Theoretical And Experimental Research Of Piezoelectric Insulin Pump

Piezoelectric insulin pump use PZT micro-pump as conveying device, byadjusting the voltage, frequency, pulse number of the input electric signal to achieveprecision control. The insulin pump is to replace the artificial injection according tothe human body blood glucose change through regular insulin infusion to human bodyto treat diabetes, therefore, it must be real-time monitoring and accurate infusion, atthe same time, in order to meet the popularization, insulin pump should has low cost,small size, convenient operation, etc.. Previous research and products, due to drivingmode, production technology, processing costs and other constraints, inevitablyproduced some defects, this paper based on predecessors, using piezoelectric drive,and through reasonable material, structure, process design of piezoelectric pump,combined with the analysis of a large number of tests, to make the piezoelectric driveinsulin pump prototype for usage requirements.Combined with the technical specification of national high-tech research anddevelopment program (namely863Program):"micro-system of blood glucosedetection and insulin injection"(No.2011AA040406) to carry out research, this paperbased on micro piezoelectric pump, analysis different structural parameters ofpiezoelectric pump and working principle of the system in detail, and provide atheoretical basis for the design and application of insulin pump. The main researchcontents are as follows:1. piezoelectric vibrator characteristicsThe piezoelectric vibrator is the power source of piezoelectric pump, usingpiezoelectric oscillator equivalent concentrated force model, analysis the limit flowand limit pressure of piezoelectric vibrator can provide. Through the establishment ofoscillator theory bending model, find out the influence of parameters of piezoelectricoscillator output displacement, and optimize the substrate and ceramic radius ratio bytheoretical analysis.2. characteristics of valveCheck valve is the element of the control flow of the piezoelectric pump, through theestablishment of dynamic model of valve with bubble existing, analyses the influence of parameters of valve vibration state. The comparative study and experiment of valveof different shapes were affected by bubbles shows that when the stiffness of valve islarger and the shape of valve is relatively smoother, piezoelectric pump were affectedby the bubble is small, and as a basis for valve selection and optimization. Discuss thestiffness variable settings of the valve and its effects to the piezoelectric pump outputflow rate and pressure in theory.3. analysis and experiment of piezoelectric pump parametersOn the basis of the theory of fluid flow, analysis and experiment on piezoelectricpump assembly gap due to the different assembly ways, and obtain a relationshipcurve of assembly gap and output pressure. Discuss the external load effect on theoutput performance of the pumps, including the entrance tube length, mediumviscosity and temperature. Finally, the factors affecting self-priming of piezoelectricpump were studied, it is pointed out that the initial volume of the pump chamber andthe energy transfer efficiency are the two key factors, in the structural design ofpiezoelectric pump, it should be appropriate to reduce the initial volume and improvethe vibrator to the kinetic energy of the fluid energy transfer efficiency.4. design and production of insulin pumpThe insulin pump which is studied in this paper, including mechanical unit andelectronic control unit, the mechanical unit consists of three parts: a PZT micro-pump,sachets and shell. The PZT micro-pump is the main part of mechanical unit,completed by CNC technology, the sachets is made by PE thin films using highfrequency hot pressing technology package, the shell is made of ABS produced by3Dprinting technology, housing design should meet encapsulation, technology,practicality, aesthetics and other requirements. Electronic control unit provides thedriving signal for the piezoelectric pump, waveform selection of sine wave, powersupply to output accurate, stable and easy to adjust. Formulate performance indicatorsof insulin pump, and test to verification.