Press section

The press section of a machine for making a web (10) of fibrous material (especially paper or paperboard) includes a single centrally placed, cylindrical press roll (12) of large diameter. The roll operates in conjunction with at least one press shoe (14,16) having a concave face which presses a flexible, circulating press belt (18,20) against the roll to form at least one press nip (P1,P2), which is elongated in the direction (L) of web travel. At least one felt or sieve belt (26,28) passes through the press nip.Also claimed is a press section having the inverse arrangement in which a single, large-diameter circulating press belt operates in conjunction with one or more press shoes and corresponding opposing rolls. Preferably the press roll, which is of the internally supported, controlled flexure type, has a diameter which is more than 1500 mm and is more preferably around 2000 mm. The roll has a closed or smooth cylindrical surface, and supports several press shoes (14,16) placed one after the other in the direction of web travel, each forming an elongated press nip, an each having its own circulating press belt (18,20). Each press nip has a single felt, the first felt having an open surface, and the second an open or closed surface. The felts each lie preferably between the product web and surface of the respective press shoe. One press shoe lies directly below the press roll, whilst the other is so positioned that the direction of its action towards the axis of the press roll makes an acute angle with the vertical direction of the action of the first.