Mechanism of ultrasonic atomization using a multipinhole plate.

Abstract

Modifying ink-jet techniques used for character displays, an atomizer with a multipinhole plate is trial-made. The pinhole plate with seven pinholes of 80μm in diameter is piezoelectrically driven at 34.4 kHz by a bimorph structure. Due to the intrinsic nature of the technique, important merits such as the uniform diameter of the atomized droplets, easiness of changing the diameter and of control of the atomizing rate may be expected. Employing the trial-made atomizer, the principle and physical properties of the ultrasonic atomization are experimentally studied. The displacement amplitude distribution of the plate, threshold pressure of atomization, phase of ejection, diameter and amount of droplets as a function of applied voltage are measured to make clear the physical properties of the technique. As a result of experiments, it is made clear that the surface tension of the liquid acts as a valve and that the atomizer has a self-acting liquid supply itself and does not need any pumping apparatus.