IL111520A - Device for cleaning fibers - Google Patents

Description

A DEVICE FOR CLEANING FIBERS 111,520/2 The present invention relates to a device for cleaning fibers such as cotton fibers, by removing waste particles therefrom.

More particularly, the present invention provides an apparatus which uses a selected combination of processes such as carding, separation, expansion, application of centrifugal force, crushing, pulverising, air streams and the action of gravity for separating such particles which are embedded in the fiber mass.

As has been explained in detail in Israel Patent Application 101,168, cotton is transported in bale form, the cotton being highly compressed and each bale weighing about 400 to 500 pounds.

The steps for transforming the baled cotton into fine cotton yarn are multiple, and require different stages of processing in different machines which have been developed over the past two hundred years.

As described in the literature, e.g., in Manual of Cotton Spinning, Textile Institute and Butterworth & Co. Ltd. (1965), after the opening of a bale, one of the first stages of processing is performed with a carding machine. Carding is defined as the reduction of an entangled mass of fibers to a filmy web by working the fibers between two closely spaced, relatively moving surfaces clothed with sharp points.

As reported in said Manual, baled cotton contains a small percentage of trash, i.e. particles of leaf, seed, coat and stalk from the cotton plant and also sand and soil from the ground in which the plants were grown, and about - 2 - 111,520/2 70-80% of this trash falls away when the bale is opened. The remaining 20-30% is imprisoned in the tufts of cotton, and some of it is firmly attached to the fibers themselves. It is a function of the carding process to remove as much of the trash as possible from the cotton. The fine action of the card breaks up the tufts and therefore releases some of the trash for rejection, and the wire surfaces on the carding parts retain a proportion of the residue so that after carding, a percentage of the original trash, depending on the type of trash and on the carding action, is left in the sliver.

During processing, cotton is fed to a doffer of a carding machine, but some trash is still present at this stage. It is obvious that high quality textiles cannot be produced unless such particles are removed from the fibers. Furthermore, such particles, if not removed, are likely to damage or erode operating components of spinning and other machinery used for further processing, or to cause stoppages due to thread breakage.

Traditional combing machines arranged to effect such separation are complicated and do not have high throughput rates. Furthermore, such machines tend to damage the fibers with the consequent inclusion of an undesirably high percentage of short fibers in the material being processed. Short fibers are detrimental to the spinning process and reduce the tensile strength of the produced thread.

It is therefore one of the objects of the present invention to obviate the disadvantages of the prior art devices for separating trash particles from textile fibers, and to provide an apparatus using toothed rollers which is operable at a high throughput rate. - 3 - 111,520/2 It is a further object of the present invention to remove such trash particles from the textile fibers, while preventing damage or length reduction to the fibers being processed.

The present invention achieves the above objectives by providing an apparatus for cleaning fibers by means of a combination of revolving toothed rollers, the fiber mass being divided, expanded and recombined while being successively transferred over at least four rollers; the outer surface of at least one of said rollers revolving in close proximity to, but spaced apart from, two other rollers to form a triangular enclosure therebetween, said apparatus comprising a first roller arranged to collect fibers from a moving supply source and to effect the division and carding thereof; a second roller driven at a peripheral speed different from that of said first roller, arranged to collect at least a part of said fibers from said first roller and to expand said fiber mass collected therefrom; a third roller driven at least 5 times faster than either said first or said second roller, and arranged to receive, expand, card and eject fibers from said first roller and said second roller, and to eject waste particles from said fibers; a fourth roller arranged to receive, collect and condense fibers from at least said third roller, and at least one separator blade held in proximity to one of said rollers for separating waste particles.

In a preferred embodiment of the present invention, there is provided an apparatus for cleaning fibers wherein a separating blade is held under and in proximity to at least one of said rollers, whereby heavy waste particles impinge on said blade and are separated from said fibers by gravity, centrifugal force, and aerodynamic forces. - 4 - 111,520/2 It will thus be realized that the novel fiber-dirt separator apparatus of the present invention divides and expands the fiber mass to ease removal of particles embedded therein. As separation of toothed rollers is maintained, these operations are carried out without tearing the fibers .

In an especially preferred embodiment of the present invention, said first roller is provided with dual-function teeth, a portion of said teeth being arranged to effect the collection of fibers from said supply source and another portion of said teeth being formed to affect carding in conjunction with an adjacent toothed roller.

The various separation modes provided by the invention take into account the fact that not all waste particles are alike. For example, separation by centrifugal force is most effective for high density particles, such as those of metal; separation by air stream is effective for low density particles, and crushing and pulverising are suitable for hard, brittle waste such as soil.

The high output rates and simplicity of the mechanism are made possible by using revolving rollers while avoiding reciprocating components .

As is known in the literature, fundamentally, there are two important actions, performed with carding surfaces: carding and stripping. The action which takes place between two clothed surfaces depends upon the inclination of the wire and/or teeth, and the direction and rate of their motion in relation to each other. - 5 - 111,520/2 Carding action is accomplished when the wires or teeth of the two surfaces are inclined in opposite directions. The direction and rates of motion should be such that one surface passes the other point against point. This action may result from both surfaces going in the same direction, with the lower surface moving rapidly past the upper surface; or the action may be obtained by having the surfaces move in opposite directions, each in the direction of inclination of the wires or teeth. Carding action results in complete opening of the tufts of the lap.

Stripping action is accomplished when the wires or teeth of two surfaces point in the same direction. With this arrangement, the action is point against smooth side. The surface which moves the faster lifts the cotton away from the other wire or tooth, and collects it. Stripping is used in transferring cotton from one surface to another, and in removing it from a surface.

The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures so that it may be more fully understood.

With specific reference now to the figures in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with 6 - 111,520/3 the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

In the drawings: Fig. 1 is a schematic view of a preferred embodiment of the apparatus according to the invention; Fig. 2 is a detailed, schematic view of part of the same apparatus shown in Fig. 1, but without the fibers; Fig. 3 is a schematic view of the detail of an apparatus similar to that shown in Fig. 1, but wherein the distributor roller is provided with dual-function teeth; Figs. 3A and 3B are schematic views of two different formations of toothed wires for use in the present invention; Fig. 3C is a schematic view of a different roller combination, having a preopener roller provided with various formations of toothed wires on the surface thereof, with said toothed wires being shown in enlarged scale on the right-hand side of said Figure; Fig. 4 is a schematic view of the detail of an apparatus provided with an air suction tube in proximity to three rollers; Fig. 5 is a schematic view of apparatus with a trap for waste particles; Fig. 6 is a schematic view of the detail of an apparatus similar to that shown in Fig. 1, but wherein the condensing roller is provided with fiber-engaging teeth; [Fig. 7 is a schematic view of the detail of an apparatus wherein a second separation blade is provided; - 7 - 111,520/3 jFig. 8 is a schematic view of apparatus equipped with rollers having point-to-point teeth; Fig. 9 is a schematic view of an apparatus wherein the fibers are returned to the doffer after preliminary cleaning, and are again removed therefrom for further processing; Fig. 10 is a schematic view of an embodiment of the invention which is provided with a condenser roller, and Fig. 11 is a schematic view of an embodiment of the invention which is provided with futher additional rollers.

There is seen in Fig. 1 an apparatus 10 for cleaning fibers 12 by means of a combination of revolving toothed rollers. Apparatus 10 causes the fiber mass to be divided, expanded and recombined while being successively transferred over at least four rollers 14, 16, 18, 20, as will be described further below.

The outer surface of roller 14 revolves in close proximity to, but spaced apart from, two other rollers 16, 18, as seen in the detail shown in Fig. 2. A roughly triangular enclosure 22 is formed between the rollers 14, 16, 18. Enclosure 22 has been found to prevent undesired air turbulence and is beneficial for the prevention of unintended fiber dispersal.

A first roller 14, which is the distributor roller, is provided with teeth 24 arranged to collect fibers 12 from a moving supply source 26, here shown as a doffer. The first roller 14 is driven in the direction of the arrow at about 200 revolutions per minute (RPM) . Advantageously, the - 8 - 111,520/3 peripheral speed of the first roller is up to 20% higher than the peripheral speed of the supply source 26.

A second roller 16, which is the preopener roller, is driven at a peripheral speed different from the first roller 14. In this embodiment, the speed of the second roller is greater than that of the first roller. It is provided with teeth 28 which are arranged to collect part, but not all, of the fibers 12 from the first roller 14. Due to the different peripheral speeds of these rollers, the fiber mass is expanded; as only a portion of the fiber mass is collected by the second roller, the fiber mass is also divided.

A third roller 18, which is the combing roller, is driven at least 5 times faster than either the first or the second roller 14, 16. In this embodiment, the third roller 18 is driven at about 3000 PM. The third roller 18 has teeth 30 which are finer than those of rollers 14, 16. The third roller 18 typically has a diameter of between 10 and 25 cm.

The combing roller receives fibers from the preopener roller, expands and cards them, and, due to large centrifugal forces, ejects waste particles onto the surface of the distributing roller, where they are held by fibers. The combing roller receives fibers from the distributing roller, expands them, and, due to the fact that the waste particles are situated on the fibers on the surface of the distributing roller, effectively ejects them into the zone of interaction with separator blade 32.

An optional fourth roller 20, which is a condensing roller, is arranged to collect, receive, and condense the fibers from - 9 - 111,520/3 the third roller 18 for transfer to the next processing stage.

A separator blade 32 extends along the length of third roller 18 and is held in proximity thereto. Fibers 12 pass underneath blade 32, but the shortest fibers and waste particles 34 impinge the blade side 36. Furthermore, waste particles and fibers which are situated on the outer layer of the surface of combing roller 18 interact effectively with separator blade 32, thus improving the cleaning of fibers 12. The particles 34 enter a dust passage 37, which leads from the vicinity of separator blade 32 to a dust collection container 38.

The doffer may revolve in the same direction as the distributor roller, or in the opposite direction.

Fig. 3 depicts the details of apparatus 39, which is similar to that shown in Fig. 1. In this embodiment, the first distributor roller 40 is provided with dual-function toothed wires 42. A first tooth edge 44 of each toothed wire 42 is arranged to effect collection of fibers 12 from the supply source 26 seen in Fig. 1, and an opposite edge 46 is formed to effect carding in conjunction with an adjacent toothed roller 16, the preopener roller.

The dual function of tooth edges 44, 46 may be achieved by providing two separate, adjacently aligned toothed wires having teeth facing in opposite directions, as shown in Fig. 3A, or by forming an especially designed, single wire having dual function teeth, as shown in Fig. 3B.

The preopener roller 16 may also be provided with dual-function teeth, and may revolve in either the clockwise or - 10 - 111,520/3 counter-clockwise direction, resulting in the improved carding of fibers.

The distributor roller 14 and the preopener roller 16 effect carding in two stages: first between the roller 14 and the preopener roller 16, and, in the second stage, between the roller 14 and the combing roller 18, and between the preopener roller 16 and the combing roller 18. The resulting improved orientation of fibers 12 is helpful in the following stages of the process.

Fig. 3C illustrates application of the preopener and combing rollers arranged between the cylinder and a doffer of a carding machine, together with an additional condensing roller, wherein dual-function card wires are provided on the surface of said preopener roller.

Fig. 4 illustrates the details of an apparatus 58 for cleaning fibers, further provided with a tube 60 positioned in the curved triangle 22 formed between three toothed rollers 14, 16 and 18. Tube 60 may be used for supplying a flow of compressed air; it may be perforated, and may revolve for improved moving of fibers. The supplied air flow reduces air turbulence caused by the revolving toothed rollers 14, 16 and 18, and prevents fiber intertangle.

Fig. 5 depicts details of an apparatus 58 for cleaning fibers, further provided with a trap for waste particles, which are collected and removed as part of the cleaning process through the application of suction. Distances Lx and L2 define the efficiency of the cleaning of the fibers.

Air gaps "a" and "b" define the velocity of the air stream between separator blade 32 and plate 37, and allow - 11 - 111,520/3 the regulation of the quantity and quality of waste 34 which is ejected.

Referring now to Fig. 6, there is seen apparatus 48 for cleaning fibers, wherein condensing roller 20 is provided with fiber-engaging teeth 52 and is driven at a peripheral speed about 5 times less than that of the combing roller 18. Teeth 52 slope in the direction opposite to that in which the condensing roller 20 is driven, and consequently collect the major portion of fibers from combing roller 18. The air gap "d" between rollers 18 and 20 lies in the range of from 0.2 to 1.5 mm. Distance "e", signifying the air gap between the rear face of separator blade 32 and teeth 52, is in the range of from 5 to 12 mm. Gap "e" is kept small, to prevent fibers from flowing therethrough.

Seen in Fig. 7 is an apparatus 66 for cleaning fibers 12, wherein a separating blade 68 is held under and in proximity to a first roller 14. Thereby, heavy waste particles 70 impinge on the blade 68 and are separated from fibers 12 by gravity and centrifugal force.

Apparatus 66 includes a stripping roller 69 which removes any fibers 12 remaining on the distributor roller 14 and the combing roller 18, and transfers these fibers to the air condensor 116, where all fibers are collected. A fiber retainer guard 71 is shown partially surrounding some of the rollers; the guard 71 reduces fiber loss from the roller periphery.

Fig. 8 illustrates triangular enclosure 14, 18, 16, showing that the direction of the teeth of each two adjacent rollers is point against point. The preopener roller rotates slowly, about 20% less than the speed of the - 12 - 111,520/ 3 distributing roller. The combing roller cards fibers between the teeth of both the distributing roller and the preopener roller.

Fig. 9 shows another embodiment of apparatus 98 for cleaning fibers.

Rollers 102, 104, 106 are in surface proximity and have mutually different peripheral velocities. This embodiment operates without an additional condensing roller.

Typical roller speeds are as follows: the distributor roller operates at a speed of up to about 20% more than the speed of the doffer 26; the preopener roller 104 operates at a speed of either about 20% more, or 20% less, than the distributor roller, and the combing roller 106 operates at a speed of about 10 times that of the distributor roller.

A separator blade 108 is held in proximity to combing roller 106, and waste 110 is extracted by suction means from near the combing roller 106, which returns the cleaned fibers to the supply source 12, shown as a doffer, for further processing by known grooved roller 88, crush rolls 90, 92, and take-off roller 118.

A further embodiment of an apparatus 114 for cleaning fibers 12 is shown in Fig. 10. While generally similar to previously-described embodiments, this embodiment is provided with a condenser 116 in addition to the condensing fourth roller 20 described with reference to Fig. 1, which collects most of the fibers from the combing roller 18.

Condenser 116 collects some of the fibers from the combing roller 18, although being substantially spaced apart - 13 - 111,520/2 therefrom. These collected fibers are then transferred to take-off roller 118, which thus receives fibers from two sources .

The embodiment of Fig. 10 also includes a toothed working roller 124. Experiments have shown that roller 124 improves the effectiveness of dust separation in combination with separator blade 32.

Fig. 11 shows another embodiment of the apparatus 120, having a compression roller 122. Roller 122 is smooth and serves to stabilize air currents. It also helps to compress the fibers onto condensing roller 20.

Also shown in Fig. 11 are a working roller 124 and a stripping roller 126, which serve to improve the fiber cleaning.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the essential attributes thereof, and it is therefore desired that the present embodiments be considered in all respects as illustrative and not restrictive, reference being made to the appended claims, rather than to the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (14)

- 14 - 111,520/2 WHAT IS CLAIMED IS:

1. An apparatus for cleaning fibers by means of a combination of revolving toothed rollers, the fiber mass being divided, expanded and recombined while being successively transferred over at least four rollers; the outer surface of at least one of said rollers revolving in close proximity to, but spaced apart from, two other rollers to form a triangular enclosure therebetween, said apparatus comprising: a first roller arranged to collect fibers from a moving supply source and to effect the division and carding thereof ; a second roller driven at a peripheral speed different from that of said first roller, arranged to collect at least a part of said fibers from said first roller and to expand said fiber mass collected therefrom; a third roller driven at least 5 times faster than either said first or said second roller, and arranged to receive, expand, card and eject fibers from said first roller and said second roller, and to eject waste particles from said fibers; a fourth roller arranged to receive, collect and condense fibers from at least said third roller, and at least one separator blade held in proximity to one of said rollers for separating waste particles.

2. An apparatus according to claim 1 , wherein the direction of the teeth in each two adjacent rollers of said triangular enclosure is point against point. - 15 - 111,520/2

3. An apparatus according to claim 1, wherein said first roller is provided with dual-function teeth, a portion of said teeth being arranged to effect the collection of fibers from said supply source and another portion of said teeth being formed to affect carding in conjunction with an adjacent toothed roller.

4. An apparatus according to claim 1, wherein a tube is rotated into said triangular enclosure to prevent undesired air turbulence.

5. An apparatus according to claim 4, wherein said tube is perforated for supplying a flow of compressed air.

6. An apparatus according to claim 1, further comprising a dust passage leading from the vicinity of said separator blade to a dust collection container.

7. An apparatus according to claim 1, further comprising an open trap for collection of dust and waste particles positioned within said triangular enclosure.

8. An apparatus according to claim 7, wherein said dust and waste particles are collected into said open trap by means of suction. 16 111 ,520/3

9. An apparatus according to claim 1 , wherein the last roller of said apparatus is arranged to effect the return of cleaned fibers to said supply source for further processing by other apparatus.

10. An apparatus according to claim 9, wherein said supply source is a doffer.

11. The appartus according to claim 1 , wherein the outer surface of at least one of said rollers revolves in close proximity to, but spaced apart from, two other rollers to form a triangular enclosure therebetween, and wherein a separator is disposed in said triangular enclosure to prevent undesired air turbulence.

12. The apparatus according to claim 11 , wherein said separator is arranged for separating dust and waste particles from fibers into an open trap, to be collected therein.

13. The apparatus according to claim 12, wherein said dust and waste particles are collected in said open trap by means of suction.

14. The apparatus according to claim 1 , wherein said first roller is a doffer of a carding machine. For the Applicant WOLFF, BREGMAN AND GOLLER