Design of valveless type piezoelectric pump for micro-fluid devices

The operation principle of travelling wave rotary type ultrasonic motor can be applied to fluidic transfer mechanism of micro-pump successfully. In this paper, we propose a novel type valveless micro-pump that uses extensional vibration mode of travelling wave as a volume transporting means. The proposed pump is consisted of coaxial cylindrical shells that joined piezoelectric ceramic ring and metal body respectively. To confirm the actuation mechanism of proposed pump model, a numerical simulation analysis on the proposed model was implemented. In accordance with the variation of exciting wave mode and pump body dimension, we analyzed the vibration displacement characteristics if proposed model, determined the optimal design condition, fabricated the prototype pump from the analysis results and evaluated its performance. The maximum flow rate was about 580[μl/min] and the highest back pressure was 0.85[kPa] at 120[Vrms] input voltage. We confirmed that peristaltic motion of piezoelectric actuator was able to be applied to the fluid transferring mechanism of valveless type micro pump effectively through this research.