TWIN-WIRE WEB FORMING SYSTEM WITH DEWATERING BY CENTRIFUGAL FORCES

• US 3,726,758 A
• Filed: 07/08/1971
• Issued: 04/10/1973
• Est. Priority Date: 07/08/1971
• Status: Expired due to Term

• Current Assignee: Beloit Corp. (Mitsui & Company Limited)
• Original Assignee: Beloit Corp. (Mitsui & Company Limited)
• Time in Patent Office: 642 Days
• US Class Current: 162/299
• CPC Class Codes: D21F 9/003 of the twin-wire type

Abstract

A twin-wire web making system for use in forming multi-ply or single-ply webs wherein a web stock is discharged into a nip between opposed forming wire runs arranged to converge with one another over guide elements. In one embodiment a plurality of individual forming sequences are associated with a main forming wire for receiving successive plies and merging the same together at each sequence. In another embodiment a single forming sequence is associated with a pick-up felt for removal of the ply from the forming sequence. At each sequence a head box means discharges web stock between twin wires supported by spaced breast rolls defining the nip therebetween and the wires gradually converge into general parallelism over curved guides by wrapping a portion of their surfaces so as to centrifugally dewater the stock sandwiched between the wires. In one aspect of the invention, a stationary curved surface and a rotary cylinder are positioned on the same side of the wires to guide the wires into general parallelism. The stationary surface and the roll combine to define a bi-radii path of wire travel having a first radius of curvature larger than the second radius of curvature. The stationary surface is water impermeable or permeable and includes surfaces having a decreasing radius of curvature in the direction of wire travel. The rotary cylinder includes solid rolls, open rolls and suction rolls. The head box means includes structures containing a plurality of flexible trailing elements therein defining therebetween channels converging in the direction of the nip for producing a stream having a relatively low degree of turbulence and a relatively high degree of dispersion.

Claims