A new automatic process is proposed for manufacturing, filling and evacuating large containers of (square) block-bottom type up to a capacitiy of 100 liters, particularly for milk powder. In addition, an automatic packaging and evacuating machine is proposed for manufacturing such evacuated block-bottom bags. The process is preferably effected while using a thermally processable laminated foil with excellent resistance to high mechanical stress, steam, gas and light permeability, in evacuating chambers operating simultaneously, though preferably discontinuously, with an appropriate vacuum capacity. Now it is possible, e.g., to load and position three block-bottom bags of each 100 liters per each cycle in the vacated empty evacuating chamber, while interposing a reciprocating charging device moving preferably at right angles to the direction of motion of the filled block-bottom bags. After closing the chamber, the evacuating is carried out until the desired minimum end pressure is obtained. Thereafter inert gas or a gas mixture may be introduced to reduce the minimum end pressure and during this operation the opposite chamber is unloaded and loaded respectively. Synchronical control takes care of constant alternating yet continuous presence of a number of block-bottom bags in either evacuating chamber until the predetermined rate of vacuum has been reached. Vacuum sealing is then finally effected within the evacuating chamber and following decompression of the evacuating chamber. The set of preshaped block-bottom bags is transported off upon a second conveyor. In view to the space requirements it is also preferable to position and displace the off transport device in a reciprocating manner perpendicular to the direction of the movement of the bags. (Fig. 1)
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