US3442204A - Automatic damper mechanism for baling staple fibers - Google Patents

Description

May 6, 1969 D, CCANLESS ETAL 3,442,204

AUTOMATIC DAMPER MECHANISM FOR BALING STAPLE FIBERS Filed April 4, 1966 Com'muous FILAMENT EXTRUSION COLLECTION OF PLUEALITY or- CONTINUOU$ FlLAMENTs To Foam Tow BUNBLE CmMPmG Tow iLAM ENT&

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United States Patent 3,442,204 .AUTOMATIC DAMPER MECHANISM FOR BALING STAPLE FIBERS Stuart D. McCanless and Irvin V. Plowden, Rock Hill, S.C., assignors to Celanese Corporation, New York, N.Y., a corporation of Delaware Filed Apr. 4, 1966, Ser. No. 539,841 Int. Cl. B30b 9/30 U.S. Cl. 100--35 6 Claims ABSTRACT OF THE DISCLOSURE Staple fiber bales are provided of more uniform dimensions and density by depositing the fibers in a more uniform layer. Such a layer is provided by altering the forward course of travel of the fibers during the conveying thereof, and just prior to their being condensed into a layer over some predetermined sequence and period of time.

This invention relates to the manufacture of staple fibers from continuous filaments. It particularly relates to an improved process and apparatus for baling staple fibers to obtain bales of relatively uniform dimensions an density and of increased overall weight.

While man-made continuous filaments or fibers have, as is deemed well known, many advantageous properties, such as tenacity, etc., they also lack some of the desirable properites of natural staple fibers, e.g., cotton, wool, and the like, such as cover, bulkiness, hand, insulating properties, etc. In an effort to attain the desirable advantages and properties of both man-made and natural fibers, a considerable proportion of man-made continuous fiber production is cut into staple fiber lengths and is thereafter processed as staple fibers, both in textile and nontextile end-uses. To provide the textile industry with man-made staple fibers, the man-made fiber producer cuts a continuous filament tow, i.e., a bundle of continuous filaments, into staple fiber lengths, as desired by the staple fiber processor, of from less than about one inch to as much as fifteen inches. Staple fibers or bunches thereof, after leaving the tow cutting operation, are conveyed by an air stream through a conveyor duct and are condensed or deposited as a layer of randomly arranged staple fibers on a rotating condenser screen positioned above a bale press box. The fibers are picked-off the rotating condenser screen by pick-up rolls, drop into a conveyor chute and are periodically kicked into the bale press box. After each kicking, the staple fibers kicked into the bale press box are tamped by a hydraulic ram or tamper. When the required volume of fibers as determined by a volume control device, such as the maximum pressure allowed to be exerted on the staple fibers in the bale press box by the tamper or the like,-has been deposited in the bale press box, the body or volume of fibers isthen pressed by a hydraulic ram to the desired final volume. The density limits, i.e., the weight of fibers in the final volume, is determined by the handling characteristics of the staple fibers during subsequent staple processing. Thestaple fibers are then baled, much like cotton or woolen staple fibers, in rectangular cardboard carton wrapped with steel bands, and the bales of man-made staple fibers are then shipped to the staple fiber processor who either processes thestaple fibers through one of the commonly known staple systems to form a staple fiber yarn or through a nontextile system to form e.g., fibrous batting for use in comforters, quilted linings, furniture batting and the like.

The problem with which our invention is concerned originates with the baling operation which is attendant with numerous problems and disadvantages. The bales of manmade staple fibers produced heretofore are quite often non-uniform in size or dimensions, e.g., a bale instead of having relatively flat surfaces, as is desired, may often have one or more surfaces which bulge in the middle or which bulge or protrude more on one end than the other, or the like, resulting in a number of problems, as hereinafter mentioned. As is readily apparent, a bale which is non-uniform in size must necessarily be non-uniform in density. For example, a bulge in the center of the bale means that a greater volume of fibers has been deposited in the center of the bale than in the outer edges. Upon pressing, the fibers in the center of the bale are therefore compressed or densified to some degree before the fibers in the outer portions of the bale are subjected to compression. This non-uniform density makes for problems in subsequent staple processing, e.g., areas of staple fibers of high density are more diflicult to open, i.e., separate fibers from one another, than are areas of lesser density.

Moreover, bales of staple fibers having uneven dimensions frequently result in damage to the baling press, need be rebaled, or even in some instances scrapped. In addition to press damage, rebaling costs and the like, uneven bales and bales which vary from one another over a relatively wide weight range result in added storage, handling, and transportation costs. Not only are there economic considerations related to uneven staple fiber bales, but severe safety considerations are also involved. An uneven bale can kick the press doors open violently when they are released. Also, the metal bands of an uneven bale, apparently because of highly localized stresses in the bands, are prone to break when the bale is being handled, and personnel handling the bale or standing close by are therefore subject to serious injury.

In order to produce bales of uniform size and dimension and uniform density the staple fibers must be evenly distributed across the bale press box, as is more fully explained hereinafter.

It has been determined that uneven bales and bales of non-uniform density result from the lack of a balanced flow condition, i.e., instead of fibers being uniformly distributed over the rotating condenser screen or roll, they are found to be deposited more on one side than the other or to deposit more in the middle of the roll than on the side, or the like. The flow is found to be sensitive to anything that :alfects the air flow in the conveying system, which may, to name a few reasons, include the condition of the exhaust filters, lack of cleanliness of the conveyor and exhaust ducting, condition of the condenser screen seals, cleanliness of the condenser screen, and the like.

In an endeavor to provide more uniform distribution of the staple fibers on the condenser screen, and therefore more uniform bale density and dimensions, the flow of fibers through the conveyor system has been, in the past, subjected to a damping force of air, hereinafter more fully explained. The staple fiber conveyor duct, through which air is being pulled and entrained therewith staple fibers, is provided about the periphery thereof, with a plurality of holes or ports of about four inches diameter. A metal sleeve having one port or hole located therein of approximately the same diameter as the ports in the conveyor duct is positioned on the conveyor duct over the ports or holes therein. When the flow of fibers is observed to deposit unevenly on the condenser screen or roll the hole in the sleeve is then manually rotated and aligned with a suitable hole in the conveyor duct. The theory is that the flow pattern of fibers being deposited onto the condenser screen can be altered or changed by aligning the two holes, i.e., the hole in the sleeve and the one in the conveyor duct, whereby a stream of air is pulled into the conveyor duct which, because the con veyor duct is always under negative pressure, acts as a force opposed at substantially right angles to the conveying flow of staple fibers, thus causing the fiber deposition pattern on the condensing roll to be altered. As one can readily see, this procedure of attempting to alter the flow pattern is wholly a trial and error operation. Even though operating personnel devote a considerable amount of time manually adjusting the sleeve, staple fiber bales are still consistently produced with non-uniform dimensions and density, varying bale weights, and the problems and disadvantages above-mentioned.

It is, therefore, the primary object of this invention to overcome the problems and disadvantages above-mentioned.

It is also an object to provide a process for consistently producing staple fiber bales of relatively uniform dimension and density.

It is another object of this invention to provide a process for consistently producing a plurality of staple fiber bales, each of which has relatively the same overall bale weight.

It is a further object to produce staple fiber bales having an overall increased density over those currently available for a specific staple fiber.

An additional object is to provide new and improved apparatus for baling staple fibers whereby staple fiber bales having relatively uniform dimension and density are produced.

Other objects will become apparent in the detailed description which follows, reference being had to the accompanying drawings, wherein:

FIGURE 1 shows a block diagram describing staple fiber manufacture and processing thereof to a staple fiber yarn;

FIGURE 2 is a perspective of a baling operation;

FIGURE 3 shows a damper which has been used heretofore; and

FIGURE 4 is a perspective view showing the damping apparatus according to our invention.

It has now been determined that the foregoing objects can be accomplished by allowing or causing a side flow of air to enter the conveyor duct substantially at right angles to the flow of staple fibers so that it will hit or impinge upon the flow of fibers periodically at a plurality of predetermined points around the periphery of the flow of fibers according to some predetermined time sequence and length of time.

Referring now more specifically to the drawings, in FIGURE 1 there is shown a block diagram, which is deemed self-explanatory, describing the various operations involved in the manufacture of man-made staple yarns. In FIGURE 2 is shown, indicated generally by reference numeral 1, an apparatus for forming a bale of man-made staple fibers.

As indicated in FIGURE 1 of the drawing, filaments are extruded through spinnerettes according to known procedures (by apparatus not shown) and a plurality of these filaments are gathered together and are formed into a tow bundle, i.e., a bundle of filaments. The filaments are then crimped and are subsequently cut or broken to form fibers of staple fiber lengths according to conventional and well-known techniques. The staple fibers are then conveyed by air, in a direction indicated by the arrows (FIGURE 2) through a conveyor duct 2, transition ducting 3 and impinge upon and are distributed or deposited in a layer in relatively random fashion upon the surface of perforated condenser screen 4 rotating in the counter clockwise direction, viewed from the left side of the figure, and as indicated by the arrow. The staple fibers, not shown for purposes of clarity, are held on the surface of rotating screen 4 due to the negative pressure which exists in the system created by the air being pulled through conveyor duct 2, transition ducting 3, rotating screen 4 via perforations 5 therein, and passageways 6, 7 by a blower or fan, not shown in the drawing. The fibers are picked-off rotating screen 4 by pickup rolls 8 and fall onto a chute, which for sake of clarity and because it forms no part of the invention, is not shown in the drawing. The staple fibers are then kicked or pushed according to conventional techniques known to those in the baling art and fall into bale press box 9 in a relatively random fashion to form layers of staple fibers indicated generally by reference numeral 10. Between each kicking operation, the staple fibers in bale press box 9 are tamped by a hydraulic tamper or the like (not shown). When the desired volume of staple fibers has been collected in the bale press box, which volume in turn is known to result in a desired bale density limit upon subsequent pressing to a certain set pressure, the staple fibers in the bale press box are then, according to usual baling techniques, compressed and baled, i.e., wrapped in cardboard and burlap and banded with steel. bands.

Our invention will now be more fully described with reference being had first to the device used heretofore. Prior to transition ducting 3, there is located in conveyor duct 2 a plurality of holes, ports or openings 11 around the periphery thereof as is shown in FIGURE 3, through which air may be drawn into conveyor duct 2. Heretofore, in an attempt to alter the general flow of fibers through duct 2 and therefore the distribution of fibers on perforated condenser screen 4, the damping apparatus, as is shown in FIGURE 3, has been used. The sleeve 12, having a single hole 13 therein, of approximately the same size as the holes 11 in conveyor duct 2, is manually rotated or positioned on the conveyor duct as indicated by the arrow so that the hole 13 on the sleeve 12 matches with a suitable hole 11 in the conveyor duct 2. Air is then allowed to be pulled into the conveyor duct 2 in an attempt to influence the flow pattern and distribute the staple fibers on the surface of the condenser screen 4 in the desired manner.

As is now deemed quite apparent, such operation and apparatus, as above-described, results in a very unstable distribution of staple fibers onto rotating condenser screen 4; hence, into the bale press box 9. As before explained, the flow pattern of air and entrained fibers through duct 2 onto screen 4 depends upon numerous factors, e.g., condition of blower air filters, cleanliness of duct 2 and exhaust ducting, condition of the condenser screen seals, cleanliness of the condenser, the cutter being used, speed of the cutter, leaks in the system, and the like. Any one of these factors can cause a change in the flow pattern immediately after operating personnel have positioned sleeve hole 13 over a particular duct hole 11 in order to compensate for previous erratic flow, i.e., uneven distribution of staple fibers on the condenser 4. Operating personnel have, in the past, spent a considerable amount of time in manually adjusting sleeve 12 to alter the flow pattern of the staple fibers without attaining any substantial better uniformity of bale dimensions or density than without such apparatus.

It has been concluded therefore that there are so many variables that constantly and continuously influence the flow pattern of staple fibers in the conveyor duct, and therefore deposition onto the condenser that any instantaneous alteration therein cannot be adequately compensated for by a single stepwise procedure such as is provided for by the damper described above and which is shown in FIGURE 3.

We have now discovered, however, that a stable fiber bale of relatively uniform dimensions and density and of substantially greater overall weight can be produced by periodically and systematically allowing air to enter the conveyor duct 2 at substantially right angles to the flow of staple fibers from various locations around the duct periphery over some controlled sequence and period of time. Not only can bales of greater uniformity be produced with respect to shape and density but, quite unexpectedly, and contrary to popular belief, bales of greater overall weight process as well, and in most instances better, during staple processing than do bales of lesser overall Weight. Apparently, and we do not wish to be limited by this theory, the better performance of the heavier bales of staple fibers, attained as a result of the invention herein described, is the result of more uniform density. The tight or hard spots existing heretofore in staple fiber bales are eliminated by our invention. Moreover, the peak density, as determined by the thumb test and which is hereinafter more fully described, is less than in the staple fiber bales produced heretofore.

According to our invention, there is shown in FIGURE 4 an automatic damping system for uniformly distributing staple fibers onto perforated condenser screen 4. Conveyor duct 2 is provided with a plurality of holes or ports, preferably three in number, as is shown in the figure. Also, quite desirably, two of the ports 14, 15 are directly opposed to one another and are more or less in alignment with the axis of condenser 4 while the third port 16 is intermediate the two opposed ports 14, 15 at the bottom of conveyor duct 2. This allows air to enter conveyor duct 2 from either side and the bottom of the duct 2 just ahead of transition ducting 3. It is preferable to have the ports at no greater substantial distance from the beginning of the transition ducting than the diameter of the conveyor duct. Otherwise, the influence of the air flow through ports 14, 15, 16 upon the flow pattern of staple fibers is reduced to an undesirable degree.

Although the diameter of the ports and the number thereof may depend to some extend upon the size of the conveyor duct, air flow, etc., it has been determined that for a conveyor duct of about fifteen inches, three ports of about four inches diameter are preferable. Of course, it is realized that the port size may be smaller with a greater number thereof, or that a greater number of ports may be required with less air flow in the system, and the like.

In each of the three ports 14, 15, 16 (FIGURE 4) there is located a double acting air cylinder 17, 18, 19, each of which is controlled by a 4-way solenoid valve (not shown) according to conventional control techniques to reciprocate plungers 20, 21, 22 whereby valves 23, 24, 25 attached thereto can be opened to allow air to enter into conveyor duct 2 or closed to prevent air from entering the duct. The three solenoid valves, above-mentioned, are in turn controlled by a conventional three-circuit cam timer (not shown). The length of time that each port is open can, of course, be varied by setting the timer, which may range from as little as about ten seconds to as much as about one minute or more, with a maximum of five minutes, however, a period of thirty to forty-five seconds has been found highly preferable.

If staple fibers are allowed to collect on one side of the bale press box for too long a period of time, a layer of staple fibers in the shape of a wedge is formed which makes for difficulties in subsequent pressing. Even though an equal weight or layer of fibers is allowed to deposit on the opposite side of the bale press box, the pressing problem remains. When pressure is applied to the bale, the bale does not hold together properly. It slips apart upon being pressed much like two wedges, which are superposed to form a cube, do upon being pressed. For optimum results, the ports 14, 15, 16 are opened and closed in a continuous repeating cycle as shown in the table below:

Units of time Port 1 2 3 Close..." Close. Open Do. ...do... Close Open.

the invention in its broader aspects is not to be construed as limited thereto.

EXAMPLE A cellulose acetate dope comprising cellulose acetate in acetone solvent was extruded in a metier in conventional fashion through a multihole spinnerette having circular holes to produce a plurality of continuous filaments having a filament denier of about 8.0. The filaments from several metier positions were assembled together in known fashion to produce a bundle of filaments or tow having a total denier of about 288,000. The tow bundle was crirnped in the usual fashion and then was forwarded to a cutting position where a knife cut the tow into approximately 1 inch staple fibers. The staple fibers were then conveyed by air through a conveyor system to a bale press box and were pressed under a pressure of about lbs./ in. and baled into bales of staple fibers, A damper, according to our invention, was operated to open and close the ports 14, 15, 16 in a continuous repeating cycle, ports 14, 15 being open for approximately 40 seconds while port 16, the bottom port, was open for about 10 seconds. A bale of staple fibers was produced having relatively uniform dimensions of about 25" x 49" x 43" and having a relative uniform density of about 17 pounds per cubic foot. In all 278 bales were produced resulting in no non-uniform bales, hereinafter further described. The bales were found to have an overall weight of about 475 :35 pounds. Heretofore, the same size bales had an overall weight of only about 400135 pounds. Quite unexpectedly, no adjustments were required in the cycle established for operation of the damper mechanism according to our invention other than that required in the initial setting.

The staple fibers were subsequently processed on a Hunter garnett according to usual techniques into both 17 ounce and 20 ounce per yard batting 81 inches wide. Contrary to expectations, the staple fibers, although from bales of much greater overall weight than usually processed, processed as well as the lesser weight bales and yielded a superior web in terms of compression and cohesiveness.

Whether a bale is of uniform dimensions and density or not, as referred to in the above example, and throughout the specification, can be determined by the following tests:

(1) Observation.-This is of course the simplest test for determining bale uniformity. Some bales can readily be discounted as being non-uniform. For example, if the bale breaks apart during baling or if it does not have a good cubic shape, e.g., it is extremely lop-sided, it is then classified non-uniform and must in most instances be re-baled.

(2) Measwement.-This is a more definitive test for determining whether a staple fiber bale is of uniform dimensions or not. In a bale press box, e.g., having dimen sions of 24" x 48" x 42" a bale of staple fibers having the dimensions 25 x 49" x 43" is desirably produced, thus taking in consideration normal expansion of the fibers in the bale. The bale is still considered to be of uniform dimensions if it has a good cubic shape even if it expands, however, to as much as 45 inches. Preferably an expansion to no more than 44 inches is desired. However, if the bale is lope-sided, i.e., varies from about 45 inches at one end to about 41 inches on the other end or is 45 inches in the middle and 41 inches on the end or the like, it is considered non-uniform and must be rebaled. In other words, the bales to be classified of uniform dimensions by measurement must not vary at the ends thereof more than plus or minus three inches of the measurement taken at the middle of the bale, Preferably, they vary less than plus or minus two inches, and quite desirably vary less than plus or minus one inch.

(3) Thumb test.Staple fiber bales, 'when pressed in various areas thereof with the thumb, are found to be relatively soft in some areas and much harder in other areas when they are not of uniform dimensions as above described. A uniformly dense bale on the other hand, is of relatively the same hardnes throughout.

Although this invention :has been described with particular reference to cellulose acetate staple fibers, it is to be understood, of course, that it is equally applicable to the baling of any staple fibers, for example, polyester fibers, nylon, and acrylic fibers.

We claim:

1. In a process for baling staple fibers including the steps of conveying the fibers in a fluid stream to a condensing zone, condensing the fibers into a layer of randomly arranged fibers, collecting a plurality of layers of the said fibers, and pressing said layers together thereby forming a bale of staple fibers, the improvement comprising subjecting the fibers in the fluid stream prior to the condensing thereof to a plurality of forces, said forces being directed in a direction approximately perpendicular to the fiber containing fluid stream whereby the forward direction of the fibers is altered and a more uniform layer of fibers is condensed, thus resulting in a bale of relatively uniform dimensions and density.

2. Process according to claim 1 wherein the fluid stream of :fibers is subjected to said forces over some predetermined sequence and period of time.

3. Process according to claim 1 wherein the plurality of forces are a plurality of streams of air.

4. Process according to claim 3 wherein said air streams are located equidistant around the periphery of the fiber containing fluid conveying stream.

5. Process according to claim 3 wherein two of said air streams are directly opposed to one another, while the third air stream is interposed intermediate said two streams, the flow of each of said air streams being over a predetermined sequence for a predetermined period of time, whereby the fibers are uniformly distributed on the condenser and hence the bale box to form a bale of staple fibers of relatively uniform dimensions and density.

6. In combination with apparatus for baling staple fibers comprising a press means, a bale press box, condenser means, and means for conveying said fibers in a fluid stream to said condenser means, a means' for uniformly distributing the fibers in the bale press'box whereby a bale of relatively uniform dimensions and density is provided, said last named means comprising a conveyor duct having a plurality of spaced-apart holes arranged around the periphery thereof, valve means in each of said holes, and timing means to open and close each of said valves over a predetermined time sequence whereby fluid is allowed to enter the conveyor duct, thereby to alter the forward direction of the fibers in the conveying "fluid stream.

References Cited Caughlin 19.- l56.4

PETER FELDMAN, Primary Examiner."

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