Patent ID: 8656792

Claim:
A pipette device, at least for dispensing metering liquid by increasing the pressure of a working fluid, the pipette device comprising: a metering liquid receptacle designed to be filled, at least in part, with working fluid and having a pipette opening as a first tapering of cross-section of flow, through which metering liquid can be dispensed from the metering liquid receptacle as a function of the pressure of the working fluid; a pressure change device which is designed to change the pressure of the working fluid in the metering liquid receptacle; and a throttle point in a pipette duct designed to be filled with working fluid as a further tapering of cross-section of flow; wherein said throttle point is arranged fluid-mechanically between the metering liquid receptacle and the pressure change device and is dimensioned in such a way that a ratio of a flow resistance of the pipette opening for dispensed metering liquid to a flow resistance of the throttle point for working fluid, which flows through the throttle point when the metering fluid is dispensed, is less than 0.5; and wherein the flow resistances of the respective tapering of cross-section of flow is calculated under consideration of the product of the viscosity of the medium of working fluid and metering liquid associated with the respective tapering of cross-section of flow and the characteristic length of the associated tapering of cross-section of flow, divided by the fourth power of the characteristic dimension of the cross-section of flow of the associated tapering of cross-section of flow.