Patent ID: 6942170

Claim:
A nozzle device for mounting through side walls of a fluidized bed jet mill to discharge a composite stream of high velocity fluid for receiving, entraining and delivering particles of material into a grinding chamber of the fluidized bed jet mill for particle to particle collision, said nozzle device having a first end, and a second end pointing towards a central axis of the grinding chamber when mounted through said side walls, and said nozzle device including a plural odd number of nozzle openings for each discharging an individual stream of high velocity fluid that together form said composite stream, each said nozzle opening having a nozzle axis and including: (i) a converging region defined by a first nozzle wall section located towards said first end for converging and accelerating a volume of high pressure fluid into said individual stream of high velocity fluid; (ii) a throat region defined by a second nozzle wall section comprising a point of narrowest diameter of said nozzle opening; (iii) a first expansion region for producing a linear expansion of said volume of high pressure fluid passing through said throat region, said first expansion region including a third nozzle wall section having an increasing radius “r1”, and an increasing length “s1” running from said throat region towards said second end, and said radius r1 and said length s1 being determined such that (dr1/ds1) is a constant; and (iv) a second expansion region for producing a turning expansion and a parallel flow of said volume of high pressure fluid from said first expansion region, said second expansion region including a fourth nozzle wall section having an increasing radius “r2” and an increasing length “s2” significantly greater than the length s1 of the first expansion region and running from said first expansion region towards said second end, and said radius r2 and said length s2 being determined such that (dr2/ds2) is equal to a non-linear function of s2.