Press arrangement on a paper or paperboard machine

摘要

In a press arrangement on a paper or paperboard machine for processing a web (52) of fibrous material in a press nip (10,P1) formed between a press jacket (14) running over a press shoe (12) and an opposing surface (16), the press shoe is supported on a non-rotating beam (18). A surface (20) of the shoe facing the support beam and/or the corresponding surface (22) of the support beam is or are each convexly bowed with respect to the other. Preferably in one arrangement, the supported face (20) of the press shoe (12) is bowed in such a way that, under the normal working load of the press, there is contact between it and the surface of the support beam (18) over substantially the entire width of the machine. At the same time, the form of the press shoe is such that, in the unloaded state, the upper (i.e. web-pressing) face (24) of the shoe (12) is substantially flat. The press shoe has a maximum thickness at the centre of the machine (in the cross-machine direction), and may be supported on a spring-loaded devices (36,38) near its edges. In other embodiments, the lower face of the shoe may be flat whilst that of the support member is bowed, and the surface of the opposing roll (34) may be bowed also.