A constant pressure gas sampler and a control method thereof

Abstract

The present application belongs to the field of gas component detection, and discloses a gas sampler for constant-pressure gas delivery and a control method thereof. Compared with the prior art, the gas sampler can improve the sample cooling, quantification and constant-pressure delivery of the gas source, can include dehydration, is simple and easy to use, has good versatility, can automatically operate, and reduces the operation cost. The gas sampler can control the temperature, pressure and sampling volume of the pipeline gas or reactor gas with different temperatures and pressures in a large range, provide the gas sample meeting the direct use for the detector, adapt to the gas sampling device in various application occasions, especially meet the automatic sampling tool for SOFC development and product evaluation, and be used for the evaluation of raw materials, desulfurization, reforming, power generation, combustion and the like. The automatic processing of the sample can greatly improve the processing speed and reduce the personnel occupation, and improve the deficiencies of the prior art in small gas source processing, automation and versatility.

Description

Technical Field

[0001] This invention belongs to the field of gas composition detection, specifically relating to a sampler and its control method for automatically sampling and processing high-temperature gas samples and delivering them to a detector at constant pressure and quantity via a sample pipeline. Background Technology

[0002] For the analysis of gas samples in high-pressure pipelines or high-pressure containers, especially for gas samples in many reaction devices, it is necessary to obtain and send them for testing and analysis quickly. In particular, many applications require long-term continuous monitoring of sample gas, so it is desirable for the device to automatically complete the cooling, pressure transformation and quantitative delivery processes. Some devices also have dehumidification or other requirements. The device should have the characteristic of not requiring continuous human intervention.

[0003] Taking SOFCs using natural gas reforming as an example, the gas sample to be tested is obtained from the reformer, dehydrated or not, and processed into a gas sample at a conventional temperature and specified pressure. The gas composition can be detected using one or more instruments such as FID, TCD, and FPD. Gas detection mainly includes multiple basic reaction processes such as gas feedstocks, desulfurization products, products from each stage of reforming hydrogen production, products from low-temperature or high-temperature power generation, and tail gas combustion (including catalytic combustion). Specifically, it includes sulfur content, methane, ethane, other alkanes and alkenes, carbon monoxide, carbon dioxide, nitrogen, oxygen, hydrogen, and water. Technical evaluations of the degree of reaction and catalyst activity are required. Compositional analysis of feedstocks and products is performed, including on-site online and offline analysis. The gas volume is within the standard gas sample bag size, used for various requirements, such as multiple detections and storage. The volume to be processed exceeds the volume of a typical quantitative loop. Therefore, rapid, effective, and controllable processing of gases, especially high-temperature gases, is needed before delivery to the detector, including sample collection and preservation. These pretreatments typically involve adjusting the temperature to room temperature, changing the pressure to a constant pressure, such as 0.4 MPa, and quantifying the gas volume according to standard conditions, such as 100 mL, 200 mL, or 500 mL, for quantitative detection or sample retention. After delivery to the chromatograph, a specified portion is used for further quantification, such as 10 μL, 100 μL, or 1 mL, depending on the detector's settings. For trace substance analysis, enrichment is often employed. For example, after quantification, 100 mL of gas sample is adsorbed and desorbed into 1 mL, resulting in a 100-fold enrichment, which improves the detection capability of trace components. Therefore, the quantification of gas samples has clear significance.

[0004] Automatic sampling technologies that address the aforementioned characteristics are currently lacking, and known application technologies have shortcomings.

[0005] For example, patent CN102937627B describes an online preliminary separation column that removes most of the hydrogen from the hydrogen-producing mixture, while the remaining gas enters the analytical instrument. This method is not designed for full-component analysis or retention methods and functions similarly to the enrichment method of an adsorption column.

[0006] CN107957359B provides a gas sampling device for a reaction process, which is particularly suitable for high-pressure gas depressurization sampling. However, it is not suitable for gas source pressures lower than the requirements of chromatographic inlet gas, and it lacks system purging and cleaning capabilities.

[0007] CN203688323U discloses an automated gas analysis system suitable for high-flow-rate gas sources, as sampling low-flow-rate gas sources will cause significant fluctuations in flow rate and pressure.

[0008] Patent CN103454362B describes a type of technology that uses a piston cylinder. It requires high precision, makes it difficult to clean the inner wall adsorption, and may easily lead to air leakage problems.

[0009] The above-mentioned technologies still need improvement in areas such as pressure adjustment and constant pressure / quantity delivery of high-temperature pressurized gas sources, and cleaning of internal wall contaminants. Summary of the Invention

[0010] To address the above shortcomings, this invention provides a gas sampler with constant pressure gas delivery and its control method.

[0011] The above-mentioned objective of this invention is achieved through the following technical solution:

[0012] A gas sampler with constant pressure delivery includes a metering and delivery unit, a sampling and processing unit, a gas purging unit, and a system controller.

[0013] The metering and delivery unit includes a pressurized gas source, a pressurized filter, a pressure reducing valve, a pressurized pressure gauge, a pressurized valve, and a flow restrictor B connected sequentially on the pipeline, which are connected to a pressurized tank. The pressurized tank is equipped with a gas storage bag.

[0014] The pressurization tank is also connected to an air vent valve B, a meter, and a five-way valve. The meter is connected from the pressurization tank and is connected to the metering valve, the meter, and the displacement detector in sequence. The common position of the five-way valve is connected to the air storage bag.

[0015] The sampling and processing unit consists of a raw material pressure gauge, a raw material inlet thermometer, a raw material valve, a filter, a flow restrictor A, a cooler, and a distributor connected in sequence on the pipeline. The distributor is also equipped with an air vent valve A. A raw material inlet heat tracing device is provided between the raw material valve and the raw material gas source 5.

[0016] The gas purging unit's pipeline is sequentially connected to a purging gas source, a purging filter, and a purging pressure gauge. It is then divided into two paths: one for purging valve A and the other for purging valve B. The purging valve A path consists of purging valve A and flow restrictor C connected sequentially on the pipeline, which are connected to the pipeline between the gas storage bag and the five-way valve. The purging valve B path consists of purging valve B connected on the pipeline, which are connected to the pipeline between the raw material valve and the filter.

[0017] The raw material inlet heat tracing device, raw material inlet temperature sensor, raw material pressure gauge, cooler, vent valve A, five-way valve, displacement detector, vent valve B, gas storage pressure gauge, booster valve, booster pressure gauge, purge valve A and purge valve B are respectively connected to the system controller circuit.

[0018] Furthermore, the pressurization tank is a pressure-resistant, quick-opening container.

[0019] Furthermore, the metering device is a gas volume flow meter, which can be any one of a cylinder, a wet float, or a corrugated expander, preferably a wet float.

[0020] Preferably, the five-way valve is provided with a chromatographic position, a manual position, a common position, a gas sampling position, and a closed position in a clockwise direction, and the manual position is provided with a manual sampling valve.

[0021] Preferably, the flow restrictors A, B, and C use needle valves or capillary tubes to limit the gas flow rate.

[0022] Furthermore, the pressure of the booster gas source is higher than the delivery pressure specified for the target chromatograph.

[0023] Furthermore, the pressure of the booster gas source is greater than the pressure of the purge gas source.

[0024] Based on the above sampler, the automatic sample control method is as follows:

[0025] A method for controlling constant pressure gas delivery includes the following steps:

[0026] Step S1: Start Resetting

[0027] (1) The default state is that the manual sampling valve is in the closed position, the five-way valve is in the manual position, and other automatic valves are in the normally closed position.

[0028] (2) Open the vent valve A and the five-way valve to the gas intake position, open the pressure valve, squeeze the gas in the gas storage bag, and release it through the five-way valve, the liquid separator, and the vent valve A;

[0029] (3) Close the drain valve A, close the booster valve, and open the drain valve B to drain the booster tank;

[0030] (4) Open the metering valve and zero the meter;

[0031] (5) Close the metering valve and the vent valve B, and the zeroing adjustment is complete;

[0032] Step S2: Purge

[0033] (1) Open the vent valve A, set the five-way valve to the gas intake position, open the pressure valve, and complete the pressurization of the pressure tank and the exhaust of the gas storage bag;

[0034] (2) Open purge valve A and close pressure valve, and purge from purge valve A to five-way valve, separator and drain valve A along the way;

[0035] (3) Set the five-way valve to the manual position, open the manual sampling valve, close the manual sampling valve, and purge the manual sampling valve circuit;

[0036] (4) Adjust the inlet valve of the external chromatographic instrument to the vent position;

[0037] (5) Set the five-way valve to the chromatographic position and purge the gas path to the chromatogram;

[0038] (6) Set the five-way valve to manual position;

[0039] (7) Adjust the inlet valve of the external chromatographic instrument to the inlet preparation position;

[0040] (8) Close purge valve A and set the five-way valve to the gas intake position. Purge valve A to the five-way valve, separator and drain valve A along the way to release air.

[0041] (9) Set the five-way valve to manual position;

[0042] (10) Open purge valve B and purge along the path from purge valve B to cooler, distributor and drain valve A;

[0043] (11) Close purge valve B and vent valve A;

[0044] (12) Open the vent valve B to vent the pressurized tank;

[0045] (13) Open the metering valve to empty and zero the meter;

[0046] At this point, the pressurization tank can be opened to replace the air storage bag. It must be confirmed that the pressurization tank body has been restored to its closed state after the replacement is completed.

[0047] (14) Close the vent valve B. At this time, the gas storage bag is ready to receive the gas sample.

[0048] Step S3: Gas extraction

[0049] (1) Confirm that the raw material inlet temperature sensor has reached the system set temperature requirement, the cooler has reached the system set temperature requirement, and other valve positions and air pressure are under the specified conditions.

[0050] (2) Set the five-way valve to the gas position, open the metering valve, and open the raw material valve;

[0051] The raw gas passes through the raw gas valve, cooler, distributor, and five-way valve before entering the gas storage bag;

[0052] (3) The displacement detector of the meter detects the positioning trigger condition and notifies the system;

[0053] Feeding should be stopped after 10 seconds. The designed time of 10 seconds is appropriate, but it needs to be adjusted according to the actual situation.

[0054] (4) Close the raw material valve and set the five-way valve to the manual position;

[0055] Step S4: Gas delivery

[0056] (1) Close the metering valve and open the booster valve. The gas storage pressure gauge reaches the set pressure, such as a deviation of ±1kPa.

[0057] The pressure tank is scheduled to fill with air for 5-10 seconds.

[0058] (2) When the five-way valve is in the chromatographic position, the gas storage bag sends gas to the chromatograph for constant pressure and quantity; when sampling manually, the five-way valve is in the manual position.

[0059] (3) Once the external chromatography is completed, the system will send a signal to confirm the completion.

[0060] (4) Open the vent valve A, set the five-way valve to the gas intake position, vent the gas storage bag and purge the separator along with it;

[0061] Step S5: Restore

[0062] Proceed to step S2 to perform purging, in preparation for the next sampling.

[0063] The advantages of this invention compared to the prior art are:

[0064] The purpose of this invention is to provide a high-temperature gas sampler and its control method, which automatically completes the sampling, delivery, and pressure and quantity control of the pipeline to the detector and gas sample bag. Compared with the prior art, it improves the cooling, quantitative, and pressure control of the gas source sample, and can include a dehydration step. The device is simple and easy to use, has good versatility, can operate automatically, and reduces operating costs. By controlling the temperature, pressure, and sampling volume of pipeline gas or reactor gas with varying temperatures and pressures over a wide range, it provides the detector with gas samples suitable for direct use, making it a gas sampling device adaptable to various applications, especially an automatic sampling tool for SOFC development and product evaluation, used for the evaluation of raw materials, desulfurization, reforming, power generation, combustion, and other processes. Automated sample processing will greatly improve processing speed and reduce personnel requirements, overcoming the shortcomings of existing technologies in small-scale gas source processing, automation, and versatility. Attached Figure Description

[0065] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0066] Figure 1 This is a schematic diagram of the main units of the sampler;

[0067] Figure 2This is a schematic diagram showing the connection of the components of the sampler.

[0068] In the diagram: 1. Raw material valve, 2. Raw material inlet heat tracing device, 3. Raw material inlet thermometer, 4. Raw material pressure gauge, 5. Raw material gas source, 6. Filter, 7. Flow restrictor A, 8. Cooler, 9. Distributor, 10. Exhaust valve A, 11. Closed position, 12. Gas intake position, 13. Five-way valve, 14. Common position, 15. Manual position, 16. Manual sampling valve, 17. Chromatographic position, 18. Meter, 19. Displacement detector, 20. Metering valve, 21. Exhaust valve B, 22. 23. Gas storage pressure gauge, 24. Gas storage bag, 25. Pressure booster tank, 26. Flow restrictor B, 27. Flow restrictor C, 28. Pressure booster valve, 29. Pressure booster gauge, 30. Pressure reducing valve, 31. Pressure booster filter, 32. Pressure booster gas source, 33. Purge valve A, 34. Purge valve B, 35. Purge gas pressure gauge, 36. Purge filter, 37. Purge gas source, 38. System controller, 39. Quantitative and delivery unit, 40. Sampling and processing unit, 51. Gas purging unit. Detailed Implementation

[0069] The present invention is described in detail below through specific embodiments, but this does not limit the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can all be obtained commercially.

[0070] This invention uses hydrogen production detection via reforming in hydrogen fuel cells as an example, but it is not only applicable to this, but also to a wide range of conventional chemical engineering, biomedicine, environmental monitoring and other research and production control fields. It is a general gas sampling technology and is also applicable to other chemical engineering and other technical applications.

[0071] Example 1

[0072] The technical solution adopted in this invention is as follows:

[0073] See Figure 1 , Figure 2 .

[0074] A constant-pressure gas sampler comprises a metering and delivery unit 38, a sampling and processing unit 39, a gas purging unit 40, and a system controller 37. The system controller 37 controls the three main units: the metering and delivery unit 38, the sampling and processing unit 39, and the gas purging unit 40.

[0075] Figure 2 In the diagram, the outer solid line and the curved solid line with an arrow indicate that the power control output from the system controller is sent to each actuator; the outer dashed line and the curved dashed line with an arrow indicate that the signals collected by each detector are transmitted to the system controller. A single line is used for clarity and does not necessarily represent a single wire, cable, or signal line.

[0076] The quantitative delivery unit 38 consists of a pressurized gas source 31, a pressurized filter 30, a pressure reducing valve 29, a pressurized pressure gauge 28, a pressurized valve 27, and a flow restrictor B25 connected sequentially to a pressurized tank 24. The pressurized pressure refers to the delivery pressure specified for the target chromatogram within this system, achieved using the pressurized gas source 31 and pressure reducing valve 29 for gas sample delivery. The pressure of the pressurized gas source 31 must be higher than the delivery pressure specified for the target chromatogram.

[0077] The pressurization tank 24 is a pressure-resistant, quick-opening container. Inside the pressurization tank 24 is a gas storage bag 23. The pressurization tank 24 is also connected to one vent valve B21, one metering device 18, and one five-way valve 13. The vent valve B21 is directly connected to the pressurization tank 24. When the vent valve B21 is opened, the gas in the container and pipeline is depressurized to ambient pressure. One metering device 18 is connected from the pressurization tank 24. The metering device 18 is one of the gas volume flow meters, such as a cylinder, wet float, or corrugated expander, preferably a wet float. The metering device 18 has a displacement detector 19, which uses a photoelectric sensor... Limit switches and other devices obtain displacement data of continuous or specific points reached by the meter 18, which are used by the system controller 37 to calculate the gas volume data entering the meter 18 and determine the on / off conditions for gas entry; one channel of five-way valve 13, the common position 14 of the five-way valve 13 is connected to the gas storage bag 23, and the specific pipe position through the common position 14 of the five-way valve 13 is selected by the five-way valve 13, including the chromatographic position 17, manual position 15, gas sampling position 12, and closed position 11. The manual position 15 has a manual sampling valve 16. The preferred valve position adjacent order is chromatographic position 17, manual position 15, gas sampling position 12, and closed position 11.

[0078] When the pressurization tank 24 is at normal pressure and the vent valve B21 is closed, the sample gas from the sampling and processing unit inflates the gas storage bag 23. The gas in the pressurization tank 24 is squeezed into the meter 18. The displacement detector 19 transmits the expansion displacement of the meter 18 to the system controller 37. The system controller 37 obtains the amount of gas entering the gas storage bag 23 based on the displacement.

[0079] After the gas storage bag 23 is filled with gas, the metering valve 20 is closed and the pressure boosting valve 27 is opened. The pressure in the pressure boosting tank 24 increases, and the gas sample in the gas storage bag 23 is compressed. The gas is then directed through the common position 14 of the five-way valve 13.

[0080] The sampling and processing unit 39 consists of a raw material valve 1, a raw material inlet thermometer 3, a raw material pressure gauge 4, a filter 6, a flow restrictor A7, a cooler 8, and a distributor 9 connected sequentially on the pipeline. The distributor 9 also has a drain valve A10. A raw material inlet heat tracing device 2 is connected between the raw material valve 1 and the raw material gas source 5 to prevent condensable substances in the gas source from condensing at the valve inlet. Its temperature is measured by the raw material inlet thermometer 3 and transmitted to the system controller 37 for control. After the raw material valve 1 is opened, the gas from the raw material gas source 5 is filtered, cooled, and separated. Then, it passes through the gas intake position 12 of the five-way valve 13 of the metering and conveying unit, limiting the pressure tank 24 to atmospheric pressure. The drain valve B21 is closed and the metering valve 20 is opened, connecting to the gas storage bag 23 and inflating the gas storage bag 23.

[0081] The gas purging unit 40 receives gas from the purging gas source 36, which passes through the purging filter 6 and splits into two paths: purging valve A32 and purging valve B33. The purging pressure is between the booster pressure and the atmospheric pressure, with the pressure of the booster gas source 31 being greater than that of the purging gas source 36. The purging valve A32 path connects sequentially to the pipeline between the gas storage bag 23 and the five-way valve 13 via the purging valve A32 and the flow restrictor C26. When the vent valve A10 is closed, the five-way valve 13 is in the closed position 11, the pressurization tank 24 is at normal pressure, the vent valve B21 is closed, the meter 18 is vented to zero, and the gas storage bag 23 is empty, the purge valve A32 is opened, the purge gas fills the gas storage bag 23 and pressurizes the gas in the pressurization tank 24 into the meter 18. The system controller 37 obtains the amount of gas filled according to the displacement detector 19. When a certain amount is reached, the purge valve A32 is closed, the vent valve A10 is opened, the five-way valve 13 is in the gas intake position 12, the pressurization valve 27 is opened, the pressurization tank 24 is pressurized, and the gas in the gas storage bag 23 is discharged through the vent valve A10, completing the replacement and cleaning of the gas storage bag 23.

[0082] When cleaning the manual sampling valve 16 and the chromatographic line is required, open the pressure boosting valve 27 and the vent valve A32 to discharge the gas in the gas storage bag 23 through the gas intake position 12 of the five-way valve 13 and the vent valve A10. Then open the purge valve A32 to clean the pipeline from the gas storage bag 23 to the five-way valve 13 and the vent valve A10. Then the five-way valve 13 is turned to the manual position 15, and the manual sampling valve 16 can be manually opened to complete the manual position line cleaning. The five-way valve 13 is then turned to the chromatographic position 17 to purge the pipeline of the chromatographic position 17 and complete the chromatographic position 17 line cleaning.

[0083] One purge valve B33 is connected to the pipeline between raw material valve 1 and filter 6. When purge valve B33 is open, and vent valve A10 is open and the five-way valve 13 is not in the gas intake position 12, it purges filter 6, flow restrictor A7, cooler 8, liquid separator 9 to vent valve A10.

[0084] The above-mentioned flow restrictors are selected according to the gas source pressure and gas volume, and use needle valves or capillary tubes to limit the gas flow rate, so as to increase the actual usable time length for gas flow control.

[0085] Example 2

[0086] Based on the above sampler, the automatic sample control method is as follows:

[0087] Step S1: Start Resetting

[0088] (1) The default state is that the manual sampling valve 16 is in the closed position, the five-way valve 13 is in the manual position 15, and other automatic valves are in the normally closed position.

[0089] (2) Open the vent valve A10 and the five-way valve 13 to the gas intake position 12, open the pressure valve 27, squeeze the gas in the gas storage bag 23, and release the gas through the five-way valve 13, the liquid separator 9, and the vent valve A10.

[0090] (3) Close the drain valve A10, close the pressure boosting valve 27, and open the drain valve B21 to drain the pressure boosting tank 24.

[0091] (4) Open metering valve 20 and zero meter 18;

[0092] (5) Close metering valve 20 and vent valve B21. Zeroing adjustment is complete.

[0093] Step S2: Purge

[0094] (1) Open the vent valve A10, set the five-way valve 13 to the gas intake position 12, open the pressure boosting valve 27, and complete the pressurization of the pressure boosting tank 24 and the exhaust of the gas storage bag 23.

[0095] (2) Open the purge valve A32 and close the pressure booster valve 27, and purge the purge valve A32 to the five-way valve 13, the liquid separator 9, and the drain valve A10 along the path;

[0096] (3) Set the five-way valve 13 to the manual position 15, open the manual sampling valve 16, close the manual sampling valve 16, and purge the manual sampling valve 16.

[0097] (4) Adjust the inlet valve of the external chromatographic instrument to the vent position;

[0098] (5) Set the five-way valve 13 to the chromatographic position 2 and purge the gas path to the chromatograph;

[0099] (6) Set the five-way valve 13 to the manual position 15;

[0100] (7) Adjust the inlet valve of the external chromatographic instrument to the inlet preparation position;

[0101] (8) Close purge valve A32 and set five-way valve 13 to gas intake position 12. Purge valve A32 to five-way valve 13, liquid separator 9 and drain valve A10 along the path to release air.

[0102] (9) Set the five-way valve 13 to the manual position 15;

[0103] (10) Open purge valve B33 and purge along the path from purge valve B33 to cooler 8, distributor 9 and drain valve A10;

[0104] (11) Close purge valve B33 and vent valve A10;

[0105] (12) Open the vent valve B21 to vent the pressure tank 24;

[0106] (13) Open metering valve 20 and empty meter 18 to zero;

[0107] At this point, the pressurization tank 24 can be opened to replace the air storage bag 18. It must be confirmed that the tank body of the pressurization tank 24 has been restored after the replacement is completed.

[0108] (14) Close the vent valve B21. At this time, the gas storage bag 23 is ready to receive the gas sample.

[0109] Step S3: Gas extraction

[0110] (1) Confirm that the raw material inlet temperature sensor 3 has reached the system set temperature requirement, the cooler 8 has reached the system set temperature requirement, and other valve positions and air pressure are under the specified conditions.

[0111] (2) Set the five-way valve 13 to the gas intake position 12, open the metering valve 20, and open the raw material valve 1;

[0112] The raw material gas passes through raw material valve 1, cooler 8, distributor 9, and five-way valve 13 before entering the gas storage bag 23;

[0113] (3) The displacement detector 19 of the meter 18 detects the positioning trigger condition and notifies the system;

[0114] Feeding should be stopped after 10 seconds. The designed time of 10 seconds is appropriate, but it needs to be adjusted according to the actual situation.

[0115] (4) Close raw material valve 1 and set five-way valve 13 to manual position 15;

[0116] Step S4: Gas delivery

[0117] (1) Close metering valve 20, open pressure boosting valve 27, and gas storage pressure gauge 22 reaches the set pressure, such as a deviation of ±1kPa;

[0118] The pressure tank 24 is scheduled to be filled with air for 5-10 seconds.

[0119] (2) The five-way valve 13 is positioned at the chromatographic position 17, and the gas storage bag 23 supplies gas to the chromatograph at constant pressure and quantitatively. When sampling manually, the five-way valve 13 is placed in the manual position 15.

[0120] (3) Once the external chromatography is completed, the system will send a signal to confirm the completion.

[0121] (4) Open the drain valve A10, set the five-way valve 13 to the gas intake position 12, drain the gas storage bag 23 and purge the liquid separator 9.

[0122] Step S5: Restore

[0123] Proceed to step S2 to perform purging, in preparation for the next sampling.

[0124] The embodiments described above are merely preferred embodiments of the present invention, and not all feasible embodiments of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A gas sampler with constant pressure delivery, characterized in that, It includes a quantitative and delivery unit (38), a sampling and processing unit (39), a gas purging unit (40), and a system controller (37); The metering and delivery unit (38) includes a pressurized gas source (31), a pressurized filter (30), a pressure reducing valve (29), a pressurized pressure gauge (28), a pressurized valve (27), and a flow restrictor B (25) connected sequentially on the pipeline, and is connected to a pressurized tank (24), which is equipped with a gas storage bag (23). The booster tank (24) is also connected to an air vent valve B (21), a meter (18), and a five-way valve (13). The meter (18) is connected from the booster tank (24) and is connected to the metering valve (20), the meter (18), and the displacement detector (19) in sequence. The five-way valve (13) is provided with a chromatographic position (17), a manual position (15), a common position (14), a gas intake position (12), and a closed position (11) in a clockwise direction. The common position (14) of the five-way valve (13) is connected to the gas storage bag (23). The sampling and processing unit (39) consists of a raw material pressure gauge (4), a raw material inlet thermometer (3), a raw material valve (1), a filter (6), a flow restrictor A (7), a cooler (8), and a distributor (9) connected sequentially on the pipeline. The distributor (9) is also equipped with an air vent valve A (10). A raw material inlet heat tracing device (2) is provided between the raw material valve (1) and the raw material gas source (5). The gas purging unit (40) is connected in sequence to the purging gas source (36), the purging filter (35) and the purging pressure gauge (34), and then divided into one path of purging valve A (32) and one path of purging valve B (33). The purging valve A (32) path is connected to the pipeline between the gas storage bag (23) and the five-way valve (13) by the purging valve A (32) and the flow limiter C (26) connected in sequence on the pipeline; the purging valve B (33) path is connected to the pipeline between the raw material valve (1) and the filter (6) by the purging valve B (33) connected on the pipeline. Among them, the raw material port heat tracing device (2), raw material port temperature measuring device (3), raw material pressure gauge (4), cooler (8), vent valve A (10), five-way valve (13), displacement detector (19), vent valve B (21), gas storage pressure gauge (22), pressure boosting valve (27), pressure boosting gauge (28), purge valve A (32) and purge valve B (33) are respectively connected to the system controller (37) by line; The flow restrictors A (7), B (25) and C (26) use needle valves or capillaries to limit the gas flow rate.

2. A gas sampler with constant pressure gas delivery as described in claim 1, characterized in that, The pressurization tank (24) is a pressure-resistant, quick-opening container.

3. A gas sampler with constant pressure gas delivery as described in claim 1, characterized in that, The meter (18) is a gas volume flow meter.

4. A gas sampler with constant pressure gas delivery as described in claim 3, characterized in that, The meter (18) can be any one of a cylinder, a wet float, or a corrugated expander.

5. A gas sampler with constant pressure gas delivery as described in claim 1, characterized in that, The manual position (15) of the five-way valve (13) is equipped with a manual sampling valve (16).

6. A gas sampler with constant pressure gas delivery as described in claim 1, characterized in that, The pressure of the booster gas source (31) is higher than the delivery pressure specified for the target chromatogram.

7. A gas sampler with constant pressure gas delivery as described in claim 1, characterized in that, The pressure of the booster gas source (31) is greater than the pressure of the purge gas source (36).

8. A method for controlling constant-pressure gas delivery, characterized in that, The gas sampler with constant pressure gas delivery as described in claim 1 includes the following steps: Step S1: Start Resetting a. The default state is that the manual sampling valve (16) is in the closed position, the five-way valve (13) is in the manual position (15), and other automatic valves are in the normally closed position; b. Open the vent valve A (10) and the five-way valve (13) to the gas intake position (12), open the pressure boosting valve (27) to squeeze the gas in the gas storage bag (23) and release it through the five-way valve (13), the liquid separator (9) and the vent valve A (10); c. Close the drain valve A (10), close the booster valve (27), and open the drain valve B (21) to drain the booster tank (24); d. Open the metering valve (20) and zero the meter (18); e. Close the metering valve (20) and the vent valve B (21) to complete the zeroing adjustment; Step S2: Purge a. Open the vent valve A (10), set the five-way valve (13) to the gas intake position (12), open the pressure boosting valve (27), and complete the pressurization of the pressure boosting tank (24) and the exhaust of the gas storage bag (23); b. Open purge valve A (32) and close pressure valve (27), and purge purge valve A (32) to five-way valve (13), separator (9) and drain valve A (10) along the path; c. Set the five-way valve (13) to the manual position (15), open the manual sampling valve (16), close the manual sampling valve (16), and purge the manual sampling valve (16) path; d. Adjust the inlet valve of any external chromatographic instrument to the vent position; e. Set the five-way valve (13) to the chromatographic position (17) and purge the gas path to the chromatograph; f. Set the five-way valve (13) to the manual position (15); g. Adjust the inlet valve position of the external chromatographic instrument (outside this device) to be ready for inlet; h. Close purge valve A (32), set five-way valve (13) to gas intake position (12), and vent along the path from purge valve A (32) to five-way valve (13), separator (9), and vent valve A (10); i. Set the five-way valve (13) to the manual position (15); j. Open purge valve B (33) and purge along the path from purge valve B (33) to cooler (8), distributor (9) and drain valve A (10); k. Close purge valve B (33) and vent valve A (10); l. Open the vent valve B (21) to vent the pressurized tank (24); m. Open the metering valve (20) and empty the meter (18) to zero; n. Close the vent valve B (21), at which point the gas storage bag (23) is ready to receive the gas sample; Step S3: Gas extraction a. Confirm that the raw material inlet temperature sensor (3) has reached the system-set temperature requirement, the cooler (8) has reached the system-set temperature requirement, and other valve positions and air pressure are already under the specified conditions; b. Set the five-way valve (13) to the gas intake position (12), open the metering valve (20), and open the raw material valve (1); the raw material gas passes through the raw material valve (1), cooler (8), separator (9), and five-way valve (13) and enters the gas storage bag (23). c. The displacement detector (19) of the meter (18) detects the positioning trigger condition and notifies the system; the feeding stops after 10 seconds. d. Close the raw material valve (1) and set the five-way valve (13) to the manual position (15); Step S4: Gas delivery a. Close the metering valve (20), open the booster valve (27), and the gas storage pressure gauge (22) reaches the set pressure; the booster tank (24) is scheduled to fill for 5~10 seconds; b. The five-way valve (13) is positioned at the chromatographic position (17), and the gas storage bag (23) supplies gas to the chromatograph for constant pressure and quantitative sampling. When sampling manually, the five-way valve (13) is placed in the manual position (15). c. Once the external chromatography is complete, the system sends a signal to confirm the completion. d. Open the vent valve A (10), place the five-way valve (13) in the gas intake position (12), vent the gas storage bag (23) and purge the separator (9); Step S5: Restore Proceed to step S2 to perform purging, in preparation for the next sampling.

9. The constant pressure gas delivery control method as described in claim 8, characterized in that, In step S4a, the gas storage pressure gauge (22) reaches the set pressure with a deviation of ±1 kPa.

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