A high-precision liquid management system

Abstract

This invention relates to a high-precision liquid management system, comprising a pressure control unit, a liquid addition valve group, a liquid replenishment valve group, an operating bottle group, a liquid replenishment bottle group, and a liquid preparation bottle group. Each operating bottle in the operating bottle group corresponds one-to-one with a liquid addition valve in the liquid addition valve group and a liquid replenishment valve in the liquid replenishment valve group. The operating bottle is connected to the corresponding liquid addition valve and the liquid preparation bottle in sequence via a liquid addition pipe for inputting liquid into the liquid preparation bottle. The operating bottle is connected to the corresponding liquid replenishment valve and the liquid replenishment bottle in sequence via a liquid replenishment pipe for extracting liquid from the liquid replenishment bottle and replenishing it into the operating bottle. The pressure control unit includes a positive pressure air path and a negative pressure air path. Both air paths are connected to each operating bottle via solenoid valves, providing a constant positive or negative pressure to the operating bottle. When there is a constant positive pressure in the operating bottle, liquid can be quantitatively input into the liquid preparation bottle; when there is a constant negative pressure in the operating bottle, liquid can be quantitatively extracted from the liquid replenishment bottle and replenished into the operating bottle.

Description

Technical Field

[0001] This invention belongs to the technical field of laboratory liquid dispensing and adding devices, and specifically relates to a high-precision liquid management system. Background Technology

[0002] With the rapid development of technologies in fields such as biology, medicine, and chemistry, the demand for high-throughput and high-precision liquid handling has surged. Traditional manual pipetting operations are inefficient and have a high error rate, making it difficult to meet the requirements of standardization and repeatability. Therefore, the field of high-precision liquid management in laboratories is facing challenges. At present, high-precision liquid dispensing technologies are mainly divided into two categories: contact pipetting and non-contact pipetting. Contact pipetting is driven by a piston and relies on the contact between the pipette tip and the liquid surface, and is suitable for liquid sampling of more than 1 μL. Among non-contact pipetting, (1) piezoelectric jetting technology, such as the Suzhou Institute of Biomedical Engineering and Technology of the Chinese Academy of Sciences, has achieved 0.1 μL-level dispensing (error ±3%), which is used for single-cell sorting; (2) aerosol jetting technology, such as the nL-level technology developed by Shenzhen Microfluidics Technology, but its stability is insufficient (batch-to-batch CV>5%). Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a high-precision liquid management system, comprising a pneumatic control unit, a liquid filling valve group, a liquid replenishment valve group, an operating bottle group, a liquid replenishment bottle group, and a liquid preparation bottle group. Each operating bottle in the operating bottle group corresponds one-to-one with a liquid filling valve in the liquid filling valve group and a liquid replenishment valve in the liquid replenishment valve group. The operating bottle is connected to the corresponding liquid filling valve and the liquid preparation bottle in sequence via a liquid filling pipe for inputting liquid into the liquid preparation bottle. The operating bottle is connected to the corresponding liquid replenishment valve and the liquid replenishment bottle in sequence via a liquid replenishment pipe for drawing liquid from the liquid replenishment bottle and replenishing it into the operating bottle.

[0004] The pneumatic control unit includes a positive pressure pneumatic circuit and a negative pressure pneumatic circuit. Both pneumatic circuits are connected to each operating bottle through a solenoid valve, providing a constant positive or negative pressure to the operating bottle. When there is a constant positive pressure in the operating bottle, liquid can be quantitatively introduced into the dispensing bottle; when there is a constant negative pressure in the operating bottle, liquid can be quantitatively drawn from the replenishment bottle and added to the operating bottle.

[0005] Optionally, the operating bottle group includes several operating bottles, and two liquid level sensors are correspondingly provided on the outer side wall of each operating bottle. A lower limit liquid level sensor is provided at the bottom of the operating bottle, and an upper limit liquid level sensor is provided at the top of the operating bottle, which are used to monitor the liquid level in the operating bottle in real time.

[0006] Optionally, the replenishment bottle group includes several replenishment bottles, each containing different types of liquids, which can provide multiple liquids to the operation bottle group and the dispensing bottle group to meet different dispensing needs and prepare different solutions; the replenishment pipe on the upstream side of the replenishment valve can be connected to different replenishment bottles, so that the operation bottle can receive replenishment from different replenishment bottles.

[0007] Alternatively, one of the replenishment bottles contains cleaning fluid, and the process of the cleaning fluid flowing through the replenishment tube, operation bottle, addition tube, and dispensing bottle is the process of cleaning each component.

[0008] Optionally, the liquid filling valve group includes several liquid filling valves, each corresponding to an operating bottle and a liquid filling tube. The liquid filling valve can control the opening and closing of the corresponding liquid filling tube to realize the supply of liquid from the operating bottle to the liquid preparation bottle.

[0009] The replenishment valve assembly includes several replenishment valves, each corresponding to an operating bottle and a replenishment tube. The replenishment valve can control the opening and closing of the corresponding replenishment tube, enabling the replenishment bottle to supply liquid to the operating bottle.

[0010] Optionally, the air pressure control unit further includes a vacuum regulating valve, an electro-proportional valve, and a micro flow meter, with each solenoid valve and micro flow meter corresponding to a specific operating bottle; the upstream end of the positive pressure air path is connected to an air supply device, and the downstream end is connected to an electro-proportional valve, and then it is evenly divided into several positive air paths, each of which is connected to a corresponding solenoid valve; the upstream end of the negative pressure air path is connected to a vacuum pump or a vacuum pump, and the downstream end is connected to a vacuum regulating valve, and then it is evenly divided into several negative air paths, each of which is connected to a corresponding solenoid valve.

[0011] The outlet of the solenoid valve is connected in sequence to the corresponding miniature flow meter and the operating bottle through the main air circuit, which can provide a stable positive or negative air pressure to the operating bottle.

[0012] Alternatively, the solenoid valve may be a three-way solenoid valve, with one inlet connected to the positive gas distribution path and the other inlet connected to the negative gas distribution path.

[0013] Optionally, the liquid adding tube is connected to a liquid measuring device, which includes a support and a measuring cylinder. The measuring cylinder is an inverted cone, larger at the top and smaller at the bottom. The top of the measuring cylinder has an inlet, and the center of the bottom has an outlet. The outlet has a switchable valve, which is used to receive the liquid from the liquid adding tube and to discharge the liquid in the measuring cylinder into the dispensing bottle.

[0014] The support is equipped with at least two laser emitters arranged side by side for detecting the liquid level in the volumetric cylinder; the top of the volumetric cylinder is mounted on the support to keep the top surface of the volumetric cylinder horizontal.

[0015] Further optionally, the upper part of the bracket is provided with a support ring, the inside of the support ring is hollowed out, the outer wall of the top of the measuring cylinder is placed on the support ring, and the other part of the measuring cylinder passes through the support ring and is suspended in the air;

[0016] Below the support ring are two horizontal beams, which are parallel to each other and of the same height. The two ends of the beams are detachably connected to the two columns of the support. The height of the beams is adjustable. Several laser emitters are installed on one beam, and the laser emitters are evenly arranged along the length of the corresponding beam. Several laser receivers are installed on the other beam, and the positions of the laser receivers correspond one-to-one with the laser emitters.

[0017] Optionally, the inlet is located near the edge of the top surface of the volumetric cylinder, allowing liquid to be input into one side of the cylinder. The diameter of the top surface where the inlet and the center of the top surface of the volumetric cylinder are located is the central axis. The crossbeam is parallel to the central axis, so that the monitoring points of several laser emitters are set along the axis directly below the central axis. Attached Figure Description

[0018] Figure 1 A schematic diagram of a high-precision liquid management system (I);

[0019] Figure 2 Schematic diagram (II) of the high-precision liquid management system;

[0020] Figure 3 A schematic diagram (III) of the high-precision liquid management system is shown.

[0021] Figure 4 Schematic diagram of a volumetric liquid meter (I);

[0022] Figure 5 Schematic diagram of a volumetric liquid meter (II).

[0023] In the attached diagram, 1-operation bottle, 2-liquid filling valve, 3-liquid replenishment valve, 4-liquid filling pipe, 5-liquid replenishment pipe, 7-liquid replenishment bottle, 8-lower limit liquid level sensor, 9-upper limit liquid level sensor, 10-vacuum regulating valve, 11-electric proportional valve, 12-micro flow meter, 13-solenoid valve, 14-liquid measuring cylinder, 15-positive pressure air path, 16-inlet, 17-laser emitter, 18-negative pressure air path, 19-crossbeam. Detailed Implementation

[0024] This embodiment provides a high-precision liquid management system, such as... Figures 1-5 As shown, the system includes a pneumatic control unit, a liquid filling valve group, a liquid replenishment valve group, an operating bottle group, a liquid replenishment bottle group, and a liquid preparation bottle group. Each operating bottle 1 in the operating bottle group corresponds one-to-one with a liquid filling valve 2 in the liquid filling valve group and a liquid replenishment valve 3 in the liquid replenishment valve group. The operating bottle 1 is connected to the corresponding liquid filling valve 2 and the liquid preparation bottle in sequence through a liquid filling pipe 4, which is used to input liquid into the liquid preparation bottle. The operating bottle 1 is connected to the corresponding liquid replenishment valve 3 and the liquid replenishment bottle 7 in sequence through a liquid replenishment pipe 5, which is used to draw liquid from the liquid replenishment bottle 7 to replenish the operating bottle 1.

[0025] The air pressure control unit includes a positive pressure air path and a negative pressure air path. Both air paths are connected to each operating bottle 1 through a solenoid valve 13, providing a constant positive or negative air pressure to the operating bottle 1. When there is a constant positive pressure in the operating bottle 1, liquid can be quantitatively input into the liquid preparation bottle; when there is a constant negative pressure in the operating bottle 1, liquid can be quantitatively drawn from the replenishment bottle 7 and added to the operating bottle 1.

[0026] The operating bottle group 1 includes several operating bottles 1. Each operating bottle 1 has two liquid level sensors installed on its outer side wall. The lower part of the operating bottle 1 is provided with a lower limit liquid level sensor 8, and the upper part of the operating bottle 1 is provided with an upper limit liquid level sensor 9, which are used to monitor the liquid level in the operating bottle 1 in real time.

[0027] If the liquid level in operating bottle 1 is lower than the lower limit liquid level sensor 8, it means that there is not enough liquid in the bottle and liquid needs to be drawn from replenishment bottle 7 to replenish operating bottle 1. When replenishing operating bottle 1, if the liquid level reaches the upper limit liquid level sensor 9, replenishment will stop and liquid can continue to be supplied to the dispensing bottle.

[0028] The solution preparation bottle assembly includes several solution preparation bottles for receiving a fixed amount of liquid from the operation bottle 1 to complete the liquid dispensing operation; the dispensing tube 4 downstream of the dispensing valve 2 can be connected to different solution preparation bottles to provide a fixed amount of liquid to one or more solution preparation bottles. The solution preparation bottles can be various types of containers used in the biochemical field for holding liquids, such as volumetric flasks, sample tubes, test tubes, etc.

[0029] The replenishment bottle group 7 includes several replenishment bottles 7, each containing different types of liquids, which can provide multiple liquids to the operation bottle group 1 and the dispensing bottle group to meet different dispensing needs and prepare different solutions; the replenishment pipe 5 on the upstream side of the replenishment valve 3 can be connected to different replenishment bottles 7, so that the operation bottle 1 can receive replenishment from different replenishment bottles 7.

[0030] One of the replenishment bottles 7 contains cleaning fluid. The process of the cleaning fluid flowing through the replenishment tube 5, operation bottle 1, addition tube 4, and dispensing bottle is the process of cleaning each component.

[0031] The liquid addition valve group 2 includes several liquid addition valves 2, each corresponding to an operating bottle 1 and a liquid addition tube 4. The liquid addition valve 2 can control the opening and closing of the corresponding liquid addition tube 4, so as to realize the liquid supply from the operating bottle 1 to the liquid preparation bottle.

[0032] The replenishment valve group 3 includes several replenishment valves 3, each corresponding to the operation bottle 1 and the replenishment tube 5. The replenishment valve 3 can control the opening and closing of the corresponding replenishment tube 5, so as to realize the replenishment bottle 7 to supply liquid to the operation bottle 1.

[0033] The air pressure control unit also includes a vacuum regulating valve 10, an electro-proportional valve 11, and a micro flow meter 12. The solenoid valve 13 and the micro flow meter 12 correspond one-to-one with the operating bottle 1. The upstream end of the positive pressure air path 15 is connected to the air supply device, and the downstream end is connected to the electro-proportional valve 11. Then it is evenly divided into several positive air paths, and each positive air path is connected to the corresponding solenoid valve 13. The upstream end of the negative pressure air path 18 is connected to the air pump or vacuum pump, and the downstream end is connected to the vacuum regulating valve 10. Then it is evenly divided into several negative air paths, and each negative air path is connected to the corresponding solenoid valve 13.

[0034] The outlet of the solenoid valve 13 is connected in sequence to the corresponding micro flow meter 12 and the operating bottle 1 through the main air circuit, which can provide stable positive or negative air pressure to the operating bottle 1.

[0035] The solenoid valve 13 is a three-way solenoid valve 13, with one inlet connected to the positive gas distribution path and the other inlet connected to the negative gas distribution path.

[0036] The gas supply device can be a compressed air cylinder or an inert gas cylinder, which can provide gas to the operating cylinder 1. The operating cylinder 1 can be provided with a constant positive or negative pressure through the main gas circuit.

[0037] This invention abandons traditional contact pipetting and belongs to non-contact pipetting. Compared with piezoelectric jetting and aerosol jetting, this invention selects a cheap, readily available, and easy-to-control gas (pressure) control method, which is lower in cost, easier to control, and simpler to operate. This invention provides a constant positive pressure to the operating bottle 1, forcing the liquid in the operating bottle 1 to flow into the dispensing bottle. That is, the flow rate in the dispensing tube 4 is constant. With the length of the dispensing tube 4 remaining unchanged, the volume of liquid added can be controlled by controlling the opening time of the dispensing tube 4 through the dispensing valve 2. Similarly, providing a constant negative pressure to the operating bottle 1 draws the liquid from the replenishment bottle 7 into the operating bottle 1. That is, the flow rate in the replenishment tube 5 is constant. With the length of the replenishment tube 5 remaining unchanged, the volume of replenishment can be controlled by controlling the opening time of the replenishment tube 5 through the replenishment valve 3.

[0038] Specifically, the electro-proportional valve can precisely regulate the pressure at its output end, ensuring that the pressure reaching the operating bottle remains constant. The pressure regulation range of the electro-proportional valve is 0-0.5 MPa, with a pressure regulation repeatability within ±0.5% and a gas pressure regulation sensitivity within ±0.2%. The positive pressure gas path, through the electro-proportional valve 11, divides the positive pressure into several equal parts, each supplying pressure to the corresponding operating bottle 1. The positive gas branch paths are connected to the inlet of the corresponding solenoid valve 13, and the gas is output from the outlet of the solenoid valve 13 to the main gas path, then passes through the corresponding micro flow meter 12. The micro flow meter 12 remains open during system operation, monitoring the flow rate of the gas in real time to determine whether the positive or negative pressure is constant, preventing pressure changes due to gas leaks or other reasons from causing a decrease in liquid dispensing accuracy. The main gas path, through an adapter, is finally inserted into the corresponding operating bottle 1, providing a constant positive pressure to force the liquid out of the bottle.

[0039] The negative pressure gas path regulates the negative pressure provided by the vacuum regulating valve 10. The negative pressure is divided into several parts through several negative gas distribution paths. Each negative gas distribution path is connected to another inlet of the corresponding solenoid valve 13, and then connected to the main gas path to draw negative pressure into the corresponding operation bottle 1. The micro flow meter 12 also monitors this. The three-way solenoid valve 13 switches which inlet to use according to the program instructions of the control device, thereby controlling whether the output gas is negative or positive pressure, thus enabling the operation bottle 1 to be in the replenishment or addition state.

[0040] In this invention, the gas pressure within each operating bottle 1 is a stable and controllable pressure environment. Each operating bottle 1 is connected to a liquid addition pipe 4 and a liquid replenishment pipe 5. The liquid addition pipe 4 is connected to a dispensing bottle via a liquid addition valve 2, and the liquid replenishment pipe 5 is connected to a replenishing bottle 7 via a liquid replenishment valve 3. When a stable positive pressure gas is introduced into the operating bottle 1, the system is in a ready-to-add liquid state. The liquid addition valve 2 connects the corresponding operating bottle 1 to the dispensing bottle, and the liquid in the operating bottle 1 is discharged into the corresponding dispensing bottle through the liquid addition pipe 4. Under the stable pressure environment of the operating bottle 1, the liquid discharged per unit time is also a constant value due to the positive pressure. The precise addition of liquid is achieved by switching the liquid addition valve 2 (i.e., the high-precision liquid switching valve) on and off. The liquid addition accuracy in this mode can be controlled within <1% (within 1 ml per addition), which can realize most laboratory liquid automation application scenarios.

[0041] When the signal from the lower limit level sensor 8 next to operating bottle 1 disappears, it indicates that the liquid level in the bottle has dropped below the minimum warning level, triggering the system to automatically replenish the liquid. Solenoid valve 13 switches from positive pressure to vacuum pressure, creating a micro-vacuum environment inside operating bottle 1. The corresponding replenishment valve 3 for operating bottle 1 is activated, and liquid from replenishment bottle 7 is introduced into operating bottle 1 through replenishment pipe 5. As the liquid level in operating bottle 1 rises, it reaches the position of the upper limit level sensor 9, activating the sensor signal and stopping the replenishment process. Solenoid valve 13 switches back to the positive pressure inlet, replenishment valve 3 closes, and the system returns to the ready-to-add state.

[0042] After multiple liquid additions or when changing to different types of sample solutions, the system's tubing and operating bottle 1 need to be cleaned. The cleaning procedure is initiated, and the replenishment valve 3 of the replenishment bottle 7 containing the cleaning solution is opened. The solenoid valve 13 repeatedly switches between positive and negative pressure interfaces, intermittently creating a positive or negative pressure environment inside operating bottle 1. Under negative pressure, the cleaning solution enters operating bottle 1 from replenishment bottle 7; under positive pressure, the cleaning solution exits from operating bottle 1. After multiple operations, the internal cleaning of operating bottle 1 is completed.

[0043] Depending on different liquid addition requirements, the liquid addition accuracy can be adjusted by replacing the liquid addition tube 4 with one of different diameters. For example, for micro-volume, high-precision liquid addition requirements, a liquid addition path with a smaller inner diameter can be used to achieve smaller liquid addition volumes per unit time, thereby meeting the requirement for higher liquid addition accuracy. The control of the above-mentioned functions and operations of this invention can be achieved using an existing PLC controller.

[0044] During the experiment, the inventors discovered that, due to the possibility of a very small amount of dissolved gas in the liquid within the operating bottle 1 when positive pressure is applied, the gas first dissolves in the liquid when positive pressure is introduced into the operating bottle 1. Only after the liquid is saturated with the gas does it exert its pressurizing effect, thus causing a slight error during liquid addition. To address this problem, the present invention proposes the following solution.

[0045] The liquid addition tube 4 is connected to the liquid measuring device, which includes a support and a liquid measuring cylinder 14. The liquid measuring cylinder 14 is an inverted cone, larger at the top and smaller at the bottom. The top of the liquid measuring cylinder 14 is provided with an inlet 16, and the center of the bottom is provided with an outlet. The outlet is provided with a switchable valve, which is used to receive the liquid from the liquid addition tube 4 and to discharge the liquid in the liquid measuring cylinder 14 into the liquid preparation bottle.

[0046] The support is equipped with at least two laser emitters 17 arranged side by side for detecting the liquid level in the measuring cylinder 14; the top of the measuring cylinder 14 is mounted on the support to keep the top surface of the measuring cylinder 14 horizontal.

[0047] Further optionally, the upper part of the bracket is provided with a support ring, the inside of the support ring is hollow, the outer wall of the top of the measuring cylinder 14 is placed on the support ring, and the other parts of the measuring cylinder 14 pass through the support ring and are suspended in the air;

[0048] Below the support ring are two parallel crossbeams 19, each at the same height. The two ends of each crossbeam are detachably connected to two uprights of the support frame. The height of the crossbeams 19 is adjustable. One crossbeam has several laser emitters 17 evenly distributed along the length of the corresponding crossbeam. The other crossbeam has several laser receivers, each corresponding to one of the laser emitters. A measuring cylinder is positioned between the two crossbeams.

[0049] The support can be a standard support structure, such as a support ring supporting the upper part of four columns, with the four columns forming a square.

[0050] The inlet 16 is located near the edge of the top surface of the measuring cylinder 14, allowing liquid to be input into one side of the measuring cylinder 14. The diameter of the top surface where the center of the top surface of the measuring cylinder 14 and the inlet 16 are located is the central axis. The crossbeam 19 is parallel to the central axis, so that the monitoring points of several laser emitters 17 are set along the axis directly below the central axis.

[0051] The measuring cylinder 14 of this invention receives the liquid delivered by the liquid filling pipe 4, and accurately measures the volume of the incoming liquid again within the measuring cylinder 14 before inputting it into the dispensing bottle. Specifically, the measuring cylinder 14 is vertically arranged, and both the top surface of the measuring cylinder 14 and the crossbeam 19 are horizontally arranged. Since the measuring cylinder 14 is an inverted cone, adjusting the liquid volume within the measuring cylinder 14 only requires controlling the liquid level height within the measuring cylinder 14. The height of the crossbeam 19 is adjusted according to the volume of liquid to be collected, ensuring that the monitoring points of the laser emitter and laser receiver are both at the target liquid level. The liquid filling pipe 4 is connected to the inlet 16, allowing liquid to enter from one side edge of the measuring cylinder 14. As the liquid level rises within the measuring cylinder 14, at a microscopic level, the liquid level on the side closer to the inlet 16 rises first, followed by the side farther from the inlet 16. Once the liquid is evenly distributed within the measuring cylinder 14, the liquid level within the measuring cylinder 14 will reach a uniform horizontal height. The liquid addition tube 4 can add liquid to the inlet 16 in a drip manner, that is, add it drop by drop, allowing time for the liquid level in the measuring cylinder 14 to become uniform.

[0052] When the liquid level in the measuring cylinder 14 is about to reach the target level, but has not yet reached it, the liquid adding tube 4 adds a drop of liquid into the inlet 16. The laser emitted by the laser emitter near the inlet 16 is affected by the liquid surface, and the corresponding laser receiver detects the target liquid level, but other laser receivers do not detect the laser change. Then the liquid level in the measuring cylinder 14 becomes uniform. The pair of laser emitters that first detected the target liquid level can no longer detect the liquid level, and liquid should continue to be added. After adding one drop, the pair of laser emitters near the inlet 16 detect the target liquid level first, but other laser emitters do not detect it. Subsequently, the liquid level in the measuring cylinder 14 becomes uniform, and the overall liquid level reaches the target liquid level. All laser emitters detect the target liquid level. At this time, the liquid adding valve 2 is closed, liquid adding stops, and the target liquid volume is measured in the measuring cylinder 14. The valve at the outlet of the measuring cylinder 14 is opened, and the internal liquid flows into the mixing bottle. Then, air is blown into the measuring cylinder 14 through the inlet 16 to blow away the liquid droplets hanging on the inner wall and discharge all the liquid in the measuring cylinder 14.

[0053] The results of the liquid addition experiment for the above liquid management system are shown in the table below:

[0054] Table 1 Results of the liquid addition experiment (I)

[0055]

[0056] Repeatability is determined by performing 50 repeated experiments for each nominal capacity, and calculating the average and standard deviation of the actual capacity for each experiment. Repeatability accuracy (%) = (standard deviation / average) × 100%.

[0057] In the table above, the actual capacity and relative capacity error corresponding to each nominal capacity are the results of one experiment. The repeatability precision corresponding to each nominal capacity is the result of 50 experiments, including the one experiment mentioned above. Due to the large amount of data, it is not fully displayed here.

[0058] As can be seen from the table above, the liquid management system provided by this invention has high liquid addition accuracy and good repeatability, reaching the level required for industrial applications.

Claims

1. A high-precision liquid management system, characterized in that, It includes a pneumatic control unit, a liquid adding valve group, a liquid replenishing valve group, an operating bottle group, a liquid replenishing bottle group, and a liquid dispensing bottle group. Each operating bottle in the operating bottle group corresponds one-to-one with a liquid adding valve in the liquid adding valve group and a liquid replenishing valve in the liquid replenishing valve group. The operating bottle is connected to the corresponding liquid adding valve and the liquid dispensing bottle in sequence through a liquid adding pipe for inputting liquid into the liquid dispensing bottle. The operating bottle is connected to the corresponding liquid replenishing valve and the liquid replenishing bottle in sequence through a liquid replenishing pipe for drawing liquid from the liquid replenishing bottle to replenish the operating bottle. The pneumatic control unit includes a positive pressure pneumatic circuit and a negative pressure pneumatic circuit. Both pneumatic circuits are connected to each operating bottle through a solenoid valve, providing a constant positive or negative pressure to the operating bottle. When there is a constant positive pressure in the operating bottle, liquid can be quantitatively introduced into the dispensing bottle; when there is a constant negative pressure in the operating bottle, liquid can be quantitatively drawn from the replenishment bottle and added to the operating bottle. The air pressure control unit also includes a vacuum regulating valve, an electro-proportional valve, and a micro flow meter. The solenoid valve and the micro flow meter correspond one-to-one with the operating bottle. The upstream end of the positive pressure air path is connected to the air supply device, and the downstream end is connected to the electro-proportional valve. Then it is evenly divided into several positive air paths, and each positive air path is connected to the corresponding solenoid valve. The upstream end of the negative pressure air path is connected to the air pump, and the downstream end is connected to the vacuum regulating valve. Then it is evenly divided into several negative air paths, and each negative air path is connected to the corresponding solenoid valve. The outlet of the solenoid valve is connected to the corresponding miniature flow meter and the operating bottle in sequence through the main air circuit, which can provide a stable positive or negative air pressure to the operating bottle; The liquid addition tube is connected to the liquid measuring device, which includes a support and a liquid measuring cylinder. The liquid measuring cylinder is an inverted cone, larger at the top and smaller at the bottom. The top of the liquid measuring cylinder has an inlet, and the center of the bottom has an outlet. The outlet has a switchable valve, which is used to receive the liquid from the liquid addition tube and to discharge the liquid in the liquid measuring cylinder into the dispensing bottle. The support is equipped with at least two laser emitters arranged side by side for detecting the liquid level in the volumetric cylinder; the top of the volumetric cylinder is mounted on the support to keep the top surface of the volumetric cylinder horizontal. The upper part of the bracket is provided with a support ring, the inside of which is hollowed out. The outer wall of the top of the measuring cylinder is placed on the support ring, and the other part of the measuring cylinder passes through the support ring and is suspended in the air. Below the support ring are two horizontal beams, which are parallel to each other and of the same height. The two ends of the beams are detachably connected to the two columns of the support. The height of the beams is adjustable. Several laser emitters are installed on one beam, and the laser emitters are evenly arranged along the length of the corresponding beam. Several laser receivers are installed on the other beam, and the positions of the laser receivers correspond one-to-one with the laser emitters.

2. The high-precision liquid management system according to claim 1, characterized in that, The operating bottle group includes several operating bottles. Each operating bottle has two liquid level sensors installed on its outer side wall. The lower part of the operating bottle is equipped with a lower limit liquid level sensor, and the upper part of the operating bottle is equipped with an upper limit liquid level sensor, which are used to monitor the liquid level in the operating bottle in real time.

3. The high-precision liquid management system according to claim 1, characterized in that, The replenishment bottle group includes several replenishment bottles, each containing different types of liquids, which can provide multiple liquids to the operation bottle group and the dispensing bottle group to meet different dispensing needs and prepare different solutions; the replenishment tube on the upstream side of the replenishment valve can be connected to different replenishment bottles, so that the operation bottle can receive replenishment from different replenishment bottles.

4. The high-precision liquid management system according to claim 3, characterized in that, One of the replenishment bottles contains cleaning fluid. The process of the cleaning fluid flowing through the replenishment tube, operation bottle, addition tube, and dispensing bottle is the process of cleaning each component.

5. The high-precision liquid management system according to claim 1, characterized in that, The liquid filling valve group includes several liquid filling valves, each corresponding to an operating bottle and a liquid filling tube. The liquid filling valve can control the opening and closing of the corresponding liquid filling tube to realize the supply of liquid from the operating bottle to the liquid preparation bottle. The replenishment valve assembly includes several replenishment valves, each corresponding to an operating bottle and a replenishment tube. The replenishment valve can control the opening and closing of the corresponding replenishment tube, enabling the replenishment bottle to supply liquid to the operating bottle.

6. The high-precision liquid management system according to claim 1, characterized in that, The solenoid valve is a three-way solenoid valve, with one inlet connected to the positive gas distribution path and the other inlet connected to the negative gas distribution path.

7. The high-precision liquid management system according to claim 1, characterized in that, The inlet is located near the edge of the top surface of the volumetric cylinder, allowing liquid to be input into one side of the cylinder. The diameter of the top surface where the inlet and the center of the top surface of the volumetric cylinder are located forms the central axis. The crossbeam is parallel to the central axis, so that the monitoring points of several laser emitters are set along the axis directly below the central axis.

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