Liquid adding system of electrochemical luminescence instrument

Abstract

The utility model relates to a liquid adding system of an electrochemical luminescence instrument. The liquid adding system comprises a first liquid storage barrel and a second liquid storage barrel which are used for containing liquid, a first three-way electromagnetic valve and a second three-way electromagnetic valve which are used for switching and controlling the flow direction of a liquid path, and a plunger pump provides power to achieve liquid conveying. The liquid adding system is further provided with a liquid level sensor, a filter, a drip-proof structure and the like, and automatic operation is achieved through control of an upper computer. Through the double-barrel switching design, the problem of air mixing caused by reagent bottle replacement is avoided, and the continuity and stability of the liquid adding process are ensured; the filter can effectively intercept impurities, protect precise parts and reduce the failure rate; the liquid adding precision and the system reliability are improved through the overall design.

Description

Technical Field

[0001] This application relates to the field of electrochemiluminescence immunoassay technology, and in particular to the liquid dispensing system of electrochemiluminescence instruments. Background Technology

[0002] With the development of electrochemiluminescence immunoassay technology, it has been widely used in clinical diagnostics and biological detection. As this technology evolves towards high throughput and automation, more stringent requirements are placed on the stability and continuity of the supporting reagent dispensing system. Against this backdrop, precision dispensing technology based on plunger pumps has gradually become the industry mainstream. It achieves stable delivery of trace amounts of reagents by precisely controlling the pump stroke, becoming a core module to ensure the consistency of test results. To meet the need for continuous dispensing, existing technologies generally adopt single-tank dispensing devices, using a single storage tank in conjunction with pipelines and valves to complete the storage and distribution of reagents.

[0003] In routine operation, this type of single-tank dispensing system uses a plunger pump to draw reagents from the reservoir, which are then delivered to the dispensing needle via a one-way valve and tubing. Its simple structure and low manufacturing cost meet basic requirements in general scenarios. However, as throughput increases and instrument runtime extends, the limitations of single-tank systems become increasingly apparent. For example, when reagents in the reservoir are depleted or need replacement, operators must interrupt the dispensing process and disassemble the tubing, a process that easily introduces air into the system. Air intrusion not only causes instantaneous fluctuations in the dispensing volume but can also affect the repeatability of subsequent test results due to residual air bubbles, posing a serious threat to high-precision analysis. Furthermore, when changing reagent bottles, the frequent friction between the steel needle inserted into the reservoir and the bottle opening can generate metal shavings. If these tiny impurities are not effectively intercepted, they will flow with the liquid into precision components such as the plunger pump or solenoid valve, causing blockages or mechanical wear, ultimately leading to an increased system failure rate. More notably, the single-tank system cannot achieve uninterrupted liquid addition, requiring operators to frequently stop the machine to replace reagent bottles. This not only reduces the instrument's operating efficiency but also causes process interruptions in high-throughput detection, becoming a key bottleneck restricting the improvement of detection throughput.

[0004] The aforementioned problems demonstrate that existing single-tank liquid dispensing systems have significant shortcomings in meeting the demands for high stability and continuity. How to ensure dispensing accuracy while preventing air ingress and contamination, and achieving seamless switching and continuous liquid supply, has become a pressing technical challenge in the field of electrochemiluminescence instruments. Summary of the Invention

[0005] Given the risks of air contamination and low operational efficiency associated with traditional single-tank dispensing devices, it is necessary to provide a dual-tank switching dispensing system.

[0006] A liquid addition system for an electrochemiluminescence instrument, the liquid addition system comprising:

[0007] The first and second liquid storage tanks are used to hold liquids.

[0008] The first three-way solenoid valve has a normally open port connected to the first liquid storage tank via a first liquid supply line, and a normally closed port connected to the second liquid storage tank via a second liquid supply line. The first three-way solenoid valve is used to switch the connection between the first liquid supply line, the second liquid supply line, and the common port of the first three-way solenoid valve.

[0009] The second three-way solenoid valve has its normally open port connected to the sampling needle via a pipeline, and its normally closed port connected to the common port of the first three-way solenoid valve via a pipeline. The common port of the second three-way solenoid valve is connected to the plunger pump via a pipeline. The second three-way solenoid valve is used to control the flow direction of the liquid.

[0010] In one embodiment, a first liquid level sensor is provided on the inner and outer sides of the first liquid storage tank, and a second liquid level sensor is provided on the inner and outer sides of the second liquid storage tank.

[0011] In one embodiment, a suction needle is provided at the connection between the first liquid filling line and the first liquid storage tank, and at the connection between the second liquid filling line and the second liquid storage tank.

[0012] In one embodiment, the tip of the aspirator is provided with a debris-proof structure.

[0013] In one embodiment, a filter is provided on the pipeline between the normally closed port of the second three-way solenoid valve and the common port of the first three-way solenoid valve.

[0014] In one embodiment, the filter is a filter screen.

[0015] In one embodiment, the tip of the sampling needle is provided with an anti-drip structure.

[0016] In one embodiment, the piping of the liquid addition system is made of corrosion-resistant material.

[0017] In one embodiment, the liquid addition system further includes a host computer. Both the first liquid level sensor and the second liquid level sensor are set with alarm liquid levels. The host computer is used to receive signals from the first liquid level sensor or the second liquid level sensor to control the on / off state of the first three-way solenoid valve.

[0018] In one embodiment, the host computer includes an alarm structure that can issue an alarm signal when the liquid level in the first or second liquid storage tank is lower than the alarm level.

[0019] This liquid dispensing system systematically solves the problems of air ingress and low efficiency inherent in traditional single-tank dispensing devices by employing technologies such as automatic switching between dual storage tanks, precise flow control via a three-way solenoid valve, and power coordination with a plunger pump. This system not only improves the stability and throughput of liquid dispensing but also reduces maintenance costs. Attached Figure Description

[0020] Figure 1 A schematic diagram illustrating the working principle of a liquid dispensing system provided in this application.

[0021] The reference numerals in the detailed embodiments are as follows:

[0022] 1. First storage tank; 2. Second storage tank; 3. First three-way solenoid valve; 4. Filter; 5. Second three-way solenoid valve; 6. Plunger pump; 7. Sampling needle; 8. First liquid level sensor; 9. Second liquid level sensor; 10. Aspiration needle; 11. First liquid addition line; 12. Second liquid addition line;

[0023] 31. Common port of the first three-way solenoid valve; 32. Normally open port of the first three-way solenoid valve; 33. Normally closed port of the first three-way solenoid valve;

[0024] 51. Common port of the second and third-way solenoid valve; 52. Normally open port of the second and third-way solenoid valve; 53. Normally closed port of the second and third-way solenoid valve. Detailed Implementation

[0025] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0026] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0027] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0028] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0029] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0030] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0031] See Figure 1 , Figure 1 The diagram shows the working principle of the liquid addition system in one embodiment of this application. The liquid addition system of the electrochemiluminescence instrument provided in one embodiment of this application includes a first liquid storage tank 1, a second liquid storage tank 2, a first three-way solenoid valve 3, a second three-way solenoid valve 5, a first liquid addition line 11, a second liquid addition line 12, a sampling needle 7, and a plunger pump 6.

[0032] In the liquid dispensing system of this application, the first liquid storage tank 1 and the second liquid storage tank 2 are used to hold liquid reagents. The normally open port 32 of the first three-way solenoid valve is connected to the first liquid storage tank 1 through the first liquid dispensing line 11, and the normally closed port 33 of the first three-way solenoid valve is connected to the second liquid storage tank 2 through the second liquid dispensing line 12. The first three-way solenoid valve 3 is used to switch the connection between the first liquid dispensing line 11 and the second liquid dispensing line 12 and the common port 31 of the first three-way solenoid valve. The normally open port 52 of the second three-way solenoid valve is connected to the sampling needle 7 through a line, and the normally closed port 53 of the second three-way solenoid valve is connected to the common port 31 of the first three-way solenoid valve through a line. The common port 51 of the second three-way solenoid valve is connected to the plunger pump 6 through a line. The second three-way solenoid valve 5 is used to control the flow direction of the liquid.

[0033] The first liquid storage tank 1 and the second liquid storage tank 2 are respectively connected to the normally open port 32 and the normally closed port 33 of the first three-way solenoid valve through the first liquid addition line 11 and the second liquid addition line 12. The common port 31 of the first three-way solenoid valve is connected to the normally closed port 53 of the second three-way solenoid valve through a pipeline. The common port 51 of the second three-way solenoid valve is connected to the plunger pump 6, and the normally open port 52 of the second three-way solenoid valve is connected to the sampling needle 7.

[0034] The dual-tank switching liquid delivery system for the electrochemiluminescence instrument provided in this application achieves continuous and stable liquid delivery through the coordinated operation of two liquid storage tanks, precise flow control via a three-way solenoid valve, and power drive by a plunger pump. The specific operating method is as follows:

[0035] The dual-tank switching liquid addition system of the electrochemiluminescence instrument has a first working mode: When the plunger pump 6 draws liquid from the first storage tank 1, the first three-way solenoid valve 3 is de-energized, and the common port 31 of the first three-way solenoid valve is connected to the normally open port 32 of the first three-way solenoid valve. Liquid flows out from the first storage tank 1 and flows through the normally open port 32 of the first three-way solenoid valve from the first liquid addition pipeline 11. The second three-way solenoid valve 5 is energized, and the common port 51 of the second three-way solenoid valve is connected to the normally closed port 53 of the second three-way solenoid valve. Liquid flows from the common port 31 of the first three-way solenoid valve to the normally closed port 53 of the second three-way solenoid valve, and finally enters the plunger pump 6 through the common port 51 of the second three-way solenoid valve, completing the liquid drawing. When the plunger pump 6 discharges liquid, the second three-way solenoid valve 5 is de-energized. The common port 51 of the second three-way solenoid valve is connected to the normal opening 52 of the second three-way solenoid valve. The liquid flows out of the pipeline through the plunger pump 6, through the common port 51 of the second three-way solenoid valve to the normal opening 52 of the second three-way solenoid valve, and finally out of the sampling needle 7 through the pipeline.

[0036] The dual-tank switching liquid supply system of the electrochemiluminescence instrument also has a second working mode: The first three-way solenoid valve 3 is energized. In this mode, the common port 31 of the first three-way solenoid valve is connected to the normally closed port 33, switching the liquid supply from the first storage tank 1 to the second storage tank 2, ensuring seamless liquid supply and effectively preventing air contamination. When the first three-way solenoid valve 3 is energized and the second storage tank 2 is supplying liquid, the specific working method is as follows: When the plunger pump 6 draws liquid from the second storage tank 2, the first three-way solenoid valve 3 is energized, and the common port 31 of the first three-way solenoid valve is connected to the normally closed port 33. Liquid flows out from the second storage tank 2 and flows through the normally closed port 33 of the first three-way solenoid valve from the second liquid supply pipeline 12. When the second three-way solenoid valve 5 is energized, its common port 51 is connected to its normally closed port 53. Liquid flows from the common port 31 of the first three-way solenoid valve to its normally closed port 53, and finally enters the plunger pump 6 through its common port 51, completing the liquid aspiration. When the plunger pump 6 discharges liquid, the second three-way solenoid valve 5 is de-energized, its common port 51 is connected to its normally open port 52. Liquid flows out of the pipeline through the plunger pump 6, through the common port 51 to its normally open port 52, and finally exits through the pipeline from the sampling needle 7.

[0037] The liquid addition system of this application uses a first three-way solenoid valve 3 to control the switching between the main and backup liquid storage tanks, ensuring seamless switching to the backup tank when the liquid level in either tank is insufficient, preventing air from entering and maintaining continuous liquid addition. Through the dynamic switching of the state of the second three-way solenoid valve 5, physical isolation of the liquid aspiration and discharging paths is achieved, which not only avoids the risk of liquid backflow, but also ensures the independence and controllability of the sample addition action.

[0038] In one embodiment, a first liquid level sensor 8 is provided on the outside of the first liquid storage tank 1, and a second liquid level sensor 9 is provided on the outside of the second liquid storage tank 2. The first liquid level sensor 8 and the second liquid level sensor 9 can monitor the liquid level in the first liquid storage tank 1 and the second liquid storage tank 2 in real time, respectively. Their function is to provide intelligent liquid volume management for the liquid filling system by monitoring the liquid level in real time. Specifically, the liquid level sensor (e.g., capacitive or ultrasonic sensor) accurately acquires liquid level data through non-contact or contact measurement technology and transmits the signal to the host computer control system in real time. The host computer performs dynamic analysis based on preset alarm thresholds (e.g., minimum safe liquid level): when the liquid level in a certain storage tank approaches or falls below the alarm value, the system automatically triggers the switching logic of the first three-way solenoid valve 3, seamlessly activating the backup liquid storage tank for liquid supply, thereby avoiding the risk of air contamination due to insufficient liquid volume and ensuring the continuity and stability of the liquid filling process. Furthermore, the data from the liquid level sensors can also be used to optimize reagent consumption tracking and inventory management, predicting reagent remaining quantities through historical liquid level change trends, and assisting operators in planning replacement cycles in advance.

[0039] In one embodiment, suction needles 10 are provided at the connection points of the first liquid filling line 11 and the first liquid storage tank 1, and at the connection points of the second liquid filling line 12 and the second liquid storage tank 2. This design ensures that the liquid is accurately and efficiently drawn from the storage tank. The suction needles 10 allow the liquid to flow more smoothly from the storage tank into the filling line when drawn by the plunger pump 6, avoiding problems such as air bubbles or liquid splashing that may occur during the extraction process, thereby improving the stability and accuracy of liquid filling.

[0040] In one embodiment, the end of the suction needle 10 is equipped with an anti-fragmentation structure (such as a passivated needle tip, a flexible sealing ring, or a built-in screen). This anti-fragmentation structure effectively prevents minute impurities and debris generated during liquid tank replacement or liquid extraction from entering the dispensing system. For example, when inserting or removing the suction needle 10, friction may generate tiny metal or plastic fragments. If these fragments enter the system, they may clog pipelines or damage precision components, such as the three-way solenoid valve and the plunger pump 6. By providing an anti-fragmentation structure at the end of the suction needle 10, impurities can be intercepted, ensuring that the liquid entering the dispensing system is pure and free of impurities. This not only improves the stability and reliability of the system but also extends the service life of the equipment and reduces maintenance costs and downtime caused by impurities. Furthermore, the anti-fragmentation structure design further enhances the safety of the system, avoiding potential failure risks caused by impurities.

[0041] In one embodiment, a filter 4 is installed on the pipeline between the normally closed port 53 of the second three-way solenoid valve and the common port 31 of the first three-way solenoid valve. Its core function is to filter out metal debris, particulate impurities, or contaminants that may be present in the liquid path through a physical interception mechanism. Located at a critical node in the liquid path switching process, the filter 4 covers the entire liquid flow direction during the switching process between the two storage tanks. This ensures that whether the liquid is supplied from the main tank or the backup tank, all reagents flowing through it must pass through the filter layer, thereby preventing impurities from entering the interior of precision components such as the plunger pump 6 and solenoid valves, reducing the risk of mechanical failures caused by particulate matter jamming or wear. Furthermore, the integrated design of the filter 4 requires no additional operational intervention, effectively extending the service life of critical components through passive protection while maintaining the cleanliness of the liquid path, ensuring the accuracy of the sample dosage and the repeatability of the test results. Combined with the anti-debris structure at the end of the aspiration needle 10, this technical solution constructs a multi-level physical barrier, systematically solving the contradiction between impurity contamination and equipment reliability in traditional liquid dispensing systems.

[0042] In one embodiment, filter 4 is a microporous membrane structure, which has the advantage of efficiently intercepting tiny particulate matter (such as metal debris, fibrous impurities, or colloidal contaminants) in the liquid path through a physical sieving mechanism. The uniformly distributed pore size of the membrane ensures liquid flow while blocking impurities at the front end of the liquid path, preventing them from entering core components such as the plunger pump 6 and solenoid valves, thus avoiding blockage or mechanical wear. The chemical inertness and corrosion resistance of the microporous membrane enable it to be compatible with various biochemical reagents, allowing for long-term stable operation without degradation or pore size deformation, ensuring the durability of filtration performance.

[0043] In one embodiment, the filter 4 is a filter screen, whose structure can employ multiple layers of mesh with different pore sizes. The outer layer intercepts larger particulate impurities, while the inner layer filters smaller particles, thus achieving graded filtration. This ensures filtration effectiveness while avoiding excessively slow filtration speed. The material of the filter screen can be selected according to the properties of the liquid; for example, stainless steel is suitable for general chemical reagents, while polytetrafluoroethylene (PTFE) is suitable for highly corrosive liquids. In one embodiment, the end of the sampling needle 7 is equipped with an anti-drip structure. Through surface tension control or mechanical seal design (such as hydrophobic coating, microporous flow restriction, etc.), the problem of residual droplets or uncontrolled dripping at the needle tip after liquid addition is effectively solved. In actual operation, after the sampling needle 7 has discharged the liquid, dripping may occur due to surface tension or residual liquid. This not only leads to liquid waste but may also contaminate the experimental environment and affect the accuracy of subsequent detection. By setting an anti-drip structure at the end of the sampling needle 7, it can be ensured that the liquid can completely detach from the sampling needle 7 after discharge, avoiding dripping.

[0044] In one embodiment, the tubing of the liquid addition system is made of corrosion-resistant materials. This design fully considers the complexity of the various chemical reagents that the electrochemiluminescence instrument may encounter in practical applications. The use of corrosion-resistant materials ensures that the tubing maintains stable performance even after long-term contact with liquids of different properties, such as acids, alkalis, or organic solvents, effectively preventing problems such as tubing damage and liquid leakage caused by material corrosion. Furthermore, the use of corrosion-resistant tubing further guarantees the accuracy of the detection results, avoiding potential interference factors introduced by chemical reactions between the tubing material and the reagents.

[0045] In one embodiment, the liquid filling system also includes a host computer. Both the first liquid level sensor 8 and the second liquid level sensor 9 are set with alarm liquid levels. The host computer receives signals from either the first liquid level sensor 8 or the second liquid level sensor 9 to control the on / off state of the first three-way solenoid valve. This design achieves automated and intelligent control of the liquid filling system, improving its operating efficiency and stability. By monitoring the liquid level in the storage tank in real time through the liquid level sensors, and automatically triggering the host computer to control the three-way solenoid valve to switch the supply tank when the liquid level drops to the set alarm level, not only is liquid filling interruption due to insufficient liquid level avoided, but air contamination into the system is also effectively prevented, ensuring the continuity and stability of the liquid filling process. Furthermore, the introduction of the host computer facilitates monitoring and management of the entire liquid filling process. Operators can intuitively understand the system's operating status through the host computer interface, promptly detect and handle abnormal situations, further improving the system's reliability.

[0046] In one embodiment, after switching to the standby storage tank for liquid supply, the original main storage tank can immediately enter the reagent replenishment or replacement process. Operators can inject new reagent into the empty tank via an independent filling port or quick interface without interrupting system operation. The host computer can monitor the liquid level recovery status of the replenishment tank via a level sensor. When the liquid level reaches a preset safety threshold, the system automatically reinstates it to the switching queue, ensuring that the two tanks are always in a "one in use, one in standby" cycle. This dynamic replenishment mechanism not only eliminates the downtime caused by liquid replacement in traditional single-tank systems but also achieves an efficient "run-while-maintain" operation mode through redundant design, making it particularly suitable for long-term continuous testing tasks. Simultaneously, the anti-fragmentation structure of the aspiration needle 10 and the continuous interception function of the filter 4 effectively prevent external contaminants from entering the system during replenishment, ensuring the cleanliness of the replenished reagent and the stability of the liquid path.

[0047] In one embodiment, the host computer includes an alarm structure that issues an alarm signal when the liquid level in the first storage tank 1 or the second storage tank 2 falls below the alarm level. This alarm mechanism provides additional safety for the liquid filling system, ensuring that operators can respond promptly to insufficient liquid levels. By monitoring the liquid level in real time and issuing alarms, the system effectively avoids liquid filling interruptions or equipment idling due to liquid depletion, thereby protecting critical components from damage and extending equipment lifespan. Simultaneously, the timely alarm signal improves operational convenience and efficiency, enabling operators to quickly take measures, such as replacing the storage tank or replenishing the liquid, without affecting the testing process.

[0048] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A liquid addition system for an electrochemiluminescence instrument, characterized in that, The liquid dispensing system includes: The first and second liquid storage tanks are used to hold liquids. The first three-way solenoid valve has a normally open port connected to the first liquid storage tank via a first liquid supply line, and a normally closed port connected to the second liquid storage tank via a second liquid supply line. The first three-way solenoid valve is used to switch the connection between the first liquid supply line, the second liquid supply line, and the common port of the first three-way solenoid valve. The second three-way solenoid valve has its normally open port connected to the sampling needle via a pipeline, and its normally closed port connected to the common port of the first three-way solenoid valve via a pipeline. The common port of the second three-way solenoid valve is connected to the plunger pump via a pipeline. The second three-way solenoid valve is used to control the flow direction of the liquid.

2. The liquid addition system according to claim 1, characterized in that, The first liquid storage tank is equipped with a first liquid level sensor on its outer side, and the second liquid storage tank is equipped with a second liquid level sensor on its outer side.

3. The liquid addition system according to claim 1, characterized in that, A suction needle is provided at the connection between the first liquid addition pipeline and the first liquid storage tank, and at the connection between the second liquid addition pipeline and the second liquid storage tank.

4. The liquid addition system according to claim 3, characterized in that, The end of the suction needle is equipped with a debris-proof structure.

5. The liquid addition system according to claim 1, characterized in that, A filter is installed on the pipeline between the normally closed port of the second three-way solenoid valve and the common port of the first three-way solenoid valve.

6. The liquid addition system according to claim 5, characterized in that, The filter is a filter screen.

7. The liquid addition system according to claim 1, characterized in that, The tip of the sample dispensing needle is equipped with an anti-drip structure.

8. The liquid addition system according to claim 1, characterized in that, The piping of the liquid addition system is made of corrosion-resistant materials.

9. The liquid addition system according to claim 2, characterized in that, The liquid addition system also includes a host computer. Both the first liquid level sensor and the second liquid level sensor are set with alarm liquid levels. The host computer is used to receive signals from the first liquid level sensor or the second liquid level sensor to control the on / off state of the first three-way solenoid valve.

10. The liquid addition system according to claim 9, characterized in that, The host computer includes an alarm structure that can issue an alarm signal when the liquid level in the first or second liquid storage tank is lower than the alarm level.

Images