A/s Niro Atomizer

Aktieselskabet Niro Atomizer

Jan Pisecky

Ib H Sorensen

Jens Krag

Georg Hans Hauberg

Vagn Westergaard

Soren P Hansen

Arnold N Jensen

Agglomeration is improved in a straight-through spray drying process by adjusting the location for introduction of recycled fine particles to the atomization zone. The fine particles are dispersed in a minor portion of the drying air and adjustment of the location for the introduction of the fine particles is made so as to change the average distance from the wheel to the area where the fine particles meet atomized droplets or partly dried particles. A spray drying apparatus in which the fine particles are recycled through the use of turnable deflectors, telescopic connections or swivel joints which are suitable for achieving the improved agglomeration.

Process and spray drying apparatus for producing stable particle

Hygroscopic powders, especially fat-containing milk products, are cooled by being fludized in cooling air. Dehumidification of the drying air is omitted and overdrying prior to cooling to compensate powder rehumidification during cooling is avoided by using a closed cycle cooling in which the spent cooling air after efficient dust removal and re-cooling is used as cooling and fluidizing air. Substantial energy savings are achieved while product quality is maintained or improved.

Process for cooling hygroscopic powder

An atomizer wheel for use in a spray drying apparatus comprises an interior annular liquid supply chamber, from which a number of substantially radial ejection ducts extends towards the external surface of the wheel through a length constituting a considerable portion of the radius of the wheel. The ducts discharge into a downwardly open annular discharge slit at a comparatively short distance from an external wall connected with a wheel cover and whose inner wall surface forms an axial-symmetrical surface of revolution with a substantially linear generatrix forming an angle of not more than 15.degree. with the axis of revolution. The comparatively steep slit wall ensures together with the large length of the ejection ducts that the liquid is atomized at the outlet of the discharge slit with a considerable downwardly directed axial velocity component so that the spray characteristics resembles those of nozzle atomization but with preservation of the general advantages with respect to flexibility and reliability of operation associated with wheel atomization.

Atomizer wheel for use in a spray drying apparatus

An agglomerated powdery milk product is prepared by spraying a concentrate of milk or a fraction thereof into a stream of drying gas directed against the surface of a fluidized layer of already spray dried particles in a conical chamber, thereby obtaining a favorable interaction. Special parameters including temperatures, rates of streams of drying air and residence time are adjusted to obtain an extensively agglomerated product, high production capacity, improved heat economy, low heat damage of the product, and to make possible an easy spray drying of materials, which have hitherto been regarded as unsuitable for spray drying.

Process for producing an agglomerated powdery milk product

The invention relates to a method for spray drying perishable liquid products such as milk products. The exhaust gas from the spray dryer is passed through a gas scrubber in which at least part of the liquid product to be dried is used as washing liquid before spraying it into the spray drying chamber of the spray dryer. Prior to passing it into the gas scrubber the washing liquid is heated to a pasteurizing temperature by suitable heating means. These heating means may, for example, be adapted to inject hot steam into the flow of washing liquid, or the heating means may be in the form of an evaporator connected to the spray dryer at the upstream side thereof.

Method for spray drying liquid products

Milk or similar liquids are spray dried using a rotary atomizer wheel whereby such a temperature is imparted to the liquid that a violent release of gas and vapor from the liquid takes place in the atomizer wheel, which gas and vapor are removed before the atomization of the liquid. By these means a powder having at high bulk density and a low content of occluded air is obtained. A special atomizer wheel, having two sets of ejection apertures and two intercommunicating supply compartments makes it possible to eject released gas and vapor through one set of apertures and liquid through the other set, whereby reintroduction in the liquid of the released air is prevented. Also an atomizer wheel of this type is provided wherein the two supply compartments are steam-swept.

Spray drying atomizer wheel

Milk or similar liquids are spray-dried into a powder having a considerable residual humidity, using an inlet temperature for the drying gas higher than usual. This spray-dried powder is after-dried in a fluidized bed. The fine particles entrained by the gas leaving the spray-drier and the fluidized bed are separated from said gases and added to the main bulk of powder after the latter has left the spray-drier and if necessary has been dried to such an extent that the fine particles will not stick thereto. A powder having very high bulk density is obtained and the heat economy is improved.

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Tastrup, Denmark

Jan Pisecky