Research of piezoelectric pump with a vortex linear valve structure

In this article, a piezoelectric pump with vortex shaped linear valve structure (PPVSLVS) is proposed on the basis of characteristics of flexible materials. Changes in the working state conversion between "valve-based" and "valve-less" of the PPVSLVS can be realized by adjusting driving conditions. The principle of the working state conversion between "valve-based" and "valve-less" of the PPVSLVS is elaborated for the design of the structure of the PPVSLVS. The prototype of the PPVSLVS and the piezoelectric pump with cardiac valve-like structure is fabricated by 3D printing technique, and the corresponding experiments are also conducted. The experimental results demonstrate that the PPVSLVS is ascribed to be a valve-less piezoelectric pump when the driving voltage is less than 140V, while the PPVSLVS is ascribed to be a valve-based piezoelectric pump when the driving voltage is above 140V. When the working state of the PPVSLVS is converted from "valve-less" to "valve-based," the pump flow rate of this pump will be changed from one peak to double peak. Simultaneously, when the driving voltage of the pump is 180V at 12Hz, the pump flow rate reaches a maximum value of 44.3 mL/min. Compared with the piezoelectric pump with a cardiac valve-like structure, under the same driving conditions, the pump flow rate of the PPVSLVS is remarkably increased. When the driving frequency is set as 12 and 24Hz, the average pump flow rate is improved by 107% and 21.3%, respectively. The distance between the free ends of the valve will affect the working states and flow rate of the PPVSLVS. This study contributes to the application of piezoelectric pumps in artificial hearts.