Abstract

The manufacture of non-returnable packages is frequently carried out by the conversion of web-shaped, laminated packing material to a tube, filling of the tube with milk, and sealing and forming the filled packing containers to the desired shape. During the forming, which is done by external forming devices, the contents are used as a mandrel or a holder-up for the forming device, so that the desired shape can be achieved without creasing or other deformations. The above-mentioned forming principle works less well if the packing containers are not completely filled, but have a certain air space or headspace. The proportioning of the contents also becomes uncertain and the desired accuracy of volume cannot always be achieved. These difficulties are overcome by the invention wherein a sealed off part of the packing material tube is pressurized with the help of gas during the forming process, so that the internal back pressure required during the forming is obtained, independently of the quantity of contents. The method also permits an accurate proportioning of the contents either by continuous feed at a controlled flow rate or by discontinuous feeding in portions. The invention also relates to an apparatus for the realization of the method.