A gas chromatograph

Abstract

The present invention relates to the technical field of chromatographs, and specifically to a gas chromatograph, comprising a detection box, a sampling assembly for sample sampling is arranged on the top of the detection box, an air intake assembly is arranged in the detection box, and the top of the air intake assembly extends to the top of the detection box; the sampling assembly comprises a sample extraction cylinder for sample gas absorption; a sample plug interface is provided on the top of the sample extraction cylinder, a connecting cylinder is coaxially arranged on the inner wall of the sample extraction cylinder and the plug interface, a sliding sealing sheet is slidably arranged on the inner wall of the plug interface, a connecting needle is arranged through the middle of the sliding sealing sheet, and a sealing film is arranged on the needle tip of the connecting needle. The arrangement of the sampling assembly can quantitatively suck out the sample in the sample plastic bottle and inject it into the air intake assembly. In this process, the sample plastic bottle only needs to be inserted into a preset position, and there will be no leakage or other gas infiltration into the sample plastic bottle during the insertion process, thereby ensuring the purity and safety of the sample after sampling.

Description

Technical Field

[0001] The invention relates to the technical field of chromatographs, in particular to a gas chromatograph. Background Art

[0002] The working principle of gas chromatograph is based on chromatographic separation technology and detection technology. When the sample is "injected" into the injector by a micro-syringe, it is carried by the carrier gas into the packed column or capillary chromatographic column. Due to the difference in the distribution or adsorption coefficient between the mobile phases of the components in the sample in the chromatographic column, under the flushing of the carrier gas, the components are repeatedly distributed between the two phases so that the components are separated in the column. Subsequently, the detector connected to the column detects the components in order according to their physical and chemical properties.

[0003] The patent with application publication number CN117120837A discloses a gas chromatograph body, whose internal space is thermally blocked from the outside, and an insulating component is interposed between the gas chromatograph body and each cooling fan in the at least one cooling fan, so that each cooling fan in the at least one cooling fan is thermally isolated relative to the gas chromatograph body.

[0004] The above patent first needs to suck the gas out of the sample plastic bottle through a syringe or other equipment before conducting gas detection, and then inject the sucked sample into the gas chromatograph for detection through the syringe. First, in the process of sucking the sample, there may be a phenomenon that the gas in the needle tube is not emptied, which may affect the detection result. After sucking the gas, the needle tube needs to be transferred, and the needle tube may fall during this process. Then the sucked gas is injected into the gas chromatograph. The operation process is relatively cumbersome, and the staff transports the gas back and forth. Improper operation may affect the accuracy of the test results. Summary of the invention

[0005] In response to the problems in the prior art, the present invention provides a gas chromatograph that can realize the injection of sample gas. During the injection process, the gas will not come into contact with the outside gas and the staff does not need to draw it through a syringe, thereby avoiding the possibility of the sample gas being affected by the outside world during the injection process. During the injection of the sample gas, there will be no leakage or other gases will not penetrate into the sample plastic bottle, thereby ensuring the purity and safety of the sample after sampling.

[0006] The technical solution adopted by the present invention to solve its technical problems is: a gas chromatograph, including a detection box, a sampling assembly for sample sampling is arranged on the top of the detection box, an air intake assembly is arranged in the detection box, and the top of the air intake assembly extends to the top of the detection box; the sampling assembly includes a sample extraction cylinder for sample gas absorption; a sample plug interface is opened on the top of the sample extraction cylinder, a connecting cylinder is coaxially arranged on the inner wall of the sample extraction cylinder and the plug interface, a sliding sealing sheet is slidably arranged on the inner wall of the plug interface, a connecting needle is arranged through the middle of the sliding sealing sheet, and a sealing film is arranged on the tip of the connecting needle.

[0007] Specifically, the sealing film is a polyethylene film, and the thickness of the sealing film is within 1mm to 5mm. The middle part of the sliding sealing sheet is made of a hard material, and a sealing ring is provided along the circumferential direction of the outer wall of the edge contacting the plug interface.

[0008] Specifically, the sliding sealing sheet is fixedly connected to a push rod on one side close to the connecting tube, a reset spring is sleeved on the outer wall of the portion between the push rod and the bottom of the connecting tube, an injection port is opened at the bottom of the connecting tube, and a sealing plug is fixedly connected to one end of the push rod extending to the outside of the connecting tube, and the sealing plug is arranged in cooperation with the injection port.

[0009] Specifically, a rubber stopper is slidably arranged in the sample extraction tube, and the rubber stopper and the inner cavity of the sample extraction tube form a negative pressure chamber area. A first air hole is opened on the top of the sample extraction tube, and the first air hole is connected to the negative pressure chamber area; the air hole is connected to the air intake assembly through the injection tube, and a one-way valve is connected to the injection tube at one end close to the sample extraction tube.

[0010] Specifically, the outer wall of the sample extraction tube is fixedly connected to a driving member, the output end of the driving member is fixedly connected to a gear, the outer wall of the sample extraction tube is slidably provided with a rack, the end of the rack close to the inner cavity port of the sample extraction tube is connected to the rubber stopper through a pull rod, and the gear is meshed with the rack.

[0011] Specifically, the air intake assembly includes an air intake chamber, an air intake port is opened on one side of the air intake chamber, a nitrogen bottle is placed on one side of the air intake chamber, the nitrogen bottle is connected to the air intake port through a hose, and a pressure regulating valve for controlling the nitrogen flow rate is installed in the middle of the hose.

[0012] Specifically, an injection cap is provided on the top of the air inlet chamber, a connecting hole is opened in the middle of the top of the injection cap, and an injection pad is fixedly connected to the middle of the injection cap. The edge of the injection pad is tightly set by a pressing elastic pad, and the end of the injection tube away from the sample extraction cylinder passes through the injection pad.

[0013] Specifically, a liner is provided in the middle of the air inlet chamber, a shunt tube is provided through the bottom of the liner, a temperature control box is installed inside the detection box, a capillary chromatographic column is installed in the temperature control box, the capillary chromatographic column is provided through the bottom of the shunt tube, and a detector is provided at one end of the capillary chromatographic column away from the shunt tube.

[0014] Specifically, a plurality of circles of heat exchange tubes are arranged around the outer wall of the temperature control box, and the heat exchange tubes are connected in sequence. A liquid inlet is arranged at one end of the top of the heat exchange tube, and a liquid outlet is arranged at one end of the bottom of the heat exchange tube.

[0015] Beneficial effects of the present invention: Compared with the prior art, the gas chromatograph described in the present invention can quantitatively suck out the sample in the sample plastic bottle and inject it into the air inlet component through the setting of the sampling component. In this process, it is only necessary to insert the sample plastic bottle to a preset position, and there will be no leakage or other gas infiltration into the sample plastic bottle during the insertion process, thereby ensuring the purity and safety of the sample after sampling. At the same time, the sampling amount can be controlled according to needs during sampling. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 This is a schematic diagram of the internal structure of the detection box of the present invention;

[0019] Figure 3 This is a schematic diagram of the three-dimensional structure of the sampling assembly of the present invention;

[0020] Figure 4 It is a schematic diagram of the three-dimensional structure of the capillary chromatographic column of the present invention;

[0021] Figure 5 is a cross-sectional view of the sample extraction tube of the present invention;

[0022] Figure 6 For the present invention Figure 5 Enlarged view of point A in the middle;

[0023] Figure 7 is a cross-sectional view of the air inlet chamber of the present invention;

[0024] Figure 8 For the present invention Figure 7 Schematic diagram of the structure at point B in the middle.

[0025] In the figure: 1, detection box; 2, sampling assembly; 21, sample extraction tube; 211, pull rod; 212, rubber plug; 213, connecting tube; 214, sliding sealing sheet; 215, return spring; 216, ejector rod; 217, sealing plug; 218, injection port; 219, connecting needle; 210, sealing film;

[0026] 22. gear; 23. rack; 24. negative pressure chamber area; 29. ​​injection tube; 291. one-way valve; 3. air inlet assembly; 31. air inlet chamber; 311. liner; 32. shunt tube; 33. injection cap; 331. air inlet; 332. injection pad; 333. tight elastic pad;

[0027] 4. Nitrogen bottle; 41. Pressure regulating valve; 5. Sample plastic bottle; 6. Temperature control box; 61. Heat exchange tube; 62. Liquid inlet; 63. Liquid outlet; 66. Capillary chromatographic column. DETAILED DESCRIPTION

[0028] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0029] like Figure 1-Figure 8 As shown, a gas chromatograph of the present invention comprises a detection box 1, a sampling assembly 2 for sample sampling is arranged on the top of the detection box 1, an air intake assembly 3 is arranged inside the detection box 1, and the top of the air intake assembly 3 extends to the top of the detection box 1; the sampling assembly 2 comprises a sample extraction tube 21 for sample gas absorption; a sample plug interface is provided on the top of the sample extraction tube 21, a connecting tube 213 is coaxially arranged on the inner wall of the sample extraction tube 21 and the plug interface, a sliding sealing sheet 214 is slidably arranged on the inner wall of the plug interface, a connecting needle 219 is penetrated through the middle of the sliding sealing sheet 214, and a sealing film 210 is arranged on the needle tip of the connecting needle 219.

[0030] Generally speaking, the sampling volume of gas samples is usually between several milliliters and tens of milliliters. This range can meet the needs of most gas chromatography analyses and will not cause excessive burden on the instrument. Through the setting of the sampling component 2, the sample in the sample plastic bottle 5 can be quantitatively sucked out and injected into the air intake component 3. In this process, it is only necessary to insert the sample plastic bottle 5 into the preset position, and there will be no leakage or other gases infiltrating into the sample plastic bottle 5 during the insertion process, thereby ensuring the purity of the sample after sampling. At the same time, the sampling amount can be controlled according to needs during sampling. In the prior art, if the sampling amount is small through the syringe, the sample needs to be re-absorbed and transferred and then injected, which increases the workload of the staff. The present application can timely inject gas according to the preset air intake volume through the sampling component 2. Even if multiple gas injections are required, the intervals between them are short and rapid, thereby ensuring the accuracy of the test results.

[0031] Specifically, the sealing film 210 is a polyethylene film, and the thickness of the sealing film 210 is within 1 mm to 5 mm. The middle part of the sliding sealing sheet 214 is made of a hard material, and a sealing ring is provided along the circumferential direction of the outer wall of the edge contacting the plug interface.

[0032] The polyethylene film is lightweight and waterproof and moisture-proof. The polyethylene film has a certain degree of ductility. When it is subjected to negative pressure on one side, it will deform first. However, when the negative pressure reaches a certain value, the sealing film 210 will rupture. The thickness of the sealing film 210 is between 1mm and 5mm. When negative pressure is generated, the sealing film 210 placed on the top of the connecting needle 219 can be compressed by the negative pressure. The sealing film 210 allows the sample gas to flow into the sample extraction tube 21. Before use, the sealing film 210 seals the connecting needle 219 to prevent external gas from entering and causing changes in the purity of the sample gas, which affects the detection results.

[0033] Specifically, the sliding sealing sheet 214 is fixedly connected to a push rod 216 on one side close to the connecting tube 213, a return spring 215 is sleeved on the outer wall of the portion between the push rod 216 and the bottom of the connecting tube 213, an injection port 218 is provided at the bottom of the connecting tube 213, and a sealing plug 217 is fixedly connected to one end of the push rod 216 extending to the outside of the connecting tube 213, and the sealing plug 217 is arranged in cooperation with the injection port 218.

[0034] A rubber stopper 212 is slidably arranged in the sample extraction tube 21, and the rubber stopper 212 and the inner cavity of the sample extraction tube 21 form a negative pressure chamber area 24. A first air hole is opened at the top of the sample extraction tube 21, and the first air hole is connected to the negative pressure chamber area 24; the air hole is connected to the air intake component 3 through the injection tube 29, and the injection tube 29 is connected to a one-way valve 291 at one end close to the sample extraction tube 21.

[0035] When the sample plastic bottle 5 is inserted into the plug interface, the mouth of the sample plastic bottle 5 first contacts the connecting needle 219 during the process of entering the plug interface, and the connecting needle 219 will be inserted into the sample plastic bottle 5. When the sample plastic bottle 5 continues to be pushed downward, the sample plastic bottle 5 will fit with the sliding sealing sheet 214 and push the sliding sealing sheet 214 to move closer to the sample extraction tube 21. At this time, the sliding sealing sheet 214 pushes the push rod 216 to move toward the negative pressure area 24. During this process, the reset spring 215 will be compressed. When the sample plastic bottle 5 is pushed into place, the sample plastic bottle 5 is released. Under the push of the reset spring 215, the sample plastic bottle 5 and the sliding sealing sheet 214 will move upward. At this time, the sealing plug 217 re-enters the injection port 218 to seal the injection port 218.

[0036] By pulling the rubber stopper 212, negative pressure is generated in the negative pressure chamber area 24. At this time, the sealing plug 217 will move into the negative pressure chamber area 24, and the injection port 218 will be opened. During this process, the reset spring 215 will be compressed, and the sample gas placed in the connecting tube 213 will enter the pressure chamber area 24 through the injection port 218 set at the bottom; when the rubber stopper 212 is continuously pulled, the sealing plug 217 is in a continuously open state, which is conducive to the entry of sample gas. When the rubber stopper 212 stops being pulled, the sealing plug 217 seals the injection port 218 again under the push of the reset spring 215.

[0037] In the process of pushing the rubber stopper 212 to move toward the connecting tube 213, the sealing plug 217 and the injection port 218 are in a sealed state, and the gas enters the injection tube 29 through the air hole and enters the air intake assembly 3. The one-way valve 291 can prevent the gas from flowing back and avoid contaminating the gas in the sample plastic bottle 5.

[0038] Specifically, the outer wall of the sample extraction tube 21 is fixedly connected to a driving member, and the output end of the driving member is fixedly connected to a gear 22. A rack 23 is slidably provided on the outer wall of the sample extraction tube 21. The end of the rack 23 close to the inner cavity port of the sample extraction tube 21 is connected to the rubber stopper 212 through a pull rod 211, and the gear 22 is meshed with the rack 23.

[0039] During the sample absorption process, the gear 22 can be driven to rotate by controlling the driving member. The gear 22 drives the rack 23 to move during the rotation. The rack 23 can drive the rubber plug 212 to move through the pull rod 211 when moving, thereby driving the rubber plug 212 to move. The staff can also pull and push the rack 23 to move, so as to realize the injection of sample gas.

[0040] Specifically, the air intake assembly 3 includes an air intake chamber 31, an air intake port 331 is opened on one side of the air intake chamber 31, a nitrogen bottle 4 is placed on one side of the air intake chamber 31, the nitrogen bottle 4 is connected to the air intake port 331 through a hose, and a pressure regulating valve 41 for controlling the nitrogen flow rate is installed in the middle of the hose.

[0041] After the sample gas enters the air inlet chamber 31, the nitrogen in the nitrogen bottle 4 continues to enter the air inlet chamber 31 through the air inlet 331, driving the sample gas to the direction of the capillary chromatographic column 66. The setting of the pressure-stabilizing valve 41 allows the nitrogen to enter the air inlet chamber 31 at a stable pressure. The stability of the nitrogen flow rate not only affects the separation effect, but also directly affects the accuracy and reliability of the analysis. If the nitrogen entry speed is unstable, it will cause the signal received by the detector to fluctuate greatly, thereby affecting the accuracy of the quantitative analysis.

[0042] Specifically, a sampling cap 33 is provided on the top of the air inlet chamber 31, a connecting hole is opened in the middle of the top of the sampling cap 33, and an injection pad 332 is fixedly connected to the middle of the sampling cap 33, the edge position of the injection pad 332 is tightly set by a pressing elastic pad 333, and the end of the sampling tube 29 away from the sample extraction cylinder 21 passes through the injection pad 332.

[0043] The edge of the injection pad 332 can be compressed by pressing against the elastic pad 333 to ensure the sealing of the air inlet chamber 31 . One end of the injection tube 29 passes through the injection pad 332 , so that the sample gas can enter the air inlet chamber 31 .

[0044] Specifically, a liner tube 311 is provided in the middle of the air inlet chamber 31, and a shunt tube 32 is provided through the bottom of the liner tube 311. A temperature control box 6 is installed inside the detection box 1, and a capillary column 66 is installed in the temperature control box 6. The capillary column 66 is provided through the bottom of the shunt tube 32, and a detector is provided at one end of the capillary column 66 away from the shunt tube 32; a plurality of circles of heat exchange tubes 61 are provided around the outer wall of the temperature control box 6, and the heat exchange tubes 61 are connected in sequence, a liquid inlet 62 is provided at the top end of the heat exchange tube 61, and a liquid outlet 63 is provided at the bottom end of the heat exchange tube 61.

[0045] The sample gas enters the capillary column 66 through the shunt tube 32, wherein before detection, liquid of preset temperature is continuously injected into the heat exchange tube 61 through the liquid inlet 62, so that the temperature control box 6 reaches the preset range, ensuring that the capillary column 66 is in a constant state. By placing the capillary column 66 in the temperature control box 6, the influence of external temperature is reduced, and the accuracy of the detection result is ensured. The gas passing through the capillary column 66 enters the detector for detection.

[0046] Working principle: First, when the sample plastic bottle 5 is inserted into the plug interface, the mouth of the sample plastic bottle 5 will first contact the connecting needle 219 during the process of entering the plug interface, and the connecting needle 219 will be inserted into the sample plastic bottle 5. When the sample plastic bottle 5 continues to be pushed downward, the sample plastic bottle 5 will fit with the sliding sealing sheet 214 and push the sliding sealing sheet 214 to move closer to the sample extraction tube 21. At this time, the sliding sealing sheet 214 pushes the push rod 216 to move toward the negative pressure area 24. During this process, the reset spring 215 will be compressed. When the sample plastic bottle 5 is pushed into place, the sample plastic bottle 5 is released. Under the push of the reset spring 215, the sample plastic bottle 5 and the sliding sealing sheet 214 will move upward. At this time, the sealing plug 217 re-enters the injection port 218 to seal the injection port 218.

[0047] By pulling the rubber stopper 212, negative pressure is generated in the negative pressure chamber area 24. At this time, the sealing plug 217 will move into the negative pressure chamber area 24, and the injection port 218 will be opened. During this process, the reset spring 215 will be compressed, and the sample gas placed in the connecting tube 213 will enter the pressure chamber area 24 through the injection port 218 set at the bottom; when the rubber stopper 212 is continuously pulled, the sealing plug 217 is in a continuously open state, which is conducive to the entry of sample gas. When the rubber stopper 212 stops being pulled, the sealing plug 217 seals the injection port 218 again under the push of the reset spring 215.

[0048] In the process of pushing the rubber stopper 212 to move toward the connecting tube 213 , the sealing stopper 217 and the injection port 218 are in a sealed state, and the gas enters the injection tube 29 through the air hole and then enters the gas inlet assembly 3 .

[0049] After the sample gas enters the air inlet chamber 31, the nitrogen in the nitrogen bottle 4 continuously enters the air inlet chamber 31 through the air inlet 331, driving the sample gas to the direction of the capillary chromatographic column 66. The setting of the pressure-stabilizing valve 41 allows the nitrogen to enter the air inlet chamber 31 at a stable pressure. The sample gas enters the capillary chromatographic column 66 through the diversion tube 32. Before detection, liquid at a preset temperature is continuously injected into the heat exchange tube 61 through the liquid inlet 62, so that the temperature control box 6 reaches a preset range, ensuring that the capillary chromatographic column 66 is in a constant state. By placing the capillary chromatographic column 66 in the temperature control box 6, the gas passing through the capillary chromatographic column 66 enters the detector for detection.

[0050] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A gas chromatograph, characterized in that: It comprises a detection box (1), wherein a sampling assembly (2) for sampling a sample is arranged on the top of the detection box (1), an air intake assembly (3) is arranged inside the detection box (1), and the top of the air intake assembly (3) extends to the top of the detection box (1); The sampling assembly (2) comprises a sample extraction tube (21) for absorbing sample gas; a sample plugging port is provided at the top of the sample extraction tube (21); a connecting tube (213) is coaxially arranged on the inner wall of the sample extraction tube (21) and the plugging port; a sliding sealing sheet (214) is slidably arranged on the inner wall of the plugging port; a connecting needle (219) is provided through the middle of the sliding sealing sheet (214); and a sealing film (210) is provided at the tip of the connecting needle (219); A push rod (216) is fixedly connected to one side of the sliding sealing sheet (214) close to the connecting tube (213); a return spring (215) is sleeved on the outer wall of the portion between the push rod (216) and the bottom of the connecting tube (213); a sample inlet (218) is provided at the bottom of the connecting tube (213); a sealing plug (217) is fixedly connected to one end of the push rod (216) extending to the outside of the connecting tube (213); and the sealing plug (217) is arranged in coordination with the sample inlet (218); A rubber stopper (212) is slidably disposed in the sample extraction tube (21), and the rubber stopper (212) and the inner cavity of the sample extraction tube (21) form a negative pressure cavity area. A first air hole is opened at the top of the sample extraction tube (21), and the first air hole is connected to the negative pressure cavity area; the air hole is connected to the air intake assembly (3) through a sample injection tube (29), and a one-way valve (291) is connected to one end of the sample injection tube (29) close to the sample extraction tube (21).

2. A gas chromatograph according to claim 1, characterized in that: The sealing film (210) is a polyethylene film, and the thickness of the sealing film (210) is within the range of 1 mm to 5 mm. The middle portion of the sliding sealing sheet (214) is made of a hard material, and a sealing ring is provided along the circumferential direction of the outer wall of the edge where the plug interface contacts.

3. A gas chromatograph according to claim 2, characterized in that: The outer wall of the sample extraction tube (21) is fixedly connected to a driving member, and the output end of the driving member is fixedly connected to a gear (22). A rack (23) is slidably provided on the outer wall of the sample extraction tube (2). One end of the rack (23) close to the inner cavity port of the sample extraction tube (21) is connected to a rubber stopper (212) via a pull rod (211), and the gear (22) is meshed with the rack (23).

4. A gas chromatograph according to claim 3, characterized in that: The air intake assembly (3) comprises an air intake chamber (31), an air intake port (331) being provided on one side of the air intake chamber (31), a nitrogen bottle (4) being placed on one side of the air intake chamber (31), the nitrogen bottle (4) being connected to the air intake port (331) via a hose, and a pressure regulating valve (41) for controlling the nitrogen flow rate being installed in the middle of the hose.

5. A gas chromatograph according to claim 4, characterized in that: A sampling cap (33) is arranged at the top of the air inlet chamber (31), a connecting hole is opened in the middle of the top of the sampling cap (33), and an injection pad (332) is fixedly connected to the middle of the sampling cap (33), the edge of the injection pad (332) is tightly arranged by abutting against an elastic pad (333), and one end of the sampling tube (29) away from the sample extraction cylinder (21) passes through the injection pad (332).

6. A gas chromatograph according to claim 5, characterized in that: A liner tube (311) is arranged in the middle of the air inlet chamber (31), a shunt tube (32) is arranged through the bottom of the liner tube (311), a temperature control box (6) is installed inside the detection box (1), a capillary chromatographic column (66) is installed inside the temperature control box (6), the capillary chromatographic column (66) is arranged through the bottom of the shunt tube (32), and a detector is arranged at one end of the capillary chromatographic column (66) away from the shunt tube (32).

7. A gas chromatograph according to claim 6, characterized in that: The outer wall of the temperature control box (6) is surrounded by a plurality of circles of heat exchange tubes (61), the heat exchange tubes (61) are connected in sequence, a liquid inlet (62) is provided at one end of the top of the heat exchange tube (61), and a liquid outlet (63) is provided at one end of the bottom of the heat exchange tube (61).

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