HYBRID TYPE FORMING SECTION FOR A PAPER MAKING MACHINE

摘要

A twin fabric hybrid forming section (1) for paper making machine is described in which: the pitch of the fabric support elements (70), (71), (73), (72) decreases progressively in the machine direction; the level of vacuum applied to the forming fabrics (2), (4) through the dewatering boxes (53), (54), (10) AND (55) increases in the machine direction; the two forming fabrics (2), (4) together with the stock sandwiched between them traverse at least four separate and distinct vacuum zones within the forming section as they proceed in the machine direction; the level of vacuum applied to the last of the at least four separate and distinct vacuum zones is higher than the level of vacuum applied to the first of the separate and distinct vacuum zones; the level of vacuum applied to the at least four separate and distinct vacuum zones follows a preselected profile; and the dewatering boxes (53), (54), (10) AND (55) carrying the fabric support elements (70), (71), (73), (72) are arranged so that the fabric support elements (70), (71), (73), (72) are located in an alternating sequence on the machine sides of both of the forming fabrics (2), (4).