Inert gas sample carrier gas replacement device and method

Abstract

The application discloses an inert gas sample carrier gas replacement device and method, which solves the technical problems of large equipment, huge energy consumption and unsuitability for laboratory small sample processing in the existing inert gas enrichment and concentration method. The inert gas sample carrier gas replacement device comprises a water removal device, a first purification column, a circulating pump, a second purification column and a variable volume container connected in sequence through pipelines, and a vacuum pump, a pressure sensor, a target carrier gas bottle and two heating furnaces. One end of the water removal device is connected with a gas sample source through a first valve, and the other end is connected with the inlet of the first purification column in sequence through a second valve and a third valve. The gas sample source is used for filling sample gas into the pipeline. The variable volume container is compressed or stretched to cooperate with the circulating pump, so as to drive the sample gas in the pipeline to be transported back and forth between the first purification column and the second purification column. The two heating furnaces are used for heating the first purification column and the second purification column, and the carrier gas in the inert gas sample is replaced.

Description

Technical Field

[0001] This invention relates to a carrier gas replacement device and method, specifically to a carrier gas replacement device and method for an inert gas sample. Background Technology

[0002] With advancements in instrument design and the development and application of technologies, the analytical measurement accuracy of inert gas isotope ratios is increasing, leading to more stringent requirements for sample pretreatment. For example, the measurement and analysis of background Xe isotopes in the environment near nuclear power plants commonly employs instrumental analysis methods such as multi-receiver inductively coupled plasma mass spectrometry (ICP-MS) and quadrupole mass spectrometry (QMS). These methods all require pretreatment of gas samples to obtain suitable samples for measurement, reducing or eliminating interference from impurity gases and ensuring higher accuracy data during measurement. Replacing impurity gases in the gas sample with the working gas is one of the key techniques in sample pretreatment. Currently, the main methods for enriching and concentrating inert gases include cryogenic distillation, solvent adsorption, and membrane separation. Low-temperature distillation is based on the difference in boiling points of atmospheric components, using mechanical devices to compress and liquefy air for distillation. However, it has problems such as complex process, large equipment, and huge energy consumption, making it unsuitable for small sample processing in the laboratory (see CHEN LJ, REISS PS, CHONG SY, et al. Separation of rare gases and chiral molecules by selective binding in porous organic cages [J]. Nature Materials, 2014, 13(10): 954-960.). Solvent adsorption utilizes the difference in solubility of gases in the absorbing solvent to achieve absorption and separation between components of Xe gas mixtures. However, this method has problems such as complex equipment, low efficiency, and easy introduction of gases that volatilize in the solution (see Hu Bo, Zhang Xueping, Su Minggao, et al. Research status of adsorption and separation technology of 85Kr / 133Xe in radioactive gases [J]. Applied Chemical Industry, 2018, 47(9): 2010-2014.). Membrane separation uses pressure to drive gas through a porous membrane, and utilizes the differences in adsorption, diffusion and permeation rates of different rare gases in the membrane to achieve gas separation. This method is inefficient and the separation is incomplete (see Chen Zhanying, Liu Shujiang, Wang Jianlong, et al. Research on xenon-radon separation technology based on preparative gas chromatography [J]. Atomic Energy Science and Technology, 2016, 50(11): 1949-1955). Summary of the Invention

[0003] The purpose of this invention is to solve the technical problems of existing inert gas enrichment and concentration methods, which involve large equipment, huge energy consumption, and are not suitable for small sample processing in the laboratory. The invention provides a carrier gas replacement device and method for inert gas samples.

[0004] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0005] A carrier gas replacement device for an inert gas sample is characterized by comprising a water removal device, a first purification column, a circulation pump, a second purification column and a variable volume container connected in sequence by pipelines, as well as a vacuum pump, a pressure sensor, a target carrier gas bottle and two heating furnaces.

[0006] One end of the dehydration device is connected to a gas sample source via a first valve, and the other end is connected to the inlet of the first purification column via a second valve and a third valve in sequence. The gas sample source is used to fill the pipeline with sample gas.

[0007] The variable volume container is compressed or stretched to work with the circulation pump to transport the sample gas in the pipeline back and forth between the first purification column and the second purification column.

[0008] The two heating furnaces are used to heat the first purification column and the second purification column respectively, and both the first purification column and the second purification column are filled with alloy getter to purify the sample gas for replacing the carrier gas in the inert gas sample.

[0009] The vacuum pump's vacuuming end is connected to the pipeline between the second purification column and the variable volume container, and is used to evacuate the pipeline.

[0010] The outlet of the target carrier gas cylinder is connected to the pipeline between the second valve and the third valve in sequence through the fourth valve and the first tee fitting, which is used to blow the purified gas in the pipeline into the variable volume container through the target carrier gas contained in the target carrier gas cylinder.

[0011] A pressure sensor is installed at the remaining port of the first tee pipe joint to detect the pressure value inside the pipe.

[0012] Furthermore, the carrier gas replacement device in the inert gas sample also includes a first four-way pipe joint, a second three-way pipe joint, and a high-precision vacuum gauge;

[0013] The first port of the second three-way connector is connected to the vacuum pump's vacuum end via the tenth valve; the second port of the second three-way connector is connected to the first port of the first four-way connector via the eighth valve; the third port of the second three-way connector is connected to the high-precision vacuum gauge via the ninth valve; the second port of the first four-way connector is connected to the second purification column via the fifth valve; and the third port of the first four-way connector is connected to the variable volume container via the sixth valve.

[0014] The high-precision vacuum gauge is used to detect the pressure inside the pipeline.

[0015] Furthermore, the carrier gas replacement device in the inert gas sample also includes a second four-way pipe joint;

[0016] The first port of the second four-way connector is connected to the fourth port of the first four-way connector in sequence through the eleventh valve and the seventh valve. The second port of the second four-way connector is connected to the first purification column through the third valve. The third port of the second four-way connector is connected to the water removal device through the second valve. The fourth port of the second four-way connector is connected to the first port of the first three-way connector through the twelfth valve. The second port of the first three-way connector is connected to the target carrier gas cylinder through the fourth valve. The third port of the first three-way connector is connected to the pressure sensor through the thirteenth valve.

[0017] Furthermore, both the seventh and eighth valves are located at the interface positions corresponding to the first four-way pipe joint.

[0018] Furthermore, both the eleventh and twelfth valves are located at the interface positions corresponding to the second four-way pipe joint.

[0019] Meanwhile, the present invention also provides a method for carrier gas replacement in an inert gas sample, using the above-mentioned carrier gas replacement device for an inert gas sample, characterized by the following steps:

[0020] Step 1: Close the first valve and the fourth valve, and open the remaining valves, the circulation pump and the vacuum pump to evacuate the pipeline;

[0021] Step 2: Start the two heating furnaces, heat to the preset working temperature, and maintain the preset working temperature for time T until the first preset pressure is reached in the pipeline. Then stop the vacuuming and turn off the circulation pump.

[0022] Step 3: Close the third valve and open the first valve. The gas sample source fills the pipeline with sample gas. Record the initial pressure P0 in the pipeline by reading the pressure sensor.

[0023] Step 4: Open the third valve and the sample gas enters the pipeline after the third valve until the pressure sensor reading decreases at a rate of less than or equal to 10 Pa / min. Then close the second valve and the first valve.

[0024] Step 5: Turn on the circulation pump and the variable volume container. The variable volume container is compressed or stretched, and in conjunction with the circulation pump, the sample gas flows back and forth between the first and second purification columns to purify the sample gas until the pressure sensor reading no longer changes. Then, turn off the circulation pump. At the same time, when the variable volume container is stretched to its maximum volume, turn off the variable volume container so that its volume no longer changes. Return to step 3 and open the second valve until the sample gas pressure in the gas sample source drops to P1, where P0 > P1.

[0025] Step 6: Adjust the outlet pressure of the target carrier gas cylinder to P. x Open the fourth valve, and the target carrier gas will blow the purified sample gas in the pipeline into the variable volume container. The pressure sensor reading is P. x Then, close the fourth valve to complete the replacement of the carrier gas in the inert gas sample.

[0026] Furthermore, step 6 is followed by a pipe cleaning step:

[0027] Step S1: Open the eighth valve, the ninth valve, the tenth valve and the vacuum pump to evacuate the pipeline until the pipeline reaches the second preset pressure, then close the eighth valve and the vacuum pump; wherein, the second preset pressure is less than 100 Pa.

[0028] Step S2: Open the fourth valve for time T1 and then close it. Return to step S1 and repeat N times. Then close all valves, where T1 is 2s-3s and N is 3-5 times to complete the pipeline flushing.

[0029] Furthermore, in step 2, the first preset pressure is less than 10 Pa; T ≥ 20 min.

[0030] Furthermore, in step 1, opening the remaining valves also includes opening the ninth valve, the eighth valve, the fifth valve, the third valve, the twelfth valve, the thirteenth valve, the seventh valve, the eleventh valve, the tenth valve, the sixth valve, and the second valve;

[0031] Step 3 includes closing the seventh, eleventh, eighth, and ninth valves simultaneously with closing the third valve.

[0032] In step 6, after closing the fourth valve, open the eleventh and seventh valves. When the pressure sensor reading changes by less than or equal to 50 Pa, close the sixth valve.

[0033] Furthermore, in step 6, the target carrier gas in the target carrier gas cylinder is high-purity argon, or high-purity helium, or high-purity nitrogen, with a purity greater than or equal to 99.999%.

[0034] Compared with the prior art, the present invention has the following beneficial technical effects:

[0035] 1. The present invention provides a carrier gas replacement device for inert gas samples, which adopts a purification pipeline consisting of a water removal device, a first purification column, a circulation pump, a second purification column, and a variable volume container connected in series. Through the cooperation of the circulation pump and the variable volume container, the sample gas flows back and forth between the first purification column and the second purification column, thereby improving purification efficiency, reducing device size, realizing miniaturized integrated design, minimizing loss during sample gas processing, and requiring a low total amount of sample to be tested. It has a simple process, high purification efficiency, and can realize rapid pretreatment of small sample volumes, significantly improving work efficiency. It is suitable for use in the laboratory to complement precision measuring instruments and form a complete online testing system.

[0036] 2. The present invention provides a carrier gas replacement device for inert gas samples, which can meet different purification requirements of sample gases by filling the first purification column and the second purification column with different alloy getters.

[0037] 3. The present invention provides a carrier gas replacement device in an inert gas sample. By setting a seventh valve and an eleventh valve, when the pipeline is flushed with the target carrier gas after purification, it is convenient to evacuate the pipeline and detect whether the purified gas in the purification pipeline is completely filled into the variable volume container.

[0038] 4. The carrier gas replacement device in an inert gas sample provided by the present invention, by setting the eighth valve, the ninth valve, the twelfth valve and the thirteenth valve, can better protect the high-precision vacuum gauge and pressure sensor, and improve the stability and safety of the operation of the carrier gas replacement device in an inert gas sample.

[0039] 5. The present invention provides a carrier gas replacement device for an inert gas sample. By setting the seventh and eighth valves near the interface positions corresponding to the first four-way pipe joint, and setting the eleventh and twelfth valves near the interface positions corresponding to the second four-way pipe joint, more sample gas can be located in the purification pipeline, thereby improving the purification efficiency.

[0040] 6. The present invention provides a method for carrier gas replacement in inert gas samples. By setting up a water removal device, a circulating pump in conjunction with a first purification column, a second purification column, and a variable volume container, the sample gas in the pipeline flows into or out of the first and second purification columns respectively, so that the sample gas can fully contact the water removal device and the getter material in the two high-temperature purification columns to remove most of the non-inert gases. Then, an appropriate amount of high-purity target carrier gas is introduced to complete the carrier gas replacement of the inert gas sample. This method effectively solves the compatibility problem between inert gas samples and measuring instruments, improves purification efficiency, and has a simple process and high purification efficiency, making it suitable for the pretreatment of small-volume, high-precision analytical samples.

[0041] 7. The present invention provides a method for replacing carrier gas in an inert gas sample. By setting an eleventh valve and a seventh valve, it is convenient to detect whether the purified gas in the purification pipeline is completely filled into the variable volume container. If the pressure sensor reading changes outside the range, it indicates that the purification column may be sintered and blocked, blocking the purification pipeline and preventing the carrier gas from being completely filled. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of an embodiment of a carrier gas replacement device for an inert gas sample according to the present invention.

[0043] The annotations in the attached figures are explained as follows:

[0044] 1. High-precision vacuum gauge; 2. Ninth valve; 3. Second tee connector; 4. Eighth valve; 5. First four-way connector; 6. Fifth valve; 7. Heating furnace; 8. First purification column; 9. Circulation pump; 10. Third valve; 11. Second four-way connector; 12. Twelfth valve; 13. Thirteenth valve; 14. Pressure sensor; 15. Seventh valve; 16. Eleventh valve; 17. Tenth valve; 18. Sixth valve; 19. Variable volume container; 20. Second valve; 21. Dehydration device; 22. First valve; 23. Fourth valve; 24. Target carrier gas cylinder; 25. Vacuum pump; 26. Heating temperature controller; 27. Variable volume controller; 28. Gas sample source; 29. ​​Second purification column; 30. First tee connector. Detailed Implementation

[0045] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0046] like Figure 1 As shown, this embodiment provides a carrier gas replacement device for an inert gas sample, including a first valve 22, a water removal device 21, a second valve 20, a second four-way connector 11, a third valve 10, a first purification column 8, a circulation pump 9, a second purification column 29, a fifth valve 6, a first four-way connector 5, a sixth valve 18, and a variable volume container 19 connected in sequence by pipelines, as well as a vacuum pump 25, a target carrier gas bottle 24, a pressure sensor 14, two heating furnaces 7, a high-precision vacuum gauge 1, a second three-way connector 3, and a first three-way connector 30;

[0047] The inlet of the first valve 22 is used to connect to an external gas sample source 28; the circulation pump 9 is used to transport the sample gas in the pipeline back and forth between the first purification column 8 and the second purification column 29; the variable volume container 19, by compression or stretching, cooperates with the circulation pump 9 to drive the sample gas in the pipeline to flow into or out of the first purification column 8 and the second purification column 29 respectively.

[0048] Two heating furnaces 7 are used to heat the first purification column 8 and the second purification column 29 respectively. Both the first purification column 8 and the second purification column 29 are filled with alloy getter to purify the sample gas and replace the carrier gas in the inert gas sample. In this embodiment, the alloy getter is ZrVFe alloy or ZrAl alloy.

[0049] The vacuum pump 25's vacuuming end is connected to the first port of the second tee connector 3 via the tenth valve 17. The second port of the second tee connector 3 is connected to the first port of the first four-way connector 5 via the eighth valve 4. The third port of the second tee connector 3 is connected to the high-precision vacuum gauge 1 via the ninth valve 2. The second port of the first four-way connector 5 is connected to the second purification column 29 via the fifth valve 6. The third port of the first four-way connector 5 is connected to the variable volume container 19 via the sixth valve 18. The fourth port of the first four-way connector 5 is connected sequentially via the seventh valve 15 and the eleventh valve. Valve 16 is connected to the first interface of the second four-way connector 11. The second interface of the second four-way connector 11 is connected to the first purification column 8 through the third valve 10. The third interface of the second four-way connector 11 is connected to the water removal device 21 through the second valve 20. The fourth interface of the second four-way connector 11 is connected to the first interface of the first three-way connector 30 through the twelfth valve 12. The second interface of the first three-way connector 30 is connected to the target carrier gas cylinder 24 through the fourth valve 23. The third interface of the first three-way connector 30 is connected to the pressure sensor 14 through the thirteenth valve 13.

[0050] Vacuum pump 25 is used to evacuate the pipeline; the target carrier gas in target carrier gas cylinder 24 is used to blow the purified gas in the pipeline into variable volume container 19; pressure sensor 14 is used to detect the pressure value in the pipeline. High-precision vacuum gauge 1 is used to detect the pressure in the pipeline. Eleventh valve 16 and twelfth valve 12 are both located near the interface position corresponding to the second four-way connector 11, and seventh valve 15 and eighth valve 4 are both located near the interface position corresponding to the first four-way connector 5, which allows more sample gas to be located in the purification pipeline, improving purification efficiency.

[0051] Meanwhile, the present invention also provides a method for carrier gas replacement in an inert gas sample, which uses the above-mentioned carrier gas replacement device for inert gas samples and includes the following steps:

[0052] Step 1: Close the first valve 22 and the fourth valve 23, and open the remaining valves and vacuum pump 25 to evacuate the pipeline; avoid the influence of air impurities on the replacement of the carrier gas. Alternatively, when the seventh valve 15 and eleventh valve 16 pipelines are not installed, vacuuming can be achieved by turning on the circulation pump (9). When the seventh valve 15 and eleventh valve 16 pipelines are installed, vacuuming can be achieved by keeping the circulation pump (9) closed.

[0053] Step 2: Start both heating furnaces 7, heat to the preset working temperature, and maintain the preset working temperature for a time T until the first preset pressure is reached in the pipeline, then stop vacuuming. Vacuuming can be stopped by turning off the vacuum pump 25 or by closing the tenth valve 17. Maintaining the preset working temperature T allows the alloy getter to reach its working temperature, effectively removing adsorbed impurity gases from its surface during heating. In this embodiment, T ≥ 20 min, and the first preset pressure is less than 10 Pa. This value is detected by a high-precision vacuum gauge 1. The two heating furnaces 7 are independently controlled by their respective heating temperature controllers 26, with a temperature control accuracy of no more than 1°C and a temperature control range of 0°C-1000°C.

[0054] Step 3: Close valves 10 (third), 15 (seventh), 16 (eleventh), 4 (eighth), and 2 (ninth);

[0055] Step 4: Open the first valve 22 and the second valve 20, and the gas sample source 28 fills the pipeline with sample gas. The initial pressure P0 in the pipeline is recorded by the pressure sensor 14. This is convenient for subsequent calculation of purification efficiency, or for monitoring the purification status in the pipeline at any time based on the changes in the pressure sensor 14 reading.

[0056] Step 5: Open the third valve 10, and the sample gas enters the pipeline after the third valve 10 until the rate of decrease of the pressure sensor 14 reading is less than or equal to 10 Pa / min. Then close the second valve 20 and the first valve 22. When the rate of decrease of the pressure sensor 14 reading is less than or equal to 10 Pa / min, it means that the pipeline is saturated with gas and no longer needs to be diluted. It is necessary to stop filling the pipeline with sample gas.

[0057] Step 6: Turn on the circulation pump 9 and the variable volume container 19. The variable volume container 19 is compressed or stretched, and in conjunction with the circulation pump 9, the sample gas flows back and forth between the first purification column 8 and the second purification column 29 to purify the sample gas until the pressure sensor 14 reading no longer changes. Then, turn off the circulation pump 9. Simultaneously, when the variable volume container 19 is stretched to its maximum volume, turn it off to prevent further volume changes. Return to step 4 until the sample gas pressure value in the gas sample source 28 (i.e., the pressure sensor 14 reading when the first valve 22 is opened) decreases to P1, where P1 is less than P0. The purification efficiency is calculated using P0 and P1, or used to determine if the alloy getter has completely failed. This improves the sample purification rate and efficiency. In this embodiment, the variable volume container 19 is independently controlled by the variable volume controller 27. Turning off the variable volume container 19 here only prevents its volume from changing; it still allows gas to be filled in. Only closing the sixth valve 18 will stop the gas filling into the variable volume container 19.

[0058] Step 7: Adjust the outlet pressure of the target carrier gas cylinder 24 to P. x Open the fourth valve 23, and the target carrier gas blows the purified sample gas in the pipeline into the variable volume container 19. The pressure sensor 14 reads P. x Then, close the fourth valve 23, open the eleventh valve 16 and the seventh valve 15, and when the change in the pressure sensor 14 reading is less than or equal to 50 Pa, close the sixth valve 18 to complete the carrier gas replacement in the inert gas sample. Adjust the outlet pressure P... x The purified sample is diluted to different concentrations to facilitate subsequent instrument measurements. By setting the eleventh valve 16 and the seventh valve 15, after pressurization, opening the seventh valve 15 and the eleventh valve 16 can determine whether the target carrier gas has been completely filled into the variable volume container 19. If the pressure sensor 14 reading is outside the range, it indicates that the purification column may be sintered and blocked, clogging the purification pipeline and preventing the carrier gas from being completely filled into the variable volume container 19. In this case, the range of pressure sensor 14 reading is determined based on actual working experience. In this embodiment, the target carrier gas in the target carrier gas bottle 24 is high-purity argon, high-purity helium, or high-purity nitrogen, with a purity greater than or equal to 99.999%.

[0059] After replacing the carrier gas in the inert gas sample, the pipeline needs to be flushed to facilitate subsequent carrier gas replacement. The following steps are the flushing process:

[0060] Step 8: Open the eighth valve 4, the ninth valve 2, the tenth valve 17 and the vacuum pump 25 to evacuate the pipeline until the second preset pressure is reached, then close the eighth valve 4 and the vacuum pump 25; in this embodiment, the second preset pressure is less than 100 Pa.

[0061] Step 9: After opening the fourth valve 23 for time T1, close it and return to step 8. Repeat this process N times, then close all valves, where N is 3 to 5 times, to complete the pipeline flushing.

[0062] In this embodiment, P0 in step 4 and P in step 7 x All are determined based on usage requirements.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A carrier gas replacement device for an inert gas sample, characterized in that: It includes a water removal device (21), a first purification column (8), a circulation pump (9), a second purification column (29) and a variable volume container (19) connected in sequence by pipelines, as well as a vacuum pump (25), a pressure sensor (14), a target carrier gas cylinder (24) and two heating furnaces (7). One end of the dewatering device (21) is connected to a gas sample source (28) via a first valve (22), and the other end is connected to the inlet of the first purification column (8) via a second valve (20) and a third valve (10) in sequence. The gas sample source (28) is used to fill the pipeline with sample gas. The variable volume container (19) is compressed or stretched to cooperate with the circulation pump (9) to drive the sample gas in the pipeline to be transported back and forth between the first purification column (8) and the second purification column (29); The two heating furnaces (7) are used to heat the first purification column (8) and the second purification column (29) respectively, and both the first purification column (8) and the second purification column (29) are filled with alloy getter to purify the sample gas for replacing the carrier gas in the inert gas sample. The vacuum pump (25) is connected to the pipeline between the second purification column (29) and the variable volume container (19) for evacuating the pipeline; The outlet of the target carrier gas cylinder (24) is connected to the pipeline between the second valve (20) and the third valve (10) through the fourth valve (23) and the first tee pipe joint (30) in sequence. This is used to blow the purified gas in the pipeline into the variable volume container (19) through the target carrier gas contained in the target carrier gas cylinder (24). A pressure sensor (14) is provided at the remaining port of the first tee pipe joint (30) to detect the pressure value in the pipeline.

2. The carrier gas replacement device for inert gas samples according to claim 1, characterized in that: It also includes a first four-way pipe connector (5), a second three-way pipe connector (3), and a high-precision vacuum gauge (1); The first port of the second three-way connector (3) is connected to the vacuum pump (25) via the tenth valve (17), the second port of the second three-way connector (3) is connected to the first port of the first four-way connector (5) via the eighth valve (4), the third port of the second three-way connector (3) is connected to the high-precision vacuum gauge (1) via the ninth valve (2), the second port of the first four-way connector (5) is connected to the second purification column (29) via the fifth valve (6), and the third port of the first four-way connector (5) is connected to the variable volume container (19) via the sixth valve (18). The high-precision vacuum gauge (1) is used to detect the pressure inside the pipeline.

3. The carrier gas replacement device for inert gas samples according to claim 2, characterized in that: It also includes a second four-way pipe fitting (11); The first interface of the second four-way connector (11) is connected to the fourth interface of the first four-way connector (5) in sequence through the eleventh valve (16) and the seventh valve (15). The second interface of the second four-way connector (11) is connected to the first purification column (8) through the third valve (10). The third interface of the second four-way connector (11) is connected to the water removal device (21) through the second valve (20). The fourth interface of the second four-way connector (11) is connected to the first interface of the first three-way connector (30) through the twelfth valve (12). The second interface of the first three-way connector (30) is connected to the target carrier gas cylinder (24) through the fourth valve (23). The third interface of the first three-way connector (30) is connected to the pressure sensor (14) through the thirteenth valve (13).

4. The carrier gas replacement device for inert gas samples according to claim 3, characterized in that: The seventh valve (15) and the eighth valve (4) are both located at the interface position corresponding to the first four-way pipe joint (5).

5. The carrier gas replacement device for an inert gas sample according to claim 4, characterized in that: The eleventh valve (16) and the twelfth valve (12) are both located at the interface position corresponding to the second four-way pipe joint (11).

6. A method for replacing a carrier gas in an inert gas sample, using the carrier gas replacement device for an inert gas sample as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Close the first valve (22) and the fourth valve (23), and open the remaining valves, the circulation pump (9) and the vacuum pump (25) to evacuate the pipeline; Step 2: Start the two heating furnaces (7), heat to the preset working temperature, and maintain the preset working temperature for time T until the first preset pressure is reached in the pipeline. Then stop vacuuming and turn off the circulation pump (9). Step 3: Close the third valve (10), open the first valve (22), and fill the pipeline with sample gas from the gas sample source (28). Record the initial pressure P0 in the pipeline by reading the pressure sensor (14). Step 4: Open the third valve (10) and the sample gas enters the pipeline after the third valve (10) until the rate of decrease of the pressure sensor (14) reading is less than or equal to 10 Pa / min, then close the second valve (20) and the first valve (22). Step 5: Turn on the circulation pump (9) and the variable volume container (19). The variable volume container (19) is compressed or stretched, and in conjunction with the circulation pump (9), the sample gas flows back and forth between the first purification column (8) and the second purification column (29) to purify the sample gas until the reading of the pressure sensor (14) no longer changes. Then, turn off the circulation pump (9). At the same time, when the variable volume container (19) is stretched to its maximum volume, turn off the variable volume container (19) so that its volume no longer changes. Return to step 3 and open the second valve (20) until the sample gas pressure value in the gas sample source (28) drops to P1, where P0 > P1. Step 6: Adjust the outlet pressure of the target carrier gas cylinder (24) to P. x Open the fourth valve (23), and the target carrier gas blows the purified sample gas in the pipeline into the variable volume container (19). The pressure sensor (14) reads P. x Then, close the fourth valve (23) to complete the replacement of the carrier gas in the inert gas sample.

7. The carrier gas replacement method in an inert gas sample according to claim 6, characterized in that: Step 6 is followed by a pipe cleaning step: Step S1: Open the eighth valve (4), the ninth valve (2), the tenth valve (17) and the vacuum pump (25) to evacuate the pipeline until the pipeline reaches the second preset pressure, and then close the eighth valve (4) and the vacuum pump (25); wherein, the second preset pressure is less than 100 Pa; Step S2: Open the fourth valve (23) for T1 time and then close it. Return to step S1 and repeat N times. Then close all valves. T1 is 2s-3s and N is 3-5 times to complete the pipeline flushing.

8. The carrier gas replacement method in an inert gas sample according to claim 6, characterized in that: In step 2, the first preset pressure is less than 10 Pa; T ≥ 20 min.

9. The carrier gas replacement method in an inert gas sample according to claim 6, characterized in that: In step 1, opening the remaining valves also includes opening the ninth valve (2), the eighth valve (4), the fifth valve (6), the third valve (10), the twelfth valve (12), the thirteenth valve (13), the seventh valve (15), the eleventh valve (16), the tenth valve (17), the sixth valve (18), and the second valve (20). In step 3, closing the third valve (10) also includes closing the seventh valve (15), the eleventh valve (16), the eighth valve (4), and the ninth valve (2). In step 6, after closing the fourth valve (23), open the eleventh valve (16) and the seventh valve (15). When the change in the pressure sensor (14) reading is less than or equal to 50 Pa, close the sixth valve (18).

10. The carrier gas replacement method in an inert gas sample according to claim 6, characterized in that: In step 6, the target carrier gas in the target carrier gas cylinder (24) is high-purity argon, or high-purity helium, or high-purity nitrogen, with a purity greater than or equal to 99.999%.

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