GB1274027A - Drainage foil for fourdrinier machines or similar drainage apparatus - Google Patents

Abstract

1,274,027. Drainage foils for papermaking machines. J. M. VOITH G.m.b.H. 14 July, 1969 [12 July, 1968], No. 35279/69. Heading D2A. A drainage foil comprises a wire-supporting surface 9, following the leading edge, the surface being substantially parallel to, and in uninterrupted contact with, the wire, an adjacent drainage surface 11, having an initial surface portion diverging from the plane of the undeflected wire in the direction of wire motion, followed by at least one further surface portion, either diverging from, or adjustable to diverge from the plane of the undeflected wire in the direction of wire motion at an angle which is less than the angle that the initial portion diverges. The drainage surface may be shaped as a catenary. There may be a joint in the surface, this joint preferably being situated 20-50% of the way along the foil in the direction of wire motion. There may also be a pivot between the wire-supporting surface and the drainage surface (Fig. 6, not shown). In the drawing, initial portion 3' and trailing portion 3" are joined by flexible portion 7. The disposition of the two surfaces may be changed by means of studs 13 and surfaces 14. Surfaces 14 are attached at intervals across the machine, and taper in the crossmachine direction. Each surface has a stud 13 bearing on it, the studs being carried by a rod 12 whose position across the machine may be varied by conventional screw means (Fig. 2, not shown). Springs may be incorporated between base 2 and portion 3" to hold this portion in contact with studs 13. Other means of adjusting the disposition of the trailing surface, e.g. a turnbuckle (Fig. 6, not shown) may be used. The entire foil construction may be tilted. An insert 10, or the entire leading edge, may be formed of a wear-resistant material e.g. a ceramic or tungsten carbide.