METHOD AND DEVICE FOR CONTINUOUS WREATHING OF THERMOPLASTIC, SHRINKABLE TUBULAR COVERS

摘要

A method continuously curves thermoplastic shrink tubing casings for sausages. This is achieved by heating inside a spiral path along which the casing is guided, inflated. The tubing is filled with gas under slight pressure before entering the unit. In this novel process, during heating, the casing is driven inside and outside the spiral path at different speeds, thus causing curvature. Hot air is distributed uniformly over the circumference of the casing. A predetermined temperature distribution is maintained around the casing. Also claimed is the corresponding machinery. This comprises the forming unit, preceded and followed by pinch rollers or nips (2, 15), trapping inflating gas in the intermediate section. The first nips (2) are adjustable along the feed section (A) of the casing (1). The forming unit (3) has a spiral (19) configuration along which the driven guide rollers (7, 8) are arranged, resting internally and externally against the inflated casing. Hot air from within, heats the casing.