Research and development on the valve-less piezoelectric pump with unsymmetrical corrugation chamber bottom

The valve-less piezoelectric pump is more suitable for minimization and microminiaturization than the valve piezoelectric pump, especially for the Microelectromechanical System (MEMS) because of its simple structure. However, in order to control the flow direction of the fluid through the pump, some assembles have to be attached outside the chamber. And it is no doubt that these assembles will take some space and hinder its further microminiaturization. In this paper, a novel valve-less piezoelectric pump with unsymmetrical corrugation chamber bottom (UCCB) is presented. It ingeniously takes advantage of the space of the chamber by developing its bottom into a unsymmetrical corrugation shape along the axis of the inlet and outlet. As a result, a series of diffuse pipes and nozzle pipes (or wedge-shaped pipes), which substitute the regular diffuse/nozzle elements fitted outside the chamber, are alternatively formed between the unsymmetrical corrugation chamber bottom (UCCB) and the piezoelectric vibrator. The piezoelectric vibrator is opposite to the UCCB. And these diffuse pipes and nozzle pipes are able to force the fluid in the chamber to flow along a single direction when the pump works. And then the mathematic model is established to present the relationship between the mean energy loss and the now rate of the pump. Basing on the mathematic model, the theory on the pump working is analysed. Finally, a real UCCB valve-less piezoelectric pump is manufactured, and the test with it is carried out to verify the theory above-mentioned.