Concept for an instant coffee line from evaporator to the vacuum freeze dryer with the Bucher Unipektin Zeodration system
The concentrated product (between 42 to 48 DS) from the evaporator will be fed over the pre-cooler (+5 °C) to the mixer. In the mixing stage, the fresh product and the recycled product will be mixed and feed to the foaming station. The cold and foamed coffee concentrate, with a temperature close to – 5 °C, is fed from the foaming unit by the feeding pump to the freezing tunnel and distributed as an even layer on the surface of the steel belt of the freezing tunnel.
The belt runs through 3 freezing sections each section with a cold air fan. At the belt end the frozen coffee layer is broken in coarse pieces which are conveyed to a mill system. The granulate size is controlled and are separated on a vibration sieve into fine particles for recycling and regular size which are feed. The fines are fed back to the mixing stage where the fine product is mixed again with fresh product and the process starts again.
The regular size of frozen granulate is conveyed to the feed sluice system of the vacuum belt freeze drier.
The vacuum belt drying plant itself consists of the feed sluice system, the vacuum belt freeze dryer (lyophilizator) and the discharge airlock system, as well as the required utilities systems as vacuum and Zeodration adsorption system and heating and cooling system.