The Research And Development Of Precision Sampling System Applied In Biochemical Analyzer

With the development of medical technology and engineering technology, users’ demands for automatic biochemical analyzer with high repeatability of sampling and precision of pumping lofting has become more and more urgent.In this paper an automatic sampling device for high precision trace liquid is designed and produced under the circumstance. The aim of this device is to drawing and releaseing both sample and reagent under precised quantification.By investigation and analyzation, the scheme of automatic micro liquid sampling devive was designed according to the requirement of automatic biochemical analyzer in domestic. Designing scheme includes the following parts:1. Lots of research was done on the mechanical transmission mechanism of the device at home. By analyze the merits and demerits of several transmission mechanisms; design of mechanical transmission mechanism suitable for this research is determined. In the mean time, some tests are done to check the performance of it.2. Designation of syringe module.Tihe module includes syringe syringe piston rod, syringe body, and sealing structure. According to the design requirements, three sets of piston rod diameter scheme are developed. And experiments are done to find the best scheme.For the sealing structure, it uses bilateral self-clamped sealing manner, to meet the design requirements. Syringe uses eccentric inlet setting, in order to reduce the generation of bubbles, and the bubble holes can improve sampling accuracy.3. Cleaning system fluid path uses the pressure relief valve, can effectively prevent the sampling needle suck phenomenon.4.Using comparative analysis method to select the materials of several major components for sophisticated sampling system designed by this thesis.5. According to the control requirements for positioning of this precision sampling system, we design the hardware system, control the number of steps and direction for stepper motor, and also control solenoid valve switches of cleaning system.We make the above design into finished products, and uses existing experimental apparatus of Neusoft Andre Medical Technology Co., Ltd. to carry out experiments, including the experiments for sophisticated sampling system, and precision experiments for the complete machine clinical projects. The experimental results show that:the system can meet the function, accuracy, and repeatability requirements of the design proposed.