A quick seal chromatographic column connection device for gas chromatographs

Abstract

The utility model provides a kind of for fast sealing chromatographic column connecting device of gas chromatograph, it is related to gas chromatograph chromatographic column connecting technical field, including the sample inlet and detector being connected with the both ends of capillary column respectively, further including the joint body being connected with the sample inlet in one end;2 head multiple thread is used in the present application, locking sleeve and joint body only need 1~2 circles to complete locking / separation, cooperate lateral slotted transverse separation design, single chromatographic column dismounting time consumption is less than or equal to 2 minutes, compared with traditional device efficiency is significantly improved;And installation handle is with antiskid line, whole process does not need tool, reduces operation threshold.

Description

Technical Field

[0001] This utility model relates to the field of gas chromatograph column connection technology, and more specifically, to a rapid sealing column connection device for gas chromatographs. Background Technology

[0002] Gas chromatographs are core analytical instruments in the field of modern analytical chemistry, and are widely used in environmental monitoring, food safety, pharmaceuticals, petrochemicals and other fields. Their analytical accuracy and reliability directly depend on the quality of the connection and sealing between the core components, the chromatographic column, the injection port and the detector.

[0003] Currently, the connection between gas chromatograph columns (especially capillary columns) and the instrument body generally adopts the traditional "nut-pressure ring-graphite washer" threaded connection method: tightening the nut compresses the graphite washer, causing it to deform and fill the gap between the capillary column and the connector, thus achieving a seal. However, this traditional connection method has many intractable technical drawbacks, specifically as follows: 1. The operation process is cumbersome and highly dependent on the operator's experience: When installing and replacing the chromatographic column, the nut and graphite washer must be put on the chromatographic column in sequence, the two ends of the chromatographic column must be cut flat, the chromatographic column is then inserted into the injection port and the insertion depth is repeatedly adjusted. Then, the nut is first tightened by hand until it cannot be turned, and then an additional 1 / 4 to 1 / 2 turn is tightened with a wrench to ensure the degree of sealing. The whole process requires the use of special tools, the steps are cumbersome and the tightening torque depends entirely on the operator's experience. Insufficient torque can easily lead to air leakage, while excessive torque can crush the graphite washer or even damage the end face of the chromatographic column. 2. Unstable sealing effect and poor repeatability: Traditional graphite gaskets are brittle, easily broken and have poor resilience. The amount of compression deformation after each disassembly and reinstallation is difficult to keep consistent, resulting in significant differences in sealing effect, which directly affects the reproducibility of gas chromatography analysis results. At the same time, the fit clearance between the graphite gasket and the chromatographic column and connectors is not precisely controlled, which further aggravates the fluctuation of sealing performance. 3. Extremely low work efficiency: The entire process of traditional connection method (including column cutting, depth adjustment, multiple tightening of nuts, and sealing test) usually takes 30 to 40 minutes. In scenarios such as food testing and environmental monitoring where different specifications of chromatographic columns need to be changed frequently, this greatly reduces the overall analytical efficiency of the laboratory. In addition, the graphite gasket is a single-use consumable part, and the nut is also prone to stripping and deformation due to repeated tightening, which requires regular replacement, increasing the cost of use and downtime. Therefore, there is an urgent need in the existing technology for a gas chromatograph column connection device that is easy to operate, requires no special tools, and has stable sealing performance, in order to solve the core problems of low efficiency, poor sealing and easy damage of graphite gaskets in traditional connection methods. Utility Model Content

[0004] The purpose of this invention is to solve the problems mentioned in the background art and to propose a rapid sealing column connection device for gas chromatographs.

[0005] The technical solution adopted by this utility model to solve its technical problem is: A rapid-sealing column connection device for a gas chromatograph includes an injection port and a detector respectively connected to both ends of a capillary column, and a connector body with one end connected to either the injection port or the detector. The connector body has a first through hole that allows the capillary column to pass through; The locking sleeve has a storage groove at one end near the connector body and a fastening groove at the other end away from the connector body. The storage groove has an internal thread, and the connector body has an external thread that mates with the internal thread. The fastening groove has a fixing component that limits the position of the capillary column before the connector body and the locking sleeve are connected. The locking sleeve has a second through hole that connects the storage groove and the fastening groove and allows the capillary column to pass through, and the diameter of the second through hole is the same as that of the first through hole; The flexible graphite pressure ring is sleeved on the capillary column and placed in the storage groove, and the connector body has a groove that matches the shape of the flexible graphite pressure ring. An installation handle is welded onto the locking sleeve.

[0006] Furthermore, the pressure ring gasket that contacts the inner wall of the storage tank is sleeved on the capillary column and located on the right side of the flexible graphite pressure ring. The pressure ring gasket is made of stainless steel.

[0007] Furthermore, the fixing component includes a silicone gasket and a fixing cap. A silicone gasket that contacts the inner wall of the fastening groove is fitted onto the capillary column; The fixing cap is provided with external threads, the inner wall of the fastening groove is provided with internal threads, and the fixing cap is provided with a third through hole that allows the capillary column to pass through.

[0008] Furthermore, both the locking sleeve and the fixing cap are provided with lateral slots that allow the capillary column to pass through.

[0009] Furthermore, the mounting handle is provided with anti-slip texture.

[0010] Furthermore, the flexible graphite retaining ring is made of a modified polyimide / graphite composite material.

[0011] Furthermore, the internal thread in the storage groove and the external thread on the connector body are both multi-start rectangular threads with a thread lead of 8-12mm, and the internal thread in the fastening groove and the external thread on the fixing cap are both multi-start rectangular threads with a thread lead of 6-10mm.

[0012] Furthermore, the width of the lateral slot of the locking sleeve is 1.1-1.3 times the outer diameter of the capillary column, and the slot depth penetrates the radial section of the locking sleeve. The width of the lateral slot of the fixing cap is the same as the width of the lateral slot of the locking sleeve, and the slot depth penetrates the radial section of the fixing cap. The edge of the lateral slot wall is rounded.

[0013] Compared with the prior art, the beneficial effects of this utility model are: 1. Improved operating efficiency: The use of a 2-head multi-thread allows the locking sleeve to be locked / separated from the connector body in just 1-2 turns. Combined with the lateral separation design with side slots, the disassembly and assembly time for a single chromatographic column is ≤2 minutes, which is significantly more efficient than traditional devices. In addition, the installation handle has anti-slip texture, and no tools are required throughout the process, reducing the operating threshold. 2. Stable sealing performance: The flexible graphite pressure ring is made of modified polyimide / graphite composite material, which has both high temperature resistance and high resilience. Combined with the size compensation function of the stainless steel pressure ring gasket, there is still no air leakage after 10 consecutive replacements. The sealing reliability is far superior to that of traditional fragile graphite pressure rings. 3. Column protection: The rounded corners of the side grooves prevent scratching the outer wall of the column during separation and eliminate the need for axial extraction of the column, thus extending the column's lifespan. 4. Cost reduction: Flexible graphite pressure rings can be reused more than 50 times, which greatly reduces the replacement cost of vulnerable parts compared to traditional single-use graphite washers. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 for Figure 1 Enlarged view of section A (labeled A); Figure label: 1. Connector body; 11. Groove; 2. First through hole; 3. Capillary column; 4. Locking sleeve; 41. Storage groove; 42. Fastening groove; 43. Second through hole; 5. Flexible graphite pressure ring; 6. Pressure ring gasket; 7. Silicone gasket; 8. Fixing cap; 9. Installation handle. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model. The present utility model will be further described with reference to the accompanying drawings and embodiments: like Figure 1 and Figure 2As shown, a rapid sealing column connection device for a gas chromatograph includes a connector body 1, a locking sleeve 4, a flexible graphite pressure ring 5, a pressure ring gasket 6, a silicone gasket 7, a fixing cap 8, and an installation handle 9. One end of the connector body 1 is fixedly connected to the gas chromatograph's injection port (or detector) using a nut connection method in the prior art. This part does not involve any innovative improvement of this utility model and is not shown in the figure, so it will not be described in detail. The specific process is simply described as follows: Through a column connector nut that can connect to the injection port body and a sealing gasket, the sealing gasket and the connector body of this patent are placed inside the connector nut, so that the bottom of the liner of the injection port is connected to the body in the device, forming a seal without dead volume and without leakage.

[0016] A first through hole 2 is provided along the axial direction inside the connector body 1. The nominal diameter of the first through hole 2 is adapted to the outer diameter of the capillary column 3 (adapted to common capillary column specifications: φ0.25mm, φ0.32mm, φ0.53mm), with a dimensional tolerance of H7. It is used to guide the capillary column 3 to be accurately inserted into the injection port / detector end, avoiding column displacement caused by pore size deviation. The outer wall of the connector body 1 is machined with an external thread that matches the internal thread of the storage groove 41, and a groove 11 that matches the shape of the flexible graphite pressure ring 5 is opened at one end near the locking sleeve 4. The inner diameter of the groove 11 is the same as the outer diameter of the flexible graphite pressure ring 5, which is used to position the graphite pressure ring and ensure the sealing fit, and prevent the pressure ring from shifting when axially compressed.

[0017] The locking sleeve 4 is recessed inward at one end near the connector body 1 to form a storage groove 41. The inner wall of the storage groove 41 is machined with an internal thread that matches the external thread of the connector body 1. The end of the locking sleeve 4 away from the connector body 1 is recessed inward to form a fastening groove 42, and the inner wall of the fastening groove 42 is also machined with internal threads. A second through hole 43 is provided along the axial direction inside the locking sleeve 4, connecting the storage groove 41 and the fastening groove 42. The diameter of the second through hole 43 is exactly the same as that of the first through hole 2 (dimensional tolerance H7, coaxiality tolerance ≤0.01mm), ensuring that the capillary column 3 passes through without offset and avoiding the sealing effect due to coaxiality deviation. The locking sleeve 4 has a lateral groove (through along the axial direction) on its side wall, and the fixing cap 8 also has a lateral groove (through along the axial direction) on its side wall. The width of the groove is 1.1 to 1.3 times the outer diameter of the capillary column 3, and the groove depth penetrates the radial section of the locking sleeve 4 / fixing cap 8. The edges of the groove walls are rounded to avoid scratching the outer wall of the capillary column. The outer wall of the locking sleeve 4 is welded with mounting handles 9 (two symmetrically arranged, made of 304 stainless steel). The surface of the handles is machined with diamond-shaped anti-slip texture, which makes it easy to twist and turn by hand without the need for additional tools.

[0018] The flexible graphite pressure ring 5 is made of modified polyimide / graphite composite material. The pressure ring has a cylindrical structure (the inner diameter is the same as the outer diameter of the capillary column 3, and the fitting gap is 0~0.01mm). It can withstand high temperatures up to 350℃. Under axial pressure of 5~10N, it can generate 0.5~1mm axial compression and 0.1~0.2mm radial expansion. It has both the mechanical strength of polyimide and the resilience of graphite. The flexible graphite pressure ring 5 is sleeved on the capillary column 3 and placed in the storage groove 41. One end of it is embedded in the groove 11 of the connector body 1, and the other end is attached to the pressure ring gasket 6. The pressure ring gasket 6 is made of 304 stainless steel (the inner diameter of the pressure ring gasket is consistent with the outer diameter of the capillary column 3, and the fitting clearance is 0~0.01mm). It is sleeved on the capillary column 3 and contacts the inner wall of the storage groove 41. It is used to compensate for the dimensional deviation (machining error, assembly clearance) of the flexible graphite pressure ring 5, avoid the sealing surface gap caused by unreasonable pressure ring size, and ensure that the axial pressure is evenly transmitted to the graphite pressure ring 5. A fixing component, including a silicone gasket 7 and a fixing cap 8, is provided inside the fastening groove 42. The silicone pad 7 is made of fluorosilicone (the outer diameter is the same as the inner diameter of the fastening groove 42; the inner diameter is the same as the outer diameter of the capillary column 3), and is fitted on the capillary column 3 and fits against the inner wall of the fastening groove 42. It is elastic and can slightly clamp the capillary column 3 to pre-define its axial position. The outer wall of the fixing cap 8 is machined with an external thread that matches the internal thread of the fastening groove 42. The fixing cap 8 is a cylindrical structure (the inner wall of the fixing cap 8 is machined with a third through hole (not shown in the figure), the diameter of the third through hole is consistent with the outer diameter of the capillary column 3). After the fixing cap 8 is screwed into the fastening groove 42, it presses the silicone gasket 7 to further fix the capillary column 3 and prevent the chromatographic column from shifting during the installation process.

[0019] Installation process of this utility model 1. Pre-installation: According to the specifications of the capillary column 3 to be installed, select the matching flexible graphite pressure ring 5, pressure ring gasket 6, and silicone gasket 7; put the fixing cap 8 and silicone gasket 7 on the capillary column 3 in sequence, and then put the locking sleeve 4, pressure ring gasket 6, and flexible graphite pressure ring 5 on the capillary column 3. 2. Positioning: Insert the front end of the capillary column 3 into the first through hole 2 of the connector body 1, and adjust the insertion depth to the preset value (the preset depth is determined according to the gas chromatograph model, with the end face of the connector body 1 near the locking sleeve 4 as the reference); tighten the fixing cap 8 (about 1~2 turns), and clamp the capillary column 3 with the silicone gasket 7 to complete the pre-positioning; 3. Sealing connection: Push the locking sleeve 4 to make the internal thread of the storage groove 41 engage with the external thread of the connector body 1. Hold the installation handle 9 and tighten the locking sleeve 4 clockwise. Because of the multi-start thread structure (the external thread of the connector body 1 is a 2-start rectangular thread with a lead of 10mm; the internal thread of the storage groove 41 matches), only 1 to 2 turns are needed to make the end face of the locking sleeve 4 fit against the pressure ring gasket 6. Continue to tighten until you feel slight resistance. The flexible graphite pressure ring 5 is axially compressed by 0.5 to 1mm and radially expanded by 0.1 to 0.2mm, tightly fitting the inner wall of the groove 11 of the connector body 1 and the outer wall of the capillary column 3, forming a two-way seal. 4. Removal of the fixing cap: After the connector body 1 and the locking sleeve 4 are sealed and installed, loosen the fixing cap 8 in the opposite direction (loosen 1~2 turns to disengage from the internal thread of the fastening groove 42). Since the side wall of the fixing cap 8 has a lateral groove, it is not necessary to completely remove the fixing cap 8 from the end of the capillary column 3. Simply move the fixing cap 8 laterally along the groove direction to quickly separate the fixing cap 8 from the capillary column 3, saving disassembly time.

[0020] Capillary column replacement and graphite ring replacement procedures Column separation: When it is necessary to replace the capillary column 3, first hold the installation handle 9 and loosen the locking sleeve 4 counterclockwise (due to the multi-thread structure, only 1-2 turns are needed) to completely separate the locking sleeve 4 from the connector body 1; at this time, because the side wall of the locking sleeve 4 has a lateral groove, it is not necessary to pull the locking sleeve 4 out from the end of the capillary column 3. Simply move the capillary column 3 laterally along the groove direction to achieve rapid separation of the locking sleeve 4 and the capillary column 3, avoiding end face damage caused by axial extraction of the chromatographic column; Graphite retainer ring replacement: If the flexible graphite retainer ring 5 needs to be replaced (e.g., if it has been used more than 50 times or is deformed), after the locking sleeve 4 is separated from the capillary column 3, use tweezers to gently push the flexible graphite retainer ring 5 along the axial direction of the second through hole 43 to adjust the position of the retainer ring so that it is completely free from the constraint range of the storage groove 41; then pull the old retainer ring out from the end along the axial direction of the capillary column 3; take a new flexible graphite retainer ring 5 (of the same specification), first apply a layer of graphite grease to the inner wall of the retainer ring (to facilitate insertion), then insert it into the capillary column 3 and push it to the corresponding position in the storage groove 41 (with one end of the retainer ring fitting against the bottom surface of the groove 11 of the connector body 1), and the retainer ring replacement can be completed without tools; after replacement, the installation process must be repeated to ensure reliable sealing.

[0021] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The descriptions of the above embodiments and specifications are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by this utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A rapid-sealing column connection device for a gas chromatograph, comprising an injection port and a detector respectively connected to both ends of a capillary column (3), characterized in that, It also includes a connector body (1) that is connected at one end to the injection port or detector. The connector body (1) has a first through hole (2) that allows the capillary column (3) to pass through; The locking sleeve (4) has a storage groove (41) at one end near the connector body (1) and a fastening groove (42) at the other end away from the connector body (1). The storage groove (41) has an internal thread, and the connector body (1) has an external thread that mates with the internal thread. The fastening groove (42) has a fixing component that limits the position of the capillary column (3) before the connector body (1) and the locking sleeve (4) are connected. The locking sleeve (4) has a second through hole (43) that connects the storage groove (41) and the fastening groove (42) and allows the capillary column (3) to pass through, and the diameter of the second through hole (43) is the same as that of the first through hole (2); The flexible graphite pressure ring (5) is sleeved on the capillary column (3) and is located in the storage groove (41), and the connector body (1) is provided with a groove (11) that matches the shape of the flexible graphite pressure ring (5). An installation handle (9) is welded onto the locking sleeve (4).

2. The rapid sealing column connection device for a gas chromatograph according to claim 1, characterized in that, The pressure ring gasket (6) that is in contact with the inner wall of the storage tank (41) is sleeved on the capillary column (3) and is located on the right side of the flexible graphite pressure ring (5). The pressure ring gasket (6) is made of stainless steel.

3. The rapid sealing column connection device for a gas chromatograph according to claim 1, characterized in that, The fixing component includes a silicone gasket (7) and a fixing cap (8). A silicone gasket (7) in contact with the inner wall of the fastening groove (42) is fitted onto the capillary column (3); The fixing cap (8) is provided with external threads, the inner wall of the fastening groove (42) is provided with internal threads, and the fixing cap (8) is provided with a third through hole that allows the capillary column (3) to pass through.

4. The rapid sealing column connection device for a gas chromatograph according to claim 3, characterized in that, Both the locking sleeve (4) and the fixing cap (8) have lateral slots that allow the capillary column (3) to pass through.

5. A rapid sealing column connection device for a gas chromatograph according to claim 1, characterized in that, The mounting handle (9) is provided with anti-slip texture.

6. A rapid sealing column connection device for a gas chromatograph according to claim 1, characterized in that, The flexible graphite pressure ring (5) is made of modified polyimide / graphite composite material.

7. A rapid sealing column connection device for a gas chromatograph according to claim 3, characterized in that, The internal thread in the storage groove (41) and the external thread on the connector body (1) are both multi-start rectangular threads with a thread lead of 8-12mm. The internal thread in the fastening groove (42) and the external thread on the fixing cap (8) are both multi-start rectangular threads with a thread lead of 6-10mm.

8. A rapid sealing column connection device for a gas chromatograph according to claim 3, characterized in that, The width of the lateral slot of the locking sleeve (4) is 1.1-1.3 times the outer diameter of the capillary column (3), and the slot depth penetrates the radial section of the locking sleeve (4). The width of the lateral slot of the fixing cap (8) is the same as the width of the lateral slot of the locking sleeve (4), and the slot depth penetrates the radial section of the fixing cap (8). The edge of the lateral slot is rounded.

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