Pipette device with throttle position in the pipette channel

摘要

The device (10) has a pipette duct (12) whose throttle point (42) is arranged fluid-mechanically between a metering liquid receptacle (38) and a pressure change device (40). The point is being dimensioned in such a way that ratio of flow resistance (R1) of a pipette opening (36) for dispensed metering liquid to flow resistance (R2) of the throttle point for working fluid is less than 0.5. Flow resistances of respective tapering of cross-section of flow are being calculated under consideration of product of viscosity of the working fluid and the metering liquid.