Patent ID: 11911757
Assignee: HAMILTON BONADUZ AG
Field: Measurement (Instruments)
Classification: CPC B  G | IPC B

Claim 18:
19. A pipetting apparatus for pulsed pipetting of dosage liquids in small metered volumes of less than 2 μl with the aid of a modifiable-pressure working gas, the pipetting apparatus comprising:
a pipetting conduit at least partly filled with a working gas;
a pipette tip that furnishes a receiving space that is at least partly filled with the working gas, that is pressure-communicating connected to the pipetting conduit, and that is accessible through a pipetting opening, so that by a modification of the pressure of the working gas in the receiving space, a quantity of dosage liquid received in the receiving space is modifiable through the pipetting opening;
a pipetting piston received in the pipetting conduit, movably along the pipetting conduit, for modifying the pressure of the working gas;
a motion drive system for driving the pipetting piston to move along the pipetting conduit;
a control apparatus for applying control to the motion drive system; and
a position detection apparatus for detecting the position of the pipetting piston and for outputting to the control apparatus the position signal representing the position of the pipetting piston,
the control apparatus being configured to apply control to the motion drive system in order to generate a pressure pulse—with respect to a reference pressure which exists in the pipetting conduit immediately before a pipetting operation begins and at which no fluid passes through the pipetting opening—in the pipetting conduit, on the basis of the position signal outputted by the position detection apparatus, in such a way that the position of the pipetting piston during the pulse follows a predefined target pipetting-piston position curve, the duration of the pipetting-piston motion for generation of the pressure pulse not exceeding 35 ms,
wherein the pipetting apparatus is also configured for conventional, non-pulsed aspiration of dosage liquid.