Patent ID: 8511516

Claim:
A container cap for metering a base liquid and mixing the base liquid with a diluent to prepare a product, the container cap comprising: a liquid metering duct; a diluent inlet with a diluent duct; a mixing chamber for mixing the base liquid with the diluent; the diluent duct being positioned with respect to the liquid metering duct so that a diluent stream intersects a base liquid stream before or at the mixing chamber; and a liquid pump so constructed and arranged to meter the base liquid in the liquid metering duct and comprising a means for accelerating the speed of the diluent stream, relative to the speed of the diluent at the diluent inlet, in a region where the said diluent and base liquid meet, and the pump comprises a chamber in which a series of rotary elements that collaborate in gearing engagement is housed, each of the rotary elements including a plurality of teeth having a shape complementary to the plurality of teeth of an adjacent rotary element; wherein the container cap is so constructed and arranged to be connected to a container containing the base liquid.