Web drying station, has a heated unit within a sealed hood with an overpressure chamber and a sealing belt over the web and sieves in a recess at the heated unit periphery

摘要

Web drying station, has a heated unit within a sealed hood with an overpressure chamber and a sealing belt over the web and sieves in a recess at the heated unit periphery. The machine for the production and/or finishing of a paper or cardboard web (14) has at least one heated unit (10) especially as a press roller, drying cylinder and/or the like. Part of its circumference where the web (14) passes around it has at least one sieve (16,18) and an outer sealing belt (20). The assembly is shrouded by a hood (12) with its interior at an overpressure through a liquid or gas medium under pressure. The sealing belt (20) is wider than the paper/cardboard web (14). The sieves (16,18) project at both side edges, so that they are pressed with sealing against the surface of the heated unit (10) by the overpressure within the pressure chamber (22) of the shrouding hood (12) and/or the pressure chamber (22). The hood (12) is sealed against the ambient atmosphere by seals (24) at both end sides between an end wall (12') of the hood (12) and a radial counter wall (26), preferably in a cylinder shape. At least one cylinder counter wall (26) is in a zone at one end of the heated unit (10), formed by a disk or a shoulder at the bearing journals (30) of the heated unit (10). The end walls (12') of the hood (12) extend as far as the bearing journals (30). The web (14) and the sieves (16,18) are within a recess (28) in the peripheral surface of the heated unit (10). The sealing belt (20) is wider than the recess (28), with its edges overlapping both sides of the recess. The depth of the recess (28) is at least equal to the combined thickness of the web (14) and the sieves (16,18). At least one sealing pocket or chamber can be at the periphery of the heated unit (10) at each side of the sealing belt (20) to cover or face it, linked to the ambient atmosphere so that its internal pressure matches the ambient or atmospheric pressure. At least one end side of the heated unit (10) is of a heat resistant material. The seal (24) at the end wall (12') of the hood (12) is held in place by a spring. The overpressure zone (22) within the hood (12) is sealed by an external non-contact seal. The heated unit (10) is a substitute shoe press.