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811 



irrcat variety of vegetable materials capable of 

 yielding suitable lUnv. together witli inventions 

 relating In pr.ieessos and apparatus for treating 

 those snl>--tances for their r< inversion into paper 

 stock, have so greatly enlarged the capabilities 

 of paper-makers that they can produce any de- 

 siivil amount, and in an endless variety of size, 

 weight, and strength. 



Poplar, bass, sycamore, pine, spruce, mid hem- 

 lock are i In- principal woods now used for paper 

 Moek : while oat, rye, and wheat straws, old 

 rope, jute buts. and a variety of grasses, each con- 

 iributc valuable fibre for the use of the paper- 

 niaker. The process of reducing wood to pulp 

 was invented in (ierinany. and it isonly recently 

 that it has been conducted in this country. The 

 process consists in sawing the sticks to a small 

 si/.e and then putting them, in a wet condition, 

 to a grinding machine, which takes them at 

 the end and reduces them to what would be a fine 

 powder if they were dry. The pulp is allowed to 

 run into vats, whore it becomes thoroughly 

 soaked. It is then drawn off upon broad rollers 

 covered with cloth, after the manner of a paper- 

 making machine. A small percentage of some 

 glutinous substance is added ; and the pulp, after 

 becoming of uniform thickness, is run between 

 rollers nnd the water expressed. In this shape it 

 is rolled into bundles and tied. It is bought and 

 sold wet, for the reason that it will absorb a cer- 

 tain amount of water until saturated, and then 

 will take no more. In bills of sale, about 40 per 

 cent, of the watered pulp is considered the true 

 weight. Another process, known as the sulphite, 

 yields a strong and fine fibre. Recent discoveries 

 have been made, and processes and apparatus 

 have been devised, which have greatly cheap- 

 ened the cost of converting wood into fibre for 

 paper. The latest processes, known as the " soda," 

 include large boilers or digesters, made of iron or 

 steel, capable of holding two or more cords of 

 wood, and strong enough to stand a pressure of 

 121) to 150 pounds to the square inch. In these 

 digesters the wood, straw, or other vegetable sub- 

 stances are subjected to the action of a suitable 

 chemical cooking-liquor of a given strength, 

 under pressure varying from 50 to 120 pounds 

 to the inch, according to the material. This is 

 known as the " new process," and is adapted for 

 economical use, for treating any of the woods 

 above-named and straws, grasses, old rope, and 

 other materials. But, because of some differ- 

 ences in the characteristics of each of these mate- 

 rials, the apparatus employed is modified in 

 some of its features, so as to meet the require- 

 ments necessary in securing the most economical 

 operations for saving time, labor, fuel, and chem- 

 icals in the treatment of the respective materials. 

 Some kinds of wood have as a constituent part a 

 resin or gum, which requires a higher tempera- 

 ture and strength of the chemical cooking-liquor. 

 S<> also with the different straws and grasses, the 

 nature and peculiar qualities of the substances 

 composing the lignine in them, which are to be 

 dissolved (so as to free the true fibre from the 

 matters that are worthless for making paper 

 lilire), require different degrees of temperature 

 and strength of OOoUng-uqaora, and varying 

 length of times of treatment, for the economical 

 production of the commercial fibre. Again, the 

 different substances permit the use of different 



kinds of chemicals. The usual chemicals em- 

 ployed are lime, potash, soda-ash, and can-tie 

 soda. For the reduction of wood the last-named 

 i- -> net-ally employed, while for the reduction of 

 straws and grasses lime is used b.can-e of its 

 cheapness. Cooking liquors of all these kinds of 

 alkalies have been employed in open vessels made 

 of wood, for cooking straw and grasses and old 

 rope, jute buts, etc., and, Ix-cause in such vcs.-els 

 the temperature of the liquor could not be had 

 above boiling heat, these substances were neces- 

 sarily cooked from forty-eight to sixty hours. By 

 the use of closed vessels with a pressure of two 

 or three atmospheres, the time of cooking is re- 

 duced to two or three hours ; but the liquor is 

 kept circulating so as to prevent a packing of 

 the material that is being cooked. 



There is one apparatus for the reducing of the 

 various kinds of straw ; another for cooking old 

 manilla rope ; a third for reducing straws and 

 grasses to fibre by the use of alkaline cooking- 

 liquors, by which all the Jignine will be dissolved, 

 leaving the fibre free. In this complete reduc- 

 tion of the straw and grasses, the mass of ma- 

 terial treated will be generally reduced in bulk 

 as the cooking of the material is advancing, 

 and as this reduction of the bulk of the charge 

 progresses, the operator will open the valves of the 

 three upper branch pipes at intervals, one at a 

 time, beginning with the upper one. After the 

 cooking of the material is completed, the product 

 will be blown out and subsequently treated as 

 cooking straws and grasses are generally treated. 

 This form of apparatus is admirably adapted to 

 reducing jute buts. A fourth apparatus is used 

 for reducing poplar and other woods. The wood 

 is reduced to small chips and filled into the 

 chamber of the boiler in the usual manner. The 

 chamber contains central within it a steam 

 heater composed of a series of three-inch pipes 

 running from the top to the bottom, and extend- 

 ing across the chamber from its rear side to its 

 front, so as to divide the chamber proper into 

 two equal compartments, into which the wood 

 chips will fall when introduced from the machine 

 above. The caustic soda is introduced within 

 the boiler up to about five-eighths of its vertical 

 extension, and live steam at about 120 pounds is 

 introduced into the steam heating pipes (dividing 

 the chamber of the boiler), for heating the 

 cooking-liquor while it is being circulated. By 

 means of a pump, a dual circulation of the liquor 

 will be produced, as the pump draws the liquor 

 from an annular strainer, at two-thirds of the 

 height of the boiler, and forces the liquor con- 

 tinuously in two directions. One portion of the 

 liquor, taken from the annular strainer, is forced 

 into a circular sprinkler arranged in the upper 

 end of the boiler, to escape in numerous small 

 streams that fall on the wood chips below and 

 saturate them ; while the other portion is forced 

 into the boiler at a point below its perforated 

 bottom, and is made to move upward through 

 the lower portion of the mass of wood chips. 

 This dual circulation is continued without any 

 change for about five hours for reducing poplar, 

 basswood, or other woods that are free from 

 pitch or resins ; and about eight hours for reducing 

 wood of the nature of pine, spruce, and hemlock. 

 With this dual circulation, only about two-thirds 

 of the volume of cooking-liquor heretofore re- 



