US 3341008 A
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p 1967 M. MAYER, JR.. ETAL 3,341,008
FIBER FRACTIONATING APPARATUS 3 Sheets-Sheet 1 Filed June 12, 1964 SUCTION MEANS SUCTION MEANS FIG.|
INVENTORS MAYER MAYERQJR' HEBERW.WELLER,JR.
ATTORNEY P 1967 M. MAYER, JR.. ETAL 3,341,008
FI BER FRACTIONA'I ING APPARATUS Filed June 12, 1964 5 Sheets-Sheet 2 DRIVE MEANS FIG. 2
INVENTORS MAYER MAYER,JR. HEBER w. WELLER,JR.
. ATTORNEY p 12,1967 M. MAYER, JR., ETAL' 3,341,008
FIBER FRACTIONATING APPARATUS Filed June 12, 1964 3 Sheets-Sheet 5 SUCTION MEANS SUCTION MEANS SucnoN MEANS r SUCTION MEANS INVENTORS MAYER MAYER JR. HEBER w. WELLER,JR.
ATTORNEY United States Patent Ofiice 3,341,008 Patented Sept. 12, 1967 3,341,008 FIBER FRACTIONATIN G APPARATUS Mayer Mayer, Jr., New Orleans, and Heber W. Weller,
A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United State Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.
This invention relates to an apparatus for fractionating fibers into length groups. More specifically, it relates to an apparatus for electrostatically aligning fibers and subsequently separating the aligned fibers into fractions having specific lengths.
Still more specifically, it relates to an apparatus for removing short fibers from cotton lint. Another object of our invention is to provide a novel process for determining fiber-length distribution.
As used herein, the term fibers relates to the individual components of cellulosic or noncellulosic materials such as cotton, rayon staple, nylon staple, vinyl staple, and the like. Because of its wide use, cotton will frequently be referred to below as the fiber, but it is to be understood that this usage is illustrative only.
The term lint as used herein, relates to the full-length fiber, sometimes referred to below as staple. The term short fibers relates to the shorter portions of the lint or staple, usually portions of fibers not longer than about threeeighths inch.
The presence of these short fibers has several disadvantages in the processing of lint cotton int-o yarn and/or fabric. In the first lace, short fibers reduce the strength of the yarn. This results in a greater number of ends down or breakage during spinning thereby decreasing the efficiency of the process and increasing the cost. In the second place, these shorter fibers increase the total number of ends of fibers per unit length of the resulting yarn. These ends tend to protrude and impart a .fuzzy character detrimental to the quality of the yarn. In the third place, yarns produced without these shorter fibers are characterized by their increased strength, their fineness, their evenness, their smoothness, their uniformity, and their commercial desirability.
In the past, these short fibers have been removed only by a low-capacity, costly, combining process. Because of the great expense involved generally, only fibers having a classers staple length of at least about 1 A,; inch, the more expensive of the cotton fibers, have been subjected to the combing operation. Therefore, it will be seen that prior to this invention there still remained a need for a practical means of eliminating the shorter fibers'from lint. Such a means should be economically adaptable to the removal from lint of short fibers having a length of not more than /8 inch. Last, but not least important, the means should not break or otherwise physically damage the fibers.
The apparatus which is the subject of our invention comprises any suitable means for uniformly introducing loose masses of relatively untangled partially individualized fibers into a fractionating chamber comprising an outer incurvate conductive electrode and a rotating, in-
ner cylindrical electrode between which the fibers are further individualized and aligned. Both electrodes are electrically charged. Hence the fibers are rotatably conveyed to any appropriate doffing mean such as one or more suitably surfaced rolls spaced from the charged cylinder a predetermined distance necessary for removing fibers of a length longer than that distance. For fractionating fibers into two length-groups; i.e., one with fibers longer than a predetermined length, e.g., about /8 inch, and one with fibers shorter than that length, only one dofiing roll is required. When n fractions of fibers are desired, n-l additional doffing rolls are needed. Said roll or rolls, are spaced a distance equal to, or slightly less than, some predetermined fiber length. The longer fibers are removed by the specially surfaced dofling roll, from which doffing roll they may be removed for further processing by any suitable means, such as suction air. The short fraction of fibers which remains on the charged roll can be removed later for subsequent processing, or disposal, by suitable means, such as suction air.
One, but not necessarily the only, embodiment of an apparatus suitable for the practice of of this invention is described in the accompanying drawings in which:
FIGURE 1 is a sectional view showing the essential features of the invention.
FIGURE 2 is a sectional view showing details of the charged roll assembly.
FIGURE 3 is a sectional view showing details of another embodiment of this invention.
FIGURE 4 is a sectional view, similar to FIGURE 2, showing details of a modification of the charged roll assembly described below.
Referring to FIGURE 1, loose masses of disoriented fibers 11 are supplied by any suitable means, although positive air is preferred, through duct 12 into chamber 28. This chamber is bounded on one side by the rotating, charged-roll assembly 13 and on another side by electrode 14, the incurvate portion of duct 12. When an electric current is passed between these electrodes, an electrostatic field is produced in chamber 28. Charged roll assembly 13 (FIGURE 2) comprises outer cylinder 15,
spacer ring 16, and electrode 17. Cylinder 15 may be constructed of any conductive or nonconductive material. However, for reasons of convenience and efficiency, we prefer to use a nonconductive material, such as polyvinyl chloride, nylon, Bakelite, Pyrex glass, and the like. Electrode 17 is a conductive material secured to shaft 101 within and concentric with cylinder 15. If a conductive outer cylinder is preferred, construction may be modified to utilize a simple conductive cylinder 17 in substitution for assembly 13, thus making 15 and 16 unnecessary. Electrode 17 may be any desired distance from cylinder 15, or it may be in intimate contact. This modification is shown in FIGURE 4, wherein the nonconductive cylinder, designated 15a, is in intimate contact with electrode 17. We prefer to space cylinder 15 from electrode 17 by an insulator ring 16, although satisfactory results are obtained when electrode 17 (e.g., tinplate) is fitted snugly against the inner surface of outer cylinder 15.
As noted above, electrode 14, FIGURE 1, is incurvate relative to charged roll assembly 13. The distance between the electrodes is at a maximum in the region where the fibers first enter the electrostatic field and uniformly decreases as the electrode approaches dofier 22. As a result, the potential gradient of the electrostatic field is at a minimum when the fibers first enter chamber 28 and increases to a maximum at about 29.
Electrode 17 is energized through conductor 18, which is connected to the electrode through slide wire contact 19 on shaft 101, and electrode 14 is energized through conductor 20. An electrostatic field is produced between electrodes 14 and 17 using alternating current or preferably a direct current produced by any means common to the art. Although the successful operation of this invention is not so limited, we prefer to have electrode 14 connected to ground.
Fibers fed into duct 12 by any suitable external means at a uniform rate, such as positive air or feed roller (not shown) are conveyed into the chamber and into the region of electrostatic field in chamber 28 produced by charged roll assembly 13 and electrode 14. The effect of this field is to cause the fibers to become aligned parallel to the lines of force between electrodes 14 and 17. Charged roll assembly 13 is rotatably mounted in conventional bearings and driven in any conventional manner, such as a motor, pulleys, chain, belt, etc. These conventional means are shown schematically in FIGURES 2 and 4 by a box designated DRIVE MEANS. As a result of the incurvate contour of the electrode 14 with reference to charged roll assembly 13, a uniformly increasing electrostatic field gradient is produced in the direction of rotation of assembly 13. The increasing field gradient causes the aligned fibers to migrate to the Zone of higher field gradient 29.
The radially aligned fibers 21 are carried on cylinder to a suitable dofling means, such as a toothed dofier roll 22, secured to shaft 102. As can readily be seen from FIGURE 1, dofier 22 is enclosed in a housing 103 which is an extension of electrode 14. Doffer roll 22 may be surfaced with any desired covering besides the toothed surfaces; i.e., the covering may be a velvet cloth, walrus hide, card clothing, or a pressure sensitive adhesive. Doffer 22 is rotatably mounted in bearings (not shown) and is driven by any conventional means shown schematically in FIGURE 1 by a broken line box designated DRIVE MEANS. Doffer 22 is spaced from cylinder 15 by a distance sufiicient to remove all fibers longer than a predetermined length while permitting all fibers shorter than the predetermined length to remain on cylinder 15. The fraction of longer fibers removed by doffer 22 is removed for subsequent processing, by any means common to the are such as suction air through duct 23 induced through opening 24. This conventional means is shown schematically in FIGURE 1 by a box designated SUCTION MEANS, connected to duct 23. Doifer roll 22 also may be rotatably mounted in readily removable bearings (not shown) so that it may be easily removed and weighed before and after operation to determine the weight of the fibers in the length group which is removed.
The shorter fraction of fibers 25, FIGURE 1, remaining on rotating cylinder 15 is then removed through duct 26 by a second suitable doffing means such as suction air induced through opening 27.
As noted above, FIGURE 3 is a schematic view of another embodiment of our invention. In this embodiment, there is shown a modified arrangement which is similar in operation to the referred embodiment discussed above. For this purpose, incurvate electrode 14 is modified to provide an incurvate electrode 104 having a plurality of extensions, such as housings 1115, 105, 107, 108, 109, and 110, to provide for doffer dolls 30, 31, 32, 33, 34, and 35, respectively. Charged roll assembly 13 is the same as shown in FIGURE 1 and is rotatably mounted as already described. Doffers 30 to 35 are secured to shafts 111 to 116, respectively, each of the latter being rotatably mounted on conventional bearings (not shown). Fibers are fed into the region of electrostatic field in chamber 28 and aligned. The fiber fractions are removed in a like manner; however, any number of doffers may be used to fractionate the fibers into as many fractions as desired and into any desired length groups. Doifer rolls 30; 31, 32, 33, 34, and 35 are spaced from a maximum to a minimum distance to remove decreasing-length fractions of fibers. Again the fiber fractions are removed. from the dolfers by suction air which is fed into the doifer housings as noted above. As in the case of the embodiment shown in FIG- URE 1, the smallest fibers can be removed directly from roller 15 through duct 118 by means of any conventional suction device which will induce air into the interior of the apparatus through opening 117. Incurvate electrode 104 is segmented, i.e., physically interrupted by dofier rolls 30, 31, 32, 33, 34, and 35.
This embodiment of our invention is useful for determining fiber-length distribution of commercial samples of baled cotton, or for determining the possible breakage of the lint during the opening (of bales), cleaning (beating), picking, and carding operations, particularly the first three.
1. Apparatus for fractionating a mass of disoriented textile fibers into different length groups comprising:
(a) a rotatable first electrode;
(b) a stationary second electrode insulated from and surrounding the rotatable electrode constituting a housing therefor and a fiber separating chamber, said stationary electrode having a outer wall incurvate in the direction of rotation of said rotatable electrode, said incurvate wall and rotatable electrode together defining a fiber separation zone of decreasing width in the direction of rotation;
(c) means for rotating said rotatable electrode connected thereto;
(d) inlet means connected to the stationary electrode at the point of maximum distance between the incurvate outer wall thereof and the rotatable electrode for introducing a mass of disoriented textile fibers into the chamber formed by the stationary electrode;
(e) first outlet means connected to the stationary electrode at the point of minimum distance between the incurvate outer wall thereof and the rotatable electrode;
(f) second outlet means connected to the stationary electrode at a point intermediate said inlet and first outlet means;
(g) fiber doffing means mounted inside said second outlet means at a distance from the rotatable electrode predetermined to remove fibers of maximum average length from the disoriented mass;
(h) means connected to said stationary and rotatable electrode for applying an electric charge thereto, thereby to produce an electrostatic field of increasing potential gradient in the fiber fractionating zone defined by the incurvate wall of the stationary electrode and the rotatable electrode, said potential gradient increasing in the direction of rotation of the rotatable electrode, whereby fibers introduced through the inlet means are caused to be aligned perpendicularly to the rotatable electrode;
(i) first means connected to the fiber doffing means for removing long fibers from said dofiing means; and
(j) second means connected to the first outlet means for separately removing remaining shorter fibers through said first outlet means.
2. The apparatus of claim 1 wherein a plurality of fiber doffing means are mounted at progressively decreasing, predetermined distances fromthe rotating electrode thereby to separate the fibers into a plurality of length groups.
3. The apparatus of claim 2 wherein separate fiber removing means are connected to each of the dofling means.
4. The apparatus of claim 3 wherein the fiber removing means comprise separate air suction means connected to each of the fiber dofiing means.
5. The apparatus of claim 1 wherein the rotatable electrode is an electrically conductive cylindrical member.
6. The apparatus of claim 1 wherein the rotatable elecremoving long fibers from the dofling means and for trod comprises an electrically conductive inner cylinder removing shorter fibers through the first outlet means are and a concentric nonconductive outer .cylinder superimseparate air suction means. posed thereon.
7. The apparatus of claim 6 wherein the outer noncon- 5 References Cited ductive cylinder is mounted directly on the surface of the UNITED STATES PATENTS Inner cyhnder' 2,442,880 6/1948 Schwartz 19-155 8. The apparatus of claim 6 wherein an insulating spacer ring is mounted between the inner and outer cylinggfi Egg fig; ders to separate said cylinders. 10 pen er 9. The apparatus of claim 1 wherein the means for FRANK MLUTTER Primary Examiner.