GB1257985A - - Google Patents

Abstract

1,257,985. Freeze-drying apparatus. GENERAL FOODS CORP. 28 April, 1969 [26 April, 1968], No. 21631/69. Heading F4G. In a freeze-drying apparatus, vertical fixed heating elements 3, extending longitudinally of a vacuum chamber 1, are interleaved with movable receptacles 8 carrying the material to be dried. The receptacles 8 may be joined at the top by a portion 9 mounted on wheels 10 running on rails 11 above the heating elements 3. Alternatively the receptacles may be movable individually in troughs (18, 19, Fig. 3, not shown), or they may have wheels at each corner bearing against the plates containing the heating elements (Fig. 5, not shown). The receptacles preferably have perforations (13) to allow vapour to escape, or are made from meshed web. The receptacle has a trap-like bottom 17 to facilitate discharge of the dried material, which may be for example coffee, tea or small pieces of vegetable, meat or fruit. The heating elements may be electric heaters or tubes containing heated liquids or gases or steam, and they may extend the whole length of the chamber or there may be consecutive sets of adjacent elements producing different temperature zones along the chamber (Fig. 5).