Supporting beam for a foil in a paper machine

In an assembly including a paper machine foil having a forward leading edge and a rearward trailing edge, a supporting beam for said paper machine foil, and over which foil a paper machine wire passes in a direction from said forward leading edge of said foil towards said rearward trailing edge thereof, said beam being constituted by a box-type beam extending in a substantially horizontal cross-machine direction during operation and having a height H in the range of about 1.3 to 2.5 times the breadth L of said beam, said beam having forward and rearward side walls, the improvement comprising the combination wherein:

• said forward and rearward side walls of said supporting beam are situated in planes which are substantially perpendicular to the direction of wire run over said foil;
• said foil is situated in a region situated substantially vertically above said forward side wall of said supporting beam;
• and
• with reference to forward and rearward upper quadrants and forward and rearward lower quadrants of the interior of said box-type beam, first and second stiffener means extending substantially parallel to the longitudinal axis of said beam for inclining the principal axes of inertia of said beam at a small positive angle to the vertical and horizontal planes passing through the center of gravity of said beam relative to the direction of the run of the paper machine wire passing over said foil, said first stiffener means being disposed in said rearward upper quadrant of the beam interior and said second stiffener means being disposed in said forward lower quadrant of the beam interior, whereby vibrations of said beam caused by friction forces between said foil and the wire passing thereover are reduced.