Abstract: A device for introducing additive fluids to a primary fluid is characterized by a body having a central bore for flow therethrough of a stream of primary fluid, and a plurality of fluid flow channels in the body. Each channel extends between an inlet to the channel for connection to an associated supply of additive fluid and a plurality of outlet orifices from the channel that open into a surface of the body around and outside of an exit from the central bore. Additive fluid is emitted from the outlet orifices in a direction ranging from the additive fluid being directed generally parallel to a stream of primary fluid exiting the central bore to the additive fluid being directed toward and against the stream of primary fluid.