Longer sausage wrapper skin manufacture involves connection of overlapped ends of skin sections on an elastically deformable expander

摘要

Natural or plastic skins(39,38) are pushed onto a mandrel one after the other so that the area(40) of their overlapping ends is located on an elastically deformable expander. The initial diameter(d1) of the expander is increased to a final diameter(d2) before or during welding together of the overlapping skin ends, thus increasing the diameter of the overlapping skin area. After welding the expander diameter is reduced to its original size. An Independent claim is also included for the process equipment which comprises a ring-shaped mandrel surrounded by a deformable elastic expander of variable diameter. Preferred Features: During welding the overlapping area is surrounded by two clamps(15) which move together to form a ring around the skin ends. The inner face of the clamps apply pressure and heat onto the overlapping skin area and form a diameter identical to the final diameter of the of the welded skin ends. Introduction of compressed air, clamping plate movement and air release is co-ordinated by a control unit. Inner faces of the annular clamp are heated to 100-200 deg C during welding. Diameter increase of the expander is effected by introducing compressed air or water inside the expander. The expander can be a closed tubular ring into which compressed air or water is introduced to effect expansion. Alternatively the ring encircles the mandrel and has pressure tight edges sitting on the mandrel allowing air or water to be introduced between ring and mandrel. Pressure exerted on the expander during welding is 2-6bar and the welding period is 3-20sec. The initial and final diameters, welding time, inner face temperature and air pressure are set at levels which ensure that after welding the diameter of the overlapping area in an unloaded state deviates by /}5% from the diameter of skin wrapper sections in unloaded state.