Movable portable gas distribution device

Abstract

The utility model belongs to the technical field of gas analysis, and particularly relates to a movable portable gas distribution device. The gas distribution device comprises a cylinder body, a piston, a porous cylinder head, a three-way valve and a pipe joint, wherein the outer wall of the cylinder body is wrapped with a heating layer. Liquid, gas or diluent gas is injected into the cylinder through the three-way valve, a liquid or gas sample is configured to have the concentration required by detection through vaporization of the heating layer and control of the piston, and then the liquid or gas sample is guided into the adsorption pipe or the sample injection pipeline through the pipe joint to be analyzed and detected. The integrated structural design is utilized, liquid gasification, concentration dilution and sample injection / adsorption sample injection are integrated into a whole, and the device is high in integration level, small in size, convenient to use, high in stability and accuracy and capable of being widely applied to industrial production. And the requirements of national defense application such as detection of various unconventional compounds and instrument calibration in a closed environment can be met.

Description

Technical Field

[0001] The utility model belongs to the technical field of gas analysis, and particularly relates to a movable and portable gas mixing device. Background Art

[0002] As an important branch of chromatographic science, gas chromatography (GC) and gas chromatography-mass spectrometry (GCMS) have become an important part of analytical chemistry. The gas chromatography technology can effectively separate various compounds in a mixture, and the mass spectrometry part can complete the qualitative and quantitative detection of compounds. Because of its ultra-high separation ability, wide detection range, excellent resolution of the composition and structure of substances, and stable reproducibility, it has become an indispensable research method in the fields of materials science, environmental science, pharmaceutical science, food science, aerospace science, etc.

[0003] In the field of ambient air detection, GC and GCMS have also become the main analytical methods for organic matter detection. Standard gases are used for quantitative analysis during the detection process. Standard gas is a kind of mixed gas, which is synthesized by high-purity substances with different component contents in a certain proportion. It is prepared by using one or several high-purity component raw gases as dilution gases and adding another high-purity component raw gas as background gas. The common methods for preparing standard mixed gases in industry mainly include weighing method, comparison method, permeation method, partial pressure method, saturation method, dilution method, flow method, etc. However, in a complex environment such as a confined space in a ship's cabin, the components of the compounds in the ambient air are particularly complex, and many of the compounds to be detected are unconventional compounds. It is difficult to supply the standard gas or lack the corresponding standard gas for quantitative analysis. And when calibrating the instrument on-site, due to considerations such as limited space and safety in the confined environment, using a standard gas cylinder will also cause inconvenience. Therefore, carrying a small amount of standard liquid for on-site portable gas mixing meets the application requirements in a narrow space scenario.

[0004] In the relevant standards for environmental detection, the method for preparing the calibration curve usually first configures the standard solution into a standard series of concentrations, then puts the standard series of solutions into an injection device, connects an adsorption tube, and then purges with an inert gas for 10 minutes and then removes and seals it. This method involves multiple steps such as concentration dilution, vaporization, sampling, and injection / adsorption injection of the corresponding compound liquid. This method has the disadvantages of cumbersome steps, easy mistakes in manual operation, and many external environmental interferences. The obtained detection results often have problems such as large deviations in parallel results, directly affecting the stability and accuracy of the detection results. Summary of the Utility Model

[0005] In view of the deficiencies in the prior art, the present utility model provides a movable and portable gas distribution device. By means of an integrated structural design, multiple steps such as transferring standard liquid in the preparation of standard gas, vaporizing the liquid, diluting the concentration for gas distribution, sampling / enriching, etc. are integrated into one, and the structure is small and convenient to carry. It is applicable to the gas distribution of gas standard samples, the vaporization sampling / adsorption sampling detection of liquid standard samples, and the calibration of instruments, meeting the application requirements in narrow space scenarios such as confined spaces.

[0006] Specifically, the present utility model provides the following technical solutions:

[0007] A movable and portable gas distribution device, comprising:

[0008] A cylinder body, the outer wall of which is wrapped with a heating layer;

[0009] A piston, which is arranged at one end of the cylinder body and is configured to move forward and backward relative to the cylinder body in a manner that its outer peripheral surface is in sliding contact with the inner peripheral surface of the cylinder body;

[0010] A porous cylinder head, which is arranged at the other end of the cylinder body, and is provided with a liquid sampling hole, a gas sampling hole, and a gas sampling outlet hole located on the same circumference;

[0011] A three-way valve, which is arranged at the front end (i.e., the end far from the cylinder body) of the porous cylinder head, and is provided with a flow-through hole; and the three-way valve can rotate relative to the porous cylinder head. Driven by the rotation of the three-way valve, it can be switched between the connection of the liquid sampling hole and the flow-through hole, the connection of the gas sampling hole and the flow-through hole, or the connection of the gas sampling outlet hole and the flow-through hole;

[0012] A pipe joint, which is arranged at the front end of the three-way valve and is connected and docked with the flow-through hole of the three-way valve.

[0013] The utility model forms a gas distribution chamber inside the cylinder body through the cylinder body, pistons at both ends of the cylinder, and a porous cylinder head. During use, first connect the pipe joint to the dilution gas pipeline, rotate the three-way valve so that the gas sampling hole communicates with the flow hole (the gas outlet hole is kept sealed with the liquid sampling hole), move the piston to fill a certain amount of dilution gas, then disconnect the pipe joint, adjust the temperature of the heating layer according to the vaporization temperature, wait for the temperature to stabilize, rotate the three-way valve so that the liquid sampling hole communicates with the flow hole, inject the compound liquid standard sample into the vaporization chamber, keep it for a period of time until it is completely vaporized, then fill the dilution gas again for volume determination, record the volume of the dilution gas through the volume scale, connect the pipe joint to the adsorption tube or the instrument sampling port pipeline, rotate the three-way valve so that the gas outlet hole communicates with the flow hole, and move the piston to discharge the gas in the gas distribution chamber to the adsorption tube or the instrument sampling port pipeline, thus integrating liquid vaporization, concentration dilution, and sample injection / adsorption injection, with high integration, small volume, and portability. And it can improve the stability and accuracy of the detection results.

[0014] Preferably, the inner wall of the cylinder body is inertized, thereby reducing the adsorption of gas by the inner wall.

[0015] Preferably, volume scale marks are provided on the outer wall of the cylinder body. The outer wall of the cylinder body at the corresponding positions of the volume scale marks is not wrapped with a heating layer, forming a concave part on the cylinder body. The piston is fixedly connected with a measuring rod that cooperates with the concave part on the cylinder body. While changing the internal volume of the gas distribution chamber by pushing and pulling the piston, the volume in the gas distribution chamber can be accurately read through the measuring rod, which is beneficial to accurately calculating the concentration of the prepared gas.

[0016] Preferably, a temperature control device is provided inside the heating layer, which can control the temperature of the liquid in the gas distribution chamber for vaporization;

[0017] The outside of the heating layer is wrapped with a heat-insulating shell.

[0018] The utility model can conveniently change the gas distribution working condition by rotating the three-way valve to switch the inlet and outlet channels. Preferably, a sealing gasket (such as the elastic rubber gasket commonly used at the gas chromatography sampling port, which the needle can penetrate and can seal after the needle is pulled out due to its elasticity) is installed in the liquid sampling port on the porous cylinder head, and one-way valves are installed in both the gas sampling hole and the gas outlet hole, ensuring the airtightness of the vaporization chamber.

[0019] Preferably, both the three-way valve and the porous cylinder head are disc-shaped, and the three-way valve and the porous cylinder head are sealed by an O-ring.

[0020] Preferably, the outer surface of the pipe joint is provided with an external thread structure, which can be connected to the gas pipeline for the introduction of standard gas / dilution gas and the direct sampling of samples; a sealing ring is provided inside the pipe joint, which can be connected to the adsorption tube for adsorption tube sampling.

[0021] The beneficial effects of the present utility model are at least as follows:

[0022] 1) The portable and movable gas distribution device provided by the present utility model integrates the functions of standard liquid transfer, liquid gasification, concentration dilution, and sampling / enrichment in the configuration of standard gas through an integrated structural design, and has a small and portable structure;

[0023] 2) The portable and movable gas distribution device provided by the present utility model is used in combination with the volume scale marks on the outer wall of the cylinder body of the gas distribution chamber. The piston first reads the gas volume after the standard liquid is gasified through the connecting rod, and then introduces the carrier gas to a certain volume, so that the concentration of the configured gas can be accurately calculated;

[0024] 3) The portable and movable gas distribution device provided by the present utility model is equipped with a three-way valve at the front end of the porous cylinder head to switch the inlet and outlet channels, a sealing gasket is installed at the liquid sampling hole, and one-way valves are installed in the gas sampling hole and the gas outlet hole, which ensures the tightness inside the gasification cylinder body and reduces the interference of the external environment;

[0025] 4) The portable and movable gas distribution device provided by the present utility model uses an outer-cladding type heating for the heating layer, so that the heat is evenly distributed during the gasification process. And an insulating outer shell is added to the outer layer, which can be operated in a hand-held manner;

[0026] 5) The portable and movable gas distribution device provided by the present utility model has a threaded structure on the outer side of the pipe joint and a sealing ring is installed inside to connect the adsorption tube, that is, it can be connected to the gas pipeline, and at the same time meets the connection with various types of collection adsorption tubes, and can ensure the sealing effect during the gas transmission process. Description of the Drawings

[0027] Figure 1 is a schematic structural diagram of a portable and movable gas distribution device of the present utility model.

[0028] Figure 2 is a schematic structural diagram of a portable and movable gas distribution device of the present utility model.

[0029] Figure 1-2 In [the figure], 1, cylinder body; 2, volume scale mark; 3, piston; 4, porous cylinder head; 5, measuring rod; 6, three-way valve; 7, heating layer; 8, pipe joint.

[0030] Figure 3 is the total ion current chromatogram of 14 alkane compounds obtained by detection after the use of a portable and movable liquid gasification / dilution gas distribution device of the present utility model.

[0031] Figure 3Among them, 1. n-pentane; 2. n-hexane; 3. n-heptane; 4. methylcyclohexane; 5. n-octane; 6. n-nonane; 7. n-decane; 8. undecane; 9. dodecane; 10. tridecane; 11. tetradecane; 12. pentadecane; 13. hexadecane; 14. heptadecane.

[0032] Figure 4 This is the total ion current chromatogram of 13 benzene series compounds obtained by detecting after using a movable and portable liquid gasification / dilution gas mixing device of the present utility model.

[0033] Figure 4 Among them, 1. benzene; 2. toluene; 3. chlorobenzene; 4. ethylbenzene; 5. p-xylene; 6. m-xylene; 7. o-xylene; 8. isopropylbenzene; 9. trimethylbenzene; 10. styrene; 11. dichlorobenzene; 12. trichlorobenzene; 13. naphthalene.

[0034] Figure 5 This is the total ion current chromatogram of 6 monoterpenoid compounds obtained by detecting after using a movable and portable liquid gasification / dilution gas mixing device of the present utility model.

[0035] Figure 5 Among them, 1. α-pinene; 2. myrcene; 3. 3-carene; 4. D-limonene; 5. D-camphor; 6. longifolene. Detailed implementation manners

[0036] The present utility model provides a movable and portable gas mixing device, mainly aiming at the situation that when using GC or GC / MS for quantitative analysis of some unconventional gas compounds and there is no corresponding standard gas for quantification, a movable and portable device that integrates liquid gasification, concentration dilution, injection / adsorption injection is proposed. This device has a high integration degree, and at the same time, it is small in volume, portable to use, and has high stability and accuracy.

[0037] To make the purpose, technical solutions and advantages of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be described clearly and completely below. The following embodiments are used to illustrate the present utility model, but are not used to limit the scope of the present utility model. For those not specifying specific techniques or conditions in the embodiments, they shall be carried out according to the techniques or conditions described in the literature in this field, or according to the product instructions.

[0038] Embodiment 1

[0039] Embodiment 1 provides a movable and portable liquid gasification / dilution gas mixing device, which can be partially referred to Figure 1-2 and includes:

[0040] A cylinder 1, the inner wall of the cylinder 1 is inertized, and the outer wall of the cylinder 1 is wrapped with a heating layer 7; a temperature control device is arranged inside the heating layer, and an insulating outer shell is wrapped outside.

[0041] A piston 3 is arranged at one end of the cylinder body 1 and configured to move forward and backward relative to the cylinder body in a manner that its outer peripheral surface is in sliding contact with the inner peripheral surface of the cylinder body; a volume scale mark 2 is provided on the outer wall of the cylinder body 1, and the outer wall of the cylinder body 1 at the corresponding position of the volume scale mark 2 is not wrapped with a heating layer 7, forming a recess on the cylinder body 1. The piston 3 is fixedly connected with a measuring rod 5 that cooperates with the recess on the cylinder body 1;

[0042] A porous cylinder head 4 is arranged at the other end of the cylinder body 1. The cylinder body, the pistons at both ends of the cylinder body, and the porous cylinder head form a gas distribution chamber inside the cylinder body; the porous cylinder head 4 is provided with a liquid sampling hole, a gas sampling hole, and a gas sampling outlet hole on the same circumference, and the liquid sampling hole, the gas sampling hole, and the gas sampling outlet hole are respectively communicated with the gas distribution chamber; a sealing gasket is installed in the liquid sampling port on the porous cylinder head 4, and one-way valves are installed in both the gas sampling hole and the gas sampling outlet hole;

[0043] A three-way valve 6 is arranged at the front end of the porous cylinder head 4, and a flow-through hole is provided thereon; and the three-way valve 6 can rotate relative to the porous cylinder head 4. Driven by the rotation of the three-way valve 6, it can be switched between the liquid sampling hole being communicated with the flow-through hole, or the gas sampling hole being communicated with the flow-through hole, or the gas sampling outlet hole being communicated with the flow-through hole;

[0044] Both the three-way valve 6 and the porous cylinder head 4 are disc-shaped, and are sealed between the three-way valve 6 and the porous cylinder head 4 by an O-ring;

[0045] A pipe joint 8 is arranged at the front end of the three-way valve 6 and is communicated and docked with the flow-through hole of the three-way valve 6; the outer surface of the pipe joint 8 is provided with an external thread structure, and a sealing ring is arranged inside.

[0046] Example 2

[0047] Using a movable and portable gas distribution device provided in Example 1 to perform gasification / dilution treatment on an alkane liquid standard substance. The standard gas after the device treatment enters a Tenax adsorption tube and is detected by a thermal desorption-gas chromatography-mass spectrometry instrument to obtain a total ion chromatogram of 14 alkane compounds. See Figure 3Using this device to prepare standard curves in two ways. First, accurately pipette 0.0 μL, 5.0 μL, 10.0 μL, 20.0 μL, 50.0 μL, and 100.0 μL of a standard solution with a concentration of 1000 mg / L respectively, and make up to 1.0 mL with methanol to prepare standard series with mass concentrations of 0.0 mg / L, 5.0 mg / L, 10.0 mg / L, 20.0 mg / L, 50.0 mg / L, and 100.0 mg / L respectively. Accurately pipette 10 μL of each standard series solution into this device, connect the well-aged sampling tube, and prepare a standard series of adsorption tubes for the analysis of 14 alkane compounds with contents of 0 ng, 50 ng, 100 ng, 200 ng, 500 ng, and 1000 ng by thermal desorption gas chromatography; the other way is to pipette 10.0 μL of a standard solution with a concentration of 1000 mg / L into this device, rotate the three-way valve to use the dilution gas for gas distribution, and prepare a standard series of adsorption tubes for the analysis of 14 alkane compounds with contents of 0 ng, 50 ng, 100 ng, 200 ng, 500 ng, and 1000 ng by changing the gas volume in the gas distribution chamber. Taking the peak area as the ordinate and the mass of the analyte as the abscissa, draw the standard curve.

[0048] At the same time, use this device to test the precision and accuracy of 14 alkane compound samples. Accurately pipette 8.0 μL and 60.0 μL of a standard solution with a concentration of 1000 mg / L respectively, and make up to 1.0 mL with methanol to prepare intermediate reserve solutions with mass concentrations of 8.0 mg / L and 60.0 mg / L respectively. Pipette 10 μL of the intermediate reserve solution into this device, connect the well-aged sampling tube, and prepare standard samples of 14 alkane compounds with contents of 80 ng and 600 ng respectively. Repeat the above steps for 6 determinations to obtain their accuracy and precision. The details of the test results are shown in Table 1.

[0049] The test results show that the standard series of 14 alkane compounds prepared by this device has good linearity, and the correlation coefficients (r) are all greater than 0.995. The ranges of accuracy (relative deviation) and precision (relative standard deviation) are 0.5% - 8.1% and 1.4% - 5.6% respectively, meeting all the indicators in instrument detection and calibration.

[0050] Table 1 Correlation coefficients, accuracy, and precision of the standard curves of 14 alkane compounds

[0051]

[0052]

[0053] Example 3

[0054] The standard gas of benzene series compounds was diluted by using a movable portable gas distribution device provided in Example 1. The diluted standard gas of the device was injected into a gas chromatography - mass spectrometry (GC - MS) instrument by valve injection for detection, and the total ion current chromatogram of 13 benzene series compounds was obtained. See Figure 4 . Using the gas distribution function of this device for dilution and gas distribution of the standard gas, the standard gas of benzene series compounds with a concentration of 100.0 μmol / mol was diluted and injected into the gas distribution chamber. By introducing the dilution gas and changing the gas volume in the gas distribution chamber, standard series with concentrations of 0.0 μmol / mol, 5.0 μmol / mol, 10.0 μmol / mol, 30.0 μmol / mol, 60.0 μmol / mol, and 100.0 μmol / mol were prepared. With the peak area as the ordinate and the mass of the analyte as the abscissa, a standard curve was plotted. At the same time, the precision and accuracy of 13 benzene series compound samples were tested using this device. In the same way as the above steps, standard gases with concentrations of 15 μmol / mol and 50 μmol / mol were prepared and injected into the gas chromatography - mass spectrometry instrument by valve injection for detection. The above steps were repeated 6 times to obtain their accuracy and precision. The details of the test results are shown in Table 2.

[0055] The test results show that the 13 - benzene - series - compound standard series prepared by this device has good linearity, and the correlation coefficients (r) are all greater than 0.995. The ranges of accuracy (relative deviation) and precision (relative standard deviation) are 0.8% - 4.3% and 0.6% - 4.6% respectively, meeting all the indicators in instrument detection and calibration.

[0056] Table 2 Correlation coefficients, accuracy, and precision of the standard curves of 13 benzene series compounds

[0057]

[0058] Example 4

[0059] The reagent of monoterpenoid compounds in the unconventional gas component phytoncide was mixed into a liquid standard substance and subjected to gasification / dilution treatment by using a movable portable gas distribution device provided in Example 1. The standard gas after the device treatment was injected into a gas chromatography - mass spectrometry instrument by valve injection for detection, and the total ion current chromatogram of 6 monoterpenoid compounds was obtained. See Figure 5 . By accurately pipetting 10.0 μL of chromatographically pure reagent into this device for vaporization, and then using the gas distribution function of this device for dilution gas distribution, by changing the gas volume in the gas distribution chamber, concentrations of approximately 0.0 mg / m 3 , 0.5 mg / m 3 , 1.0 mg / m 3 , 2.0 mg / m 3 , 5.0 mg / m 3, 10.0 mg / m 3 standard series. Taking the peak area as the ordinate and the mass of the analyte as the abscissa, a standard curve is plotted. At the same time, the precision and accuracy of 6 monoterpene compound samples are tested using this device. In the same way as the above steps, standard gases with mass concentrations of 1.5 mg / m 3 and 6.0 mg / m 3 are configured and injected into the gas chromatography-mass spectrometry for detection by valve injection. The above steps are repeated 6 times to obtain their accuracy and precision. The details of the test results are shown in Table 3.

[0060] The test results show that the standard series of 6 monoterpene compounds prepared by this device has good linearity, and the correlation coefficients (r) are all greater than 0.995. The ranges of accuracy (relative deviation) and precision (relative standard deviation) are 1.9% - 7.7% and 0.9% - 6.3% respectively, meeting all the indicators in instrument detection and calibration.

[0061] Table 3 Correlation coefficients, accuracy and precision of the standard curves of 6 monoterpene compounds

[0062]

[0063] As can be seen from the above embodiments, the portable gas mixing device provided by the present utility model has the advantages of small volume, portability, simple operation, low detection limit, high accuracy, etc., and can meet the application requirements of special scenarios for detecting various unconventional compounds in a closed environment.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model, not to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present utility model.

Claims

1. A portable gas distribution device, characterized in that: include: A cylinder, the outer wall of which is wrapped with a heating layer; A piston, the piston being disposed at one end of the cylinder and being configured to be able to move forward and backward freely relative to the cylinder in a manner that the outer peripheral surface is in sliding contact with the inner peripheral surface of the cylinder; A porous cylinder head, which is arranged at the other end of the cylinder body and is provided with a liquid inlet hole, a gas inlet hole and a gas outlet hole located on the same circumference; A three-way valve, which is arranged at the front end of the porous cartridge head and has a flow hole thereon; and the three-way valve can rotate relative to the porous cartridge head, and driven by the rotation of the three-way valve, the liquid inlet hole is connected to the flow hole, or the gas inlet hole is connected to the flow hole, or the gas outlet hole is connected to the flow hole; A pipe joint is arranged at the front end of the three-way valve and is connected and docked with the flow hole of the three-way valve.

2. The portable gas distribution device according to claim 1, characterized in that: The inner wall of the cylinder is treated with inertization.

3. The portable gas distribution device according to claim 1 or 2, characterized in that: The outer wall of the cylinder is provided with volume scale marks, the outer wall of the cylinder at the corresponding position of the volume scale marks is not wrapped with the heating layer, a recess is formed on the cylinder, and the piston is fixedly connected with a metering rod that cooperates with the recess on the cylinder.

4. The portable gas distribution device according to claim 1 or 2, characterized in that: The heating layer is provided with a temperature control device, which can control the temperature and vaporize the liquid in the gas distribution chamber; The outer side of the heating layer is wrapped with a heat insulating shell.

5. The portable gas distribution device according to claim 1 or 2, characterized in that: A sealing gasket is arranged in the liquid sampling port on the porous cartridge head, and a one-way valve is arranged in the gas sampling hole and the gas sampling outlet hole.

6. The portable gas distribution device according to claim 1 or 2, characterized in that: The three-way valve and the porous cylinder head are both disc-shaped, and the three-way valve and the porous cylinder head are sealed by an O-ring.

7. The portable gas distribution device according to claim 1 or 2, characterized in that: The outer surface of the pipe joint is provided with an external thread structure; A sealing ring is arranged on the inner side of the pipe joint.

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