Nozzle apparatus for handling web material

Claim 1

In nozzle apparatus for handling and/or treating webs, including a nozzle box having a pair of opposed nozzle slots located at the upper regions of respective spaces defined by respective inner and outer side wall portions of the nozzle box, the improvement comprising: said nozzle box includes a carrying surface defining a pair of opposed curved guide surfaces which merge at their respective ends with a carrying surface portion situated between said pair of curved guide surfaces which curves toward the interior of the nozzle box in the shape of a continuous and smooth arc to define a recess below the uppermost points of said curved guide surfaces; and wherein each of said pair of nozzle slots has a nozzle mouth located on a respective one of said curved guide surfaces from which a gas jet issues from said nozzle slot onto said respective one of said curved guide surfaces; and wherein said nozzle slot mouths are each located such that the initial direction of the gas jets issuing therefrom forms an angle with the direction of web run which does not exceed about 70° so that the gas jets follow said curved guide surfaces of said carrying surface without separating therefrom up to said recess formed between said nozzle slots; and wherein said recess is dimensioned to act as a tranquilization zone where the gas jets flowing in opposite directions meet to form a gas cushion for supporting the web, said cushion extending over a considerable distance in the direction of travel of the web.