A device and a method for continuous and adjustable dosage of fluids at low pressure. The invention is self-cleaning and low tech. It consists of a tapering dosage unit in which a filling, which allows fluids to pass in the longitudinal direction of the dosage unit, is inserted. At the outlet end of the dosage unit, a venturi tube is located which clamps the filling and thereby create a nozzle opening that fits the fluids viscosity and the pressure for a given desired dosage. When the dosage unit clogs, a flushing can be obtained by either increasing the pressure of the fluid and thereby forcing a flexible dosage unit to increase the sectional area and allow cleaning or in the same way through a mechanical opening of the dosage unit.
