A pouch machine forms a series of pouches in a continuous web of pouch material by folding the web and then forming spaced side seals to define a pouch closed on three sides with an initially unsealed mouth on top. The pouch is opened to its maximum volume prior to filling by pressurizing the pouch. Pressurization is achieved by introducing a curtain of compressed air under a plate and passing the mouths of the pouches adjacent the plate and thus through the air curtain. The air curtain is preferably at least as wide as the mouth so the entire mouth is subjected to the air pressure, thereby causing the pouch to inflate to its maximum volume. Continuous web height control is provided to assure alignment of the web with the plate. A lip at the mouth may be formed by folding one edge of the pouch over prior to creation of the side seals. After filling the lip is folded back up prior to top sealing to make a balanced pouch. Alternately the lip may be formed by folding the web unevenly so the back panel is higher than the front panel. A plow with driven adjustability provides precise control of folding such that the web can be folded into either a balanced or lipped pouch.
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