(57) In a twin wire paper forming machine an endless top wire (14) passes round a lead-in
roll (12) and meets a bottom wire (15) in the region of a lead-in-foil cover (1).
The two wires pass over a secondary foil cover (4) which presents alternately solid
and open areas to create pulsating pressure on stock between the wires, and then below
a secondary trailing cover (10) whose leading edge doctors water on the top wire into
an autoslice (9), and the top wire (14) is separated from the bottom wire (15) in
the region of a sheet transfer box (11) to pass round a drive roll (13) and return
to the lead-in roll. The leading edge of the transverse bars (41) or blades of the
secondary foil cover (4) doctor water off the bottom wire. The secondary foil cover
(4) and the secondary trailing cover (10) establish successively sharper downwardly
forwardly and upwardly forwardly convex paths for the wires which promote dewatering.
A primary trailing cover (8) and a primary autoslice (7) can additionally be disposed
above the top wire between the lead-in-foil cover (1) and the secondary foil cover
(4). The lead-in-foil cover and the secondary foil cover can form parts of a composite
adjustably mounted unitary structure.
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