Elastic string check valves can efficiently heighten the piezoelectric pump's working frequency

This study presents the design, analysis, fabrication process and experimental results of elastic string check valves for high frequency and high flow rate piezoelectric pumps. The moving part of the check valve is elastic rubber strings. Analysis revealed that the rubber string valve could exhibit high working frequency and is beneficial to construct large outflow pumps. A separable micropump was designed for testing frequency performance of the string valve. Experimental results demonstrated that the flow rate almost increased linearly with driving frequency below 1 kHz despite the first resonant frequency of the rubber string occurring at only 488 Hz. The maximum flow rate of water was 67.1 mL/min when the micropump was driven with a sinusoidal voltage of 170 Vpp at 1 kHz.