PIEZO ELECTRIC ACTUATOR DRIVERS

Their working frequencies can be significantly increased, even above 22 kHz, which is the upper-frequency limit of sounds that humans can hear. As there is no frictional wear or sticking effect, valveless pumps have long durability and good reliability. The other strategy is to utilize the change in the height ratio of the upper and lower chambers to induce a pressure difference between the inlet and outlet 19. One strategy is to utilize the synthetic jet effect to manipulate the flow resistance difference of the tube wall to generate a flow 18. There are several approaches to realize PE-based valveless pumping 16, 17. The structures of valveless PE pumps are much simpler than those of valve-based PE pumps. In addition, the valves gradually lose their function due to aging and fatigue, resulting in relatively short durability and poor reliability 15.

PIEZO ELECTRIC ACTUATOR DRIVERS

Therefore, the valve-based PE pumps are only suitable for low-frequency drivers (less than 1 kHz) 14. The hysteresis becomes severer when the pump works at relatively high frequencies, resulting in unstable performance.

Although valve-based PE pumps have a positive effect on controlling the fluid movement direction, there is a phase difference between the opening and closing of the valves and the vibration of the PE actuators. The valve-based PE pumps can be further divided into active valve pumps and passive valve pumps based on the types of valves used. The PE peristaltic pumps have complex structures and rely on multiple vibrators to realize the creep effect in the flow direction.

The continuous development of MEMS technology has led to new strategies for designing PE micropumps 8, and many kinds of structures have been developed, such as pumps with triple vibrators 9 and pumps with direct spray structures 10.īased on their working principles and structures 11, PE micropumps can be classified into piezoelectric peristaltic pumps, valve-based PE pumps, and valveless PE pumps 12, 13. PE micropumps have small sizes, good integrability and low power consumption levels 5, 6, and they have become a popular research topic in industry and academia 7. Similar content being viewed by othersĭriven by strong application prospects in various fields, including medicine, health care 1, 2, microfluidics 3, and microelectronics circuit cooling 4, piezoelectric (PE) micropumps using piezoelectric materials as the driving components have been extensively explored and developed. Results show that performance of the micropump is highly consistent with the numerical analysis with a high flowrate and pressure load, demonstrated its great potential for wearable/portable applications, especially for blood pressure monitoring. Then, a prototype of the piezoelectric micropump is fabricated. The output gas flowrate of the pump is approximately 135 mL/min, and the maximum output pressure exceeds 40 kPa. The maximum vibration amplitude of the piezoelectric actuator reaches ~29.4 μm. The working frequency, vibration mode and displacement of the piezoelectric actuator, the velocity of gas flow, and the volume flowrate of the micropump are analyzed using the finite element analysis method. Herein, we propose a high-flowrate and high-pressure load valveless piezoelectric micropump with dimensions of 16 mm*16 mm*5 mm. However, the electromagnetic effect-based gas pumps normally have large sizes, high levels of noises and high power consumption, thus they are not suitable for wearable/portable applications. Miniaturized gas pumps based on electromagnetic effect have been intensively studied and widely applied in industries.

Piezo electric actuator