Valveless Micropumps with One or Two Piezoelectric Buzzers

Valve-less micropumps with one or two piezoelectric buzzers are manufactured and tested. Piezoelectric buzzers are chosen as actuation elements because they are cheap and with high actuation amplitude. The micro-chamber with nozzle and diffuser is fabricated by employing UV photolithography and film mask. A negative photoresistive material, SU8-50, is used as a structure material, and exact angles in the inlet/outlet elements can be obtained. PDMS is chosen to bond different parts of the micropump. The piezoelectric buzzer does have nice actuation amplitude of 40.4 μm after the assembly with the chamber. The results indicate that the micropump with one piezoelectric buzzer has a maximum flow rate of 90.28μl/min when the buzzer is actuated at 100 V and 20 Hz. A maximum backpressure of 50 mm H2O occurs as the buzzer is actuated at 100 V and 30 Hz. For the micropump with two piezoelectric buzzers, it has a maximum flow rate of 165.32 μl/min when the buzzer is actuated at 100 V and 20 Hz and has a maximum backpressure of 84 mm H2O as the buzzer is actuated at 100 V and 30 Hz.