GB1143723A - Apparatus for the continuous freeze-drying of sprinkable materials - Google Patents

Abstract

1,143,723. Freeze drying. KRAUSSMAFFEI A.G. 31 July, 1967 [10 Aug., 1966; 23 June, 1967], No. 34991/67. Heading F4G. [Also in Division B1] Freeze drying apparatus comprises a stack of heated platforms 2 in an evacuated chamber 1, material being introduced at 22 and discharged at 21. The platforms are alternately of larger and smaller diameter with respectively larger and smaller central openings. Paddles 19, 20 on a central shaft 12 sweep the material inwards to the central openings of the larger platforms, where it falls on to the platforms below, and outwards over the edge of the smaller platforms on to the platforms below. The platforms are hollow and are heated by fluid passing through pipes 8, 10, 9. To prevent material from the inlet 22 bouncing over the edge of the top platform, the pipe may have a flexible or pivoted extension or have pivoted baffles (Figs. 3-7, not shown). The inlet 22 is connected through a gate valve to the lower part of a charging chamber (25, Fig. 2, not shown) which has hollow walls (27a) for cooling fluid and comprises a frusto-conical part with a rotary bottom wall (34) carrying a paddle (38a) which sweeps the material into the lower part. A distributing cone (36) upstanding from the bottom wall has radial projections (37) which prevent agglomeration of the material. The outlet 21 discharges into a wheeled bin (40), which may be evacuated prior to use (via connection 47) or filled with inert gas after use (via connection 46).