Page:The New International Encyclopædia 1st ed. v. 15.djvu/362

PAPER. is to dump it into a "stufif chest,' a large circular receptacle, with a horizontal agitator to keep it from settling, and then to pump it through a so-called "Jordan' or refining engine into a sec- ond stuff chest, whence it is pumped to the Four- drinier machine.

The .Jordan Exgixe is a most successful American invention, in universal use in the paper mills of America, but practicallv unknown in Europe, in spite of its large saving of time, space, and power. It was invented in 1862 by Joseph .Jordan of Paterson, X. J., who never benefited financially from the invention, and is now supported in poverty by the paper-makers of America. The '.Jordan' consists of a sta- tionary hollow cone mounted with knives on the inside which fits over a solid rapidly re- volving cone mounted with similar knives on the outside. The pulp passes between these cones, and the knives can be brought close together or separated with great accuracy, so that the degree of fineness of the pulp can be adjusted.

TuE FouEDEixiER MACHINE Consists of the following parts: A. The screens; B, the wire, with dandy roll, deckel straps, and suction bo.xes: C, the couch rolls; D, the first press; E, the sec- ond press; F. the driers; G, the calenders; H, the reel : and I, the slitter.

A. The Screens. — From the second stuff chest the pulp, which is now diluted with a large amount of water, flows through sand settlers and regulating gates to the screens. These con- sist of brass plates with a large number of longitudinal V-shaped slits cut in them, the opening being very small, only a few thou- sandths of an inch. A continuous jarring is given to these plates, which forces the fine pulp through the slits, but the lumps and impurities are retained. In some forms of screen a vacuum pump is used combined with an oscillating mo- tion of the screens, which keeps the pulp flow- ing back and forth, preventing the clogging of the slits.

wire receives a lateral motion, which greatlv assists in the felting of the fibres into a strong sheet. The forward motion of the wire tends to arrange the fibres in the same direction, and the side shake is necessary to offset this tendency, giving strength in both directions. Notwith- standing, it is easy to tell by tearing which way a sheet of paper was made on the machine. The water drains rapidly away froni the pulp, assisted by two or three 'suction boxes' under the wire, which are connected with an air pump and exhaust the water much faster than would otherwise be possible. At this point, between the first and second suction bo.xes, is situated the 'dandy roll,' a light cylinder covered with wire, which rests on the upper surface of the moist paper, giving it the impression of whatever design is on it. 'Wove' pai>er has both sides impressed with the fine woven wire; that is, the dandy roll is covered with the same wire as the paper is formed on. In laid paper, on the other hand, the dandy is covered with parallel wires, with a cross wire at intervals. Water marks are impressed in the paper by affixing the re- quired design on the dandy roll. A false water mark is sometimes made after the paper is partly dried by passing between rolls engraved with a design.

C. Couch Kolls. — At the end of the wire (that is, where it turns down over a roll to return to the starting point) are the 'couch' rolls, covered with felt, through which the wire passes bc-aring the web of paper. These rolls press the water out still more, and consolidate the fibre, giving it strength to cross alone the gap between the wire and the felt of the first press roll. These rolls correspond in function to the pressure ap- plied to the 'post' of alternate sheets of damp paper and felts in hand-made paper. D and E. The Press Rolls. — An endless woolen blanket (the 'felt') supports the tender web of paper through a pair of highly polishcil brass rolls under considerable pressure, giving the upper side of the sheet a smooth surface, and

Fig. 2. FOCBDEI.VIEE MAOHIN'E IN SECTION. B. The Wire. — The strained and purified pulp flows over an apron onto an endless traveling wire cloth, the mesh of which is 00 to 90 threads to an inch. The wire is supjiorted perfectly level on a great many small rollers (the 'table rolls'), under which "is a shallow wooden box, the 'save-all,' into which much of the water runs, leaving the pulp on the wire. The water in the 'save-all' contams much pulp and is used over again. The boundary of the flow of pulp on the sides is made by endless rubber bands, called deckel straps, which travel with the wire. These are adjustable so that varying widths of paper may be made. The frame supporting the leaving the impress of the felt on the under side. From the first press, D. the sheet runs under the second pair of rolls, E, and back through them in the rererse direction, thus smoothing the other side of the sheet and giving as even-sided results as possible.

F. The Driers. — The paper is now formed and it only remains to dry it. The driers are a series of" steam-heated metal cylinders, two to four feet in diameter, arranged in one. two. or three tiers. The paper is carried nearly round each in turn, and on to the next, being held to the hot surfaces by an endless blanket, usually of cotton. Sometimes there are smoothing rolls