Drying and gas or vapor contact with solids – Process – Congealing or thickening
Patent
1999-05-04
2000-11-28
Gravini, Stephen
Drying and gas or vapor contact with solids
Process
Congealing or thickening
34367, 34373, 34394, 34430, 34218, 34227, F26B 506
Patent
active
061517984
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a process and an apparatus for spray drying or spray cooling, particularly for spray drying liquids containing solid materials dissolved and/or suspended therein or for spray cooling congealable liquids.
Apparatuses for spray drying or spray cooling comprising a spray drying or spray cooling chamber, means for atomizing a feed stream into said spray drying or spray cooling chamber, means for bringing a drying or cooling gas into contact with said atomized feed stream in said chamber so as to provide partially dried or congealed particles, a screen means having a movable surface for collecting said partially dried or congealed particles so as to form a product layer, means for drawing drying or cooling gas through said product layer and said screen means in one or more drying or cooling stages, a pressure difference thereby being applied over the screen means and the product layer, and means for moving said movable surface are known in the art.
For instance, spray drying apparatuses of this kind and processes for spray drying, which can be carried out in such apparatuses, are known from U.S. Pat. Nos. 3,520,066, 3,615,723, 3,741,273 and 4,351,849, the contents of which are incorporated herein by reference. A commercially used process of this kind is the so-called Filtermat.RTM. process.
Also apparatuses and processes, wherein a coating or similar treatment is carried out concurrently with the spray drying by means of bringing the atomized feed stream into contact with an atomized stream of a coating substance, or the like, in the spray drying chamber are known, cf. e.g. U.S. Pat. No. 4,784,878, the contents of which are incorporated herein by reference.
In carrying out a process of the abovementioned kind, the feed stream is atomized using such means as nozzle atomizers (e.g. pressure nozzles or fluid-atomizing nozzles) or rotary atomizers (e.g. atomizer wheels or atomizer discs) and brought into contact with a stream of drying or cooling gas (laminar and/or turbulent) and possibly a coating substance and/or other additive(s), so as to obtain partially dried or congealed particles, which are collected as a product layer of at least partially agglomerated, particles on the movable surface of the screen means, such as a perforated drum, a conveyor belt made from wire screen or a woven filter web, and subjected to further drying and/or cooling by drawing drying or cooling gas through the product layer and the screen means. The further drying or cooling may take place in one or more stages, the first one normally being carried out in connection with the collection of the particles on the screen means in the spray drying or spray cooling chamber, whereby drying or cooling gas is drawn through the product layer and the screen means. By means of the movable surface of the screen means, the collected product layer may be moved out of the spray drying or spray cooling chamber during the drying or cooling, or batchwise after a desired degree of drying or cooling has been obtained. Possible further drying and/or cooling steps may be carried out in further stages inside and/or outside the spray drying or spray cooling chamber, whereby the movable surface of the screen means can be used for moving the product layer from one stage to another.
With the purpose of achieving an improved distribution of the particles in the product layer, particularly with regard to achievement of a layer of adequate structure and even thickness in a direction transversal to the direction of movement of the movable surface, when using large or cylindrical drying chambers, it has been proposed to provide a turbulent zone between the chamber and the conveyor belt, cf. WO-A-89/09372. This solution more or less solves the problem of creating a layer of settled particles with an even thickness in the transverse direction of the conveyor belt, does, however, create other problems as, due to a relatively high gas velocity and because of introduced supplementary process air, the particles settle as a compact layer presentin
REFERENCES:
patent: Re22090 (1942-05-01), Powell
patent: 3520066 (1970-07-01), Meade
patent: 3525163 (1970-08-01), Boylan et al.
patent: 3615723 (1971-10-01), Meade
patent: 3741273 (1973-06-01), Meade
patent: 4116756 (1978-09-01), Quee
patent: 4351849 (1982-09-01), Meade
patent: 4784878 (1988-11-01), Haak
patent: 5595282 (1997-01-01), Mokler
Gravini Stephen
Joyce Andrea M.
Niro A/S
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