CN114577555A

CN114577555A - Gas sampling method by air bag method

Info

Publication number: CN114577555A
Application number: CN202210322288.9A
Authority: CN
Inventors: 丁泓皓; 秦铭磊; 卢静; 陆慧斌
Original assignee: Jiangsu Xinrui Environmental Monitoring Co ltd
Current assignee: Jiangsu Xinrui Environmental Monitoring Co ltd
Priority date: 2022-03-29
Filing date: 2022-03-29
Publication date: 2022-06-03

Abstract

The invention discloses an air bag method gas sampling method, S1, the early preparation of the device: s11, providing an air bag method gas sampling device; s2, starting the pressure control device, and starting the switch device and the inlet switch device on each branch pipe; s3, closing the inlet switch device and opening the exhaust switch device; s4, repeating the steps S2 to S6 until the replacement of the gas in the bag is completed, and closing each device; s5, sampling for the first time, starting a pressure control device, and starting a switch device and an inlet switch device on one branch pipe; s6, closing the first switch device for collecting the sampled gas, closing the pressure control device, and waiting for the next sampling time; s7, opening the pressure control device again, exhausting air from the air chamber, and starting a switch device on the second branch pipe; and S8, repeating S5 to S7 to finish the subsequent 3 times of sampling, wherein the method can acquire for many times at one time and in different periods, realize the replacement of the gas in the gas bag and the sampling pipe, and improve the sampling efficiency.

Description

Gas sampling method by air bag method

Technical Field

The invention relates to a sampling method, in particular to an air bag method gas sampling method.

Background

The air bag sampling is to collect a certain gas for analysis and determination, the sampling mode is determined according to the sampling purpose and the field condition, and the sampled sample is representative to obtain reliable basic data; the prior air bag method gas sampling device comprises a sampling pipe, the tail end of the sampling pipe is connected with an air bag, the air bag is arranged in a sealed air chamber, the outlet of the air bag is fixed at the upper end of the air chamber and is communicated with the tail part of the sampling pipe, the air chamber is connected with an electric air pump which can be switched by positive pressure and negative pressure, an electric heating wire is arranged in the sampling pipe, is used for heating the sampled gas to ensure that the temperature of the sampled gas reaches 120 ℃, the gas in the air bag needs to be replaced before sampling, generally, the mode is adopted that an electric air pump is firstly opened to ensure that the gas is subjected to negative pressure, the internal pressure of an air chamber is reduced, thus, the pressure in the air bag expands outwards to increase the volume of the air bag, thereby pumping the gas into the air bag, then the electric air pump is switched to positive pressure, so that the pressure of the air chamber is increased, the air in the air bag can be pressed out, and the air can be replaced after the steps are repeated, however, the sampling device has the following defects: 1. when the gas bag is replaced, the gas in the gas bag is discharged from the sampling pipe, and the gas which is replaced and discharged cannot be completely discharged from the sampling pipe due to the small volume of the gas bag, so that the discharged gas is still in the sampling pipe, the gas which is sampled is not completely sampled, and the result is inaccurate; 2. the existing gas bag method sampling device can only collect gas once, but under normal conditions, gas needs to be collected four times at one sampling point, so that the collecting process is very complicated, the gas bag needs to be frequently taken out and installed, then gas is replaced, and the like, so that the degree of needing manual participation is high, and the gas bag method sampling device is troublesome and labor-consuming; 3. although the temperature of the current air bag method collecting device is heated to 120 ℃, moisture becomes water vapor, but the temperature of the current air bag method collecting device is not kept constant after entering the air bag, so that the water vapor in the air bag can be condensed into water in the later-stage transportation process, and the liquid water can dissolve target detection substances in some gases, for example, when gas VOC (volatile organic compound) detection sampling is carried out, VOC can be dissolved in the water, so that the subsequent detection result is inaccurate.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the gas sampling method by the air bag method can acquire the gas for multiple times at one time and in different periods, realizes the replacement of the gas in the air bag and the sampling pipe, effectively reduces the factors influencing the result, and improves the sampling efficiency.

In order to solve the technical problems, the technical scheme of the invention is as follows: an air bag method gas sampling method, S1, the early preparation of the device:

s11, an air bag method gas sampling device, which comprises a sampling box, wherein the sampling box is internally provided with an air chamber and a placing cavity, the air bag is placed in the placing cavity, the placing cavity comprises a plurality of placing cavities, hollow holes communicated with the air chamber are arranged on the placing cavities, the air chamber is connected with a pressure control device for increasing or reducing pressure, each placing cavity is internally provided with one air bag, the inlets of the air bags are fixed at the upper end of the placing cavity, the inlets of the air bags are connected with a branch pipe, the branch pipes are connected with the sampling pipes through a main pipe, each branch pipe is provided with a branch switch device for opening or closing the branch pipe, an inlet switch device which is opened or closed is arranged between the header pipe and the sampling pipe, a first electric heating device which heats sampling gas is arranged on the sampling pipe, and the sampling pipe of the gas sampling device is arranged at a sampling point.

S2, starting the pressure control device to pump air into the air chamber, starting the branch switch device and the inlet switch device on each branch pipe, enabling the sample gas to sequentially pass through the sampling pipe, the main pipe and each branch pipe and then enter each air bag, and stopping pumping the pressure control device after the volume of each air bag expands and contacts with the side wall of the air chamber;

s3, the pressure control device switches the working state to supply air and pressurize the air chamber, and the air bag is extruded and exhausted;

s4, repeating the steps S2 to S3 for multiple times until the gas in the gas bag is replaced;

s5, when the first sampling time is reached, opening an inlet switch device and a branch switch device on one branch pipe, opening a pressure control device to exhaust the air chamber, enabling the sampled air to enter a corresponding air bag, and after the volume expansion of the air bag is contacted with the side wall of the air chamber, after closing the branch switch device on the branch pipe, stopping the air exhaust of the pressure control device, and waiting for the next sampling time;

s6, when the second sampling time is reached, repeating the step S5 to enable the sampling gas to enter a second air bag;

and S7, repeating the operation of the step S5 at the subsequent sampling time nodes in sequence, so that the gas enters the rest gas bags in sequence to finish sampling.

Preferably, an exhaust opening and closing device for opening or closing the exhaust opening is disposed at the other end of the main pipe, and the step S3 includes the following specific steps: closing the inlet switch device and opening the exhaust switch device at the same time, and exhausting the gas in the air bag from the exhaust port; and during step S2, the inlet switch device is turned on and the exhaust switch device is turned off.

Preferably, the sampling pipe is provided with a first electric heating device, and the first electric heating devices are all started to heat the sampling gas in the gas replacement and sampling processes, wherein the heating temperature is 120 +/-5 ℃.

Preferably, in the sampling process, a constant temperature device is arranged in the placing chamber, so that the heated gas enters the gas bag and is subjected to constant temperature treatment, and the second electric heating device is adopted as the heat preservation device.

Preferably, the placing chamber is internally divided into a multilayer structure, the chamber wall of the placing chamber comprises an outer chamber wall, an inner chamber wall and a heat insulation layer arranged between the outer chamber wall and the inner chamber wall, the second electric heating device is arranged in the heat insulation layer, so that the air bag is prevented from being in direct contact with the second heating device, a temperature sensor is arranged in the placing chamber and is used for detecting the heating temperature, and in step S6, after the air bag expands and contacts with the inner chamber wall, the second electric heating device is started to store the gas in the air bag at a constant temperature.

Preferably, a filtering device is arranged at the joint of the sampling pipe and the header pipe, the filtering device comprises a titanium filter element and a molecular sieve, and during the air inlet process of the sampling pipe, water vapor and particle impurities in the air are filtered.

Preferably, in the gas replacement and sampling processes, the sub-switching devices are all electromagnetic valves, and the electromagnetic valves are used for controlling the on-off of the electromagnetic valves through current to carry out remote control; the inlet switching device adopts an adjusting valve, and plays a role of variable resistance in a pipeline to adjust the size of air flow; the exhaust switch device adopts a ball valve.

After the technical scheme is adopted, the invention has the effects that: because the gas sampling method of the air pocket method, S1, the early preparation of the equipment:

s7, repeating the operation of the step S5 at the subsequent sampling time nodes in sequence, so that the gas enters the rest gas bags in sequence to finish sampling;

firstly, gas replacement is carried out, a sampling pipe is placed in a required sampling point, a branch switch device and an inlet switch device on each branch pipe are started, a pressure control device is started to carry out air suction and pressure reduction on a gas chamber, at the moment, the external pressure is greater than the internal pressure, gas enters a main pipe from the sampling pipe and then enters a gas bag of each branch pipe, after the gas bag is expanded to be in contact with the side wall of the gas chamber, the pressure control device carries out air blowing and pressurization on the gas chamber, at the moment, the internal pressure is greater than the external pressure, so that the gas is extruded from the gas bag, collected to the main pipe by the branch pipes and then discharged from the sampling pipe, the operation is repeated for multiple times to complete the replacement, and the switch devices, the inlet switch devices and the pressure control devices on the branch pipes are closed; then, starting sampling operation, heating the gas in the sampling pipe through a first electric heating device during first sampling, starting a pressure control device to perform air exhaust and pressure reduction on the gas chamber after the gas is heated to 120 degrees, only starting one of the branch switch devices and the inlet switch device at the moment, enabling the sampling gas to enter the main pipe from the sampling pipe, then closing the corresponding branch switch device in the opened gas bag of the branch pipe, waiting for second sampling, and only starting the other branch switch device after the operation is the same as the above, so that the gas for the second sampling enters the other gas bag until the gas bag in the device is completely collected or the required sampling times are completed; the method can acquire the gas for multiple times at one time and in different periods, realizes the replacement of the gas in the gas bag and the sampling pipe, effectively reduces the factors influencing the result, and improves the sampling efficiency.

In addition, since the other end of the main pipe is provided with the exhaust port, and the exhaust port is provided with an exhaust switch device for opening or closing the exhaust port, in the step S3, the specific flow of the air bag being squeezed to exhaust is as follows: closing the inlet switch device and opening the exhaust switch device at the same time, and exhausting the gas in the air bag from the exhaust port; in the process of step S2, the inlet switch device is turned on and the exhaust switch device is turned off, so that the gas inlet and gas outlet can be distinguished, thereby ensuring higher purity of the displaced gas and improving sampling accuracy.

And because the sampling pipe is provided with the first electric heating device, the first electric heating devices are started to heat the sampled gas in the gas replacement and sampling processes, the heating temperature is 120 +/-5 ℃, so that the moisture in the gas is evaporated, the gas dryness is improved, the dissolution of a target detection substance is reduced, and the sampling accuracy is improved.

In the sampling process, the method arranges a constant temperature device in the chamber to make the heated gas enter the air bag and then perform constant temperature treatment, the heat preservation device adopts a second electric heating device, the placing cavity is internally divided into a multi-layer structure, the chamber wall of the placing cavity comprises an outer chamber wall, an inner chamber wall and a heat preservation layer arranged between the outer chamber wall and the inner chamber wall, the second electric heating device is arranged in the heat-insulating layer, so that the air bag is prevented from being directly contacted with the second heating device, a temperature sensor is arranged in the placing cavity and is used for detecting the heating temperature, in step S6, after the air bag expands and contacts the inner chamber wall, the second electric heater starts to store the gas in the air bag at a constant temperature, therefore, the heated gas can keep the temperature all the time after entering the air bag, so that the gas can not cool condensed water drops, and the accuracy of subsequent detection is improved.

And because the connecting part of the sampling pipe and the header pipe is provided with the filtering device, the filtering device comprises the titanium filter element and the molecular sieve, in the gas inlet process of the sampling pipe, water vapor and particle impurities in the gas are filtered, the target detection substances in the gas are prevented from being dissolved by liquid water, and the detection accuracy is ensured.

In the gas replacement and sampling processes, the branch switch devices are all electromagnetic valves, the electromagnetic valves are used for controlling the on-off of the electromagnetic valves through current to carry out remote control, and the inlet switch device adopts an adjusting valve and plays a role of variable resistance in a pipeline to adjust the size of gas flow; the exhaust switch device adopts a ball valve, so that the operation is convenient and fast, and the sampling efficiency is improved.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

in the drawings: 1. a sampling box; 2. a box body; 3. a cover plate; 4. a sealing strip; 5. an air chamber; 6. placing a chamber; 61. an outer chamber wall; 62. an inner chamber wall; 63. a heat-insulating layer; 64. a second electric heating device; 7. an air bag; 8. hollowing out holes; 9. pipe distribution; 10. a first solenoid valve; 11. a second solenoid valve; 12. a third electromagnetic valve; 13. a fourth solenoid valve; 14. a main pipe; 15. an exhaust port; 16. An exhaust switch device; 17. a sampling tube; 18. an inlet opening and closing device; 19. a first electric heating device; 20. a filtration device; 21. an electric air pump; 22. a pressure gauge; 23. buckle structure

Detailed Description

The present invention is described in further detail below with reference to specific examples.

As shown in fig. 1, an air bag method gas sampling method,

s1, preparing equipment in the early stage:

s11, an air bag method gas sampling device, which comprises a sampling box 1, wherein an air chamber 5 and a placing cavity are arranged in the sampling box 1, an air bag 7 is placed in the placing cavity, the placing cavity comprises a plurality of placing cavities 6, hollow holes 8 communicated with the air chamber 5 are formed in the plurality of placing cavities 6, the air chamber 5 is connected with a pressure control device for pressurization or decompression, one air bag 7 is placed in each placing cavity 6, an inlet of the air bag 7 is fixed at the upper end of the placing cavity, an inlet of the air bag 7 is connected with a branch pipe 9, the branch pipe 9 is connected with a sampling pipe 17 through a main pipe 14, a branch switch device for opening or closing the branch pipe 9 is arranged on each branch pipe 9, an inlet switch device 18 for opening or closing is arranged between the main pipe 14 and the sampling pipe 17, and a first electric heating device 19 for heating sampling gas is arranged on the sampling pipe 17, a sampling pipe 17 of the gas sampling device is arranged at a sampling point;

s2, starting the pressure control device to exhaust the air chamber 5, starting the branch switch device and the inlet switch device 18 on each branch pipe 9, enabling the sample gas to enter each air bag 7 after passing through the sampling pipe 17, the main pipe 14 and each branch pipe 9 in sequence, and stopping the exhaust of the pressure control device after the volume expansion of each air bag 7 is contacted with the side wall of the air chamber 5;

s3, the pressure control device switches the working state to supply air and pressurize the air chamber 5, and the air bag 7 is extruded and exhausted;

s4, repeating the steps S2 to S3 for a plurality of times until the gas in the gas bag 7 is replaced;

s5, when the first sampling time is reached, opening the inlet switch device 18 and a branch switch device on one branch pipe 9, opening the pressure control device to exhaust the air chamber 5, enabling the sampled gas to enter the corresponding air bag 7, after the volume expansion of the air bag 7 is contacted with the side wall of the air chamber 5, closing the branch switch device on the branch pipe 9, stopping the air exhaust by the pressure control device, and waiting for the next sampling time;

s6, when the second sampling time is reached, repeating step S5 to make the sampled gas enter the second air bag 7;

and S7, repeating the operation of the step S5 at the subsequent sampling time nodes in sequence, so that the gas enters the rest air bags 7 in sequence to finish sampling.

An exhaust port 15 is provided at the other end of the main pipe 14, an exhaust switch device 16 for opening or closing the exhaust port 15 is provided at the exhaust port 15, and in step S3, the specific process of squeezing and exhausting the airbag 7 includes: closing the inlet opening and closing device 18 and opening the exhaust opening and closing device 16, and exhausting the gas in the gas bag 7 from the exhaust port 15; in step S2, the inlet switch 18 is turned on and the exhaust switch 16 is turned off, so that the gas in the airbag 7 is exhausted completely during the exhaust process, and the replaced gas has higher purity and more accurate sampling.

Preferably, the sampling pipe 17 is provided with a first electric heating device 19, and in the gas replacement and sampling processes, the first electric heating device 19 is started to heat the sampling gas, the heating temperature is 120 ℃ +/-5 ℃, so that the moisture of the gas entering the gas bag 7 is reduced.

In the sampling process, a constant temperature device is arranged in the placing cavity 6, so that the heated gas enters the air bag 7 and is subjected to constant temperature treatment, the second electric heating device 64 is adopted as the heat preservation device and is matched with the first electric heating device 19 for use, the gas cannot be cooled to condense water drops, the target detection substance in the gas cannot be dissolved in water, and the subsequent detection is accurate.

Preferably, the placing chamber 6 is internally divided into a multi-layer structure, the chamber wall of the placing chamber 6 comprises an outer chamber wall 61, an inner chamber wall 62 and a heat insulation layer 63 arranged between the outer chamber wall 61 and the inner chamber wall 62, the second electric heating device 64 is arranged in the heat insulation layer 63, so that the air bag 7 is prevented from being in direct contact with the second heating device, a temperature sensor is arranged in the placing chamber 6 and used for detecting the heating temperature, in step S6, after the air bag 7 expands and contacts with the inner chamber wall 62, the second electric heating device 64 is started to store the gas in the air bag 7 at a constant temperature, the multi-layer structure is adopted to slow the heat dissipation in the placing chamber 6, and the second heating device is placed in the heat insulation layer 63, so that the direct contact with the air bag 7 is avoided, and the safety is improved.

A filtering device 20 is arranged at the joint of the sampling pipe 17 and the header pipe 14, the filtering device 20 comprises a titanium filter element and a molecular sieve, and water vapor and particle impurities in gas are filtered in the gas inlet process of the sampling pipe 17; in steps S2 and S5, the gas enters the sampling tube 17 and passes through the titanium filter core and the molecular sieve, and the moisture or impurities in the gas are filtered through the titanium filter core and the molecular sieve, so that the gas purity is higher.

In the gas replacement and sampling processes, the branch switch devices are all electromagnetic valves, the electromagnetic valves are used for controlling the on-off of the electromagnetic valves through current to carry out remote control, and the inlet switch device 18 adopts an adjusting valve and plays a role of variable resistance in a pipeline to adjust the size of gas flow; the exhaust switch device 16 is a ball valve.

In addition, the embodiment of the invention also discloses a sampling device for realizing the gas sampling method by the air bag feeding method, as shown in fig. 1, the gas sampling device by the air bag method comprises a sampling box 1, an air chamber 5 and a placing cavity are arranged in the sampling box 1, the air bag 7 is placed in the placing cavity, the placing cavity comprises a plurality of placing cavities 6, hollow holes 8 communicated with the air chamber 5 are arranged on the placing cavities 6, the air chamber 5 is connected with a pressure control device for pressurization or depressurization, one air bag 7 is placed in each placing cavity 6, the inlet of the air bag 7 is fixed at the upper end of the placing cavity, the inlet of the air bag 7 is connected with a branch pipe 9, the branch pipe 9 is connected with a sampling pipe 17 through a main pipe 14, and each branch pipe 9 is provided with a branch switch device for opening or closing the branch pipe 9, an inlet switch device 18 which is opened or closed is arranged between the main pipe 14 and the sampling pipe 17, and a first electric heating device 19 which heats the sampling gas is arranged on the sampling pipe 17.

In this embodiment, the placing cavity is internally provided with 4 air bags 7, so the placing cavity comprises 4 placing cavities 6, the 4 placing cavities 6 correspond to the 4 branch pipes 9, the pressure control device is an electric air pump 21, the electric air pump 21 is connected to the air chamber 5 through an air passage pipeline, the electric air pump 21 is provided with a pressure gauge 22 convenient for observing pressure, the electric air pump 21 can continuously pump air or blow air through electric power, so that the pressure in the air chamber 5 is reduced or increased, and the pressure gauge 22 on the electric air pump 21 can observe the pressure at the moment to determine subsequent operation, thereby improving safety; the first heating device adopts an electric heating wire, the electric heating wire is arranged in the sampling pipe 17, gas in the pipe is heated, the temperature is 120 +/-5 ℃, and water vapor in the pipe is effectively reduced; the inlet switch device 18 adopts a regulating valve which has the function of variable resistance in a pipeline, so that the size of the air flow can be regulated, and the flow rate of the air flowing in and out can be effectively controlled; of course, a valve such as a ball valve or a butterfly valve which can be controlled to open and close can be used.

Further sampling box 1 includes box 2 and apron 3, connect through buckle structure 23 between apron 3 and the box 2, be provided with sealing strip 4 between apron 3 and the box 2, buckle structure 23 is current structure, therefore not in the text detailed description, 4 place cavity 6 and set up between box 2 and apron 3, air chamber 5 sets up in the below of placing cavity 6, be equipped with on the apron 3 with 4 air pocket 7 entry one-to-ones apron 3 openings and with be connected in branch pipe 9, divide switching device to adopt the solenoid valve, the solenoid valve includes first solenoid valve 10, second solenoid valve 11, third solenoid valve 12 and fourth solenoid valve 13, just so can realize the switch of air pocket 7 through every solenoid valve of circuit remote control, raise the efficiency.

In the embodiment, the other end of the main pipe 14 is provided with an exhaust port 15, the exhaust port 15 is provided with an exhaust switch device 16 for opening or closing the exhaust port 15, the collecting pipe needs to be extended far, and then the main pipe 14 is connected so that gas is not exhausted from the pipeline when gas is replaced and is drawn back into the gas bag 7, so that the gas is impure, the exhaust port 15 is arranged at the other end of the main pipe 14, the exhaust port 15 is close to the position passing through the gas bag 7, when gas is replaced, the exhaust switch device 16 is closed when the gas bag 7 inhales, the gas enters the main pipe 14 from the sampling pipe 17 and enters the gas bag 7, and when the gas bag 7 exhausts, the exhaust switch device 16 is opened, the inlet switch device 18 is closed, and the gas is exhausted from the exhaust port 15; in the sampling process, the exhaust switch device 16 is in a closed state, the exhaust switch device 16 adopts a ball valve, and gas needs to be exhausted as soon as possible when the device exhausts, so that the flow rate does not need to be controlled, and the gas enters the gas bag 7 from the main pipe 14 and is exhausted from the exhaust port 15, so that the replacement purity of the gas bag 7 is ensured, and the detection accuracy is improved.

Further, a constant temperature device for insulating the air bag 7 is further arranged on the chamber wall of the placing chamber 6, the chamber wall of the placing chamber 6 is of a multilayer structure, the chamber wall of the placing chamber 6 comprises an outer chamber wall 61, an inner chamber wall 62 and an insulating layer 63 arranged on the outer chamber wall 61 and the inner chamber wall 62, the constant temperature device is a second electric heating device 64 arranged in the insulating layer 63, a temperature sensor is arranged in the placing chamber 6, the multilayer structure is adopted to effectively reduce heat dissipation, potential safety hazards caused by direct contact between the air bag 7 and the second electric heating device 64 in the air suction expansion process of the air bag 7 are avoided, the second electric heating device 64 also adopts an electric heating wire, and after the air enters the air bag 7, the air is heated by the second heating device to avoid condensation of the air in the storage process, and subsequent detection is influenced.

Be equipped with the filter equipment 20 who is used for absorbing steam behind the entry switching device 18, filter equipment 20 includes titanium filter core and molecular sieve, the molecular sieve is the material that has the hole of even size, and these pore sizes are similar with chemical micromolecule in, therefore the macromolecule can not get into the molecular sieve or be adsorbed, and the micromolecule can, titanium filter core is formed by titanium metal sintering, has fine filtering quality, and titanium filter core has advantages such as long service life, high temperature resistant, separation efficiency height, consequently can effectively dry the moisture in the air current and filter tiny particulate matter, guarantees the degree of dryness of air current, reduces the disappearance of the target detection material that dissolves in water, makes the testing result accurate.

The working principle of the invention is as follows: firstly, replacing gas in 4 air bags 7, placing sampling pipes 17 in sampling points, starting all electromagnetic valves and inlet switch devices 18, opening an electric air pump 21, pumping air to the air chamber 5 for decompression, communicating the air chamber 5 with a placing chamber 6 through a hollow hole 8, enabling the air pressure in the air chamber 5 to be smaller than the external air pressure, pumping the gas into a main pipe 14 from the sampling pipes 17, then entering each branch pipe 9 connected with the main pipe 14, finally entering the air bags 7 to expand the air bags 7, closing the inlet switch devices 18 when the 4 air bags 7 are in contact with an inner chamber wall 62, enabling the electric air pump 21 to blow and pressurize the air chambers 5, enabling the internal air pressure in the air bags 7 to be larger than the external air pressure, extruding the gas in the air bags 7 to enter the respective branch pipes 9, starting exhaust switch devices 16, exhausting the gas from an exhaust port 15, repeating for several times, and finally exhausting the gas from the air bags 7, and (3) closing the exhaust switch device 16, all the electromagnetic valves and the electric air pump 21, starting the first electromagnetic valve 10 and the inlet switch device 18 after the first sampling time is reached, starting the electric air pump 21 to pump air and reduce pressure of the air chamber 5, enabling the air to enter the main pipe 14 from the sampling pipe 17 and then enter the branch pipe 9 for starting the first electromagnetic valve 10, finally entering the air bag 7, waiting for the air bag 7 to expand to be in contact with the inner layer chamber wall 62, closing the first electromagnetic valve 10, finishing the first sampling, and then sequentially waiting for repeating the sampling operation at the next subsequent sampling time node, so that the air sequentially enters the remaining 3 air bags 7, and finishing the sampling.

The above-mentioned embodiments are merely descriptions of the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and various modifications and alterations made to the technical solution of the present invention without departing from the spirit of the present invention are intended to fall within the scope of the present invention defined by the claims.

Claims

1. An air bag method gas sampling method is characterized in that:

s1, early-stage preparation of equipment:

s11, a gaseous sampling device of air pocket method, including the sampling case, be provided with the air chamber in the sampling case and place the chamber, the air pocket is placed in placing the intracavity, its characterized in that: the utility model discloses a sampling device for sampling gas, including placing the chamber, place the chamber and include a plurality of chambers of placing, a plurality of fretwork holes that all are provided with on placing the chamber and communicate with the air chamber, the air chamber is connected with a pressure control device who is used for pressure boost or decompression, every is placed and all has been placed one in the chamber the air pocket, the entry of air pocket is fixed in the upper end of placing the chamber, the air pocket entry all connects a branch pipe, divide the pipe to be connected with the sampling pipe through house steward, every is provided with a branch switching device who is used for opening or closing branch pipe on dividing the pipe, be equipped with the entry switching device who opens or close between house steward and the sampling pipe, be provided with the first electric heater unit that heats sampling gas on the sampling pipe, set up this gas sampling device's sampling pipe in the sampling point.

s5, when the first sampling time is reached, opening an inlet switch device and a branch switch device on one branch pipe, opening a pressure control device to exhaust the air chamber, introducing the sampled gas into a corresponding air bag, and after the volume expansion of the air bag is contacted with the side wall of the air chamber, after closing the branch switch device on the branch pipe, stopping exhausting by the pressure control device, and waiting for the next sampling time;

2. An air bag method gas sampling method according to claim 1, wherein: an exhaust opening and closing device for opening or closing the exhaust opening is arranged at the exhaust opening, and in the step S3, the specific flow of the air bag being squeezed to exhaust is as follows: closing the inlet switch device and opening the exhaust switch device at the same time, and exhausting the gas in the air bag from the exhaust port; and during step S2, the inlet switch device is turned on and the exhaust switch device is turned off.

3. An air bag method gas sampling method according to claim 2, characterized in that: be provided with first electric heater unit on the sampling pipe, at the in-process of gas replacement and sampling, first electric heater unit all starts to heat sampling gas, and heating temperature is 120 ℃ +/-5 ℃.

4. An air bag gas sampling method as defined in claim 3, wherein: in the sampling process, a constant temperature device is arranged in the placing cavity, so that the heated gas enters the air bag and is subjected to constant temperature treatment, and the second electric heating device is adopted as the heat preservation device.

5. An air bag gas sampling method as defined in claim 4, wherein: the air bag storage chamber is characterized in that the placing chamber is internally divided into a multilayer structure, the chamber wall of the placing chamber comprises an outer chamber wall, an inner chamber wall and a heat insulation layer arranged between the outer chamber wall and the inner chamber wall, the second electric heating device is arranged in the heat insulation layer, the air bag is prevented from being in direct contact with the second heating device, a temperature sensor used for detecting the heating temperature is arranged in the placing chamber, and in step S6, after the air bag expands to be in contact with the inner chamber wall, the second electric heating device is started to store the gas in the air bag at a constant temperature.

6. An air bag gas sampling method as defined in claim 5, wherein: a filtering device is arranged at the joint of the sampling pipe and the header pipe, the filtering device comprises a titanium filter element and a molecular sieve, and in the gas inlet process of the sampling pipe, water vapor and particle impurities in gas are filtered.

7. An air bag method gas sampling method according to claim 6, wherein: in the gas replacement and sampling processes, the branch switch devices are all electromagnetic valves, the electromagnetic valves are used for controlling the on-off of the electromagnetic valves through current to carry out remote control, and the inlet switch device adopts an adjusting valve and plays a role of variable resistance in a pipeline to adjust the size of gas flow; the exhaust switch device adopts a ball valve.