Wood pulp

“ Unbleached wood pulp is the material used, and by prolonged boiling with soda under comparatively low pressure, the fibres receive less drastic chemical treatment than is usual in the preparation of wood pulp. Reduction to fibrous state is accomplished by the edge runner, drawing the fibres out, thus retaining the length and strength. Kraft papers are smooth, light brown in colour, strong and flexible, and are used for wrappings where these qualities are required. ”

“ The object being merely to dry the pulp, a very heavy web can be obtained, since the water leaves this pulp very freely. The wood pulp thus obtained is perfectly clean, of a soft, white spongy fibre, and a greater portion of it is mixed with a small proportion of rag pulp and worked into book and fine printing papers. Sometimes the wood pulp is used alone or mixed with white paper shavings for book paper. The fibres are rather deficient in strength, but as a material for blotting paper they are said to be unsurpassed, while the wood paper is much liked by printers. ”

“ Chemical wood pulp of the best quality makes an excellent product, and is largely used for both print and book paper; it is frequently mixed with rag pulp, making a paper that can scarcely be distinguished from that made entirely from fine rags, though it is not of the proper firmness for the best flat or writing papers. All ordinary newspapers, as well as some of the cheaper grades of book and wrapping paper, are made entirely from wood, the sulphite or soda process supplying the fiber, and ground wood being used as a filler. ”

“ The Wood-Pulp Floor.—Floors have been accused of great sins. If the timber is not thoroughly seasoned they warp; if the boards are not properly laid they creak; and the cracks are all at times filled with injurious dust and dangerous germs. Why not invent a wood-pulp floor which shall have no warps, and no cracks, and no creaks? Dry the pulp to powder to facilitate transportation, mix with a small amount of cement, to increase the resistance of the floor, and then after making it a gelatinous mass pass it between rollers. When dry, paint it to imitate oak or other wood. ”

“ Sulphite Pulp.—The process most generally adopted for the manufacture of wood pulp is the treatment of the material in brick-lined digesters with bisulphite of lime for eight to nine hours at a pressure of 80 lbs.
Mitscherlich Pulp.—This is sulphite pulp prepared by digesting the wood at a much lower temperature and for a longer period than the ordinary sulphite. The steam is not blown direct into the mass of wood, and the pressure seldom exceeds 45 or 50 lbs., the time of boiling occupying 45 to 50 hours. ”

“ There is at present a large demand for paper pulp in America, Europe, and Japan. According to authorities on the subject, the spruce wood, which forms at least two-thirds of all the woods converted into pulp, is being exhausted. ”

“ The mechanical pulp, reaching the mill in the form of thick sheets suitably packed up into bales, is first broken up again into moist pulp. Various machines are used for this, such as Wurster's kneading engine, Cornett's breaker, or some similar contrivance. An old potcher, such as is used for the breaking and washing of rags, makes a good pulp disintegrator. The broken pulp is discharged into beating engines in any suitable or convenient manner and the right proportion of chemical wood pulp added in the form of dry sheets. ”

“ Chemical Processes.—Watt and Burgess's Process.—Sinclair's Process.—Keegan's Process.—American Wood Pulp System.—Aussedat's Process.—Acid Treatment of Wood.—Pictet and Brélaz's Process.—Barre and Blondel's Process.—Poncharac's Process.—Young and Pettigrew's Process.—Fridet and Matussière's Process.
The advantages of wood fibre as a paper material have been fully recognised in the United States and in many Continental countries, but more especially in Norway, Sweden, and Germany, from whence large quantities of wood pulp are imported into this country. ”

“ Resin is of less use.
One particularly troublesome result of having to deal with wood pulp papers is that it will not hold the threads used in ordinary binding; the thread cuts right through the paper because of the shortness or brittleness of the fibres, and if a book printed on such paper has to be bound, the only safe way to do it is to frame each page in a border of sound rag paper, and then have it sewn as usual. Wood paper will not stand bending, but breaks off short if there is anything like a joint or fold in it, and the framing or mounting prevents this. ”

“ The water thus heated and forced in leaves the wood or the pulp in the most desirable condition for work and for colour. Pulp made from wood treated below the boiling point will be white; but this process is said to secure the desired manilla colour by raising the temperature to 240° or 250° for a light pulp, and as high as 280° for a dark pulp. No pressure is required from the steam above three atmospheres, but the press may give from 450 to 500 lbs. to the square inch, and practice has shown that the greater the pressure the more speedy is the operation on the wood. ”

“ Samples of more than seventy kinds of paper made from wood-pulp have proven to be satisfactory. The cost of spruce-wood-pulp has increased in recent years with the scarcity of spruce, but now news-paper stock can be kept at the same price as in former years if the paper made from other woods proves to be acceptable to the printer. The tests showed that eleven new woods could be used for manufacturing manila paper and cardboards. But these woods are mostly grown in the West while the large plants for manufacturing products from wood-pulp are in the East. ”

“ A quality of pulp intermediate between chemically produced wood cellulose and ground wood is obtained by bleaching an especially finely ground quality of pulp wood. This product is excellent as a filler for medium grades of paper, as it is opaque—fine, and of fair color. ”

“ The most valuable trees for lumber are spruce, white pine, hemlock, cedar, white birch, ash, maple and basswood; all excepting pine and hemlock and poplar in addition are ground into wood pulp for the manufacture of paper. ”

“ Trees have been found 190 feet high and ten feet in diameter. Used in cooperage, for siding, for panelling and finishing lumber in houses, car- and shipbuilding, for sideboards, panels of wagons and carriages, for aeroplanes, [82] for automobiles, also in the manufacture of furniture farm implements, machinery, for pump logs, and almost every kind of common woodenware, boxes shelving, drawers, etc., etc. Also in the manufacture of toys, culinary woodenware, and backing for veneer. It is in great demand throughout the vehicle and implement trade, and also makes a fair grade of wood pulp. ”

“ They are made in two sets, crossing each other in the centre of the stone, and serve to carry off the pulp to the sides of the stone, in addition to giving increased grinding-surface. The pressure of the blocks of wood against the stones is steadily maintained by screws worked by suitable gearing; this is necessary in order to obtain a pulp of uniform character. A stream of water is kept constantly playing on the stone; by this means, the pulp as fast as it is formed can be conveniently carried away. ”

“ While the value of pulpwood is dependent basically upon the tons of dry pulp that can be produced from a given number of dry tons of wood, the great quantity of the wood is bought and sold either on the basis of an estimated and variable volume of wood in an assumed space, or on the theoretical quantity or volume of lumber which can be cut. ”

“ The steps subsequent to cooking chemical pulps of all kinds are similar. After emptying the digesters, the soft, discolored mass of fibers is washed and bleached. The yield of cellulose fiber is close to fifty per cent of the air-dry weight of the wood. The shives and undigested particles are removed by screening, and the pulp is either run out like ground wood on wet machines, or made up into rolls, or 36sheets, on a paper-machine. The soda pulp is shipped in rolls and the sulphite in sheets, as this is the most favorable form in which to handle them at the paper-mill. ”

“ Altho the amount of wood used for paper pulp is small in comparison with the total lumber production, being about 5.4 per cent., yet this cutting of young growth keeps the forest land devastated. In 1906 nearly 9,000,000 tons of wood were used for paper pulp in the United States.
No one who is at all familiar with the situation doubts for an instant that we are rapidly using up our forest capital. In fact it is unquestionably safe to say that our present annual consumption of wood in all forms is from three to four times as great as the annual increment of our forests. ”

“ The felt, carrying on its upper surface the thin sheet of pulp, passes between two rolls, usually 16 to 20 inches in diameter, the upper being made of wood and the lower one of cast iron. The pulp adheres to the upper drum and the felt passes round the lower drum back to the box containing the mixture of pulp and water; the thin sheet is continuously wound on the upper roll until a certain thickness is reached. ”

“ Be it known that Charles Watt and Hugh Burgess did invent a new and useful improvement in the manufacture of paperpulp, from wood and other vegetable substance.
The wood or vegetable substance, from which it is intended to make the pulp, should be first reduced to fine shavings or cuttings. This may be done in any suitable machine.
The shavings or cuttings of wood, or the vegetable substances, are then to be boiled in a solution of caustic alkali, in a suitable boiler, under pressure. The strength of the alkali is dependent on the nature of the vegetable substance used and operated upon. ”

“ The next largest use of lumber is the grinding of it into pulp to be used in making paper for our books, magazines and newspapers, wrapping papers, etc. The woods used for this purpose are mostly spruce and hemlock. The great sources of supply of pulp-wood are Maine and Wisconsin, and large amounts are imported from Canada, which greatly lessens the drain on our own forests. ”

“ In this arrangement the grindstone, fixed on a shaft, is worked by a turbine, and the wood, which is used in small blocks, is pressed against the stone by means of a series of hydraulic presses. The fine pulp is afterwards made into thick sheets by means of a board-machine, the pulp, mixed with water, passing down a shoot into a vat beneath, in which is a revolving cylinder covered with wire-cloth, which in its revolution carries with it a certain quantity of pulp in a continuous sheet ”

“ Wood fiber is made from fir or white spruce in great paper mills, where the logs are first reduced to pulp, then made into an extremely tough and continuous roll of a special type of kraft paper designed for twisting. ”

“ Statistics giving comforting assurance of an abundant yield still at hand do not consider the effect upon wood industries of the substitution of timber of a few kinds only to fill a widely varying demand. The presence of hardwoods in the southern Appalachians and pine in the southern pine belt, in quantity sufficient to replace for some time the waning supply of spruce in the north woods, offers no substitute for the latter species in the manufacture of paper pulp. ”

“ Common, and best developed in the lower Ohio Valley, but occurs from New York to Texas and Missouri.
POPLAR (See also Tulip Wood)
Wood light, very soft, not strong, of fine texture, and whitish, grayish to yellowish color, usually with a satiny luster. The wood shrinks moderately (some cross-grained forms warp excessively) , but checks very little in seasoning; is easily worked, but is not durable. Used in cooperage, for building and furniture lumber, for crates and boxes (especially cracker boxes) , for woodenware, and paper pulp. ”

“ To the right are the hydraulic presses for removing moisture from the pulp. The pulp is shipped about seventy per cent moist.
Soda Pulp.—Soda pulp takes its name from the caustic soda which is used as a solvent. Rotary digesters are employed in its manufacture. The principal wood used for making soda pulp is poplar, though chestnut and aspen are 34also used. Soda pulp is soft in texture and of no great strength, but in combination with harder stocks it lends mellowness to the sheet. ”

“ These are all small mills, and in contrast to that, it is only necessary to point out that all the other mills in Canada are working to capacity.
The annual consumption of paper pulp wood in the United States is 4,300,000 cords, representing an expenditure of $36,000,000 by approximately 250 companies.
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SHOES LIKE “THE WONDERFUL ONE HORSE SHAY.”
When a man is “on his uppers” he is in a very serious condition for then his shoe soles have worn out and he has no money to buy more. ”

“ The first is typical of any dry thin-walled cells, as is usually the case in seasoned white pine and spruce, and in the early wood of hard pines, hemlock, and other species with decided contrast between the two portions of the growth ring. As a rule buckling of a tracheid begins at the bordered pits which form places of least resistance in the walls. In hardwoods such as oak, chestnut, ash, etc., buckling occurs only in the thinnest-walled elements, such as the vessels, and not in the true fibres. ”

“ Twenty-four hours should be allowed the filler to harden. One filling is sufficient for ordinary work; on fine work the above process is sometimes repeated after the first filling has hardened.
The striking contrasts in the grain of wood such as oak and chestnut, obtained by the use of colored fillers, are due to the dark filler’s remaining in the open grain but being wiped off of the close grain—the “high lights.”
On quarter-sawed oak, each flake is sometimes sanded with fine paper, No. 00, to remove the stain that the contrast may be sharper. ”