Device with thermal desorption and direct and automatic gas sample injection functions

Abstract

The utility model relates to the field of gas detection, in particular to a device with thermal desorption and direct and automatic gas sample injection functions. Comprising a multi-position adsorption pipe sample placing disc, an adsorption pipe heating block, a sample transmission pipeline, a multi-position selection valve, a gas sample injection valve, a quantitative ring, a gas flow controller, a sampling pump, a two-position switching valve, a first electromagnetic valve, a second electromagnetic valve and a third electromagnetic valve. When the two-position switching valve is switched to a sample injection state (the first interface is communicated with the third interface), gas in the large injector is transmitted to the gas sample injection valve through the common end of the multi-position selector valve and the two-position switching valve, the sampling pump controls the extraction flow through the flow regulator (the adjustable throttle valve is linked with the sampling pump) on the pipeline, and the sampling pump is connected with the gas sample injection valve. And when the gas sample injection valve is switched to a sample injection state, the gas in the quantitative loop is brought into the chromatographic sample injection port by the carrier gas, so that quantitative sample injection is realized, and a sample injection amount error caused by manual operation is avoided.

Description

Technical Field

[0001] The utility model belongs to the field of gas detection, and particularly relates to a device with both thermal desorption and direct automatic gas sampling functions. Background Art

[0002] The detection of toxic gases in workplaces is an important link to ensure the health of workers. At present, there are mainly two detection methods: The first is to collect the gas into an adsorption tube with packing, then extract it with an organic solvent, and then quantitatively extract the extract and inject it into a gas chromatograph or mass spectrometer for analysis. This method requires a large amount of organic solvents, and long-term contact is likely to cause harm to the health of experimental personnel, and the solvent consumption increases the experimental cost and environmental burden; The second is to heat the adsorption tube by a thermal desorber, use an inert gas to purge the toxic gas into a 100 ml glass syringe, and then manually extract the gas for sampling and analysis. Although this method avoids the harm of organic solvents, the desorbers on the market generally need to manually process each adsorption tube one by one, and only one tube can be desorbed each time, so batch operation cannot be achieved. In addition, after the gas is desorbed into the syringe, manual extraction is required for sampling, and the injection volume is likely to be inaccurate due to human factors during the operation, affecting the repeatability and reliability of the detection results. Moreover, most detection devices can only process adsorption tube samples and cannot directly perform automatic quantitative sampling on gas samples collected by syringes / gas bags.

[0003] Therefore, there is an urgent need in the prior art for a device that can realize automatic desorption and quantitative sampling of multiple adsorption tubes, and also has the function of direct automatic sampling of gas samples, so as to improve the detection efficiency, reduce human errors, and at the same time reduce the risk of experimental personnel contacting harmful substances. Summary of the Utility Model

[0004] In order to overcome the problems of cumbersome operation, low efficiency, large human errors and single function in the prior art (only manual processing of single adsorption tube desorption and sampling can be realized, and automatic desorption of multiple tubes and direct quantitative sampling of gas samples cannot be achieved), a device with both thermal desorption and direct automatic gas sampling functions is proposed.

[0005] The technical solution of the utility model is as follows: A device with both thermal desorption and direct automatic gas sampling functions includes a multi-position adsorption tube placement sample tray, an adsorption tube heating block, a sample transmission pipeline, a multi-position selection valve, a gas sampling valve, a quantitative loop, a gas flow controller, a sampling pump, a two-position switching valve, and solenoid valves I, II, and III;

[0006] The multi-position adsorption tube placement sample tray is used to carry multiple adsorption tubes and automatically rotates through a driving device to transfer the adsorption tubes to the heating position of the adsorption tube heating block;

[0007] The adsorption tube heating block is arranged at the heating position and is used to heat the adsorption tube;

[0008] The upper end of the adsorption tube is connected to the first interface of the two-way switching valve through a sample transmission pipeline, and the lower end is connected to a gas flow controller, which is used to control the flow rate of inert gas into the adsorption tube;

[0009] The second interface of the two-way switching valve is connected to the common end of the multi-way selection valve, and the branch interfaces of the multi-way selection valve are connected to at least one large syringe for introducing the desorbed gas into the large syringe;

[0010] The third interface of the two-way switching valve is connected to the first interface of the gas sampling valve. The second interface of the gas sampling valve is successively connected to a quantitative loop and a sampling pump. The sampling pump is used to pump the gas in the large syringe to the quantitative loop, and the gas sampling valve can be switched to the sampling state so that the gas in the quantitative loop is carried into the chromatographic injection port by the carrier gas;

[0011] The backflush cleaning pipeline is respectively communicated with the nitrogen source, the gas sampling valve, and the exhaust interface of the multi-way selection valve, and solenoid valve 1, solenoid valve 2, and solenoid valve 3 are respectively arranged at the nitrogen inlet of the backflush cleaning pipeline, the bypass branch of the quantitative loop, and the exhaust branch.

[0012] Further, the two-way switching valve is a two-way three-way valve, which has two working modes: "desorption state" and "sampling state":

[0013] In the desorption state, the first interface and the second interface of the two-way switching valve are communicated, so that the adsorption tube is connected to the common end of the multi-way selection valve through the two-way switching valve, and then the desorbed gas is transmitted to the large syringe connected to the branch interface of the multi-way selection valve;

[0014] In the sampling state, the first interface and the third interface of the two-way switching valve are communicated, so that the gas in the large syringe is transmitted to the gas sampling valve through the common end of the multi-way selection valve and the two-way switching valve.

[0015] Further, solenoid valve 1 is arranged between the backflush gas inlet and the backflush interface of the gas sampling valve, solenoid valve 2 is arranged on the bypass pipeline between the sampling pump and the quantitative loop, and solenoid valve 3 is arranged at the exhaust interface of the multi-way selection valve. The three cooperate to control the backflush cleaning process.

[0016] Further, the multi-way selection valve is provided with an interface for a syringe / gas bag, and this interface is communicated with the common end of the multi-way selection valve through a pipeline. By switching the valve state of the multi-way selection valve, the gas sample in the syringe / gas bag can pass through the interface of the syringe / gas bag, the common end of the multi-way selection valve, the two-way switching valve, and the gas sampling valve and be transmitted to the quantitative loop, and automatic quantitative sampling is realized by the sampling pump.

[0017] Further, the gas flow controller is used to control the flow rate and volume of inert gas into the adsorption tube, and a flow regulator is arranged on the pipeline of the sampling pump to regulate the gas extraction flow rate during sampling.

[0018] Further, the flow regulator is an adjustable throttle valve, and the adjustable throttle valve is linked with the sampling pump to control the filling speed of the quantitative loop.

[0019] Further, the gas injection valve is a multi-position multi-way valve, including a "sampling state" and an "injection state". In the sampling state, it connects the large syringe and the quantitative loop, and in the injection state, it connects the quantitative loop and the chromatographic carrier gas path.

[0020] Further, the sample transfer pipeline is an inert material pipeline resistant to high pressure and corrosion, with a smooth inner wall.

[0021] Further, the interface of the syringe / gas bag is connected to the common end of the multi-position selection valve through a quick connector.

[0022] Advantages of the utility model:

[0023] 1. By setting up a multi-position adsorption tube placement sample tray and a driving device, multiple adsorption tubes can be carried and automatically rotated and transferred to the heating position of the adsorption tube heating block, realizing automatic batch thermal desorption of multiple adsorption tubes, without manual processing one by one, significantly improving the detection efficiency;

[0024] 2. After the heating block heats the adsorption tube, the inert gas is introduced into the adsorption tube by controlling the flow rate of the gas flow controller. The analyzed gas is introduced into the large syringe through a two-position switching valve (the first interface is connected to the second interface in the desorption state) via a multi-position selection valve. The whole process runs automatically, reducing manual intervention;

[0025] 3. When the two-position switching valve switches to the injection state (the first interface is connected to the third interface), the gas in the large syringe is transmitted to the gas injection valve through the common end of the multi-position selection valve and the two-position switching valve. The sampling pump controls the extraction flow rate through the flow regulator (adjustable throttle valve, linked with the sampling pump) on the pipeline, accurately pumping the gas into the quantitative loop. When the gas injection valve switches to the injection state, the gas in the quantitative loop is brought into the chromatographic injection port by the carrier gas, realizing quantitative injection and avoiding the injection volume error caused by manual operation;

[0026] 4. The multi-position selection valve is provided with a syringe / gas bag interface, which is connected to the common end through a quick connector. By switching the valve state of the multi-position selection valve, the gas sample in the syringe / gas bag can be sequentially transmitted to the quantitative loop through the interface, the common end, the two-position switching valve, and the gas injection valve, and automatic quantitative injection is realized by the sampling pump, which is compatible with the gas samples directly collected by the adsorption tube thermal desorption samples and the syringe / gas bag, and can expand the application range of the device;

[0027] 5. The pyrolysis desorption method is adopted to replace the organic solvent extraction, avoiding long-term contact of experimental personnel with harmful solvents, reducing solvent consumption, lowering experimental costs and environmental burdens. Additionally, the backflush cleaning pipeline connects the nitrogen source, the gas sampling valve and the evacuation interface of the multi-position selection valve. Solenoid valves one, two, and three respectively control the nitrogen inlet, the bypass branch of the quantitative loop, and the evacuation branch, jointly completing the backflush cleaning of the pipeline to ensure that the residual gas is effectively removed after each injection, improving the detection accuracy. Brief Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the desorption heating position of the adsorption tube of the present utility model;

[0029] Figure 2 It is a schematic diagram after the injection path of the two-position switching valve of the present utility model is switched;

[0030] Figure 3 It is a schematic diagram of the gas sampling valve of the present utility model in the injection state;

[0031] Figure 4 It is a schematic diagram of the backflush cleaning state of the present utility model.

[0032] The marks in the drawings are: 1. Adsorption tube; 2. Adsorption tube heating block; 3. Gas flow controller; 4. Two-position switching valve; 5. Multi-position selection valve; 6. Large syringe; 7. Gas sampling valve; 8. Quantitative loop; 9. Sampling pump; 10. Flow regulator; 11. Solenoid valve one; 12. Solenoid valve two; 13. Solenoid valve three. Detailed Embodiment

[0033] The present utility model will be further described below with reference to the drawings and embodiments.

[0034] Please refer to Figures 1-4 , the present utility model provides an embodiment: a device with both pyrolysis desorption and direct gas automatic injection, including a multi-position adsorption tube placement sample tray, an adsorption tube heating block 2, a sample transmission pipeline, a multi-position selection valve 5, a gas sampling valve 7, a quantitative loop 8, a gas flow controller 3, a sampling pump 9, a two-position switching valve 4, and solenoid valves one 11, two 12, and three 13;

[0035] The multi-position adsorption tube placement sample tray is used to carry multiple adsorption tubes 1 and automatically rotate through a driving device to transfer the adsorption tube 1 to the heating position of the adsorption tube heating block 2;

[0036] The driving device includes a stepping motor, a transmission gear set, and a rotating shaft provided below the multi-position adsorption tube placement sample tray. The motor drives the sample tray to automatically rotate around the rotating shaft through the gear set to transfer the adsorption tube to the heating position;

[0037] The adsorption tube heating block 2 is arranged at the heating position and is used to heat the adsorption tube 1; the upper end of the adsorption tube 1 is connected to the first interface of the two-position switching valve 4 through a sample transmission pipeline, and the lower end is connected to the gas flow controller 3. The gas flow controller 3 is used to control the flow rate of the inert gas introduced into the adsorption tube 1;

[0038] The second interface of the two-position switching valve 4 is connected to the common end of the multi-position selection valve 5, and the branch interfaces of the multi-position selection valve 5 are connected to at least one large syringe 6 for introducing the desorbed gas into the large syringe 6;

[0039] The third interface of the two-position switching valve 4 is connected to the first interface of the gas sampling valve 7. The second interface of the gas sampling valve 7 is sequentially connected to the quantitative loop 8 and the sampling pump 9. The sampling pump 9 is used to pump the gas in the large syringe 6 to the quantitative loop 8. The gas sampling valve 7 can be switched to the sampling state so that the gas in the quantitative loop 8 is carried into the chromatographic injection port by the carrier gas;

[0040] The backflush cleaning pipeline is respectively communicated with the nitrogen source, the gas sampling valve 7, and the exhaust interfaces of the multi-position selection valve 5, and the solenoid valve one 11, the solenoid valve two 12, and the solenoid valve three 13 are respectively arranged at the nitrogen inlet of the backflush cleaning pipeline, the bypass branch of the quantitative loop 8, and the exhaust branch for controlling the backflush cleaning of the pipeline by nitrogen.

[0041] In this embodiment: The driving device adopts a mechanical structure of a stepping motor, a transmission gear set and a rotating shaft to ensure the rotation accuracy of the sample disk, accurately position the adsorption tube 1 to the heating position, and realize the automatic transportation of the adsorption tube 1 in the pyrolysis desorption process. After the adsorption tube heating block 2 heats the adsorption tube 1, the gas flow controller 3 accurately controls the flow rate of the inert gas, making the desorption process run automatically, reducing manual intervention, ensuring the stability of the desorbed gas. The two-position switching valve 4 cooperates with the multi-position selection valve 5 to introduce the desorbed gas into the large syringe 6 in the desorption state, forming an automatic gas transmission path, providing an intermediate storage carrier for subsequent quantitative injection. When the two-position switching valve 4 is switched to the injection state, through the linkage of the gas sampling valve 7, the quantitative loop 8 and the sampling pump 9, the gas in the large syringe 6 is accurately pumped to the quantitative loop 8 to realize quantitative injection, avoiding the injection volume error caused by manual operation;

[0042] In addition, the backflush cleaning pipeline works in coordination with the solenoid valve one 11, the solenoid valve two 12, and the solenoid valve three 13 to use nitrogen to remove the residual gas in the pipeline, ensuring the detection accuracy and reducing the cross contamination.

[0043] Please refer to Figures 1-4, in this embodiment, the two-way switching valve 4 is a two-way three-way valve, which has two working modes: "analysis state" and "sampling state". In the analysis state, the first interface of the two-way switching valve 4 is connected to the second interface, so that the adsorption tube 1 is connected to the common end of the multi-way selection valve 5 through the two-way switching valve 4, and then the desorption gas is transmitted to the large syringe 6 connected to the branch interface of the multi-way selection valve 5. In the sampling state, the first interface of the two-way switching valve 4 is connected to the third interface, so that the gas in the large syringe 6 is transmitted to the gas sampling valve 7 through the common end of the multi-way selection valve 5 and the two-way switching valve 4. The two-way three-way design of the two-way switching valve 4 realizes the automatic switching between the analysis and sampling states, ensuring the orderly transmission of gas between the thermal desorption analysis path and the sampling path, and guaranteeing the coherence of the process.

[0044] Please refer to Figures 1-4 , in this embodiment, the solenoid valve 11 is arranged between the backflush gas inlet and the backflush interface of the gas sampling valve 7, the solenoid valve 12 is arranged on the bypass pipeline of the sampling pump 9 and the quantitative loop 8, and the solenoid valve 13 is arranged at the evacuation interface of the multi-way selection valve 5. The three work together to control the backflush cleaning process. The solenoid valve 11, the solenoid valve 12, and the solenoid valve 13 control the nitrogen inlet, the bypass branch, and the evacuation branch respectively, realizing the precise control of the backflush cleaning pipeline, ensuring the effective removal of residual gas, and improving the detection accuracy.

[0045] Please refer to Figures 1-4 , in this embodiment, the multi-way selection valve 5 is provided with an interface for a syringe / air bag, and this interface is connected to the common end of the multi-way selection valve 5 through a pipeline. By switching the valve state of the multi-way selection valve 5, the gas sample in the syringe / air bag can pass through the interface of the syringe / air bag, the common end of the multi-way selection valve 5, the two-way switching valve 4, and the gas sampling valve 7 and be transmitted to the quantitative loop 8, and the sampling pump 9 realizes automatic quantitative sampling. The syringe / air bag interface of the multi-way selection valve 5 is connected to the common end through a quick connector, supporting the import of syringe / air bag samples by switching the valve state, being compatible with thermal desorption samples and directly collected gas samples, and expanding the application range of the device.

[0046] Please refer to Figures 1-4 , in this embodiment, the gas flow controller 3 is used to control the flow rate and volume of the inert gas introduced into the adsorption tube 1. A flow regulator 10 is arranged on the pipeline of the sampling pump 9 to regulate the gas extraction flow rate during sampling. The gas flow controller 3 precisely controls the flow rate of the inert gas, and the flow regulator 10 is linked with the sampling pump 9 to regulate the extraction flow rate, ensuring the stable output of the desorption gas and the precise filling of the quantitative loop 8.

[0047] Please refer to Figures 1-4, in this embodiment, the flow regulator 10 is an adjustable throttle valve. The adjustable throttle valve is linked with the sampling pump 9 to control the sample filling speed of the quantitative loop 8. As the flow regulator 10, the adjustable throttle valve is linked with the sampling pump 9 to control the sample filling speed, avoiding the injection volume deviation caused by unstable flow rate and ensuring the quantitative injection accuracy.

[0048] Please refer to Figures 1-4 , in this embodiment, the gas injection valve 7 is a multi-position multi-way valve, including a "sampling state" and an "injection state". In the sampling state, it connects the large syringe 6 and the quantitative loop 8. In the injection state, it connects the quantitative loop 8 and the chromatographic carrier gas path. The multi-position multi-way design of the gas injection valve 7 realizes the switching between the sampling and injection states, ensuring that the gas in the quantitative loop 8 is accurately carried into the chromatographic injection port by the carrier gas, and the automated quantitative injection work can be completed.

[0049] Please refer to Figures 1-4 , in this embodiment, the sample transfer pipeline is a high-pressure-resistant and corrosion-resistant inert material pipeline with a smooth inner wall. The setting of using high-pressure-resistant and corrosion-resistant inert materials and a smooth inner wall for the sample transfer pipeline can avoid chemical reactions or residues between the sample and the pipeline, ensuring the purity and accuracy of the gas transmission process.

[0050] Please refer to Figures 1-4 , in this embodiment, the interface of the syringe / air bag is connected to the common end of the multi-position selection valve 5 through a quick connector. Connecting the syringe / air bag interface to the common end of the multi-position selection valve 5 through a quick connector facilitates the quick installation and disassembly of the sample container.

[0051] Working principle: During use, first place multiple adsorption tubes 1 on the multi-position adsorption tube placement sample tray. The stepping motor in the driving device drives the sample tray to automatically rotate around the rotation axis through the transmission gear set, and sequentially transfers the adsorption tubes 1 to the heating position of the adsorption tube heating block 2. The adsorption tube heating block 2 heats the adsorption tubes 1;

[0052] During the heating process, the gas flow controller 3 controls the inert gas to enter from the lower end of the adsorption tube 1, and the flow rate and volume are accurately adjusted by the gas flow controller 3. The analyzed gas enters the two-way switching valve 4 from the upper end of the adsorption tube 1 through the sample transfer pipeline;

[0053] As shown in the appendix Figure 1 , when the two-way switching valve 4 is in the "analysis state" (the first interface is connected to the second interface), the analyzed gas enters the common end of the multi-position selection valve 5 through the two-way switching valve 4, and then is introduced into the large syringe 6 for storage through the branch interface of the multi-position selection valve 5;

[0054] As shown in the appendix Figure 2, when sample injection is required, the two-way switching valve 4 is switched to the "sample injection state" (the first interface is connected to the third interface), and the gas in the large syringe 6 is transmitted to the first interface of the gas sampling valve 7 through the common end of the multi-way selection valve 5 and the two-way switching valve 4. At this time, the gas sampling valve 7 is in the "sampling state", connecting the large syringe 6 and the quantitative loop 8. The sampling pump 9 is started, and the flow regulator 10 (adjustable throttle valve) on the pipeline is linked with the sampling pump 9 to control the gas extraction flow rate, and the gas in the large syringe 6 is accurately pumped into the quantitative loop 8;

[0055] As attached Figure 3 , after the quantitative loop 8 is filled with the sample, the gas sampling valve 7 is switched to the "sample injection state", connecting the quantitative loop 8 and the chromatographic carrier gas path. The gas in the quantitative loop 8 is carried into the chromatographic injection port by the carrier gas, realizing quantitative sample injection. At this time, the substance to be analyzed is carried into the chromatograph by the chromatographic carrier gas for analysis;

[0056] For the gas sample in the syringe / air bag, its interface is connected to the common end of the multi-way selection valve 5 through a quick connector, and the valve state of the multi-way selection valve 5 is switched. The gas sample is sequentially transmitted to the quantitative loop 8 through the syringe / air bag interface, the common end of the multi-way selection valve 5, the two-way switching valve 4, and the gas sampling valve 7, and automatic quantitative sample injection is also realized by the sampling pump 9;

[0057] As attached Figure 4 , after the sample injection is completed, the backflush cleaning of the pipeline is started: the solenoid valve 11 opens the nitrogen inlet, and the nitrogen from the nitrogen source is introduced into the pipeline through the backflush cleaning pipeline. The solenoid valve 12 controls the bypass branch of the quantitative loop 8, and the solenoid valve 13 controls the evacuation interface of the multi-way selection valve 5. The three work together, and nitrogen backflushes the gas sampling valve 7, the multi-way selection valve 5 and the relevant pipelines to remove the residual gas and ensure the detection accuracy;

[0058] During the whole process, the sample transmission pipeline uses an inert material pipeline with high pressure resistance and corrosion resistance and a smooth inner wall to ensure the purity of gas transmission. The driving device ensures the accurate positioning of the adsorption tube 1. The gas flow controller 3 and the flow regulator 10 cooperate to control the flow rate. Each valve realizes the automatic switching of the desorption, sample injection, and cleaning processes through state switching, which is compatible with the thermal desorption samples of the adsorption tube and the samples directly collected by the syringe / air bag, improving the detection efficiency and applicability.

Claims

1. A device with both thermal desorption and direct gas auto-sampling, characterized in that: It includes a multi-position adsorption tube placement sample tray, an adsorption tube heating block (2), a sample transmission pipeline, a multi-position selection valve (5), a gas injection valve (7), a quantitative loop (8), a gas flow controller (3), a sampling pump (9), a two-position switching valve (4), solenoid valve one (11), solenoid valve two (12), and solenoid valve three (13). The multi-position adsorption tube placement sample tray is used to carry multiple adsorption tubes (1) and automatically rotate through a driving device to transfer the adsorption tubes (1) to the heating position of the adsorption tube heating block (2). The adsorption tube heating block (2) is arranged at the heating position and is used to heat the adsorption tubes (1). The upper end of the adsorption tube (1) is connected to the first interface of the two-position switching valve (4) through the sample transmission pipeline, and the lower end is connected to the gas flow controller (3). The gas flow controller (3) is used to control the flow rate of inert gas introduced into the adsorption tube (1). The second interface of the two-position switching valve (4) is connected to the common end of the multi-position selection valve (5), and the branch interface of the multi-position selection valve (5) is connected to at least one large syringe (6) for introducing the desorbed gas into the large syringe (6). The third interface of the two-position switching valve (4) is connected to the first interface of the gas injection valve (7). The second interface of the gas injection valve (7) is sequentially connected to the quantitative loop (8) and the sampling pump (9). The sampling pump (9) is used to pump the gas in the large syringe (6) to the quantitative loop (8). The gas injection valve (7) can be switched to the injection state to make the gas in the quantitative loop (8) be carried into the chromatographic injection port by the carrier gas. The backflush cleaning pipeline is respectively communicated with the nitrogen source, the gas injection valve (7), and the exhaust interface of the multi-position selection valve (5). And solenoid valve one (11), solenoid valve two (12), and solenoid valve three (13) are respectively arranged at the nitrogen inlet of the backflush cleaning pipeline, the bypass branch of the quantitative loop (8), and the exhaust branch.

2. The device with both thermal desorption and direct gas auto-sampling according to claim 1, wherein: The two-position switching valve (4) is a two-position three-way valve and has two working modes: "desorption state" and "injection state". In the desorption state, the first interface and the second interface of the two-position switching valve (4) are communicated, so that the adsorption tube (1) is connected to the common end of the multi-position selection valve (5) through the two-position switching valve (4), and then the desorbed gas is transmitted to the large syringe (6) connected to the branch interface of the multi-position selection valve (5). In the injection state, the first interface and the third interface of the two-position switching valve (4) are communicated, so that the gas in the large syringe (6) is transmitted to the gas injection valve (7) through the common end of the multi-position selection valve (5) and the two-position switching valve (4).

3. The device with both thermal desorption and direct gas auto-sampling according to claim 1, characterized in that: Solenoid valve one (11) is arranged between the backflush gas inlet and the backflush interface of the gas injection valve (7). Solenoid valve two (12) is arranged on the bypass pipeline between the sampling pump (9) and the quantitative loop (8). Solenoid valve three (13) is arranged at the exhaust interface of the multi-position selection valve (5). The three cooperate to control the backflush cleaning process.

4. A device with both thermal desorption and direct gas auto-sampling, as claimed in claim 1, characterized in that: The multi-position selection valve (5) is provided with an interface for a syringe / air bag, and this interface is connected to the common end of the multi-position selection valve (5) through a pipeline. By switching the valve state of the multi-position selection valve (5), the gas sample in the syringe / air bag can pass through the interface of the syringe / air bag, the common end of the multi-position selection valve (5), the two-position switching valve (4), and the gas sampling valve (7) and be transmitted to the quantitative loop (8), and automatic quantitative sampling is achieved by the sampling pump (9).

5. The device with both thermal desorption and direct gas auto-sampling according to claim 1, characterized in that: The gas flow controller (3) is used to control the flow rate and volume of the inert gas introduced into the adsorption tube (1). A flow regulator (10) is provided on the pipeline of the sampling pump (9) to adjust the gas extraction flow rate during sampling.

6. The device with both thermal desorption and direct gas automatic sampling according to claim 5, characterized in that: The flow regulator (10) is an adjustable throttle valve, and the adjustable throttle valve is linked with the sampling pump (9) to control the filling speed of the quantitative loop (8).

7. The device with both thermal desorption and direct gas auto-sampling according to claim 1, characterized in that: The gas sampling valve (7) is a multi-position multi-way valve, including a "sampling state" and an "injection state". In the sampling state, it connects the large syringe (6) and the quantitative loop (8), and in the injection state, it connects the quantitative loop (8) and the chromatographic carrier gas path.

8. The device with both thermal desorption and direct gas auto-sampling according to claim 1, characterized in that: The sample transmission pipeline is a high-pressure-resistant and corrosion-resistant inert material pipeline with a smooth inner wall.

9. An apparatus with both thermal desorption and direct gas automatic sampling according to claim 4, characterized in that: The interface of the syringe / air bag and the common end of the multi-position selection valve (5) are connected through a quick connector.

Images