Abstract: A double-walled or quadruple-walled foil bag (8) for receiving a liquid, more particularly beer, which is to be arranged in a preferably spherical pressure tank, consists of flat, superposed, circular or polygonal foil pieces (2a-2c) which are welded together at the edge. The foil pieces which form a foil bag half (8a, 8b) are provided in the central area with a connecting piece (5) which penetrates them. The foil pieces, which form the double or quadruple wall, are preferably cut out of a flattened, commercially available foil tube. In order to test the finished foil bag for imperviousness, only an annular peripheral area which runs next to the weld seam (6) and which is connected via a connecting channel with a central area surrounding the connecting piece (5) is inflated.

Abstract: PCT No. PCT/EP78/00009 Sec. 371 Date Apr. 11, 1979 Sec. 102(e) Date Apr. 04, 1979 PCT Filed Aug. 08, 1979 PCT Pub. No. WO 79/00093 PCT Pub. Date Mar. 8, 1979A pressure tank is to be filled with a carbonated beverage, in particular beer, without the beverage coming into contact with the walls of the pressure tank. To this end, there is inserted in the pressure tank a plastic bag into which the beverage is introduced. The plastic bag is replaced whenever the tank is to be refilled. The pressure tank is provided with two openings at opposite points which are closed by fittings. The plastic bag is introduced through one of the two openings. To prevent that as the beverage is introduced there remain folds at points of the plastic bag which are already covered by the beverage, it is proposed to introduce the plastic bag into the pressure tank along with a hoselike jacket which as the bag is being filled assures a gradual unfolding thereof.