Development of a novel valve-based piezoelectric ultrasonic pump using a Langevin vibrator

Abstract In this study, a new principle valve-based piezoelectric ultrasonic pump (VPUP) consisting of a Langevin vibrator, compound ultrasonic horn (CUH) and valve was designed, fabricated and tested. The Langevin vibrator and CUH are cylindrical structures with a through-hole, which serves as a flow channel and a chamber. The valve is made of titanium alloy and fabricated by femtosecond laser direct writing technology. It has two types of cross-sectional shapes: bridge type (Valve-1) and double-bridge type (Valve-2). A model diagram of the pumping principle of the VPUP illustrates that the pumping principle is divided into two processes: stepping and dripping. Liquid shear and surface tension play important roles in liquid transport. In this study, the dripping process of liquid was filmed. Two VPUP prototypes respectively equipped with Valve-1 (VPUP-1) and Valve-2 (VPUP-2) were fabricated. Experimental results showed that the flow rate of VPUP-2 was about 125% of that of VPUP-1, which verified the correctness of the Valve-2 for more favourable stepping and dripping processes. VPUP-2 produced a maximum flow rate of 5.562 ml min ⁻¹ under sinusoidal excitation at 440 V _pp and 35.783 kHz.