Structural Design And Dynamic Analysis Of Countercurrent Chromatography Dynamic Balance Experimental Device

Countercurrent chromatograph is widely used in food analysis,drug separation,biological engineering,environmental analysis and other fields.As a large-capacity device,the preparative countercurrent chromatograph has the advantages of large amount of injection and large amount of production.However,with the development of manufacturing technology,people have put forward higher requirements for the performance of countercurrent chromatograph.Previous preparative countercurrent chromatographs are complicated to disassemble the rotor,the whole machine is not easy to maintain,and the balance accuracy of the rotor after dynamic balance is low,which seriously affects the separation and production efficiency of the instrument.To solve the above problems,under the support of the "national major scientific research instrument development" project,a countercurrent chromatography dynamic balance experimental device was designed in this paper,which combined the planetary rotor of preparative chromatograph with the dynamic balance machine,the optimal design of planetary rotor’s balance hole was carried out,and then combined with the optimized planetary mechanism model parameters,the structure of the dynamic balance machine frame was improved.In addition,in order to ensure that the instrument can achieve the research purpose of the subject,the research work of the instrument,such as dynamic modeling and analysis,dynamic characteristics analysis,experimental modal analysis,dynamic balance experiment,etc,was mainly carried out.The main research work and the results of this paper are as follows:(1)Based on the dynamic balance principle and method of rotor,the traditional design structural model of prefabricated balance hole was established,and the parameter selection requirements of traditional prefabricated balance hole design were determined.Based on the planetary rotor,an improved design algorithm of the prefabricated balance hole was proposed,and the influence of residual unbalance of the separation column in the design of the balance hole of the planetary mechanism was analyzed,which provided a theoretical basis for the selection of the rotor radius of the prefabricated balance hole and the size of the balance hole.(2)According to the separation principle of countercurrent chromatograph and the optimal design method of planetary rotor dynamic balance,the structure design of countercurrent chromatograph planetary mechanism was carried out on the premise of meeting the design requirements of the subject.Based on the model parameters of the planetary mechanism that had been designed,the three components of the dynamic balance machine frame,the drive system,the transmission system and the supporting swing frame,were optimized.(3)In order to keep the instrument satisfying the dynamic requirements of balance machine,and get the key parameter inherent frequency which reflects the dynamic characteristics of the balance machine system,the vibration model of the rotor-support system was established,according to the model calculation,a calculation formula for the inherent frequency of the system and the relationship between swing plane displacement and rotor unbalance vibration force were deduced.At the same time,considering that the joint stiffness of the threaded connection has a great influence on the inherent frequency of the system,the joint stiffness algorithm was studied.(4)Using ANSYS Workbench simulation software,the static and modal analysis of the simplified model of the whole machine was carried out,and the stress,deformation,modal pattern diagram and the stiffness value of key parts of the model were obtained.Based on these,combined with the joint stiffness of the threaded connection,the inherent frequency of the system was solved.And based on this,the dynamic characteristics of the whole machine can be judged to meet the design requirements.In addition,in order to get the influence laws of the structural size changes of key parts to the inherent frequency of the system,the influence analysis of the structure parameters to the inherent frequency of the whole machine was carried out.(5)In order to verify the correctness of the dynamic analysis of the rotor-support system vibration model,the whole machine modal analysis of the countercurrent chromatography dynamic balance experimental device was carried out by using the M+P noise and vibration testing system,and the inherent frequency value of the system obtained from the experiment was compared with the calculated inherent frequency value.At the same time,in order to verify that the dynamic balance experimental device designed in this paper has a good balance effect,the dynamic balance experiments of separation column and planetary mechanism were carried out.