a method introduces additives into flowing or fluidised media . the spatially predetermined position of the additives in the flowing material , also called fluid bed , is obtained by controlling the pulsating injection , the introduction and exact dosing of additives , that is hardeners , dyes , gas producers and softener for instance , into a liquid plastic stream or metal stream for instance , or the fluid bed of bulk material , such as powder , granules and pellets , is carried out by means of an injector . the invention is used in melting units , in hot channel systems , in tools , componens of tools and injection moulding machines , extruders , injection moulding , pelleting , burner and injection arrangements . the nozzle needle of at least one nozzle , respectively , is variable and highly precisely moved for the introduction by means of a device and in such a way that additive is dosed exactly in relation to the volume flow of the medium and that a pulsating stream is injected into the medium flowing past , by means of at least one well - aimed nozzle opening . the additives are dosed by means of a pressure that can be variably adjusted by pulse width and pulse frequency . the desired homogenous distribution is obtained by the penetrating injection jet during compounding .