Patent ID: 8778281

Claim:
A sample preparation dosing unit for liquid dosing from a supply to a target in a sample preparation device, comprising: an inlet port for fluidically coupling the sample preparation dosing unit to the supply; an outlet port for fluidically coupling the sample preparation dosing unit to the target; a pump, fluidically arranged between the inlet port and the outlet port; an outlet flow restrictor with an outlet flow resistance, fluidically arranged between an outlet of the pump and the outlet port; and a control arrangement with a branch, a control valve and a control flow restrictor with a control flow resistance, such that the flow at the outlet of the pump is divided by the branch into an outlet flow through the outlet flow restrictor and into a control flow through the control flow restrictor, and the control flow downstream of the control flow restrictor is fed, depending on the state of the control valve either into the outlet port such that it merges with the outlet flow downstream of the outlet flow restrictor, or into a bypass conduit.