Abstract:
The invention is particularly related to the problems of dispersing fiber to obtain a uniform distribution. The invention includes tapered ducts oriented at an appropriate angle relative to the horizontal for redirecting and decreasing the speed of an air stream containing fiber therein such that the fiber precipitates from the air stream and falls gently to form a uniform fiber bed in a bin.

Description:
This application claims benefit of Provisional No. 60/087,060 filed May 28, 1998. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to collecting dry textile fiber and delivering the collected fiber to textile machinery and more particularly to forming the collected dry textile fiber into a batt to be fed to a textile machine. 
     BACKGROUND OF THE INVENTION 
     Many types of textile processing equipment, such as carding machines and airlay web formers, are designed to receive textile fiber from a bale in the form of a batt wherein the batt is formed of a collection of tufts of fiber. In the operation of such textile equipment, the tufts are conventionally pulled or taken whole into the textile equipment. Exceptionally large tufts may overload the textile equipment by providing too much fiber at once. Thus, it is preferred that the batts are formed with smaller tufts therein and the feed rates are set to accommodate the largest remaining tufts. In addition, bale opening equipment and perhaps other equipment are used to open the bales of fiber and break the tufts into smaller clumps of fiber to facilitate less overloading of equipment and higher feed rates. 
     To better appreciate certain aspects of the present invention, a common understanding or definition of the word “tuft” is provided in U.S. Pat. No. 5,606,776 to Freund et al. (hereafter, Freund) assigned to DuPont. In any event, it should be understood that the tufts are rather light, soft, readily deformable and tend to move with and be very reactive to any flow of air in their vicinity. 
     As noted above, the feed rates of carding equipment and airlay web formers are limited by the size of the largest tufts in the batt. The batts are typically formed by chute feeders which are designed to form a batt f preferably uniform thickness and density. Such chute feeders simply stack the tufts of fiber in a channel having a width approximately that of the carding machine and a thickness of approximately the thickness of the batt. Examples of conventional chute feeders are provided in a number of issued U.S. patents, such as U.S. Pat. Nos. 3,738,476; 4,154,485; 4,449,272; 4,930,190; and 5,157,809. Another example is Freund, mentioned above, which describes an apparatus for removing fiber from bales to form a batt of uniformly distributed fiber that is fed to a web forming mechanism and wherein the apparatus incorporates a chute feeder. 
     One of the difficulties in handling cut textile fiber is the tendency for fiber in the bin portion of the chute feeder to settle in mounds or piles when it is desirable that the fiber be generally uniformly dispersed. It is a problem whether the fiber is present as individualized fiber filaments, or in clumps, tufts or the like and especially combinations thereof. Non-uniform webs are often formed as a result of the non-uniform distribution in the fiber bed at the inlet side of the chute feeder. The mounds of fiber in the bin cause heavier or denser loaded areas in the batt that correspond generally to the mounds. The denser and heavier portions can be found throughout the process and the effect is observed in the final product by variation in basis weight, particularly in the cross-machine direction. 
     There have been various approaches to addressing this problem. For example, U.S. application Ser. No. 09/163,679 filed Sep. 30, 1998 and assigned to DuPont is directed to control of the fiber delivery by using several different flow paths to provide a number of small mounds rather than a single large mound. Even though this provides some improvement in the uniformity of the batt, it has been found that further improvement can be made by controlling the flow of the air stream that transports the fiber. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to overcome the above noted drawbacks of the prior art and to provide improved distribution of fiber in a fiber handling system. 
     It is an additional object of the present invention to provide a system for receiving fiber and providing a batt having improved lateral basis weight uniformity. 
     These objects of the present invention are achieved by the provision of a fiber handling apparatus that includes an inlet attached to a pneumatic conveyor system comprising transition ducts capable of directing the air stream above and perpendicular to the fiber bed and slowing the air stream to a velocity such that the fibers fall from the air stream. More specifically, these objects of the present invention are achieved by the provision of a fiber handling apparatus that includes an inlet attached to a pneumatic conveyor system comprising transition ducts which increase in cross-sectional size from the small end at the inlet to the large end where they connect with the bin portion of the chute feeder. The ducts are positioned at an angle from the horizontal sufficient to direct the air stream above and perpendicular to the fiber bed, thereby preventing the incoming airflow from impacting the walls of the transition ducts which would cause undesirable turbulence, and further, the combination of change in cross-sectional size, angle of inclination and length provides for decrease in the air flow velocity. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may be more easily understood by reference to the accompanying drawings in which: 
     FIG. 1 is a perspective view of a preferred embodiment of a chute feeder arranged to feed a batt to a carding machine; 
     FIG. 2 is a side cross sectional view of the chute feeder and carding machine taken along line  2 — 2  of FIG. 1; 
     FIG. 3 is a perspective view of the suction box taken out of the chute feeder but which is used in the chute feeder, in part, to obtain an overlapping shingle feature of the batt; 
     FIG. 4 is an enlarged fragmentary view of the compressed batt particularly showing the overlapping shingle structure of the batt. 
     FIG. 5 presents a graphical representation of the air flow in the upper layers of a fiber bed as would be formed using a conventional chute feeder. 
     FIG. 6 presents a graphical representation of the air flow in the upper layers of a fiber bed as would be formed using the chute feeder of the claimed invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Freund is directed to imparting a particular arrangement in the batt that facilitates the batt&#39;s further processing on a carding machine or some other device known in the textile arts. The subject apparatus as presented in FIG. 2 has structural elements similar to those found in Freund, which is hereby incorporated by reference to the extent that it is consistent with the subject disclosure. 
     Referring to FIGS. 1 and 2, the chute feeder is generally indicated by the number  10  and the inlet portion of the chute feeder  10  is generally indicated by the number  200 . While the emphasis of the invention is the inlet portion  200 , the contribution of the inlet portion would perhaps be better understood if the chute feeder were more fully explained at the outset with the discussion of the operation of the inlet portion  200  being reserved until further into the text where its advantages could be more fully appreciated. 
     The chute feeder  10  is provided with fiber, as generally indicated by stream  15 , which may be provided from a suitable feed source of raw fiber  16  via conventional means, such as a pneumatic conveying system. The source  16 , as would be typical of most textile processing plants, would be fiber in tightly compacted bales. The fiber in the bales is taken from the bales and opened up by conventional equipment such as bale breakers, openers and the like and introduced into a pneumatic conveyor system (none of which are shown). The randomly oriented, staple length textile fibers may be in the form of loose, highly lofted tufts. The term “tufts” and “fibers” may be used interchangeably at various places in the specification. The chute feeder  10  is arranged to form a generally continuous batt  99  and to deliver the batt  99  for further processing such as to a carding machine, generally indicated by the number  100 . 
     As shown in FIGS. 1 and 2, the chute feeder  10  comprises a substantially closed housing, generally indicated by the number  20 , and in the preferred embodiment is generally defined by a base  21 , side walls  22  and  23  (side wall  23  is not shown but is opposite and parallel to side wall  22 ), a back wall  24 , a front wall  25  and a top wall  26 . The fiber from source  16  is delivered to a bin portion  40 . 
     The bin portion  40  is essentially a hopper for receiving fiber and providing it to the arrangement for forming a batt. This batt-forming arrangement will be described below. The bin portion  40  is generally defined by the back wall  24 , rear portions of the side walls  22  and  23 , the top wall  26  and a first dividing wall  42 . A conveyor belt  45 , carried by rolls  46  and  47 , is provided generally at the base of the bin portion  40  to receive the fiber thereon and move it forward in the chute feeder  10 . The conveyor belt  45  preferably extends the width of the bin portion  40  and may include a rough surface, slats, or the like to carry the fiber along therewith. A short ramp wall  43  extends downwardly from the back wall  24 , at an angle thereto, to a portion of the conveyor belt  45  generally at the roll  46  to substantially direct fiber onto the conveyor belt  45  so that the fiber does not pass around the conveyor  45  and get down to the bottom wall  21 . 
     The dividing wall  42  is spaced from and generally parallel to the back wall  24  to form the generally rectangular cross sectional bin  40 . Other cross sectional shapes may also be suitable, but it is preferred that the fibers are distributed laterally to the width of the batt to be formed by the chute feeder  10 . It is preferred, as shown, that the chute feeder be comparable to the operating width of the carding machine  100  or whatever textile equipment is to receive the batt  99 . The dividing wall  42  may include perforations  48  as generally indicated in FIG. 2 to allow additional air carrying the fibers to separate therefrom and pass through and out of the bin portion  40  as indicated by the arrows. The extreme upper portion of the dividing wall  42  preferably is inclined at an angle to the horizontal because if the wall were vertical it could allow undesirable collection of fiber on the wall. An angle of about 45° would be desirable. 
     A rotating drum roll  44  is positioned at the base of dividing wall  42 , and works in conjunction with the conveyor  45  to carry the bulk fiber in the bin portion  40  to the base of the inclined conveyor belt  50 . The roll  44  may also include a coarse surface to better move the fiber forward in the system, as would be known by those versed in the art. 
     The inclined conveyor belt  50  is carried by rolls  51 ,  52  and  53 , and preferably extends the width of the housing  20  of the feeder  10 . The belt  50  preferably includes spikes or other conventional implements thereon to lift fiber at a relatively steep angle (approximately 60 to 85 degrees from the horizontal) to overlie a chute portion, generally indicated by the number  70 . With the spikes on the conveyor belt  50  lifting up through a mound of fiber piled against the base thereof, the conveyor belt  50  continuously collects a substantially uniform amount of fiber for delivery to the chute portion  70 , considered in both the machine direction (MD) and the cross machine direction (XD). Leveling roll  61  is arranged to knock off excess fiber from the conveyor belt  50  and return it to the mound formed at the base thereof and therefore render a more uniform delivery of fiber to the chute portion  70 . Leveling roll  61  rotates counter to the movement of the conveyor belt  50  and may include spikes, pins or brushes to sweep away fiber that is not well secured on the spikes of the conveyor  50 . 
     As noted above, the upper portion of the conveyor  50  overlies a chute portion  70 . The chute portion  70  is a substantially vertically oriented channel having a relatively large, generally rectangular cross section and is generally defined by the front wall  25 , the front portions of side walls  22  and  23 , top wall  26  and the conveyor belt  50 . At the bottom of the chute portion  70 , is a foraminous conveyor belt  80  carried by rolls  81 ,  82  and  83 . A chute ramp  63  is positioned to extend downwardly from about the midpoint of the conveyor belt  50 , at an angle thereto, to a portion of the conveyor  80  generally at the roll  81  to direct the fiber onto the conveyor  80  in a fashion similar to the action of the short ramp wall  43  in the bin portion  40 . One of the notable attributes of the chute portion  70 , as will be explained in more detail below, is the substantial dimension at its base or, more particularly, at the conveyor belt  80 . In the preferred embodiment, the base is approximately three and a half feet long in the machine direction. It is also preferred that the chute portion  70  has at least a constant horizontal cross section or more preferably a continually increasing horizontal cross section descending from the upper portion to the base. 
     The conveyor belt  80 , as noted above, is foraminous to allow air to pass therethrough while collecting the fiber thereon. Immediately below the conveyor belt  80 , and running coextensive therewith, is a vacuum box  75  which underlies and supports the conveyor belt  80 . The vacuum box  75  extends across the width of the chute feeder  10  and coextends with the conveyor  80  for a substantial portion of the upper run between rolls  81  and  83 . The vacuum box  75  is connected to a blower  76 , of conventional design, to draw air down through the conveyor  80 . Optionally, the blower  76  may form part of the pneumatic conveyor system. 
     The chute portion  70  is arranged such that fiber is received from the conveyor  50  and proceeds down the chute portion  70  to the conveyor belt  80 . The chute feeder  10  includes an entrainment roll  62  adjacent the upper roll  52  of the conveyor belt  50  to disperse the fiber into the air flow moving down the chute portion  70 . The fiber is separated from the conveyor belt  50  by the rapidly flowing air at the top portion thereof. As best seen in FIG. 2, there is a rather narrow channel for the air to flow through between the portion of the top wall  26  and the upper portion of the conveyor  50 . The air flow as indicated by the many arrows in the FIG. 1 is concentrated in the narrow channel causing relative higher speeds for dislodging the fiber and then carrying the fiber into the upper portion of the chute portion  70 . Preferably about half of the air flow (and the fiber being carried by such air) goes over the top of the entrainment roll  62  while the other half goes under (or between the entrainment roll  62  and the conveyor  50 ) so as to fully disperse the fiber across the cross section of the chute portion  70 . It is noted that the air stream as shown by the arrows contain virtually no fiber after passing through dividing wall  42 . The air stream then picks up the fibers again when they are transported from the fiber bed up conveyor  50  to the top of chute portion  70 . The fiber is dispersed in and controlled by an air flow which descends own the chute portion  70  so as to appear like a heavy snow storm. The downward moving air flow passes through the foraminous belt  80  and continues into the vacuum box  75  and on to the blower  76 . 
     The vacuum box  75 , as best seen in FIG. 3, comprises a substantially closed box generally comprising a corrugated upper panel  140 , side panels  141  and  142 , back panel  144 , front panel  145 , a first bottom panel  146  and a second bottom panel  147 . The two bottom panels  146  and  147  intersect at a junction line  148 . The corrugated upper panel  140  has a surface which is best understood by reference to the drawings. In particular, the surface is configured with alternating peaks  140 A and valleys  140 B running generally transverse to the belt  80 . Each of the peaks  140 A and valleys  140 B are preferably arranged such that they are relatively sharply angled. Thus, the portions of the corrugated upper panel  140  which are between the peaks  140 A and valleys  140 B are generally flat portions arranged at an angle to the belt  80  which overlies the corrugated upper panel  140 . The corrugated upper panel further includes a number of openings  151  therein arranged at or near the valleys  140 B in extending transversely across the vacuum box  75 . 
     Before proceeding further with the description of the openings in the corrugated upper panel  140 , it should be noted that the vacuum box  75  functions as a conduit through which air is pulled down through the belt  80  in a particular fashion. The vacuum box can be divided into two distinct sections. A first section may be generally identified as the laydown portion  154  which generally extends across the width of the vacuum box and from the back panel  144  to about the junction line  148 . The second section is the holddown portion  155  and it comprises the remainder of the vacuum box which is fully across the box and from the junction line  148  to the front panel  145 . The laydown portion  154  may be characterized in that it has openings  151  which, as clearly shown in the drawings, are arrayed such that each succeeding valley  140 B starting from the back panel  144  has a slightly larger width or dimension than the openings in the preceding valley. The holddown portion  155  may be characterized by having openings  151  which are smaller than most if not all the openings in the laydown portion  154  and all the openings in all the valleys are approximately the same dimension. 
     The relative sizes of the laydown portion  154  to the holddown portion is preferably about three quarters laydown portion to one quarter holddown portion. However, it is anticipated that a suitable range would be to have ratio be roughly half each up to about 90 percent laydown and 10 percent holddown. In the preferred embodiment, the dimension of the openings transitions from about 24 total square inches in each valley up to about 50 square inches maximum total area. The openings in the holddown portion of the upper panel are about 16 square inches total area per valley. However, there are many factors which should be considered when designing for balanced flow such as the desired basis weight of the batt to be formed, the denier of the fiber used in the chute feeder, and the flow characteristics of the foraminous belt, etc. 
     The reason for the progressively larger series of openings  151  followed by several smaller dimension openings may be best understood by reference to FIG.  2 . The tufts are provided into the top of the chute portion  70  and are carried down to the surface of the foraminous belt  80  with the air flow therein. As a batt forms on the foraminous belt  80 , the air flow which is intended to pass therethrough encounters greater resistance where the batt is thickest. The batt would inherently be thinnest near the roll  81  and thickest near the roll  91 . Without variation in the openings  151  in the laydown portion  154 , the air flow would tend to concentrate at the portion of the belt  80  near the roll  81 . However, by varying the dimension of the openings, the air flow is generally balanced over the entire laydown portion  154 . As such, the batt being formed accumulates fiber thereon in a more uniform manner. In other words, the resistance of air flow through the corrugated upper panel  140  is preferably arranged such that it offsets the increase in resistance created by fiber collecting on the belt  80 . 
     As a result, the tufts actually form thin layers or shingles, which successively overlap in a manner that each successive shingle is slightly offset in the machine direction from the one below it. The formation of the shingles is clearly the result of the air being drawn down through the belt  80  and the tufts being so light to follow the air flow. The air naturally takes the path of least resistance which is where the fiber batt is the thinnest and the tufts that follow the air flow will quickly fill the voids. This process occurs continuously and is difficult to see when watching the chute feeder in operation. However, the batt  99  has clearly discernible layers formed therein that can be seen upon close inspection and disassembly of the batt  99 . The improved operation of the textile machinery to which the batt is fed is also quite discernible. 
     In addition to forming thin shingles of generally uniform thickness, the system provides a naturally self-balancing lateral distribution of the fibers across the width of the batt to be formed. Uniformity of the batt (in terms of basis weight) across the width thereof is a particular concern as it is important for product quality as well as efficient use of raw material. A batt that has thin portions is not acceptable to customers and product that has excessively thick portions is wasteful of fiber (if it is acceptable for its intended use). The lateral distribution is accomplished in generally the same manner as described above, in that the air flow will favor the path of least resistance. The least resistance will be where the batt is the thinnest. As the air flow moves to the thinnest portion of the batt, it brings additional fiber with it which brings the amount of fiber at the thin portion up to a more uniform distribution. Although a certain amount of lateral uniformity is achieved when the batt is so formed, the subject invention provides an even greater degree of uniformity. 
     As described above, the adjacent layers or shingles within the batt are slightly offset from one another in a longitudinal direction because of the movement of the belt  80 . The number of shingles which form the thickness of the batt  99  is dependent on a number of factors including the designed basis weight or total thickness of the batt  99 , the length of the base of the chute portion  70 , the nature of the tufts and the rate of operation of the chute feeder  10 . By reference to FIG. 4, which will described in more detail below, there is illustrated a batt having about three and a half to four shingles in thickness when cut perpendicular to the length of the batt  99 . In the preferred arrangement the batt would have more shingle layers, but for drawing clarity, the drawing shows fewer layers. 
     Referring again to FIGS. 2 and 3, once the batt  99  is formed on the belt  80  in the laydown portion  154 , it passes under roll  91 . Thereafter, the batt  99  is held down on the belt  80  over the holddown portion  155  of the vacuum box  75  in preparation for feeding to the card  100 . The holddown portion tends to keep the batt from expanding significantly and also prevents it from being pulled back under the roll  91  by the very strong air flow in the laydown portion  154 . The smaller dimension openings in the holddown portion  155  are suited to allow sufficient air flow therethrough to hold down the batt  99  substantially in its compressed state until the batt is to be pinched between subsequent rollers. 
     The compressed batt  99  is thereafter suited for delivery to the card  100 . Carding machines are very old and well known and the card  100  is intended to represent any conventional design. In particular, the card  100  includes suitable feed rolls  105  which maintain the tight squeeze on the batt  99  as it is fed to lickerin roll  111 . Lickerin roll  111  has a plurality of sharp needle like teeth for picking up the fiber from the batt  99 . The lickerin roll  111  rotates substantially faster than the rate at which the batt  99  is fed thereto; however, with the batt tightly pinched between feed rolls  105  and the tufts arranged in overlapping shingles, the lickerin  111  is not able to easily pull out entire tufts intact. In the drawing, the lickerin  111  is provided with stripper and worker rolls  112  and  113 . 
     The card  100  further includes a main carding roll and a plurality of stripper and worker rolls  116  and  117  both associated with the lickerin and with the main carding roll  115 . The fiber that has been carded is then doffed by doffing roll  119  and discharged from the card. Once the fibers are carded they are more thoroughly separated from one another and arranged generally parallel to one another in the machine direction. 
     Although the card  100  has been described as being conventional, using the batt formed by this process and apparatus enables an operator of a conventional card to increase its throughput dramatically. Typically, cards are not able to be fed substantial rates of fiber because cards become quickly overloaded rendering product with many neps and streaks which are very difficult if not impossible to remove. If the overloading is substantial and for extended periods of time, the card may overheat and melt most polymer fibers. While this is rare and very unlikely under present operating scenarios, using conventionally assembled batts at the feed rates that have been found possible with the chute feeder of the present invention would cause significant streaking, nepping, overheating and perhaps many other significant but uncommon problems. However, in contrast to such beliefs or expectations, carding machines have been found to be able to produce quality product at the significantly higher feed rates. The difference is not that more fiber is being loaded onto fully loaded portions of the card, but that the new batt is able to more fully utilize the full capacity of the card. 
     To put this in other terms, when using a conventional batt, full tufts are picked up by the lickerin. If a large tuft or a clump of tufts is picked up by the lickerin whole, the card would probably be overloaded at that position and the web product would reveal the consequences. The conventional manner of avoiding this likelihood is to set the feed rate so that the card has the opportunity to handle large tufts. Thus, the feedrate across the full width of the card would be considerably irregular such that in some places, a tuft is being pulled in and the rate is at a maximum, while at others, there is little being added to the card and the feed rate is substantially below capacity. The feedrate across the width of the card is normalized such that the there are fewer and less radically low feedrate portions across the width of the card. The tufts in the new batt are either dismantled as the fiber therein is picked up by the lickerin or the tuft remains somewhat intact but significantly drafted out. It may be helpful to visualize the batt of the present invention being “nibbled” by the lickerin roll in a substantially uniform manner across the width thereof rather than the irregular “bites” of individual tufts being fed from a conventionally formed batt. 
     A way of filling in the gaps on the carding roll has been developed so that more of the card is operating at or near capacity. As noted above, test results indicate that obtaining a feed rate improvement (i.e. the rate at which the batt is fed to the carding machine and not the speed at which the carding machine is run) of at least three times conventional feed rates is feasible while even higher feed rates are envisioned. 
     A section of the batt  99  is enlarged in FIG. 4 to more clearly show the angle of the shingles to the batt. In the preferred embodiment, the angles and lengths of the shingles are more extreme than shown, but for purposes of explanation and clarity, the angle and length dimension are shown as being less substantial. However, this notable difference between what would be preferred and what is illustrated should not have a bearing on what is covered by the claims which follow this description. 
     Continuing with the description of FIG. 4, the batt  99  is illustrated as being compressed between rolls wherein the dimensions of interest are the lengthwise dimension component L of the shingle in the batt  99 , the thickness of the compressed batt t, and the angle X formed by the length L and thickness t. By simple trigonometry, the angle of the shingle in the batt may be derived by obtaining the arctan of t/L. This angle or the plane in which the shingle lies may also be described as the tuft plane since this is the general plane in which the flattened tufts are arranged. It should further be understood that these dimensions and angles are measured while the batt  99  is compressed. Since the batt is intended to be fed to a textile machine, the batt  99  will most likely be compressed between rolls to control the delivery of the batt. Because this primarily relates to the form of the batt as it is delivered to the equipment, the measurement is most relevant in its compressed state. 
     It is also illustrated in FIG. 4 that the batt is fed in a somewhat radial orientation to the lickerin  111 . The lickerin  111 , as is conventional, has a card clothing exterior surface which includes many teeth. By arranging the shingles or tuft at the angle illustrated, the compressive forces exerted by the feed rollers  105  cause adjacent tufts to hold the remaining portions of the tuft in the batt while the fibers at the edge of the tuft are pulled out of the tuft without being able to easily pull the remainder of the tuft out. 
     In actual use trials of chute feeders it was found that large voids were being formed in the fiber bed and that the fibers were being churned violently through the fiber bed. It was believed that these effects on the fiber bed were the result of uncontrolled air flow at excessive speeds as the air stream entered the top part of the bin of the chute feeders and was forced down through the fiber bed. 
     The conclusions from the aforementioned online testing were confirmed by using Computational Fluid Dynamics (CFD) software from Fluent, Inc. (Lebanon, N.H.). It was found that the disturbance of the fiber bed in the conventional chute feeders was caused by high-speed, nonuniform air flow being directed onto the fiber bed by the chute feeder inlets. The speed of the air stream in the inlet pipes was found to be as high as 20 m/s in the positive vertical (upward) direction. It was found that the air stream in the chute feeder disclosed in the Freund patent could have a speed as high as 5 m/s in the negative vertical (downward) direction. Such a high air stream speed impinging on the fiber bed can result in the aforementioned non-uniformities. 
     Concentrating on the inlet portion  200  in the FIG. 2, it is arranged to receive the fiber from source  16  as indicated by stream  15  by conventional means such as a pneumatic conveying system. The pneumatic conveying system is in communication with transition ducts  217  that transport the air stream  15  to the top of bin portion  40  of the chute feeder  10 . The fiber is dispersed in and controlled by the air stream. It should be noted that throughout the specification, the terms “fiber”, “air”, “air stream”, “airflow” and the like may all, depending on context, refer generally to a stream or flow of air transporting fibers. Although not shown, the pneumatic conveying system may, as needed, comprise inlet pipes that connect to the small ends of the transition ducts  217  to provide a straightening effect to the air stream before it enters the transition ducts  217 . Such inlet pipes may be needed if the arrangement of the pneumatic conveying system would otherwise cause the air stream to enter the transition ducts  217  so that the air stream would impact on the walls of the ducts. 
     The speed of the air stream is important in determining how the fiber bed may be formed. When the speed just above the fiber bed is too high, the fibers are retained in the air stream and also turbulence is created which thereby contributes to the undesirable non-uniformity in the fiber bed. However, when the air flow is slowed sufficiently the fiber can precipitate out from the air stream and descend relatively slowly within the bin portion  40  so as to appear like a snowfall and thereby form the desired uniform fiber bed. It has been found that under certain conditions the speed of the air stream should be less than about 2 m/s. 
     This desired reduction in the speed of the air stream is accomplished by the transition ducts  217  which typically increase in cross-sectional size from a relatively smaller end to a relatively large end at the juncture with bin portion  40 . As shown in FIG. 2, the axis  215  of duct  217  is at an angle of about 10 degrees from the horizontal. This angle is not expressly limited to 10 degrees, but rather is chosen to cause the airflow speed to decrease to a speed low enough to prevent the incoming airflow from impacting the walls of the transition ducts  217  or the walls of the chute feeder at the top of the bin portion  40 . The transition ducts  217  may be of any shape, but are typically circular and there should be about a three-fold increase from the small end to the large end at the outlet at the top of bin portion  40  of the chute feeder. One embodiment would have a cross-sectional size of about 1 m at the large end that decreases to about 0.3 m at the small end. In addition to controlling the speed of the air stream, the transition ducts  217  direct the air stream so that the greater part of the air stream does not travel vertically downward and impinge on the fiber bed, thereby causing turbulence and holes in the fiber bed. The transition ducts  217  address this problem by directing the air stream above and perpendicular to the fiber bed and generally toward the top of conveyor  50 . Thereby, the transition ducts  217  substantially eliminate the holes and other non-uniformities in the fiber bed. 
     A conventional chute feeder and the claimed chute feeder were both modeled using the CFD program and the speed of the air flow into the respective fiber beds of each was determined. FIG. 5 presents a CFD graph of the air flow in the upper layers of a fiber bed as would be formed using a conventional chute feeder. FIG. 6 presents a CFD graph of the air flow in the upper layers of a fiber bed as would be formed using the chute feeder as in the claimed invention. The graphs in the Figures depict the speed of the air flow in the upper layers of the respective fiber beds with lower speeds indicative of increased uniformity. As such, the uniformity of the fiber bed with the claimed invention is presented as much better than that achieved with conventional chute feeders.