Method and apparatus in a paper machine single-wire drying group

  • US 4,905,380 A
  • Filed: 08/30/1988
  • Issued: 03/06/1990
  • Est. Priority Date: 09/02/1987
  • Status: Expired due to Term
First Claim
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1. In a multi-cylinder drying section of a paper machine, a single-wire drying group comprising the combination of:

  • a looped drying wire;

    a plurality of successively arranged drying cylinders located outside said drying wire loop having respective axes of rotation situated in a substantially common plane, said drying wire carrying a web between successive drying cylinders and passing over a covering sector of each of said drying cylinders with the web interposed between said drying wire and a heated drying surface of said drying cylinder;

    at least one deflection roll having a perforated shell with perforations thereof extending through said shell and communicating with an interior of said roll, each deflection roll located within said drying wire loop in an inter-cylinder region between a pair of successive drying cylinders, said web-carrying drying wire having an incoming run traveling from a first one of said pair of successive drying cylinders to said deflection roll whereupon said drying wire runs over a deflection sector of said deflection roll shell, said incoming run of said web-carrying drying wire and said deflection roll shell defining a first wedge-shaped space or nip at the end of said incoming run, said deflection roll shell having an open sector free of said web-carrying drying wire;

    at least one box means, each located in a respective inter-cylinder region proximate to said deflection roll, for directing a first ejecting gas flow adjacent to said incoming run of said web-carrying drying wire in a direction opposite to the direction of travel thereof for inducing a first underpressure on said incoming run and in a space including said first wedge-shaped space, and for covering said open sector of said deflection roll by at least one of a closing compartment and an underpressure compartment of said box means.

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