Bubble collecting device for liquid chromatograph

Abstract

This invention provides a bubble collection device for liquid chromatographs, comprising an observation section and a solvent delivery section connected together. The observation section is positioned above the solvent delivery section. The observation section is a polyhedral structure with an inclined surface, and an internal cavity is provided. The opening of the cavity is located on the inclined surface. A discharge pipe is provided inside the observation section, with its opening located on the upper surface of the observation section. The discharge pipe is connected to the cavity. The inner wall of the cavity protrudes inward to form a first mounting platform and a second mounting platform. The solvent delivery section is a cuboid, and has a solvent inflow path and a solvent outflow path. This invention achieves effective retention and collection of large, visible bubbles in the mobile phase, fundamentally preventing such bubbles from entering the pump body and subsequent flow paths, thereby ensuring the continuity and stability of high-performance liquid chromatography analysis.

Description

Technical Field

[0001] This invention relates to the field of liquid chromatography analysis technology, and more particularly to a bubble collection device for a liquid chromatograph. Background Technology

[0002] High-performance liquid chromatography (HPLC) is an analytical technique widely used in chemistry, biology, and medicine. Its core principle lies in using a mobile phase to deliver samples through a chromatographic column under high pressure, achieving the separation and detection of components. During HPLC analysis, the stability of the mobile phase is crucial, and dissolved or introduced air bubbles can severely affect the accuracy of analytical results and the normal operation of the instrument. Air bubbles can cause fluctuations in the flow rate of the delivery system, increased detector baseline noise, false peaks, and even damage to expensive chromatographic columns. Therefore, mobile phase degassing is an indispensable pretreatment step in HPLC analysis.

[0003] Currently, the industry widely uses "online vacuum degassing devices" as the primary means of removing air bubbles from the mobile phase. These devices are typically installed before the mobile phase delivery system, using vacuum negative pressure to remove or reduce dissolved gases and small air bubbles (generally less than 10 μm) in the mobile phase. Furthermore, when changing solvent bottle filter heads or mobile phase solutions, operators often use high-flow-rate filling lines to attempt to expel any larger air bubbles that may be generated, thus minimizing their impact on the system.

[0004] However, existing technologies have significant shortcomings. First, "online vacuum degassing devices" primarily target dissolved gases and tiny bubbles, with limited effectiveness in removing larger, visible bubbles. Second, during the perfusion degassing process, bubbles are easily introduced into the pump body and subsequent flow paths. Due to the pump structure and fluid properties (such as the high viscosity and surface tension of pure water), complete bubble removal often takes 5 to 10 minutes or even longer, severely impacting analytical efficiency. Furthermore, factors such as ambient temperature, gas pressure changes, or negative pressure at the filter head can continue to generate larger bubbles, making it difficult to completely prevent their entry into the system even with a degassing device, leading to detection interruptions or reduced result reliability. Therefore, an auxiliary device capable of effectively collecting and removing larger bubbles is urgently needed to improve the stability and efficiency of HPLC systems. Summary of the Invention

[0005] To address the aforementioned technical problems of existing degassing devices' ineffective removal of large air bubbles from the mobile phase, and the low efficiency and tendency of conventional perfusion degassing methods to introduce air bubbles into the pump body, this invention provides a bubble collection device for liquid chromatography. This invention primarily utilizes bubble collection devices positioned before and after the degassing device, featuring a cavity structure with a specific tilt angle and a transparent observation port at the top. This achieves the retention, collection, and visual management of large air bubbles, effectively preventing them from entering the chromatographic pump body and subsequent flow paths, thus ensuring the continuous, stable, and efficient operation of the liquid chromatography system.

[0006] The technical means employed in this invention are as follows: A bubble collection device for a liquid chromatograph includes an observation section and a solvent delivery section connected together, wherein the observation section is disposed above the solvent delivery section; The observation section is a polyhedral structure with an inclined surface. A cavity is provided inside the observation section, with the opening of the cavity located on the inclined surface. A discharge pipe is provided inside the observation section, with its opening located on the upper surface of the observation section. The discharge pipe is connected to the cavity and has a cap. The inner wall of the cavity protrudes inward to form a first mounting platform and a second mounting platform. The second mounting platform is located above the first mounting platform. An observation seal is connected to the first mounting platform, and a sealing pressure plate is connected to the second mounting platform. The cavity above the second mounting platform is connected to a spun-top cover, which is a hollow structure. The bottom of the spun-top cover is in contact with the sealing pressure plate. The solvent delivery section is a cuboid, and a solvent inflow path and a solvent outflow path are respectively opened in the solvent delivery section. The openings of the solvent inflow path and the solvent outflow path are located on the front surface of the solvent delivery section, and the solvent inflow path and the solvent outflow path are connected to the cavity.

[0007] Furthermore, taking the direction facing the inclined plane as the front, the observation part is a right-angled trapezoidal structure, the left and right sides of the observation part are trapezoidal, the width of the upper plane of the observation part is smaller than the width of the lower plane of the observation part, and the width of the lower plane of the observation part is smaller than the width of the upper plane of the solvent delivery part.

[0008] Furthermore, the cavity is cylindrical or cylindrical with a conical structure at the bottom.

[0009] Furthermore, the axis of the cavity is perpendicular to the inclined plane.

[0010] Furthermore, the observation cover is made of one of the following materials: polytetrafluoroethylene, tetrafluoroethylene, or fluorinated ethylene propylene copolymer.

[0011] Furthermore, the first mounting platform is recessed downwards at the junction with the inner wall of the cavity to form a sealing groove.

[0012] Furthermore, the second mounting platform is provided with a limiting groove, which is arranged in a straight line or a cross shape.

[0013] Furthermore, the bottom outer side of the spun top cover is chamfered.

[0014] Furthermore, a lighting device is provided next to the cavity.

[0015] Furthermore, the observation section and the solvent delivery section are an integrated structure, and the materials of the observation section and the solvent delivery section are fluorinated resin materials or stainless steel materials.

[0016] Compared with the prior art, the present invention has the following advantages: This invention achieves effective retention and collection of large, visible bubbles in the mobile phase by setting a cavity structure with a specific tilt angle before and after the online vacuum degassing device. This fundamentally prevents such bubbles from entering the pump body and subsequent flow paths, thereby ensuring the continuity and stability of high-performance liquid chromatography analysis.

[0017] This invention enables real-time and convenient observation of the volume of bubbles and the state of the solution inside the cavity by setting an observation port at the top of the cavity and a controllable LED light source at the bottom. This allows operators to keep abreast of the situation and plan maintenance without interrupting analysis.

[0018] This invention achieves a transformation from surface sealing to line sealing by combining a grooved observation sealing plate mounting platform with a sealing pressure plate with a limiting structure. This not only improves sealing reliability but also eliminates dead volume and effectively prevents cross-contamination when different solvents are changed. Attached Figure Description

[0019] 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.

[0020] Figure 1 This is a perspective view of the present invention.

[0021] Figure 2 This is an exploded view of the present invention.

[0022] Figure 3 This invention is shown in a side cross-sectional view.

[0023] In the diagram: 1. Cavity; 2. Inclined surface; 3. Discharge pipe; 4. Screw cap; 5. First mounting platform; 6. Second mounting platform; 7. Top cap; 8. Solvent inflow path; 9. Solvent outflow path; 10. Illumination device; 11. Observation seal; 12. Sealing press. Detailed Implementation

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] like Figure 1 As shown, the present invention provides a bubble collection device for a liquid chromatograph, including an observation section and a solvent delivery section connected together, wherein the observation section is disposed above the solvent delivery section; The observation section is a polyhedral structure with an inclined surface 2. A cavity 1 is provided inside the observation section. The opening of the cavity 1 is located on the inclined surface 2. A discharge pipe 3 is provided inside the observation section. The opening of the discharge pipe 3 is located on the upper surface of the observation section. The discharge pipe 3 is connected to the cavity 1. A screw cap 7 is provided on the discharge pipe 3. The inner wall of the cavity 1 protrudes inward to form a first mounting platform 5 and a second mounting platform 6. The second mounting platform 6 is located above the first mounting platform 5. An observation sealing plate 11 is connected to the first mounting platform 5. A sealing pressure plate 12 is connected to the second mounting platform 6. The cavity 1 above the second mounting platform 6 is connected to a spun top cover 4. The spun top cover 4 is a hollow structure. The bottom of the spun top cover 4 is in contact with the sealing pressure plate 12. The solvent delivery section is a cuboid, and a solvent inflow path 8 and a solvent outflow path 9 are respectively opened in the solvent delivery section. The openings of the solvent inflow path 8 and the solvent outflow path 9 are located on the front surface of the solvent delivery section, and the solvent inflow path 8 and the solvent outflow path 9 are connected to the cavity 1.

[0032] With the direction facing the inclined plane 2 as the front, the observation part is a right-angled trapezoidal structure. The left and right sides of the observation part are trapezoidal. The width of the upper plane of the observation part is smaller than the width of the lower plane of the observation part, and the width of the lower plane of the observation part is smaller than the width of the upper plane of the solvent delivery part.

[0033] Cavity 1 is used to store and retain larger air bubbles in the mobile phase solution. Cavity 1 is cylindrical or cylindrical with a conical bottom for easy machining. It is housed in a thermoplastic or machined base, which serves as both the observation section and the solvent delivery section. The base can be made of fluoropolymer, stainless steel, or other corrosion-resistant materials. The sides of the base have a trapezoidal structure, but a plane perpendicular to the bottom surface at the lower end on the observation port side for installing inlet / outlet tubing. The axis of cavity 1 forms a 45° angle (or approximate value) with the bottom surface of the base and is perpendicular to the inclined plane 2 on the observation port side, allowing for a comfortable viewing angle. The internal volume of cavity 1 can be set to 500–1000 μL to simultaneously provide sufficient space for bubble containment and accommodate a short solution replacement time. Typically, the flow rate at the inlet of cavity 1 is above 2 mL / min. The time required to completely replace the solution in cavity 1 (calculated based on 5 times the volume of cavity 1) is: T = 5 × V 空 / 2mL / min=1.25~2.5min A transparent or translucent observation cover 11 is provided at the top of the cavity 1 for observing the volume of air bubbles stored and retained within the cavity. The observation cover 11 can be made of any flexible or semi-rigid transparent or translucent film material to facilitate sealing and observation, and should be resistant to organic solvent corrosion, including but not limited to inert fluoropolymers such as polytetrafluoroethylene (PTFE), polytetrafluoroethylene (PFA), and fluorinated ethylene propylene copolymer (FEP). It is a circular sheet with a thickness of 0.2–0.35 mm and a diameter equal to or slightly smaller than the diameter of the first mounting platform 5 of the observation cover 11.

[0034] The first mounting platform 5, located approximately 0.5 mm from the inner wall of the cavity 1, has a groove concentric with the cavity 1. This groove changes the contact between the observation seal 11 and the mounting platform from surface contact to line contact. When the limiting sealing pressure plate 12 applies vertical force to press down the sealing diaphragm, the seal between the observation seal 11 and the platform changes from a surface seal to a line seal, thus providing a better sealing effect. Furthermore, this sealing structure prevents the accumulation of unreplaceable solvent between the observation seal 11 and the first mounting platform 5, eliminating the risk of cross-contamination during solvent replacement. Above the first mounting platform 5, a second mounting platform 6 is provided to support and limit the sealing pressure plate 12. Its diameter is slightly larger than or equal to that of the limiting sealing pressure plate 12, and its height is slightly less than the thickness of the sealing pressure plate 12. On this second mounting platform 6, grooves are provided to prevent the sealing plate 12 from rotating. There are two grooves (in a linear layout) or four grooves (in a cross-shaped layout). When the limiting point of the sealing plate 12 with a limiting feature is embedded in the groove, even if the upper cover 4 is rotated downwards to press the sealing plate 12, the sealing plate 12 will not rotate, thus protecting the sealing film from damage due to friction. The sealing plate 12 is made of stainless steel to ensure sufficient strength. It is a ring with a thickness of approximately 1 mm and a linear or cross-shaped limiting flange. Its outer diameter is the same as the diameter of the sealing film, and its inner diameter is slightly smaller than the inner diameter of the cavity 1 by 1 to 1.5 mm.

[0035] Above the second mounting platform 6 is a threaded cylindrical cavity 1, the diameter of which is the same as the outer edge diameter of the second mounting platform 6 and concentric with the cavity 1, for the installation of the top cover 4. The top cover 4 resembles a bolt in shape, but has a hollow internal structure to provide a viewing hole. Its diameter is slightly smaller than or equal to the inner diameter of the sealing plate 12. It can be installed by hand-tightening (with anti-slip vertical grooves at the round nut) or by tightening with a metric hexagonal or internal hexagonal wrench. It can be made of stainless steel or PEEK, or other materials with a certain rigidity and resistance to organic solvent corrosion. The bottom of the top cover 4 (the end in contact with the sealing plate 12) has a chamfer at 45° to the axis of the inner hole on the threaded side (outer side), so that the bottom of the top cover and the contact surface of the sealing plate 12 are approximately in line contact, and it presses positively on the flange of the sealing film mounting platform.

[0036] The top of cavity 1 is also equipped with a drain pipe 3 and a cap 7 for discharging air bubbles and solution, facilitating solution replacement and air bubble discharge when the solution type is changed. The upper edge of the drain hole should be as close as possible to the upper edge of cavity 1, and symmetrically positioned at the center of the top. When air bubbles in the bubble collection chamber are observed to affect the normal operation of the test, the cap 7 of the drain pipe 3 should be opened when the test is stopped. At this time, the mobile phase solution will gradually fill cavity 1 with solution under the action of gravity, and expel excess air bubbles. After the air bubbles are completely expelled, the cap 7 should be closed, and normal testing can continue. When changing the type of mobile phase solution, first remove the cap 7 of the drain pipe 3, first drain the original solution in the bubble collection cavity 1 through the mobile phase solution inlet, then connect the new solution pipe to the inlet. When the solution fills cavity 1 and is about to overflow from the drain pipe 3, disconnect the new solution pipe again and drain the solution in cavity 1 through the inlet. Repeat this process 4-5 times to complete the replacement of the original solution in the cavity. Because the vent is positioned higher than the highest point of the collecting cavity 1, complete replacement of the entire cavity without any residue can be achieved. The fact that the drain pipe 3 cap 7 can be connected to the inlet and outlet pipe interfaces is also a feature of this invention. As another method of discharging the replacement solution, after the initial filling with new solution, the inlet pipe can be directly connected to the drain pipe 3, utilizing gravity to continuously replace the solution within the cavity.

[0037] A controllable lighting device 10 is provided at the bottom of cavity 1 or other locations that can provide illumination for easy observation through the observation port, and has a settable automatic shut-off time to facilitate observation of the volume of solution / bubbles inside the cavity.

[0038] At the bottom of cavity 1, there are inlets and outlets for the flow of the mobile phase solution. The inlets are located on the side of the observation port, on a plane perpendicular to the bottom surface, and have a diameter of 0.8–1.3 mm. The direction of the flow path is parallel to the bottom surface of the solvent delivery section. A certain distance should be maintained between the inlet and outlet inlets at the bottom of cavity 1 to provide space for bubbles to rise and prevent bubbles flowing into the cavity from being drawn back into the outlet pipe.

[0039] Preferably, the solvent inflow path 8 of the above-mentioned solvent should be set as an elliptical outlet to increase the orifice area of ​​the inflow path 8 and increase the bubble adhesion area, so that the formed bubbles have a larger volume and a faster rising speed.

[0040] Preferably, the solvent outflow path 9 of the above solvent should be set as an elliptical outlet to increase the orifice area, so as to reduce the negative pressure around the outflow orifice when the liquid is drawn in, and to prevent the air bubbles discharged from the inflow orifice from being drawn in again by the outflow orifice.

[0041] Meanwhile, the residual problem of solution displacement should be considered. Therefore, the outer wall of the solvent inflow path 8 should be close to the lower edge of the cavity 1, located directly below the center of the vent hole. The solvent outflow path 9 should be slightly higher than the solvent inflow path 8, and the outer edge of the hole should be tangent to the inner wall of the cylindrical cavity 1 to achieve the maximum internal cavity area.

[0042] As one implementation scheme: When the bubble collection device described in this invention is configured at the front end of the "online vacuum degassing device", combined with the invention patent "A method for detecting missing mobile phase solution through a degassing unit (CN120468315A)" published by Huapu Scientific Instruments (Beijing) Technology Co., Ltd., since the bubble collection chamber can effectively prevent large-volume bubbles from entering the "online vacuum degassing device", the upper limit of bubble tolerance (size) in this detection method can be reduced without increasing the false alarm rate, thereby improving the detection accuracy and detection speed of missing mobile phase.

[0043] As another implementation: When the bubble collection device described in this invention is configured at the rear end of an "online vacuum degassing device," and in conjunction with the published invention patent "A method for detecting missing mobile phase solution through a degassing unit (CN120468315A)" by Huapu Scientific Instruments (Beijing) Technology Co., Ltd., the presence of a buffer solution in the cavity helps to extend the detection reaction time for missing mobile phase or the number of repeated verification judgments, thereby improving the detection accuracy of missing mobile phase. Simultaneously, it reduces the probability of bubbles entering the pump body.

[0044] The bubble collecting device described in this invention can be installed as an independent device with the specific functions described in this patent within a high-performance liquid chromatography (HPLC) system. Furthermore, it can be combined with other components such as an online vacuum degassing device, a selector valve, or a proportional valve to achieve additional functions beyond its basic purpose, as mentioned in this patent.

[0045] 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 bubble collecting device for a liquid chromatograph, characterized in that: It includes an observation section and a solvent delivery section connected together, with the observation section disposed above the solvent delivery section; The observation part is a polyhedral structure with an inclined surface (2). The observation part has a cavity (1) inside. The opening of the cavity (1) is located on the inclined surface (2). The observation part has a discharge pipe (3) inside. The opening of the discharge pipe (3) is located on the upper surface of the observation part. The discharge pipe (3) is connected to the cavity (1). The discharge pipe (3) is provided with a screw cap (7). The middle of the inner wall of the cavity (1) protrudes inward to form a first mounting platform (5) and a second mounting platform (6). The second mounting platform (6) is located above the first mounting platform (5). The first mounting platform (5) is connected to an observation sealing plate (11). The second mounting platform (6) is connected to a sealing pressure plate (12). The cavity (1) above the second mounting platform (6) is connected to a spun top cover (4). The spun top cover (4) is a hollow structure. The bottom of the spun top cover (4) is in contact with the sealing pressure plate (12). The solvent delivery section is a cuboid, and a solvent inflow path (8) and a solvent outflow path (9) are respectively provided in the solvent delivery section. The openings of the solvent inflow path (8) and the solvent outflow path (9) are located on the front surface of the solvent delivery section. The solvent inflow path (8) and the solvent outflow path (9) are connected to the cavity (1).

2. The bubble collection device for liquid chromatograph according to claim 1, characterized in that, With the direction facing the inclined plane (2) as the front, the observation part is a right trapezoidal structure. The left and right sides of the observation part are trapezoidal. The width of the upper plane of the observation part is smaller than the width of the lower plane of the observation part. The width of the lower plane of the observation part is smaller than the width of the upper plane of the solvent delivery part.

3. The bubble collection device for liquid chromatograph according to claim 1, characterized in that, The cavity (1) is cylindrical or cylindrical with a conical structure at the bottom.

4. The bubble collection device for liquid chromatograph according to claim 3, characterized in that, The axis of the cavity (1) is perpendicular to the inclined plane (2).

5. The bubble collection device for liquid chromatograph according to claim 1, characterized in that, The observation cover (11) is made of one of the following materials: polytetrafluoroethylene, tetrafluoroethylene, or fluorinated ethylene propylene copolymer.

6. The bubble collection device for liquid chromatograph according to claim 1, characterized in that, The first mounting platform (5) is recessed downward at the junction with the inner wall of the cavity (1) to form a sealing groove.

7. The bubble collecting device for a liquid chromatograph according to claim 1, characterized in that, The second installation platform (6) is provided with a limiting groove, which is arranged in a straight line or a cross shape.

8. The bubble collection device for a liquid chromatograph according to claim 1, characterized in that, The bottom outer side of the spun top cover (4) is chamfered.

9. The bubble collection device for a liquid chromatograph according to claim 1, characterized in that, A lighting device (10) is provided next to the cavity (1).

10. The bubble collecting device for a liquid chromatograph according to claim 1, characterized in that, The observation section and the solvent delivery section are an integrated structure, and the materials of the observation section and the solvent delivery section are fluorinated resin materials or stainless steel materials.

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