. The manufacture of pulp and paper : a textbook of modern pulp and paper mill practice. od fibers that go to make up the pulp-wood structure. This must be done in a machine that willoperate continuously and at a minimum cost of production. Itis desired to make the maximum amount of pulp from each cordof wood ground, and the mixture of fibers after screening mustbe suitable for commercial use. The accompanying diagramFig. 1, shows the operations carried on in the groundwood pulpmill and their relation to one another. Screening and subsequentoperations are discussed in the Section on Treatment
. The manufacture of pulp and paper : a textbook of modern pulp and paper mill practice. od fibers that go to make up the pulp-wood structure. This must be done in a machine that willoperate continuously and at a minimum cost of production. Itis desired to make the maximum amount of pulp from each cordof wood ground, and the mixture of fibers after screening mustbe suitable for commercial use. The accompanying diagramFig. 1, shows the operations carried on in the groundwood pulpmill and their relation to one another. Screening and subsequentoperations are discussed in the Section on Treatment of Pulp. Although the principles on which the process is based are sim-ple, there is a wide variation in the details of their application,according to the policy of individual mill managements as to thequality and quantity desired and the degree of control of condi-tions obtainable. In a large majority of cases, accurate data,concerning the grinding conditions and quality of wood used arenot taken; consequently, much of the work is carried out by ruleof thumb, on a qualitative Fig 4. Fig. 2 shows in a simple way the principles involved in thegrinding process. Here 1 represents a gritty sandstone, mountedon a heavy steel shaft 2 and revolved by a source of power at wood 4 to be pulped is placed on the surface of the stone, withits length parallel to the width of the stone, and pressed upon thesurface of the grindstone by a suitable source of pressure 5. Inthis way, the power supplied at 3 is absorbed in mechanical fric- 4 MANUFACTURE OF MECHANICAL PULP §3 tion between the surface of the revolving stone and the surfaceof the stationary sticks of pulpwood, from which the fibers arebeing separated. Water is added to the pulp in the pit 6 beneaththe grindstone, bjr means of shower pipe 7, which sprays upon theface of the grindstone. The heat generated in friction is absorbedby this water, which also washes the fibers from the surface of thestone. 5. The early types of
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpaperma, bookyear1921
