Design of a Valveless Type Piezoelectric Pump for Micro-Fluid Devices

Abstract

The operation principle of a traveling wave rotary type ultrasonic motor can be successfully applied to the fluidic transfer mechanism of the micro-pump. This paper proposes an innovative valveless micro-pump type that uses an extensional vibration mode of a traveling wave as a volume transportation means. The proposed pump consists of coaxial cylindrical shells that join the piezoelectric ceramic ring and metal body, respectively. In order to confirm the actuation mechanism of the proposed pump model, a numerical simulation analysis was implemented. In accordance with the variations in the exciting wave mode and pump body dimension, we analyzed the vibration displacement characteristics of the proposed model, determined the optimal design condition, fabricated the prototype pump from the analysis results and evaluated its performance. The maximum flow rate was approximately 595 μL/min and the highest back pressure was 0.88 kPa at an input voltage of 130 Vrms. We confirmed that the peristaltic motion of the piezoelectric actuator was effectively applied to the fluid transfer mechanism of the valveless type micro pump throughout this research.