Technique for producing uniform small droplets by capillary waves excited in a small meniscus

The vibration caused by tapping a small liquid-filled glass capillary causes small droplets to be ejected from the meniscus in its open end. This phenomenon serves as the basis for an apparatus capable of producing uniform water droplets in the size range from 3–150 μm diameter. The electric charge of the droplets can be controlled by electrostatic induction at their point of formation.