Microdosing device for a liquid medium
A microdosing device for a liquid medium includes a dosing compartment and an electrically or electronically activatable vibration unit which can cause at least one contact area of the dosing compartment to vibrate for the delivery of a volume of medium. A medium reservoir is connected to the dosing compartment by at least one flow channel. A manually operable conveyance device for conveying medium to the dosing compartment and/or for conveying medium back from the dosing compartment to the medium reservoir is assigned to the at least one flow channel.
1. Microdosing device for a liquid medium comprising a dosing compartment and an electrically or electronically activatable vibration unit which can cause at least one contact area of the dosing compartment to vibrate for the delivery of a volume of medium and a medium reservoir which is connected to the dosing compartment by means of a first flow channel,
wherein a manually operable mechanical piston pump for conveying medium to the dosing compartment is assigned to said first flow channel,
wherein said first flow channel comprises a mechanical nonreturn valve between said piston pump and the dosing compartment, said nonreturn valve inhibiting back flow of contaminated liquid medium from the dosing compartment to the piston pump, and
wherein a second flow channel branches off from said first flow channel between the nonreturn valve and the dosing compartment to the medium reservoir, said second flow channel having a filter device.
2. Microdosing device according to claim 1 , wherein the mechanical piston pump includes a sensor system and a control unit, the sensor system sensing a filling operation by the mechanical piston pump and passes on associated signals to the control unit which switches the vibration unit on or off according to associated signals from the sensor system.
3. Microdosing device according to claim 1 , wherein a flow cross-section of the first flow channel is many times greater than a flow cross-section of the second flow channel.
4. Microdosing device according to claim 1 , wherein the second flow channel also includes a further nonreturn valve connected in series with the filter device for inhibiting back flow of medium in the medium reservoir to the first flow channel.