CN111044650A - Self-headspace gas chromatography sample injector - Google Patents

Abstract

The invention discloses a self-headspace gas chromatography sample injector, which comprises: the device comprises a control system, a gas circuit system, a positioning system and a bottom plate; the control system comprises a control panel and a single chip microcomputer, wherein the control panel is connected with the single chip microcomputer through a flat cable; the positioning system comprises a sample disc, a gear disc, a motor, a cylinder arm, a middle shaft lever and a paraxial shaft lever; the gas path system comprises a three-way needle inlet valve, a three-way needle withdrawing valve, an air pressure stabilizing valve, a two-way air inlet valve, a flow limiting filter, a six-way sample inlet valve, a two-way air outlet valve, a three-way exhaust valve, a vacuum pump and a sample inlet needle. The invention can realize automatic self-headspace sample introduction of a gas sample by combining with gas chromatography.

Description

Self-headspace gas chromatography sample injector

Technical Field

The invention relates to the technical field of gas detection, in particular to a self-headspace gas chromatography sample injector.

Background

Human activities can discharge various gases into the atmosphere, such as air-conditioning refrigerant freon; sulfur dioxide, hydrogen sulfide, carbon dioxide and carbon monoxide generated by steel making and coal burning; nitrous oxide produced by fertilization of cement manufacturing or agricultural soils; methane and the like generated by rice planting or coal mining can pollute the atmospheric environment, and the prevention and control of atmospheric pollution are not slow at all. The sampling, analyzing and monitoring of the discharged polluted gas is a precondition for researching gas pollution and performing targeted prevention and control, but the content concentration of a lot of gases in the atmosphere is very low, and the sample gas needs to be sampled and then sent to a special instrument in a laboratory for analysis. The glass container can be used as a preferred container for loading trace gas samples due to small adsorbability to gas, and is also a preferred container for analysis of an automatic gas sample injector. The gas is easy to compress, easy to diffuse or leak, and greatly influenced by temperature, and is generally injected to a chromatographic sample inlet by using an airtight needle for analysis, and automatic sample injection is also generally carried out by using a mechanical arm to drive the airtight needle for injection, but the structure is complex, and the cost is high.

The headspace sampling is a convenient and fast sample sampling processing mode in gas chromatography, and the principle is that a sample to be detected is placed in a closed container, volatile components are volatilized from a sample matrix through heating, balance is achieved in a gas-liquid (or gas-solid) phase, and top gas is directly extracted for chromatographic analysis, so that the components and the content of the volatile components in the sample are detected. The headspace sampling technology can avoid a tedious and tedious sample pretreatment process, avoid interference of an organic solvent on analysis, and reduce pollution to a chromatographic column and a sampling port.

However, the existing sample injector can not discharge the sample inside the sample injector quickly in time when sampling the object, which not only reduces the working efficiency of the sample injector, but also reduces the activity of the sample object, and the protection measures are not proper, and the traditional headspace sample injection mainly aims at gas-liquid or gas-solid mixed samples and all uses heating technology.

Because each component in the gas sample is in a gaseous state, and the gas is easy to compress and store, more samples can be stored in a small volume, and the sample injection power can be generated by compression without heating. The gas is sensitive to pressure, and quantitative sampling under normal pressure by adopting a sampling valve and a quantitative tube is the most convenient and efficient sampling mode in the field of gas analysis.

Therefore, how to provide a simple and efficient automatic sample feeding technology suitable for a gas sample is a problem that needs to be solved urgently by those skilled in the art.

Disclosure of Invention

In view of the above, the invention provides a self-headspace gas chromatography sample injector, which combines a headspace sample injection technology, a valve sample injection technology and a singlechip automatic control technology, and can realize automatic self-headspace sample injection of a gas sample by adopting a control system, a gas circuit system and a positioning system.

In order to achieve the purpose, the invention adopts the following technical scheme:

a self-headspace gas chromatography sample injector comprises a control system, a gas path system, a positioning system and a bottom plate; the positioning system is electrically connected with the control system; the positioning system is fixed on the bottom plate;

the gas path system comprises a cylinder, a cylinder driving device, a two-way air inlet valve, a flow limiting filter, a six-way sample injection valve, a dosing pipe, a two-way air outlet valve, a three-way exhaust valve, a vacuum pump and an injection device;

the three-way needle inlet valve, the three-way needle withdrawing valve and the air pressure stabilizing valve are communicated through a three-way joint; the three-way needle inlet valve is communicated with an upper air chamber of the air cylinder; the three-way needle withdrawing valve is communicated with a lower air chamber of the air cylinder; the six-way sampling valve is communicated with the flow-limiting filter; the vacuum pump, the three-way exhaust valve, the two-way exhaust valve, the six-way sample injection valve, the flow limiting filter, the two-way intake valve and the injection device are communicated in sequence;

the 1 st interface of the six-way sample valve is connected with high-purity nitrogen, the six-way sample valve is provided with a quantitative pipe, two ends of the quantitative pipe are positioned at the 2 nd interface and the 5 th interface of the six-way sample valve, the 3 rd interface and the 4 th interface of the six-way sample valve are respectively connected with the two-way gas outlet valve and the flow limiting filter, and the 6 th interface of the six-way sample valve is connected with a gas chromatograph;

specifically, the three-way exhaust valve, the three-way needle inlet valve and the three-way needle outlet valve are all normally closed two-position three-way electromagnetic valves, the valve is provided with three interfaces, namely an air inlet, an air outlet and an air outlet, the air outlet is positioned at the top of the valve, the air inlet is sealed by a sealing gasket in a closed state when the valve is not electrified, air cannot pass through the air inlet, and the air outlet is communicated with an air passage of the air outlet; the air inlet is communicated with the air outlet and the air outlet is not communicated when the valve is in the electrified state; the two-way air inlet valve and the two-way air outlet valve are normally closed two-position two-way electromagnetic valves, only have an air inlet and an air outlet, the air inlet is not communicated with the air outlet when the valves are not electrified and closed, and the air inlet is communicated with the air outlet when the valves are electrified and opened.

Further, the air inlet of the two-way air inlet valve is connected with the needle seat, and the air outlet of the two-way air inlet valve is connected with the flow limiting filter; the air outlet of the two-way air outlet valve is connected with the 3 rd interface of the six-way sample injection valve, the air inlet of the two-way air outlet valve is connected with the air outlet of the three-way exhaust valve, the air inlet of the three-way exhaust valve is connected with the vacuum pump, and the air outlet of the three-way exhaust valve is communicated with the atmosphere; the air outlet of the three-way needle inlet valve is connected with the upper air chamber of the square cylinder, the air inlet of the three-way needle inlet valve is connected with the three-way joint, and the air outlet of the three-way needle inlet valve is communicated with the atmosphere; the air outlet of the three-way needle withdrawing valve is connected with the lower air chamber of the square air cylinder, the air inlet of the three-way needle withdrawing valve is connected with the other interface of the three-way joint, and the air outlet is communicated with the atmosphere.

Preferably, the main body of the flow-limiting filter is made of stainless steel, micron-sized stainless steel powder is filled in an internal gas channel, the powder is sintered and fixed at high temperature, the flow-limiting filter can play a role in three aspects, one is capable of filtering more than micron-sized dust particles in a gas sample, and the other is that the filter only occupies microliter dead volume, so that the influence of gas residue or cross contamination of the filter sample can be greatly reduced; thirdly, the gas inlet flow rate of the gas sample can be limited, so that the gas sample in the gas inlet pipeline flows in a slow steady flow state, the gas sample is prevented from being mixed with residual gas in the gas inlet pipeline in a turbulent flow manner, the newly-introduced sample gas is flushed by adopting a slow pushing and replacing mode, the original pipeline old sample gas is flushed, the sample introduction precision is improved, and the flushing time is shortened.

Preferably, the gas circuit connection system provides two self-headspace sampling modes, one is a direct self-headspace sampling mode, the sample gas is stored in a headspace sample bottle in a compressed form, when the direct headspace sampling mode is adopted, the two-way air inlet valve and the two-way air outlet valve are in an open state, the three-way air outlet valve is in a closed state, when the sampling needle is inserted into the headspace sample bottle, the gas sample compressed in the headspace bottle sequentially passes through the needle seat, the flow limiting filter and the 4 th, 5 th, 2 nd and 3 rd interfaces of the six-way sampling valve under the action of self pressure and then is discharged into the atmosphere through the two-way air outlet valve and the air outlet of the three-way air outlet valve, the compressed sample gas washes the air inlet pipeline in a slow-pushing replacement mode when passing through the compressed sample gas, until the pressure of the compressed sample gas is balanced with the atmospheric pressure, and the gas sample to be analyzed is stored in the quantitative pipe of the six-way sampling valve, the redundant sample gas is discharged into the atmosphere to realize the automatic loading of the gas sample, when the sample loading is finished, the six-way sample injection valve is opened, and the sample gas stored in the quantitative tube is brought into the chromatogram by the carrier gas for sample injection analysis; another headspace sampling mode is to use the vacuum pump, the two-way exhaust valve and the three-way exhaust valve as auxiliary components, before sampling, a small amount of gas sample can be used to clean the gas inlet pipeline, so as to improve the cleaning efficiency and the cleaning degree, the main action mode is to open the vacuum pump, the three-way exhaust valve and the two-way exhaust valve first after the sampling needle is inserted into the headspace sample bottle, the vacuum pump will clean the gas inlet pipeline, the flow-limiting filter and the quantitative tube at the rear end of the two-way intake valve, then close the two-way exhaust valve, open the two-way intake valve, let the gas sample in the headspace sample bottle flush the corresponding gas inlet pipeline and the quantitative tube under the effect of the self-headspace pressure, then close the two-way intake valve, open the two-way exhaust valve, and the vacuum pump will extract the quantitative ring, then close again the two way air outlet valve, open the two way air inlet valve uses sample gas to wash the ration ring, so the flow is many to wash several times, can improve the cleanliness of admission line, improves and advances kind precision, when washing the completion back, keeps the two way air inlet valve open the two way air outlet valve open the three way vent valve with the vacuum pump is closed, and unnecessary sample gas will pass through in three way vent valve's the gas vent discharges into the atmosphere, makes the sample gas of treating the analysis exist with the form of ordinary pressure in the ration ring, accomplishes the sample and loads the process. Because the volumes of the gas inlet pipeline and the quantitative ring are very small relative to the volume of the gas sample bottle, the volume required by automatic sample injection analysis can be met under the condition of very small sample amount by adopting a vacuumizing auxiliary self-headspace sample injection mode.

The cylinder is fixed on the positioning system; and is connected with the cylinder driving device;

the injection device is connected with the air cylinder;

the cylinder driving device, the three-way needle inlet valve, the three-way needle outlet valve, the two-way air inlet valve, the six-way sample inlet valve, the two-way air outlet valve, the three-way exhaust valve, the vacuum pump and the gas chromatograph are respectively electrically connected with the control system.

Preferably, the cylinder driving device includes: a three-way needle inlet valve, a three-way needle outlet valve and an air pressure stabilizing valve; the air outlet of the three-way needle inserting valve and the air outlet of the three-way needle withdrawing valve are respectively communicated with the air cylinder; the three-way needle inserting valve air inlet and the three-way needle withdrawing valve air inlet are respectively communicated with the air outlet of the air pressure stabilizing valve; the air inlet of the air pressure stabilizing valve is communicated with compressed air; the three-way needle inlet valve and the three-way needle outlet valve are respectively electrically connected with the control system;

the cylinder includes: a cylinder barrel, a piston and a cylinder shaft; the piston divides the cylinder into an upper air chamber and a lower air chamber;

the upper air chamber is communicated with the air outlet of the three-way needle inserting valve, and the lower air chamber is communicated with the air outlet of the three-way needle withdrawing valve;

the top of the cylinder barrel is provided with a needle position probe; the piston is provided with a needle position magnet; the needle position probe is electrically connected with the control system;

one end of the cylinder shaft is connected with the piston, and the other end of the cylinder shaft is connected with the injection device.

The injection device comprises: the device comprises a needle seat and a sample injection needle, wherein one end of the needle seat is connected with the air cylinder shaft, the other end of the needle seat is connected with the sample injection needle, and the inside of the needle seat is communicated with an air inlet of the two-way air inlet valve.

Wherein, the needle file both ends are the external screw thread, and the centre is hexagonal prism, upper portion external screw thread connection cylinder shaft, cylinder shaft and piston structure as an organic whole, and threaded injection needle in lower part external screw thread connection inside. A gas channel hole which is 90 degrees is arranged at the center of the inner part of the external thread of the connecting needle head and the center of one surface of the hexagonal prism in the needle base, and an air inlet channel is arranged on the prismatic surface. The inside of the sample injection needle is provided with a thread which is connected on the needle base, and a rectangular small hole is processed on the side wall of the needle tube close to the needle point, so that the needle head is prevented from generating foam to block the needle tube when the rubber sealing gasket is punctured. A conical sealing ring with a round hole in the middle is arranged in the needle head, and the thread end face of the needle seat is attached to the conical surface in the needle head with the side hole to form a sealed space.

Preferably, the positioning system comprises: the device comprises a sample disc, a gear disc, a cylinder arm, a middle shaft device, a side shaft device, a sliding arm, a gear and a power device;

the sample disc and the gear disc are both fixedly arranged on the middle shaft device, and the sample disc is positioned at the upper part of the gear disc; the sample tray is provided with bottle position holes which are arranged in an involute way; a sliding groove corresponding to the bottle position hole is formed in the disc surface of the gear disc;

the middle shaft device and the side shaft device are both vertically arranged on the bottom plate;

one ends of the sliding arm and the cylinder arm are both arranged on the paraxial device, and the sliding arm is parallel to the cylinder arm; a guide head is fixedly arranged on the sliding arm and slides in the sliding groove; the cylinder is fixed on the cylinder arm;

the gear with power device is connected, just the gear with the toothed disc looks adaptation.

Further, the slider arm includes: the upper sliding sheet and the lower sliding sheet are fixedly arranged on the paraxial device, the upper sliding sheet and the lower sliding sheet are PCB (printed circuit board) welded with components, and the guide head is arranged on the upper sliding sheet;

the upper sliding sheet and the lower sliding sheet are electrically connected with a control system through conducting wires respectively;

the starting position and the ending position of the sliding chute are respectively provided with a starting magnet and a final magnet; the upper slide is provided with a start position probe and a final position probe; and the initial probe and the final probe are electrically connected with the control device.

A capacitive grid displacement sensor is welded on the upper sliding sheet, the head of the capacitive grid displacement sensor is positioned in the guide head, and a capacitive grid circuit is adhered inside the sliding chute; and the capacitive grid displacement sensor is powered by the upper slide.

Further, the bottom bracket device comprises: a middle shaft bearing part and a middle shaft rod; the lower end of the middle shaft lever is assembled in the middle shaft bearing part; the sample disc and the gear disc are fixedly sleeved on the middle shaft rod;

the paraxial device comprises: a side shaft bearing part and a side shaft rod; the lower end of the side shaft rod is assembled in the side shaft bearing part; the upper slide sheet and the lower slide sheet are fixedly sleeved on the side shaft rod;

and the middle shaft bearing part and the side shaft bearing part are vertically arranged on the bottom plate.

Furthermore, the square cylinder fixing hole in the cylinder arm is used for fixing the square cylinder, and the large round hole in the middle can enable the cylinder shaft and the connected needle seat to smoothly pass through. There is a cylinder arm locking hole at the right-hand member of cylinder arm, can locate the cylinder arm on the other axostylus axostyle just through this hole, the cylinder arm can slide from top to bottom at other axostylus axostyle, when sliding to suitable high position, can use the long screw in locking screw hole with the cylinder arm clamp locking on other axostylus axostyle, there is a locking hole breach in the another side that corresponds the locking hole in addition, can make the centre gripping deformation strength distribution of locking even, change the centre gripping and screw up more easily.

Furthermore, the injection device also comprises an adjusting rod and a bottle blocking piece, wherein the bottle blocking piece is a metal piece provided with a center and two side holes; the cylinder is fixed on the cylinder arm through an adjusting rod; the regulation pole is two at least, and the symmetry sets up, it includes to adjust the pole: the nut comprises a screw rod, a nut and a screw, wherein one end of the screw rod is provided with an external thread, the outer part of one end of the screw rod is provided with a hexagonal prism, and the inner part of the hexagonal prism is provided with an internal thread; one end of the external thread of the screw rod penetrates through the cylinder arm to be connected with the cylinder and is locked by a nut; the screw penetrates through the side hole of the bottle blocking piece and is screwed into the internal thread of the screw rod.

Specifically, the adjusting rod is in the shape of a long rod, one end of the adjusting rod is provided with an external thread, the outer part of the other end of the adjusting rod is provided with a hexagonal prism, and the inner part of the hexagonal prism is provided with an internal thread; the bottle blocking piece is a cuboid metal piece, a small round hole which can allow the sample injection needle head to smoothly pass through is arranged in the center of the piece, and the small hole also has the function of righting the needle head; the middle of the left end and the right end of the bottle blocking piece are provided with a screw hole, the screw penetrates through the internal thread of the bottle blocking piece screwed in the adjusting rod, a hexagonal nut is screwed in the external thread of the adjusting rod firstly to serve as a lock, and then the external thread of the adjusting rod penetrates through the fixing hole in the cylinder arm and is screwed in the thread fixing hole in the square cylinder.

When the height of keeping off the bottle piece is adjusted to needs, loosen fixed screw and lock nurse earlier, hexagonal prism on the rotatory regulation pole again, adjust pole external screw thread precession cylinder screw hole during clockwise rotation, the adjustment piece position rises, adjust pole external screw thread back-out cylinder screw hole during counter-clockwise rotation, the adjustment piece position reduces, adjust to just hide in the aperture that keeps off the bottle piece for the accuracy when the syringe needle is in the top position needle point, and the regulation pole position on both sides is equally high, again in proper order fasten lock nurse can with the screw.

Preferably, the middle shaft bearing part and the side shaft bearing part are the same and each comprise: a bearing seat, a bearing and a shaft barrel; the upper part of the bearing seat is provided with an opening, is cylindrical and hollow, and the bottom of the bearing seat is provided with an external thread interface which is screwed on the bottom plate; an annular recess is formed in the bottom connecting bottom plate at the bottom of the bearing sleeve; the two bearings are respectively positioned at the upper end and the lower end in the bearing seat, the shaft cylinder is hollow and cylindrical, the inner diameter of the shaft cylinder is larger than that of the bearings, the shaft cylinder is positioned between the two bearings, and the two end surfaces of the shaft cylinder are in close contact with the end surfaces of the inner rings of the upper bearing and the lower bearing; the middle shaft lever and the side shaft lever are positioned inside the bearing and the shaft barrel.

Preferably, the sample disc and the gear disc are sleeved on the middle shaft rod through a disc seat, and the disc seat comprises: the locking device comprises a locking hole positioned in the center, screw holes positioned at four corners and locking nail holes positioned at one side, wherein a locking hole notch is formed in one side of the locking hole, a through locking hole through groove is formed in the other side corresponding to the locking hole notch, and the locking nail holes are perpendicular to the through locking hole through groove; and screw holes consistent with the screw holes are arranged on the gear disc and the sample disc.

Specifically, the bearing seats of the two shafts have the same structure, the upper parts of the two shafts are opened and are cylindrical and hollow, and the bottoms of the two shafts are provided with external thread interfaces which can be screwed on the bottom plate. An annular recess is formed in the bottom connecting bottom plate at the bottom of the bearing sleeve, so that the contact surface between the shaft and the bottom plate is reduced by the outer ring of the bearing seat, and the bearing seat is kept in close contact with the bottom plate and is perpendicular to the bottom plate; two small round holes are formed in the side wall of the middle of the bearing seat, and a rod-shaped tool (such as a screwdriver) can be conveniently inserted into the holes to assist in screwing or unscrewing the threads of the bearing seat.

The bottom end of the middle shaft rod is sequentially provided with a bearing, a shaft cylinder and another bearing in a matching and penetrating mode, the inner ring of the bearing is in close contact fit with the middle shaft rod, the shaft cylinder is in a hollow cylindrical shape, two end faces of the shaft cylinder are in contact with the end face of the inner ring of the bearing but are not in contact with the middle shaft rod, the upper bearing and the lower bearing are supported, the middle shaft rod is kept vertical, and the middle shaft rod, the inner ring of the bearing and the shaft cylinder can rotate smoothly at the same time. Then, a middle shaft rod with bearings and a shaft cylinder penetrating through is pressed into the bearing seat, so that outer rings of the upper bearing and the lower bearing are in close contact with the inner wall of the bearing seat, and the middle shaft rod can smoothly rotate in the bearing seat. The assembly mode of the side shaft is the same as that of the middle shaft.

Furthermore, a long strip-shaped fillet groove is formed in the middle shaft rod, a standard fillet flat key can be placed in the fillet flat key, a half height of the fillet flat key protrudes out of the surface of the shaft rod after the fillet flat key is placed in the fillet flat key, when the disc shaft sleeve of the sample disc is arranged on the middle shaft, the protruding fillet flat key blocks a notch in the disc shaft sleeve, and a hand-screwed lock nail is screwed into the top of the disc shaft sleeve to accurately position the sample disc on the middle shaft rod.

Preferably, the sample disc comprises an upper disc, a middle disc, a lower disc, a single-pass copper column, a double-pass copper column and a fixing screw; the middle disc is arranged between the upper disc and the lower disc and is connected with the upper disc through a single-pass copper column and a double-pass copper column and a fixing screw; the upper disc and the middle disc are identical in structure, a middle shaft hole is formed in the center of each upper disc, and bottle position holes which are arranged in an involute mode are formed in the disc surface; the lower disk is the same as the upper disk except that the bottle position hole is not arranged.

Preferably, the control system comprises a control panel and a single chip microcomputer, and the control panel is connected with the single chip microcomputer through a flat cable; the positioning system, the three-way needle inlet valve, the three-way needle outlet valve, the two-way air inlet valve, the six-way sample inlet valve, the two-way air outlet valve, the three-way exhaust valve, the vacuum pump and the cylinder driving device are respectively connected with the single chip microcomputer through electric leads and controlled by a program in the single chip microcomputer.

According to the technical scheme, compared with the prior art, the invention has the following beneficial effects:

the invention can realize

1) And the positioning is fast, high-precision and accurate. The positioning speed can reach 1 m/s high speed by adopting an involute combined with a capacitive gate circuit and a motor speed change technology, the mobile positioning can be realized only by a few seconds, the displacement detection precision is improved to 0.02 mm, the speed can be controlled and reduced when the target bottle position is reached quickly, the inertia influence caused by high-speed movement is prevented, and the positioning is accurate and efficient;

2) the sample injector can control the six-way sample injection valve and the gas chromatogram, adopts a valve switching sample injection mode, so that the sample injector can be suitable for the gas chromatograms with various models and sample injection modes, and can realize automatic sample injection only by connecting the 6 th gas outlet of the six-way sample injection valve into a sample injection port corresponding to the chromatogram and controlling the start of the chromatogram;

3) the sample injector adopts a self-headspace sample injection mode, so that the sample storage space and the occupied volume of the sample injector are greatly saved. The gas sample is hermetically stored in the headspace sample bottle in a compression mode, and the pressure in the sample bottle provides power for flushing a pipeline and sampling when sampling, so that the self-headspace sampling is realized. The compressed storage of the gas ensures that the sample introduction can be realized only by a small amount of gas samples, the sample introduction device is also suitable for the condition of small sample amount, and the sample introduction device can provide a large amount of sample positions under the condition of a certain volume, thereby improving the automation efficiency;

4) the flow-limiting filter is adopted, so that the gas sample is ensured to replace the old sample in a steady-flow slow-speed propelling mode, the gas inlet pipeline is cleaned by using less gas, the sample introduction precision is improved, and the cross contamination of the sample is prevented;

5) except providing the appearance mode of advancing from the headspace, still use the vacuum pump to assist and advance the appearance from the headspace for few gas sample also can realize advancing the appearance from the headspace, can also improve abluent efficiency of pipeline and cleanliness factor simultaneously. The method comprises the following steps of using a vacuum pump to assist in sample introduction from a headspace, firstly using the vacuum pump to extract vacuum from an air inlet pipeline and a quantitative tube, then using sample gas to fill a pipeline from the headspace for cleaning, circulating for several times, and finally using a self-headspace technology to fill the quantitative tube.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic diagram of the overall structure of the present invention;

FIG. 2 is a schematic diagram of the gas circuit system of the present invention, in which the six-way sampling valve is closed;

FIG. 3 is a schematic diagram of the six-way sampling valve in an open state;

FIG. 4 is a schematic view of a cylinder arm according to the present invention;

FIG. 5 is a schematic view of the gear plate of the present invention;

FIG. 6 is a schematic diagram of the structure of the upper disk of the sample disk of the present invention;

fig. 7 is a schematic view of the structure of the disk seat of the present invention.

Wherein, in the figure,

1-a control panel; 2, a singlechip; 3-three-way needle inlet valve; 4-three-way needle valve withdrawal; 5-air pressure maintaining valve; 6-three-way exhaust valve; 7-two-way vent valve; 8-two-way intake valves; 9-a vacuum pump; 10-six-way sample injection valve; 101-a dosing tube; 11-gas chromatography; 12-a flow restricting filter; 13-sample tray; 131-upper disc; 132-middle disc; 133-lower disc; 134-shaft sleeve hole; 135-bottle position hole; 14-a gear disc; 141-a chute; 142-home magnet; 143-final position magnet; 144-a capacitive gate circuit; 15-cylinder; 151-piston; 152-upper air chamber; 153-lower air chamber; 16-a cylinder arm; 17-a middle shaft rod; 18-a side shaft rod; 19-a needle seat; 20-a sample injection needle; 21-needle position probe; 22-a slider arm; 221-upper sliding sheet; 222-a lower slide; 23-a guide head; 24-an air intake duct; 25-a base plate; 26-a motor; 27-a gear; 28-adjusting rod; 29-bottle blocking sheet; 30-a disk seat; 31-a bearing seat; 32-a bearing; 33-shaft cylinder.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Examples

As shown in fig. 1-7, the apparatus of the present invention comprises the following main components:

1) the control system comprises: the device mainly comprises a control panel 1 and a single chip microcomputer 2 (designed and customized based on macro-crystal STC12C 5A); the control panel 1, the motor 26 (planetary gear motor), the six-way sample injection valve 10, the vacuum pump 9, the two-way gas outlet valve 7, the two-way gas inlet valve 8, the three-way gas outlet valve 6, the gas chromatograph 11, the needle position probe 21, the three-way needle inlet valve 3, the three-way needle withdrawing valve 4, the upper slide 221 and the lower slide 222 are respectively connected with the singlechip 2 by electric leads and controlled by a program in the singlechip 2. The control panel 1 is connected with the singlechip 2 by a flat cable, and is provided with a liquid crystal display for displaying information and keys for inputting parameters or commands. The final position probe, the initial position probe and the needle position probe 21 are all Hall sensors capable of acquiring position information through magnetic induction; the upper sliding sheet 221 and the lower sliding sheet 222 are long rectangular PCB circuit boards with components welded thereon, the final probe, the initial probe and the capacitive grating displacement sensor are welded on the upper sliding sheet 221 and are all powered by the upper sliding sheet 221, and the head of the capacitive grating displacement sensor is located in the guide head 23. The grid circuit 144 is adhered to the slide groove 141 of the gear plate 14 by a back adhesive.

2) Gas path system (as shown in fig. 2):

the three-way exhaust valve 6, the three-way needle inlet valve 3 and the three-way needle outlet valve 4 are all normally closed two-position three-way electromagnetic valves, the valves are provided with three interfaces which are respectively an air inlet, an air outlet and an air outlet, the air outlet is positioned at the top of the valve, the air inlet is sealed by a sealing gasket in the closed state of the valve without electrifying, air can not pass through, and the air outlet is communicated with an air passage of the air outlet; the air inlet is communicated with the air outlet and the air outlet is not communicated when the valve is in the electrified state; the two-way air inlet valve 8 and the two-way air outlet valve 7 are normally closed two-position two-way electromagnetic valves, only have an air inlet and an air outlet, the air inlet and the air outlet are not communicated when the valves are not electrified and closed, and the air inlet and the air outlet are communicated when the valves are electrified and opened; the six-way sampling valve is provided with a quantitative tube 101 which is respectively connected with the No. 2 and No. 5 interfaces of the six-way sampling valve 10, and a sample to be analyzed is quantitatively stored in the tube. The gas path connection is as shown in figure 2, the gas inlet of the two-way gas inlet valve 8 is connected with the needle seat 4, the gas outlet thereof is connected with the flow-limiting filter 12, and the other end of the flow-limiting filter 12 is connected with the 4 th interface of the six-way sample inlet valve 10; the air outlet of the two-way air outlet valve 7 is connected with the 3 rd interface of the six-way sample injection valve 10, the air inlet thereof is connected with the air outlet of the three-way exhaust valve 6, the air inlet of the three-way exhaust valve 6 is connected with the vacuum pump 9, and the air outlet thereof is communicated with the atmosphere; the air outlet of the three-way needle inlet valve 3 is connected with the upper air chamber 152 of the square air cylinder 15, the air inlet of the three-way needle inlet valve is connected with the three-way joint, and the air outlet of the three-way needle inlet valve is communicated with the atmosphere; the air outlet of the three-way needle withdrawing valve 4 is connected with the lower air chamber 153 of the square air cylinder 15, the air inlet of the three-way needle withdrawing valve is connected with the other interface of the three-way joint, and the air outlet of the three-way needle withdrawing valve is communicated with the atmosphere;

fig. 2 also shows the structure of the needle injection device. The both ends of the needle seat 19 are external threads, the middle part is a hexagonal prism, the upper part is connected with an air cylinder shaft through external threads, the lower part is connected with a sample injection needle (side hole needle head) with internal threads through external threads, a gas channel hole which is 90 degrees is arranged at the center of one of the surfaces of the internal center of the external threads of the needle seat 19 and the hexagonal prism, and a gas pipe joint (gas inlet pipe 24) is arranged on the prismatic surface. The side hole needle head is internally provided with a thread which is connected on the needle seat 19, and the side wall of the needle tube close to the needle point is provided with a rectangular small hole which prevents the needle head from generating broken foam to block the needle tube when the needle head pierces the rubber sealing gasket. A conical sealing ring with a round hole in the middle is arranged in the needle head, and the threaded end face of the needle seat 19 is attached to the conical surface in the needle head with the side hole to form a sealed space.

The adjusting rod 28 is in the shape of a long rod, one end of the adjusting rod is provided with external threads, and the outer part of the adjusting rod is provided with hexagonal prisms and internal threads; the bottle stopper 29 is a cuboid metal sheet, a small round hole which can allow the side hole needle head to smoothly pass through is arranged in the center of the sheet, and the small hole has the function of righting the needle head; the middle of the left end and the right end of the bottle blocking piece 29 is provided with a screw hole, a screw passes through the bottle blocking piece 29 and is screwed into the internal thread of the adjusting rod 28, a hexagonal nut is screwed into the external thread of the adjusting rod 28 to serve as a lock, and then the external thread of the adjusting rod 28 passes through the fixing hole in the cylinder arm 16 and is screwed into the thread fixing hole in the square cylinder 15. Fig. 4 shows the structure of cylinder arm 16. When the height of keeping off bottle piece 29 needs to be adjusted, loosen fixed screw and lock nurse earlier, hexagonal prism on the rotatory regulation pole 28 again, the cylinder screw hole is screwed into to the 28 external screw threads of clockwise rotation regulation pole, the regulation piece position rises, the 28 external screw threads of anticlockwise rotation regulation pole screw out cylinder screw hole, the regulation piece position reduces, it just hides in the aperture that keeps off bottle piece 29 for accurate to adjust the needle point when the syringe needle is in the top position, and the regulation pole 28 position on both sides is the same high, it can to lock nurse and screw in proper order again.

Compressed air supplies air to the three-way needle inlet valve 3 and the three-way needle outlet valve 4 after passing through the air pressure stabilizing valve 5 and the three-way joint, as shown in figure 2, when a needle needs to be inserted, the three-way needle inlet valve 3 is opened, the compressed air enters the upper air chamber 152 through an air inlet at the upper part of the square cylinder 15, the lower air chamber 153 is at normal pressure, the compressed air pushes the piston 151 and the cylinder shaft in the cylinder to move downwards and drives the needle seat 19 and the side hole needle head to move downwards together, the needle head punctures a rubber sealing pad of a top empty bottle below and extends into the top empty bottle, at the moment, the three-way needle inlet valve 3 is closed, the compressed air in the upper air chamber 152 is discharged through an air outlet of the three-way needle inlet valve 3, the normal pressure state in the upper. When the needle needs to be withdrawn, the three-way needle withdrawing valve 4 is opened, compressed gas enters the lower air chamber 153 of the square air cylinder 15, the piston 151 and the air cylinder are pushed to move axially upwards, the needle seat 19 and the side hole needle head are driven to move upwards, the side hole needle head is positioned in the headspace bottle at the moment, the headspace bottle is driven to move upwards due to the friction force between the rubber sealing gasket in the headspace bottle cap and the needle head, after the headspace bottle cap is contacted with the bottle blocking piece 29, the bottle blocking piece 29 prevents the headspace bottle from moving further upwards, the side hole needle head overcomes the friction resistance, is pulled out from the rubber sealing gasket and hides the needle head in the bottle blocking piece 29, and the headspace bottle falls back under the action of gravity. When the piston 151 rod moves to the uppermost part, the small circular magnet at the center of the top of the piston 151 rod is close to the needle position probe 21 fixed at the top outside the square cylinder to indicate that the needle head has moved to the right position, at this time, the system closes the three-way needle withdrawing valve 4, and the compressed gas in the lower gas chamber 153 is discharged from the exhaust port of the three-way needle withdrawing valve 4 to complete the needle withdrawing action.

Figure 4 shows a cross-section of the cylinder arm 16 with a square cylinder fixing hole for the square cylinder and a large central circular hole for the cylinder shaft and the associated needle seat 19 to pass through smoothly. The left end of the cylinder arm 16 is provided with a cylinder arm 16 locking hole, the cylinder arm 16 can be just sleeved on the side shaft rod 18 through the hole, the cylinder arm 16 can slide up and down on the side shaft rod 18, when the cylinder arm slides to a proper height position, a long screw can be screwed into the locking threaded hole to clamp and lock the cylinder arm 16 on the side shaft rod 18, and the other side corresponding to the locking hole is also provided with a locking hole notch, so that the clamping deformation force of locking can be uniformly distributed, and the clamping and the screwing are easier.

3) Positioning system

Fig. 5 shows a structural diagram of the gear plate 14, and fig. 5 shows a structural diagram of the disk plate 131 on the sample plate 13. As shown in fig. 4, the gear plate 14 is disc-shaped, and has a large circular hole and 4 chassis fixing holes at the center, the gear plate 14 can be locked on the plate holder 30 by screws, and the plate holder 30 is locked on the central shaft by long screws. A ring of teeth are uniformly distributed on the outer ring of the gear disc 14. A slide groove 141 is formed in an involute shape on the front surface of the gear plate 14, and a cylindrical start magnet 142 and a cylindrical end magnet 143 are embedded in a start position of an outer ring of the slide groove 141 and an end position of an inner ring of the slide groove 141, respectively, to indicate a start position and an end position of the slide groove 141. A capacitive gate circuit 144 with a back adhesive is adhered to the middle inside the sliding slot 141 to indicate the displacement of the slider in the sliding slot 141.

FIG. 6 is a structural diagram of the disk 131 on the sample disk 13. In the middle of the upper disc 131, there are a large circle (a boss hole 134) and four screw fixing holes, and screws can be used to fix the disc to the seat 30, and then the seat 30 is locked to the boss by long screws. Middle disk 132 is constructed the same as upper disk 131, while the bottom disk is identical to upper disk 131 except that it does not have vial position holes 135.

Fig. 7 is a schematic sectional view of the tray 30. The upper plate 131 or the lower plate 133 can be fixed to the hub 30 by screws, the shaft sleeve passes through the locking hole, and the hub 30 of the sample plate 13 can be clamped and locked on the shaft sleeve by screwing the locking pin into the locking hole.

The structure of the sample disk 13 is shown in fig. 1, and the sample disk 13 mainly comprises an upper disk 131, a middle disk 132, a lower disk 133, a disk shaft sleeve, a disk seat 30, a single-pass copper column, a double-pass copper column and a fixing screw. As shown in fig. 5, four screw holes are respectively formed on the outer ring of the upper disc 131, the upper part of the upper disc 131 is connected with a single-pass copper column by screws, the upper disc 131 is clamped between the screws and the single-pass copper column, the middle disc 132 is clamped between the screw end of the single-pass copper column and a double-pass copper column, the bottom disc is clamped between the screws and the double-pass copper column, the outer rings of the three discs are connected by four single-pass copper columns, the double-pass copper column and locking screws, and the upper disc 131 and the lower disc 133 are fixed on the disc seat 30 by screws at the central part of the disc, and then the disc shaft sleeve is arranged on the upper disc seat 30, the middle disc 132 and the lower disc seat 30 in a penetrating manner and is locked on the disc shaft seat by the screws of the upper disc seat 30 and the lower disc seat 30.

The structure of the middle shaft rod 17 and the side shaft rod 18 is shown in fig. 1. The middle shaft comprises a bearing seat 31, a bearing 32, a shaft barrel 33, a shaft seat hole, a middle shaft rod 17, a key groove and a hand-screwed locking nail. The side bearing comprises a bearing seat 31, a bearing 32, a shaft barrel 33, a shaft seat hole and a side shaft rod 18; the bearing seats 31 of the two shafts have the same structure, the upper parts of the bearing seats are opened and are cylindrical and hollow, and the bottom of the bearing seats are provided with external thread interfaces which can be screwed on the bottom plate 25. An annular recess is formed in the bottom connecting bottom plate 25 of the bearing sleeve, so that the contact surface between the shaft and the bottom plate 25 is reduced by the outer ring of the bearing seat 31, and the bearing seat 31 is kept in close contact with the bottom plate 25 and is perpendicular to the bottom plate 25; two small round holes are arranged on the side wall of the middle part of the bearing seat 31, so that a rod-shaped tool (such as a screwdriver) can be conveniently inserted into the holes to assist in screwing or unscrewing the bearing seat 31. The assembly structure of the middle shaft and the side shaft is also shown in fig. 1, a bearing is sequentially arranged at the bottom end of the middle shaft rod 17 in a penetrating manner, the shaft cylinder 33 and the other bearing, the inner ring of the bearing is in close contact fit with the middle shaft rod 17, the shaft cylinder 33 is in a hollow cylindrical shape, two end faces of the shaft cylinder 33 are in contact with the end faces of the inner ring of the bearing but not in contact with the middle shaft rod 17, the upper bearing and the lower bearing are supported, the middle shaft rod 17 is kept vertical, and the middle shaft rod 17, the inner ring of the bearing and the shaft cylinder 33 can simultaneously rotate smoothly. Then, the middle shaft rod 17 with the bearings and the shaft cylinder 33 inserted is pressed into the bearing seat 31, so that the outer rings of the upper and lower bearings are in close contact with the inner wall of the bearing seat 31, and the middle shaft rod 17 can smoothly rotate in the bearing seat 31. The assembly mode of the side shaft is the same as that of the middle shaft. A long strip-shaped round corner groove is formed in the middle shaft rod 17, a standard round corner flat key can be placed in the round corner flat key, a half height of the round corner flat key protrudes out of the surface of the shaft rod after the round corner flat key is placed in the round corner flat key, when the disc shaft sleeve of the sample disc 13 is sleeved on the middle shaft, the protruding round corner flat key clamps a notch in the disc shaft sleeve, and a hand is screwed into the top of the disc shaft sleeve to screw a locking nail, so that the sample disc 13 is accurately positioned on the middle shaft rod 17.

The positioning principle is as follows: during assembly, the cylinder arm 16 and the slide arm 22 are coaxially fixed on the side shaft rod 18, the vertical position of the needle head is consistent with that of the guide head 23, and the sample disc 13 and the gear disc 14 are also coaxially fixed on the middle shaft rod 17. When positioning is needed, the single chip microcomputer 2 detects the position in the slide arm 22 where the guide head 23 is located according to the start position probe on the slide arm 22, when the position does not meet a specific position, the single chip microcomputer 2 drives the planetary gear motor 26 to rotate, the gear 27 on the motor 26 drives the gear disc 14 to rotate, the sample disc 13 fixed on the central shaft coaxially rotates, and because the guide head 23 on the slide arm 22 is located in the slide groove 141 of the gear disc 14, the guide head 23 is pushed by the slide groove 141 distributed in an involute shape, the guide head 23 pushes the slide arm 22, the slide arm 22 pushes the side shaft rod 18 to rotate, the side shaft rod 18 drives the cylinder arm 16 coaxially fixed to rotate, the cylinder arm 16 drives the needle head to move to the upper side of the corresponding slide groove 141, when the guide head 23 slides in the slide groove 141, the grid displacement sensor in the guide head 23 records the displacement distance, when the distance of movement is reached, the movement is stopped, so that the needle position is stopped at the, and completing the positioning of the needle position.

And because the grooves of the gear disc 14 are distributed in an involute way, the speed difference of the guide head 23 between the outer ring and the inner ring of the chute 141 is large during gear transmission, the single chip microcomputer 2 system records the position of the disc according to an involute function, adjusts the rotating speed of the motor 26, controls the moving speed of the guide head 23 in the chute 141, runs at a high speed when the guide head is far away from a target bottle position and reduces the speed when the guide head is close to the target bottle hole position, and the positioning precision is prevented from being influenced by overlarge rotating inertia. The highest moving speed can reach 1.8 m/s and the displacement resolution can reach 0.02 mm after the capacitive grating is adopted for positioning, so that the position of the sample bottle can be quickly and accurately positioned at variable speed.

4) Main flow for realizing functions

When the planetary gear motor 26 is rotated and positioned to a corresponding sample bottle position, two self-headspace sample injection processes are available:

(1) a common self-headspace sample introduction process: the singlechip 2 controls to open the three-way needle inlet valve 3, compressed air enters the upper air chamber 152 of the square cylinder 15 to push the piston 151, the piston drives the needle seat 9 and the sample injection needle 20, the sample injection needle 20 pierces a top empty bottle sealing gasket to enter the inside of the top empty bottle, at the moment, the three-way needle inlet valve 3 is closed, the compressed air in the upper air chamber 152 is discharged from an exhaust port of the three-way needle inlet valve 3, and the air chamber 152 recovers to normal pressure; then the singlechip opens the two-way air inlet valve 8 and the two-way air outlet valve 7, the compressed sample gas in the headspace sample bottle passes through the side hole of the sample injection needle, the L-shaped channel in the needle seat 9, the two-way air inlet valve 7, the flow limiting filter, the 4 th interface, the 5 th interface, the quantifying pipe 101, the 2 nd interface and the 3 rd interface on the six-way sample injection valve 10 in sequence under the action of the self pressure, and then enters the atmosphere through the exhaust ports of the two-way air outlet valve 7 and the three-way exhaust valve 6, in the process, the flow limiting filter can filter particles in the sample and limit the flow rate of the gas, so that the gas in the air inlet pipeline is in a steady flow state to push and replace the gas in the original pipeline into the atmosphere, and simultaneously the sample gas is used for flushing the air inlet pipeline until the pressure in the headspace bottle is consistent with the external atmospheric pressure, the singlechip 2 respectively closes the two-way air inlet valve 8 and the, the singlechip 2 opens the three-way needle withdrawing valve 4, compressed air enters the lower air chamber 153 of the square air cylinder 15, a piston in the air cylinder is pushed to move upwards, a needle seat 9, a sample injection needle and a headspace bottle are driven to move upwards, the headspace bottle is limited by an upper bottle blocking piece to enable the sample injection needle to be pulled out of the headspace bottle, the headspace bottle returns under the action of gravity, when the piston reaches the top end of the air cylinder, a needle position probe on the square air cylinder 10 detects that the needle head returns, the needle withdrawing electromagnetic valve 4 is closed, the compressed air in the lower air chamber 153 is exhausted from an exhaust port of the three-way needle withdrawing valve 4, and the air pressure in the lower air chamber returns to normal pressure; then the single chip microcomputer 2 controls to open the six-way sampling valve 10, switches to the gas flow path in fig. 3, and simultaneously the single chip microcomputer 2 controls the gas chromatograph 11 to start the analysis function, at this time, the high-purity carrier gas (such as nitrogen) sequentially flows through the 1 st interface, the 2 nd interface, the quantitative tube 101, the 5 th interface and the 6 th interface on the six-way sampling valve 10, brings the sample to be analyzed in the quantitative tube 101 under normal pressure into the gas chromatograph 11 for sampling analysis, and after all the sample gas is brought into the gas chromatograph 11 within a certain time, the single chip microcomputer 2 closes the six-way sampling valve 10, returns to the gas flow path shown in fig. 2, and completes one-time gas sampling. Then the singlechip 2 controls the sample tray to move to the next bottle position, the singlechip 2 detects whether the gas chromatograph 11 completes the analysis of the previous sample and prepares, and when the last sample is detected to complete the analysis and prepare, the singlechip 2 automatically controls the sample injection again until the set sample injection number is completed.

(2) Vacuum cleaning auxiliary self-headspace sample injection process: the process uses a vacuum pump to combine with a self-headspace cleaning air inlet pipeline and a quantitative tube, and comprises the working steps that a singlechip 2 controls to open a three-way needle inlet valve 3, compressed air enters an upper air chamber 152 of a square cylinder 15 to push a piston 151, the piston drives a needle seat 9 and a sample injection needle 20, the sample injection needle 20 pierces a top-headspace bottle sealing gasket to enter the inside of the top-headspace bottle, the three-way needle inlet valve 3 is closed at the moment, compressed air in the upper air chamber 152 is discharged from an exhaust port of the three-way needle inlet valve 3, and the air chamber 152 recovers to normal pressure; then the single chip microcomputer opens the vacuum pump 9, the three-way exhaust valve 6 and the two-way exhaust valve 7, the vacuum of the air inlet pipeline 24, the quantitative pipe 101 and the flow-limiting filter 12 from the two-way intake valve 8 to the vacuum pump 9 is extracted, then the two-way exhaust valve 7 is closed and the two-way intake valve 8 is opened, the compressed sample gas in the headspace sample bottle sequentially passes through the side hole of the sampling needle, the L-shaped channel in the needle seat 9, the two-way intake valve 7, the flow-limiting filter, the 4 th interface, the 5 th interface, the quantitative pipe 101, the 2 nd interface and the 3 rd interface on the six-way sampling valve 10 to the air inlet of the two-way exhaust valve 7 under the action of the self pressure; the above evacuation and cleaning processes may then be repeated as needed, with more cycles flushing the inlet duct 24 with sample gas being more thorough; after the circulation cleaning is finished, the vacuum pump 9 and the three-way exhaust valve 6 are kept in a closed state, the two-way intake valve and the two-way exhaust valve are kept in an open state, residual compressed sample gas in the headspace bottle sequentially flows through the sampling needle, the L-shaped channel in the needle base 9, the two-way intake valve 7, the flow limiting filter, the 4 th interface, the 5 th interface, the quantifying pipe 101, the 2 nd interface and the 3 rd interface on the six-way sampling valve 10 and then enters the atmosphere through the exhaust ports of the two-way exhaust valve 7 and the three-way exhaust valve 6, in the process, the flow limiting filter can filter particles in the sample and limit the flow rate of the gas, so that the gas in the gas inlet pipeline is in a steady flow state to push and replace the gas in the original pipeline into the atmosphere, the gas inlet pipeline is flushed by using the sample gas simultaneously until the pressure in the headspace bottle is consistent with the external atmospheric pressure, the two-way intake, at the moment, pure normal-pressure sample gas is filled in the quantitative tube, the single chip microcomputer 2 opens the three-way needle withdrawing valve 4, compressed air enters the lower air chamber 153 of the square air cylinder 15 to push a piston in the air cylinder to move upwards to drive the needle seat 9, the sample injection needle and the headspace bottle to move upwards, the headspace bottle is limited by the upper bottle stopper to enable the sample injection needle to be pulled out of the headspace bottle, the headspace bottle returns under the action of gravity, when the piston reaches the top end of the air cylinder, a needle position probe on the square air cylinder 10 detects that the needle head returns, the needle withdrawing electromagnetic valve 4 is closed, the compressed gas in the lower air chamber 153 is discharged from an exhaust port of the three-way needle withdrawing valve 4, and the air pressure in the lower air chamber returns to; then the single chip microcomputer 2 controls to open the six-way sampling valve 10, switches to the gas flow path in fig. 3, and simultaneously the single chip microcomputer 2 controls the gas chromatograph 11 to start the analysis function, at this time, the high-purity carrier gas (such as nitrogen) sequentially flows through the 1 st interface, the 2 nd interface, the quantitative tube 101, the 5 th interface and the 6 th interface on the six-way sampling valve 10, brings the sample to be analyzed in the quantitative tube 101 under normal pressure into the gas chromatograph 11 for sampling analysis, and after all the sample gas is brought into the gas chromatograph 11 within a certain time, the single chip microcomputer 2 closes the six-way sampling valve 10, returns to the gas flow path shown in fig. 2, and completes one-time gas sampling. Then the singlechip 2 controls the sample tray to move to the next bottle position, the singlechip 2 detects whether the gas chromatograph completes the analysis of the previous sample and prepares the sample introduction condition, and when the singlechip 2 detects that the analysis of the previous sample is completed and prepared, the singlechip 2 automatically controls the sample introduction again until the set sample introduction number is completed.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A self-headspace gas chromatography sample injector is characterized by comprising a control system, a gas circuit system, a positioning system and a bottom plate; the positioning system is electrically connected with the control system; the positioning system is fixed on the bottom plate;

the gas path system comprises a cylinder, a cylinder driving device, a two-way air inlet valve, a flow limiting filter, a six-way sample injection valve, a dosing pipe, a two-way air outlet valve, a three-way exhaust valve, a vacuum pump and an injection device;

the three-way needle inlet valve, the three-way needle withdrawing valve and the air pressure stabilizing valve are communicated through a three-way joint; the three-way needle inlet valve is communicated with an upper air chamber of the air cylinder; the three-way needle withdrawing valve is communicated with a lower air chamber of the air cylinder; the six-way sampling valve is communicated with the flow-limiting filter; the vacuum pump, the three-way exhaust valve, the two-way exhaust valve, the six-way sample injection valve, the flow limiting filter, the two-way intake valve and the injection device are communicated in sequence;

the 1 st interface of the six-way sample valve is connected with high-purity nitrogen, the six-way sample valve is provided with a quantitative pipe, two ends of the quantitative pipe are positioned at the 2 nd interface and the 5 th interface of the six-way sample valve, the 3 rd interface and the 4 th interface of the six-way sample valve are respectively connected with the two-way gas outlet valve and the flow limiting filter, and the 6 th interface of the six-way sample valve is connected with a gas chromatograph;

the cylinder is fixed above the positioning system; and is connected with the cylinder driving device;

the injection device is in threaded connection with the cylinder;

the cylinder driving device, the two-way air inlet valve, the six-way sample inlet valve, the two-way air outlet valve, the three-way exhaust valve and the vacuum pump are respectively and electrically connected with the control system.

2. The self-headspace gas chromatography sample injector of claim 1, wherein the cylinder drive comprises: a three-way needle inlet valve, a three-way needle outlet valve and an air pressure stabilizing valve; the air outlet of the three-way needle inserting valve and the air outlet of the three-way needle withdrawing valve are respectively communicated with the air cylinder; the three-way needle inserting valve air inlet and the three-way needle withdrawing valve air inlet are respectively communicated with the air outlet of the air pressure stabilizing valve; the air inlet of the air pressure stabilizing valve is communicated with compressed air; the three-way needle inlet valve and the three-way needle outlet valve are respectively electrically connected with the control system;

the cylinder includes: a cylinder barrel, a piston and a cylinder shaft; the piston divides the cylinder into an upper air chamber and a lower air chamber;

the upper air chamber is communicated with the air outlet of the three-way needle inserting valve, and the lower air chamber is communicated with the air outlet of the three-way needle withdrawing valve;

one end of the cylinder shaft is connected with the piston, and the other end of the cylinder shaft is connected with the injection device;

the top of the cylinder barrel is provided with a needle position probe; the piston is provided with a needle position magnet; the needle position probe is electrically connected with the control system;

the injection device comprises: the device comprises a needle seat and a sample injection needle, wherein one end of the needle seat is in threaded connection with a cylinder shaft, the other end of the needle seat is connected with the sample injection needle, and the inside of the needle seat is communicated with an air inlet of the two-way air inlet valve.

3. The self-headspace gas chromatography sample injector of claim 1, wherein the positioning system comprises: the device comprises a sample disc, a gear disc, a cylinder arm, a middle shaft device, a side shaft device, a sliding arm, a gear and a power device;

the sample disc and the gear disc are both fixedly arranged on the middle shaft device, and the sample disc is positioned above the gear disc; the sample tray is provided with bottle position holes which are arranged in an involute way; a sliding groove corresponding to the bottle position hole is formed in the disc surface of the gear disc;

the sample disc comprises an upper disc, a middle disc, a lower disc, a single-pass copper column, a double-pass copper column and a fixing screw; the middle disc is arranged between the upper disc and the lower disc and is connected with the upper disc through a single-pass copper column and a double-pass copper column and a fixing screw; the upper disc and the middle disc are identical in structure, a middle shaft hole is formed in the center of each upper disc, and bottle position holes which are arranged in an involute mode are formed in the disc surface; the lower disk is the same as the upper disk except that the bottle position hole is not arranged;

the middle shaft device and the side shaft device are both vertically arranged on the bottom plate;

one ends of the sliding arm and the cylinder arm are both vertically arranged on the paraxial device, and the sliding arm is parallel to the cylinder arm; a guide head is fixedly arranged on the sliding arm and slides in the sliding groove; the cylinder is fixed on the cylinder arm;

the gear with power device is connected, just the gear with the toothed disc looks adaptation.

4. The self-headspace gas chromatography sample injector of claim 3, wherein the slide arm comprises: the upper sliding sheet and the lower sliding sheet are fixedly arranged on the paraxial device, the upper sliding sheet and the lower sliding sheet are PCB (printed circuit board) welded with components, and the guide head is arranged on the upper sliding sheet;

the upper sliding sheet and the lower sliding sheet are electrically connected with a control system through conducting wires respectively;

the starting position and the ending position of the sliding chute are respectively provided with a starting magnet and a final magnet; the upper slide is provided with a start position probe and a final position probe; and the initial probe and the final probe are electrically connected with the control device.

5. The self-headspace gas chromatography sample injector of claim 3, wherein the upper slide plate is welded with a capacitive grid displacement sensor, the head of the capacitive grid displacement sensor is positioned in the guide head, and a capacitive grid circuit is adhered inside the sliding chute; and the capacitive grid displacement sensor is powered by the upper slide.

6. The self-headspace gas chromatography sample injector of claim 3, wherein the centershaft assembly comprises: a middle shaft bearing part and a middle shaft rod; the lower end of the middle shaft lever is assembled in the middle shaft bearing part; the sample disc and the gear disc are fixedly sleeved on the middle shaft rod;

the paraxial device comprises: a side shaft bearing part and a side shaft rod; the lower end of the side shaft rod is assembled in the side shaft bearing part; the upper slide sheet and the lower slide sheet are fixedly sleeved on the side shaft rod;

and the middle shaft bearing part and the side shaft bearing part are vertically arranged on the bottom plate.

7. The self-headspace gas chromatography sample injector of claim 6, wherein the center shaft bearing assembly and the side shaft bearing assembly are identical and each comprise: a bearing seat, a bearing and a shaft barrel; the upper part of the bearing seat is provided with an opening, is cylindrical and hollow, and the bottom of the bearing seat is provided with an external thread interface which is screwed on the bottom plate; an annular recess is formed in the bottom connecting bottom plate at the bottom of the bearing sleeve; the two bearings are respectively positioned at the upper end and the lower end in the bearing seat, the shaft cylinder is hollow and cylindrical, the inner diameter of the shaft cylinder is larger than that of the bearings, the shaft cylinder is positioned between the two bearings, and the two end surfaces of the shaft cylinder are in close contact with the end surfaces of the inner rings of the upper bearing and the lower bearing; the middle shaft rod and the side shaft rod penetrate through the bearing and the inner hole of the shaft cylinder.

8. The self-headspace gas chromatography sample injector of claim 6, wherein said sample disk and said gear disk are mounted on said central shaft by a disk mount, said disk mount comprising: the locking device comprises a locking hole positioned in the center, screw holes positioned at four corners and locking nail holes positioned at one side, wherein a locking hole notch is formed in one side of the locking hole, a through locking hole through groove is formed in the other side corresponding to the locking hole notch, and the locking nail holes are perpendicular to the through locking hole through groove; and screw holes consistent with the screw holes are arranged on the gear disc and the sample disc.

9. The self-headspace gas chromatography sample injector of any one of claims 1 to 8, wherein the control system comprises a control panel and a single-chip microcomputer, the control panel being connected to the single-chip microcomputer by a cable; the positioning system, the three-way needle inlet valve, the three-way needle outlet valve, the two-way air inlet valve, the six-way sample inlet valve, the two-way air outlet valve, the three-way exhaust valve and the vacuum pump are respectively connected with the single chip microcomputer through electric leads and controlled by a program in the single chip microcomputer.

10. The self-headspace gas chromatography sample injector of claim 9, wherein the self-headspace gas chromatography sample injector comprises two self-headspace sample injection modes, as follows:

firstly, directly from the headspace sampling mode, the sample gas is stored in the headspace sample bottle with the form of compression, when adopting direct headspace sampling mode, two admission valves reaches two admission valves are in the open mode, and three way exhaust valve is in the closed condition, when the introduction needle inserts in the headspace sample bottle, the compressed gas sample in the headspace bottle passes through in proper order under the effect of self pressure the needle file the current limiting filter six-way admission valve 4 th, 5 th, 2 nd and 3 rd interface, then the rethread two admission valves with in the gas vent of three way exhaust valve discharges into the atmosphere, compressed sample gas washes the admission line when passing through, until its pressure is balanced with atmospheric pressure, waits that the gas sample of analysis is deposited in the ration tube of six-way admission valve, unnecessary sample gas discharges into the atmosphere, realizes the autoloading of gas sample, after the sample loading is finished, opening the six-way sampling valve, and carrying the sample gas stored in the quantitative tube into the chromatogram by carrier gas for sampling analysis;

secondly, the vacuum pump, the two-way exhaust valve and the three-way exhaust valve are used as auxiliary components, the main action mode is that after the sampling needle is inserted into the headspace sample bottle, the vacuum pump, the three-way exhaust valve and the two-way exhaust valve are firstly opened, the vacuum pump vacuumizes the air inlet pipeline, the flow limiting filter and the quantitative tube at the rear end of the two-way intake valve, then the two-way exhaust valve is closed and the two-way intake valve is opened, so that the gas sample in the headspace sample bottle washes the corresponding air inlet pipeline and the quantitative tube under the action of headspace pressure, then the two-way intake valve is closed and the two-way exhaust valve is opened, the quantitative ring is vacuumized by the vacuum pump, then the two-way exhaust valve is closed and the two-way intake valve is opened, the quantitative ring is cleaned by using sample gas, and the process is cleaned for a plurality of times, can improve inlet line's cleanliness, improve and advance kind precision, after washing the completion, keep the two-way admission valve open the two-way air outlet valve open three-way exhaust valve with the vacuum pump is closed, and unnecessary sample gas will pass through in three-way exhaust valve's gas vent discharges into the atmosphere, makes the sample gas of treating the analysis exist with the form of ordinary pressure in the ration ring, accomplish the sample and load the process.

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