CN120085023A

CN120085023A - A liquid path system for sampling quality detection and abnormal detection process

Info

Publication number: CN120085023A
Application number: CN202510578347.2A
Authority: CN
Inventors: 张桢阳; 李向坤; 高凯悦; 赵孝连; 沈国金; 黄鹤
Original assignee: Jiaxing Kaishi Biotechnology Co ltd
Current assignee: Jiaxing Kaishi Biotechnology Co ltd
Priority date: 2025-05-07
Filing date: 2025-05-07
Publication date: 2025-06-03
Anticipated expiration: 2045-05-07
Also published as: CN120085023B

Abstract

The present invention belongs to the technical field of biological liquid sample detection, and specifically relates to a liquid circuit system for sample suction quality detection and an abnormality detection process. A liquid circuit system for sample suction quality detection includes a capacitance detection module, a syringe, a pressure detection module, a cleaning valve, a cleaning pump, a degassing module and a water tank connected in sequence, and the capacitance detection module, the syringe, the pressure detection module, the cleaning valve, the cleaning pump, the degassing module and the water tank are connected by pipelines. It mainly solves the following problems: 1. The contradiction between the pressure monitoring range and the monitoring resolution; 2. When the sample is insufficient or bubbles are inhaled, the difference between the suction pressure and the normal liquid suction pressure is small, which can easily cause misjudgment; 3. It is easily disturbed by noise signals, causing misjudgment; 4. Other processes such as cleaning and adding samples lack corresponding error monitoring mechanisms; 5. Over-reliance on a single method for monitoring, and the pressure of the test process is easily disturbed.

Description

Liquid path system for detecting sample suction quality and anomaly detection flow

Technical Field

The invention belongs to the technical field of biological liquid sample detection, and particularly relates to a liquid path system for detecting sample suction quality and an abnormality detection flow.

Background

An in vitro diagnostic device (In Vitro Diagnostic Devices, abbreviated as IVD) refers to a medical device that detects and analyzes collected human samples (e.g., blood, urine, interstitial fluid, etc.) outside the human body to obtain clinical diagnostic information, monitor disease states, or evaluate physiological functions. These devices are widely used in a variety of medical settings and are critical to disease prevention, diagnosis, therapy monitoring, and health management. The in vitro diagnostic instruments are various, and can be classified into biochemical analyzers, immune analyzers, blood analyzers, molecular diagnostic instruments, microorganism detectors, blood coagulation analyzers, urine analyzers, POCT (point of care testing) devices and the like according to different detection principles, target analytes and application scenes.

At present, the development trend of the in-vitro diagnostic instrument is high speed, high precision and high automation, and the precision and the speed of the sample adding process are one of the main factors influencing the performance of the instrument. As the amount of sample required for single detection becomes smaller, the requirement for the precision of sample addition becomes higher. Any disturbance or deviation in the sample application process may cause errors in the detection results, and therefore it is important to perform effective state monitoring on the sample application process to ensure accurate sample or reagent transfer and addition during the test.

In practical application, due to the complexity of the sample to be transferred, deviation of sample suction and sample addition is easy to occur. Typical problems are clogging of the aspiration needle, insufficient sample, air bubble interference, etc.

Currently, the means for monitoring the quality of the sample transfer is mainly monitoring the pressure changes during the sample aspiration process. The pressure monitoring range and the monitoring resolution are contradictory, namely, because the sample sucking needle is generally subjected to pressurized flushing when being cleaned, the cleaning pressure is larger (generally hundreds of kilopascals), the monitoring and pressure-resistant range of the pressure sensor is required to be larger, the pressure change is smaller (a plurality of kilopascals) along with the smaller and smaller sample amount in the sample sucking process, the pressure sensor is required to have high monitoring precision and resolution for a low-pressure part, 2. The pressure monitoring is mainly used for the needle blocking monitoring, the accuracy and the reliability are higher at present, because the difference between the suction pressure and the normal liquid suction pressure is larger when the needle blocking is carried out, misjudgment is not easy to be caused, and the difference between the suction pressure and the normal liquid suction pressure is smaller when the sample is insufficient or bubbles are sucked, 3. The sample sucking amount is smaller, the pressure difference signal is smaller when the suction speed is lower or the suction event is shorter, the noise signal interference is easy to be caused to be misjudgment, 4. The sample sucking process is only monitored, and the monitoring and the pressure difference signal is easy to be interfered by the noise signal when the sample sucking speed is lower or the suction event is shorter, and the pressure difference signal is easy to be monitored, and the monitoring mechanism is easy to be interfered by the monitoring system to be in a single mode, and the excessive, and the system is easy to be subjected to the excessive monitoring and the monitoring and has the excessive monitoring process is easy to be subjected to the excessive monitoring.

In order to overcome the defect of detecting pressure change during sample suction in the prior art, the invention hopes to provide a liquid path system and a software system for detecting the quality of the sample suction.

Disclosure of Invention

The invention aims to provide a liquid path system for detecting the quality of a sample and an abnormality detection flow, so as to solve the problems in the background technology.

In order to achieve the above purpose, the present invention provides the following technical solutions:

the liquid path system for detecting the sample suction quality comprises a capacitance detection module, an injector, a pressure detection module, a cleaning valve, a cleaning pump, a degassing module and a water tank which are sequentially connected, wherein the capacitance detection module, the injector, the pressure detection module, the cleaning valve, the cleaning pump, the degassing module and the water tank are connected through pipelines;

The capacitance detection module comprises a sample suction needle, wherein the sample suction needle is used for collecting capacitance signals, and further, the collected capacitance signals are input to an oscillator after being subjected to signal filtering;

the pressure detection module comprises a pressure sensor, wherein the pressure sensor is used for collecting and converting signals into electric signals, the collected signals are subjected to primary amplification and data filtering, and then high-pressure channel secondary amplification and low-pressure channel secondary amplification are further carried out simultaneously, a first analog-to-digital conversion module and a second analog-to-digital conversion module of the second control unit are used for collecting and converting the electric signals of the high-pressure channel secondary amplification and the electric signals of the low-pressure channel secondary amplification respectively, the analog electric signals are converted into digital signals, the digital signals are identified, whether pressure abnormality occurs is judged, and further the pressure data are reported through the second communication unit and stored in the storage unit.

Preferably, the sample sucking needle adopts a double-layer metal structure with nested inner walls and outer walls, the outer wall of the sample sucking needle is fixed on the sample arm moving assembly, an insulating layer is arranged between the inner wall and the outer wall of the sample sucking needle, a capacitance detection module is arranged on the sample arm moving assembly, and the inner wall and the outer wall of the sample sucking needle are simultaneously connected with a signal input end of the capacitance detection module.

Preferably, the pressure sensor is mounted in a vertical manner.

Preferably, the pressure sensor is arranged between the cleaning valve and the injector, and a pipeline between the pressure sensor and the injector is less than or equal to 200mm.

Preferably, the pipeline is a hard pipe, the movable part of the pipeline is U-shaped, and the U-shaped angles of the movable parts of the pipelines are consistent.

An abnormality detection flow of a liquid path system for detecting the quality of a sample, comprising the following steps:

Step 5, the sample suction needle is used for downwards probing into the liquid level, the pressure is delayed to be stable, and the initial pressure P0 is measured;

step 6, the injector starts to suck samples, a real-time pressure position Pr of the sucked samples is measured, when P0-Pr is equal to or less than a needle blocking threshold value, the suction of the samples is ended, the needle blocking is reported, when P0-Pr is equal to or less than the needle blocking threshold value, the injector is enabled to wait for the real-time pressure stabilization in a constant speed section in a delayed manner, and the slope Kp of pressure data of the constant speed section at the moment is calculated;

step 7, ending the sample suction and reporting the suction bubbles when the fluctuation of the Kp data exceeds the limit, and judging whether the injector starts to decelerate or not when the fluctuation of the Kp data does not exceed the limit;

Step 8, judging whether the sample is sucked completely or not when the syringe does not start decelerating, returning to the step 6 if the sample is not sucked completely, and restarting the step 6;

Step 9, when the injector starts decelerating, measuring the real-time pressure Pp before decelerating, when P0-Pp is smaller than the suction threshold value, ending suction, reporting suction, when P0-Pp is larger than or equal to the suction threshold value, judging whether suction is finished, if not, returning to step 6, and restarting step 6;

and 10, when the sample suction is judged to be finished in the steps 8 and 9, stopping the injector, measuring the end pressure Pend, reporting partial blockage if the P0-Pend is more than a partial blockage threshold, and when the P0-Pend is less than or equal to the partial blockage threshold, causing no abnormality in the liquid path.

Preferably, after the sample is detected by the sample sucking needle, the sample of the sample sucking needle is replaced, and the sample sucking needle is cleaned before the new sample is replaced:

step 1, judging whether the cleaning is finished, if the cleaning is not finished, returning to the cleaning, and judging whether the cleaning is finished, if the cleaning is finished, delaying to wait for the real-time pressure to be stable;

and step 2, if the real-time pressure P is greater than or equal to the cleaning blocking threshold, normally ending, and if the real-time pressure P is less than or equal to the cleaning blocking threshold, reporting that the needle is blocked.

Preferably, after the sample sucking needle is cleaned and before the sample sucking, judging the needle blocking condition of the sample sucking needle, wherein the step of judging the needle blocking is as follows:

step 3, judging whether the isolation air suction is finished or not, if the isolation air suction is not finished, returning to the process of ending the isolation air suction again, and if the isolation air suction is finished, judging whether the pressure P < normal recovery pressure is met or not;

And 4, if the pressure P is less than the normal recovery pressure, normally ending, and if the pressure P is more than or equal to the normal recovery pressure, reporting that the needle is blocked before the sample suction.

Preferably, the detecting step of the abnormal capacitance condition in the sample sucking process comprises the following steps:

(1) The sample sucking needle descends to the liquid level, and if the liquid level is detected, sample sucking is started;

(2) Detecting whether the sample sucking needle is separated from the liquid level after the liquid sucking starts, if so, reporting that the sample sucking is insufficient, ending the sample sucking, and if not, judging whether the sample sucking is ended;

(3) If the sample suction is finished, the sample suction needle is lifted, and whether the sample suction needle is separated from the liquid level is further detected;

(4) If the sample sucking needle is separated from the liquid level, the normal end is reached, and if the sample sucking needle is separated from the liquid level, the liquid level separation abnormality is reported.

Compared with the prior art, the invention has the beneficial effects that:

(1) The liquid path system for detecting the sample suction quality has the advantages that the pressure sensor is vertically arranged and is convenient for discharging bubbles, a hard pipe is used for the pipeline to reduce fluctuation of the pipeline and fix the pipeline to reduce shaking of the pipeline in the running process of a sample arm as much as possible, a U-shaped mode is adopted for the pipeline at an upper and lower movable part, and the consistent U-shaped angle in the running process is ensured;

(2) The invention provides a liquid path system for detecting the quality of a sample, which is characterized in that a sample sucking needle adopts a double-layer metal structure with nested inner walls and outer walls, the outer walls of the sample sucking needle are fixed on a sample arm moving assembly, an insulating layer is arranged between the inner walls and the outer walls of the sample sucking needle, a capacitance detecting module is arranged on the sample arm moving assembly, the inner walls and the outer walls of the sample sucking needle are simultaneously connected with a signal input end of the capacitance detecting module, the capacitance detecting module can judge the current environment (in air or in liquid) of the sample sucking needle through detecting the capacitance between the inner walls and the outer walls of the needle, so that the liquid level contact detection of the sample sucking needle can be realized;

(3) According to the liquid path system for detecting the sample suction quality, the pressure detection module is designed in a double-channel mode, so that the same pressure sensor can monitor a high pressure channel and a low pressure channel simultaneously, wherein the high pressure channel ensures a high pressure monitoring range in the processes of cleaning, needle blocking and the like, and meanwhile, the low pressure channel also ensures the detection resolution of a small amount of sample suction and the like for a small pressure difference;

(4) The liquid path system for detecting the sample sucking quality has the advantages that the capacitance value of the body of the sample sucking needle changes in the moving process, the sample sucking needle is input to the oscillator after being subjected to signal acquisition and filtering, the frequency of an output signal of the oscillator changes along with the change of the capacitance signal, the output frequency signal is input to the control unit counter to measure the frequency signal after being divided by the frequency divider, and when the sample sucking needle enters or leaves a liquid level, the capacitance value of the needle changes, the frequency of the output signal changes due to the changed capacitance value, and therefore a signal with completely different frequencies is generated and input to the control unit. The method and the device can be used for identifying whether the sample suction needle enters the liquid level or leaves the liquid level through real-time processing of signals by an algorithm in the control unit, and reporting the signals by the communication unit.

Drawings

FIG. 1 is a schematic diagram of a fluid circuit system connection according to the present invention;

FIG. 2 is a connection diagram of a capacitance detection module of a sample sucking needle;

FIG. 3 is a schematic diagram of a pressure detection module according to the present invention;

FIG. 4 is a schematic diagram of a capacitive sensing module according to the present invention;

FIG. 5 is a graph showing the real-time pressure change of the liquid path in the normal sample suction process;

FIG. 6 is a real-time pressure signal before and after 20-order 12Hz digital FIR low pass filtering;

FIG. 7 is a graph showing the pressure change curve of the complete blockage of the sample suction needle during the sample suction;

FIG. 8 is a graph showing the partial blockage pressure change curve of the sample sucking needle during sample sucking;

FIG. 9 is a graph showing the pressure change of the sample when the sample sucking needle is not sucking at all;

FIG. 10 is a graph of partial suction pressure curves (actual suction/target suction) at different scales;

FIG. 11 is an inhalation bubble pressure curve;

FIG. 12 is a flow chart of detecting pressure anomalies in the complete suction needle suction process;

FIG. 13 is a graph of pressure change during a cleaning process;

FIG. 14 is a cleaning needle blocking detection flow;

FIG. 15 shows a flow of needle blocking detection before sample aspiration;

FIG. 16 shows the capacitance change during normal sample sucking;

FIG. 17 is a graph showing the capacitance change during abnormal sample sucking;

fig. 18 is a flow chart of detecting capacitance abnormality in the sample sucking process.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The structure of the liquid path related to the sample sucking needle of the analyzer is shown in figure 1.

The cleaning pump is responsible for providing the cleaning pressure of the inner wall of the needle, the corresponding cleaning valve of the needle which needs to be cleaned is opened during cleaning, cleaning water flows out of the inner wall of the needle, and the cleaning valve is kept in a closed state during sample suction and discharge, and the sample suction and discharge are completed by the injector. The pressure detection module is arranged between the cleaning valve and the sample suction needle, and can detect the cleaning pressure and the sample suction and discharge pressure.

The pressure change of the whole sample suction needle liquid path is larger during cleaning, so that no special requirement is required for the mounting position of the sensor, and the pressure change of the sample suction needle liquid path is smaller during sample suction, so that the sensor is required to be mounted at a pressure sensitive part. Since the syringe is the source of pressure variation when the aspiration needle aspirates a sample, the sensor should be placed near the syringe.

The bubble has certain elasticity, and the existence of the bubble influences the change rule of the liquid path pressure, and generally causes the false detection of air suction. The presence of air bubbles in the liquid path elements such as needles, lines, pressure sensors, syringes, etc. must be avoided, and thus a degassing module is necessary.

In addition, the vibration of the pump, the pipeline and the sensor can cause abnormal pressure fluctuation, so that the false detection of the suction is caused, and the vibration of the liquid path element is avoided.

Experiments also find that excessive pipeline bending, winding, switching and reducing can influence the distinguishing degree of suction and should be avoided.

The capacitance detection structure is shown in fig. 2.

The sample sucking needle adopts an inner nested double-layer metal structure, the outer wall of the needle is fixed on the sample arm moving assembly, the inner layer and the outer layer are in an insulating design before, therefore, a certain capacitance is arranged between the inner wall and the outer wall of the needle, the inner wall and the outer wall are simultaneously connected to the signal input end of the capacitance detection module which is also fixed on the moving assembly, the capacitance detection module can judge the current environment (in air or in liquid) of the sample sucking needle through the detection of the capacitance between the inner wall and the outer wall of the needle, and therefore, the liquid level contact detection of the sample sucking needle can be realized.

The control unit controls the sample arm to move through the driving unit, so that the sample sucking needle can move to detect the liquid level, when the needle contacts the liquid level, the capacitance detection module detects the capacitance change and sends the capacitance change to the control unit, and the control unit controls the driving unit to stop moving, so that accurate liquid level detection can be realized.

Meanwhile, the sample suction needle should be always positioned in the liquid to be sucked in the sample suction process, the capacitance value of the sample suction needle should be kept stable, and the detection of the suction can be realized by detecting the capacitance value in the sample suction process when the air is sucked if the liquid quantity is insufficient.

The pressure detection circuit is designed as shown in fig. 3.

The signal output by the pressure sensor is collected by a signal collection module and converted into an electric signal (usually a voltage signal), the output electric signal is amplified once by an amplifier, and then data filtering is carried out by an analog low-pass filter to remove interference signals. The filtered signal is divided into two paths for secondary amplification, wherein the amplification factor of a low-voltage channel is higher, the detectable pressure signal range is smaller, but the signal resolution is higher at low voltage, and the amplification factor of a high-voltage channel is lower, the detectable pressure signal detection resolution is lower, but the detectable pressure signal range is larger.

The control unit collects the two channel signals at the same time and converts the analog signals into digital signals which can be identified by the controller through the analog-to-digital conversion module. And processing the signals through an algorithm in the control unit, namely identifying whether pressure abnormality occurs or not, reporting the pressure abnormality through the communication unit, and finally storing the pressure data into the storage unit so as to acquire the test data later.

The capacitive sensing circuit design is shown in fig. 4.

The sampling needle has a change of a body capacitance value in the motion process, the change of the body capacitance value is input to the oscillator after the signal acquisition circuit and the filtering, the frequency of an output signal of the oscillator can be changed along with the change of the capacitance signal, and the output frequency signal is input to the control unit counter for measuring the frequency signal after being divided by the frequency divider.

When the suction needle enters or leaves the liquid level, the capacitance value of the suction needle changes, and the changed capacitance value can change the frequency of the output signal, so that a signal with completely different frequency is generated and input into the control unit. The signal is processed in real time through an algorithm in the control unit, so that whether the sample suction needle enters the liquid level or leaves the liquid level can be identified, and the signal is reported through the communication unit.

The basic basis of the detection of the quality of the sucked sample is the real-time pressure of the liquid path of the sucking needle.

The pressure change rule of the liquid path in the typical sample sucking process is shown in fig. 5.

The process comprises the steps of enabling a sample sucking needle to contact a liquid level, starting sample sucking, enabling pressure to be reduced, enabling the pressure to be reduced to a certain level when the speed of the syringe reaches the maximum, enabling the syringe to keep constant-speed sample sucking, enabling the pressure to reach balance (the pressure of a sample with high viscosity is continuously reduced), enabling the syringe to start decelerating, enabling the pressure to start to recover, and enabling the pressure to end and recovering to static pressure.

Firstly, defining the following terms, namely an initial pressure P0, namely the hydrostatic pressure of liquid in a pipeline under normal conditions, namely the real-time pressure in the sample sucking process, a process pressure Pp, namely the pressure before the syringe decelerates (at a uniform speed end section), and an end pressure Pend, namely the pressure after the sample sucking is finished.

Data processing

For more remarkable abnormal sample suction (blockage or rapid sample suction with large volume), the difference can be clearly found through pressure detection, but when the sample suction volume is reduced or the speed is reduced, the amplitude of the pressure change becomes small, and meanwhile, the abnormal pressure detection becomes difficult due to the existence of system noise. This noise is mainly due to vibrations generated inside the system, such as the operation of the pump, vibrations of the sample arm or the tubing, etc., and other mechanical parts outside the system. Therefore, in order to improve the reliability of pressure abnormality detection, it is necessary to remove these interference signals. The vibration signal frequency is measured mainly in the range of >20Hz, so that the interference noise can be filtered by means of low-pass filtering (including analog low-pass filtering or digital low-pass filtering).

Fig. 6 is a pressure signal before and after 20-order 12Hz digital FIR low pass filtering.

Pressure characteristics of needle blocking in sample sucking process

The law of the change of the liquid path pressure when the blockage (such as the clot) is encountered in the sample sucking process is shown in figure 7. Compared with normal sample suction, the pressure-variable device has the characteristics that (1) the pressure change amplitude is related to a blockage but is generally larger than that of normal sample suction, and (II) the pressure cannot be recovered after the sample suction is finished.

Therefore, whether the needle is blocked can be judged according to the pressure difference of the maximum pressure variation amplitude P0-Pr in the sample sucking process, and whether the needle is blocked or not can be judged according to the pressure condition after the sample is sucked, namely, whether the needle is blocked or not is judged according to the pressure difference of P0-Pr.

In addition, in practical applications, due to the complexity of the sample to be aspirated, it may result in the aspiration of impurities, but without causing complete obstruction of the aspiration needle. For example, the viscosity of the sample to be sucked is too high, or a small clot adheres to the inner wall of the sample sucking needle, so that the sample sucking needle is not completely blocked, but the sample sucking state is still abnormal, and the sample sucking and sample adding precision is affected. In this case, the law of pressure change in the liquid path is shown in fig. 8, and after the sample suction is completed (the red dotted line in the figure), the pressure cannot be recovered normally. In addition, the partial blockage degree can be estimated according to the pressure condition at the moment.

Pressure characteristics of suction during sample suction

The law of the change of the liquid path pressure when the sample is not sucked at all (such as the sample is not placed or the liquid level is detected erroneously) is shown in fig. 9. Is characterized in that the variation of the suction pressure is small.

Therefore, whether the suction is generated or not, namely, whether the air is completely sucked or not can be judged according to the pressure difference of the pressure change range P0-Pp in the suction process.

The law of the change of the liquid path pressure when suction occurs in the later stage of sample suction (such as too little sample amount or insufficient insertion depth) is shown in figure 10. The pressure rising at the later stage of the constant speed stage of the injector can be judged by the variation of the pressure at the stage and the initial pressure, namely whether partial suction occurs or not can be judged according to the pressure difference of the pressure variation range P0-Pp in the sample suction process, and can be judged according to whether the pressure in the constant speed stable section fluctuates or not, namely, the slope variation of the pressure in the constant speed stable section exceeds a threshold value, and meanwhile, the time when air is sucked and the duty ratio of the sucked air can be judged according to the time point of the slope variation.

In addition to the insufficient amount of sample to be sucked, there is a possibility that the air bubbles exist in the solution to be sucked itself, and the insufficient amount of sample to be sucked is also caused when the air bubbles are sucked. At this time, the pressure is shown mainly as shown in fig. 11, and irregular fluctuation occurs in the pressure during the uniform sample suction process of the syringe.

And the pressure abnormality detection flow chart 12 of the complete sample sucking process of the sample sucking needle is shown by combining the abnormal characteristics.

And (3) cleaning and pressure detection before sample suction, namely, besides detecting abnormality of the sample suction process, pressure detection can be carried out in some preparation stages before sample suction, a sample analyzer usually cleans before sample suction so as to remove carrying pollution brought by the last sample suction process, and a small amount of air can be sucked before sample suction so as to isolate system liquid in a sample suction needle from a sample to be sucked. The cleaning and isolation air suction processes can be detected, and anomalies occurring in these processes can be identified to prevent anomalies from occurring prior to sample suction, and then related sample suction operations can still be performed.

Cleaning the blocking needle, namely a typical cleaning process liquid path pressure change rule chart 13. The device has the characteristics that after the cleaning valve is opened, the pressure of the liquid path is rapidly increased, and after the valve is closed, the pressure is rapidly recovered. The pressure change is evident.

The pressure of the liquid path when the needle is still blocked after cleaning is characterized in that after cleaning is finished, the pressure cannot be quickly recovered and is very slowly reduced. Therefore, the real-time pressure can be detected after the cleaning is finished, and whether the cleaning needle blockage occurs or not can be judged.

The blocking needle before the sample suction usually sucks a small amount of air before the sample suction, and if the needle is blocked at the moment, the characteristics of the blocking needle are similar to those of the blocking needle in the sample suction process. Therefore, the situation of pressure recovery after the end of sucking air can also be used for judging whether the needle is blocked before sucking the sample. The system judges the cleaning needle blocking after cleaning is finished, and the detection flow is shown in fig. 14. The system judges that the needle is blocked before the sample is sucked (after the air is isolated), and the detection flow is shown in figure 15.

In the aspect of detection of a needle blockage, the pressure change is obvious, so that the detection of the needle blockage has higher accuracy and reliability, and in the aspect of suction detection, if the suction quantity is small, the pressure change difference is small, and a certain detection error possibly exists, so that the detection of the suction abnormality can be performed by using two combined detection modes of pressure and capacitance at the same time for improving the reliability.

The capacitance detection in the sample sucking process is basically based on the change of the capacitance in the sample sucking process, and reflects the environment of the sample sucking needle in the sample sucking process.

The capacitance characteristic of the normal sample sucking process is that the capacitance change rule of the typical sample sucking process is shown in figure 16.

The process is divided into the following parts:

(1) The sample sucking needle descends to detect the liquid level, and the capacitance value slowly rises along with the sample sucking needle approaching the liquid to be sucked;

(2) The sample sucking needle contacts the liquid level, the capacitance value is rapidly increased, and the liquid level is detected;

(3) The sample sucking needle stops descending;

(4) The injection pump starts to suck samples, in the process of sucking samples, in order to ensure full-amount sample sucking, a sample sucking needle is always kept below the liquid level, and at the moment, the capacitance value is kept at a high level;

(5) Ending the sample suction;

(6) The sample sucking needle is lifted off the liquid level, and the capacitance value is rapidly reduced at the moment and is restored to the state in the air.

The capacitance characteristic of suction in the suction process is that when suction (insufficient sample, abnormal liquid level position and the like) is generated in the suction process, the change rule of the capacitance is shown as figure 17. Compared with normal sample suction, the method has the characteristics that when the sample suction process is not finished, the sample suction needle is separated from the liquid level, so that the capacitance value is reduced in advance. Therefore, whether or not a suction event has occurred can be determined based on the timing at which the off-liquid-level event (the capacitance value decreases), and if the off-liquid-level of the suction needle has been detected when the suction process has not ended, it can be determined that an abnormal suction has occurred.

And the abnormal detection flow of the sample sucking process is that the abnormal characteristics are combined, and the detection flow of the capacitance related to the abnormal sample sucking process of the sample sucking needle is shown in figure 18.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The liquid path system for detecting the sample sucking quality is characterized by comprising a capacitance detection module, an injector, a pressure detection module, a cleaning valve, a cleaning pump, a degassing module and a water tank which are connected in sequence, wherein the capacitance detection module, the injector, the pressure detection module, the cleaning valve, the cleaning pump, the degassing module and the water tank are connected through pipelines;

2. The liquid path system for detecting the quality of a sample according to claim 1, wherein the sample sucking needle is of a double-layer metal structure with nested inner walls and outer walls, the outer walls of the sample sucking needle are fixed on a sample arm moving assembly, an insulating layer is arranged between the inner walls and the outer walls of the sample sucking needle, a capacitance detection module is arranged on the sample arm moving assembly, and the inner walls and the outer walls of the sample sucking needle are simultaneously connected to a signal input end of the capacitance detection module.

3. The fluid path system for detecting the quality of a sample according to claim 1, wherein said pressure sensor is installed in a vertical manner.

4. The liquid path system for detecting the quality of a sample according to claim 1, wherein the pressure sensor is arranged between the cleaning valve and the injector, and a pipeline between the pressure sensor and the injector is less than or equal to 200mm.

5. The liquid path system for detecting the quality of a sample as set forth in claim 1, wherein the pipe is a hard pipe, the movable parts of the pipe are U-shaped, and the U-shaped angles of the movable parts of the pipe are identical.

6. An abnormality detection flow of the liquid path system for sample suction quality detection according to claim 1, comprising the steps of:

7. The abnormality detection flow of a liquid path system for quality detection of a sample according to claim 6, wherein after the sample is detected by the sample suction needle, the sample of the sample suction needle is replaced, and the sample suction needle is cleaned before the replacement of the new sample, and the cleaning blocking condition is judged during the cleaning of the sample suction needle, and the cleaning blocking judgment comprises the steps of:

8. The abnormality detection flow of a liquid path system for detecting a quality of a sample according to claim 6 or 7, wherein the step of judging a needle blocking condition of a sample suction needle after cleaning the sample suction needle and before suction of the sample, comprises the steps of: