A manual injection assist device for gas chromatograph gas quantification

Abstract

The utility model discloses a kind of for gas chromatograph gas quantitative manual sampling auxiliary device, including three-way valve, the first joint of three-way valve is connected with sampling tube, sampling tube is connected with sampling needle, the second joint of three-way valve is connected with gas inlet pipe, gas inlet pipe is connected with gas chromatograph, the third joint of three-way valve is connected with ferrule joint by connecting pipeline, ferrule joint side is connected with quantitative ring, the utility model is connected with sampling needle by sampling tube, the second joint of three-way valve is connected with gas inlet pipe, gas inlet pipe is connected with gas chromatograph, the third joint of three-way valve is connected with ferrule joint by connecting pipeline, ferrule joint side is connected with quantitative ring, the utility model is by using fixed volume quantitative ring as sampling unit, sampling volume only depends on the geometric volume of quantitative ring, unrelated with the manual extraction action of operator. Compared with the volume deviation caused by reading error, uneven pulling speed in the sampling mode of traditional syringe, fundamentally eliminate the influence of human factor, ensure that sampling volume is constant each time, greatly improve the accuracy and reliability of quantitative analysis.

Description

Technical Field

[0001] This utility model relates to the technical field, specifically to a manual sample injection auxiliary device for gas quantification in a gas chromatograph. Background Technology

[0002] Gas chromatographs are commonly used instruments for gas composition analysis. When analyzing gas samples, it is usually necessary to introduce the sample into the chromatograph. Due to limitations in gas sample collection, manual injection is often used, which involves drawing a certain volume of gas sample using a gas-tight syringe and quickly injecting it into the chromatograph's inlet.

[0003] However, this traditional manual sampling method has many drawbacks. First, it relies entirely on the operator's manual control and skill level; inconsistencies in extraction volume and injection speed directly affect the accuracy and reproducibility of quantitative analysis, introducing significant human error. Second, different operators, and even different operations by the same operator, can yield vastly different results. Finally, friction and gaps between the syringe barrel and needle shaft can lead to sample leakage or the introduction of outside air, causing sample contamination or analytical errors. For pressurized gas sources (such as gas bags or cylinders), direct syringe sampling makes it difficult to control sample pressure, potentially resulting in unrepresentative samples due to excessively high or low pressure.

[0004] There are currently no effective solutions to the problems in the relevant technologies. Utility Model Content

[0005] In view of the problems in related technologies, this utility model proposes a manual injection auxiliary device for gas quantification in gas chromatographs, so as to overcome the above-mentioned technical problems existing in the existing related technologies.

[0006] Therefore, the specific technical solution adopted by this utility model is as follows:

[0007] A manual injection auxiliary device for gas quantification in a gas chromatograph includes a three-way valve. The first connector of the three-way valve is connected to an injection tube, which is connected to an injection needle. The second connector of the three-way valve is connected to an inlet pipe, which is connected to the gas chromatograph. The third connector of the three-way valve is connected to a ferrule connector via a connecting pipe. A quantitative loop is connected to one side of the ferrule connector.

[0008] Furthermore, to facilitate the introduction of purge gas into the metering ring, one end of the metering ring is connected to a tee connector.

[0009] Furthermore, one end of the tee connector is connected to the vent pipe.

[0010] Furthermore, in order to precisely control and stabilize the pressure in the circuit, a vent valve and a pressure gauge are connected to the vent pipe.

[0011] Furthermore, one end of the tee is connected to the purge pipe, and the purge pipe is connected to the purge gas inlet connector.

[0012] Furthermore, to prevent gas backflow, a one-way valve is installed on the purge pipe.

[0013] Furthermore, the injection needle is connected to the sample gas bag.

[0014] The beneficial effects of this utility model are as follows:

[0015] (1) This device uses a fixed-volume quantitative loop as the sampling unit. The injection volume depends only on the geometric volume of the quantitative loop and is independent of the operator's manual extraction action. Compared with the volume deviation caused by reading errors and uneven extraction speed in traditional syringe sampling, it fundamentally eliminates the influence of human factors, ensuring a constant injection volume each time, greatly improving the accuracy and reliability of quantitative analysis. Furthermore, the "loading-injection" two-step operation is achieved through a three-way valve, making the process simple and the switching quick. The quantitative loop is connected to the system through a compression fitting, making it easy to disassemble and assemble, and allowing for quick replacement of quantitative loops of different volumes to meet different analytical needs. At the same time, this connection method has good sealing performance, small dead volume, supports long-term repeated use, and facilitates calibration and maintenance.

[0016] (2) This device is equipped with a pressure gauge and a pressure relief valve on the venting line, which can monitor the system pressure in real time during sampling and stabilize the loop pressure at a preset value through the pressure relief valve. This design ensures that the sample gas fills the metering loop under constant pressure, avoiding volume changes caused by fluctuations in sample source pressure or changes in ambient temperature. It is particularly suitable for accurate sampling of pressurized gas samples, significantly improving sample reproducibility. In addition, by setting a purge gas inlet connector and purge line, inert gas (such as high-purity nitrogen or helium) can be introduced before and after each sample injection to fully purge the metering loop, connecting line and injection channel, remove the residue of the previous sample, and effectively avoid "memory effect" and cross-contamination. At the same time, the one-way valve on the purge line can prevent gas from flowing back to the gas source or sample side, ensuring system safety and gas purity. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a front view of a manual sample injection auxiliary device for gas quantification in a gas chromatograph according to an embodiment of the present utility model;

[0019] Figure 2 This is a side view of a manual sample injection auxiliary device for gas quantification in a gas chromatograph according to an embodiment of the present invention.

[0020] Figure 3 This is a structural diagram of a manual sample injection auxiliary device for gas quantification in a gas chromatograph according to an embodiment of the present invention.

[0021] In the picture:

[0022] 1. Three-way valve; 2. Injection tube; 3. Injection needle; 4. Gas inlet tube; 5. Gas chromatograph; 6. Connecting pipe; 7. Compression fitting; 8. Quantitative loop; 9. Three-way fitting; 10. Vent tube; 11. Vent valve; 12. Pressure gauge; 13. Purge tube; 14. Purge gas connector; 15. One-way valve; 16. Sample gas bag. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] According to an embodiment of the present invention, a manual sample injection auxiliary device for gas quantification in a gas chromatograph is provided.

[0025] Example 1

[0026] like Figures 1-3 As shown, the manual sample injection auxiliary device for gas quantification in a gas chromatograph according to an embodiment of the present invention includes a three-way valve 1. The first connector of the three-way valve 1 is connected to the injection tube 2. The injection tube 2 is connected to the injection needle 3. The injection needle 3 is preferably a stainless steel piercing needle with sufficient mechanical strength and corrosion resistance. The injection needle 3 is connected to the sample gas bag 16. The injection needle 3 can be directly and vertically inserted into the sealing membrane of the gas sample bag (such as an aluminum foil composite gas bag, a Tedlar gas bag, etc.) to achieve safe and leak-free collection of gas samples in a closed container. The design of the injection needle 3 ensures the convenience and sealing of the sampling process, preventing the ingress of outside air or the escape of the sample. The second connector of the three-way valve 1 is connected to the inlet pipe 4, which is connected to the gas chromatograph 5. The inlet pipe 4 is made of high-temperature resistant, low-adsorption inert material. Its outlet end can be equipped with a guide sleeve or a special connector to facilitate the insertion of the silicone septum at the injection port of the gas chromatograph 5 and ensure that the gas is smoothly introduced into the vaporization chamber. The third connector of the three-way valve 1 is connected to the compression fitting 7 through the connecting pipe 6.

[0027] The ferrule connector 7 is used for detachable connection of the sample loop 8. The sample loop 8 is a tubular structure with a known precise volume, typically made of 316L stainless steel or perfluoroalkoxyethylene (PFA). Its inner diameter and length are precisely calculated and calibrated to achieve quantitative gas delivery of specific volumes (e.g., 0.5 mL, 1.0 mL, or 2.0 mL). Through the quick-connect design of the ferrule connector 7, users can replace sample loops 8 with different volumes to meet different analytical needs, achieving flexible adjustment of the injection volume. The replacement process can be completed without tools or with just a simple wrench, ensuring reliable sealing and a small dead volume.

[0028] like Figures 1-3 As shown, the other end of the metering loop 8 is connected to a tee connector 9 via a compression fitting 7. One end of the tee connector 9 is connected to a vent pipe 10. The outlet of the vent pipe 10 can be led to a fume hood or exhaust gas collection system to ensure a safe operating environment. A vent valve 11 and a pressure gauge 12 are connected to the vent pipe 10. The vent valve 11 is an adjustable precision valve that can be used to set the maximum working pressure of the system to prevent pipeline damage or leakage due to excessive gas pressure. The pressure gauge 12 is used to monitor the gas pressure in the circuit where the metering loop 8 is located in real time. The operator can determine whether the sample has stably filled the metering loop 8 by observing the reading of the pressure gauge 12. One end of the tee connector 9 is connected to a purge pipe 13, and the purge pipe 13 is connected to a purge gas inlet connector 14. This connector 14 is used to connect to an external inert gas source (such as high-purity nitrogen or helium). Before operating the device, after sample injection, or before changing samples, the purge gas source can be turned on to allow inert gas to flow sequentially through the purge tube 13, the metering loop 8, and the vent tube 10, thereby thoroughly cleaning the entire sample path, removing residual gas, and preventing cross-contamination. The purge tube 13 is equipped with a one-way valve 15, whose installation direction ensures that gas can only flow from the purge gas source to the metering loop 8 and cannot flow in the reverse direction. This design effectively prevents sample gas or gas from the chromatographic system from flowing back into the purge gas path during the switching of the three-way valve 1 or when the system pressure is abnormal.

[0029] To facilitate understanding of the above-mentioned technical solutions of this utility model, the working principle or operation method of this utility model in actual process will be described in detail below.

[0030] In summary, with the help of the above-mentioned technical solution of this utility model, in actual use, firstly, ensure that all connection points are correctly installed and well sealed. Switch the three-way valve 1 to the "Inject" position. At this time, the purger connector 14, the metering ring 8, and the air inlet pipe 4 form a continuous gas path. By introducing inert gas into the gas path, the metering ring 8 and the pipeline leading to the injection port can be cleaned and purged. Then, vertically insert the injection needle 3 into the gas bag 16 containing the sample gas, and switch the three-way valve 1 to the "Loading" position.

[0031] At this point, the injection needle 3, the quantitative loop 8, and the vent tube 10 form a continuous gas path, allowing the sample gas to smoothly enter and fill the quantitative loop 8. The sample gas enters the quantitative loop 8 from the gas bag 16 via the injection needle 3, while some gas is discharged from the system through the vent tube 10. Observe the pressure gauge 12; when the displayed pressure stabilizes at a set value, it indicates that the quantitative loop 8 has been completely filled with sample gas and has reached equilibrium. This process usually takes several minutes to ensure that the gas in the quantitative loop 8 is fully replaced, avoiding residual air or other impurities from affecting the analytical results. After sample collection, quickly but smoothly switch the three-way valve 1 to the "Inject" position. At this time, the channel originally connected to the injection needle 3 is closed, and the quantitative loop 8 is directly connected to the inlet tube 4 leading to the gas chromatograph 5. By opening the purge gas source, it propels the sample gas within the quantitative loop 8 forward, ultimately entering the gas chromatograph 5 for analysis. To prevent cross-contamination between different samples, the purge gas source remains open for a period after each injection, allowing inert gas to flow through the entire system, including the quantitative loop 8, the T-connector 9, and related tubing, thoroughly removing any residual sample gas. This step is crucial for ensuring the accuracy and reliability of subsequent sample analyses.

[0032] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A manual injection assist device for gas chromatograph gas quantification, characterized by, Includes a three-way valve (1), the first connector of the three-way valve (1) is connected to the injection tube (2), the injection tube (2) is connected to the injection needle (3), the second connector of the three-way valve (1) is connected to the air inlet tube (4), the air inlet tube (4) is connected to the gas chromatograph (5), the third connector of the three-way valve (1) is connected to the ferrule connector (7) through the connecting pipe (6), and a quantitative ring (8) is connected to one side of the ferrule connector (7).

2. A manual sample injection assist device for gas chromatograph gas quantification according to claim 1, wherein, One end of the metering ring (8) is connected to the tee connector (9).

3. A manual sample injection assist device for gas chromatograph gas quantification as defined in claim 2, wherein, One end of the tee connector (9) is connected to the vent pipe (10).

4. A manual sample injection assist device for gas chromatograph gas quantitation according to claim 3, wherein, A vent valve (11) and a pressure gauge (12) are connected to the vent pipe (10).

5. A manual sample injection assist device for gas chromatograph gas quantitation as defined in claim 2, wherein, One end of the tee connector (9) is connected to the purge pipe (13), and the purge pipe (13) is connected to the purge gas inlet connector (14).

6. A manual sample injection assist device for gas chromatograph gas quantitation as defined in claim 5, wherein, A one-way valve (15) is provided on the purge pipe (13).

7. A manual sample injection assist device for gas chromatograph gas quantitation as defined in claim 1, wherein, The injection needle (3) is connected to the sample gas bag (16).

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