Theoretical And Experimental Research On Jetting Piezoelectric Pump Without Valve

The piezoelectric pump, using the deflection of piezoelectric diaphragm (PZT actuator)to transmit fluid, is a new-type fluidic device. It is an important part and researching focus inMicroflow Systems. There are more than ten counties and regions all over the world in whichthere are the research institutions of the piezoelectric pump. With many merits such as simplestructure, small body, no interfere of electromagnetism and good output ability under lowapplied voltage etc, the piezoelectric pump has very extensive application prospects in thefields of chemical analysis, medical treatment, pharmacy and bioengineering etc. Currentresearch give most attention to miniature pump, and various small pumps with valve havebeen made in the Japanese Measure Equipment Company and sold in the market. It can beused for blood's transport, cleaning of small parts, smearing of glues and chemistry analysisetc. At present, the Japanese NEC company declares having develop the first miniwater-cooling module in the world used for the notebook PC and driven by piezoelectric (PZT)pump.This paper studies systemically on jetting piezoelectric pump without valve. It hasmany merits such as simple structure, small body, low noise, low electricity consumption andso on. The jetting height of the jetting piezoelectric pump without valve is mainly affected bysuch factors as the piezoelectric bimorph, pressurizing way of the PZT bimorph, actuatingvoltage applied on the pump, working frequency of the pump, inlet and outlet caliber and theshape of pump chamber. This text discussed the circumstance when single factor changes, andtentative research on the impact produced by two factors together has been carried on, whichare as follows:1. Analysis and experiments on the piezoelectric bimorphThe piezoelectric bimorph is the key part of the pump, so to find out itsstructure and working characters has the very important significance on improvingthe output performance of the pumps. In this chapter, the piezoelectric effect,piezoelectric materials and the structure of piezoelectric bimorph are presented.The vibration equation of the PZT bimorph is educed by using the sheet vibrationtheory and the related piezoelectric knowledge, and the central displacementformula is worked out.2. Research on the characters of jetting piezoelectric pumpwithout valveThe piezoelectric actuation is selected for the pump with the comprehensiveanalysis of the structures and characteristics of all kinds of micropuimps. The PZTelement, with the series merits such as high resolving, sharp response,free-friction and fray, low consuming of power, resistance to magnetic influenceand low requirement of working environment and so on, becomes the preferredactuated element in the leading scientific field.Qualitative theoretical analysis on such factors as piezoelectric bimorph, inlet and outletcaliber of pump, the work frequency, driving voltage, the pressurize way of pump, the shapeof chamber etc. And the formula of jetting height is conclude.Experimental sample is made using the selected piezoelectric bimorph , which has thefollow structurePiezoelectric pump with different inlet and outlet calibers are made. Withexperimental tests, such conclusions are drawn.1. With the test on pumps of different shapes of chamber, different inlet and outletcalibers, jetting height is proved linear to applied voltage. The higher the voltage is, the biggeris the jetting height.2. Piezoelectric pump can work only in a fixed frequency range which called functionfrequency range. It is influenced by the shape of chamber, inlet and outlet calibers, power andpiezoelectric bimorph etc. The only has an extremum within the scope of work frequency.The small taper pump has a narrow work frequency scope and a great jetting height. Oval...