GB841422A - Method and apparatus for forming an aqueous suspension of pulp fibres into a web - Google Patents

Abstract

841,422. Paper-making machines. DOMINION ENGINEERING WORKS Ltd. July 17, 1956, No. 22082/56. Class 96. A narrow, high-speed, modified Fourdrinier paper-making machine has a short wire-cloth 5 the upper run C of which hangs freely as a catenary between the breast roll 6 and the couch roll 7, so that water drainage from the pulp is aided by centrifugal force, and suction boxes and table rolls are not needed. The breast roll 6 may be at the same height, or at a higher or a lower level than the couch roll 7. The roll 8 is tiltable &c. so that it can act as a guide roll to correct wander of the wire-cloth, and the roll 9 is adjustably positioned for control of the amount of slack in the catenary C. The web S may be couched vertically upward with the aid of a water shower 13, an air blast 14, and centrifugal force as the wire moves around the roll 7. Alternatively, the web may be couched at any angle, or vertically downward. The wet press may have small diameter rolls 18, 19, each backed by two larger rolls 20 and 21, and driven by a wormtype speed-increasing gear train. No press felt is used and the high speed of the small rolls 18, 19 ensures the web S leaves cleanly. The rolls 6, 7, 8, 9 are cantilever-supported to facilitate wire-changing. The flow box 11 may be trunnion-mounted and have an internal rotating paddle which whirls the pulp and delivers it under pressure. Specifications 815,363, 841,427 and 841,441 are referred to.