阅读说明：本技术 一种液相色谱高压输液泵泵头压力分级系统及其控制方法 (Pump head pressure grading system of liquid chromatography high-pressure infusion pump and control method thereof ) 是由 周雅雯 林雪志 张杨康 周小靖 于 2020-05-21 设计创作，主要内容包括：一种液相色谱高压输液泵泵头压力分级系统及其控制方法,按清洗液流动方向,依次包括溶液瓶、清洗泵、输液泵、压力传感器、背压设备及废液瓶,所述输液泵包括后部的柱塞杆驱动机构和前部的泵头、泵头座及柱塞杆,泵头与泵头座之间设有清洗泵头,清洗泵头内设有清洗腔,清洗腔连接有两个清洗接头,柱塞杆前端穿过清洗泵头进入到泵头内,清洗泵头与泵头之间设有第一密封圈,清洗腔后部的清洗泵头内设有第二密封圈。本发明采用在结构上制造密封圈压力分级的方式,减小第一密封圈在使用过程中的形变,减少密封圈在交变应力下的疲劳损坏,减少漏液并延迟密封圈使用寿命。另附带高压清洗功能,通过增加清洗液压力提高溶剂置换效率,能有效将缓冲盐溶液中的缓冲盐扩散到清洗液中,保护柱塞杆和密封圈表面。(The utility model provides a liquid chromatogram high pressure infusion pump head pressure classification system and control method, according to the washing liquid flow direction, include solution bottle, scavenging pump, transfer pump, pressure sensor, backpressure equipment and waste liquid bottle in proper order, the transfer pump includes the plunger rod actuating mechanism and the anterior pump head of rear portion, pump head seat and plunger rod, is equipped with the scavenging pump head between pump head and the pump head seat, is equipped with the washing chamber in the washing pump head, and the washing chamber is connected with two and washs the joint, and the plunger rod front end passes in the washing pump head enters into the pump head, washs and is equipped with first sealing washer between pump head and the pump head, is equipped with the second. The invention adopts a mode of manufacturing the sealing ring in a structure and grading pressure, reduces the deformation of the first sealing ring in the using process, reduces the fatigue damage of the sealing ring under the alternating stress, reduces the liquid leakage and prolongs the service life of the sealing ring. In addition, the high-pressure cleaning function is added, the solvent replacement efficiency is improved by increasing the pressure of the cleaning liquid, the buffer salt in the buffer salt solution can be effectively diffused into the cleaning liquid, and the surfaces of the plunger rod and the sealing ring are protected.)

1. The utility model provides a liquid chromatogram high pressure transfer pump head pressure classification system which characterized in that: grading system includes solution bottle (10), scavenging pump (20), transfer pump (30), pressure sensor (50), backpressure equipment (40) and waste liquid bottle (60) according to the washing liquid flow direction in proper order, transfer pump (30) are equipped with between pump head (31) and the pump head seat (32) and wash pump head (36) including plunger rod actuating mechanism and anterior pump head (31), pump head seat (32) and plunger rod (33) at rear portion, be equipped with between pump head (31) and the pump head seat (32) and wash chamber (36.1), wash chamber (36.1) and be connected with two and wash and connect (36.2), plunger rod (33) front end passes and washes in pump head (36) enters into pump head (31), it is equipped with first sealing washer (37) to wash between pump head (36) and the pump head (31), it is equipped with second sealing washer (38) in washing pump head (36) at washing chamber (36..

2. A liquid chromatography high pressure infusion pump head pressure fractionation system as claimed in claim 1, wherein: a bypass valve (80) is arranged on a pipeline between the backpressure device (40) and the waste liquid bottle (60), and the bypass valve (80) is connected with the solution bottle (10).

3. A liquid chromatography high pressure infusion pump head pressure fractionation system as claimed in claim 2, wherein: the grading system also includes a controller (70).

4. A liquid chromatography high pressure infusion pump head pressure fractionation system as claimed in claim 1, wherein: the front end of the cleaning cavity (36.1) is in a tapered structure which is gradually reduced.

5. A control method of a pump head pressure grading system of a liquid chromatography high-pressure infusion pump is characterized by comprising the following steps:

s001, before the system starts to work, setting a partial pressure ratio of a cleaning fluid flow path or a pressure-bearing value of a first sealing ring (37) according to use requirements;

s002, reading the pressure of the mobile phase flow path and sending the pressure to a controller (70), calculating by the controller (70) according to the pressure of the mobile phase flow path and the set partial pressure proportion or pressure bearing value to obtain the working pressure of the cleaning liquid in the grading system, and calculating by a pressure-flow model to obtain the working default flow rate of the cleaning pump (20);

s003, starting a cleaning pump (20) at a default flow rate, enabling cleaning liquid to flow out of a solution bottle (10), conveying the cleaning liquid to a cleaning pump head (36) and a back pressure device (40) of an infusion pump (30) through the cleaning pump (20), pressurizing the cleaning liquid between the cleaning pump (20) and the back pressure device (40), cleaning a plunger rod (33) under the condition of certain pressure, and enabling the cleaning liquid to flow into a waste liquid bottle (60) through the back pressure device (40);

s004, reading the actual pressure of the cleaning liquid flow path by the pressure sensor (50) and sending the actual pressure to the controller (70);

and S005, judging whether the actual pressure of the cleaning liquid flow path is within a set working pressure threshold range or not by the controller (70), if so, keeping the working flow rate of the cleaning pump (20) unchanged, and if not, calculating a proper working flow rate by the controller (70) and controlling the cleaning pump (20) to adjust.

6. The method for controlling the pressure classification system of the pump head of the liquid chromatography high-pressure infusion pump according to claim 5, wherein the method comprises the following steps: after the system works, the pressure of the mobile phase flow path is read from time to time and sent to the controller (70), and the controller (70) calculates the corresponding working pressure of the cleaning pump (20) according to the pressure of the mobile phase flow path and controls the cleaning pump (20) to adjust.

7. The method for controlling the pressure classification system of the pump head of the liquid chromatography high-pressure infusion pump according to claim 5, wherein the method comprises the following steps: in step S003, the controller 70 controls the bypass valve 80 to select the flow of the cleaning liquid into the waste liquid bottle 60 or the solution bottle 10.

Technical Field

The invention belongs to the technical field of infusion pumps, and particularly relates to a pump head pressure grading system of a liquid chromatography high-pressure infusion pump and a control method thereof.

Background

High pressure infusion pumps are key components of High Performance Liquid Chromatography (HPLC) systems. The plunger rod and the sealing ring are core components which have very high processing requirements and play an especially important role in normal operation of the system, however, in the actual use process, the plunger rod and the sealing ring are always in motion in the operation process of the infusion pump due to long-term contact with the flowing liquid, and the plunger rod and the sealing ring are also the most vulnerable. Therefore, in a typical liquid chromatography system, these two components are defined as consumables and need to be replaced periodically, with a common replacement period of one year. Replacement under harsh conditions and with ultra high performance liquid chromatography systems (UHPLC) is more frequent.

The seal ring is typically made of an elastomeric material that deforms under pressure when the system pressure increases. The plunger rod and the pump sleeve matched with the sealing ring are made of hard materials and cannot absorb deformation, so that the sealing ring is continuously switched between a normal state and a pressed deformation state in the operation process of the infusion pump, and fatigue damage is generated under alternating stress. In an Ultra High Performance Liquid Chromatography (UHPLC) system, the pressure of a common system is far higher than that of a common High Performance Liquid Chromatography (HPLC), namely, the deformation amount of a sealing ring is larger in the process of alternately sucking and infusing liquid. The deformation can cause changes in the internal volume of the seal ring, resulting in unstable system pressure. If the amount of deformation exceeds the limit, the sealing ring may not be able to completely pinch the plunger rod, resulting in the mobile phase leaking out of the gap between the two. And the UHPLC system mainly performs rapid separation analysis, and for the rapid separation analysis, the obvious difference of results can be caused by small difference of the system.

Currently, for the problem of the seepage of a mobile phase under ultrahigh pressure, a UHPLC usually adopts a program to compensate the flow rate so as to ensure the infusion precision. The method needs to respectively correct different mobile phase compositions, and needs a large amount of modeling to ensure the reliability of data. In addition, although the problem of sample analysis repeatability is solved, the mobile phase continuously seeps out and volatilizes into the air, so that pollution exists.

Furthermore, when the system uses buffer salts as the mobile phase, a small amount of buffer is carried by the plunger rod out of the sealing ring and into contact with air as the plunger rod reciprocates. As the liquid in the buffer solution evaporates, the particles of crystallized buffer salt will adhere to the surface of the plunger rod. The particles are rubbed back and forth on the inner surface of the sealing ring along with the reciprocating motion of the plunger rod, and irreversible damage can be caused to the surface of the sealing ring.

At present, a cleaning pump is added to reduce abrasion of a sealing ring by buffer salt crystal grains attached to the surface of a plunger rod, pure water or a solution with a large amount of water phase is used as a cleaning solution, and the plunger rod is flushed by starting the cleaning pump while a buffer salt solution is conveyed by a conveying pump. However, the contact area between the cleaning liquid and the plunger rod is limited, the gap between the circular hole of the cleaning pump head and the plunger rod is narrow, the surface tension of the liquid exists, the cleaning liquid is difficult to enter the space between the sealing ring and the plunger rod, and the buffer salt solution between the sealing ring and the plunger rod is thoroughly cleaned.

In the case of pure water, the contact angle θ =75 ° with water on the surface of stainless steel at room temperature (20 ℃), and the contact angle with the surface of the plunger rod (calculated on the smooth glass surface) is also less than 90 °. Therefore, when cleaning liquid enters a gap between the cleaning pump head and the plunger rod, the liquid level is a concave liquid level, and only the surface of the limited plunger rod can be cleaned, so that the cleaning liquid cannot deeply clean. The position of the buffer salt is close to the sealing ring, and the buffer salt cannot be completely carried out only by cleaning the surface of the limited plunger rod, or the separated buffer salt is accumulated step by step along with the operation of the infusion pump, so that the effects of cleaning the surface of the plunger rod and protecting the sealing ring are limited.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a pump head pressure dividing system of a liquid chromatography high-pressure plunger infusion pump and a control method thereof, and designs a system capable of prolonging the service life of a plunger rod and a sealing ring, so that the plunger rod and the sealing ring are not used as consumable parts which are frequently replaced any more.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the utility model provides a liquid chromatogram high pressure infusion pump head pressure grading system, the system includes solution bottle, scavenging pump, transfer pump, pressure sensor, backpressure equipment and waste liquid bottle according to the washing liquid flow direction in proper order, the transfer pump includes the plunger rod actuating mechanism and the anterior pump head, pump head seat and the plunger rod at rear portion, is equipped with the washing pump head between pump head and the pump head seat, is equipped with the washing chamber in the washing pump head, and the washing chamber is connected with two washing joints, and the plunger rod front end is passed and is washd in the pump head enters into the pump head, washs and is equipped with first sealing washer between pump head and the pump head, washs and. The back pressure equipment ensures that a cleaning fluid flow path where the infusion pump is located has higher pressure so as to improve the cleaning effect, the first sealing ring and the second sealing ring are both high-pressure sealing rings, and the cleaning pump is a high-pressure cleaning pump.

Preferably, the back pressure device may be a back pressure pipe, a back pressure valve, or the like.

Preferably, a bypass valve is arranged on a pipeline between the backpressure device and the waste liquid bottle, and the bypass valve is connected with the solution bottle. The bypass valve can make the cleaning solution flow back to the solution bottle, and the cleaning solution can be recycled.

Preferably, the grading system further comprises a controller for controlling the operation of the system.

Preferably, the front end of the cleaning cavity is of a tapered structure which is gradually reduced, so that the cleaning liquid can enter the cleaning pump head more easily. The action that original washing liquid enters into in the gap can be approximate to be the different pipeline direct contact of two diameters, and the pipe diameter reduces suddenly, because the gap is minimum, local resistance coefficient is close 1, because the existence of toper structure chamfer, the action that the washing liquid enters into in the gap can be approximate to the fillet import, local resistance coefficient 0.25, and the washing liquid is changeed and is got into, increases the washing area.

A control method of a pump head pressure grading system of a liquid chromatography high-pressure infusion pump comprises the following steps:

and S001, before the grading system starts to work, setting the partial pressure proportion of the cleaning fluid flow path or the pressure-bearing value of the first sealing ring according to the use requirement.

And S002, reading the pressure of the mobile phase flow path and sending the pressure to the controller, namely, when the infusion pump runs and the cleaning pump does not run, the pressure detected by a pressure sensor on a pipeline for conveying the mobile phase by the infusion pump. The controller calculates the working pressure of the cleaning liquid in the grading system according to the flowing phase flow path pressure and the set partial pressure proportion or pressure bearing value, and calculates the default flow speed of the cleaning pump through a pressure-flow model.

And S003, starting the cleaning pump at a default flow rate, enabling the cleaning liquid to flow out of the solution bottle, enabling the cleaning liquid to reach a cleaning pump head and a back pressure device of the infusion pump through the cleaning pump, pressurizing the cleaning liquid between the cleaning pump and the back pressure device, cleaning the plunger rod under the condition of certain pressure, and enabling the cleaning liquid to flow into the waste liquid bottle through the back pressure device.

And S004, reading the actual pressure of the cleaning liquid flow path by the pressure sensor and sending the actual pressure to the controller, wherein the actual pressure of the cleaning liquid flow path is often inconsistent with the set working pressure.

And S005, judging whether the actual pressure of the cleaning liquid flow path is within a set working pressure threshold range by the controller, if so, keeping the working flow rate of the cleaning pump unchanged, and if not, calculating the proper working flow rate by the controller and controlling the adjustment of the cleaning pump. The working pressure has an upper critical value range and a lower critical value range, the actual pressure is in the critical value range, the cleaning pump works normally, if the working pressure is lower than the minimum critical value, the controller controls the cleaning pump to increase the flow rate to increase the actual pressure, and if the working pressure is higher than the maximum critical value, the controller controls the cleaning pump to decrease the flow rate to decrease the actual pressure.

The pressure of the cleaning liquid is increased to overcome the surface tension of the liquid, the cleaning liquid enters a gap between the plunger rod and the cleaning pump head, and is fully contacted with the buffer salt solution brought out from the surface of the plunger rod, and a diffusion process occurs at the contact liquid level. The essence of the diffusion process is an entropy process, which is manifested in a solution as the transfer of solute molecules from regions of greater concentration to regions of lesser solute concentration. The concentration of the buffer salt in the cleaning solution is far less than that of the buffer salt in the buffer salt solution. Therefore, the buffer salt in the buffer salt solution diffuses into the washing solution. The concentration of the buffer salt solution of the plunger rod is reduced and does not reach the saturated concentration, and the buffer salt crystal particles can not be separated out, so that the phenomenon that the sealing ring is abraded by crystal grains can not occur, and the purposes of thoroughly cleaning the surface of the plunger rod and prolonging the service life of the sealing ring can be achieved.

For the first sealing ring, on one hand, the pressure difference of deformation generated in the prior art is between the pressure of a mobile phase system and the atmospheric pressure, the pressure difference is large, the deformation of the first sealing ring is also large, on the other hand, gradient sample introduction is predominant for a chromatographic system, the mobile phase composition is changed during the gradient sample introduction, the system pressure can also be changed along with the change of the mobile phase composition, and at the moment, the deformation of the constant-pressure cleaned first sealing ring in the prior art is changed along with the change of the mobile phase composition. Therefore, pressure-variable cleaning is needed, the pressure difference generated at present is between the pressure of the mobile phase system and the pressure of the cleaning liquid, so that the pressure difference at two ends of the first sealing ring is always stabilized at a similar value, the pressure difference is reduced, the deformation change is reduced, the alternating fatigue is reduced, the service life is prolonged, and the controllable pressure of the cleaning liquid is beneficial to cleaning of an HPLC (high performance liquid chromatography) system and an UHPLC (ultra high performance programmable logic controller) system under a gradient.

Preferably, after the grading system works, the pressure of the mobile phase flow path is read from time to time and sent to the controller, and the controller calculates the corresponding working pressure of the cleaning pump according to the pressure of the mobile phase flow path and controls the cleaning pump to adjust. The pressure difference at the two ends of the first sealing ring is ensured to be always stabilized at a similar value, and the deformation of the first sealing ring is kept stable.

Preferably, in step S003, the controller controls the bypass valve to select whether the cleaning liquid flows into the waste liquid bottle or the solution bottle, and the cleaning liquid is returned to the reflux circulation mode depending on the condition of the cleaning liquid, for example, when the cleaning liquid in the solution bottle is insufficient.

The invention has the beneficial effects that:

1. the pressure of the cleaning liquid is accurately controlled, the system pressure is shared, and the problem of poor repeatability caused by trace leakage of a sealing ring under high pressure in a UHPLC system is solved.

2. And the pressure difference between the two ends of the first sealing ring is fixed, so that the alternating fatigue of the sealing ring caused by periodic deformation is reduced, and the service life is prolonged.

3. Adopt high-pressure cleaning mode cooperation washing chamber design, through the mode that increases washing liquid pressure and washing liquid and plunger rod area of contact, improve solvent replacement efficiency, make the washing liquid change enter into the plunger rod and wash the gap between the pump head in, fully wash plunger rod surface buffer solution, prevent that buffer salt crystallization particle from appearing, protection plunger rod and sealing washer surface, extension transfer pump system life.

Drawings

FIG. 1 is a schematic diagram of the hierarchical system of the present invention;

FIG. 2 is a perspective view of an infusion pump in the staging system of the present invention;

FIG. 3 is a partial cross-sectional view of an infusion pump in the staging system of the present invention;

FIG. 4 is a schematic flow chart of a hierarchical system control method of the present invention;

FIG. 5 is a schematic flow chart of the cleaning solution of the present invention.

The main elements in the figures are symbolically illustrated: 10. the device comprises a solution bottle, 20, a cleaning pump, 30, an infusion pump, 31, a pump head, 31.1, a joint, 31.2, a one-way valve, 32, a pump head seat, 33, a plunger rod, 34, a spring seat, 35, a compression spring, 36, a cleaning pump head, 36.1, a cleaning cavity, 36.2, a cleaning joint, 37, a first sealing ring, 38, a second sealing ring, 39, a guide ring, 310, a screw cap, 311, a locking ring, 40, a backpressure device, 50, a pressure sensor, 60, a waste liquid bottle, 70, a controller, 80 and a bypass valve.

Detailed Description

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