Portable VOCs enrichment and analysis device and portable chromatographic equipment
By adopting a stepped semiconductor refrigeration unit and thermal block design in the portable VOCs enrichment analysis device, the problem of poor cooling effect of the refrigeration module is solved, efficient VOCs enrichment and low concentration detection are achieved, equipment maintenance is simplified, and suitable for Portable gas chromatography equipment.
Patent Information
- Application Number
- CN202411524557.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2025-01-07
AI Technical Summary
The cooling effect of the existing portable VOCs enrichment analysis device is poor, resulting in low VOCs enrichment efficiency and difficult to achieve accurate detection at low concentrations. Laboratory-level equipment has complex structure, large volume, high power consumption and high price. , not suitable for portable gas chromatography equipment.
The semiconductor refrigeration sheets arranged in at least four layers are formed into a stepped refrigeration unit, combining the thermal blocks and spacers to achieve higher refrigeration temperature and more uniform cooling capacity transmission, and improve the convenience of replacement and airtightness of the enrichment tube.
Low temperature refrigeration at -40°C is achieved, which improves the enrichment efficiency of VOCs and the accuracy of low concentration detection, simplifies the replacement process of enrichment tubes, reduces maintenance costs, and makes the device more portable and efficient.
Smart Images
Figure CN119269215A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of enrichment and analysis devices, and in particular to a portable VOCs enrichment and analysis device and a portable chromatography device. Background Art
[0002] The VOCs (volatile organic compounds) content in the ambient air of the car is as low as ppb level, but it has potential harm to human health. For example, formaldehyde and benzene are listed as Class I carcinogens by the WHO, and their detection is very necessary. Direct detection of low-concentration VOCs using portable gas chromatography, mass spectrometry and other analytical instruments often cannot achieve the required detection sensitivity and accuracy. Therefore, it is necessary to use enrichment technology to increase the concentration of VOCs in the sample, thereby improving the detection sensitivity of the equipment and reducing signal noise.
[0003] Low-temperature adsorption is a commonly used enrichment technology. The portable VOCs enrichment and analysis device of the related technology is limited by volume, and the cooling effect of the refrigeration module is poor. The lowest temperature can usually only reach about -10°C. The enrichment efficiency of VOCs is poor, and the detection accuracy is difficult to guarantee at low concentrations. The ultra-low-temperature enrichment device equipped with laboratory-grade gas chromatography equipment has a complex structure, large size, high power consumption and high price, and is not suitable for portable gas chromatography equipment.
[0004] Therefore, how to provide a portable VOCs enrichment and analysis device and a portable chromatography equipment to improve the enrichment efficiency of VOCs and improve the detection accuracy at low concentrations has become a technical problem that technical personnel in this field urgently need to solve. Summary of the invention
[0005] The purpose of this application is to provide a portable VOCs enrichment and analysis device and a portable chromatography equipment to improve the enrichment efficiency of VOCs, improve the detection accuracy at low concentrations, and improve the convenience of replacing the enrichment tube and the air tightness.
[0006] In order to solve the above technical problems, the present application provides a portable VOCs enrichment and analysis device, comprising:
[0007] A cold trap body, wherein the cold trap body has a chamber inside;
[0008] an enrichment tube installed inside the chamber;
[0009] A heat-conducting block, wherein the heat-conducting block is sleeved on the outer circumference of the enrichment tube and covers a partial area of the enrichment tube in the axial direction;
[0010] A refrigeration unit, comprising at least four layers of stacked semiconductor refrigeration sheets, wherein the area of the large surface of each semiconductor refrigeration sheet gradually decreases in the direction close to the heat conductive block, the refrigeration unit forms a refrigeration surface facing the wall surface of the heat conductive block, the refrigeration unit is installed inside the chamber, and the refrigeration surface is in contact with the outer surface of the heat conductive block;
[0011] The cold trap body comprises a main body and a cover plate, the upper end of the main body has an open end, the cover plate is detachably connected to the upper end of the main body and blocks the open end, and the main body and the cover plate enclose the chamber;
[0012] The heat conductive block includes two split parts, and the two split parts are buckled and wrapped around the enrichment tube in the up and down directions. The portable VOCs enrichment and analysis device also includes two air supply units, and the air supply unit includes a sealing joint, a connecting gas column and a connecting head. The sealing joint is installed on the cold trap body and is located at both ends of the enrichment tube. The outer end of the connecting gas column and the connecting head are detachably connected, and the connecting gas column and the connecting head are slidably inserted into the sealing joint, and the connecting gas column and the enrichment tube are detachably connected.
[0013] The portable VOCs enrichment and analysis device of this embodiment adopts a refrigeration unit for refrigeration, wherein the refrigeration unit includes at least four layers of semiconductor refrigeration plates arranged in a stacked manner. The stacked arrangement mentioned here means that at least four layers of semiconductor refrigeration plates are arranged in sequence in a direction perpendicular to the large surface, and the area of the large surface of each semiconductor refrigeration plate gradually decreases in the direction close to the heat conductive block, so that the refrigeration unit forms a stepped structure. The stepped structure makes the power density of the refrigeration surface higher, the temperature difference of the refrigeration unit along the stacking direction is larger, and the refrigeration temperature reached by the refrigeration surface is lower. The measured temperature of the refrigeration surface can reach as low as -40°C. The heat conductive block evenly transfers the cold generated by the refrigeration unit to the enrichment tube, so that the ambient air in the vehicle entering the enrichment tube is cooled, and the VOCs gas in the ambient air in the vehicle is enriched in the enrichment tube, thereby improving the enrichment efficiency of the VOCs gas and the detection accuracy at low concentrations. In addition, the convenience of replacement and air tightness of the enrichment tube are improved through structural design.
[0014] Optionally, a spacer is further included, which is pressed between the outer surface of the heat conductive block facing away from the refrigeration unit and the cold trap body, and the contact area between the spacer and the cold trap body is smaller than the area of the outer surface of the heat conductive block facing away from the refrigeration unit.
[0015] Optionally, it further includes a heat conductive block pressing plate, which is connected to the inner surface of the cold trap body, and a receiving groove is provided on the wall surface of the heat conductive block pressing plate facing the refrigeration unit, and the spacer is partially connected inside the receiving groove.
[0016] Optionally, the refrigeration surface fits the lower surface of the split portion at the lower end, and the split portion at the upper end and the enrichment tube can pass through the open end.
[0017] Optionally, it also includes two connecting nuts and two connecting ferrules, the two connecting nuts are mounted on the enrichment tube and are located at both ends of the enrichment tube, the two connecting ferrules are mounted on the enrichment tube and are located inside the corresponding connecting nuts, the connecting nuts are threadedly connected to the corresponding gas supply unit, and the connecting nuts and the connecting ferrules are made of flexible material.
[0018] Optionally, a heating wire and a temperature sensor are further included, wherein the heating wire is wound around the outer circumference of the enrichment tube, and the heating wire and the heat conductive block are both in contact with the temperature sensor.
[0019] Optionally, a heat dissipation unit is further included, which includes a heat sink and a heat dissipation fan. The heat sink is connected to the cold trap body, and the wall of the refrigeration unit facing away from the heat conductive block forms a heat dissipation surface. The heat sink is in contact with the heat dissipation surface, and the heat dissipation fan is connected to one end of the heat sink away from the refrigeration unit.
[0020] Optionally, a side wall of the cold trap body is provided with a purge port, and the purge port is connected to the chamber.
[0021] This embodiment also provides a portable chromatography device, including a device body and the aforementioned portable VOCs enrichment and analysis device, wherein the portable VOCs enrichment and analysis device is installed on the device body.
[0022] The portable chromatography equipment of this embodiment includes the aforementioned portable VOCs enrichment and analysis device, and therefore has the same technical effects as the aforementioned portable VOCs enrichment and analysis device, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 This is a structural schematic diagram of a specific embodiment of the portable VOCs enrichment and analysis device provided in this application;
[0024] Figure 2 for Figure 1 Schematic diagram of the partial structure of the portable VOCs enrichment and analysis device from another angle;
[0025] Figure 3 for Figure 1 A partial enlarged image of area A in the portable VOCs enrichment and analysis device;
[0026] in, Figure 1-Figure 3 The reference numerals in the figures are as follows:
[0027] 1-cold trap body; 1A-main body; 1B-cover plate; 1a-chamber; 1b-purge port;
[0028] 2- Enrichment tube;
[0029] 3-heat conducting block; 31-split part;
[0030] 4-refrigeration unit; 41-semiconductor refrigeration chip; 4A-refrigeration surface; 4B-heat dissipation surface;
[0031] 5- Spacer;
[0032] 6-heat conducting block pressing plate; 6a-accommodating groove;
[0033] 7-air supply unit; 71-sealing joint; 72-connecting gas column; 73-connecting head;
[0034] 81-connecting nut; 82-connecting ferrule;
[0035] 9- heating wire;
[0036] 10- Temperature sensor;
[0037] 11- cooling unit; 111- heat sink; 112- cooling fan;
[0038] 12-Needle shaft. DETAILED DESCRIPTION
[0039] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments.
[0040] Herein, the direction close to the interior of the cold trap body 1 is “inside”, and the direction away from the interior of the cold trap body 1 is “outside”; herein, the extending direction of the enrichment tube 2 is “axial”.
[0041] Please refer to Figure 1-Figure 3 , Figure 1 This is a structural schematic diagram of a specific embodiment of the portable VOCs enrichment and analysis device provided in this application; Figure 2 for Figure 1 Schematic diagram of the partial structure of the portable VOCs enrichment and analysis device from another angle; Figure 3 for Figure 1 A partial enlarged image of area A in the portable VOCs enrichment and analysis device.
[0042] This embodiment provides a portable VOCs enrichment and analysis device, including:
[0043] A cold trap body 1, wherein the cold trap body 1 has a chamber 1a therein;
[0044] Enrichment tube 2, which is installed inside chamber 1a;
[0045] A heat conducting block 3, which is sleeved on the outer periphery of the enrichment tube 2 and covers a partial area of the enrichment tube 2 in the axial direction;
[0046] The refrigeration unit 4 includes at least four layers of stacked semiconductor refrigeration plates 41. The large surface area of each semiconductor refrigeration plate 41 gradually decreases along the direction approaching the heat conductive block 3. The refrigeration unit 4 forms a refrigeration surface 4A facing the wall surface of the heat conductive block 3. The refrigeration unit 4 is installed inside the chamber 1a, and the refrigeration surface 4A is in contact with the outer surface of the heat conductive block 3.
[0047] The portable VOCs enrichment and analysis device of this embodiment adopts a refrigeration unit 4 for refrigeration, wherein the refrigeration unit 4 includes at least four layers of semiconductor refrigeration sheets 41 stacked in layers. The stacked arrangement here means that at least four layers of semiconductor refrigeration sheets 41 are arranged in sequence in a direction perpendicular to the large surface. In the direction close to the heat conductive block 3, the large surface area of each semiconductor refrigeration sheet 41 gradually decreases, so that the refrigeration unit 4 forms a Figure 1 The stepped structure (pagoda-shaped structure) shown in the figure makes the power density of the cooling surface 4A higher, the temperature difference of the cooling unit 4 along the stacking direction larger, and the cooling temperature reached by the cooling surface 4A lower. The measured temperature of the cooling surface 4A can reach as low as -40°C. The heat conducting block 3 evenly transfers the cold energy generated by the cooling unit 4 to the enrichment tube 2, so that the ambient air in the vehicle entering the enrichment tube 2 is cooled, and the VOCs gas in the ambient air in the vehicle is enriched in the enrichment tube 2, thereby improving the enrichment efficiency of the VOCs gas and improving the detection accuracy at low concentrations.
[0048] In this embodiment, the heat conducting block 3 is made of aluminum, which has good thermal conductivity and light weight, and is suitable for portable VOCs enrichment and analysis devices. In other embodiments of the present application, the heat conducting block 3 can also be made of pure copper or other metal or non-metal materials with good thermal conductivity.
[0049] Please continue to refer to 1 and Figure 2 In this embodiment, the portable VOCs enrichment and analysis device also includes a spacer 5, which is pressed between the outer surface of the heat conductive block 3 facing away from the refrigeration unit 4 and the cold trap body 1, and the contact area between the spacer 5 and the cold trap body 1 is smaller than the area of the outer surface of the heat conductive block 3 facing away from the refrigeration unit 4.
[0050] It can be understood that if the above spacer 5 is not provided, the outer surface of the heat conductive block 3 facing away from the refrigeration unit 4 directly contacts the cold trap body 1, and the contact area between the heat conductive block 3 and the cold trap body 1 is large, which may cause heat loss due to solid contact heat conduction. In this embodiment, a spacer 5 is additionally provided, and the spacer 5 is pressed between the outer surface of the heat conductive block 3 facing away from the refrigeration unit 4 and the cold trap body 1. On the one hand, the spacer 5 and the refrigeration unit 4 work together to fix the heat conductive block 3. On the other hand, the spacer 5 separates the heat conductive block 3 from the cold trap body 1. The contact area between the spacer 5 and the cold trap body 1 is smaller than the area of the outer surface of the heat conductive block 3 facing away from the refrigeration unit 4, which can reduce the cold loss caused by solid contact heat conduction and improve the cooling rate.
[0051] Depend on Figure 2 It can be seen that in this embodiment, the spacer 5 is in the form of a coil spring structure, and the coil spring can be subjected to axial compression, so that the heat conducting block 3 is always subjected to the elastic pressing force of the coil spring, thereby improving the installation stability of the heat conducting block 3.
[0052] In some other embodiments of the present application, the spacer 5 can be made of a flexible material, such as nylon, rubber, etc.
[0053] Please continue to refer to Figure 1 and Figure 2 In this embodiment, the portable VOCs enrichment and analysis device also includes a heat-conducting block pressing plate 6, which is connected to the inner surface of the cold trap body 1. The wall surface of the heat-conducting block pressing plate 6 facing the refrigeration unit 4 is provided with a receiving groove 6a, and the spacer 5 is partially connected inside the receiving groove 6a.
[0054] In this way, firstly, the accommodating groove 6a can limit the spacer 5, thereby improving the connection reliability between the spacer 5 and the cold trap body 1; secondly, the accommodating groove 6a can also play a guiding role. For example, when the spacer 5 is a coil spring, the accommodating groove 6a allows the coil spring to be axially compressed only under the action of the heat conductive block pressure plate 6 and the refrigeration unit 4, thereby reducing the possibility of other deformations of the coil spring except axial compression.
[0055] Depend on Figure 2 It can be seen that in the present embodiment, the heat conductive block pressing plate 6 and the cold trap body 1 are split structures, and the heat conductive block pressing plate 6 is installed on the cold trap body 1 by threaded connectors such as screws, etc., which facilitates the separate molding of the heat conductive block pressing plate 6 and the cold trap body 1, and the installation and disassembly of the heat conductive block pressing plate 6 and the cold trap body 1 are also more convenient.
[0056] In some embodiments of the present application, the heat conducting block pressing plate 6 and the cold trap body 1 are separate structures and are fixed by bonding, which also facilitates the separate molding of the heat conducting block pressing plate 6 and the cold trap body 1.
[0057] In some other embodiments of the present application, the heat-conducting block pressing plate 6 and the cold trap body 1 are integrally formed, the structure is reliable, and no separate fixing step is required, thereby improving assembly efficiency.
[0058] It can be understood that the enrichment tube 2, as a detection consumable, needs to be replaced in time to ensure the accuracy of the equipment detection when it reaches the end of its service life or is contaminated by the sample. The portable VOCs enrichment and analysis device of the related technology has a complex structural design and requires professional engineers to replace the analysis tube, which has high maintenance costs.
[0059] Based on this, please continue to refer to Figure 1 In this embodiment, the cold trap body 1 includes a main body 1A and a cover plate 1B. The upper end of the main body 1A has an open end. The cover plate 1B is detachably connected to the upper end of the main body 1A and blocks the open end. The main body 1A and the cover plate 1B enclose the aforementioned chamber 1a.
[0060] The heat conducting block 3 includes two split parts 31, and the two split parts 31 are buckled and wrapped around the enrichment tube 2 in the up-down direction. The portable VOCs enrichment and analysis device also includes two air supply units 7, which are installed on the cold trap body 1. The two air supply units 7 are located at the axial ends of the enrichment tube 2, and the air supply units 7 and the enrichment tube 2 are detachably connected;
[0061] The cooling surface 4A is in contact with the lower surface of the split portion 31 at the lower end, and the split portion 31 and the enrichment tube 2 at the upper end can pass through the opening end at the upper end of the main body 1A.
[0062] As set above, in this embodiment, the cold trap body 1 adopts a split structure arranged up and down, the heat conducting block 3 also adopts a split structure arranged up and down, the gas supply unit 7 and the enrichment pipe 2 are detachably connected, and when the enrichment pipe 2 needs to be replaced, the cover plate 1B can be disassembled first, thereby opening the open end of the upper end of the main body 1A, and loosening the heat conducting block 3, and then, the split part 31 at the upper end is disassembled from the open end, and then the connection between the gas supply unit 7 and the enrichment pipe 2 is released, and the enrichment pipe 2 can be directly removed from the upper end of the main body 1A. The open end is taken out to complete the disassembly of the enrichment tube 2; then, a new enrichment tube 2 is installed. Specifically, the new enrichment tube 2 is first supported on the split portion 31 at the lower end, and then the enrichment tube 2 and the gas supply unit 7 are connected, and then the split portion 31 at the upper end and the split portion 31 at the lower end are buckled together so that the two wrap the enrichment tube 2, and finally the cover plate 1B is connected to the upper end of the main body 1A, and the open end is sealed, and the spacer 5 presses the split portion 31 at the upper end to fix the heat conductive block 3 and the enrichment tube 2, thereby completing the replacement of the enrichment tube 2.
[0063] It can be seen that according to the arrangement of this embodiment, the enrichment tube 2 can be easily detached from the open end of the upper end of the main body 1A. When the portable VOCs enrichment and analysis device is installed on the portable chromatographic detection equipment, the installation and disassembly of the enrichment tube 2 can be completed without taking out the portable VOCs enrichment and analysis device. The replacement operation steps of the enrichment tube 2 are simple, and non-professionals can operate the replacement, which reduces the maintenance cost and service life of the equipment.
[0064] In this embodiment, the cover plate 1B is made of a transparent material, such as a transparent acrylic plate, so that an operator can intuitively observe the internal state of the cold trap body 1 from the outside.
[0065] In this embodiment, the main body 1A is made of a material with good thermal insulation effect, including but not limited to nylon.
[0066] It can be understood that the aforementioned heat conductive block pressing plate 6 is connected to the inner wall of the cover plate 1B. Therefore, the heat conductive block pressing plate 6 can also play a shielding role on the spacer 5 to prevent the spacer 5 from being exposed, thereby improving the consistency and sophistication of the portable VOCs enrichment and analysis device of this embodiment.
[0067] Please continue to refer to Figure 1 In this embodiment, the portable VOCs enrichment and analysis device also includes two connecting nuts 81 and two connecting ferrules 82. The two connecting nuts 81 are mounted on the enrichment tube 2 and are located at both ends of the enrichment tube 2. The two connecting ferrules 82 are mounted on the enrichment tube 2 and are located inside the corresponding connecting nuts 81. The connecting nuts 81 are threadedly connected to the corresponding air supply unit 7. The connecting nuts 81 and the connecting ferrules 82 are made of flexible material.
[0068] Thus, in the present embodiment, the enrichment tube 2 is connected to the corresponding gas supply unit 7 via the connecting nut 81. When in use, the connection between the enrichment tube 2 and the gas supply unit 7 can be released by directly twisting the connecting nut 81, so that the disassembly and replacement of the enrichment tube 2 is more convenient; the provision of the connecting ferrule 82 can improve the connection reliability between the enrichment tube 2 and the gas supply unit 7; at the same time, the connecting nut 81 and the connecting ferrule 82 are made of a flexible material, which can improve the air tightness between the enrichment tube 2 and the gas supply unit 7 during contact, avoid gas leakage, and improve the detection accuracy; in addition, the connecting nut 81 and the connecting ferrule 82 are made of a flexible material, which can prevent the enrichment tube 2 from being crushed when impacted, thereby improving the service life of the enrichment tube 2.
[0069] In this embodiment, the material of the connecting nut 81 and the connecting ferrule 82 includes but is not limited to polytetrafluoroethylene. Polytetrafluoroethylene has the advantages of high temperature resistance, low temperature resistance, corrosion resistance, high lubricity, non-adhesion, non-toxicity, good electrical insulation performance and anti-aging, and is more suitable for enrichment and analysis devices.
[0070] Please continue to refer to Figure 1In this embodiment, the gas supply unit 7 includes a sealing joint 71, a connecting gas column 72 and a connecting head 73. The sealing joint 71 is installed on the cold trap body 1 and is located at both ends of the enrichment pipe 2. The outer end of the connecting gas column 72 and the connecting head 73 are detachably connected. The connecting gas column 72 and the connecting head 73 are slidably penetrated through the sealing joint 71, and the connecting gas column 72 and the enrichment pipe 2 are detachably connected.
[0071] As configured above, the connecting gas column 72 and the connecting head 73 are slidably inserted into the sealing joint 71, and an axially retractable structure is formed between the sealing joint 71, the connecting gas column 72 and the connecting head 73. The connecting gas column 72 slides axially inward to connect with the corresponding end of the enrichment tube 2, so that the gas supply unit 7 and the enrichment tube 2 are connected. The connecting gas column 72 slides axially outward to release the connection with the corresponding end of the enrichment tube 2, so that the gas supply unit 7 and the enrichment tube 2 are disconnected, making the enrichment and analysis device of this embodiment easier to disassemble and replace the enrichment tube 2; at the same time, the setting of the sealing joint 71 can ensure the airtightness of the connection between the gas supply unit 7 and the cold trap body 1, so that external water vapor is not easy to enter the interior of the chamber 1a and cause ice formation, which is beneficial to further improve the service life of the enrichment and analysis device of this embodiment.
[0072] As can be seen from the foregoing, the connecting gas column 72 can be detachably connected to the enrichment tube 2 via the connecting nut 81 .
[0073] Among them, the connecting gas column 72 can slide axially outward by either manually dragging the connecting gas column 72 outward by the operator, or adding a reset spring, the reset spring is mounted on the connecting head 73, the outer end of the connecting head 73 has a limiting portion, and the reset spring is axially pressed between the limiting portion and the outer end wall of the cold trap body 1. When the connecting gas column 72 slides axially inward and connects with the connecting nut 81 at the corresponding end, the reset spring is in a compressed energy storage state. When the connecting gas column 72 is released from the connecting nut 81 at the corresponding end, the connecting gas column 72 and the connecting head 73 can slide outward under the restoring force of the reset spring, and the operator does not need to manually drag the connecting gas column 72 outward, which is convenient to operate.
[0074] In this embodiment, the sealing joint 71 is fixed to the cold trap body 1 by means of threaded connectors such as screws, etc., so as to improve the installation stability of the sealing joint 71 .
[0075] Depend on Figure 1 and Figure 3 It can be seen that in this embodiment, the cold trap body 1 has a mounting hole for installing the sealing joint 71, and a threaded connection hole. The threaded connection hole and the mounting hole are connected. The mounting hole passes through the outer end wall of the cold trap body 1. The sealing joint 71 can be installed from the outside of the cold trap body 1 into the inside of the mounting hole, and then connected to the cold trap body 1 through a threaded connection.
[0076] At the same time, the axial outer end of the sealing joint 71 has an extension portion extending radially toward the interior of the sealing joint 71, and the extension portion can limit the connecting gas column 72. When the connecting gas column 72 and the inner wall of the extension portion collide, the connecting gas column 72 cannot continue to move outward, thereby preventing the connecting gas column 72 and the connecting head 73 from falling off.
[0077] In this embodiment, the connecting gas column 72 and the connecting head 73 are split structures, and the two are connected by threads. In this way, different connecting gas columns 72 or connecting heads 73 can be replaced according to the connection requirements. The connecting gas column 72 and the connecting head 73 can adopt the same or different size specifications. For example, the connecting gas column 72 can adopt a 1 / 8 interface tube, and the connecting head 73 can adopt a 1 / 16 interface tube, so that the enrichment and analysis device of this embodiment is more adaptable.
[0078] Please continue to refer to Figure 1 In this embodiment, the portable VOCs enrichment and analysis device also includes a heating wire 9, which is wound around the outer periphery of the enrichment tube 2 and is located between the outer peripheral wall of the enrichment tube 2 and the inner peripheral wall of the heat conductive block 3, and is used to heat the enrichment tube 2, thereby analyzing the VOCs gas enriched in the enrichment tube 2.
[0079] Furthermore, in this embodiment, the portable VOCs enrichment and analysis device also includes a temperature sensor 10 , and the heating wire 9 and the heat conductive block 3 are both attached to the temperature sensor 10 .
[0080] In this way, the temperature sensor 10 can measure the temperature of the heating wire 9 and the heat conductive block 3. When enriching VOCs gas, the refrigeration temperature of the heat conductive block 3 can be accurately controlled through the detection result of the temperature sensor 10, and the time delay of temperature detection during refrigeration can be reduced, thereby ensuring the enrichment efficiency of VOCs gas; when analyzing the VOCs gas enriched in the enrichment tube 2, the heating temperature of the heating wire 9 can be accurately controlled through the temperature sensor 10, and the enrichment tube 2 can be quickly heated by the heating wire 9, thereby reducing the time delay of temperature detection during heating, thereby quickly and efficiently analyzing the VOCs gas enriched in the enrichment tube 2.
[0081] In this embodiment, the temperature sensor 10 may be a PT100 sensor with high measurement accuracy and stable performance.
[0082] In this embodiment, the cold trap body 1 is provided with a pin seat and also includes a needle shaft 12. The outer end of the needle shaft 12 is connected to a 24V voltage. The needle shaft 12 passes through the pin seat from the outside to the inside and contacts the heating wire 9 to ensure that the current of the heating wire 9 can be output stably and continuously.
[0083] Please continue to refer to Figure 1In this embodiment, the portable VOCs enrichment and analysis device also includes a heat dissipation unit 11, and the heat dissipation unit 11 includes a heat sink 111 and a heat dissipation fan 112. The heat sink 111 is connected to the cold trap body 1, and the wall of the refrigeration unit 4 facing away from the heat conduction block 3 forms a heat dissipation surface 4B. One end of the heat sink 111 is in contact with the heat dissipation surface 4B, and the heat dissipation fan 112 is connected to the end of the heat sink 111 away from the refrigeration unit 4.
[0084] In this way, after the VOCs gas enriched in the enrichment tube 2 is analyzed, the cooling fan 112 can be used to cool the heat sink 111 to dissipate the heat generated by the heat dissipation surface 4B of the refrigeration unit 4, thereby ensuring that the refrigeration unit 4 works efficiently and the temperature of the heat conductive block 3 and the enrichment tube 2 is quickly reduced to the required temperature; at the same time, the refrigeration unit 4 and the cooling fan 112 are located at opposite ends of the heat sink 111. In other words, the refrigeration unit 4, the heat sink 111 and the cooling fan 112 are located on the same straight line, and the gas flow path is the shortest. By adjusting the cooling fan 112 to a suitable height, the airflow is smooth, which is conducive to further improving the heat dissipation efficiency.
[0085] In some embodiments of the present application, the heat sink 111 is connected to the cold trap body 1 by threaded connectors such as bolts, and the cooling fan 112 is connected to the heat sink 111 by threaded connectors such as bolts. The connection is reliable and easy to disassemble, and it is easy to replace the heat sink 111 and the cooling fan 112 of different specifications according to actual temperature requirements.
[0086] In practice, the cooling fan 112 may be a silent fan to reduce operating noise and improve user experience.
[0087] Please continue to refer to Figure 1 In this embodiment, a purge port 1b is provided on the side wall of the cold trap body 1, and the purge port 1b is connected to the chamber 1a.
[0088] In this way, the purge port 1b can be connected to an external purge gas source, and the external purge gas source continuously passes dry purge gas into the interior of the chamber 1a to keep the pressure inside the chamber 1a higher than that outside, thereby blocking external water vapor from entering the chamber 1a, making it difficult for the surface of the heat conductive block 3 to freeze, thereby increasing the service life of the semiconductor refrigeration plate 41.
[0089] Through the above structural optimization design, the overall size of the portable VOCs enrichment and analysis device of this embodiment is only 120mm*50mm*72mm, which is smaller than the same type of enrichment and analysis devices. The miniaturized structural design makes it more widely applicable in portable chromatographic detection equipment; and after testing, after the enrichment and analysis device is started in a room temperature environment of 25°C, the temperature can be stably reduced to -40°C within 2 minutes, and low-concentration VOCs in the ambient air in the vehicle can be quickly and efficiently enriched.
[0090] This embodiment also provides a portable chromatography device, including the aforementioned portable VOCs enrichment and analysis device.
[0091] The portable chromatography equipment of this embodiment includes the aforementioned portable VOCs enrichment and analysis device, and therefore has the same technical effects as the aforementioned portable VOCs enrichment and analysis device, which will not be repeated here.
[0092] The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.
Claims
1. A portable VOCs enrichment and analysis device, characterized in that: include: A cold trap body (1), wherein the cold trap body (1) has a chamber (1a) inside; an enrichment tube (2), the enrichment tube (2) being installed inside the chamber (1a); A heat conducting block (3), the heat conducting block (3) being sleeved on the outer circumference of the enrichment tube (2) and covering a partial area of the enrichment tube (2) in the axial direction; A refrigeration unit (4) comprising at least four layers of semiconductor refrigeration sheets (41) stacked in layers, wherein the area of the larger surface of each semiconductor refrigeration sheet (41) gradually decreases in a direction approaching the heat conductive block (3), and the refrigeration unit (4) forms a refrigeration surface (4A) facing the wall surface of the heat conductive block (3). The refrigeration unit (4) is installed inside the chamber (1a), and the refrigeration surface (4A) is in contact with the outer surface of the heat conductive block (3); The cold trap body (1) comprises a main body (1A) and a cover plate (1B); the upper end of the main body (1A) has an open end; the cover plate (1B) is detachably connected to the upper end of the main body (1A) and blocks the open end; the main body (1A) and the cover plate (1B) enclose the chamber (1a); The heat conducting block (3) comprises two split parts (31), the two split parts (31) being buckled and wrapped around the enrichment tube (2) in the up-down direction. The portable VOCs enrichment and analysis device further comprises two air supply units (7), the air supply units (7) comprising a sealing joint (71), a connecting air column (72) and a connecting head (73). The sealing joint (71) is installed on the cold trap body (1) and is located at both ends of the enrichment tube (2). The outer end of the connecting air column (72) and the connecting head (73) are detachably connected. The connecting air column (72) and the connecting head (73) are slidably inserted into the sealing joint (71), and the connecting air column (72) and the enrichment tube (2) are detachably connected.
2. The portable VOCs enrichment and analysis device according to claim 1, characterized in that: It also comprises a spacer (5), the spacer (5) being pressed between the outer surface of the heat conductive block (3) facing away from the refrigeration unit (4) and the cold trap body (1), and the contact area between the spacer (5) and the cold trap body (1) being smaller than the area of the outer surface of the heat conductive block (3) facing away from the refrigeration unit (4).
3. The portable VOCs enrichment and analysis device according to claim 2, characterized in that: It also comprises a heat-conducting block pressing plate (6), the heat-conducting block pressing plate (6) being connected to the inner surface of the cold trap body (1), a wall surface of the heat-conducting block pressing plate (6) facing the refrigeration unit (4) being provided with a receiving groove (6a), and the spacer (5) is partially connected inside the receiving groove (6a).
4. The portable VOCs enrichment and analysis device according to any one of claims 1 to 3, characterized in that: The refrigeration surface (4A) is in contact with the lower surface of the split portion (31) located at the lower end, and the split portion (31) located at the upper end and the enrichment tube (2) can pass through the open end.
5. The portable VOCs enrichment and analysis device according to claim 4, characterized in that: It also includes two connecting nuts (81) and two connecting ferrules (82), wherein the two connecting nuts (81) are fitted onto the enrichment tube (2) and are located at both ends of the enrichment tube (2), and the two connecting ferrules (82) are fitted onto the enrichment tube (2) and are located inside corresponding connecting nuts (81), wherein the connecting nuts (81) can be threadedly connected to or disconnected from the corresponding gas supply unit (7), and the connecting nuts (81) and the connecting ferrules (82) are made of flexible material.
6. The portable VOCs enrichment and analysis device according to any one of claims 1 to 3, characterized in that: It also includes a heating wire (9) and a temperature sensor (10), wherein the heating wire (9) is wound around the outer circumference of the enrichment tube (2), and the heating wire (9), the heat conducting block (3) and the temperature sensor (10) are all in contact with each other.
7. The portable VOCs enrichment and analysis device according to any one of claims 1 to 3, characterized in that: It also comprises a heat dissipation unit (11), the heat dissipation unit (11) comprising a heat sink (111) and a heat dissipation fan (112), the heat sink (111) being connected to the cold trap body (1), the wall surface of the refrigeration unit (4) facing away from the heat conduction block (3) forming a heat dissipation surface (4B), the heat sink (111) and the heat dissipation surface (4B) being in close contact with each other, and the heat dissipation fan (112) being connected to one end of the heat sink (111) away from the refrigeration unit (4).
8. The portable VOCs enrichment and analysis device according to any one of claims 1 to 3, characterized in that: A purge port (1b) is provided on the side wall of the cold trap body (1), and the purge port (1b) is connected to the chamber (1a).
9. A portable chromatography device, characterized in that: It comprises a device body, and the portable VOCs enrichment and analysis device according to any one of claims 1 to 8, wherein the portable VOCs enrichment and analysis device is installed on the device body.