Paper making is a long and tedious process which begins with collecting wood by cutting trees. Soft wood and hard wood are collected for this purpose. The bark is scrapped of from the surface of the wood. This wood is then chopped up and cut into small chippings. These are then separated into batches. These wood chippings are then put into water and chemicals and heated for several hours. This forms a pulp. The pulp consists of cellulose fibers, lignin and other residues. The residues and lignin are washed off to get the cellulose fibers. The pulping machines are used to form the pulp. Paper pulp can also be produced from paper itself. This is done by crushing the paper, using chemicals and de-inking the material.
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A paper pulping equipment is used for crushing virgin pulps, processing waste paper, machine broke, deinking and purifying the pulp. It mechanically disintegrates the fibers. Waste paper may contain a lot of undesirable materials like dust, sand, wire stapler pins, plastics, un-dissolved coating, plastic tapes etc. If these materials also come into the wire section of the pulper, it damages the machine and will lead to manufacture of poor quality paper. It may also lead to blockages and this will in turn lead to breaks in paper webs, performance of the dryer etc.
Pulpers operate in two modes, in continuous mode or batch wise. When it operates batch wise many factors can be controlled like the size, filler, color etc. by adding specific chemicals in certain amounts in the pulper. For deinking, substances called surfactants are used. Some other chemicals called dispersants are used to prevent the ink from depositing on the fibre. Anti-foaming agents are used to reduce the amount of foam formed. Chemicals like borax, caustic soda etc. are used to improve the effects of surfactants on the materials.
The main type of pulpers are Hydrapiler, Drum Hydrapulper, Broke pulper. Based on power consumption, they can be classified as low, medium and high power pulpers. They can also be classified based on consistency as low and high consistency.
The broke pulper includes the dry end and wet end pulper. The hydrapulper is a balanced pulper. The types of hydra pulper are D-type, Horizontal, Vertical and Drum. Old corrugated boxes, carton etc. are converted into pulp after removing the impurities using the D-type pulper. To maintain the physical properties of the fibers, the drum pulper is used. Crushing waste paper, deinking etc. is done using the drum pulper. This should be used batch wise.