GB1298911A - Improvements in or relating to vibratory conveyor systems - Google Patents

Abstract

1298911 Freeze drying HILLS BROS COFFEE Inc 25 March 1971 7840/71 Heading F4G [Also in Division B8] Frozen particles of coffee extract are freezedried in an evacuated chamber 42. The particles are fed at intervals through a vapour lock (not shown) to a hopper 50 supplying a vibrating feeder 52 and thence to the top deck 54 of a vibrating conveyer comprising four vertically spaced decks 54, 56, 58, 60. The decks are driven by a motor external to the chamber 42 through a flexible shaft 236 rotating pairs of eccentrics 238, 240 which are 180 degrees out of phase and respectively associated with rocker arms 320, 233. The decks 54, 56, 58, 60 are respectively mounted on sets of pairs of flat springs 186, 188, 190, 192 opposed as shown. The result is that the horizontal direction of motion of the decks 54, 60 is the same but their vertical motions are opposed, while the horizontal direction of motion of the decks 56, 58 is the same, but opposed to that of the decks 54, 60, while their vertical motions are also opposed. Each deck, e.g. 54 is made up of a number of overlapping plates 210, so that at their joints 66 the particles turn over in raising from one plate to the next. Each plate 210 is provided with a cooling coil 212 beneath the upper plate surface while the particles are subjected to radiant energy from sources 214 to sublimate the ice content to vapour form. The vapour collects as ice on refrigerated condensers 62 periodically de-iced by surges of warm refrigerating means so that the ice falls to the bottom of the chamber 42 whence it is removed by belt conveyers 76 which pass it to a suitable vapour lock with breaker means 86. The particles pass along the decks 54, 56, 58, 60 in turn and eventually fall into the product hopper 74. Tubular frame 182 supporting the conveyer decks 54, 56, 58, 60 comprises upper and lower members 194, 196 and 198, 200 of hollow construction through which cooling liquid of similar temperature to that passing through the coils 212 is passed to minimize the effect of change in length of the decks 54, 56, 58, 60 due to temperature change.