Abstract: A headbox having a tube bank composed of a multiplicity of tubes arranged in machine direction rows of superpositioned tubes. The tubes extend from an unitary outlet wall of the headbox and are supplied by a single header or manifold. The tubes extend to the inlet of a single nozzle which is formed with an upper planar wall which converges toward a lower planar wall. The converging walls of the nozzle define two radially extending planes which converge at an imaginary centerline which extends in the cross-machine direction. The individual rows of tubes each lie along a radial plane which extends through the centerline. The radial planes defined by each tube row will preferably be evenly spaced in angle between the nozzle walls. The injection ends of the tubes lie on a defined cylindrical surface extending between the nozzle walls and extending the width of the headbox in the cross machine direction.

Abstract: A headbox is provided which provides an improved uniformity in the velocity profile of the stock solution across the slice opening. As a result, improved fiber alignment is provided across the width of the entire slice opening and mis-alignment of the fibers towards the outer edges of the slice opening is avoided. The headbox includes an improved nozzle design with pondsides that are not parallel to one another but which are angled inwardly as they extend from the tube bank to the slice opening. Further, several columns of outer tubes of the tube bank may also be angled inwardly as they extend from the header to the nozzle section. The center tubes would be disposed in a parallel relationship to one another. A sealing arrangement is provided between the roof of the nozzle section and the pondside which permits the incorporation of a double knuckle for extending and retracting the roof to adjust the L/b ratio.

Abstract: A headbox has a tube bank of tubes arranged in machine direction rows. The tubes extend from an outlet wall of a header to the inlet of a nozzle. The upper and lower walls of the nozzle converge toward the nozzle outlet, and planes extending from the walls (nozzle roof and apron) converge to define an imaginary centerline extending in the cross-machine direction. The rows of tubes lie along radially extending planes defined with respect to the centerline. The injection ends of the tubes define a cylindrical surface extending between the nozzle walls. Stock from each tube is directed radially toward the centerline along flow paths of equal length. Trailing vanes may be positioned between the rows of tubes so that each flow experiences almost identical flow boundary conditions as it moves towards the nozzle outlet, hence contributing to more uniform fiber orientation in the resultant paper web.

Abstract: A coater head has a housing which defines a coating pond supplied with coating under pressure. A plurality of bars extend within the coating pond in the cross-machine direction, and are spaced parallel to one another in the machine direction. A paper web is engaged against a backing roll, and travels through the coating pond past a metering blade which applies coating from the pond to the web. The bars induce a turbulent flow which shears bubbles of air entrained in the coating pond, thereby reducing the bubble diameters and air-induced imperfections in the coating. Greater machine speed, which tends to entrain more air, induces greater shear at the bars which causes bubble size to be more greatly reduced.