GB1355192A - Methods for producing agglomerated coffee powder and other powders and apparatus for carrying out the method - Google Patents

Abstract

1355192 Edible agglomerates NIRO ATOMIZER AS 3 Dec 1971 [21 Dec 1970] 60700/70 Heading A2E [Also in Division B5] - Agglomeration of coffee powder, fat-enriched milk powder, or other powder which is difficult to moisten without too much liquid absorption taking place, is achieved by causing the spray-dried powder to drop into the central area of a rotating disc whilst moistening it, as it falls, by means of steam or finely atomized liquid supplied at such a distance above the central area of the disc that substantially all of the powder is moistened before it hits the disc, the powder then being spun off the disc to fall through a chamber wherein unagglomerated powder is separated from the agglomerated which goes into a dryer. The moistening agent may be a liquid with a solid matter content of the same material as that of the powder. An apparatus comprises a chamber 1 in which is axially-mounted a rotating disc 2, above which is arranged a powder inlet tube 4 with supply funnel 3 (Fig. 2). This tube may be telescopic to enable its height above the disc to be adjusted and move then one tube may be provided. At least one inlet nozzle 42 mounted in or near the mouth of the tube 4 provides a conical spray steam or of atomized liquid e.g. by utilising a liquid line 43 and a compressed air line 44. Powder is fed from a silo 9 via a vibrating chute 10 to fall through the inlet tube 4 and be melted as it drops, the air current due to the centrifugal fan action of the disc 2 causing the powder to tend towards the centre of the disc and from a conical heap. As agglomeration takes place the particles are flung off and fall through the chamber into a two screen vibrating sieve 14, fine powder being drawn off by a suction head just above the sieve and connected to a tube 7 by which the powder is returned to the silo. The sieve 14 comprises a coarse upper mesh and fine lower mesh, the fine powder falling through the latter being recycled via the lines 15 and 16 whilst the agglomerated particles are discharged through the outlet 19 into a 3-stage drier 20 at the discharge outlet of which is a further vibration sieve to remove fine powder into recycling line 16, the agglomerated particles being discharged from the outlet 24. Hot air blowers 22, 23'dry the powder and discharge through a cyclone 26 which removes any entrained fine powder. Appropriate dimensions and spacing distances for the powder and liquid inlets are given with preferred speeds of disc rotation, powder supply quantities and moisture content. If the powder is coffee the disc is preferably planar, but if it is a fat-enriched milk powder the disc is preferably upwardly convex.