US1785544A - Process and apparatus for disintegrating wood - Google Patents

Description

Dec. 1s, 1930. l G. H. ELLIS 1,785,544

PROCESS AND APPARATUS FOR DISINTEGRATING WOOD Filed Jurf 27, 1927 BL'IORNE: V

Patented Dec. 16, 1930 UNITED STATES PATE-NT OFFICE GEORGE H. ELLIS, OF ST. PAUL, MINNESOTA, ASSIG'NOR TO THE INSULITE COMPANY, OF MINNEAPOLIS,v MINNESOTA, A CORPORATION OF MINNESOTA PROCESS AND APPARATUS FOR DISINTEGRATING WOOD Application led .Tune 27, 1927. Serial No. 201,939.,

This invention relates to an improved process and apparatus for disintegrating wood chips or separating Wood fibers in preparing them for use in the making` of wood pulp stock, such as is u sed in the manufacture of paper, insulating material, and various other products. Y

An object ofthe invention is to provide an improved process which consists in alternately compressing the chips and allowing them to absorb water until the fibers are loosened from one another or are separated into integrant parts.

`A further object is to provide an improved i process for disintegrating wood chips which consistsin passing the chips between a pair of submerged rollers to squeeze or force the air and water out ofthe Wood, then allowing the squeezed chips to expand and absorb Water and repeating the operationI until 'the chips are disintegrated.

A further object is to provide an apparatus for disintegrating wood chips comprisingl a fluid tank having means therein for heating' the fluid, and further having a plulrality of rollers mounted therein and arranged in pairs, one pair over another, and a series of water chambers alternating with said rollers, and through which the wood chips are progressively passedto cause the fibers thereof to become separated into integrant parts. Broadly,the process consists in first passlng air dried lwood chips between a pair of 35 submerged rollers and compressing them to remove the air from the wood; then discharging the wood chips into'a confined water chamber and allowing them to expand and absorb water, after which the compress- 40 ing and expanding operations are repeated until the fibers become separated. By thus compressing the chips and allowing them to expand under water, preferably hot water, the water is dawn into the cells or interstices between t e fibers of the chips. In taking the water into the interstices` of the chips, the lignin and resin are more or less softened, and, when the water soaked chips areY compressed, the water, being noncompressible, is forced out very rapidly and, in so doing, tears the chips asunder and shreds them into small long bundles of fiber, after which tliewood fibers may' readily be separated and mixed with a suitable fluid, such as is used in the preparation of' fibrous .pulp-'stocln The particular object of the invention y therefore is to providev an improved process and apparatus for disintegrating Wood.

Other objects' of the invention will appear from the following description and ac-l companying drawings and will be out in the annexed claims.

In the accompanyingdrawings, there, has been disclosed a structure designed to carry pointed out the various objects of the invention but it is to be understood that the invention is not confined to the exact features shown, as lvarious changes may be made Within the scope of the claims which follow.

The accompanying drawing illustrates an apparatus adapted for use in connection with my improved process.l p

In the accompanying drawing, there is illustrated an apparatus adapted for use in connection with' my improved process for disintegratingwood chips. This apparatus comprises a fluid tank 2, preferably having a depressed portion 3, wherein a shaft 4 is mounted, and upon which sprocket wheels 5 are secured which` function to support the lower portion of an endless conveyer belt 6, as shown. The upper portion of the conveyer issupported by means of sprockets 7 secured to as'haft 8, mounted in brackets 9, preferably secured to the upper portionsof the walls of the tank. A chute 10 is provided to receive the disintegrated wood chips, as theyare discharged from the bucket eonveyer 6.

An important feature of this apparatus resides in the means provided 'for squeezing or pressing the wood chips, as they are passed therethrough. A pair of rollers 11 and 12l cated by the arrows. A second pair of rollers 15 and 16 are mounted below the rollers 11 and 12, and are similarly geared .together for simultaneous movement. Similar rollers 17 and 18 are preferably mounted below the rollers 15 and 16 and are likewisegeared to ther forl simultaneous movement.

e conveyer 6'y may be operated by a suitable belt drive 19, operatively ,connecting the shaft 8 with the ,rollersha'ft 14. The rollers 15-16 and 17-18 are also preferably driven from the shaft 14 by means of suitable gears 21, 22, and 23, indicated in dotted lines. The gears connecting together each pair of rollers are of ordinary, well-known construction and it is therefore thought unnecessary to show same in the drawing, it being understood that the rollers are rotated in the direction indicated by the arrows.

A hopper 24 is suitably supported upon the walls of the tank and rovides means for feeding Athe wood chips getween the upper p air of pressure rollers 11 and 12.

Referring to the drawing, it will be noted that a substantially closed water chamber is provided between each pair of rollers. These water chambers are defined by the peripheries of the rollers and the spaced wall portions 25 and 26, having their end suitably secured to the side walls of the tank.

In the operation of this novel apparatus;

the wood, after having been passed through lthe result that the fibers are a chopper or cutter and reduced into comaratively small chips or pieces, is delivered into the hopper 24, after which the chips are fed downwardly between the upper pair of rollers and into the upper water chamber 27. Asthe chips pass between the rollers 11 and 12, the air contained therein, as a result of the chips being substantially dry, is squeezed out of the chips. As soon as the squeezed chips are discharged into the water chamber 27, they immediately begin to expand or tend to assume their natural shape,'thereby drawing water into the interstices between theibers thereof. These water-soaked chi s are then passed between the second pair o rolle-rs 15 and 16, thereby subjecting them to a second rapid compressing operation which rapidly forces the water out of the chips with artiall loosened or torn asunder before belng disc ar ed' into the second water chamber 28 where t 313i with water. The 'chips are then passed through the lower pair of rollers where the' water is again quickly forced out of the chips with the resultant loosening or separating of the wood fibers into separate integrant parts. By the time the wood chips'have progressively and alternately passed through the series of pressure rollers and water chambers, all of the air has been removed therefrom so that the disintegrated chipsno lon er tend to rise or lioat in-the water, but s' to the bottom of the depression 3, where they are intercepted by or received in the buckets of after which the fibers are more readily separatcld. l

In actual practice, it has been found that by alternately passing wood chips through a Aseries of -pressure rollers and water chambers, such as above described, that the iberso'f the chips become loosened or freed from one another so lthat the chips, after being discharged from the lower set of rollers, appear very much like bundles of fibers, as each chip will be substantially intact but the fibers thereof will be loosened from one another so that they may readily be se arated. It has also been found t at three sets of pressure rollers and two water chambers, arranged substantially as shown on the accompanying drawing, is suicient to thoroughly disintegrate the chips when passed therethrough. It is to be understood, however,l that for certain grades of wood, it may be necessary to use a greater number of airs of rollers, or, it may be necessary to ispense with onev air and use only four rollers. The process odisintegrating the chips, however, remains the same. It may also be necessary, when disintegrating certain kinds of wood, particularlythe fatty grades, such as yellow pine and tamarack, to use a solvent ysuch as alkali, or sulphate liquor, in order to'obtain the desired degree of dislntegration. If the water in the chambers in which the chi s are allowed to expand, is alkaline or aci this alkali or .acid will be drawn into the interstices of the chips and will therefore act upon the resins, gum and lignin, which will tend to hasten disintegration and will im art to the chips a softness whichtends to ree the fibers, after which the fibers will havel the characteristics of fibers which have been treated in a digester with the same chemicals. By the employment ofthis novel process and apparatus, the operation of dismtegratlng wood chips in preparing them for fibrous able, especially where the of any importance.

A very important feature of the present invention relates to the process for dividing Wood for producing pulp board or analogous products, particularly production from certain classes of Woods, including woods having the bark thereon, not heretofore usable in the manufacture of pulp products. The present process permits the use of waste products `of the saw mill called slab wood containing bark, as well as certain other waste woodsf, the texture, or chemical composition, of which has heretofore made them unusable. One of the important steps in t-he process is compression and release in Water or in a chemical solution, by means of which, as the result of what may be termed pumping action, the Water or the solution is sucked or brought into the interstices of the wood. The idea of taking advantage of that mechanical function of the Wood by which the bers tend to resume their original expanded condition after compression, and as a result of which chemicalmaterial can be sucked within, to assist in separating the bundled and cemented fibers, is believed broadl new. B continued experiment, it has een foun that libers of various soft woods can be successfully separated, -without destroying their binding properties for the use in hand. For example, it has been heretofore considered unprolitable to attempt to utilize Waste cedar, cut from the butt ends o f cedar poles and posts. Mechanical-processes have been failures due, it is believed, to the frangible, silk like fiber in the cedar, and due to persistent' cementation of the fibers. The abrasive action of the grinds'tone completely destroys this liber, Cooking processes have been attempted, but these are unprofitable. Another wood which is usable, when subjected tothe present pro cess is balm of Gilead, which has an excellent long line liber, but has not been used for paper making or for lumber, and is generally left to decay. Neither grindstone nor chemical treatment has made this wood usable commercially.

The slab wood above mentioned contains a large percentage of bark and heretofore lthis wood has not been usa-ble because there is no profitable method for removing. the bark from the slabs. The present process has made it possible to use this wood for mequestion of room is chanical pulp or chemical pulp, and has madev it possible to remove and ydispose ofthe bark economically.

As before stated, these waste woods as well as other woods may be properly condi tioned for the purpose in hand by being chipped into pieces of a size ordinarily used for chemical pulping, and'then pressed, (to.

drive out the air and put the libers under tension) and subsequently allowed to expand,

making it unsuitable for any use.

preferably in some lluid medium, or in a chemical solution, for instance, in an alkaline solution, which will act to neutralize wood acids, allowing the libers of 'the wood bundles to be separated without such corre-I sponding breaking up of the libers as will destroy their binding qualities. If a chip becomes soft as the result of softening of cementing materials therein, the rapidity with which the liuid is driven out of the chip may be increased so that the outgoing fluid, or chemical medium will shred or split the chip into small bundles or into separate libres. If the water is hot, the action is quicker. It has been found that by varying the amount of alkali, that the cementing materials are softened to a greater degree than with hot water alone and remain soft `for a longer period. In other Words, if cold water is used the action is very slow and the resultant liber isshorter than if hot water is used. If a hot solution of alkali, or of an acid which will neutralize the cementing materials, these materials are softened in less time, with less injury to the fiber; This reduction of time, and pulling apart of the liber without undue disintegration V-or breaking, are important features df the invention and of the process.

The following woods havebran successfully reduced to liber in such a manner that q (in the case of unbarked slab wood) disintel grates the bark which is more tender than the liberl and, it is believed that atleast a certain portion of the bark is held as an emulsion, or in suspension or solution in a finely divided state. After the cementin materials aresulliciently softened and vt e chip reduced to shreds lor to small bundles of liber, it is passed to the pulp-ing machine. It is apparent that the attritional or rubbing action which takes place, further reduces the bark which is thus separated from the liber.

The pulp produced by the present process can be washed in any of the well known devices used in paper making, and a large percentage of bark is removed in the washing, process. Ithasbeen found that` the water rst leaving, has a dark' brown appearance and. contains bark. Of course, it is evident thatwith this process, it is unnecessary to debark the wood, and in this way the entire tree can be converted into'pulp.; This is an accomplishment at present unknown.

l The important steps in the present process are compression, release and expansion of the batch in the presence of chemical substance such as Awater or a chemical solution of a nature to soften and assist in disinte rating the fibers. To recapitulate: the sla wood 'or waste wood containin considerable wood cementin material an having bark is first chippe to a suitable size. The chipped or sized material is then introduced into an alkaline solution, or water, gr a suitable chemical solution, or a suitable absorbable chemical material of any kind, and the sized material is compressed while within'this solution or chemical material. The 'wood is then released, and in an attempt to expand to its normal condition', the chemical substance is sucked inwardly, and apparently an intimate mixture, resulting in chemical change,:takes place to soften and separate the fibers, withoutthat disintegration, which often, in the old processes, untted the material for further use. The separated, neutralized batch is then ground to a suitable neness, and the mass is then washed to remove the bark which apparentl goes into solution and is drawn oi with t e wash'liquid.

I claim as my invention:

1. A process of disintegrating wood chips which consists in passing the chips b'etween a pair of rollers submerged in liquid within a suitable receptacle, to force the air out of the wood, then allowin to expand and absorb te liquid, and imme. diately subjecting the liquid-soaked chi s -to a second pressing 'operatlon to quickly orce the liquid o'ut of the chips to separate the fibers.. l 2.' In anap'paratus for disintegratin wood chips, the Vctmibination of a fluid tank aving means therein folieatin the fluid, rollers mounted 1n pairs in sai tank, means. for

.feeding wood chips between the lfirst pair of rollers, and a series of conned water chambers alternating with said pairs of rollers through which chambers, said chips are progressively passed to absorb the fluid therein.

3. In an apparatus for disintegratin wood chips, the combination of a uid tank having means therein for heating the fluid, pairs of rollers mounted therein, in superposed relation and normally .submerged in the fluid, a hopper for feeding wood chips between the top pair of rollers. a series of confined water chambers alternating with said pairs of rollers and through which chambers, said chi s are progressively passed and allowed to a sorb fluid, and means for removing the disintegrated wood fibers fromsaidtank.

4. In an apparatus for disintegrating wood `-chips,.the combination of aluid tank, a pair of rollers mounted therein and submerged in the fluid, means for feeding wood chips between said rollers to squeeze the air theren the squeezed chips -.quently squeezingthe pieces receive said Huid-soaked chips from saidv chamber and'functioning to forcibly squeeze the fluid therefrom, a similar chamber arranged beneath the second air of rollers through which the squeezed c ips are passed and allowed to again absorb water, and means beneath said last mentioned chambery for subjecting the chips to another squeezing operationr to forciblysqueeze the fluid therefrom and whereby the wood fibers are separated into integrant parts.

5. An apparatus for disintegrating wood, comprising a suitable tank having la liquid therein, a plurality of pressure ymeans mounted in said tank and substantially sub.- inerged in the liquid therein, and a closed chamber between said pressure means adapted to be traversed by the wood.

6. An apparatus for disintegrating wood,- comprising -a suitable tank having a liquid therein, a plurality of pressure means mounted in said tank, and through which the wood is progressively passed, there being confined areas between said pressure means contain.-

inlayl liquid into andbeneath the surface of which the partially disintegrated wood is discharged from said pressure means and allowed to absorb liquid. l'7. An apparatus' for separating wood bers, comprising a tank adapted to contain said tank. means for feeding woodchips between'. said pairs of rollers, there being conned areas between adjacent pairs'of rollers adapted tocontain liquid into and beneath the surface of which the 'partiallvvdisintegrated wood chips are discharged from said rollers and allowed to expand and absorb liquid. as the chips are passed fromone pair of rollers to the next. 8. process for disintegrating wood which consists in passing the w'oodsbetween oppositely rotating members while the wood is vsubstantially submerged in a uid medium to force the air outof the wood, then allowf ing the squeezed y A. fluid', and subsequently subjecting the Huidsoaked chips to-a second pressing operation to..

quickly force the fluid out ofthe woodto' separate the ber's, the second pressing opera-` tion following immediately after-the first.v

9. A process of disintegrating pieces of .wood which consists in squeezing vthe pieces while submerged in a suitable iluid, .to force a suitable liquid, pairs of rollers mounted in wood to expand and absorb air out ofthe pieces, then allowing the pieces to expand and absorb-'the duid, and subse-V a second time to pores and thereby eject theiluid from the` separate the -wood fibers, the'- second squeez-4 ing operation following immediately after the rst.

10. An apparatus for disintegrating wood, comprising a suitable tank having a duid therein,spacedapart pressure means mounted in said tank, there being a substantially closed chamber between said pressure means adapted to be traversed by the wood as it lpasses from one pressure means to the next.

w l1. An apparatus for disintegrating pieces of wood, comprising means for squeezing the pieces to'eject air from the pores thereof, said apparatus having a-'substantially closed liquid-containing area adapted to receive the squeezed wood pieces and allow the pores in the wood to fill with liquid, and means for expelling the liquid from the pieces to separate the fibers thereof. v

12. A process of disintegrating wood which consists in compressing the wood between rotating members whi e under water to remove air therefrom, then allowing the wood to expand and absorb water, and immediately subjecting the water-soaked wood to a second pressing and expandin operation whereby the bers are separated.

13. In an vapparatus for disintegrating wood chi s, a .fluid tank, a pair of rollers mounted t erein, means for feeding the wood chips between said rollers, a second pair of rollers spaced from said first mentioned rollers, there being a substantially confined area between said pairs of rollers providedwith a liquid into and beneath the surface of which 85 the squeezed chips are discharged from the first pair of rollers, whereby the air-exhausted pores of the chips will absorb liquid, after which said liquid-soaked chips willpass between the second lair of rollersand the liquid again squeezed t ererom, thereby causing the fibers to separate.

14. A process of disintegrating brous material which consists in subjecting the material to a series of compressions one following immediately after the other, and subjecting the material to moisture between compressions.

15. An apparatus for disintegrating wood chips, comprising a receptacle adapted to cont-ain liquid, chip-compressing means arranged to successively squeeze the chips, means for feeding the chips to said compressing means to expel the air from the pores of the chips, there being areas provided in the liquid between the compressin means to rece'ivef the chips :following eac compression thereof, whereby the air-exhausted pores of .the chips will absorb moisture following each squeezing operation. -A

In witness whereof, I have hereunto set my hand this 25th day of June, 1927;

GEORGE H. ELLIS

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