Research On Design Theories And Experiments Of Piezoelectric Resonantly Driven Diaphragm Pump

In recent years,as an important species of fluid pump, diaphragm pump has widelyapplication in pharmaceutical and biotech, fine chemical, aerospace,micro-electromechanical systems and show good prospects for development,which are metin the miniaturization、low output performance requirements.At present,there are two maintype of diaphragm pump, piezoelectric diaphragm pump driven by piezoelectric vibratorand electromagnetic diaphragm pump driven by motor cam mechanism.The drive capacityof traditional piezoelectric air pump is much lower than the liquid piezoelectric pump ofthe same volume, but also problems of piezoelectric wafer heating, easily broken, and noisewhich seriously affect the life and reliability work. Electromagnetic diaphragm pump hasproblems of complex structure, high cost, noise and other issues.Combing with thecharacteristics of existing piezoelectric pump and the system resonance technology, thispaper puts forward a new kind of piezoelectric resonant diaphragm pump driven by thediaphragm resonance with piezoelectric vibration excitation, researchs the basic principleand composition method and designs prototype for testing.The work is a part of StateNatural Sciences Foundation Monumental Projects (Project No.511175213).Specificcontent as follows:1. Analyzed the equilibrium conditions of the circular piezoelectric vibrator whichpiezoelectric resonant pump used and the bending deformation deflection. This paperobtained the vibration mode of multistage modal piezoelectric vibrator through establishingthe FEM model and solved the deflection formula of the piezoelectric vibrator centerthrough the analytical method.Through the experiment test, relationship of the drivingvoltage and the annular piezoelectric vibrator center deflection was obtained. Finally, impedance characteristics and natural frequency of the piezoelectric vibrator weremeasured by impedance analysis.2. It described respectively the principle of operation for the two parts of piezoelectricresonance pump: the vibration unit and pumping unit. It also established the dynamicsmodel, calculated the stiffness for the structure of the vibration unit, and calculated themagnification of resonance system. In the analysis of the pumping unit, the diaphragmdeflection of diaphragm and the pump output flow calculation formula for pumping fluidwere deduced. Finally the resonance frequency of piezoelectric resonance vibration andvibration displacement were took experimental measurements.3. According to the circular rensonance plate spring in piezoelectric resonance pumpnot easy to change, piezoelectric resonance pump of magnetic spring is designed using thecharacteristics of the variable stiffness of magnetic spring. And through the establishmentof mathematical model of magnetic spring, it achieved the relation between the axialmagnetic spring stiffness and the axial spacing. Furthermore, the magnetic spring axialforce was measured by using the electronic scale and carved the machine surface of test rig.Second, it described the principle of operation for magnetic spring type piezoelectricresonance pump, and its dynamics model was established. From the calculation results, itcan be obtained that adjusting the magnetic spring axial spacing can change the resonancefrequency of resonance pump. Through taking FEM model of the magnetic springresonance pump, we can know that, when vibration unit in first-order modal, the center ofmass position amplitude is the largest. Finally, it took the structure design for the magneticspring piezoelectric resonance pump and made a prototype, and carried on the resonancefrequency and the vibration displacement measurement for vibration unit on the designprototype, then its vibration amplitude ratio were measured at the end.4. Taking the piezoelectric resonance pump and magnetic spring type piezoelectricresonance pump as the research objects, this paper carried two works. In the first part,experiment test for driving different viscosity of the liquid. First of all, a test bench forliquid flow measurement was built, then selected properties of stability which almost novolatilization, and also make no pollution to the environment as a proportion for solution ofglycerol test. Through the experimental method, it made the optimal selection of the structure parameters of resonance pump vibration unit and pumping unit. And two kinds ofresonance to the maximum pump output flow rate the pressure were obtained. The secondpart is aimed at conveying experiment for gas. Construct the experimental platform fordelivering gas, then took the conveying experiment respectively for the piezoelectricresonance pump and the magnetic spring type piezoelectric resonance pump.In addition,the flow difference between pumping liquid and gas under the same working conditions ofthe resonance pump were analyzed and explained.5. According to the characteristics of operation for piezoelectric resonance pump, itdesigned the drive controller of the resonance pump which mainly includes the overallstructure of the controller design, the selection of core processors and inverter type drivecircuit.