Abstract: A dryer bar apparatus of a dryer for drying a web in a papermaking machine includes a number of turbulence bars circumferentially spaced equidistantly around the inner surface of the dryer shell for generating turbulence within a layer of condensate. The arrangement is such that uniformity of the transfer of thermal energy in the cross machine direction is maximized while the transfer of thermal energy through the dryer shell from the inner to the outer surface is minimized. Also, the number of turbulence bars is determined by the equation: N=int{2?Ri/[4?(Ri/d)½+W]} in which: N=the number of turbulence bars in the dryer shell; int=an integer number of a value in {} brackets; ?=3.1415; Ri=the inside radius of the inner surface of the dryer shell in inches; d=an average depth of the layer in inches; W=a width of each of the turbulence bars in inches.

Abstract: An apparatus is disclosed for increasing a transfer of thermal energy through an inner surface of a hollow cylindrical dryer of a papermaking machine to a peripheral outer surface of the dryer. The apparatus includes a plurality of bars of rectangular cross-sectional configuration, each of the bars extending axially within the dryer. The bars are disposed spaced and parallel relative to each other with each of the bars being urged outwardly against the inner surface of the dryer. A mechanism is provided for urging each of the bars radially outward against the inner surface of the dryer. The mechanism includes a plurality of hoop rings which are spaced axially within the dryer, each hoop ring being disposed normal to an axis of rotation of the dryer.

Abstract: A paper machine comprising a single tier drying section including at least two dryer groups is disclosed. In one group, the axes of rotation of at least two consecutive drying cylinders lie substantially in a plane, and the axes of rotation of the vacuum rolls are disposed below the plane of dryer cylinders. In the next group, the axes of rotation of at least two consecutive drying cylinders lie substantially in a further plane which is non-coplanar with the plane defined by the dryers of the first dryer group. The vacuum rolls of the second dryer group have their axes of rotation disposed above the further plane. The dryer transfer which transfers the web from one dryer group to the next one includes a joint run of the felts of the respective dryer sections and a vacuum roll at the downstream end of the joint run. The joint run receives the web between the felts when the web passes through the joint run.

Abstract: A vacuum roll transfer apparatus is disclosed for drying a web extending through a single tier dryer section of a paper machine. The apparatus includes a rotatable perforate shell having a first and a second end. A stationary duct is disposed within and along the length of the shell between the ends of the shell. The duct is connected to a source of partial vacuum and the shell defines a plurality of holes along the length thereof such that is use of the apparatus, when the duct is connected to the source of partial vacuum, a partial vacuum is generated within a chamber defined between the shell and the duct. A flow restricting arrangement is disposed within the duct for generating a greater vacuum level adjacent to at least one of the ends of the shell for facilitating threading of a tail of the web.