Variable hydraulic pulse drainage cylinder former

Abstract

A cylinder former having a variable hydraulic pulse whilst drainage, for use in papermaking comprising a drainage means comprising a cylinder mould and a contoured member adjacent the cylinder mould having a plurality of hills and valleys which force entrained liquid through the fiber suspension forming on the cylinder mould so as to improve sheet formation. A baffle is provided in the discharge portion of the former to prevent stock build-up therein.

What is claimed is:  
     
         1 . A cylinder former having a variable hydraulic pulse whilst drainage, for use in papermaking comprising: 
 a drainage means comprising a cylinder mould; and    a contoured member adjacent the cylinder mould having a plurality of hills and valleys which force entrained liquid through a fiber suspension forming on the cylinder mould so as to improve sheet formation.    
     
     
         2 . A cylinder former according to  claim 1  further comprising a baffle and a seal to prevent the water drained through the cylinder mould from entering the forming zone.  
     
     
         3 . A cylinder former according to  claim 1  wherein the contoured member comprises a hinged side and a sliding side to provide control over the ratio between fiber suspension velocity and the cylinder mould velocity.  
     
     
         4 . A cylinder former according to  claim 2  wherein the contoured member is adjustable.  
     
     
         5 . A cylinder former according to  claim 1  wherein the contoured member includes a flat or curved section from which a formed sheet exits.  
     
     
         6 . A cylinder former according to  claim 1  further comprising a mixing roll adjacent a stock inlet to the cylinder mould for mixing stock to disperse fibers therein.  
     
     
         7 . A cylinder former according to  claim 1  further comprising a felt positioned above the cylinder mould to receive a sheet formed from the fiber suspension.  
     
     
         8 . A cylinder former according to  claim 1  further comprising a discharge portion for discharging excess drained water from the cylinder mould, a baffle position in said discharge portion adjacent said cylinder mould wherein rotation of the cylinder mould causes drained water to flow around the baffle providing a scouring effect.  
     
     
         9 . A cylinder former having a variable hydraulic pulse whilst drainage, for use in papermaking comprising: 
 a drainage means comprising a cylinder mould;    a contoured member adjacent the cylinder mould having a plurality of hills and valleys which force entrained liquid through a fiber suspension forming on the cylinder mould so as to improve sheet formation;    a forming wire for recovering a formed sheet from the cylinder mould;    at least one vacuum flat box;    a pick up roll; and    a transfer felt wherein water remaining in said sheet is further drained by way of the vacuum box to reach a desired dryness and the sheet is fed through the pick up roll where the transfer felt removes the sheet for further processing.    
     
     
         10 . A cylinder former according to  claim 9  further comprising a baffle and a seal to prevent the water drained through the cylinder mould from entering the forming zone.  
     
     
         11 . A cylinder former according to  claim 9  wherein the contoured member comprises a hinged side and a sliding side to provide control over the ratio between fiber suspension velocity and the cylinder mould velocity.  
     
     
         12 . A cylinder former according to  claim 10  wherein the contoured member is adjustable.  
     
     
         13 . A cylinder former according to  claim 12  wherein the contoured member includes a flat or curved section from which a formed sheet exits.  
     
     
         14 . A cylinder former according to  claim 9  further comprising a felt positioned above the cylinder mould to receive a sheet formed from the fiber suspension.  
     
     
         15 . A cylinder former according to  claim 8  further comprising a discharge portion for discharging excess drained water from the cylinder mould, a baffle position in said discharge porton adjacent said cylinder mould wherein rotation of the cylinder mould causes drained water to flow around the baffle providing a scouring effect.  
     
     
         16 . A method for forming a sheet of paper comprising: 
 a) feeding paper stock on a cylinder mould;    b) draining water through the cylinder mould from the paper stock to form a fiber suspension on the cylinder mould;    c) passing the fiber suspension to a forming zone comprising an adjustable contoured member having a plurality of hills and valleys which force entrained liquid through the fiber suspension, said contoured member being adjacent to the cylinder former; and    d) draining water from the contoured member to form a sheet of paper.    
     
     
         17 . A cylinder former according to  claim 16  further comprising a discharge portion for discharging excess drained water from the cylinder mould, a baffle position in said discharge portion adjacent said cylinder mould wherein rotation of the cylinder mould causes drained water to flow around the baffle providing a scouring effect.  
     
     
         18 . A method for forming a sheet of paper comprising: 
 a) feeding paper stock on a cylinder mould;    b) draining water through the cylinder mould from the paper stock to form a fiber suspension on the cylinder mould;    c) passing the fiber suspension to a forming zone comprising an adjustable contoured member having a plurality of hills and valleys which force entrained liquid through the fiber suspension, said contoured member being adjacent to the cylinder former;    d) draining water from the contoured member to form a sheet of paper;    e) recovering the sheet of paper from the cylinder mould by means of a forming wire;    f) draining water from said sheet by means of at least one vacuum box to reach a desired dryness; and    g) feeding the sheet through a pick up roll where a transfer felt removes the sheet for further processing.    
     
     
         19 . A cylinder former according to  claim 18  further comprising a discharge portion for discharging excess drained water from the cylinder mould, a baffle position in said discharge porton adjacent said cylinder mould wherein rotation of the cylinder mould causes drained water to flow around the baffle providing a scouring effect.  
     
     
         20 . A cylinder former for use in papermaking comprising a rotating cylinder mould for drainage; a discharge portion for discharging drained water from the cylinder mould, a baffle position in said discharge portion adjacent said cylinder mould wherein rotation of the cylinder mould causes drained water to flow around the baffle providing a scouring effect.  
     
     
         21 . A cylinder former in accordance with claim  20  wherein said baffle is curved and substantially coextensive with the cylinder mould in the CD direction.