US2551128A - Decorticating process - Google Patents

Description

y 1951 T. A. HULFISH ET AL 2,551,128

DECORTICATING PROCESS Fild July 9, 1945 2 sheets-sheet 1 3 I INVENTOR.

THOMAS A. HULFISH, AND

w|| 1s s. w DO THEIR AT RNEY May 1, 1951 T. A. HULFISH ET AL DECORTICATING PROCESS 2 Sheets-Sheet 2 Filed July 9, 1945 INVENTOR. THOMAS-A HULFISH, AND v WILLIS G. WALDO BY QLfl, 6 .7

THEIR ORNEY fatenteci May 1, 195i cumin P'ATENT Titties A fifitms ,;ii na av;e, andwillis Waldo, Washington, 'D. 0., said Hulfish as- Signor t "said wane Applicati 6 crates.

r mc td iii h g i t fimei m tim substantial absence of any requirementfor nicety,

of adju'stnientofthe apparatus in the-ape paratus is simple, compact and relatively inex pensive, involving a minimum numb-er. of moving parts; is rugged, reliable and requires minimum servicing; which isof long use'ful l'iie witl'i high unit capacity while operatin' 'g at ,low rotat '1 speeds; in which all waste material is th'orou if and. rapidly removed without ,tangiling orlb .-l ing of the strands of the b'alst fibers; and in w ich the decorti'cating action can be readily {and I siti'vely varied, during the cqurse, dfthe scutchmg" operation, at the will offthe operator;

Other objects inpart \wilLbe ,obvio the following description, taken in the night (if the accompanying drawing.

Our invention accordingly residesin theseve l;

arrangements of parts, combinations of elem s and features of construction,inthe several' ational steps, and. as Well, in the combinatlo 1 each" of the same with one or more" df the othersl the scope of the application of all of is more fully set forth in the claims at the end of this specification. I

In the dravv1ng,.where1n we d sclose one embodiinent which we prefer at present,

Figure 1 is a simplified perspective View of machine according to our invention, certain parts being omitted for clarity; while Figure 2 is a transverse sectional viewof t he" machine.

Like reference characters denote like parts in the two views. I u j, A s conducive to a more thorough understa in' of th pur e e t t ar $9 2116 939 it. vention, it may be noted that many plants, we ds,

and the like are egteriofly sheathedby hat b li gen r l w ba j-@., .1 i general character, this she'a'thin'g" co pr a ief part pointedouthereinafterduring thee ,urseoi, u 7 u H for*subsequentprocessing; The-sheared-tops m ee ave lbefinuresorted to, rigidly supported to, i and past a. fiXd back.

an r51; 5', 1945, that eii'ilist (o1. iii-'7) cells, known as basttfibers or 'bast cells. These iibershave been foundto be highly desirable in themanufacture ofi'nany fabricatedarticles, fs'uc'h asrcpe and the like. As illustrative of thefoie going ramie maybe cited as a vegetable product incliiding bast fibers, which, upon extensive tests, are io'und to. displayv enormous tensile ,strength; In fact, fibers obtained from-the bark of this V Chinese weed have aten'sile strength closely cor Rgar'nie, in, its matured stalksgaverages about feet,i1 1 heig'ht and possesses vanstalk some feetlin length, theremaining lengthwbmi prising" the flowering top.- A typical stalk h hollow stem with a pithy interior" end ar t skinned outershell. customarily, theraniie'stalk s. .Qu lw t lah 'rve e wh reu n t 'i l e are gathered together andi'tied into bundles; as. by means of a reaper or binder. *The'flower ing tops are cut from these bundles; leaving only thestalks either may be discarded or employed as food for livestockw v 1 time cut stalks are -now-ready=for -rernoval of thelenveloping waste/materialtfrom-abouttheibast Q fibers.1;;These lattersar'eembedded,near the pe-' V the fibers-i are beaten from thestalh has heretofoiie normally been employed iorthis-purpose tc H'eret'ofore machine's. generally similar in a l pearance, to our new machineldisclosed .lir'i thi applicatiqh have. been employed to remove the; outer skin or waste materialt coinprising' part v,of

the stalks from aboutthe fibers, it is, however,-

& sig ificant req me t o known priorarttqhi niqu-ethat" these outer-skin's have been rerjio d through a cutting, shearing and' scraping ac'tio H Tcinsure proper shearing operation, steel cutting} n mW b HEM iY' supp or,v anvil; sometimes :called ,a back plate}; o th, proper cuttingia t qm se f ctu edwthelinvolveacritical distance'of several thou'sia'ridth's" of an inch. Either over-spacing or under-spacing beyond the limits of this critical zone is found to result in failure of cutting operation or in jamming of the machine. Particularly has the critical nature of this spacing demonstrated itself in the processing of bast fibers from abaca and other hard-fibered plants. Even then, the primary problem being to out 01f the tough, fibercontaining skin, recourse to a subsequent scraping action has been found to be desirable.

The close spacing of the cooperating cutting elements required to effectuate proper cutting action requires disposing the cooperating cutting elements so that the distance therebetween is substantially less than the known diameter of the stalks undergoing treatment. A crushing action between non-yielding bearing surfaces is exerted upon the stalks during their passage through the machine. As a result, and particularly as an incident to cutting hard fibers such as abaca or hemp, this crushing action causes the fibers to whip up near their ends and to become snarled. It is of course highly desirable to maintain the individual fibers of the greatest possible length, so that the finished product incorporating such fibers will display the highest possible tensile strength. To achieve this maximum fiber length, it is manifestly important to remove such possibility of whip-up and snarling insofar as this can be done.

Not only in these prior art processes and machines is cutting of the fibers resorted to, in order to remove them from the stalk, but as well there is tearing resulting from the inflexible positioning of the movable cutting blades relative to the fixed back plate. This cutting arbitrarily limits the maximum fiber length, while the tearing exerts further weakening action. Moreover, this nice adjustment between the cooperating elements of the prior art machines involves a critical clearance angle, so that expert supervision is required at all times, together with the attendance of skilled attendants. Appreciable expense in operation has been accepted as a necessary evil.

From the foregoing it will readily be understood that nicety and criticalness of adjustment of the decorticating machines of the prior art constitutes a paramount consideration at all times. Satisfactory results can be achieved only when the machines are maintained at highest operating efiiciencies, and while operating under skilled and highly trained maintenance and supervision. Both first costs and operating expenses are necessarily high. Any appreciable variation either in kind of stalks undergoing processing, or in average diameter of stalks within the particular class of plants being treated will necessitate temporary shut-down of the machine and adjustment of the blades thereof. Setting of the cutting blades during the operation of the process is impossible, either for varying the decorticating action or for any other purpose.

Moreover, decortication machines as heretofore known and available are comparatively small and of limited capacity. Because of the fine adjustment required the blades are necessarily short. Moreover, the machines have required the use of auxiliary decorticating means comprising a plurality of fine-diameter water jets operating under high pressure, participating in the decorticating action. High rotational speeds are required, effectively contributing to the undesirable phenomena so frequently observed of 4 whipping into tangles with subsequent breakage of fibers.

An important objective of our invention therefore is to avoid in large measure the disadvantages and difiiculties attendant upon the employment of the techniques and machines heretofore available, and in so doing, to provide both a simplified method of decorticating bast fibers, and a simplified machine, for carrying that method into execution, capable of high-capacity operation with relatively slow rotational speeds, in which whippage, tangling, snarling and breakage of the fibers is substantially eliminated, in which mild softening, compressing and pushing action is exerted longitudinally of the fibers over a comparatively extended interval of time, and in which rapid and complete decortication is achieved, with large quantity output, sensitive adjustment of the decorticating action being readily feasible during operation of the machine to accommodate for various types and sizes of fibers, stalks and the like.

Essentially, the method of decorticating in accordance with our invention comprises flexibly wiping the fiber strands longitudinally of their lengths at a slow rate of speed whereby the fibers are freed from the pectins of the stalks and other waste material in which they are embedded with a minimum of wiping, tangling and breaking. All cutting and shearing is avoided. No decorticating, high-pressure water jet is relied upon. Inasmuch as the individual stalks are fed transversely of the direction of wiping, likewise at a slow rate of speed, so that fresh stalks may be continuously introduced into the zone of operation, the process is a continuous one. The method therefore is adapted to quantity treatment.

More particularly, in a typical instance according to the practice of our invention the stalks are first prepared by passing them through smooth squeeze rolls Where just enough pressure is applied to crush them, fiatten them out and crush the pithy interior, for ready removal of the latter. The shape, surface and contour of the rolls, and the degree of pressure, are so determined that the fibers of the stalks are not affected by this preliminary crushing treatment. In part, this protection of the fibers may be attributed to the absence of cutting, breaking, or snarling. Long, uninjured and strong fibers result. Moreover, the squeezing and flattening operation provides a broad contact surface of the stalks for facilitating subsequent removal of waste material from about the surface-embedded fibers through the gentle Wiping operation which characterizes our invention.

Following the preliminary crushing operation, low-pressure hot Water preferably is applied to the crushed stalks for softening the fibers, the surrounding pectins in which the fibers are embedded, and the pithy material comprising the rest of the stalk. This softening permits the removal, in the subsequent Wiping operation, of the surrounding and undesired green material, pectins, etc., leaving as a remainder the desired fibrous material which is firmly gripped during the wiping operation.

We then subject the fibrous material, throughout the wiping operation, to a slow-speed, mild, softening, compressing and pushing operation for a duration of approximately ten seconds. As desired, and during the latter portion of the wiping operation, the pressure with which the wiping is carried out, through the use of flexible wiping blades for exampla can be increased-at the will of the operator, to insure that the fibers are entirely cleansed of their surrounding debris.

Practice of our new method as set forth in the A foregoing can of course be carried-into execution through the use of a number of different forms of apparatus. We have, however, evolved a machine which is particularly suitable for eifectuating our new method at maximum efficiency. The salient details of this machine are clearly disclosed in Figures 1 and 2 of the accompanying drawing to which attention is now invited.

Accordingly, having reference more particularlyto the drawing, we provide upper and lower endless gripping chains Ill and It, constructed of any suitable material. In one instance we construct these chains of metal, with exposed links. To protect the fiber stalks, however, which are inserted transversely between said chains,.we prefer to form the links of the chain of rubber elements or else to face them with rubber, much in the manner of the conventional Caterpillar tractor tread. The upper grip chain is sprocket-fed or otherwise energized for continuous travel between sprockets or like powering means [2, l2 disposed one at each end of the machine undergoing discussion (Figure 2). With this disposition of the sprockets, it will be seen that the chain travelscontinuously along the length of the machine. The sprockets 12 or like means may be powered in any suitable and conventional manner (not disclosed).

The sprockets l2 are carried by suitable hangers or brackets l 3, l3 flanged at their upper surfaces M, M, for mounting on the frame of the machine or other suitable supports. Hangers l3, lit-terminate at their lower end in a yoke por- ,tion [5. This yoke carries in its arm portions l5, ii a thrust plate it, against which thrusts a coiled spring or the like l1. Between the free end of this spring ll and the sprocket I2 is pro vided a follower or bearing plate l8 which bears against the sprocket i2 and resiliently and yieldably thrusts the same against the stalks disposed between it and the lower sprocket member, shortly to be described.

Similarly, the continuous lower grip chain II is mounted on and carried by and between cooperating sprockets or similar impelling means I9, I9. Just as in the case of chain it, chain It is constructed of any suitable material, such as steel or the like, but in the preferred instance,

I is formed with'a rubber bearing surface so as to protect the fibers against injury as they are carried between the two chains. Sprockets I9, is are powered in any suitable manner, from conventional means, not illustrated. These sprockets likewise are disposed one near each end of the machine and are carried in pedestal supports 20 which terminate at their upper ends in yoke 2 i, in which the sprockets l9, 59 are mounted.

Chains Ill and l i are parallel to each other and are superposed one on top of each other. They are powered to drive in the same effective direction along the length of the machine. The lower surface of the top chain IE3 and the top surface of the lower chain H are disposed contiguous to each other so as to provide between them a gripping surface which is continuously moving along the length of the machine.

A back plate 22, in the preferred instance formed of steel, but which may be of any other suitable metal or other material sufficiently rugged in character, extends the length :of the machine. Advantageously, and in a typical in- 6. stance, this back plate 22 is approximately 10 feet in length. This back plate 22 isconcave in section, its curve beingstruck on a radius of substantial length: The upper lip of this back plate terminates at the junction defined by the two travelling chains,- while the lower-end thereof terminates just short of the foundation on which the pedestal 20 is carried.

Inpractice, according to the technique of our invention,- and to carry into effect the method hereinbefore set forth, we drape the stalks of ramie, abaca, hemp, or other suitable hard-'- fibered stalks, the fibers of which possess the desired tensile strength, between the grip chains It and l l at the forwardend of the machine, as- Suming that the effective direction of travel of the chains is from the left to the right as seen in Figure 1. These stalks havebeen previously crushed'as between smooth rollers, so as to flatten them, to crush the pithy core therein, and to increase the'surface area which will be subjected to wiping action. Following this preliminary processing the stalks are disposed in their crushed, flattened state on the back plate 22 in' the mode most advantageous for the removal of the undesired waste and pithy material, pectins and the like. The stalks 23 are fed into the field between the chains I6 and II at the left end of the machine, and in so doing, are draped with their lengths extending across the concave width of the back plate 22. Of course, if desired the direction of processing can be reversed. By means of the travelling chains l0 and II the stalks are thereupon carried slowly and at uniform feed to the right in Figure 1 along the length of the back plate 22; In a typical instance a rate of travel of about one foot per second has been found to be quite satisfactory.

To insure preliminary softening of the stalk material in which the fibers are embedded, they are subjected to a sprinkling action throughout their travelwith hot water at low pressure from pip'e 3| extending the length of the machine. This hot water spray softens the waste material and permits it to be wiped from the fibers during the wiping'operation.

A circular drum cooperates with the back plate 22 and in the preferred embodiment is substantially but adjustably coaxial therewith. This drum extends the entire length of the machine. Since it is coextensive with back plate 22, then in a typical instance it is about ten feet long. We find a satisfactory rotational speed to be revolutions per minute. The drum 2c: is carried in a pedestal 25 on which suitable pillow block bearings 23 are provided. Shaft 28 of the drum 2 is rotatable in these bearings. A series of arms 21 radiates with equal angular spacing from the central spider 25 of the drum 24, the focus of which spider is comprised by shaft 28. These arms, in the preferred instance are comprised of steel, and serve to carry flexible wiper blades. The flexible wipers 3E] comprised of rubber or similar products possessing the required qualities of flexibility, are carried at the free ends of the arms 2?. As the drum 24 rotates these flexible blades 33 bear yieldingly, but with substantial pressure, against the fiber stalks 23. A longitudinally-applied wiping action is exerted against these stalks throughout their lengths.

The blades 30 extend the entire length of the machine. We find it desirable in some instances todivide the drum into a plurality of sections longitudinally along its length, and to stagger the blades 30 of each section relative to those of the other sections. These blades exert their wiping action longitudinally of the stalks throughout the travel of these latter through the machine, at right angles to their lengths.

In the practice of our invention, the gentle, slow-speed, wiping action had is not accompanied by any shearing, scraping, or cutting. No difficulty is encountered in postioning the back plate 22 and the blades 30 relative to each other. No critical spacing is involved, inasmuch as no shearing or cutting action is required or desired. It is sufiicient that the spacing be such that the flexible blades 30 bear against the back plate 22. Moreover, it is entirely feasible, in order to increase the cleansing action, to incline the axis of either the back plate 22 or the drum 24 relative to each other in the direction to the delivery end of the machine, to increase the decorating action as the treatment progresses. Throughout the practice of our invention the fibers are left intact and unharmed. Very little whipping, snarling, tangling or breaking of the fibers occurs, due in large measure to the slow speed at which the operation is carried out.

When the preliminary crushing of the stalks is properly carried into effect, together with subsequent washing in hot water, thorough cleaning of the fibers and separation thereof from their encompassing material is effectively accomplished. The practice of our new method achieves a resultant product which is superior in every way to the fibers heretofore obtained according to known techniques.

Thus it will be seen that We have provided a method and apparatus by which there is ac complished the many objects hereinbefore set forth together with numerous real and practical advantages. Our machine is essentially simple in construction. It involves a small number of moving parts, and these comparatively inexpensive in themselves. No criticality of adjustment of the several parts relative to each other is involved. It is sufficient as has been disclosed, that the wiper blades 30 be in contact with the back plate 22. Because of the flexible nature of these blades considerable latitude is permissible as to their positioning. The resilient fol lower blade I8 insures that the gripping chains Ill and H are pressed closely against each other. Thus the stalks are at all times securely gripped against the most vigorous wiping action. Moreover, increased decorticating action, along the length of the machine, is had where the axes of the back plate and the drum are disposed at an. angle to each other. Absence of cutting, shearing, or scraping insures that long fibers are obtained. The gentle, slow-speed action effectively avoids the detrimental whipping, tangling and breaking which has so frequently character ized the heretofore known techniques. The long fibers which we obtain therefore are substantially undamaged, and retain their full tensile strength.

Substantially the only attendance which is required is in connection with supply of the stalks to the machine. Thus, labor requirements are reduced to a minimum. The slow-speed operation of the machine minimizes Wear. This contrasts strikingly with the rapid wear of known machines attendant upon the high rotational speeds required for satisfactory cutting action. The length of the machine, insuring that a large number of stalks are undergoing treatment,

8 simultaneously insures high unit output. All these and many other highly practical results are obtained according to the practice of our invention.

Inasmuch as many embodiments of our method and apparatus will readily occur to those skilled in the art, once the broad aspects of our inven' tion are disclosed, and since many modifications will suggest themselves of the embodiment herein set forth, we intend that the foregoing disclosure be construed, not by way of limitation,

but simply as illustrative.

We claim as our invention:

1. In a method of decorticating fresh stalks having a bast portion with fibers therein, the art which comprises transversely passing said stalks continuously and rigidly across a bearing surface, and continuously wiping said stalks longitudinally of their lengths with a firm but yieldable pressure during said transverse passage, whereby the waste products of the stalks are wiped off and removed.

2. In a method of decorticating fresh stalks having a bast portion with fibers therein, the art which comprises the steps of disposing the stalks on a bearing surface in a thin sheet with their strands extending in the same direction, and continuously wiping said stalks in the direction of their lengths with a firm but yieldable pressure, whereby the Waste products of the stalks are wiped off and removed.

3. In a method of decorticating fresh bast fiber stalks, the art which comprises the steps of disposing the stalks in a thin sheet with their strands extending in the same direction, continuously and rigidly passing the stalks along a bearing surface transversely of their lengths and at a rate on the order of one foot per second, and simultaneously therewith continuously wiping the fibers longitudinally of their strands with a firm but yieldable pressure, thereby to wipe off and remove the waste material of the stalks.

l. In a method of decorticating fresh bast fiber stalks, the art which comprises disposing the stalks in a thin line on a bearing surface with their strands extending in the same direction, softening the fiber stalks in water, moving said stalks continuously and rigidly along said bearing surface transversely of their lengths, and simultaneously with this movement continuously wiping said fibers in the direction of their lengths With a firm but yieldable pressure to wipe off and remove waste material therefrom.

5. The method of decorticating fresh bast fiber stalks comprising, in combination, the steps of disposing the stalks in a thin line along a support with their strands extending in the same direction, washing the stalks with a low pressure stream of hot water, moving said stalks trans versely of their lengths continuously and rigidly across a bearing surface, and simultaneously therewith continuously Wiping said fibers in the direction of their lengths for some ten seconds with a firm but yieldable pressure to wipe oif and remove waste material therefrom.

6. The method of decorticating fresh bast fiber stalks comprising first crushing the fiber stalks to an extent sufficient to crush the pithy interiors and to flatten the stalks without fiber injury, softening the stalks with hot water, disposing the stalks in a thin line along a bearing surface with their strands extending in the same direction, continuously and rigidly moving said stalks along said bearing surface transversely of their lengths with a firm but yieldable force,

thereby to wipe off and remove the waste material of the stalks.

THOMAS A. HULFISH. WILLIS G. WALDO.

REFERENCES CITED Th 'e fo llowing references are of record in the file 'of this patent:

UNITED STATES PATENTS Number Name Date 657,023 Dear Aug. 28, 1900 1,200,615 Hubler Oct. 10, 1916 Number Number

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