Collecting valve, application thereof and supercritical fluid chromatography system

Abstract

The invention belongs to the technical field of valves, and relates to a high-pressure collecting valve suitable for being applied to a liquid chromatography system, application of the high-pressure collecting valve and a supercritical fluid chromatography system. According to the invention, high-pressure collection and automatic collection of samples in the operation process of the supercritical fluid chromatography system can be realized; the valve cavity unit adopts a scheme that equal-length branches are uniformly distributed in a star shape, so that the volume of a channel in the valve body is reduced and rectified, the dead volume of a pipeline can be greatly reduced, cross contamination among different components is reduced or even eliminated, and the sample collection rate and purity of each component are improved; the collecting valve adopts a structure completely different from a ball valve, and is provided with a pressure regulation feedback system and a sealing ring, so that the fault rate and the maintenance cost of the collecting valve can be reduced, and the service life is prolonged. The whole collecting valve adopts a modular design, so that the maintenance cost caused by hardware damage due to long-time high-pressure operation of the supercritical fluid chromatography system can be effectively reduced. And a pressure closed-loop control system is arranged, so that the collection rate and the purity of the sample can be further improved.

Description

Technical Field

[0001] This invention belongs to the field of valve technology, and relates to a collection valve, particularly a high-pressure collection valve suitable for use in liquid chromatography systems and its application, as well as supercritical fluid chromatography systems. Background Technology

[0002] Supercritical fluid chromatography (SCLC) is a chromatographic technique that uses supercritical fluids (most commonly supercritical carbon dioxide) as the mobile phase. It combines some features of gas chromatography (GC) and high-performance liquid chromatography (HPLC), and has advantages such as high separation efficiency, fast analysis speed, high throughput, environmental friendliness, low operating cost, excellent sample recovery, high flexibility, and wide applicability.

[0003] When using collection valves for sample recovery, it is essential to ensure sample purity. However, most liquid chromatography systems use pneumatic ball valves as collection valves, which are not only costly and prone to failure, but also suffer from increased cross-contamination and dead volume due to their vertical layout, leading to lower sample collection rates and purity. Furthermore, ball valves have shorter lifespans and higher characteristic pressures, increasing maintenance costs. Summary of the Invention

[0004] The main objective of this invention is to provide a high-pressure collection valve suitable for use in liquid chromatography systems, which can improve sample collection rate and purity while reducing valve failure rate and maintenance costs, thereby solving the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following solution: On one hand, the present invention provides a collection valve, comprising: The collection valve body includes a sample inlet, a component collection port, and a valve cavity unit opened in the collection valve body. The valve cavity unit includes multiple identical sample collection branches arranged radially. The heads of each sample collection branch converge, and the convergence point is connected to a sample inlet. The tail end of any sample collection branch is provided with the component collection port. The valve core sealing assembly includes multiple sealing valves, and each of the sample collection branches is equipped with a sealing valve. The sealing valve can control the on / off state and pressure of the corresponding sample collection branch.

[0006] In some embodiments, any of the sealing valves includes: A sealing valve body is disposed on the outer periphery of the collection valve body, and a piston chamber is disposed inside the sealing valve body that communicates with the sample collection branch. The piston chamber communicates with the component collection port located on the same sample collection branch. A sealing piston is slidably fitted inside the piston chamber, and the sealing piston is provided with a sealing part that seals with the piston chamber; the sealing piston can connect or block the component collection port and the corresponding sample collection branch under the drive of the collection drive.

[0007] In some embodiments, the front end of the sealing piston is provided with a sealing pin, the sealing part is the conical outer wall of the sealing pin, and the front end of the piston cavity is provided with a sealing conical surface adapted to the conical outer wall.

[0008] In some embodiments, the sealing piston is, from front to back along the axial direction, the sealing pin, the first piston section and the second piston section, wherein the diameter of the second piston section is larger than the diameter of the first piston section and the diameter of the first piston section is not smaller than the tail diameter of the sealing pin. The piston chamber is configured as a stepped shaft cavity that adapts to the contour of the outer wall of the sealed piston; The inner wall of the piston chamber is also provided with a sealing ring for the first piston section to pass through in a sealed manner.

[0009] In some embodiments, the collecting valve further includes a pressure closed-loop control system, the pressure closed-loop control system comprising: A pressure sensing component is connected to the sample inlet; The collection drive is connected to the sealing piston at its output end, and the sealing piston of any of the sealing valves is connected to the collection drive. The control mechanism is communicatively connected to the pressure sensing component and all the collection drives. The control mechanism can automatically adjust the opening degree of the sealing valve by the collection drives according to the pressure of the sample inlet.

[0010] In some embodiments, the collecting drive is a linear telescopic drive located at the tail end of the sealing valve body, and the output end of the linear telescopic drive has a ball socket. The tail end of the sealing piston is provided with a ball head that is adapted to the ball socket, and the sealing piston is rotatably connected to the ball socket through the ball head.

[0011] In some embodiments, the collecting valve further includes a temperature closed-loop control system, the temperature closed-loop control system comprising: A temperature sensing component is disposed on the collecting valve body; A heating module is mounted on the collecting valve body; The control mechanism is communicatively connected to both the temperature sensing component and the heating module. The control mechanism can automatically adjust the heating module according to the temperature of the collecting valve body so that the temperature of the collecting valve body is always not lower than a set threshold.

[0012] In some embodiments, the collecting valve body is circular or polygonal; The valve chamber unit is provided in one set and arranged coaxially with the collecting valve body; or, the valve chamber unit is provided in multiple sets and evenly distributed on the collecting valve body.

[0013] On the other hand, the present invention proposes the application of the collection valve described in any of the above-mentioned claims as a sample collection component in a liquid chromatography system.

[0014] In another aspect, the present invention provides a supercritical fluid chromatography system, including the collection valve described in any one of the above.

[0015] The present invention achieves the following technical effects compared to the prior art: The collection valve proposed in this invention enables high-pressure and automatic sample collection during the operation of a supercritical fluid chromatography system, with the following specific advantages: (1) The valve chamber unit adopts a star-shaped distribution scheme with equal-length branches. On the one hand, it realizes the reduction and rectification of the channel volume in the valve body, which can greatly reduce the dead volume of the pipeline, reduce or even eliminate cross-contamination between different components, and improve the sample collection rate and purity of each component. On the other hand, the star-shaped component collection port design ensures that the distance from the sample inlet to each component collection port is a fixed value. The liquid volume of this distance can be calculated. Combined with the sample flow rate in the pipeline before the sample inlet and the pressure signal detection of the pressure detector, delayed valve closing collection can be realized, which can basically ensure "zero" cross-contamination between different components, and further improve the sample collection rate and sample purity.

[0016] (2) The collection valve adopts a completely different structure from the ball valve and is equipped with a pressure regulation feedback system and sealing ring, which can reduce the failure rate and maintenance cost of the collection valve and extend its service life.

[0017] (3) The collection valve adopts a modular design, which can effectively reduce the maintenance cost caused by hardware damage due to long-term high-pressure operation of the supercritical fluid chromatography system.

[0018] (4) The collection valve can be set with the required collection pressure value by the host computer. The pressure closed-loop control system can intelligently adjust the air source pressure value of the cylinder to make the sealing valve reach the corresponding pressure value. When this component collection port is working, only the air source pressure output of the cylinder corresponding to this component collection port is controlled. The air source pressure value of the cylinder corresponding to the other component collection ports is the maximum value, which is used to ensure the sealing of other sample collection branches. Liquid sealing is achieved through the liquid in the sample collection branch to reduce the chance of contact and mixing of different components, and further improve the sample collection rate and purity.

[0019] (5) The sealing piston tail end and the cylinder are assembled with a quick-release universal mechanism, which can overcome the problem of misalignment caused by the processing and assembly of various parts, thereby reducing the overall cost of the collection valve.

[0020] (6) The collection valve can operate normally under a pressure of 25MPa.

[0021] (7) For low-temperature carbon dioxide in supercritical fluid chromatography systems, this invention, through the deployment of a closed-loop temperature control system, can control the heating module based on the real-time temperature feedback from the temperature sensing component during the process of the sample passing through the outlet of the sealed valve body to a designated component collection port (during which the state of carbon dioxide changes, absorbing heat and causing pipe ice blockage). This process is a closed-loop control process, which improves the stability of the temperature control of the collection valve body through intelligent PID regulation. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall structure of the collection valve disclosed in an embodiment of the present invention; Figure 2 This is a front view of the collection valve disclosed in an embodiment of the present invention (with the top cover of the collection valve body removed). Figure 3 This is a schematic axial cross-sectional view of the collection valve disclosed in an embodiment of the present invention; Figure 4 This is a cross-sectional schematic diagram of the collection valve disclosed in an embodiment of the present invention (with the collection drive state removed). Figure 5 This is a cross-sectional schematic diagram of the sealing valve in the collection valve disclosed in an embodiment of the present invention; Figure 6 This is a cross-sectional view of the connection structure between the tail end of the sealing piston and the collection drive disclosed in an embodiment of the present invention.

[0024] In the figure, the attached reference numeral is: 100 - collection valve; 1-Collection valve body; 11-Sample inlet; 12-Component collection port; 13-Sample collection branch; 2-Sealing valve; 21-Sealing valve body; 22-Piston chamber; 221-Sealing cone surface; 23-Sealing piston; 231-Sealing pin; 232-First piston section; 233-Second piston section; 234-Ball head; 24-Sealing ring; 3-Pressure sensing component; 4-Collection drive; 41-Ball socket; 5-Temperature sensing component; 6-Heating module. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] One of the objectives of this invention is to provide a high-pressure collection valve suitable for use in liquid chromatography systems, which can improve sample collection rate and purity while reducing valve failure rate and maintenance costs, thereby solving the problems existing in the prior art.

[0027] Another object of the present invention is to provide an application of the above-mentioned collection valve.

[0028] Another object of the present invention is to provide a supercritical fluid chromatography system comprising the above-described collection valve.

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Example 1 like Figures 1-3 As shown, this embodiment proposes a collection valve 100 suitable for use in a liquid chromatography system, which includes a collection valve body 1 and a valve core sealing assembly. The collection valve body 1 includes a sample inlet 11, a component collection port 12, and a valve cavity unit within the collection valve body 1. The valve cavity unit includes multiple identical sample collection branches 13 arranged radially. In the valve cavity unit, the beginning ends (i.e., the liquid inlet ends) of each sample collection branch 13 converge and are connected to a sample inlet 11. The end end (i.e., the liquid outlet end) of any sample collection branch 13 is provided with a component collection port 12. The valve core sealing assembly includes multiple sealing valves 2. Any sample collection branch 13... Each of the three components is equipped with a sealing valve 2. The sealing valve 2 can control the opening and closing of the corresponding sample collection branch 13 and the pressure. When the sealing valve 2 blocks the sample collection branch 13, the corresponding component collection port 12 is not connected to the sample inlet 11. At this time, the sample cannot reach the component collection port 12 from the sample inlet 11. When the sealing valve 2 controls the sample collection branch 13 to be open, the corresponding component collection port 12 is connected to the sample inlet 11. The sample can enter from the sample inlet 11 and reach the component collection port 12 through the corresponding sample collection branch 13.

[0031] In practical applications, the sample inlet 11 is connected to the sample inlet line, which is used to connect to the sample source; correspondingly, the component collection port 12 is equipped with a sample discharge line, which is used to connect to the collection device of the corresponding component.

[0032] In some feasible implementations, it is preferable that the structures of each sealing valve 2 and their layout and assembly in the collecting valve 100 are completely identical. Taking one of the sealing valves 2 as an example, such as Figure 4 and Figure 5 As shown, it includes a sealing valve body 21 and a sealing piston 23. The sealing valve body 21 is disposed on the outer periphery of the collection valve body 1 and is sealed to the collection valve body 1 by sealing elements such as sealing rings. The sealing valve body 21 has a piston cavity 22 that communicates with the sample collection branch 13. The piston cavity 22 communicates with the component collection port 12 located on the same sample collection branch 13. The sealing piston 23 is slidably assembled in the piston cavity 22 and has a sealing part that seals with the piston cavity 22. This sealing part is used to control the connection and disconnection between the component collection port 12 and the corresponding sample collection branch 13. In use, the sealing piston 23 receives the collection drive 4. Under the drive of the collection drive 4, the sealing piston 23 can slide relative to the piston cavity 22, thereby changing the position and / or state of the sealing part to realize the connection or disconnection between the component collection port 12 and the corresponding sample collection branch 13 by the sealing valve 2. Each sample collection branch 13 is equipped with a sealing valve 2, which facilitates independent on / off control of each sample collection branch 13. One or more sample collection branches 13 can be connected to collect the same sample as needed.

[0033] Some feasible implementation methods, such as Figure 4 As shown, the front end of the sealing valve body 212 is preferably embedded in the valve body mounting hole on the outer peripheral side wall of the collecting valve body 1. The fixing methods between the two include, but are not limited to, interference fit, threaded connection, or bolt fixing. The valve body mounting hole is preferably coaxial and connected with the corresponding sample collection branch 13, and the inner diameter of the valve body mounting hole is larger than the inner diameter of the sample collection branch 13. This forms a shoulder between the valve body mounting hole and the sample collection branch 13, which facilitates the positioning of the sealing valve body 212 during installation.

[0034] Some feasible implementation methods, such as Figure 4 and Figure 5 As shown, a sealing ring is preferably embedded in the front end face of the sealing valve body 212. After the sealing valve body 212 is installed in the valve body mounting hole on the outer peripheral side wall of the collecting valve body 1, the front end of the sealing valve body 212 is sealed with the end face of the valve body mounting hole (i.e., the aforementioned shoulder) through the sealing ring, so as to avoid sample leakage between the front end face of the sealing valve body 212 and the end face of the valve body mounting hole, and ensure the sealing of the sampling channel.

[0035] Based on the above, it can be seen that a valve chamber unit typically corresponds to one sample inlet 11 and multiple component collection ports 12, the same number as the sample collection branch 13, such as... Figure 1 As shown, preferably, the sample inlet 11 and the component collection port 12 are all arranged on the same end face of the collection valve body 1. In other embodiments, the sample inlet 11 and the component collection port 12 can also be distributed on both end faces of the collection valve body 1 as needed. In the valve chamber unit, the sample collection branches 13 are preferably arranged in a circumferentially evenly distributed manner, and the number of sample collection branches 13 is not limited to three, four, six, seven or eight, etc.

[0036] Some feasible implementation methods, such as Figure 5 As shown, the preferred sealing piston 23 is a pin piston, meaning that a sealing pin 231 is provided at the front end of the sealing piston 23, and the aforementioned sealing part is the conical outer wall of the sealing pin 231. The front cavity wall of the piston chamber 22 is provided with a sealing conical surface 221 that matches the conical outer wall. The sealing conical surface 221 is a frustum cone surface, and its taper is the same as that of the conical outer wall. The sealing piston 23 and the piston chamber 22 are sealed by a conical inclined surface. On the one hand, the conical inclined surface has a good sealing effect and makes it easy to drive the sealing piston 23 away from the sealing conical surface 221, improving the sensitivity of the collection valve to the on / off control of each sample collection branch 13. On the other hand, the conical inclined surface can perform sealing compensation, and the sealing effect will not be affected by the wear of the conical outer wall and / or the sealing conical surface 221, thus extending the service life of the collection valve 100.

[0037] Some feasible implementation methods, such as Figure 5 As shown, the sealing piston 23, from front to back along the axial direction, consists of a sealing pin 231, a first piston section 232, and a second piston section 233. The sealing pin 231, first piston section 232, and second piston section 233 are coaxial. Both the first piston section 232 and the second piston section 233 are preferably cylindrical piston sections. The diameter of the second piston section 233 is larger than the diameter of the first piston section 232, and the diameter of the first piston section 232 is not smaller than the tail diameter of the sealing pin 231. This makes the sealing piston 23 a multi-stage piston structure. Figure 5As shown, the piston cavity 22 is configured as a stepped shaft cavity adapted to the outer wall contour of the sealing piston 23. The first piston section 232 and the second piston section 233 of the sealing piston 23 are both in sealing sliding fit with the corresponding piston cavity section. The inner wall of the section of the piston cavity 22 that fits with the first piston section 232 is also provided with a sealing ring 24 for the first piston section 232 to pass through. The sealing ring 24 is embedded in the inner wall of the piston cavity 22 and is axially limited by the steps before and after the embedding position to prevent the sealing piston 23 from moving the sealing ring 24 during its passage. This sealing ring 24 is preferably a low-temperature and high-pressure resistant sealing ring, such as a perfluoropolymer + S31603 sealing ring (i.e., a sealing ring combining a perfluoroether sealing ring and S31603 stainless steel). It combines the chemical corrosion resistance and high-temperature resistance (-20℃ to 300℃) of perfluoroether with the corrosion resistance and high strength of S31603 stainless steel, ensuring the sealing performance of the sealing valve 2 under high-pressure environments.

[0038] In some feasible implementations, the collection valve 100 also includes a pressure closed-loop control system, such as... Figure 1 As shown, the pressure closed-loop control system includes a pressure sensing component 3, a collection drive 4, and a control mechanism. The pressure sensing component 3 is connected to the sample inlet 11, preferably located on the sample inlet pipeline connected to the sample inlet 11. The output end of the collection drive 4 is connected to the sealing piston 23, and the sealing piston 23 of any sealing valve 2 is connected to the collection drive 4 to achieve independent control of each sealing valve 2. The aforementioned control mechanism is communicatively connected to the pressure sensing component 3 and all collection drives 4. The control mechanism has a built-in mature control program that can automatically adjust the opening degree of the collection drive 4 to control the sealing valve 2 based on the pressure of the sample inlet 11 measured by the pressure sensing component 3 (including the case where the sealing valve 2 is completely closed). The aforementioned pressure closed-loop control system, as the drive mechanism of the collection valve 100, mainly functions to receive instructions from the host computer and start the collection drive 4 to provide the necessary power to the sealing piston 23. The control mechanism can control the extension and retraction of the sealing piston 23, thereby adjusting the gap between the sealing pin 231 and the sealing cone surface 221, realizing automatic pressure control in the sample collection branch 13 to adapt to different process flow rates and improve the level of intelligence.

[0039] The control mechanism is a mature existing technology, such as control circuit board, PLC control mechanism, intelligent PID, etc., which will not be described in detail.

[0040] The pressure sensing component 3 includes, but is not limited to, the use of a pressure sensor.

[0041] In some feasible implementations, the collecting drive 4 is preferably a linear telescopic drive, and the linear telescopic drive can be of various types including but not limited to hydraulic cylinders, pneumatic cylinders, electric cylinders or electric slides.

[0042] In some feasible implementations, the collection drive 4 can be arranged separately from the collection valve body 1, or it can be integrated into the collection valve body 1. Preferably, the collection drive 4 is integrated into the tail end of the sealing valve body 21, which can improve the structural integration and compactness of the collection valve 100. The fixing method between the housing of the collection drive 4 (such as a cylinder) and the tail end of the sealing valve body 21 includes, but is not limited to, bolt fixing, welding fixing, etc.

[0043] In some feasible implementations, the output end of the collecting drive 4 preferably has a ball joint 41, and the tail end of the sealing piston 23 is connected to a ball head 234 adapted to the ball joint 41 via a connecting rod. The sealing piston 23 is rotatably connected to the ball joint 41 via the ball head 234. The collecting drive 4 and the sealing piston 23 are assembled and connected by a universal ball joint structure of ball joint 41 and ball head 234, which can solve the problem of misalignment of various components caused by insufficient machining accuracy.

[0044] The sealing piston 23, connecting rod, and ball head 234 are preferably integrally molded structures, and the materials used include, but are not limited to, ceramics, zirconium oxide, and stainless steel. Correspondingly, the materials of the sealing valve body 21 include, but are not limited to, PEEK (polyetheretherketone), PTFE (polytetrafluoroethylene), and PVDF (polyvinylidene fluoride).

[0045] In some feasible implementations, the collecting valve body 1 is preferably circular or polygonal. When using a polygon, it includes, but is not limited to, rectangles, regular pentagons, and regular hexagons. The collecting valve body 1 may have only one set of valve chamber units, and the valve chamber units are arranged coaxially with the collecting valve body 1, meaning that the intersection point of each branch in the valve chamber unit is coaxial with the center of the collecting valve body 1. Alternatively, multiple sets of valve chamber units may be simultaneously provided on the collecting valve body 1, and these multiple sets of valve chamber units are evenly distributed on the collecting valve body 1. For example, when two sets are provided, they can be arranged symmetrically from left to right; when three or more sets are provided, they can be evenly distributed circumferentially.

[0046] To ensure the operational reliability of the collection valve body 1, valves can be installed at the sample inlet 11 and each component collection port 12. These valves include, but are not limited to, one-way valves.

[0047] The following describes the usage method and operating principle of the above-mentioned collection valve 100, taking the collection valve body 1 as a regular hexagon, a set of valve chamber units coaxially arranged on the collection valve body 1, and the valve chamber unit including six radially distributed sample collection branches 13, and the collection drive 4 using a cylinder as an example.

[0048] like Figures 1-4 As shown, six sample collection branches 13 are arranged radially and evenly. Each sample collection branch 13 is provided with a component collection port 12 at its end. The six component collection ports 12 are evenly distributed in a star shape on the collection valve body 1.

[0049] Flow direction: The sample flows in through the sample inlet 11 at the center of the collection valve body 1, and flows through the internal sample collection branch 13 to the sealing valve body 21. The sealing valve body 21 and the collection valve body 1 are sealed by a sealing ring made of a custom material to prevent sample leakage. Then the sample flows through the gap between the sealing pin 231 and the sealing cone surface 221 and enters the piston chamber 22. The sample is then collected through the corresponding component collection port 12.

[0050] During sample collection, the control mechanism can use intelligent PID to adjust the size of the gas source (the gas source connected to the cylinder) to control the extension and retraction of the sealing piston 23, thereby regulating the gap between the sealing pin 231 and the sealing cone surface 221, realizing automatic pressure control in the sample collection branch 13, so that the sample collection branch 13 is always at the pressure value required for sample collection, ensuring that the sample flows smoothly to the corresponding component collection port 12.

[0051] Working principle: (1) The pressure closed-loop control system realizes the high pressure collection of the collection valve 100 by collecting the pressure value of the pressure sensor at the front end of the pipeline. This pressure value belongs to the process parameter. The user can adjust this parameter through the host computer. This control process belongs to the closed-loop control valve core sealing assembly.

[0052] (2) The gap between the sealing pin 231 and the sealing cone 221 is not constant. The control mechanism of the pressure closed-loop control system reads the parameters of the pressure sensor at the front end of the pipeline to feed back the air source pressure value of the regulating cylinder, thereby adjusting the gap between the sealing pin 231 and the sealing cone 221, so that the collection pressure value is in a dynamic equilibrium state, ensuring that the sample passes smoothly through the piston cavity to reach the corresponding component collection port 12.

[0053] (3) The O-ring 24 on the outside of the first piston section 232 is used to deal with the characteristics of carbon dioxide and can further improve the pressure resistance of the collection valve 100.

[0054] (4) The ball at the tail end of the sealing piston 23 is universally coupled with the ball socket of the collection drive to form a ball joint. This structure enables the sealing piston 23 to adjust a certain angle on its own during the reciprocating motion, so as to adapt to the problem of misalignment of other components during the processing and assembly process, thereby reducing the difficulty of processing and assembly and reducing the overall cost of the collection valve 100.

[0055] (5) During use, the process can be adjusted to allow one component collection port 12 to collect or multiple component collection ports 12 to collect the same sample, depending on the process requirements. Through the host computer program control, only the collection drive corresponding to the component collection port 12 used is started and adjusted, while the collection drive corresponding to the component collection port 12 that has not collected samples is not pressure controlled, and the pipeline is sealed by default at the highest pressure value (i.e., the sealing pin 231 and the sealing cone surface 221 are in close contact and press against each other). This ensures that the sample collected in the sample collection branch 13 is preserved. In this way, during the continuous sample preparation process, the contact opportunity between different components is only at the intersection center of each sample collection branch 13, and the contact area is only the size of the cross-sectional area of ​​the sample collection branch 13, which effectively reduces the risk of cross-contamination between different component samples, thereby improving the sample collection rate and the purity of the collected samples.

[0056] (6) In each valve chamber unit, the length of the six sample collection branches 13 is star-shaped, which ensures that the distance from the sample inlet 11 to each component collection port 12 is fixed and equal. In addition, the pipeline at the front end of the sample inlet 11 is also of fixed volume. Therefore, the channel volume from the detector outlet to each component collection port 12 is fixed and equal. Based on this, the host computer can calculate the flow rate of the current process and combine it with the signal of the pressure sensor to delay and close the sealing valve 2 corresponding to the current component collection port 12. This ensures that all the corresponding components in this fixed volume (the volume from the detector outlet to each component collection port 12) are collected, avoiding sample residue in the sample collection branch 13. This can prevent cross-contamination between samples and improve the purity and efficiency of sample collection.

[0057] In summary, the collection valve proposed in this invention can achieve high-pressure and automatic sample collection during the operation of a supercritical fluid chromatography system, with the following specific benefits: (1) The valve chamber unit adopts a star-shaped distribution scheme with equal-length branches. On the one hand, it realizes the reduction and rectification of the channel volume in the valve body, which can greatly reduce the dead volume of the pipeline, reduce or even eliminate cross-contamination between different components, and improve the sample collection rate and purity of each component. On the other hand, the star-shaped component collection port design ensures that the distance from the sample inlet to each component collection port is a fixed value. The liquid volume of this distance can be calculated. Combined with the sample flow rate in the pipeline before the sample inlet and the pressure signal detection of the pressure detector, delayed valve closing collection can be realized, which can basically ensure "zero" cross-contamination between different components, and further improve the sample collection rate and sample purity.

[0058] (2) The collection valve adopts a completely different structure from the ball valve and is equipped with a pressure regulation feedback system and sealing ring, which can reduce the failure rate and maintenance cost of the collection valve and extend its service life.

[0059] (3) The collection valve adopts a modular design, which can effectively reduce the maintenance cost caused by hardware damage due to long-term high-pressure operation of the supercritical fluid chromatography system.

[0060] (4) The collection valve can be set with the required collection pressure value by the host computer. The pressure closed-loop control system can intelligently adjust the air source pressure value of the cylinder to make the sealing valve 2 reach the corresponding pressure value. When this component collection port 12 is working, only the air source pressure output of the cylinder corresponding to this component collection port 12 is controlled. The air source pressure value of the cylinder corresponding to the other component collection ports 12 is the maximum value, so as to ensure the sealing of other sample collection branches 13. Liquid sealing is achieved through the liquid in the sample collection branch 13, so as to reduce the chance of contact and mixing of different components, and further improve the sample collection rate and purity.

[0061] (5) The sealing piston tail end and the cylinder are assembled with a quick-release universal mechanism, which can overcome the problem of misalignment caused by the processing and assembly of various parts, thereby reducing the overall cost of the collection valve.

[0062] (6) The collection valve can operate normally under a pressure of 25MPa.

[0063] Example 2 like Figure 3 and Figure 4 As shown, this embodiment proposes a collection valve 100 suitable for use in a liquid chromatography system. Based on Embodiment 1, it further includes a temperature closed-loop control system. This temperature closed-loop control system includes a temperature sensing component 5, a heating module 6, and a control mechanism. The temperature sensing component 5 is disposed on the collection valve body 1 and is used to detect the temperature of the collection valve body 1 in real time. The heating module 6 is disposed on the collection valve body 1 and is used to heat the collection valve body 1 to raise or maintain a constant temperature. The control mechanism is communicatively connected to both the temperature sensing component 5 and the heating module 6. The control mechanism can automatically adjust the heating module 6 according to the temperature of the collection valve body 1 measured by the temperature sensing component 5, so that the temperature of the collection valve body 1 is never lower than a set threshold. Figure 3 and Figure 4 As shown, the number of heating modules 6 is preferably the same as the number of sample collection branches 13. In order to ensure uniform heating of the valve body, the heating modules 6 and sample collection branches 13 are preferably staggered along the circumference of the valve body.

[0064] The aforementioned collection valve 100, configured with a heating module 6, constitutes a high-pressure collection valve with a heating function. The heating module 6 includes, but is not limited to, heating rods, Peltiers, water bath heaters, etc. Taking a heating rod as an example, for instance... Figure 3 and Figure 4As shown, multiple heating rods are evenly distributed on the preferred collection valve body 1. The heating module 6 can be divided into automatic mode and manual mode. In automatic mode, the heating is adjusted according to the built-in control program to ensure the normal operation of the collection valve 100; in manual mode, the user can set the temperature value required for the sample in accordance with the process operation.

[0065] The temperature sensing component 5 includes, but is not limited to, thermocouples, and is preferably arranged in the center of the collecting valve body 1, which is beneficial for comprehensive and accurate temperature measurement.

[0066] In this embodiment, the pressure closed-loop control system and the temperature closed-loop control system can operate independently or simultaneously. The control mechanisms of the pressure closed-loop control system and the temperature closed-loop control system can be two separate sets of control mechanisms or a single set of control mechanisms. The control mechanisms utilize mature existing technologies, such as PLC control mechanisms and intelligent PID controllers, which will not be elaborated further.

[0067] Simultaneously, the temperature of the valve body is collected, and the operation of the heating rod is controlled through intelligent PID parameters.

[0068] In use, the control mechanism is externally mounted on the collection valve 100 and is arranged separately from the collection valve 100. The control mechanism can communicate with the collection drive 4, pressure sensing component 3, heating module 6, temperature sensing component 5, etc., via wired or wireless means as needed.

[0069] In traditional supercritical fluid chromatography systems, the presence of carbon dioxide in the mobile phase causes the ball valve (collection valve) to operate at a consistently low temperature due to the heat absorption of carbon dioxide during vaporization after passing through the back pressure valve. This further increases the failure rate of the ball valve (collection valve). In this embodiment, a closed-loop temperature control system is implemented. During the process of the sample passing through the outlet of the sealed valve body 21 to a designated component collection port 12 (during which the state of carbon dioxide changes, absorbing heat and causing ice blockage in the pipeline), the heating module 6 is controlled based on the real-time temperature feedback from the temperature sensor 5. This closed-loop control process uses intelligent PID regulation to improve the stability of temperature control on the collection valve body 1. The temperature threshold set for the collection valve body 1 during this process is also a process parameter, which can be adjusted by the user via a host computer to adapt to the process parameters of different samples.

[0070] For low-temperature carbon dioxide in supercritical fluid chromatography systems, this embodiment preferably uses specially customized sealing rings in the collection valve 100, which have the advantages of low-temperature and high-pressure resistance. For example, sealing ring 24 uses a perfluoroether sealing ring that is resistant to gas explosion. This sealing ring is formed by high-pressure and high-temperature extrusion, which can reduce the gap between materials. After the sealing ring cools and solidifies, nanoscale materials (such as silicon oxide, silicon carbide-graphene nanocomposite materials, etc.) are uniformly sprayed on the surface of the sealing ring to further ensure the tightness of the sealing ring, which can further improve the pressure resistance and explosion-proof effect of the collection valve 100 under low-temperature carbon dioxide fluid conditions.

[0071] Example 3 This embodiment proposes the application of the collection valve 100 in Embodiment 1 or 2 as a sample collection component in a liquid chromatography system, such as as a sample collection valve in a supercritical fluid chromatography system.

[0072] Example 4 This embodiment proposes a supercritical fluid chromatography system, including the collection valve 100 disclosed in Example 1 or 2.

[0073] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0074] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A collecting valve, characterized in that, include: The collection valve body includes a sample inlet, a component collection port, and a valve cavity unit opened in the collection valve body. The valve cavity unit includes multiple identical sample collection branches arranged radially. The heads of each sample collection branch converge, and the convergence point is connected to a sample inlet. The tail end of any sample collection branch is provided with the component collection port. The valve core sealing assembly includes multiple sealing valves, and each of the sample collection branches is equipped with a sealing valve. The sealing valve can control the on / off state and pressure of the corresponding sample collection branch.

2. The collecting valve according to claim 1, characterized in that, Each of the aforementioned sealing valves includes: A sealing valve body is disposed on the outer periphery of the collection valve body, and a piston chamber is disposed inside the sealing valve body that communicates with the sample collection branch. The piston chamber communicates with the component collection port located on the same sample collection branch. A sealing piston is slidably fitted inside the piston chamber, and the sealing piston is provided with a sealing part that seals with the piston chamber; the sealing piston can connect or block the component collection port and the corresponding sample collection branch under the drive of the collection drive.

3. The collecting valve according to claim 2, characterized in that, The front end of the sealing piston is provided with a sealing pin, the sealing part is the conical outer wall of the sealing pin, and the front end of the piston cavity is provided with a sealing conical surface that matches the conical outer wall.

4. The collecting valve according to claim 3, characterized in that, The sealing piston consists of a sealing pin, a first piston section, and a second piston section along the axial direction from front to back. The diameter of the second piston section is larger than the diameter of the first piston section, and the diameter of the first piston section is not smaller than the tail diameter of the sealing pin. The piston chamber is configured as a stepped shaft cavity that adapts to the contour of the outer wall of the sealed piston; The inner wall of the piston chamber is also provided with a sealing ring for the first piston section to pass through in a sealed manner.

5. The collecting valve according to any one of claims 2 to 4, characterized in that, It also includes a pressure closed-loop control system, which comprises: A pressure sensing component is connected to the sample inlet; The collection drive is connected to the sealing piston at its output end, and the sealing piston of any of the sealing valves is connected to the collection drive. The control mechanism is communicatively connected to the pressure sensing component and all the collection drives. The control mechanism can automatically adjust the opening degree of the sealing valve by the collection drives according to the pressure of the sample inlet.

6. The collecting valve according to claim 5, characterized in that, The collecting drive is a linear telescopic drive located at the tail end of the sealing valve body, and the output end of the linear telescopic drive has a ball socket. The tail end of the sealing piston is provided with a ball head that is adapted to the ball socket, and the sealing piston is rotatably connected to the ball socket through the ball head.

7. The collecting valve according to any one of claims 1 to 4, characterized in that, It also includes a temperature closed-loop control system, which comprises: A temperature sensing component is disposed on the collecting valve body; A heating module is mounted on the collecting valve body; The control mechanism is communicatively connected to both the temperature sensing component and the heating module. The control mechanism can automatically adjust the heating module according to the temperature of the collecting valve body so that the temperature of the collecting valve body is always not lower than a set threshold.

8. The collecting valve according to any one of claims 1 to 4, characterized in that, The collecting valve body is circular or polygonal; The valve chamber unit is provided in one set and arranged coaxially with the collecting valve body; or, the valve chamber unit is provided in multiple sets and evenly distributed on the collecting valve body.

9. The application of the collection valve according to any one of claims 1 to 8 as a sample collection component in a liquid chromatography system.

10. A supercritical fluid chromatography system, characterized in that, Includes the collection valve as described in any one of claims 1 to 8.

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