A new cymbal-shaped high power microactuator for nebulizer application

Inhalation therapy is being applied in the home care field to a gradually increasing degree, and therefore two issues of great importance are the convenience and portability of medical devices. Hence, this paper presents a novel cymbal-shaped high power microactuator (CHPM) that includes a ring-type piezoelectric ceramics and a cymbal-shaped micro nozzle plate. The latter can focus energy on the center of the nozzle plate and induce a large force, which provides the cymbal-shaped microactuator with high power to spray medical solutions of high-viscosity produce ultra-fine droplets and increase the atomization rate. In this research, the CHPM can reduce liquids to droplets of an ultra-fine size distribution (Mass Median Aerodynamic Diameter, MMAD), increasing the nebulizing rate and enabling the spraying of high-viscosity fluids (lavender oil, cP > 3.5). The ultra-fine droplets were of a MMAD of less than 4.07 μm at 127.89 kHz and the atomization rate was 0.5 mL/min. The drive voltage of CHPM was only 3 V, and the power consumption only one-tenth that of ultrasonic atomizers at 1.2 W. The simulation and experiments carried out in this study proved that the droplets are much smaller than those produced by current conventional devices. Therefore, the CHPM is suitable for use in the development of a convenient and portable inhalation therapy device.