Abstract: A doctor blade assembly has a doctor blade supported in a blade holder. The blade has a projecting front edge adapted to be placed in contact with a moving surface to be doctored, and a rear edge adapted to be received in the blade holder. The blade is preloaded in a manner such that tensile stresses are induced in the front edge thereof. The level of such tensile stresses is below the yield strength of the blade material, yet high enough to prevent compressive stresses from developing at the blade front edge as a result of heat being generated by frictional contact between the blade and the moving surface being doctored.

Abstract: A finger-type doctor blade holder has a plurality of pressure fingers spaced along the underside of a loading plate. A doctor blade is removably supported in recesses defined between the pressure fingers and the loading plate, and the pressure fingers are mounted for pivotal movement about an axis extending across the surface to be doctored. A flexible loading tube is located alongside the finger pivot axis in a tube tray, and a force transmitting member is interposed between the pressure fingers and the loading tube. The rigidity of the force transmitting member prevents upward bulging of the loading tube between the pressure fingers, and the surface of the loading tube is indented by either the force transmitting member or a separate member at the base of the tube tray. The indentation in the tube surface enables the tube to act as a rolling diaphragm when compensating for variations in the distance between the pressure fingers and the base of the tube tray.

Abstract: A creping doctor in which a long, thin blade is applied to a roll surface at an angle to the tangent at the line of contact such that the blade presents a wide surface to the product being removed from the roll. A preferred angle is approximately normal to the surface, so that the roll surface tangent and the wide blade surface receiving the product make an angle ranging between acute and obtuse. A bladeholder provides both coarse and fine compliance of the blade to roll surface contour variations. Blades incorporating resilient means distributed along the back edge for cooperating with the bladeholder are also described.

Abstract: A headbox of the pressure nozzle type has a slurry distributor providing a plurality of pairs of separated slurry passages arrayed in the cross-machine direction. The passages of each pair open at their input ends to a manifold located at one side of the distributor. Within the distributor each passage turns at a sharp angle and all the passages are aligned in the machine direction at their output ends. A nozzle structure of a turbulence-generating type is shown coupled to the distributor.