Patent ID: 6045658
Filing Date: 2000-04-04
Classification: D21F

Abstract:
An extended nip press apparatus for pressing a web of paper, said apparatus comprising:a press shoe defining a concave surface;a backing roll cooperating with said concave surface for defining therebetween an extended nip pressing section;a looped bearing blanket slidably cooperating with said concave surface, said blanket being disposed between said press shoe and said backing roll for supporting and guiding the web through said pressing section;electromagnetic means drivingly cooperating with said shoe, the arrangement being such that when said electromagnetic means is energized, said shoe is electromagnetically urged towards said backing roll for pressing the web;said electromagnetic means including:a plurality of electromagnetic units disposed in a cross-machine direction so that each unit when energized exerts a force on said shoe for urging said shoe towards said backing roll, wherein each electromagnetic unit includes a ferrite bar devoid of any coil recesses and having a bearing surface of a first dimension in the cross-machine direction, the ferrite bar bearing surfaces of adjacent electromagnetic units are spaced apart by a second dimension in the cross-machine direction, which is larger than the first dimension, and each said ferrite bar is rigidly secured to said press shoe;an electromagnetic coil wound around said ferrite bar so that when said coil is energized, said ferrite bar and shoe secured thereto are urged towards said backing roll; andcontrol means for controlling the force exerted by each unit.