PAPER MACHINES.
This machines are used to manufacture paper-normally on the lower basis weight categories.
The basis weight ranges from 22 gsm up to 100 gsm and this types of paper are cigarette paper, security paper ( paper money, cheques, etc.), printing & writing grades, newsprint and base paper for specialty grades such as : Glassine, greaseproof, carbonless copy paper, etc.
Modern Paper machines run at various speed say up to 1500 meters per minute depending on the grade of paper being produced.The smaller the basis weight or the thinner it is, the faster it goes.
Paper machines consist of two parts, they are-Wet Part and Drying Part.The wet part is the forming
section and the Drying part is the final stage. The forming section consists of the Fourdrinier where the first equipment which is the headbox receives pulp stock from the Approach flow system. This pulp stock is distributed to the the fourdrinier wire for initial formation and drainage where foils and vacuum is applied.
More drainage is applied when the paper web goes out of the fourdrinier couch roll and is fed to the Press section where at least 46% of the moisture in the paper web remains.The paper web then goes into the drying part where it is carried forward in between canvass felts and drying cylinders which are heated with steam. The dries paper web at around 7% moisture is being flattened for even caliper thickness thru the alender stack and then finally rolled into jumbo roll of 1.5 meters diameter at the Pope Reel.
Next posting will be on Specialty &Tissue paper machines.
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