CN-117138859-B - Pipetting control method and application of pneumatic pipetting pump

CN117138859BCN 117138859 BCN117138859 BCN 117138859BCN-117138859-B

Abstract

The invention relates to a pipetting control method of a pneumatic pipetting pump, and belongs to the technical field of automatic pipetting equipment. The liquid level detection method comprises the steps of S1, starting an air pressure real-time acquisition system to acquire an air pressure value in a liquid level piston cylinder, S2, controlling the liquid level to move towards the liquid level, simultaneously controlling a piston in the liquid level to move towards the liquid level according to a preset speed, enabling the piston cylinder to generate an air flow which is continuously blown outwards, and S3, judging to contact and detect the liquid level when an air pressure sensor in the liquid level acquires that a variation difference value of an air pressure waveform amplitude variation is larger than a preset liquid level trigger threshold value. The control method is based on the air pressure feedback control pipetting process, can flexibly identify the liquid level and accurately acquire the position information of the liquid object, and compared with the conventional air pressure type detection, the control method has the advantages of high air pressure detection response speed, high air pressure detection sensitivity and high flexible adjustment.

Inventors

WANG XIAORUI
CHANG XIONG
Zhi Meizhao
XU TENG
LI YONGJUN

Assignees

广州微远基因科技有限公司
广州微远医疗器械有限公司
广州微远医学检验实验室有限公司
深圳微远医疗科技有限公司
北京微远医学检验实验室有限公司
广州微远智造科技有限公司
广州微远医学科技有限公司

Dates

Publication Date: 20260505
Application Date: 20230830

Claims (8)

1. A pipetting control method of a pneumatic pipetting pump, comprising a liquid level detection step comprising: S1, starting an air pressure real-time acquisition system to acquire an air pressure value in a piston cylinder of a liquid transfer pump; s2, controlling a piston in the liquid transfer pump to move upwards by a preset distance, controlling the liquid transfer pump to move towards the liquid level, and simultaneously controlling the piston in the liquid transfer pump to move towards the liquid level at a preset speed, so that a piston cylinder generates an air flow which is continuously blown outwards; and S3, when the air pressure sensor in the liquid transferring pump collects that the variation difference value of the air pressure waveform amplitude variation is larger than the preset liquid level triggering threshold value, judging that the air pressure sensor contacts and detects the liquid level, wherein the air pressure waveform amplitude is subjected to filtering processing, namely, after the air pressure values are collected at preset time points, sorting the air pressure values according to the air pressure values, removing a plurality of air pressure values which are ranked forward and backward, and carrying out average processing on the rest air pressure values to be used as the variation difference value for judging the air pressure waveform amplitude variation.
2. The method according to claim 1, wherein in the step S2, the distance between the origin and the contact position of the liquid surface detected by the liquid transfer pump is the descending height, the depth of the liquid to be transferred is calculated by the distance between the bottom of the container containing the liquid to be transferred and the origin, and the volume of the liquid to be transferred is calculated by combining the shape of the container.
3. The method according to claim 1, wherein in the step S3, the air pressure waveform amplitude is subjected to a filtering process of collecting air pressure values at time points spaced by 100+ -20 μs, sorting the air pressure values at 30+ -10 time points according to the air pressure values, removing air pressure values 5+ -3 before and after sorting, and performing an averaging process on the remaining air pressure values as a variation difference for determining a variation of the air pressure waveform amplitude.
4. The pipetting control method of a pneumatic pipetting pump according to claim 1, further comprising a pipetting step of: and S4, controlling a piston in the liquid transfer pump to carry out liquid suction, and simultaneously controlling the liquid transfer pump to move downwards along with the descending of the liquid level so as to enable the gun head to keep the depth of immersing the gun head into the liquid level within a preset range.
5. The method according to claim 4, further comprising a pipetting step of pipetting a liquid, the pipetting step being accompanied by the pipetting step, the pipetting step comprising suction monitoring, bubble monitoring and clogging monitoring; comparing an air pressure value waveform acquired in real time with a preset normal pipetting waveform, and judging as suction when the variation difference value of the amplitude variation of the air pressure waveform is smaller than the variation difference value of the amplitude variation of the preset suction waveform in the pipetting process; Comparing an air pressure value waveform acquired in real time with a preset normal pipetting waveform, and judging that the air pressure value waveform is blocked when the variation amplitude of the air pressure value waveform is larger than the variation amplitude difference value of the preset normal waveform and is in a low-pressure state continuously in the pipetting process; Comparing an air pressure value waveform acquired in real time with a preset normal pipetting waveform, and judging as a suction air bubble when the air pressure value waveform variation amplitude is between a preset normal waveform variation amplitude difference value and a preset suction air waveform variation amplitude difference value in the pipetting process; The normal waveform variation amplitude difference is larger than the suction waveform variation amplitude difference.
6. The method according to any one of claims 1 to 5, further comprising a drop prevention step after completion of the pipetting step, the drop prevention step comprising: And S5, monitoring the collected air pressure value in real time to obtain an air pressure value as an anti-falling initial value when the air pressure value waveform amplitude changes beyond a threshold value, and controlling the piston to move upwards to return to the liquid suction body so as to restore the air pressure value to the initial value range.
7. The method for controlling a pneumatic liquid transfer pump according to claim 6, the method is characterized by further comprising a liquid separation step, wherein the liquid separation step comprises the following steps: And S6, controlling a piston in the liquid transfer pump to separate liquid, and simultaneously controlling the liquid transfer pump to move upwards along with the rising of the liquid level so as to keep the distance between the gun head and the liquid level within a preset range.
8. A pneumatic liquid transferring pump, which is characterized by comprising a liquid transferring pump assembly and a liquid transferring control system, wherein the liquid transferring control system adopts the control method of any one of claims 1-7 to complete liquid transferring operation.

Description

Pipetting control method and application of pneumatic pipetting pump Technical Field The invention relates to the technical field of automatic pipetting equipment, in particular to a pipetting control method and application of a pneumatic pipetting pump. Background With the rapid development of science and technology, laboratory such as biology, chemistry, environment, medicine research and development, food and the like and unit pipetting work such as hospitals, disease control, blood stations and the like enter into standardization, an automatic pipetting system (or pipetting workstation) in the market becomes gradually popular in the face of more complex study objects and increasing sample numbers, and pipetting transfer positions and pipetting process quality in the pipetting workstation determine pipetting accuracy and experimental timeliness, wherein a pneumatic liquid level detection and pipetting process quality monitoring system is the most important link of pipetting working equipment and is a set of most efficient and complex methodology system requiring stable accuracy. However, due to the limitation of the technology, the traditional liquid level fixing liquid transfer mode needs to completely go deep to a fixed or unknown position below the liquid level to perform liquid transfer operation, so that the defects of liquid quality loss and inaccurate actual liquid transfer amount exist, and the accuracy of experiments is affected. Based on this, various techniques have been adopted to detect the liquid level during pipetting, such as the air pressure type liquid level detection method and apparatus disclosed in CN112473760a, which detect the liquid level position by utilizing the change of air pressure in contact with the liquid level. Meanwhile, there is a pneumatic pipette disclosed in CN215087261U, which can accurately judge whether the suction head is contacted with the liquid level by detecting the air pressure value in the air cylinder and the external air pressure value and comparing the air pressure difference between the air pressure value and the external air pressure value, so that the problems that the repeated air discharge and air suction adopted in the prior art cause liquid aspiration pollution are avoided, the air in the air cylinder needs to be emptied after air suction, and the reagent is blown out of a test tube during air blowing and the like are solved. However, the above solutions have the problems that the pressure in the cavity can be changed only by contacting the liquid surface, even immersing the cavity below the liquid surface, and the pressure in the cavity is slow to change and react, which results in longer detection time. In order to rapidly and sensitively detect the liquid level, the liquid transfer pump also comprises a liquid transfer pump as disclosed in CN115069322A, wherein the liquid transfer pump is used for detecting by adopting a double detection system of an air pressure detection system and a capacitance detection system, and the conductive suction head is contacted with the solution to be sampled to generate a capacitance signal so as to judge that the conductive suction head reaches the liquid level of the solution to be sampled. However, such a transfer pump requires a conductive shampoo, so that the consumable cost is greatly increased, and the stability and precision of the capacitive detection system are affected by the fact that the capacitive characteristics are easily interfered by magnetic fields of surrounding environments, so that the technical popularization is adversely affected. Disclosure of Invention Based on the above, it is necessary to provide a pipetting control method of a pneumatic pipetting pump for solving the problems of low detection precision, certain delay or higher cost of the automatic pipetting device, wherein the control method is based on pneumatic feedback control pipetting process, can flexibly identify liquid level and accurately acquire the position information of a liquid object. A pipetting control method of a pneumatic pipetting pump, comprising a liquid level detection step comprising: S1, starting an air pressure real-time acquisition system to acquire an air pressure value in a piston cylinder of a liquid transfer pump; s2, controlling the liquid transfer pump to move towards the liquid level, and simultaneously controlling a piston in the liquid transfer pump to move towards the liquid level according to a preset speed, so that a piston cylinder generates an air flow which is continuously blown outwards; And S3, judging that the liquid level is contacted and detected when the air pressure sensor in the liquid transfer pump collects that the variation difference value of the amplitude variation of the air pressure waveform is larger than a preset liquid level trigger threshold value. The inventor finds in earlier research that in the conventional technology, the air pressure in the cavity of the piston cylin