GB1120211A - Improvements in or relating to headboxes - Google Patents

Abstract

1,120,211. Headboxes of paper machines. BLACK CLAWSON CO. 22 June, 1965 [23 July, 1964], No. 26449/65. Addition to 1119561. Heading D2A. [Also in Division F2] The headbox of the parent Specification is modified in that the passageways are substantially parallel and closely set over their whole length, or the connection between the slice assembly and the passageways is adjustable, to vary the spacing between the inlet ends of the passageways and the discharge outlet of the slice assembly, or both. As shown, 10 and 11 are the breast roll and wire of a Fourdrinier machine. The headbox comprises a supply chamber 13, a tube assembly 14 defining a multiplicity of small parallel pasageways and a slice lip assembly 15. The bottom wall of the chamber 13 and end of the tube assembly 14 are curved about an axis on which is mounted the rotor 30. Stock is supplied from a cross-flow header 32 and its level kept constant by control unit 35. Air under pressure is supplied through connection 36. The tubes 14 are brazed or otherwise secured together in a rectangular housing. The slice assembly has a tubular housing 60 which can telescope with the tube assembly 14. The rotor 30 has a perforated shell and axial bars welded or otherwise secured to its surface. In modifications (not shown); the tube assembly comprises corrugated sheets secured together to provide a honeycomb arrangement of passages (Fig. 5); the rotor comprises rods carried on disk members (Fig. 8), or spiders carrying at their tips aerofoil bars (Fig. 9), or a roll shell having its surface pierced to form rectangular perforations defined by tabs bent in opposite directions (Figs. 10, 11); a headbox that can be used as a secondary headbox has the tube-assembly inlet at the bottom of the supply chamber, and the tube assembly has a generally vertical upper portion and an inclined lower portion leading to the slice (Fig. 12); a headbox for a machine in which paper is formed between two vertically travelling wires has a tube assembly extending vertically downwards from the bottom of the supply chamber (Fig. 13); and the surface of the supply chamber has axial grooves and lands co-operating with the rotor to deflocculate the stock (Fig. 14).