Paper machine drainage foil with wear-resistant insert

Claim 1

For use in a paper machine having a traveling screen for supporting water-wet pulp during the drainage of water therefrom, an elongated drainage foil intended to extend lengthwise transversely under the full width of the screen and having a leading edge for initial contact with said screen, followed in the direction of travel of the screen by an upward-facing land surface in supporting relation thereto, followed in said direction of travel by a drainage surface diverging from the underside of the screen to control the drainage of water from said pulp, the improvement in said foil comprising, a first body defining said drainage surface and a second body defining all of said land surface from said leading edge to said drainage surface, said land surface being covered at least in part with a wear-resistant material that is permanently affixed to said second body and is harder than the material of said second body, an elongated channel running the length of the first body, said second body being removably disposed within said channel wherein said second body is an elongated slab of solid material having first and second wide sides substantially parallel to each other, and a third side joining the first side at an acute angle and joining the second side at an obtuse angle, said land surface being on said third side, said second body being installed in said first body with said first side oriented forward of said second side whereby said first and third surfaces meet at said acute angle to form the leading edge of said drainage foil, and said second and third surfaces meet at a line that coincides substantially with the forward edge of said drainage surface, said elongated channel in said first body has first and second side walls and a bottom wall and an elongated opening into the channel between the edges of said first and second side walls that are remote from said bottom wall, and first and second auxiliary slots extending in opposite directions, respectively, substantially perpendicularly into said first and second side walls, and having retainer means on said second body extending, respectively, from said first and second wide sides into said first and second auxiliary slots to retain said second body in said channel against force oriented to move said second body out of said channel through said elongated opening, and said retainer means comprises an array of discrete projections spaced in a line along each of said first and second wide sides.