A LOW COST PIEZOELECTRIC VALVE-LESS DIAPHRAGM PUMP

Flow pumps act as important devices in areas as Bioengineering, Medicine, Pharmacy, among other areas of Engineering. Principles for pumping fluids based on piezoelectric actuators have been studied in the Department of Mechatronic and Mechanical Engineering of University of Sao Paulo, that allow the construction of small flow pumps, in other words, pumps for displacement of small fluid volumes with low power consumption. The present work studies valve-less piezoelectric diaphragm pumps for flow generation. The piezoelectric diaphragm flow pump uses a piezoelectric ceramic as actuator to move a membrane (diaphragm) up and down as a piston. Consequently, there is a sequence of increase and decrease in the chamber volume that will force the fluid in and out of the pump. The direction of the flow is guaranteed by nozzle/diffuser elements that privilege the flow in just one pumping direction. The main objective of this work is the study of a methodology to develop a low cost valve-less piezoelectric diaphragm flow pump. A complete cycle of pump development is conducted in this work, consisting in designing, manufacturing, and experimental characterization steps. In the design step, sensitivity studies are performed using computational simulations through the Finite Element Method (FEM) to analyze effects of geometric and assembly parameter variation in the pump behavior. Moreover, the CFD simulations are performed to study the fluid flow inside the pump, as well as the performance of the designed nozzle/diffuser elements. The prototype manufacturing is guided by computational simulations. Low cost machining and electro-erosion are used as manufacturing processes. Pressure and flow characterization experimental tests are conducted and comparisons among numerical and experimental results are made to validate the computational results, improving the accuracy of the implemented models.

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