Three-position seven-way valve, chromatographic analysis system and working method of chromatographic analysis system

Abstract

The invention provides a three-position seven-way valve, a chromatographic analysis system and a working method of the chromatographic analysis system, and relates to the technical field of liquid chromatography. The three-position seven-way valve comprises a rotor, a valve head and a valve body, the valve head is provided with a pressure relief opening and six functional ports, the rotor is provided with a first flow guide groove, a second flow guide groove, a third flow guide groove and a pressure relief groove, and communication of different flow paths is achieved through rotation of the rotor. During mode switching, high-pressure fluid in the quantitative loop is actively guided to the pressure relief opening through the pressure relief groove to release pressure, uncontrolled expansion towards a sample injection needle or a pump end is avoided, backflushing interference is effectively reduced, reverse pushing or disturbance of a sample is prevented, and the accuracy and repeatability of the sample suction volume in the sample loading stage are guaranteed. The integrated pressure relief design does not need an external device, a flow path is simplified, and the integration level and reliability of the system are improved. The device is suitable for high-precision suction type sample injection, and the sample injection stability and the chromatographic analysis reproducibility are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of liquid chromatography technology, and in particular to a three-position seven-way valve, a chromatographic analysis system and its working method. Background Technology

[0002] In liquid chromatography analysis, the stability and precision of the sample introduction system directly affect the accuracy and repeatability of quantitative results. In modern high-performance liquid chromatography (HPLC) or ultra-high-performance liquid chromatography (UHPLC) systems, aspiration autosamplers are commonly used to achieve precise introduction of high-throughput, minute-volume samples. These autosamplers typically consist of a six-way valve, a quantitative loop, an injection needle, a syringe pump, and related flow paths. The loading and injection processes of the sample are controlled by switching the valve's operating state.

[0003] In a typical two-position six-way valve, there are six ports and a rotatable rotor for switching between two operating modes: one is injection mode, in which the high-pressure infusion pump is connected to the column flow path through a metering loop, allowing the sample to enter the separation system with the mobile phase; the other is loading mode, in which the metering loop is disconnected from the main mobile phase path and connected to the sample loop, so that the injection pump can draw the sample solution from the sample vial to complete the sample loading operation.

[0004] However, in practical applications, it has been found that when the valve switches from the injection mode to the loading mode under high pressure, the metering loop and its connected flow path, which were originally in a high-pressure environment, suddenly lose their restraint, and the internal compressed liquid expands and releases energy into the low-pressure area. Since traditional six-way valves only have two fixed working positions and lack a dedicated pressure relief channel, the high-pressure fluid in the metering loop is released simultaneously in multiple directions at the moment of switching, primarily flowing towards the injection needle end and the syringe pump end. Because the injection needle end is exposed to the atmospheric environment (normal pressure), its terminal pressure is much lower than that of the pump end, and the overall flow resistance of this branch is relatively low, thus becoming the main pressure release path. This uncontrolled pressure release behavior brings a series of technical problems: First, the rapid rush of high-pressure fluid towards the injection needle end causes partial discharge or disturbance of the sample solution that has been filled into the needle tube, sampling tubing, and buffer chamber through the rinsing step, resulting in the regeneration of local cavities or bubbles; second, in the subsequent sample loading stage, although the syringe pump draws liquid according to the preset volume, the actual effective sample volume drawn in is reduced or the composition is uneven due to the disturbance at the front end, ultimately leading to a deviation in the injection volume. This phenomenon is particularly pronounced when injecting micro-volume samples (such as a few microliters or even nanoliters), which seriously affects the precision and accuracy of the analytical data. Summary of the Invention

[0005] The purpose of this invention is to provide a three-position seven-way valve, a chromatographic analysis system and its working method, so as to alleviate the technical problem that the high-pressure liquid in the quantitative loop is abnormally released to the needle end due to the high-pressure flow path switching during the aspiration injection process, thereby affecting the accuracy of sample aspiration.

[0006] In a first aspect, the three-position seven-way valve provided by the present invention includes a rotor, a valve head and a valve body, wherein the valve head is connected to the valve body, the rotor is rotatably mounted in the valve body, and the axial end face of the rotor is tightly fitted with the valve head through surface contact. The valve head is provided with a pressure relief port and six functional ports, which are spaced apart. The rotor is provided with a first guide groove, a second guide groove, a third guide groove, and a pressure relief groove, and the first guide groove, the second guide groove, the third guide groove, and the pressure relief groove are arranged at intervals; The first flow guide groove, the second flow guide groove, and the third flow guide groove are respectively used to connect two of the functional ports, and the pressure relief groove is used to connect the pressure relief port to any of the functional ports.

[0007] In conjunction with the first aspect, the present invention provides a first possible implementation of the first aspect, wherein the six said functional ports are arranged at circumferential intervals along the valve head; The first guide groove, the second guide groove and the third guide groove extend along the circumference of the rotor.

[0008] In conjunction with the first possible implementation of the first aspect, the present invention provides a second possible implementation of the first aspect, wherein the central angle of the first guide groove around the axis of the rotor is 80° to 100°, the central angle of the second guide groove around the axis of the rotor is 55° to 65°, and the central angle of the third guide groove around the axis of the rotor is 55° to 65°.

[0009] In conjunction with the first possible implementation of the first aspect, the present invention provides a third possible implementation of the first aspect, wherein the pressure relief groove extends radially along the rotor between the first guide groove and the second guide groove.

[0010] In conjunction with the first aspect, the present invention provides a fourth possible implementation of the first aspect, wherein the pressure relief port is coaxially arranged with the valve head, and the six functional ports are spaced apart around the pressure relief port.

[0011] In a second aspect, the chromatographic analysis system provided by the present invention includes: a chromatographic column, a high-pressure pump, a syringe, a needle, a waste liquid tube, a buffer tube, a quantitative loop, and a three-position seven-way valve as described in the first aspect; The six functional ports include a quantitative loop inlet, a mobile phase inlet, a chromatographic column port, a quantitative loop outlet, a syringe port, and an injection needle port, which are distributed sequentially and at intervals along the circumference of the valve head. The quantitative loop inlet is fluidly connected to the quantitative loop outlet via the quantitative loop; the mobile phase inlet is fluidly connected to the high-pressure pump; the column inlet is fluidly connected to the column; the syringe port is fluidly connected to the syringe; and the injection needle port is fluidly connected to the syringe via the buffer tube. The pressure relief port is in fluid communication with the waste liquid pipe.

[0012] Thirdly, the chromatographic analysis system provided by the present invention adopts the chromatographic analysis system described in the second aspect and has an injection mode, a depressurization mode and a sample loading mode. The working method of the chromatographic analysis system includes: switching between three modes—the injection mode, the depressurization mode, and the sample loading mode—by driving the rotor to rotate; The rotor station corresponding to the depressurization mode is located between the rotor station corresponding to the sample injection mode and the rotor station corresponding to the sample loading mode.

[0013] In the injection mode, the quantitative loop inlet and the mobile phase inlet are connected via the first guide channel, the column port and the quantitative loop outlet are connected via the second guide channel, and the needle port and the injection needle port are connected via the third guide channel.

[0014] In the pressure relief mode, the quantitative loop inlet is connected to the pressure relief port via the pressure relief groove, the mobile phase inlet is connected to the chromatographic column port via the first flow guide groove, and the quantitative loop outlet, the needle port, and the injection needle port are disconnected from each other.

[0015] In the sample loading mode, the quantitative loop inlet is connected to the injection needle port via the third guide channel, the mobile phase inlet is connected to the chromatographic column port via the first guide channel, and the quantitative loop outlet is connected to the needle port via the second guide channel.

[0016] The embodiments of this invention bring the following beneficial effects: The liquid chromatography injection system using this three-position seven-way valve can effectively solve the technical problem of inaccurate sample pre-absorption volume caused by sudden pressure relief in the high-pressure flow path during mode switching of traditional two-position six-way valves. By adding an independent pressure relief port on the valve head and setting a matching pressure relief groove in the rotor, the high-pressure fluid in the quantitative loop can be actively guided to the pressure relief port to release pressure through the pressure relief groove during the valve switching from injection mode to sample loading mode, instead of expanding freely towards the injection needle tip or the syringe pump tip without control. This design significantly reduces the backflow interference of high-pressure release on the needle tube and the sample rinsing flow path at the front end, and avoids the backflow or disturbance of the already filled sample, thereby ensuring the accuracy and repeatability of the sample aspiration volume in the subsequent sample loading stage.

[0017] Furthermore, this three-position seven-way valve integrates pressure relief functionality within the valve body, achieving controllable pressure release path and structural integration. It eliminates the need for external pressure relief devices or complex auxiliary pipelines, simplifying the overall flow path design, improving system integration and reliability, and enabling high-precision sample injection without increasing operational complexity. It is particularly suitable for aspiration-type sample injection scenarios where sample volume stability is extremely important, helping to improve the precision and reproducibility of liquid chromatography analysis results. It possesses outstanding substantive features and significant technological advancements.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 A schematic diagram of the chromatographic analysis system provided in the embodiment of the present invention in the sample injection mode; Figure 2 A schematic diagram of the chromatographic analysis system provided in the embodiment of the present invention in pressure relief mode; Figure 3 A schematic diagram of the chromatographic analysis system provided in the embodiment of the present invention in sample loading mode; Figure 4 A schematic diagram of the valve head of a three-position seven-way valve provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the rotor of a three-position seven-way valve provided in an embodiment of the present invention.

[0021] Icons: 1-Rotor; 1a-First guide channel; 1b-Second guide channel; 1c-Third guide channel; 1d-Pressure relief channel; 2-Valve head; 2a-Quantitative loop inlet; 2b-Mobile phase inlet; 2c-Column port; 2d-Quantitative loop outlet; 2e-Needle port; 2f-Injection needle port; 2g-Pressure relief port; 3-Column; 4-High-pressure pump; 5-Injector; 6-Needle; 7-Waste liquid tube; 8-Buffer tube; 9-Quantitative loop. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used only to describe differences in name and should not be construed as indicating or implying relative importance. Physical quantities in formulas, unless otherwise specified, should be understood as basic quantities in the International System of Units (SI), or derived quantities derived from basic quantities through mathematical operations such as multiplication, division, differentiation, or integration.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5As shown, this embodiment of the invention provides a three-position seven-way valve, including a rotor 1, a valve head 2, and a valve body. The valve head 2 is fixedly connected to one end of the valve body, forming a sealed chamber. The rotor 1 is rotatably mounted in this sealed chamber, and its axial end face achieves a high-precision sealing fit with the inner surface of the valve head 2 through surface contact, ensuring that the fluid does not cross-flow or leak. The valve head 2 has seven ports: one pressure relief port 2g and six functional ports (namely, quantitative loop inlet 2a, mobile phase inlet 2b, chromatographic column port 2c, quantitative loop outlet 2d, needle port 2e, and injection needle port 2f). All ports penetrate the valve head 2 and communicate with its internal flow channels.

[0026] In this embodiment, four guide grooves are machined on the end face of the rotor 1: a first guide groove 1a, a second guide groove 1b, a third guide groove 1c, and a pressure relief groove 1d. The four grooves are arranged at intervals along the circumference of the rotor, and are independent of each other and not connected to each other. When the rotor 1 rotates to different angular positions, each guide groove connects with a different port, thereby establishing a corresponding fluid passage.

[0027] Among them: the first guide channel 1a is used to connect two functional ports at a specific work station; the second guide channel 1b and the third guide channel 1c are similarly used to realize the connection between other ports; the pressure relief channel 1d is specifically used to connect the pressure relief port 2g with a certain functional port (usually the quantitative loop inlet 2a) at a certain intermediate transition position to realize the high pressure release function.

[0028] This embodiment achieves pilot-operated pressure relief during sample injection by adding a pressure relief port to the traditional six-way valve and redesigning the channel layout on the rotor, effectively solving the problem of inaccurate sample aspiration caused by sudden pressure changes.

[0029] Based on the above implementation method, this embodiment further specifies that: the six functional ports are evenly distributed along the circumference of the valve head 2 in a ring arrangement, and the central area is reserved for setting up the pressure relief port 2g. This layout is beneficial for optimizing the flow channel length, reducing dead volume, and facilitating connection with external pipelines.

[0030] Meanwhile, the first guide groove 1a, the second guide groove 1b, and the third guide groove 1c are all arc-shaped grooves extending along the circumference of the rotor 1. When the rotor rotates, these arc-shaped grooves sweep across the corresponding functional ports in sequence, maintaining a connected state within a predetermined angle range. Since the alignment of the grooves and ports depends on precise angle control, the rotor is manufactured using CNC precision machining technology to ensure that the positional tolerance of the groove start angle and end angle is less than ±0.5°, ensuring the repeatability and reliability of the switching action. This structural design allows the required functional ports to be stably and accurately connected in different operating modes, avoiding increased flow resistance or pressure fluctuations caused by misalignment or partial connection.

[0031] In this embodiment, the central angle corresponding to the guide grooves is specifically defined as follows: the central angle of the first guide groove 1a around the rotor axis is 80° to 100°, for example: 80°, 85°, 90°, 95° or 100°, preferably 90°; the central angle of the second guide groove 1b is 55° to 65°, for example: 55°, 58°, 60°, 62° or 65°, preferably 60°; the central angle of the third guide groove 1c is also 55° to 65°, for example: 55°, 58°, 60°, 62° or 65°, preferably 60°.

[0032] The above angle setting is based on the following considerations: The first guide channel 1a serves as the main mobile phase pathway in injection mode (connecting the mobile phase inlet 2b and the quantitative loop inlet 2a). Simultaneously, it needs to maintain continuous communication between the mobile phase inlet 2b and the column inlet 2c in depressurization mode to prevent back pressure interruption during high-pressure pump 4 switching, which could cause pump blockage. Therefore, a wider 90° channel is used to extend its connectivity window. The second guide channel 1b and the third guide channel 1c are mainly used to complete the connection between the quantitative loop outlet side and the column, as well as the injection system. A width of approximately 60° is sufficient to meet the synchronous connectivity time required for normal switching.

[0033] Experimental verification shows that this angle configuration can ensure sufficient connectivity time while leaving enough non-connectivity intervals for isolation and switching during the pressure relief phase, representing the best balance between performance and structural compactness.

[0034] Furthermore, the pressure relief groove 1d extends radially along the rotor 1, extending from the outer edge to the center into the region between the first guide groove 1a and the second guide groove 1b, but does not communicate with any other guide groove.

[0035] Specifically, the pressure relief groove 1d is a straight shallow groove or through hole, one end of which is exposed on the rotor end face and can be aligned with the pressure relief port 2g when the rotor rotates to the pressure relief mode, forming a temporary connection path; the other end is adjacent to the functional area near the first guide groove 1a, so as to be briefly connected with the quantitative ring inlet 2a under the appropriate phase.

[0036] When the three-position seven-way valve switches from sample injection mode to sample loading mode, the rotor passes through an intermediate angle position (i.e., pressure relief mode). At this time, the pressure relief groove 1d simultaneously connects the metering loop inlet 2a and the pressure relief port 2g, allowing the high-pressure liquid in the metering loop to be quickly discharged to the waste liquid collection device. Since this pressure relief process occurs before the injection needle tip is connected, interference from high-pressure backflow to the sample system is completely avoided. This radial groove structure is simple, easy to manufacture, and can precisely control the pressure relief timing, exhibiting high mechanical reliability and repeatability.

[0037] In this embodiment, the pressure relief port 2g is located at the geometric center of the valve head 2, and the pressure relief port 2g is coaxial with the rotor 1. The six functional ports are arranged in a circular array around the pressure relief port 2g, with an included angle of approximately 60° between adjacent ports.

[0038] This centrally symmetrical layout offers the following advantages: 1. It facilitates the installation of a vertically penetrating pressure relief channel in the rotor's central region, reducing manufacturing difficulty; 2. The central pressure relief port can be flexibly matched with radial grooves or multi-segment combination grooves on the rotor, enhancing design freedom; 3. Its compact structure helps reduce the overall valve size, making it suitable for space-constrained autosampler modules; 4. It exhibits excellent hydrodynamic performance, reducing eddies and stagnant zones, and lowering the risk of cross-contamination. Furthermore, the 2g pressure relief port can be connected to a waste liquid bottle or other low-pressure collection container via a short pipe. If necessary, a one-way valve or microporous filter membrane can be added to prevent backflow of outside air into the system.

[0039] like Figure 1 , Figure 2 and Figure 3 As shown, this embodiment provides a chromatographic analysis system, including a chromatographic column 3, a high-pressure pump 4, a syringe 5, a needle tube 6, a waste liquid tube 7, a buffer tube 8, a quantitative loop 9, and a three-position seven-way valve as described in any of the preceding embodiments.

[0040] The specific connections are as follows: the quantitative loop inlet 2a is connected to the quantitative loop outlet 2d via the quantitative loop 9, forming a sample containment loop; the mobile phase inlet 2b is connected to the outlet of the high-pressure pump 4 to introduce the mobile phase; the column port 2c is connected to the inlet end of the column 3; the needle port 2e is connected to the needle 6 to guide the sample in or flush away residue; the injection needle port 2f is connected to the syringe 5, with a buffer tube 8 in between to reduce pressure shock; and the pressure relief port 2g is connected to the waste liquid tube 7 to introduce the released high-pressure mobile phase into the waste liquid system.

[0041] The entire system is integrated into a high-performance liquid chromatography (HPLC) or ultra-high-performance liquid chromatography (UHPLC) platform, making it particularly suitable for high-precision quantitative analysis in micro-volume injection scenarios (1–100 μL). By using the aforementioned three-position seven-way valve, the system can automatically complete the operation process of depressurization followed by sampling without the need for additional electronic control components, significantly improving injection consistency and data reproducibility.

[0042] This embodiment provides a method for operating a chromatographic analysis system, which adopts the system structure described in the above embodiments and includes three operating modes: injection mode, depressurization mode, and sample loading mode.

[0043] This method uses a drive motor to rotate rotor 1, sequentially switching it to three preset positions, each corresponding to a different operating mode. The rotor position in the depressurization mode is located in the transition angle range between the sample introduction and sample loading modes, serving as a necessary stage in the switching process. The control system issues commands according to a pre-set program, activating stepper motors or servo motors to drive the rotor to rotate sequentially. Since the transitions between modes are entirely determined by the mechanical structure, fully automated operation can be achieved without complex timing programming or external sensor feedback.

[0044] Experiments have shown that each switching process takes about 50–100 milliseconds, and the depressurization time lasts about 20–40 milliseconds, which is sufficient to reduce the pressure in the quantitative loop to the ambient level, ensuring that subsequent sampling actions are stable and reliable.

[0045] See Figure 1 In injection mode, rotor 1 rotates to its initial position (injection position). At this time: the first guide channel 1a spans the mobile phase inlet 2b and the quantitative loop inlet 2a, allowing the mobile phase output from the high-pressure pump 4 to flow into the quantitative loop 9; the second guide channel 1b connects the column port 2c and the quantitative loop outlet 2d, pushing the loaded sample into the column 3 for separation; the third guide channel 1c connects the needle port 2e and the injection needle port 2f, keeping the needle 6 and syringe 5 in communication, facilitating cleaning or preparation for the next cycle. In this mode, the pressure relief port 2g is sealed by the rotor's solid surface and does not participate in the flow path. The system is in a fully enclosed high-pressure state, suitable for long-term continuous injection analysis. This mode continues until the current sample is separated, at which point the system triggers a switching command to enter the next stage.

[0046] When rotor 1 begins to rotate from sample introduction mode to sample loading mode, it first enters the pressure relief mode (transition position), see [link to relevant documentation]. Figure 2 At this point: the connection between the mobile phase inlet 2b and the metering loop inlet 2a is severed; the metering loop inlet 2a is briefly connected to the pressure relief port 2g via the pressure relief groove 1d, allowing the high-pressure liquid inside the metering loop to be rapidly discharged into the waste liquid pipe 7; simultaneously, the first guide groove 1a maintains the connection between the mobile phase inlet 2b and the column port 2c, allowing the main mobile phase to continue flowing to the column 3, maintaining stable system back pressure, and preventing pump stoppage or bubble generation; the metering loop outlet 2d, the needle port 2e, and the injection needle port 2f are disconnected from each other, forming electrical and fluid isolation to prevent pressure disturbances from propagating to the injection system. This pressure relief process lasts approximately 20–40 milliseconds. After the pressure is basically released, the rotor continues to rotate and enters the sample loading mode. The key to this mode is that it achieves dual protection of high-pressure directional venting and continuous flow of the main mobile phase, protecting precision components without affecting system stability.

[0047] See Figure 3In sample loading mode, rotor 1 reaches its final position (sample loading position). At this point: the third guide channel 1c connects the quantitative loop inlet 2a and the injection needle port 2f, establishing a low-pressure sample aspiration path; the second guide channel 1b connects the quantitative loop outlet 2d and the needle port 2e, forming a drainage path; the first guide channel 1a continues to maintain the connection between the mobile phase inlet 2b and the column port 2c, maintaining the pre-column pressure; the pressure relief port 2g is sealed again by the rotor body, ceasing operation. Subsequently, syringe 5 initiates negative pressure aspiration, drawing the target sample from the sample vial through needle 6 and buffer tube 8, flowing through the quantitative loop 9 until the entire volume is filled. Since there is no residual pressure in the quantitative loop 9 at this point, the sample can be completely filled without virtual volume error. After sample loading is completed, the system can switch back to injection mode to begin a new analysis cycle. In this mode, the entire sample aspiration process is conducted in a low-pressure, undisturbed environment, greatly improving the accuracy and repeatability of micro-injection.

[0048] In summary, this invention innovatively introduces a seventh port and a dedicated pressure relief groove 1d structure to construct a novel three-position seven-way valve, successfully achieving logical control of first relieving pressure and then connecting. This solution not only fundamentally solves the pressure backflow problem existing in traditional suction-type autosamplers, but also has significant advantages such as simple structure, high reliability, strong compatibility, and controllable cost.

[0049] The proposed alternatives (such as eccentric pressure relief port 2g, axial piston valve, and electrically controlled pilot valve) can also achieve the same technical effect, demonstrating the wide application adaptability and expansion potential of this invention.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A three-position seven-way valve, characterized in that, It includes a rotor (1), a valve head (2) and a valve body. The valve head (2) is connected to the valve body. The rotor (1) is rotatably installed in the valve body, and the axial end face of the rotor (1) is tightly fitted with the valve head (2) through surface contact. The valve head (2) is provided with a pressure relief port (2g) and six functional ports, and the pressure relief port (2g) and the six functional ports are arranged at intervals; The rotor (1) is provided with a first guide groove (1a), a second guide groove (1b), a third guide groove (1c) and a pressure relief groove (1d), and the first guide groove (1a), the second guide groove (1b), the third guide groove (1c) and the pressure relief groove (1d) are arranged at intervals; The first flow guide groove (1a), the second flow guide groove (1b) and the third flow guide groove (1c) are respectively used to connect two of the functional ports, and the pressure relief groove (1d) is used to connect the pressure relief port (2g) to any of the functional ports.

2. The three-position seven-way valve according to claim 1, characterized in that, The six functional ports are arranged at circumferential intervals along the valve head (2); The first guide groove (1a), the second guide groove (1b) and the third guide groove (1c) extend along the circumference of the rotor (1).

3. The three-position seven-way valve according to claim 2, characterized in that, The central angle of the first guide groove (1a) around the axis of the rotor (1) is 80° to 100°, the central angle of the second guide groove (1b) around the axis of the rotor (1) is 55° to 65°, and the central angle of the third guide groove (1c) around the axis of the rotor (1) is 55° to 65°.

4. The three-position seven-way valve according to claim 2, characterized in that, The pressure relief groove (1d) extends radially along the rotor (1) between the first guide groove (1a) and the second guide groove (1b).

5. The three-position seven-way valve according to claim 1, characterized in that, The pressure relief port (2g) is coaxially arranged with the valve head (2), and the six functional ports are spaced apart around the pressure relief port (2g).

6. A chromatographic analysis system, characterized in that, include: The chromatographic column (3), high-pressure pump (4), syringe (5), needle tube (6), waste liquid tube (7), buffer tube (8), metering loop (9), and the three-position seven-way valve as described in any one of claims 1 to 5; The six functional ports include a quantitative loop inlet (2a), a mobile phase inlet (2b), a chromatographic column port (2c), a quantitative loop outlet (2d), a needle port (2e), and an injection needle port (2f), which are distributed sequentially and at intervals along the circumference of the valve head (2). The quantitative loop inlet (2a) is fluidly connected to the quantitative loop outlet (2d) via the quantitative loop (9), the mobile phase inlet (2b) is fluidly connected to the high-pressure pump (4), the column port (2c) is fluidly connected to the column (3), the needle port (2e) is fluidly connected to the needle (6), and the injection needle port (2f) is fluidly connected to the syringe (5) via the buffer tube (8). The pressure relief port (2g) is in fluid communication with the waste liquid pipe (7).

7. A method for operating a chromatographic analysis system, characterized in that, The chromatographic analysis system operates using the chromatographic analysis system described in claim 6, and has an injection mode, a depressurization mode, and a sample loading mode. The working method of the chromatographic analysis system includes: switching between three modes—the injection mode, the depressurization mode, and the sample loading mode—by driving the rotor (1) to rotate; The rotor station corresponding to the depressurization mode is located between the rotor station corresponding to the sample injection mode and the rotor station corresponding to the sample loading mode.

8. The operating method of the chromatographic analysis system according to claim 7, characterized in that, In the injection mode, the quantitative loop inlet (2a) and the mobile phase inlet (2b) are connected via the first guide channel (1a), the column port (2c) and the quantitative loop outlet (2d) are connected via the second guide channel (1b), and the needle port (2e) and the injection needle port (2f) are connected via the third guide channel (1c).

9. The operating method of the chromatographic analysis system according to claim 7, characterized in that, In the pressure relief mode, the quantitative loop inlet (2a) and the pressure relief port (2g) are connected through the pressure relief groove (1d), the mobile phase inlet (2b) and the chromatographic column port (2c) are connected through the first guide groove (1a), and the quantitative loop outlet (2d), the needle port (2e) and the injection needle port (2f) are disconnected from each other.

10. The method of operating the chromatographic analysis system according to claim 7, characterized in that, In the sample loading mode, the quantitative loop inlet (2a) is connected to the injection needle port (2f) via the third guide channel (1c), the mobile phase inlet (2b) is connected to the chromatographic column port (2c) via the first guide channel (1a), and the quantitative loop outlet (2d) is connected to the needle port (2e) via the second guide channel (1b).

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