Abstract A fluid energy drying mill wherein the material to be dried is a liquid slurry of solid particles or of solids in solution. The slurry, upon being fed into the mill is immediately atomized and flash-dried, the atomization being accomplished by high pressure, high velocity gaseous fluid jets, while the flash-drying is effected by very hot, low pressure, gaseous fluid jets. The hot gaseous fluid jets comprise a plurality of gaseous fluid streams which enter from at least four different sides surrounding the feed inlet and converge at a focal point downstream of the inlet whereby the hot gaseous fluid both encompasses the fed material and concentrates its heat energy in the path of the fed material. The flash-dried particles are then centrifugally passed through the curved portion of the mill and centrifugally exhausted from the mill during their passage. Optionally, by-pass ducts may be provided between the downstack portion of the mill and the inlet chamber where atomization and flash-drying takes place whereby vapors from the downstack are used to break any vacuum in the inlet chamber and may also be used as a tempering means to avoid case hardening of the particles.
The mill of claim 1 wherein said feed inlet, said atomizing nozzle and said cleaning nozzle are longitudinally adjustable.
Claim 2
Dependent Claim
223 words
A drying mill comprising an inlet chamber having a front end and a rear end, a generally arcuate tubular portion extending from the rear end of said inlet chamber and having an exhaust duct intermediate thereof and a return section connected to said inlet chamber adjacent the front end thereof, at least one conveyor nozzle entering said inlet chamber at an angle tangential to the longitudinal axis of said inlet chamber, said conveyor nozzle being connected to a source of hot, low pressure gaseous fluid, a feed inlet at the front end of said inlet chamber, said feed inlet being connected to a source of solids containing slurry, atomizing means in said inlet chamber for atomizing the slurry issuing from said feed inlet, and a plurality of enveloping nozzles positioned radially outward of said inlet nozzle and atomizing means and inclined toward each other whereby they act to direct intersecting streams of hot, low pressure gaseous fluid within said inlet chamber toward a focal point intermediate the front and rear ends of said inlet chamber and rearwardly of said feed inlet and atomizing means, said enveloping nozzles being connected to a source of hot, low pressure gaseous fluid, and at least one by-pass duct connected between said return section and said inlet chamber at a position adjacent said feed inlet and atomizing means.
Claim 3
Independent Claim
106 words
A method of drying particles in a slurry which comprises passing the slurry into the inlet chamber of a generally arcuate mill, atomizing the slurry as it enters said inlet chamber, enveloping the atomized particles with angularly directed streams of hot gaseous fluid while directing said hot gaseous fluid toward a focal point rearwardly of the entering slurry and while propelling the atomized particles toward said focal point, centrifugally propelling the resultant particles around an arcuate path and through an exhaust duct positioned in said arcuate path, and by-passing gaseous fluid from said arcuate path into a position adjacent the entering slurry as it is atomized.