摘要 |
<p>In a device for ejecting small amounts of a liquid material having accurately defined volumes from a chamber (1), the chamber has a nozzle aperture (7) and a rod (9) is mounted in or attached to a wall of the chamber (1), so that an end surface (11) of the rod is located opposite and at a small distance of the nozzle aperture (7). A driving device is coupled to the rod (9) for displacing the end surface (11) forwards and backwards inside the chamber with a very small stroke, with a high acceleration and a large force, so that a pressure wave is formed and propagates in the material in the chamber (1). The pressure wave then ejects material out of the nozzle aperture (7).</p> |