Patent ID: 8529733

Claim:
A forming section for a twin fabric papermaking machine, the forming section constructed and arranged to receive a pair of forming fabrics comprising a first fabric and a second fabric, each supported by a plurality of rolls and support elements, the forming section comprising (i) a headbox having a headbox slice, wherein in operation (a) the headbox delivers a jet of stock through the headbox slice onto the first fabric at a point of impingement; (b) the first fabric passes over a first support element upstream of the point of impingement, and carries the stock as a layer after the point of impingement; and (c) the second fabric passes over and is guided by a second support element into contact with the stock layer proximate the point of impingement and thereafter cooperates with the first fabric to sandwich the stock layer; and (ii) a plurality of drainage shoes, comprising at least (a) a first drainage shoe located to support a selected one of the first and second fabrics in sliding contact; (b) at least a second drainage shoe downstream of and spaced apart from the first drainage shoe over which a selected one of the forming fabrics passes in sliding contact, wherein (1) each drainage shoe is constructed and arranged to provide continuous contact and support in the machine direction to the respective selected one of the forming fabrics, and has (A) a leading edge and a trailing edge; (B) a fabric contacting surface extending to the trailing edge and having predetermined machine direction and cross-machine direction profiles and being constructed and arranged to deflect both the first and the second fabrics and the stock therebetween by a selected angle of wrap of between 5° and 50° comprising an angular displacement between the leading edge and the trailing edge of the drainage shoe, said angular displacement being measured by a change in orientation of a line tangent to the fabric contacting surface at the leading edge in relation to a line tangent to the fabric contacting surface at the trailing edge, such that a total of the selected angles of wrap for all of the drainage shoes together is between 10° and 100°; and (C) a machine side surface; (2) at least one of the drainage shoes is secured to a drainage box and is provided with a plurality of drainage openings which extend from the fabric contacting surface through to the machine side surface of the shoe; and (3) at least one of the drainage shoes is secured to an adjustable drainage box constructed and arranged to be selectively securably adjusted by at least one of translation and pivoting.