Design Of A Medical Micro-atomizer Based On Piezoelectric Actuation

With the development of biomedical technology, piezoelectric micro atomizer is widely applied in many fields, and gradually to develop in the direction of intelligence, micro instrumentation and medical treatment. Based on the piezoelectric theory research, micro atomizer structure analysis and ANSYS simulation, designed and manufactured piezoelectric micro atomizer. I set up the experimental platform for inspecting medical micro atomizer the performance parameters, including flow rate and the particle diameter. It's proved that the design of medical micro atomizer conforms to the basic requirement of inhaled medications, details as follows:The research of the characteristics of the piezoelectric materials and the basic theory of piezoelectric, include piezoelectric effect, piezoelectric boundary conditions and piezoelectric four equations.Then the types and applications of piezoelectric materials are respectively introduced, where the polarization of the piezoelectric ceramic materials method and processing technology are explained.After research in the characteristics of medical micro atomizer and performance parameters, the structure and the driving circuit of the medical micro atomizer are designed. By means of analysis the double membranes ceramic piece and vibration model, I understood the natural frequency of the micro atomization piece related to the size of the ceramic plate. The thicker the thickness and the larger the radius, the lower the ceramic plate frequency is. The atomization piece aperture, the resonance frequency factors have important effects on fog particles form.The model is meshed in ANSYS for analyzing the double membranes atomization piece, then statics analysis, modal analysis and harmonic response analysis are proceed. In statics analysis, it is concluded that the atomization piece of Z axis displacement be bound up with driving voltage and the thickness. In modal analysis, it is concluded that the resonance frequency and vibration structure. In harmonic response analysis, it is concluded that the response curve of the frequency and amplitude of micro atomization piece.After designing and manufacturing medical micro atomizer, I set up micro spray system experiment platform for measuring the atomized flow rate and the diameter of the fog particles and design of the driving circuit. By means of atomization flow rate measurement and data analysis, it can be concluded that when spray liquid is pure water, micro atomization piece apertures are 3?m,5/?m,7 ?m, the atomized flow rates are0. 023 g/s,0.042 g/s,0.075 g/s respectively. Atomization flow rate is inversely proportional to the liquid viscosity. The greater the liquid viscosity is, the smaller the atomization flow rate is. Atomization flow rate is proportional to the diameter of micro atomization piece aperture, the larger the aperture radius, the greater the atomization flow rate. In addition, the greater the viscosity of liquid, the smaller flow rate of fluctuations over time. When spray liquid is pure water and the diameter aperture 3 ?m, randomly selected 500 fog particles as the sample. Through the fog particles diameter measurement and data analysis, it is concluded that the quantity of fog particles, diameter between 2?5 ?m, is 347 and account for 69.4%. This result can meet the standard that the particle diameter which can be inhaled into lungs in the inhaled drug. When spray liquid is pure water and the diameter aperture 7 ?m, randomly selected 500 fog particles as the sample. Through the fog particles diameter measurement and data analysis, it is concluded that the quantity of fog particles, diameter between 6?9 ?m, is 418 and account for 83.6%. This result can meet the standard that the particle diameter which can be inhaled into respiratory tract in the inhaled drug. What is said above that demonstrate the design of medical micro atomizer can basically meet the diameter of inhaled medication requirements.