Dye Preparation System for Paper Industry Using PLC

The dyes are added in the stock for the purpose of coloring the paper. The dyes used are three types      Basic dyes Aciddyes Directdyes Basic dyes owe their solubility to the presence of aminogen basic radical (NH2). They have good affinity to lignin rich pulps like ground wood pulp and unbleached chemical pulp. Acid dyes own their solubility to the presence of acid radicals, phenolic hydroxyl groups and sulphonic radicals (SO3H)..  The order of addition of various chemicals in the stock generally followed is rosin, filler dye and finally alum. The blended stock 3-3.4% consistency pulp is pumped to a constant level headbox, to maintain a constant head for the fan pump, so that the final basis weight will be fairly uniform. Before the stock is fed from the head box on the wire, it is subjected to screening through a set of centre-cleaners and selectrifier screen. Selectrifier screen also serves the purpose of straightening the fibers, so that a good forming is achieved in the paper. The methyl violet is a basic dye and rod amine is an acidic dye, which is used as ancoloring agent in the paper process industry.