| abstract |
A volume sensor-free microdosing device comprises a pressure chamber which is at least partly delimited by a displacer, an actuating device for actuating the displacer, the volume of the pressure chamber being adapted to the changed by actuating the displacer, a media reservoir which is in fluid communication with the pressure chamber, an outlet opening which is in fluid communication with the pressure chamber, and a control mechanism. The control mechanism drives the microdosing device in such a way that a small change of volume of the pressure chamber volume is effected per unit time by a movement of the displacer from a first position to a predetermined second position, the second position of the displacer defining a larger volume of the pressure chamber than the first position, so as to suck a fluid volume into the pressure chamber, and that, in a second phase, a large volume change of the pressure chamber volume is effected per unit time by a movement of the displacer from the second position to the first position, so as to eject a defined fluid volume from the outlet opening in this way. |