Method for freeze-drying of e.g. goods, packed in semi-gas permeable package cover in form of air balloon in food-stuff industry, involves partially radiating goods with microwaves with constant energy under movement of drum

摘要

The method involves providing semi-gas permeable goods (6) that are packed in a package cover to be dried and frozen, in a drum (12) in a vacuum container (11). The vacuum container is held at free selectable cooling temperature of the goods to be dried. The drum is supported in a rotatable manner around a horizontal rotation axis. The goods are dried by lowering pressure in the container below a triple point of water at cooling temperature. The goods are partially radiated with microwaves with constant energy and/or power under to and fro movement of the drum around a rotation axis. An independent claim is also included for a vacuum dry system for freeze-drying of lumpy, powder type or granulate shaped goods that are packed in a semi-gas permeable package cover.