Double four drinker paper-making press section - has forming roller for lower four drinker at entry with water extn. unit and further forming roller at upper four drinker

摘要

Machine has a forming roller (4) at the press section, over the lower fourdrinier (3) where the two fourdrininers (2, 3) come together, so taht they both pass partially round it. A water removal unit, esp. a water suction chamber (6), is near the forming roller (4) or close behind it, at the upper fourdrinier, followed by a forming shoe (7) with bars (12) across the direction of material travel. Further forming rollers (8) are at the upper fourdrinier. The water extn.-chamber (6) pref. has a suction lip (5) pressed tighly against the upper fourdrinier. The forming shoe (7) at the lower fourdrinier (3) is pref. part of the suction chabmer (11) for the lower fourdrinier, with bars (12) giving a convex contour surface towards the lower fourdrinier (3). The forming shoe (7) can also be part of the suction chamber (6) for the upper fourdrinier (2), with bars (12) presenting a convex contour surface to the fourdrinier. The forming roller (4), near the stock inlet, has water retaining recesses at its outer mantle surface, without connections to the roller interior, as do the forming rollers (8) at the upper fourdrinier. The recesses in the upper forming rollers can be connected to the roller interior, with a non-rotating suction chamber to extract wafer from within the roller. The upper forming roller can also have a polished mantle, impermeable to water. A water removal unit (9), with underpressure, is between the forming shoe (7) at the lower fourdrinier (3) and the further forming rollers (8) at the upper fourdriner (2), to remove water through the upper fourdinier (2). The peak of the forming roller (4) at the lower fourdinier is higher than the level of the bars (12) at the suction chamber. A water container (10), after the upper forming roller (8), traps water spun from the roller, to be led away from the press section. USE/ADVANTAGE - The press section of the papermaking machine, as structured, gives an effective water extn. from the pulp with relatively short-length suction chambers at the lower fourdrinier and with high-speed fourdriniers, without web damage. The assembly occupies little space with reduced suction air consumption.