The Design Theory And Key Technology Research On The Double Chamber Piezoelectric Insulin Pump

Recently, the insulin pump injection has become the preferred treatment forinsulin injections what generally accepted by the medical profession today, the twoforms of insulin pumps on the market which are both mechanical plunger typemarket structure, using the mode of motor drive and screw driver, limited by thescrew pair tooth pitch and accuracy of the motor movement, are difficult to beregulated precisely In order to meet the high accuracy bolus insulin, cost, size, andother milt-functional requirements, the piezoelectric driven miniature insulin pumpcame into being researchers designed the series arrangement piezoelectric insulinmicro-pump with four cavity and four transducers years ago. However, due to thecomplex structure of the pump, the difficulty of machining and the difficult to carryout production of large quantities, we need to improve their materials and structure.Combined with the technical specification of national high-tech research anddevelopment program (namely863program): Microsystem of Blood GlucoseDetection and Insulin Injection(No.2011AA040406), in the premise ofminiaturization, to explore the whole process of the piezoelectric insulin pumpprototype production through the analysis on all components, system workingprinciples and characteristics of micro-pump; and to study the issues about structureoptimization, production of craft, economy and biocompatibility of piezoelectricinsulin micro-pump prototype, to identify accelerated life test method suitable forthe pump by analyzing the failure modes and failure mechanisms of the piezoelectric insulin micro-pump. The main contents of this paper are given as follows:1.The results show that: in the treatment for diabetes, the effect of insulin pumptherapy was significantly better than traditional multiple daily insulin injections. Theformer can make blood sugar controlled more precise and complications reduced by60%to76%. So far, the insulin pump injection has become the preferred treatmentfor insulin injections what generally accepted by the medical profession. Afterintroducing the development of the insulin pump and the status quo at home andabroad, to meet the high accuracy bolus insulin, cost, size, and othermulti-functional requirements, the piezoelectric driven miniature insulin pump cameinto being.2.Analyzing the piezoelectric ceramic material, the work mode of vibration ofthe piezoelectric transducer and the method of supporting the piezoelectric oscillator,we determine the piezoelectric ceramics of piezoelectric insulin micro-pump is P5,the work mode is LE and the method of supporting is CLAMPED. Then wecalculate the deformation of the piezoelectric transducer substrate and piezoelectricceramic bonding region, the deformation of the remaining area of the metal substrateand the pump cavity deformation amount and preliminary study the bendingdeformation of the piezoelectric oscillator characteristics through the numericalcalculation. The analysis showed that the suitable substrate material of piezoelectrictransducer is copper, the substrate diameter is15mm, the ceramic diameter is10mm,the substrate thickness and the ceramic thickness are both0.1mm and the layerthickness is0.03mm. With the discussion of all kinds of metal and nonmetalmaterials of the piezoelectric pump valve at home and abroad, we determine themicro-valve material is PET. After that we choose the cantilever valve and the wheelvalve as the piezoelectric insulin pump fluid control components and make thetheoretical analysis and optimization select.3.Under the guidance of the basic theory of piezoelectric pump design,combined with traditional insulin pump structure and new design principles of piezoelectric insulin pump, we design the piezoelectric pump structure which isdual-chamber series and manufacture a prototype model of the piezoelectric insulinpump. On the basis of the analysis of the theory, we adjust the parameters of therespective dimensions of the double lumen series piezoelectric insulin pump throughexperiments and make sure the suitable driving voltage is a sinewave,36V and200Hz, the cavity height is0.06mm, the pre-tightening height of valve is0.1mm,thepump inlet and outlet diameter is1.2mm, the thickness of the valve membrane is0.025mm and the match dimensions of the valve plate and the valve hole is1.1mm/0.8mm. Then we draw the curve of the flow rate and output pressure of dualchamber piezoelectric insulin pump versus frequency at the best performance, anddetermine the minimum resolution of the pump output flow is0.01U.4.We need to study its batch processing production to achieve the means ofmicro-fine processing technology and the small quantities, precision machiningpreparation of the piezoelectric insulin pump machine parts. In the process design ofthe processing and assembly of small quantities of piezoelectric pump, it involves thethermoplastic injection molding, laser processing (including laser welding, lasercutting and laser marking), dispensing as well as ultrasonic welding. And then toidentify accelerated life test method suitable for the pump by analyzing the failuremodes and failure mechanisms of the piezoelectric insulin micro-pump.