US1883876A - Preparation of fiber and fiber pulp - Google Patents

Description

Get. 25, 1932. BRQWN 1,883,876

PREPARATION OF FIBER AND FIBER PULP Filed Sept. 2, 1930 2 Sheets-Sheet l INVENTOR WITNESSES 95 W BO erliflrowzz,

ATTORNEYS Oct, 25, 1932. 3, BROWN 1,883,876

PREPARATION OF FIBER AND FIBER PULP Filed Sept. 2. 19-30 2 Sheets-Sheet 2 WITNESSES INVENTOR ATTORNEYS Patented Oct. 25,

UNITED STATES PATENT-germs ROGER 3. BROWN, OF TREN'I'ON, NEW JERSEY, ASSIGNOR TO DANIEL HANSON SUTHEBLAND, JR., OF MORRISVILLE, PENNSYLVANIA PREPARATION OF- FIBEB AND FIBER PULP Application filed September 2. 1930. Serial No. 479,251.

My invention relates to the preparation of fiber and fiber ulp for paper, artificial board, and other iiber products, particularly from fibrous material of woody character.

Hitherto,mechanical 'wood pulp has been produced by grinding round wood on stones, and a comparatively'small amount is produced by attrition mills equipped with metal plate grinding surfaces The pulp produced by these processesis short, and does not have the maximum fibre length existing in the original wood; on the contrary, the pulp comprises fibres so short as to be known to thetrade as flour, so that it is low in freeness and strength. To make this mechanical 'pulp suitable for paper, it must be mixed with chemical pulps, such as sulphite, in order to get sufiicient strength. F urther- 'more, the grinding operation commonlyaemployed requires approximately 60 H. P. days per ton of pulp, and at least 85% of th s power goes into heating the water used during the grinding operation.

I have discovered a way of producing a much better mechanical pulp with a much smaller expenditure of power. Pulp proslivers or bundles of fibers from .a billet or piece of wood, as hereinafter described, and

then by laterally tearing apart component A made quite as fine as in the old wood flour; but their length remains much reater, because a large part of the total wor of lateral separation has been accomplished without very much breakage of the ultimate fibers.

In the drawings, Fig. I is a plan view of a machine for shaving ofi fine slivers or fiber bundles from wooden billets,whether round wood, slab wood, or any othef suitable pieces.

Fig. II shows a fragmentary vertical section through one of the operative units of the machine, taken as indicated by the line and arrows II-II in Fig. I.

duced according tom invention can be made Fig. III shows a vertical cross-section fibrous instead of oury, with long fibre length, 7 good felting properties, hlgh strength, and yet with quick draining properties or high freeness. When stopped short at an intermediate stage, moreover, my process affords a new and advantageous method of producing a long wood fiber stock that is directly useful for many purposes without further reductionas for the manufacture' of coarse-fibered board for building,

thermo-insulative, and acoustical purposes, for example. In my new process, I avoid initlally breaking the natural fibers ofthe wood mto short lengths, as is done in wet-grinding as described above. the natural fibers from one another laterally,

at their natural cleavages, leaving them as I long as possible,very much longer, indeed,

than it is desirable to have them in pulp for making paper. Such lateral separation of fibers may be efiected in a succession of steps, first preferably by shaving ofi thin On the contrary, I separate.

through one commercial form of shredder, of the hammer mill type,'suitable for further reducing the fiber bundles from the machine of Figs. I and II.

individual fibers in the final productmay be I Fig. IV is a side view of a commercial form I fiber bundles to pulp.

In the machine hereillustrated, fibrous ma terial such as wood is acted on by rapidly revolving cutters or scrapers 10 to which the of attrition mill suitable tor reducing the lets are generally obtained. These slivers can afterward be further treated to reduce or disintegrate them to still, smaller aggrewood is continually or repeatedl presented.

' at 13, and has a plurality of radially extendmg hoppers or pockets 14 for the billets W. The cylinders 11 are arranged in a circular series concentrically with the carrier 12, and

extend radially. With the revolving cylinders 11 is associated a table or shield 15 that sustains the billets W in the intervals betweenthe c' linders md has openings 16 for the latter ig. II). The carrier 12 may be revolved slowly (e. g.,.at about 2R. P. M.) by any suitable means, such as an electric motor 17 with reduction gearing 18 and a pinion 19 meshing with an external rack 20 on the carrier.

The motor 17' and gearing 18 are shown mounted on a platform or shelf 21, suitably secured and supported. The cutter c linders 11 may be rotated rapidly (e. g., a out 3600 R. P. M.) by any suitable means, such as individual electric motors 23, mounted around the machine as hereinafter described,

and each directly connected to its corresponding cylinder 11. The slivers or shavings cut from the billets W by the cutters 10 fall through the openings 16 in the table 15 into any suitable receiver (not shown). 'In detail, the machine may be constructed as described in the concurrently filed application of Francis S. Farley, Serial No. 479,401, assigned to the assignee of this application.

In the operation of the machine, the carrier 12 is slowly rotated by the motor 17 while suitable way.

table 15 the cutter cylinders 11 are rapidly revolved by the motors 23. Billets of wood W are fed and-dropped into the pockets 14 from the platform 21, ea ,by hand or in any other s the billets W at the bottom pocket 14 are pushed around on the y the carrier 12, thin slivers are cut from each billet at successive tangential implngements with each of the rapidly rotating of each -'cutters 10, in the manner indicated in Fig.

II. Since the grain of each log or billet W 1s substantially or approximately parallel w1th the knife edge 10,as well as with the axis of revolution of each cutter 10,-as the billet is presented to the cutter in this man-' ner, the cutter divides the fibers sidewise from one another, without severing them as would be the case if the billet extended crosswise of the knife edge. The smaller the path of rev- -olution of the knife edge 10,'the lower the power consumption in roportion to the quantity and fineness of s ivers produced.

The projection of the cutters 10 above the table 15 controls and'determines the thickness of the slivers-produced, and may be varied by adjusting the height of the table.

The slivers thus. obtained are long, mar-- row, thin wooden ribbons, about to wide (more or less), about 1/100 to n. thick, and in many cases as lon as the b11- lets from which they are cut,w ich may be two feet long, conveniently.

These slivers or bundles of laterally adherent fibers are further reduced in any suitable shredding machine that will tear the fibers apart laterally without too much transverse breakage, such as the hammer mill shown in Fig. III. Bunches or sheaves of the longslivers are fed in sidewise down the sloping wall 25 over the impact plate 26, where they are struck tangentlally and torn to pieces by the rapidly revolving centrifugally influenced hammers 27 which are freely pivoted at 28 to their common rotary carrier 30. It will be observed that the impinging leading edges or corners of these hammers 27 extend in the direction of the grain of the slivers as the latter are fed in sidewise, as above described. As shown, the carrier 30 has'stops 31 at either side of each hammer 27, to limit their swing relative thereto. The resulting strands or shreds may be carried around in the machine over the plate 26 a" number of times, till they are reduced to a sufiicient de cc of fineness to be crowded out and disc arged through the sm'all openings of the foramino'us lower wall 32, beyond the plate 26, into the receiving space there-beneath.

The resulting shreds or fiber bundles vary considerably in size, but lie mainly between 1 in. and A in. long and in. to in. wide, and may average something like in. long or more by in. wide and a couple of hundredths of an inch thick i. e., the length is generally at least sixteen times the greater transverse dimension. This long-fibered stock is thus immediately suitable for-use in the manufacture of coarse-fibered board, for' building, thermo-insulative or acoustical pur-- poses, etc.

For the manufacture of paper pulp, I further reduce these shreds or bundles of fiber, preferably by a refining operation in the nature of wet-grinding. Any suitable refining machinery may be used for this purpose,

.such as the attrition mill shown in Fig. IV,

preferably with stone linings or grinding surfaces. For this purpose, the shredded wood is first leached or soaked in water until thoroughly saturated and softened, or even cooked if desired. Owing to the fineness of the shreds, they are better and more readily penetrated by the leachin liquid than are ordinary Wood chips. A ter leaching or cookin and while still wet, they are passed throug the attrition mill, being fed into the hopper which delivers centrally between the oppositely revolving grinding rotors 36, 37, which may be driven by belts (not shown) on pulleys 38, 39.

As here shown, the rotor 36 has an annular opening 40 from the hopper 35 therethrough, between its hub 41 and its outer portion which carries the annular grinding surface or stone lining 43. Spokes 44 across this opening 40'connect the hub 41 to the outer portion of the rotor. The rotor 37 is solid across its center, and has a grinding surface or stone lining 45 for coacting with the surface 43. Between the oppositely moving surfaces 43, 45, which are preferably grooved radially, the fine, long wet shreds are dis integrated or ground apart, mainly by lateral separation of their component fibers, but with some breakage of the fibers too. The thus ground fibers work their way outward peripherally from between the sur faces 43, 45 into the casing 46, whence they are discharged at, the openin 47, in the form of a fine, moist, long-fibere pulp.

If desired, this pulp can be passed through a series of such attrition mills, so as to carry its reduction on down to any desired quality of stock, according-tothe purpose for which it is to be used,

Having thus described my invention, I claim:

1. A method of converting wood into longfibered stock which comprises shaving long, narrow slivers or ribbons laterally from a billet, by successive tan ential lateral in1pingements witlra knife edge extending in the direction of the grain of the billet; and'shredding these slivers into finer strands by tangential lateral impingement of hammer edges extending in the direction of the grain of the slivers, so as to tear their component fibers apart laterally, with minimum breakage of the ultimate fibers.

2. A method of converting wood into fibrous paper-pulp which comprises shaving long, narrow slivers or ribbons laterally from a billet, by successive tangential lateral impingements with a: knife edge extending in the direction of the grain of the billet; shredding these slivers into finer strands by tangential lateral impingement of hammer edges extending in the direction of the grain of the slivers, so as to tear their component fibers apart laterally, with minimum breakage of the ultimate fibers; and only finally breaking the component fibers to the-desired ultimate length, as an incident of the final, refining stages of reduction.

In testimony whereof, I have hereunto signed my name at Trenton, New Jersey, this 25th day of August 1930.

ROGER B. BROWN.

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