Abstract: A valve block (1) for a dosing device with an arrangement of piston pipettes (2) or other dosingdevices, includes, on its one face, a pattern of first mouths (15) to be aligned with the arrangement of piston pipettes (2) and, on the opposite face, second mouths (16) each respectively assigned to a first mouth (15). The valve block (1) also includes a plurality of channel systems (20) each with a main connector (23). The valve block (1) has a plurality of plates (10, 11, 12, 13) arranged in a stack. All plates define through holes (14), which are arranged in the pattern of the first mouths (15). At least a part of the plates (11, 12, 13) also have a channel system (20) with channels (21) connected with the main connector (23), wherein the channels (21) form a pattern, which is matched to the pattern of the through holes (14) and which is laterally displaced relative to this pattern.

Abstract: An automated pipetting device has a first driving motor (1) with a spindle (1') to drive a plurality of injection pistons (6) each movable by a piston shaft (7), and a second driving motor (2) that drives a carrier plate (3) with a spindle (2') in a horizontal direction. A plurality of pipette cylinders (5) are carried in the carrier plate (3) which is pressed against a stationary valve plate (4). The valve plate has a duct system (10) with channels (11,12,13) for supplying and removing liquid. Each individual pipette is spring biased so that its outlet region is pressed against the valve plate at openings of the channels and the carrier and pipettes can be moved with the pipette outlets pressed against the valve plate surface. Each pipette has independent means for applying the spring bias.