Device for controlled heating of surfaces - of continuously fed paper or cardboard sheet

摘要

Lengths of sheet material are fed continuously through heating elements in such a way that one surface, or both, may come into contact with the heating elements as required. Alternatively, neither surface may come into contact with the elements. Used with sheets of paper or cardboard, fed continuously for subsequent making up into a 'corrugated' or ribbed product. Arrangement allows either surface to be heated successively, which change over has previously been difficult and inconvenient. It also allows the withdrawal of all direct contact with the heating source.