Passive pressure-compensated gradient proportional valve

Abstract

The application provides a passive pressure correction gradient proportional valve. A plurality of solvent inlet pipelines, the inlet of each solvent inlet pipeline is connected with a solvent channel, and the outlet of each solvent inlet pipeline is connected with an inlet channel of a passive flow corrector; the passive flow corrector comprises a plurality of inlet channels, outlet channels and chambers, each inlet channel is connected with a chamber, the surface between the adjacent chambers is a common surface, coupling change devices are arranged on the common surface, each outlet channel is connected with the inlet of a solenoid valve, and the outlet of the solenoid valve is connected with the inlet of a solvent outlet pipeline. The application can effectively reduce the influence of the diaphragm pump effect, correct the pressure fluctuation and improve the proportioning accuracy of the solvent composition arranged in the gradient proportional valve when the solenoid valve of the gradient proportional valve is alternately opened and closed.

Description

Technical Field

[0001] This invention relates to the field of proportional valve technology, and more particularly to a passive pressure correction gradient proportional valve. Background Technology

[0002] Low-pressure mixed liquid chromatography (LC) systems, also known as quaternary systems, rely heavily on gradient proportioning valves (GPVs). These valves are crucial components, widely used in analytical and preparative separation applications requiring precise proportioning of multiple solvents. Their primary function is to set the desired solvent composition within the system and precisely adjust the mass ratios of different solvents to ensure the mixed solvent composition meets analytical or preparative requirements. The separation efficiency and detection accuracy of a liquid chromatography system largely depend on the accuracy and stability of the solvent ratios provided by the gradient proportioning valve.

[0003] Existing typical gradient proportional valves usually include multiple solenoid valves; for quaternary systems, four solenoid valves are generally required. Their working principle is based on the periodic action of the system pump during liquid aspiration, controlling the opening and closing of the solenoid valves at precise timing. Specifically, within one aspiration cycle, different solenoid valves are controlled to open sequentially, but only one solenoid valve is open at any given time, while the others remain closed; when a new solenoid valve opens, the previously opened solenoid valve must immediately close. By precisely controlling the opening duration of different solenoid valves, the amount of solvent drawn in can be adjusted, thereby achieving the proportional mixing of the solvent composition.

[0004] However, in practical applications, the solenoid valve of the aforementioned gradient proportional valve generates a diaphragm pump effect during high-speed opening and closing. This effect causes instantaneous pressure fluctuations in the solvent lines, specifically manifested as an abnormal increase in pressure in the closed solvent lines and a sudden decrease in pressure in the open solvent lines. This pressure instability directly interferes with the precise control of the flow rates of each solvent, thereby reducing the accuracy of the desired ratio between solvent components. The impact of pressure fluctuations is particularly significant when there are small ratios between solvent components, easily leading to a significant deviation of the final mixed solvent ratio from the set value, affecting the reproducibility and accuracy of liquid chromatography analysis. Summary of the Invention

[0005] To address the technical problem of pressure fluctuations caused by the diaphragm pump effect resulting from the solenoid valve switching in existing gradient proportional valves, particularly the decrease in solvent proportioning accuracy during small-scale registration, a passive pressure correction gradient proportional valve is provided. This invention primarily utilizes a pair of coupled chambers separated by a movable isolator in the solvent flow path. This allows pressure fluctuations in different solvent lines to be passively balanced through the coupled change in chamber volume during solenoid valve switching, thereby eliminating the pressure pulsation caused by the diaphragm pump effect and significantly improving solvent proportioning accuracy, especially during small-scale registration.

[0006] The technical means employed in this invention are as follows:

[0007] A passive pressure-corrected gradient proportional valve, comprising: Several solvent inlet pipes, each solvent inlet pipe has its inlet connected to a solvent channel, and each solvent inlet pipe has its outlet connected to an inlet channel of a passive flow corrector. The passive flow corrector includes several inlet channels, outlet channels, and chambers. Each inlet channel is connected to a chamber, and the surfaces between adjacent chambers are common surfaces. A coupling change device is provided on the common surface. Each outlet channel is connected to the inlet of a solenoid valve, and the outlet of the solenoid valve is connected to the inlet of the solvent outlet pipeline.

[0008] Furthermore, the coupling change device is a piston, one side of which is in contact with the solvent in one chamber, and the other side of which is in contact with the solvent in another chamber.

[0009] Furthermore, the coupling change device is a partition, which is an elastic partition. One side of the partition is in contact with the solvent in one chamber, and the other side of the partition is in contact with the solvent in another chamber.

[0010] Furthermore, when the volume of the chamber on one side of the coupling change device changes, the coupling change device will be displaced or deformed due to the change in pressure on one side, causing the volume of the chamber on the other side to change.

[0011] Furthermore, the inner wall of the chamber is a smooth inner wall, and the connection between the chamber and the inlet channel and the outlet channel is a rounded transition.

[0012] Furthermore, a sealing ring is fitted on the outer side of the piston.

[0013] Furthermore, the material of the partition is one of FFKM, PTFE or PFA.

[0014] Furthermore, a solvent extension pipeline is provided between the solenoid valve and the solvent outlet pipeline, and the outlet of each solenoid valve is connected to the inlet of a solvent extension pipeline, and the outlets of all solvent extension pipelines are connected to the inlet of the solvent outlet pipeline.

[0015] Furthermore, a solvent premixer is provided between the solvent extension pipeline and the solvent outlet pipeline. The outlet of the solvent extension pipeline is connected to the inlet pipeline of the solvent premixer, and the outlet pipeline of the solvent premixer is connected to the inlet of the solvent outlet pipeline. The diameter of the inlet pipeline is half or less of the diameter of the outlet pipeline.

[0016] Furthermore, the routing of the inlet and outlet pipes is such that the included angle between the inlet pipes is less than 90°.

[0017] Compared with the prior art, the present invention has the following advantages: This invention utilizes a coupling change device on the common surface of adjacent chambers to passively balance pressure fluctuations through the coupling change of chamber volume when different solvent pipelines switch solenoid valves. This effectively eliminates the pressure pulsation effect caused by the diaphragm pump effect, significantly improves the accuracy of solvent ratio, ensures that the flow rate of trace solvents is not affected by pressure fluctuations, and greatly improves the accuracy of mixing ratio. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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 based on these drawings without creative effort.

[0019] Figure 1 This is the basic circuit diagram of the present invention.

[0020] Figure 2 The preferred circuit diagram for this invention is shown below.

[0021] Figure 3a This is a schematic diagram of an apparatus with four solvent inlet pipes. Figure 3b for Figure 3a A cross-sectional view along the dashed line.

[0022] Figure 4 The inlet cross-section is shown in Figure 3.

[0023] Figure 5 This is a schematic diagram of a quarter of the passive flow corrector structure in Figure 3.

[0024] Figure 6 This is a schematic diagram of a baffle when there are two solvent inlet pipes.

[0025] Figure 7 This is a schematic diagram of a piston when there are two solvent inlet pipes.

[0026] Figure 8This is a schematic diagram of a baffle when there are three solvent inlet pipes.

[0027] Figure 9 This is a schematic diagram of a piston when there are three solvent inlet pipes.

[0028] Figure 10 This is a schematic diagram of a baffle when there are four solvent inlet pipes.

[0029] Figure 11 This is a schematic diagram of a piston when there are four solvent inlet pipes.

[0030] In the diagram: 1. Solvent inlet pipe; 2. Passive flow corrector; 3. Solenoid valve; 4. Solvent outlet pipe; 5. Chamber; 6. Coupling change device; 7. Inlet channel; 8. Outlet channel; 9. Solvent extension pipe; 10. Solvent premixer; 11. Baffle; 12. Piston. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0035] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0036] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0037] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0038] like Figure 1 and Figure 2 As shown, the present invention provides a passive pressure correction gradient proportional valve, including a plurality of solvent inlet pipes 1, the inlet of each solvent inlet pipe 1 being connected to a solvent channel, and the outlet of each solvent inlet pipe 1 being connected to an inlet channel 7 of a passive flow corrector 2. The passive flow corrector 2 includes several inlet channels 7, outlet channels 8 and chambers 5. Each inlet channel 7 is connected to a chamber 5. The surface between the chamber 5 and the adjacent chamber 5 is a common surface. A coupling change device 6 is provided on the common surface. Each outlet channel 8 is connected to the inlet of a solenoid valve 3. The outlet of the solenoid valve 3 is connected to the inlet of the solvent outlet pipeline 4.

[0039] When the coupling change device 6 is a piston 12, one side of the piston is in contact with the solvent in one chamber 5, and the other side of the piston is in contact with the solvent in another chamber 5. A sealing ring is fitted on the outside of the piston.

[0040] When the coupling change device 6 is a partition 11, the partition is an elastic partition. One side of the partition is in contact with the solvent in one chamber 5, and the other side of the partition is in contact with the solvent in another chamber 5. The material of the partition is one of FFKM, PTFE, or PFA.

[0041] When the volume of chamber 5 on one side of the coupling change device 6 changes, the coupling change device 6 will be displaced or deformed due to the change in pressure on one side, which will cause the volume of chamber 5 on the other side to change.

[0042] The inner wall of the chamber 5 is a smooth inner wall, and the connection between the chamber 5 and the inlet channel 7 and the outlet channel 8 is a rounded transition.

[0043] A solvent extension pipe 9 is provided between the solenoid valve 3 and the solvent outlet pipe 4. The outlet of each solenoid valve 3 is connected to the inlet of one solvent extension pipe 9, and the outlets of all solvent extension pipes 9 are connected to the inlets of the solvent outlet pipe 4. A solvent premixer 10 is provided between the solvent extension pipe 9 and the solvent outlet pipe 4. The outlet of the solvent extension pipe 9 is connected to the inlet pipe of the solvent premixer 10, and the outlet pipe of the solvent premixer 10 is connected to the inlet of the solvent outlet pipe 4. The difference in diameter between the inlet pipe and the outlet pipe is set to be more than twice to achieve low flow resistance from the inlet to the outlet of the solvent premixer.

[0044] like Figure 3a , Figure 3b , Figure 4 and Figure 5As shown, the present invention provides a passive pressure correction gradient proportional valve, comprising multiple solvent inlet pipes 1, each solvent inlet pipe 1 for receiving different types of solvents. Solvents from the solvent inlet pipes 1 are guided through the passive flow corrector 2 itself to one or more chambers 5 with a certain volume. The passive flow corrector 2 includes several inlet channels 7, outlet channels 8, and chambers 5. Each inlet channel 7 is connected to one chamber 5, and adjacent chambers 5 containing different solvents share a common surface, on which a coupling change device 6 is disposed.

[0045] In one embodiment, the coupling change device 6 is a piston disposed at the common surface between adjacent chambers 5, capable of isolating the solvent in the two chambers 5 to prevent leakage, while simultaneously allowing the piston to move freely between the two chambers 5. One side of the piston contacts the solvent in one chamber 5, and the other side contacts the solvent in the other chamber 5. In a further preferred embodiment, the piston is made of a wear-resistant and corrosion-resistant material, and to enhance the isolation effect, the piston can be used in conjunction with a sealing ring.

[0046] In another embodiment, the coupling change device 6 is an elastic partition. This partition is positioned at the common surface between adjacent chambers 5, effectively isolating the solvent within the two chambers 5 while possessing a certain degree of elastic deformation capability. One side of the partition contacts the solvent in one chamber 5, and the other side contacts the solvent in the other chamber 5. The partition is made of an elastic and corrosion-resistant material, such as FFKM, PTFE, or PFA, and during assembly, the partition is pressed tightly against the chambers 5 to ensure effective isolation.

[0047] The aforementioned piston or elastic diaphragm configuration allows the volumes of the two chambers 5 on the common surface to change in a coupled manner; that is, when the volume of one chamber 5 increases, the volume of the other chamber 5 decreases accordingly. When the solenoid valve 3 switches, the pressure in the closed solvent line increases, and the pressure in the open solvent line decreases. The piston or elastic diaphragm can respond to the pressure change on both sides by displacement or deformation, thereby realigning the solvent pressure on both sides, effectively reducing pressure pulsation caused by the diaphragm pump effect, and improving the accuracy of solvent mixing.

[0048] Each chamber 5 has an inlet and an outlet. The inner wall of chamber 5 is smooth, and the inlet and outlet are rounded to reduce pressure loss caused by changes in flow velocity.

[0049] The gradient proportional valve of this invention also includes multiple solenoid valves 3, the number of which corresponds to the number of solvent inlet pipes 1. The inlet of each solenoid valve 3 is connected to one outlet channel 8 of the passive flow corrector 2, and the outlet of each solenoid valve 3 is connected to the inlet of the solvent outlet pipe 4. The solenoid valve 3 controls the opening or closing of its respective pipe by receiving different voltage signals, exhibiting a millisecond-level response speed. One solvent outlet pipe 4 is provided for discharging the mixed solvent composition.

[0050] In a preferred embodiment, a solvent extension pipe 9 is provided between the solenoid valve 3 and the solvent outlet pipe 4. The outlet of each solenoid valve 3 is connected to the inlet of one solvent extension pipe 9, and the outlets of all solvent extension pipes 9 are connected to the inlet of the solvent outlet pipe 4. The length of the solvent extension pipe 9 can be set to 50~300mm to reduce the mutual influence between different solvent pipes during the diaphragm pump effect.

[0051] In a further preferred embodiment, a solvent premixer 10 is provided between the solvent extension line 9 and the solvent outlet line 4. The outlet of the solvent extension line 9 is connected to the inlet line of the solvent premixer 10, and the outlet line of the solvent premixer 10 is connected to the inlet of the solvent outlet line 4. The diameter difference between the inlet and outlet lines of the solvent premixer 10 is set to be more than twice, and the orientation of the inlet and outlet lines is set to a form with high flow resistance between the inlets, for example, the angle between adjacent inlet lines is less than 90°. With the above structure, the solvent premixer 10 can further reduce the mutual influence between different solvent lines during the diaphragm pump effect, making the mixed solvent composition more uniform and stable.

[0052] Figure 6 This is a schematic diagram of a two-cavity coupling method using an elastic partition. Figure 7 This is a schematic diagram of a two-chamber coupling method using a piston. Figure 8 This is a schematic diagram of a three-cavity, two-by-two coupling method using elastic partitions. Figure 9 This is a schematic diagram of a three-chamber system using a piston with two chambers coupled together. Figure 10 This is a schematic diagram of a four-cavity, two-by-two coupling method using elastic partitions. Figure 11 This is a schematic diagram of a four-chamber system using a piston with two chambers coupled together.

[0053] 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 passive pressure-corrected gradient proportional valve, characterized in that, include: Several solvent inlet pipes, each solvent inlet pipe has its inlet connected to a solvent channel, and each solvent inlet pipe has its outlet connected to an inlet channel of a passive flow corrector. The passive flow corrector includes several inlet channels, outlet channels, and chambers. Each inlet channel is connected to a chamber, and the surfaces between adjacent chambers are common surfaces. A coupling change device is provided on the common surface. Each outlet channel is connected to the inlet of a solenoid valve, and the outlet of the solenoid valve is connected to the inlet of the solvent outlet pipeline.

2. The passive pressure correction gradient proportional valve according to claim 1, characterized in that, The coupling change device is a piston, one side of which is in contact with the solvent in one chamber, and the other side of which is in contact with the solvent in another chamber.

3. The passive pressure correction gradient proportional valve according to claim 1, characterized in that, The coupling change device is a partition, which is an elastic partition. One side of the partition is in contact with the solvent in one chamber, and the other side of the partition is in contact with the solvent in another chamber.

4. The passive pressure correction gradient proportional valve according to claim 1, characterized in that, When the volume of the chamber on one side of the coupling change device changes, the coupling change device will be displaced or deformed due to the change in pressure on one side, which will cause the volume of the chamber on the other side to change.

5. The passive pressure correction gradient proportional valve according to claim 1, characterized in that, The inner wall of the chamber is smooth, and the connection between the chamber and the inlet and outlet channels is a rounded transition.

6. The passive pressure correction gradient proportional valve according to claim 2, characterized in that, The piston is fitted with a sealing ring on its outer side.

7. The passive pressure correction gradient proportional valve according to claim 3, characterized in that, The material of the partition is one of FFKM, PTFE or PFA.

8. The passive pressure correction gradient proportional valve according to claim 1, characterized in that, A solvent extension pipeline is provided between the solenoid valve and the solvent outlet pipeline. The outlet of each solenoid valve is connected to the inlet of a solvent extension pipeline, and the outlets of all solvent extension pipelines are connected to the inlet of the solvent outlet pipeline.

9. The passive pressure correction gradient proportional valve according to claim 8, characterized in that, A solvent premixer is provided between the solvent extension pipeline and the solvent outlet pipeline. The outlet of the solvent extension pipeline is connected to the inlet pipeline of the solvent premixer, and the outlet pipeline of the solvent premixer is connected to the inlet of the solvent outlet pipeline. The diameter of the inlet pipeline is half or less of the diameter of the outlet pipeline.

10. The passive pressure correction gradient proportional valve according to claim 9, characterized in that, The routing of the inlet and outlet pipes should be such that the included angle between the inlet pipes is less than 90°.

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