US151991A - Improvement in disintegrating fibrous substances for paper-pulp - Google Patents

Description

A. s. L YMAN. Y I s for Paper Pulp..

Dis integrating Fibrous Substance Patented-Junel6,1874.

UNITED STATES PATENT @rrron AZEL STORES LYMAN, OF NEW YORK, ASSIGNOR TO ADDISON H. LAFLIN, OF HERKIMER, NEWV YORK.

IMPROVEMENT IN DISINTEGRATING FIBROUS SUBSTANCES FOR PAPER-PULP Specification forming part of Letters Patent No. 1 51,991, dated June 16, 1874; application filed April 16, 1574. i

To all whom it may concern:

Be it known that I, AZEL SToRns LYMAN, of the city, county, and State of New York, have invented a new and useful Improvement in the Art of Disintegrating Fibrous Sub stances, of which the following is a specification:

, This invention relates to the disintegration of wood, straw, hemp, flax, cotton, wool, and other fibrous substances in the manufacture of paper and for other purposes; and its main object is. to secure uniformity in the fiber produced, and at the same time preserve its strength and elasticity, a secondary object being economy of power, conjoined withrapidity of operation and a consequent diminution in the cost of production. The invention consists, in general terms, in immersing or mingling the stock, whether rags, straw, wood, or other fibrous substance, with water or any other suitableliqnid, and subjectingit to the action of rapidly-moving pickers or strikers in such a way that the requisite resistance to the blows of the pickers is furnished by the inertia of the material itself, and of the medium in which it is carried. In the rag-engine, as ordinarily constructed for beating out paper-stock, some stationary structure, generally denominated a bed-plate, is opposed to the beating roll or cylinder, underneath the same, in such a way that the stock is caught between the knives or ribs of the bed-plate and the fly-bars or knives of the roll in the revolution of the latter. In such machines the metallic ribs of the bed-plate furnish the resistance, by means of which the knives of the roll are enabled to cut and abrade the stock, and thus gradually reduce it to fiber.

But for this resistance afforded by the bedplate, or some equivalent resisting surface, it would be impossible for the beating-roll of the ordinary rag-engine to do efiective work. As its knives are constructed with a continuous edge they are not adapted for penetrating the interstices of the stock; and further, being arranged upon the periphery of the roll, muchafter the manner of the blades upon the periphery of a paddle-wheel, the great resistancethey necessarily encounter in passing through the water absolutely prevents such rapidity of movement as would be required to reduce the stock, if at the moment of impact it had no other support than that of the liquid medium in which it was floating. The action, moreover, of the ordinary engine, in which the material is caught between theribs of the bed-plate and the knives of the roll, is to crush and bruise, and to break and cut the fibers, and thus materially. impair their strength. A similar result, although'perhaps increased in degree, attends the use of all those processes for the production of paperpulp, in which the raw material is subjected to the action of grinding surfaces, whether such surfaces are smooth or corrugated or otherwise roughened. By all such processes, also, the fibers will be crushed or bruised and broken, so as to take from their natural strength.

By the improved process, now for the first time discovered, it is proposed that at the moment when the blows of the pickers are de livered upon the stock to be reduced, the stock shall have no other support than the liquid in which it is held in suspension; and as thus the only resistance that is afforded to the blows of the pickers will be the inertia of the stock itself and of the unstable liquid in which it is immersed, it is found advisable so to form the pickers that they will strike into or penetrate the stock as well as strike upon or against it, and absolutely essential so to construct and arrange them that they can bea run with a high velocity. To this end it ispreferred to use for pickers or strikers a series of points or of teeth, both because of the efficiency with which points and teeth can be made to attack the stock to be reduced, and because of the ease with which they can be driven through the water. Again, in order to secure the requisite velocity for effective work, it will be found advisable so to locate the pickers that they will act upon the stock at or near the surface of the liquid in which it is moving, since thus the pickers will merelydipinto the water without being submerged. The larger the proportion of the picker-mechanism that is exposed above the water, the lighter and consequently the faster'it can be run.

A fiber -'reducing engine embodying the principle of this improved process is not necessarily limited to any particular form or dimensions; these will be determined mainly by the character and amount of work to be performed. Various devices also may be employed for producing the requisite circulation of the material to be acted upon, and the pickers or strikers may be variously constructed, care only being had that they be made to move with such velocity, and that their operative parts be so formed and so arranged with relation to the other parts of the engine as to separate the fibers by a picking, snapping, whipping, or tearing action, as contradistinguished from grinding, cutting, or abrasion.

The process, again, according to the nature of the stock to be worked, may be carried on in an open vat or in a closed chamber, and under pressure, thelatter mode of working it being specially adapted for the more refractory substances, which may be found to require a high temperature to fit them for the most eificient action of the pickers.

It is not proposed, therefore, to limit the invention to any particular form or dimensions in the construction of the engine, since them..- vent-ion consists in a process rather than in The accompanying drawings show the application of the invention to a closed engine.

The modifications of structure that accompany its application to the ordinary open-vat pulp-engine are designed to form the subject of a separate patent, application for which is made of even date herewith.

Referring to the accompanying drawing, Figurel is a vertical section on the line a; w of Fig. 3. Fig. 2 is a vertical section in a plane at right angles to that of Fig. 1, and Fig. 3 is a horizontal section just above the feed-screw.

'The engine here represent-ed consists of a cylinder, of iron or other suitable metal, six feet in diameter and eighteen feet in height, or it may have such other dimensions as may be deemed expedient, and it should be of sufficient strength to withstand the required internal pressure. Of course it should be provided with a safety-valve with steam-gages and other appliances necessary upon ordinary steam-boilers. This cylinder is set in a vertical position, and is divided throughout the greater part of its height by a diaphragm, forming it into two compartments, which, however, communicate with the each other at the top and the bottom, as shown in the drawing.

In the upper part of the cylinder and over the right=hand compartment are arranged the pickers or strikers. In the space beneath the diaphragm, and arranged at right angles to the plane thereof, is placed a shaft, upon which are supported one or more propeller-blades, which are designed for feeding the material through from one compartment to the other. Surrounding the first-named cylinder and com centric with it is another of somewhat large diameter, and extending up to about the level of the lower part of the pickers.

The space between the two cylinders is designed as a hot-air flue. By placing vertical flue-strips in this annular space, in the plane of the diaphragm before spoken of, and building a fire under. the bottom of the right-hand compartment, the smoke pipe being at the same time placed on the other side of the fluestrips and near the bottom of the annular space, the heated products of combustion will be caused to ascend in contact with the wall of the right-hand compartment and descend along the wall of the left-hand compartment, and thus, as the currents within the cylinder are ascending on the right of the diaphragm and descending on the left, the heat can be made not only to increase the temperature of the water, but also, to some extent, to assist the circulation.

The pickers here shown are a gang of disks arranged upon a shaft above that compartment in which the currents are ascending, the peripheries of the disks being armed with long teeth. These saw-toothed disks are of thin metal, preferably of steel, and by means of collars are adjusted at a distance of about seven-eighths of an inch apart. The teeth'are bent laterally at various angles of inclination, so that, when moving, the several paths will, so far as possible, be out of the same line of travel. The edges of the teeth are notmade sharp enough to cut the fibers, but the points are so constructed as to pick and pull or tear the fibers apart, thus leaving them much stronger than if they had been cut or broken by grinding or abrasion between antagonizing surfaces. These pickers are so arranged at the top of the right-hand compartment as to dip but partially into the surface of the water, and thus they can have imparted tothem a much higher velocity than would be possible were they submerged, and, it is believed, can thus be made to act more uniformly upon all parts of the pulp.

Both the pickers and the feed-screw may be operated by connection with any suitable motive power, the connection being effected in any of the well-known modes.

In the top of the cylinder is a man hole, provided with a cover, and a discharge orifice or orifices for drawing off the charge may be provided at any convenient point in the side or bottom of the cylinder.

Referring to the drawings, A represents the main cylinder B, the jacketing-cylinder; O, the diaphragm; vD, the pickers; E, the screw;

. F, the fire chamber and grate; G G, the fluestrips; H, the smoke-pipe5 and J, the man hole. S is a pipe, by means of which steam may at any time be admitted to the cylinder.

The operation of this engine is as follows: After the cylinder is filled with water to the requisite height, the cut wood or other-material is poured in by the manhole while the engine is at rest, or is running slowly. The' man-hole isthen closed and the speed of the engine increased,'when the revolution of the pickers in the direction of the arrows draws the fibrous material and the water away from below andthrows it up over the upper part of the. diaphragm or septum, into the left hand-compartment, where it descends to the lower aperture in the diaphragm, through which it returns to its starting-point, and thus it is kept in constant circulation and is rapidly pickedv to pieces.

This circulation, as already indicated, may be aided by the screw-bladed shaft placed in the bottom of the cylinder; but any other suitable device for the same purpose may besubstituted for this, or it may be wholly omitted and still a sufficient circulation for most practical purposes be maintained by the combined action of the revolvingpickers and the gravity of the material.

\Vhen wood and other refractory substances are being treated, steam may be let on by the pipe S below, and this, blowing up the righthand side of the diaphragm, accelerates the The steam also contributes to circulation. create and maintain the requisite temperature and pressure.

\Vhen the temperature ard corresponding pressure are raised to the requisite degree to dissolve the sileX, the pickers are to be run very rapidly until the material is thoroughly reduced. The knots, on account 'of their greater inertia, are torn to shreds and reduced to their ultimate fibers as quickly as any other part of the material, and in all cases the largest pieces are acted on with the greater violence, the result of which is a marked uniformity in the pulp produced. So far as concerns the principle involved in this operation,

it is manifest that the two compartmentsin which, respectively, the stock is ascending and descending, instead of being separated by a simple diaphragm, may be placed at agreater distance apart, provided, only, that they are constructed with suitable connecting trunks or conduits at the top and bottom. Thepickers, whether in the closed chamber or in the open vat, will ordinarily be run with a speed of from five thousand to eight thousand feet per minute, and as the resistance to their blows is furnished by the inertia of the material, as supported in a fluid of great mobility, it is evident that a high speed is absolutely essential before the pickers can become efficient in separating the fibers. It is found in practice that with the substances at present used for paperstock, the pickers must be made to move at a rate of not less than from about twenty-five hundred to three thousand feet per minute, which is very largely in excess of the speed of the beating-roll in an ordinary pulpeengine.

In the closed engineshown in the drawing, the relative position of the pickers and the water is much the same as that of an undershot water-wheel to the stream by which it is driven; and this relative position will be main-- tained in applying the invention to the ordinary open-vat pulp-engine. Substantially the same principle of 7 operation, however, would be involved if the water which carries the stock were made to flow against the side or upon the top of the structure constituting the picker mechanism, after the manner of breast-wheels or overshot-wheels. In such cases it would probably be found necessary to cause the pickers to revolve in the reverse direction from ordinary breast or overshot millwheels when driven by the current, in order to prolong the contact of the pickers with the stock; but the reduction of the stock would still be effected by the percussive and tearing action of the picker-points, and not by the grinding, abrading, or cutting action. heretofore relied upon in the engines in which the reduction has been effected by mechanical means. The pickers, whether working in the common open vat or in a closed vessel, do not 7 cut the fibers in pieces or grind and injure them, as the common mills do; but they pick,

whip, and snap them out with but little waste of their strength. All' of the beating and grinding processes heretofore in vogue tend,

more or less, to bruise, break, cut, and pulverize the fiber. The new process, on the contrary depends entirely upon the percussive and tearing action of the pickers or strikers, which are so constructed, and so arranged in relation to the other parts of the mechanism, as wholly to avoid the grinding action of opposingsurfaces, as well as the cutting and abrasion produced by the action of blades revolving over" or against other and resisting blades or surfaces, in such a way that the material is caught between the two sets or series of blades, and thereby cut or shredded to pieces.

The present invention is distinguished from that for which a patent was granted Azel Storrs Lyman on the 4th day of March, 1862, entitled an improved process of separating the fibers of wood and other substances for the manufacture -of paper pulp, in which there was showna series. of so-called beaters, that revolved in contact with the material-to be reduced. Not only the construction and the arrangement, but the function of the heaters there shown was essentially different from that of the pickers employed in the present invention. The primary function of those heaters was simply to feed the material to the cone-shaped grinding-mill,and for this purpose they were arranged spirally upon the shaft of the grinding-cone. This function also required that they should be entirely submerged, so that, even if made of different shape, it would have been next to impossible to give them suflicient rapidity of revolution to render them efficient to reduce the material. a form least adapted for disintegrating the substances from which paper-pulp is produced. In all these particulars the present invention is materially different from anything described or known in the patent named. By the former They were also made with blunt edges,

process, the stock was to be reduced by the grinding-surfaces, which constituted a part of the mechanism shown. B y the present process, the work is' done by the percussive and tearing action of the pickers, the stock having no other support when the pickers strike it than What is afforded by the yieldin g fluid in which it is floated.

WVbat I claim as new is- 1. The process hereinbefore described of disintegrating fibrous substances, the same consisting essentially in subjecting them, while held in suspension in or mingled with Water or other liquid, to the percussive and tearing action of rapidly-movin g pickers or strikers, the

resistance to the blows of which is furnished by the inertia of the material under treatment, and of the medium in which it is moving.

2. A fiber-reducing engine, constructed with two vertical compartments or trunks which communicate at top and bottom, as set forth, and one of which is provided with a series of pickers or strikers, constructed and arranged to operate substantially as and for the purpose described.

AZEL STORES LYMAN.

Vvitnesscs:

SAML. A. DUNCAN, BENJ. A. SMITH.

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