by the saturated filling liquid and cannot absorb the sample. In addition, the balance composed of capillary force, gas sample pressure, saturated filling liquid gravity and air pressure can easily be destroyed by the air mixed in when the needle is inserted, causing the saturated filling liquid and gas sample to escape and be lost. Summary of the invention

[0007] The present invention overcomes the deficiencies of the prior art and provides a gas sample storage device and a sampling method thereof, which particularly has the characteristics of simple and sophisticated structure, good air tightness, simple operation, good applicability, high sampling success rate, low operating threshold for gas collectors, and protection of the health and safety of collectors.

[0008] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0009] A gas sampling storage device, comprising

[0010] A storage body, wherein the storage body has a storage cavity;

[0011] A flow passage, wherein the flow passage is arranged on one side of the storage chamber, and the bottom of the flow passage is communicated with the bottom of the storage chamber, and the top of the flow passage is communicated with the outside;

[0012] An air intake passage, the air intake passage being in communication with the storage chamber;

[0013] The top of the storage cavity is provided with an air intake opening for taking out air.

[0014] Furthermore, the top of the flow passage is a first communication port connected to the outside, the air intake opening is a second communication port, and the first communication port forms a communication channel with the flow passage, the storage cavity and the second communication port.

[0015] Furthermore, the flow passage is a part of the storage body, and is separated by a separator to form the flow passage.

[0016] Furthermore, the air inlet channel is located in the flow channel, and a guide groove is provided in the flow channel.

[0017] Furthermore, a guide portion is provided at the point where the bottom of the flow passage communicates with the bottom of the storage chamber.

[0018] Furthermore, the guide portion is located at the bottom of the storage cavity, and the guide portion is provided with an inclined surface, which extends to the bottom of the flow channel and communicates with the bottom of the storage cavity.

[0019] Furthermore, the opening at the top of the flow passage communicating with the outside is the same opening as the inlet of the air intake passage, and the opening is located at the top of the storage cavity.

[0020] Furthermore, the outlet of the air inlet passage is located at the bottom of the storage cavity.

[0021] Furthermore, the first communication port and the second communication port are both provided with detachable flexible sealing members.

[0022] A method for sampling a gas sample storage device, comprising a gas sample storage device as described in any one of the above, comprising the following method

[0023] Before collecting gas samples on site, fill the gas sample storage container with saturated filling liquid;

[0024] A flexible seal is used to seal the opening at the top of the flow channel connected to the outside and the gas extraction opening at the top of the storage chamber. Then, the gas extraction sample storage device is brought to the sampling site, placed on a flat surface, and the opening at the top of the flow channel connected to the outside is opened.

[0025] The external sampling gas is passed through the gas pipeline and then injected into the storage cavity through the air inlet channel. The sampling gas rises and gathers in the storage cavity containing the saturated filling liquid and converges at the top of the storage cavity. The sampling gas squeezes the saturated filling liquid, and the saturated filling liquid flows out from the opening at the top of the flow channel that is connected to the outside.

[0026] When the volume of the sampled gas reaches the sampling volume requirement, the gas valve is closed, the gas pipeline is disconnected, and the opening at the top of the flow channel connected to the outside is sealed by a flexible seal, and the sampling is completed;

[0027] When sampling gas needs to be extracted for analysis, since the sampling gas is at the top of the storage cavity at this time, a gas extraction needle is used to enter the storage cavity through the flexible sealing member on the gas extraction opening at the top of the storage cavity and directly absorb the gas.

[0028] The beneficial effects of the present invention are:

[0029] Compared with the prior art, the gas sample storage device and the sampling method of the gas sample storage device of the present invention are simple and easy to operate in the process of collecting, storing samples and testing and analyzing natural gas and crude oil associated gas. During the sampling process of the gas sample storage device of the present invention, the gas sample storage device does not need to be placed in saturated salt water or inverted. During gas collection, sealing with rubber plugs and taking out samples, the gas sample storage device is placed upright in a normal space. The gas sample storage device can be placed securely and operated with both hands. The operation is simple, and ordinary personnel can also operate the sampling at will. When taking out the sample, the gas needle directly enters the gas, and there is no risk of needle tube blockage and gas loss. The gas sample storage device has good applicability, a high sampling success rate, and a low operating threshold for gas collectors, which protects the health and safety of the collectors and achieves the purpose that the present invention wants to achieve. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0031] Figure 1 It is a schematic diagram of the overall front view structure of the present invention.

[0032] Figure 2 It is a schematic diagram of the overall side structure of the present invention.

[0033] In the figure: 1- storage body, 2- flow channel, 3- storage chamber, 4- partition, 5- first connecting port, 6- second connecting port, 7- guide groove, 8- guide part. DETAILED DESCRIPTION

[0034] The following will describe in detail the technical solution of a gas sampling storage device and a sampling method thereof provided by the embodiments of the present invention through several specific embodiments.

[0035] Embodiment 1:

[0036] Reference Figure 1 , a gas sampling storage device, comprising

[0037] A storage body 1, wherein the storage body 1 has a storage cavity 3;

[0038] A flow passage 2, wherein the flow passage 2 is arranged on one side of the storage chamber 3, and the bottom of the flow passage 2 is communicated with the bottom of the storage chamber 3, and the top of the flow passage 2 is communicated with the outside;

[0039] An air intake passage, the air intake passage being in communication with the storage chamber 3;

[0040] The top of the storage cavity 3 is provided with an air intake opening for taking out air.

[0041] The storage body 1 can be an integral structure with a storage cavity 3, and the flow channel 2 is a combined structure located on one side of the storage cavity 3, wherein the cavity of the entire storage cavity 3 is larger than the entire cavity of the flow channel 2, and the flow channel 2 is used as a back-osmosis outlet channel for the liquid.

[0042] The air inlet passage may be an air inlet port connected to the storage chamber 3 , and the air inlet port may share a common port with the air intake opening at the top of the storage chamber 3 , or may be arranged at any position on the storage body 1 that can be connected to the storage chamber 3 .

[0043] A one-way air inlet valve can be provided on the air inlet, and the air inlet channel can also be located at the bottom of the storage chamber 3. When the external sampling gas is connected to the one-way air inlet valve on the air inlet through the air inlet pipeline, the gas enters the storage chamber 3. When using the air sampling sample storage device, it is necessary to fill the entire storage chamber 3 and the flow channel 2 with saturated filling liquid in advance, and then seal the air intake opening at the top of the storage chamber 3, open the opening at the top of the flow channel 2 that is connected to the outside, and the incoming gas squeezes the saturated filling liquid, and the saturated filling liquid seeps out from the flow channel 2. After enough gas is collected, the opening at the top of the flow channel 2 is sealed. The one-way air inlet valve on the air inlet is sealed to prevent the atmosphere from entering the storage chamber 3.

[0044] The air intake opening at the top of the storage chamber 3 is used for taking out air, and is also used as an inlet for filling with saturated filling liquid.

[0045] The top of the flow passage 2 is a first communication port 5 communicating with the outside, and the air extraction opening is a second communication port 6. The first communication port 5 forms a communication passage with the flow passage 2, the storage chamber 3 and the second communication port 6. The purpose of forming the communication passage is to allow the saturated filling liquid in the storage chamber 3 to seep out from the first communication port 5 when air is extracted.

[0046] The first communication port 5 and the second communication port 6 are both provided with a detachable flexible seal. The flexible seal can be sealed with a matching turn-over rubber plug, which is convenient for removal and installation. After installation, the turn-over rubber plug can be turned over and sealed, and the sealing effect is good.

[0047] The flow passage 2 can also be a part of the storage body 1, that is, an integral structure, separated by a separator 4 to form the flow passage 2. The storage body 1 is an integral cavity structure, and the cavity can be the storage cavity 3. Then, a flow passage 2 with two ends opened is separated by a separator 4 on the inner wall of one side where the storage cavity 3 is located. The bottom of the flow passage 2 is connected to the bottom of the storage cavity 3, wherein the opening at the top of the flow passage 2 connected to the outside and the entrance of the air inlet passage can also be the same opening, and the opening is located at the top of the storage cavity 3. Gas can pass through the flow passage 2 into the storage cavity 3 through a pipeline, ensuring that the flow passage 2 has a certain length, that is, height. The flow passage 2 occupies four-fifths of the height of the entire storage body 1 for the best effect. The longer flow passage 2 avoids the entry of the atmosphere during the saturated filling liquid back-infiltration process, and further plays a sealing role. The outlet of the air inlet passage is located at the bottom of the storage cavity 3, ensuring that the gas can enter the storage cavity 3 without contacting the atmosphere.

[0048] The saturated filling liquid may be saturated salt water.

[0049] Embodiment 2:

[0050] Furthermore, the air inlet channel is located in the flow channel 2 , and a guide groove 7 is provided in the flow channel 2 .

[0051] Furthermore, a guide portion 8 is provided at the point where the bottom of the flow passage 2 communicates with the bottom of the storage chamber 3 .

[0052] Furthermore, the guide portion 8 is located at the bottom of the storage chamber 3 , and the guide portion 8 is provided with an inclined surface, which extends to the bottom of the flow channel 2 and the bottom of the storage chamber 3 .

[0053] In this embodiment, the air inlet channel can be the same channel as the flow channel 2. When gas sampling is performed, the sampling gas pipeline is inserted into the flow channel 2 and extends along the inner wall of the flow channel 2 to the bottom of the flow channel 2. The sampling gas pipeline can be a silicone pipeline or a latex pipeline, which is easy to insert. In order to ensure that the gas pipeline can be accurately inserted into the bottom of the storage chamber 3, a guide groove 7 is provided on the inner wall of the partition 4 located in the flow channel 2 along the direction in which the gas pipeline is inserted, which is used for guiding the gas pipeline. At the same time, in order to prevent the gas pipeline from extending into the bottom of the flow channel 2, that is, when the sampling gas is introduced at this time, a part of the gas will It enters the storage chamber 3 or cannot directly enter the storage chamber 3, and is directly discharged in the reverse direction from the flow channel 2, so a guide portion 8 is further provided at the connection point between the bottom of the flow channel 2 and the bottom of the storage chamber 3, wherein the guide portion 8 is a triangular structure, wherein two adjacent sides of the guide portion 8 are close to the bottom of the storage chamber 3 and the inner wall adjacent to the bottom, and the other side is an inclined surface with a guiding function, which extends from the bottom of the storage chamber 3 to the connection point between the bottom of the flow channel 2 and the bottom of the storage chamber 3, so that when the gas pipeline reaches this position, the end of the gas pipeline can be directly guided to extend into the bottom of the storage chamber 3, thereby ensuring that the input sampling gas can directly enter the storage chamber 3.

[0054] The inclined surface on the guide portion 8 may be an inclined surface with a certain concave curvature, and the separator 4 located at the bottom of the flow channel 2 and the bottom of the storage chamber 3 may be provided with an inclined surface inclined toward the storage chamber 3, and the inclined surface has the same inclination angle as the inclined surface on the guide portion 8, so that the two inclined surfaces form a guiding space for guiding the gas pipeline.

[0055] Embodiment 3:

[0056] This embodiment is described by taking the gas sampling sample storage device described in the present invention as a sample bottle made of glass as an example, wherein the entire sample bottle is an integrated structure, and the flow channel 2 is located in the entire glass sample bottle. The bottom of the cavity is connected to the storage cavity 3 at a certain height. The flow channel 2 is formed by a glass separator made of glass material, and the glass separator is arranged along the overall external bottle shape of the entire sample bottle to form a cavity structure of the flow channel 2. The glass separator is provided with an inwardly concave guide groove 7 with a diameter of about 1 cm. The guide groove 7 can pass through the entire glass separator, and the groove body of the guide groove 7 itself is not connected to the storage cavity 3. A guide portion 8 is also provided at the connection between the bottom of the flow channel 2 and the bottom of the storage cavity 3 to ensure that the gas pipeline can directly reach the storage cavity 3. The guide portion 8 can be formed integrally with the same glass material as the entire glass sample bottle.

[0057] A method for sampling a gas sample storage device, comprising a gas sample storage device as described in any one of embodiments 1-2, comprising the following method, referring to Figure 1 and Figure 2 Provide a detailed description:

[0058] Before collecting gas samples on site, first fill the gas sample storage container with saturated salt water; that is, fill the storage chamber 3 and the flow channel 2 with saturated salt water, the top of the flow channel 2 is the first connecting port 5, and the top gas extraction opening of the storage chamber 3 is the second connecting port 6, first open the first connecting port 5 and the second connecting port 6, and after filling with saturated salt water, use a turn-over rubber plug to seal the first connecting port 5 and the second connecting port 6, then bring the gas sample storage container to the sampling site, place it on a flat surface, and open the first connecting port 5;

[0059] The external sampling gas passes through the gas pipeline, and the gas pipeline extends into the flow channel 2 through the first connecting port 5. At this time, the gas pipeline extends along the guide groove 7 on the glass partition to the connection between the flow channel 2 and the storage chamber 3, and then the end of the gas pipeline passes through the guide part 8 and extends into the bottom of the storage chamber 3. Then, the gas valve is opened, and the sampling gas is injected into the storage chamber 3 through the gas pipeline. The sampling gas rises and gathers in the storage chamber 3 containing saturated salt water, and converges at the top of the storage chamber 3. The sampling gas squeezes the saturated filling liquid, and the saturated filling liquid flows out from the first connecting port 5 at the top of the flow channel 2;

[0060] When the volume of the sampled gas reaches the sampling quantity requirement, close the gas valve, draw out the gas pipeline, and seal the first connecting port 5 at the top of the flow channel 2 with the flip-open rubber plug, and the sampling is completed; when sealing the first connecting port 5 again, it must be ensured that it is filled with saturated salt water. If it is not full, saturated salt water must be added before sealing to avoid the accumulation of air after sealing, which will cause the sampled gas to be impure.

[0061] When it is necessary to extract sample gas for analysis, the gas can be directly drawn into the storage chamber 3 through the gas extraction needle through the turn-over rubber plug on the second connecting port 6 to absorb the gas. Since the sample gas is at the top of the storage chamber 3 at this time, the sampling needle can directly enter the gas for absorption without passing through saturated salt water, and there is no risk of the needle being blocked by saturated salt water.

[0062] The present invention uses the above-mentioned gas sampling storage device and the sampling method of the gas sampling storage device to make the sampling bottle immediately operable in the normal space, and the operation is simple and easy. With this sampling bottle, ordinary staff can also perform gas collection work. The gas sampling storage device and the sampling method of the gas sampling storage device described in the present invention are simple and easy to operate in the process of collecting, storing and testing natural gas and associated gas of crude oil. The gas sampling storage device of the present invention can directly perform upright sampling, avoiding the process of placing the sample bottle in saturated salt water to prevent the discharge of saturated salt water during inverted sampling, so that the sample bottle does not need to be placed in saturated salt water and gas collection can be completed directly in the normal space. When the gas sample is drawn for analysis, the gas needle enters the gas through the rubber plug of the gas extraction opening to absorb the gas, and there is no risk of clogging of the gas needle. Thereby achieving the purpose of simple, fast, safe and convenient natural gas (associated gas) sampling, improving work efficiency, and greatly reducing the difficulty of collection and the threshold of work.

[0063] The above is a detailed description of the embodiments of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Within the knowledge scope of ordinary technicians in the field, various changes can be made without departing from the purpose of the present invention, which are all within the protection scope of this technology.

[0064] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0065] The technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A gas sampling storage device, characterized in that: include A storage body (1), wherein the storage body (1) has a storage cavity (3); A flow passage (2), wherein the flow passage (2) is arranged on one side of the storage chamber (3), the bottom of the flow passage (2) is connected to the bottom of the storage chamber (3), and the top of the flow passage (2) is connected to the outside; An air intake passage, the air intake passage being in communication with the storage chamber (3); The top of the storage cavity (3) is provided with an air intake opening for taking out air; The top of the flow passage (2) is a first communication port (5) communicating with the outside, the air intake opening is a second communication port (6), and the first communication port (5) forms a communication passage with the flow passage (2), the storage chamber (3) and the second communication port (6); The flow passage (2) is a part of the storage body (1), and is separated by a separator (4) to form the flow passage (2); The gas sampling storage device is a sample bottle made of glass, wherein the entire sample bottle is an integrated structure.

2. The gas sampling storage device according to claim 1, characterized in that: The air inlet channel is located in the flow channel (2), and a guide groove (7) is provided in the flow channel (2).

3. The gas sampling storage device according to claim 2, characterized in that: A guide portion (8) is also provided at the point where the bottom of the flow passage (2) communicates with the bottom of the storage chamber (3).

4. The gas sampling storage device according to claim 3 is characterized in that: The guide portion (8) is located at the bottom of the storage chamber (3), and the guide portion (8) is provided with an inclined surface, which extends to the bottom of the flow channel (2) and the connection point with the bottom of the storage chamber (3).

5. The gas sampling storage device according to claim 1, characterized in that: The opening at the top of the flow passage (2) communicating with the outside is the same opening as the entrance of the air intake passage, and the opening is located at the top of the storage chamber (3).

6. The gas sampling storage device according to claim 5, characterized in that: The outlet of the air inlet channel is located at the bottom of the storage chamber (3).

7. The gas sampling storage device according to claim 1, characterized in that: The first communication port (5) and the second communication port (6) are both provided with detachable flexible sealing components.

8. A sampling method for a gas sample storage device, comprising a gas sample storage device according to any one of claims 1 to 7, characterized in that: Includes the following methods Before collecting gas samples on site, fill the gas sample storage container with saturated filling liquid; A flexible seal is used to seal the opening at the top of the flow channel (2) communicating with the outside and the gas extraction opening at the top of the storage chamber (3), and then the gas extraction sample storage device is brought to the sampling site, placed on a flat surface, and the opening at the top of the flow channel (2) communicating with the outside is opened; The external sampling gas is passed through the gas pipeline and then injected into the storage chamber (3) through the air inlet channel. The sampling gas rises and gathers in the storage chamber (3) containing the saturated filling liquid and converges at the top of the storage chamber (3). The sampling gas squeezes the saturated filling liquid, and the saturated filling liquid flows out from the opening at the top of the flow channel (2) that is connected to the outside. When the volume of the sampled gas reaches the sampling volume requirement, the gas valve is closed, the gas pipeline is disconnected, and the opening at the top of the flow passage (2) communicating with the outside is sealed by a flexible sealing member, and the sampling is completed; When it is necessary to extract sample gas for analysis, since the sample gas is at the top of the storage chamber (3) at this time, a gas extraction needle is used to enter the storage chamber (3) through the flexible sealing member on the gas extraction opening at the top of the storage chamber (3) to directly extract the sample gas.

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