Staged rotary mixer

A mixing device for the mixing of two or more liquids comprising a shell body having upstream and downstream ends and an internal cavity, said cavity having a longitudinal axis and substantially circular cross-section, a shaft having an upstream face and a downstream face of substantially circular cross-section, an outer surface and a longitudinal axis which coincides with said longitudinal axis of said internal cavity, said shaft being rotatably housed within said cavity, said shaft having slotted grooves configured along a portion of its outer surface for receiving the liquids to be mixed from inlets located within the shell body, a narrow annular gap region formed between the outer surface of the shaft and the inner surface of the internal cavity in the portion of the shaft containing said slotted grooves such that said liquids tend to smear in said narrow annular gap region, said shaft further having at least one tubular bore extending from the upstream face of said shaft and emanating from the outer surface of said shaft within said narrow annular gap region for the transport of one of said fluids to be mixed from said upstream face of said shaft to said narrow annular gap region, a drive shaft for connection to a suitable device and shaft for rotating said shaft within said internal cavity and said inlets located within said shell body for the introduction of said two or more liquids to be mixed proximate the upstream end of said shell body and a liquid exit means located proximate the downstream end of said shell body for removing said two or more liquids.