US2130681A - Process and apparatus for deriving fiber from flax straw or the like - Google Patents

Description

Sept. 20, 1938.

PROCESS AND APPARATUS FOR DERIVINGFIBER, FROM FLAX STRAW on THE LIKE Original Filed July 23, 1931 1 b mm um um H1 Q 2 m .H .w/x mm It I 2 Sheets-Sheet 1 2 Sheets-Sheet 2 d flu w n .4 RN W 9w a A m m w m w w ww H Q Q\ 9w w N 2 0 o w o o W .k QQQ .WJ 7. o m o w o w mv owvw w a v N N% 0 v R. FORSYTH Sept. 20,1938.

PROCESS AND APPARATUS FOR DERIVING FIBER FROM FLAX STRAW OR THE LIKE Original Filed July 23, l931 Patented Sept. 20,

PATENT OFFICE PROCESS AND APPARATUS FQR DERIVING FIBER FROM FLAX STRAW OR THE LIKE mum Forsyth, crammin assignor to Robert N. Burton, Chicago, Ill.

Application July 23, 1931, Serial No. 552,618 Renewed November I, 1936 1 Claims. (01. 19-7) This invention relates to a process and to apparatus for performing the process of separating or deriving from certain vegetable stalks or stems the fibrous structure thereof in the form 5 of individual fibers. Such fibrous material is adapted for use in the textile art for spinning and weaving thread and cloth in the nature of linen; it is also valuable for the manufacture of certain grades of paper commonly known as bond" paper and for the paper stock employed for currency; another and quite different use for such fiber is for packing or wicking for which it is suitable by reason of its capillary structure and in which capacity it may replace the cotton waste commonly employed for packing journal bearings like those of railway car axles. These are only afew examples of the range of uses of such fiber. The process is designed and illus trated with respect to the treatment of threshed flax straw, or like material, in such manner that the entire straw can be made available for use by --separation into itscomponent parts including the Woody portion or shive, the gum and resin, the tannin and chlorofyl and the fiber itself.

An object of the invention is to provide a process and apparatus for mechanically accomplishing this purpose; another object is to insure a relatively gentle treatment of the fiber throughout 3 the process so that it shall retain all of its original tensile strength and other desirable qualities without the impairment which might result from excessive chemical treatment or rough mechanical handling; another object is to maintain the fibers as far as possible in their original unbroken length and in substantial alignment through the process to avoid tangling and breakage; and it is also an object of the invention to provide a substantially continuous process adapted to op- 40 elate on a definite time schedule whereby a given plant may be depended upon to turn out a known quantity of finished fiber in a given time with the various steps of the process under definite control at all times. Other objects will appear 5 as the description proceeds. The invention therefore consists inthe various steps of the process in combination and in certain features and elements of the apparatus and the relative arrangement of the parts thereof, all as hereinafter 50 described and shown in the drawings and as indicated by the claims.

Figure 1 is a diagrammatic side elevation of the apparatus for the initial steps of the process including a feeding belt, flattening rolls and ad- 55 ditional rolls for flexing the straw and a picker of the dry fiber.

of typical construction, all for treating the straw in the dry state.

Figure 2 illustrates diagrammatically in vertical section the first series of troughs in which the fiber is treated for softening the gums and 5 resins and also squeezing rolls associated with said troughs, together with a portion of the second series of troughs from which the material is fed from'the rolls.

Figure 3 is in'effect a continuation of Figure 2 10 showing the terminal portion of the second set of troughs with additional squeezing rolls and also a neutralizing acid bath, a rinsing water bath, the final squeezing rolls, a traveling dryer belt and a set of rolls for mechanical softening 15 Figure 4 is a diagrammatic detail mainly in section, showing the corrugations of the fiexing rolls illustrated in Figure l, and including. one of the hook shaped picker teeth to which said 20 rolls feed the straw.

Figure 5 is a transverse section of one of the tanks or trough assembliesQbeing taken substantially as indicated at line, 5-'5, on Figure 2.

Figure 6 is adetail elevation of the squeezing 25 rolls shown in Figure 2.

Figure '7 is a detail section on a larger scale showing the construction of the troughs of Figure 5. t

Figure 8 is a partial plan view of said troughs. 30

This process having been designed primarily for the treatment of flax stalks or straw and particularly for handling thrashed flax straw, will be described with reference to that material although it may be understood that the process 5 may be suitable wholly or in part for deriving the fibrous content of other similar plant growths. It may be understoodthat the process is designed primarily to employ the straw shortly after the threshing process has been completed, 40

but preferably with the straw thoroughly dried.

Thatis, it isnot intended or contemplated that the straw shall be retted as was once the practice, by permitting it to partially rot on the i ground or under water to allow deterioration of the wood portion,

since such treatment has a tendency to deteriorate and weakenthe fiber itself as well as to waste the woody material or shive which itself has a definite value, as for use in various wood pulp products, including news print.

Assuming then that the straw is supplied in a dry condition, it is fed by any convenient means such as by a conveyor belt, I, for delivery between a pair of plain rolls, 2, 2, which serve to flatten the straw and tend to split the fibers apart to some extent, and partially break up the woody material adhering to them. For further loosening this material, the, straw passes'directlybetween several pairs of fluted rolls whose grooves or corrugations are smoothly rounded and extend longitudinally, that is, parallel to the axes of the rolls and without any sharp edges. Four pairs of such rolls are shown at 3, 4, 5 and 8 in Figure 1, and

from Figure 4 it may be noted that these rolls are ance space between the first pair of rolls is greatseries.

' er than that between construction,

as a suggestion in dotted outline two the second pair, while the width of the flutings and the clearance space between the flnal pair of rolls, 6, 6, is the least in the The purpose of this arrangement is to cause the rolls to mildly fiex the straw as it passes through them, tending to break the woody portions into short-sections and to loosen them from the fibers themselves, ly more severe when vthe straw reaches. the final set of rolls, I, 8, than when it enters a set of rolls, 8, I. As a result of this treatment the fibrous stalks shed a considerable portion oitheir woody content or "shive" before they reach. the drum, 1, of the picker, 8, and are caught up by the hooklike teeth, I, 0! said drum to be carried through the picker. This machine may be similar to those used for a like purpose and of generally standard it being'u'nder'stood that its function is to comb the fibrous material by means of toothed rolls-tendlne'to split the fibers apart and straighten themout and at the same time serving to break oil most or the-remaining fragments and particles of the woody material or shive. Merely for the pickerJ, I have indicated pairs of so-called "working" rolls at II and I4, and a final large delivery roll or drum, II, by which it may be understood the fiber is discharged over a suitably inclined chute or table, it, into a receiving basket or car, It.

The dry fiber which isthus loosely piled or coiled in the receptacle, l3, may be-accumulated' as desired, as for example, until the receptacle is well filled, at which time the accumulated fiber will be definitely which continues another receiving car or basket being placed in position and the first car being wheeled to the receiving end'of the tank, l4, at A. The cut or broken ends of the bunched or assembled to form a "silver" which may be started through the trough-like structure of the tank, I4, either by tying it with a string and leading the string through the feed rolls, ii, at the opposite end oi the tank, l4, or by leading the sliver" itself through the tank and'starting 7 its end portion through these rolls, l5. It is desirable, however, that the fiber shall experience a soaking treatment in the heated water bath of the tank, l4, for a period of at least thirty-five minutes; therefore, if the lead string is not employed, the sliver will be merely drawn through the length of the tank, i4, and allowed to lie there for this period before being started through the feed rolls, II. f

The tank, l4, as more clearly indicated in Figure 5 consists of outer side walls, I1, and a bottom wall, l8, within this treatment being slight- -insure the treatment cut or brolren .ofi' from thatto discharge from the picker,

fiber in the receptacle, ll, are

said rolls aligned with the several troughs, It, and

which are shown longitudinally the side walls, I I, with communication ports or opening tom. Near the top of the tank and below the upper edges of the side walls. II, a series of longitudinally extending troughs, 2|, aresupported on wardly between the sidewalls, l8, and their adiacent bailles, II, and thence horizontally over the troughs, 2|, and downwardly through their perseveral so called "slivers" will be disposed in the or assemblies of fibers 7 respective troughs, 2!, as many as three slivers to'each trough if dedred, and that as soon as these tered in the feed rolls, II,

F. and 212 F. by means ofthe livesteam in the pipes-24, andthe convection currents set up in the-tank, l4,as describedwiliserveto oft-heflberbysubstantialiy thewhole-mass of waterinthetankratherthan byanylocalized softens the gum and reslnom material rendering it relatively plastic. If the process is continuous the water in the tank or vat, i4, maybe changed tank, into a short open com t, 21, having,

'an outlet, II, which may lead into the sewer or to any suitable receptacle if it is desired to recover the dissolved matter from the water. A drain plug, 29, may also be provided near the bottom of the partition wall, 20, for use in occasionally flushing out the entire tank, i4,'at which times any resinous matter which has settled in the tank may be collected and removed.

The fiber will not be injured by treatment with the hot water for a longer period than thirtyfive minutes. Therefore the initial portion of the fiber maybe allowed to lie in the troughs, 2|, this length of time and then may be started through the feed rolls, ll. These rolls are held toward each other under adjustable spring pressure as indicated in Figure 2 and to accommodate the sliver. form in which the fiber is being handled, it may be preferable to provide one of with circumferential grooves, ll,

Droviding space for the thicker portions of the silver so that substantially equal pressure may be exerted by each of the rolls upon all the fibers of each sliver. This pressure serves .to squeeze oil. fromthe fiber the major portion of the gum which hasbeen softened and loosened by the hot water treatment in the vat, l4, and this gummy material with the water which is also pressed out by the rolls, ii, is discharged into a special accumulating trough, il and thence through any suitable conduit, 2|, may be carll, inwardly from ing end of the silver a1so,ee1 'ried-off for reclamation in accordance with well understood methods. In the process of squeezing the hot-watersaturated sliver between the spring-pressed rolls, the rolls are exposed to the hot'water by their contact with the silver.

Whatever length of silver it is possible to make from the initial quantity of fiber in the" receptacle, it, itwill be understood that the silver may be rendered continuous by splicing onto it from time to time additional units of fiber as delivered from the picker, 8, and before the trailhas entered the trough of thetank, II. It should also be understood that in the structure as illustrated with multiple troughs, 2|, started simultaneously and will continue to travel parallel to each, other through the appsratus. The fiber continues its movement through the rolls, l5, and enters the second set of troughs. 30, in a tank, 3|, structurally similar to the troughs, 2i, and their tank, It. The bath in the tank, 3|, however, is a weak solution of sodium carbonate, preferably about'three percent, and for this reason the exposed metal of this structure should be of copper or heavily nickled to prevent corrosion and to prevent discoloration of the fiber which might occur if ordinary iron piping and tanks were used. The fiber travels through the troughs. S0. at the same rate as it moved through the troughs, 2|. As a matter of convenience, if each set of troughs is made about thirty-five feet longthe fiber will be moved through them at the rate of one foot per minute. And to avoid cooling and hardening of the gum during the transfer of the fiber from the tank H to tank 3|, it may be subjected to hot water sprays at i5, and is adjacent the squeezing rolls, I5, as shown in Figure 2.

The function of the alkaline bath of sodium carbonate is to remove any remaining gum from the fiber by dissolving it, thus freeing any associated resin from' the fiber and permitting it to fall to the bottom of the vat from which it may be collected at intervals for reclamation in mercharitable form. A small quantity of the alkaline solution may be added from time to time to compensate for evaporation and for that which is carried off with the gum and resin-removed in the vat, it. At the end of the tanlr, 36, the fiber again passes through squeezing rolls shown at M which remove most of the alkaline solution from it. These rolls may be mounted directly in the end of the vat, ti, or, as shown, may be separated from it and provided with a collecting trough, 33, for the solution squeezed from the fiber. Asthe fiber approaches the rolls it may be further clarified by a rinsing spray of clear water indicated at M.

For certain paper, it is desirable that even the small quantity of alkali remaining in the fiber be neutralized, and for this purpose it may be passed from the rolls, it, directly into a neutralizing bath of wealr acid indicated at so. Brief dipping in this bath is all that is necessary, therefore the tank, 35, may be of much less length than the preceding tanks employed in the process and from it the fiber may be passed through wringing rolls, 36, and then through a rinsing bath of clear water, ii, to final squeezing rolls. it, which will press most of the moisture from the fiber. Emerging fromthe rolls, 38, it proceeds across any suitable feed table or support, 3!, to a dryer which is indicated diagrammatically in Figure 3 as a a plurality of these slivers will be these troughs and tanks being uses such as the manufacture of continuous belt conveyor, ll, which may be understood as of any suitable reticulated form, as

for example, a series of belts or ribbons with transverse supporting bars secured to them at intervals. Associated with the dryer belt, 40, are suitable heating means such as steam pipes, ll, and a blower, 42, for supplying air through a distributing conduit, 43, with ports, 44, through which the air passes for heating contact with the pipes, GI, and thence through the conveyor belt, "I. for drying the fiber. 'At the discharge end of the belt, 40, the fiber is preferably passed through a series of fiuted rolls, l5, which may be similar to the rolls, 3, 4, i, S, employed at the beginning of the process except that they need not have corrugations of graduated dimensions, as in the other series, but may be all substantially alike; the function of these rolls, 4!, is simply to mildly fiex the fiber atthe completion of the drying to soften it and loosen from it any film of foreign material which may have adhered through the various washings and rinsings; and may have been dried onto the surface in the final step of the process.

As it emerges from the softening rolls, 45, the fiber may be further treated by combing or card-' ing devices of any suitable design, as may be readily understood by those skilled in the art.

spinning, it may be desirable to' subject the fiber to final chemical bleach, but this can be extremely mild by reason of the fact that the material has already been so thoroughly cleansed and washed in the process herein described. As a result, the spinning fiber will be much stronger than that which has been subjected to a relatively severe bleaching, as such process always acts to weaken the cellular structure and therefore tends to weaken the strength of the fiber. Fiber produced in accordance with my process having been degummed almost entirely by mechanical means which at the same time is designed to handle the fiber always gently throughout the process, will be found to present a softness of texture and a. luster almost rivaling a silk fiber, and since it has been thoroughly washed and cleared, it will take a fast dye rendering it suitable for spinning and manuiiacture into cloth for a wide range of purposes for which linen has not heretofore been thought suitable.

in theapparatus shown, as indicated in Figures 2 and b, I have included vapor hoods, t l extending slightly above the side lls, ill, of the tanks and communicating with the suction passages, it", so as to draw ch a and other vapors tending to rise from the surface of the liquids in the tahknthus facilitating handling of the material if necessary by workmen and keeping the premises clear of unpleasant steam and odors. Another feature of construction of the apparatus which is quite important is the provision of oiled pressure pads of absorbent material such as felt or the like shown at 90 in contact with u per and lower rolls of each pair of squeezing rolls for the purpose of cleaning the rolls of any adhering particles or fiber which would otherwise cling to their associtact with the surfaces of hesion of the material and will also act as scrapers to remove fiber which might otherwise be carried around the rolls.

Although I have shown and described herein a specific group of mechanisms and apparatus for ing from the spirit and scope of the invention.

I claim:

1. A process for the purpose indicated which includes forming the fibrous material into a sliver after the shive has been removed therefrom and feeding it slowly through a heated water bath to soften the gum and resin and dissolve out the water-soluble material, passing the silver between rolls for removing the softened gum and resin and protecting the sliver against atmospheric cooling by spraying it with hot water in its passage to and through the rolls.

2. A process for the purpose indicated which includes loosening the shive or woody material mm the fiber in its dry state and separating a substantial portion of the said material therefrom, then submerging the fiber i'or soaking it in liquid maintained at a temperature suitable for.

and directing a softening the gum and resin, liquid current maintained at said temperature into impact with the sliver while the latter is free from mechanical pressure and without substantial time interval between the submergenee of the fiber for soaking it and its exposure to the impact of the liquid current; whereby the gum is main tained in said softened condition throughout the step of separation by liquid current impact.

3. A process for the purpose indicated which includes forming the fibrous material into a sliver after the shive has been removed therefrom, feeding the sliver slowly through" a bath of water maintained at a temperature suitable for softening the gum, exposing the sliver to the directimpact of a current of water maintained at said temperature without substantial intermission in the exposure to liquid maintained 'at said gumsoftening temperature and while exposed to said liquid current impact, passing the sliver between squeezing rolls the surfaces of which make conthe sliver for squeezing, the surfaces of the rolls being thus exposed to said liquid.

4. A continuous process for the purpose indicated which consists in feeding dry stalks or straw through instrumentalities adapted to apply pressure and limited fiexure thereto forloosening the shive or woody material, and-then continuing the movement through a picker arranged for combing out and removing most of said woody material, forming into a sliver the fibrous portion of the straw emerging from the picker and feeding said sliver longitudinally at a relatively slow rate through a liquid bath maintained at temperature suitable for softening the gum, then without intermission in the exposure of the silver to the liquid maintained at said gum-softening temperature, passing the sliver between squeezing rolls in direct contact of the fiber with the surface of the rolls on opposite sides of the sliver while maintaining the sliver in exposure to the liquid maintained at said gum-softening temperature, splicing additional fibrous material from the picker to the sliver at intervals toextend the length indefinitely, feeding the silver after passing the rolls into a mild chemical water bath through which it moves longitudinally at the same rate of speed to permit the remaining gum to be dissolved and the associated resinto be freed from the fiber, then feeding the fiber through additional pressure means, rinsing and drying it, and finally subjecting said fiber to mechanical fiexure for softeningit, and to combing or carding means for removing any adhering particles and straightening the fiber. I 5. A process for the purpose indicated which includes forming the fibrous material into a sliver after the shive has been removed therefrom and ,feeding it slowly through a heated water bath to soften the gum and resin and dissolve out, the

water soluble material, feeding the sliver out of said bath and then passing it between rolls for dislodglng the gum and resin while applying heat to protect the sliver against atmospheric cooling during its passage to and through the rolls.

6. A process for the purpose indicated which includes forming the fibrous material into a silver afterthe shive has been removed therefrom and feeding it slowly through a heated water bath to soften the gum and resin and dissolve out the water soluble material, feeding the sliver out of said bath, then subjecting it to mechanical pressure to dislodge the gum and resin and applying heat to the sliver immediately upon its emergence from the heated water bath to prevent cooling and hardening of the gum before its dislodgement.

7. A process for the purpose indicated which includes forming the fibrous, material into a sliver after the shive has been removed therefrom, subjecting the fiber to .a heated liquid bath to dis-' solve out the coloring matter and soften the gum and resin, then separately dislodglng and collecting the softened gum and resin outside said liquid bath while applying heat to prevent cooling and hardening of the gum and resin.

ROBERT FURSYTH.

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