Machine for the manufacture of a fibrous plasterboard web

Abstract

A machine for the manufacture of a fibrous web includes a back liner former, a top liner former and at least one middle layer former. The back liner former is configured for producing a back liner, comprised of a fibrous web, with one side of the back liner having a higher fines content. The top liner former is configured for producing a top liner, comprised of a fibrous web, with one side of the top liner having a higher fines content. The middle layer formers, being configured for producing at least one middle layer, comprised of a fibrous web, with one side of the middle layer having a higher fines content, the other side of the middle layer having a lower fines content. Each middle layer former and the top former having couch rolls that define an associated couching zone; wherein the back liner former and each middle layer former are configured such that the side of the higher fines content of the back liner contacts the lower fines content side of the middle layer.

What is claimed is:  
     
         1 . A machine for the manufacture of a fibrous web, comprising: 
 a back liner former configured for producing a back liner comprised of a fibrous web, the back liner having a higher fines side with a higher fines content;    a top liner former configured for producing a top liner comprised of a fibrous web, the top liner having a higher fines side with a higher fines content; and    at least one middle layer former configured for producing at least one middle layer comprised of a fibrous web, the middle layer having a higher fines side with a higher fines content, and a lower fines side with a lower fines content, each said middle layer former and said top former having a couch roll defining a couching zone associated therewith, wherein said back liner former and each said middle layer former are configured such that the higher fines side of the back liner contacts the lower fines side of the middle layer.    
     
     
         2 . The machine of  claim 1 , wherein said back liner former is a Fourdrinier former having a first machine wire web; said first machine wire web being configured to convey a fibrous web, with the higher fines side of the back liner facing away from said first machine wire web.  
     
     
         3 . The machine of  claim 1 , wherein said at least one middle layer former is a gap former having a forming roll, said gap former being configured to produce the middle layer in a manner such that the higher fines side thereof faces said forming roll.  
     
     
         4 . The machine of  claim 1 , further comprising a first headbox and a second headbox, said first headbox being associated with said middle layer former and said second headbox being associated with said back liner former wherein the jet direction of said first headbox is generally opposite the jet direction of said second headbox.  
     
     
         5 . The machine of  claim 1 , wherein said couch roll of each said middle layer former is configured to redirect the flow of the middle layer in said couching zone.  
     
     
         6 . The machine of  claim 1 , wherein said back liner former and one of said middle layer formers are configured such that the higher fines side of the back liner is couched together with the lower fines side of the middle layer.  
     
     
         7 . The machine of  claim 1 , wherein said top liner former is a Fourdrinier former having a second machine wire web, said second machine wire web being configured to produce the top liner with the higher fines side of the top liner facing away from said second machine wire web.  
     
     
         8 . The machine of  claim 1 , wherein said couch roll of said top liner former is configured to redirect the flow of the top liner in said couching zone.  
     
     
         9 . The machine of  claim 1 , wherein said machine is configured such that the higher fines side of the top liner is couched together with the higher fines side of the middle layer.  
     
     
         10 . The machine of  claim 1 , wherein at least one of said middle layer formers includes a single layer headbox.  
     
     
         11 . The machine of  claim 1 , wherein at least one of said middle layer formers includes a multi-layer headbox.  
     
     
         12 . The machine of  claim 1 , wherein at least one constant pressure drainage element is included in association with at least one of said back liner former, at least one of said at least one middle layer former and said top liner former.