US3041676A - Apparatus for producing a heterogeneous diffusion of fibers - Google Patents

Description

July 3, 1962 J. H. GOLDMAN APPARATUS FOR PRODUCING A HETEROGENEOUS DIFFUSION OF FIBERS 2 Sheets-Sheet 1 Filed May 19, 1958 INVENTOR.

JOSHUA H. GOLDMAN ATTORNEY July 3, 1962 J. H. GOLDMAN 3,041,676

APPARATUS FOR PRODUCING A HETEROGENEOUS DIFFUSION OF FIBERS Filed May 19, 1958 2 Sheets-Sheet 2 INVENTOR. JOSHUA H. GOLDMAN ATTOR N E? Unite States Patent M 3,641 676 APPARATUS FOR PRODIICING A I-IETEROGENE- OUS DIFFUSIQN 0F FIBERS Joshua H. Goldman, Box 14, Hadlyme, Conn. Filed May 19, 1958, Ser. No. 736,339

8 (Iiaims. (Cl. 19-155) My present invention relates to the distribution of fibers and more particularly to a novel apparatus for producing a heterogeneous diffusion of fibers.

This application is a continuation in part of my copending application Serial No. 335,376, filed February 5, 1953, issued July 1, 1958, Patent No. 2,841,204.

The principal object of the present invention is to provide an apparatus for distributing fibers in a heterogeneous non-parallel and non-oriented relation.

Another object of the present invention is to provide an apparatus for forming a thin fibrous web having tensile strength longitudinally and transversely in the plane of the web as well as at right angles to the plane of the web. A further object of the present invention is to provide an apparatus which produces a centrifugal force on high speed rolls to throw the fibers and form a chaotically'disposed mass of fibers.

Another object of the present invention is to provide an apparatus for forming a non-woven fibrousweband for impregnating or coating the web or both.

With the above and other objects and advantageous features in view, my invention consists of a novel arrangement of parts, more fully disclosed'in the detailed description following, in conjunction with the accompanying drawings, and more particularly defined in the appended claims.

In the drawings, 7

FIG. 1 is a longitudinal section, partly diagrammatic, of an apparatus embodying my invention.

FIG. 2 is a view similar to FIG. 1 of the coating device.

FIG. 3 is a view similar to FIG. 1 of the impregnation device.

It has been found desirable to provide a fibrous material in an extremely thin non-woven web composed of intertwined fibers. Such a web has many uses both in industry and in medicine. In my United States Patents No. 2,039,312, entitled Reinforced Carded Webs, I have shown a method which will produce a web having considerable tensile strength longitudinally in the plane of the web. However, it will be found that the web separates quiteeasily transversely to the plane of'the web. In my copending application hereinabove refer'redto I have described a novel method of producing a fibrous web having considerable tensile strength both longitudinally and transversely in the plane of the web.

The present invention describes a machine for carrying out this novel method. The machine of the present invention comprises a series of rotating rolls designed to segregate, attenuate and disburse the fibers and a con.- denser on which the web is formed. Provision is also made for coating or impregnating the web or both. The desired web can be made of any fibrous material, either natural or artificial, or blends thereof. The principal portion of the apparatus of the present invention comprises a plurality of high speed rolls which attenuate and throw the fibers by centrifugal force. Thereafter the fibers may be condensed on any desiredsur-face and in any desired manner. In the illustrated form, the web is formed by condensing the fibers on condensing rolls.

In a conventional card the rolls are so arranged and the speed so regulated that the function of the card to clean and align the fibers is realized. The function of the present invention is to disperse the fibers by subjecting Patented July 3, 1962 them to sufiicient centrifugal force to enable them to be thrown in a chaotic pattern on to a condensing surface.

FIG. 1 shows a preferred arrangement of rolls designed to accomplish the desired purpose. The fibers 10 may be in the form of picker lap, sliver or cut staple. The fibers are fed along a plate 11 having an integral vertical portion 12 which tapers to a sharp edge and extends between the rolls 13 and 14. The roll 13 is mounted just above the plate 11 and constitutes the feed roll. The roll 13 is provided with pins or metallic clothing 15 in the conventional manner. The feed roll 13 serves to feed a predetermined quantity of fibers to the chelater roll 14 which is also provided with a toothed surface 16. The feed roll 13 rotates counterclockwise and the chelater roll 14 also rotates counterclockwise. The spacing between the feed.

and chelater rolls is .005" to .010". The pins 15 on the 1 chelater roll 14 present a uniform film of unintentionally aligned fibers which the roll 17 attenuates and separates. The distributor roll 17 also rotates counterclockwise at a maximum clearance of .002 from the roll 14. A plate 18 is positioned between the rolls 14 and 17 and is provided with a tapered edge extending sharply between the rolls. Here again the fibers are removed from the surface of the roll 14 by the roll 17 across the edge of the plate 18. The surface of the roll 17 may be similar to that of the rolls 13 and 14, having pins or metallic clothing, or the surface may be merely roughened with engraved flutes or fine thread.

Applicant has found that the operation of the device of the present invention is practically self-cleaning. The fibers on the sinface of the roll 14 will be transferred to the roll 17 cleanly. However, certain types of fibers may have a tendency to resist transfer and a few fibers may be left on the roll. To prevent a build up of untransferred fibers a clearing roll 19 may be used as shown in FIG. 1. The roll 19 is provided with metallic clothing 20 on its outer surface and straddles the rolls 14 and 17 with a clearance of approximately .005". This roll rotates clockwise and will clear the fibers from the roll 14 to the roll 17.

Adjacent the roll 17 is a diffusion roll 21 rotating clockwise. The clearance between the surfaces of the rolls 17 and 21 should be no greater than .0005". The surface of the roll 21 may be identical withthe roll 17. The roll 21 removes the fibers from the surface of the roll 17 and throws them by centrifugal force in a defined path through the duct 22 on to the condensing rolls 23 and 24. The condensing rolls 23 and 24 are positioned one over the other as illustrated in FIG. 1, the upper roll 23 rotating counterclockwise and the lower roll 24 rotating clockwise. The surface of the condensing rolls are foraminous and their speed of rotation determines the density of the web 25 formed thereon.

A metallic shield 26 extends around all the rolls except the feed roll 13 and, of course, the condensing rolls 23 and 24. The shield 26 is positioned not more than .020" from the surface of the rolls and the inside surface of the shield 26 is ground and polished. At the upper portion of the roll 17, adjacent the clearing roll 19, the shield 26 is provided with a small gap 27 for bleeding off any excess entrapped air. \I

The size and speed of the feed roll 13 is not critical. The diameter-length ratio must be great enough to resist bending and the speed is governed by the quantity of stock bedded in the teeth. The diameter and the revolutions per minute of the roll 14 are therefore critical. I have found that a diameter of six inches and speed of 900 rpm. is a minimum for satisfactory performance.

The surface speed of the distributor roll 17 should be not less than twice that of the roll 14 in order that the fiber stock be further opened and attenuated. This roll is.

therefore illustrated as having a much greater diameter than the roll .14 to provide the indicated surface speed. As has been heretofore pointed out this roll may be provided with pins, metallic clothing or milled or engraved grooves.

The speed and diameter of the diffusion roll 21 is the most critical. The fibers are removed from roll 17 by roll 21 whose speed must be suflicient to throw the fibers by centrifugal force which is equal to the mass of the fibers multiplied by the square of their velocity and divided by the radius of the roll. I have found that a speed of 2000 rpm. and a diameter of six inches is a minimum for fibers of high density and I have used speeds of, 6000 rpm. with light fibers. The surface of the roll 21 is similar to that of the roll 17 and may be fine metallic or flexible clothing or, if the velocity is high, may be an etched or engraved surface. This is possible because the fibers are transferred, conducted and thrown at the rolls 17 and 21 by the boundary layer of air surrounding the roll rather than the roll itself. This boundary layer of air is held close to the rolls and restricted by the shield 26 which is concentric with the rolls. At the point of discharge the impetus given to the fibers by the velocity of the roll 21 is maintained by the stream of air which leaves the roll with the fibers. No extraneous air is introduced to conduct the fibers nor is any negative pressure used to collect them on the condenser rolls.

The conveyance of fibers by air is well known to the alt. Suoh a system has many disadvantages residing in the fact that the airborne fibers tend to agglomerate and that the air stream moves with a laminar flow through the ducts. Also the fibers tend to travel in parallel relation with the air flow. For these reasons discrete fibers cannot be transported successfully by and the system is mainly used in the process of forming picker lap.

The apparatus of the present invention is therefore designed to throw the fibers in discrete form by centrifugal force rather than carry them by a moving mass of air. The velocity acquired by the fibers will be directly pro portional to their mass, their density, the force applied and inversely proportional to the viscosity of the ambient medium. The mass of each fiber is small but the density is high particularly when exposed to an atmosphere of high humidity. The apparatus therefore applies a force of a high order of magnitude. For example, using the approximate formula:

Diameter in feei' r.1:o.1:a. 6000 and considering a six inch roll revolving at 6000 r.p.m. we would obtain a force equal to 3000 times the force of gravity.

When the product of the mass, density and force is divided by the viscosity an exceedingly large velocity results. This is true because the viscosity is nearly equal to zero due to the fact that the boundary layer of air is moving at the same speed as the fibers so that no relative motion exists. As an example of the energy imparted, the apparatus of the present invention has propelled one inch cotton fibers a distance offifteenfeet from the surface of a five and one half inch roll rotating at 4225 rpm.

Note that surface speed controls the relation between Force in g units= the rolls 13 and 14, but is not significant with respect to fibers, the final roll 21 must develop a centrifugal force g in accordance with the above described formula. This force depends on the speed-radius relation of the roll. For example, applicant has constructed a roll 3" in diameter rotating at 10,000 rpm. This develops a force of more than 4000 gs.

The fibers leave the surface of the roll 21 in a well defined trajectory. To prevent turbulence the inner surfaces of the duct 22 must be smooth and designed to conform to the path of the fibers. The duct 22 should be approximately eight times the diameter of the roll 21 in length. The curvature of the upper and lower walls may be plotted by standard formulae.

The condenser rolls 23 and 24 collect the fibers which leave the roll in the form of a web 25 which comprises a heterogeneous mass of non-parallel fibers. The web 25 can of course be used in this form for many purposes such as filtering, as an absorbent, etc. However, such webs are in many cases either impregnated or coated or both. FIGS. 2. and 3 are schematic views of arrangements for impregnating and coating. Since the apparatus distributes the fibers in a heterogeneous mass, they can be condensed on any surface requiring reinforcement with such fibers. For example, in manufacturing plastic fiberglass tubing, the plastic tubing can be used as the condensing surface and glass fibers may be thrown by the device on to the plastic tubing. Similarly other fibers can be thrown on irregular surfaces such as suit cases, auto bodies, etc.

FIG. 2 illustrates one formof coating device. The web 25 may be fed directly from the web-forming apparatus shown in FIG. 1 or the impregating arrangement shown in FIG. 3. It may be passed around a feed roll 28 over a large roll 29 rotating clockwise. Disposed above and slightly to one side of the roll 29 is the transfer roll 30 which actually lays the coating on the web 25. Note that the transfer roll 30 also rotates clockwise. Excess V coating is removed from the surface of the roll 30 by a doctor blade 31. The reservoir of coating material 32 is positioned above the transfer roll 30 and designed to provide the surface of the roll 30 with the coating material. To make sure that no excessive coating is provided and that the coating is uniform, a metering roll 33, rotating clockwise, abuts the roll 30. A doctor blade 34 is provided to remove the coating from the metering roll 33 back into the reservoir. With the above arrangement a coating of any desired type may be laid on the upper surface of the web 25. Similarly a second coating may be laid on the other side of the Web if desired. The type of coating and method of drying may be varied to suit any requirements.

FIG. 3 illustrates an arrangement which can be used for impregnating the web 25. Where the web is to be impregnated and coated it must of course be first impregnated. The web 25 is impregnated by passing the web between the rolls 35 and 36. The roll 35 may be immersed in a reservoir 37 of the impregnating solution. The roll 35 rotates clockwise and the roll 36 rotates counterclockwise. A triangular dam 38 is provided at each end between the rolls 35 and 36 for preventing excessive amounts of solution from overflowing. The impregnated web passes around the roll 36 which rotates counterclockwise and through a drying area utilizing a drying apparatus 39 which may be of any desired type, such as heat, infra-red light, etc. The impregnated web 25 may then be passed through a series of calender rolls 40.

The size and width of the individual rolls can of course be varied to suit different requirements within the limitations imposed by diameter-length relation to prevent bending or whipping. It is only necessary that the comparative speeds between rolls and the minimum speeds herein indicated be maintained. At these extremely high speeds the roll should be well. balanced and preferably individually driven for better control. It will be noted that roll 17 is approximately twice the diameter of the roll 14 and has an indicated surface speed of approxi-' I the rolls and the shield without the rough physical contact in a conventional card. As a result the present apparatus will handle fibers, such as glass fibers, which are extremely brittle and normally impossible to card or separate without pulverizing. The apparatus of the present invention therefore produces a disruption of the parallelism of the fibers to form a non-woven heterogeneous mass of non-parallel fibers evenly distributed and of substantially uniform Weight throughout. When properly processed, the resultant web can be made-extremely thin, extremely light, and with a high tensile strength in every direction in the plane of the web. The product can be made highly absorbent, as, for example, with cotton fibers. It can also be treated to make it waterproof. It can be dyed and it can be stiffened. The web can be used for insulation, for wiping cloths, and in many other applications.

The apparatus can readily be adapted to other uses. For example, the separation of long and short fibers is a slow and costly process. In View of the formula set forth herein it is obvious that a longer fiber, having more mass will be thrown further by the apparatus than a shorter fiber. The applicant has found that the apparatus will discharge a stream of fibers at high speed when the condensing rolls are removed with the longer fibers at the far end of the trajectory and the shorter fibers closer to the apparatus. If bins are provided for the fibers to fall into, the apparatus can readily be used as a high speed separator. This effect is only possible where the fibers are propelled by centrifugal force. Note that when fibers are propelled by a stream of air under pressure, the heavier fibers will fall first and the lighter ones will go further and this only within the confines of the apparatus. Other advantages and uses of the apparatus of the present invention will be readily apparent to a person skilled in the art.

I claim:

1. An apparatus for distributing fibers by centrifugal force in a non-parallel non-oriented relation, comprising a rotatably mounted chelater roll, a distributor roll rotatably mounted adjacent said chelater roll and rotating in the same direction, a diffusion roll rotatably mounted ad jacent said distributor roll and rotating in the opposite direction, said rolls rotating at progressively higher speeds, said diffusion roll imparting a centrifugal throwing force to the fibers passing through the apparatus, and shielding extending concentrically around the non-adjacent surfaces of said chelater, distributor and diffusion rolls and spaced not more than .020" therefrom.

2. An apparatus for distributing fibers by centrifugal force in a non-parallel non-oriented relation, comprising a rotatably mounted chelater roll, a distributor roll rotatably mounted adjacent said chelater roll and rotating in the same direction, a diffusion roll rotatably mounted adjacent said disnibutor roll and rotating in the opposite direction, said rolls rotating at progressively higher speeds, said diffusion roll imparting a centrifugal throwing force to the fibers passing through the apparatus, and shielding extending concentrically around the non-adjacent surfaces of said chelater, distributor and diffusion rolls and spaced not more than .020" therefrom, said chelater roll being covered with metallic clothing, said distributor roll having a roughened surface and being spaced not more than .00 from said chelater roll, said diffusion roll having 6 a roughened surface and being spaced not more than .0005 from said distributor roll.

3. An apparatus for distributing fibers by centrifugal force in a non-parallel non-oriented relation, comprising a rotatably mounted chelater roll, a distributor roll rotatably mounted adjacent said chelater roll and rotating in the same direction, a diffusion roll rotatably mounted adjacent said distributor roll and rotating in the opposite direction, said rolls rotating at progressively higher speeds, said diffusion roll imparting a centriugal throwing force to the fibers passing through the apparatus, a feed roll rotatably mounted in front of said chelater roll, an L- shaped feed plate extending beneath said feed roll, the vertical leg of said plate having a wedge edge extending between said feed and chelater rolls, shielding extending concentrically around the non-adjacent surfaces of said chelater, distributor and diffusion rolls and spaced not more than 0.20" therefrom, said shielding being internally ground and polished, a duct extending from said diffusion roll to receive the thrown fibers, and condenser means at the open end of said duct to form said fibers into a non-wovenweb, said chelater roll being covered with metallic clothing, said distributor roll having a roughened surface and being spaced not more than .002" from said chelater roll, said diffusion roll having a roughened surface and being spaced not more than .0005 from said distributor roll.

4. An apparatus for distributing fibers by centrifugal force in a non-parallel non-oriented relation, comprising a rotatably mounted chelater roll, a distributor roll rotat ably mounted adjacent said chelater roll androtating in the samedirection, a Wedge-shaped plate extending upwardly between said chelater and distributor rolls, a diffusion roll rotatably mounted adjacent said distributor roll and rotating in the opposite direction, said rolls rotating at progressively higher speeds, said diffusion roll imparting a centrifugal throwing force to the fibers passing through the apparatus, a feed roll rotatably mounted in front of said chelater roll, an L-shaped feed plate extending beneath said feed roll, the vertical leg of said plate having a wedge edge extending between said feed and chelater rolls, and shielding extending concentrically around the non-adjacent surfaces of said chelater, distributor and diffusion rolls and slightly spaced therefrom, a duct extending from said diffusion roll to receive the thrown fibers, and condenser means at the open end of said duct to form said fibers into a non-woven web, and a clearing roll rotatably mounted above said chelater and distributor rolls and spaced .005" from each, said shielding extending around said clearing roll, said chelater roll being covered with metallic clothing, said distributor roll having a roughened surface and being spaced not more than .00 from said chelater roll, said diffusion roll having a roughened surface and being spaced not more than .0005" from said distributor roll.

5. An apparatus for distributing fibers by centrifugal force in a non-parallel non-oriented relation, comprising a rotatably mounted chelater roll, a distributor'roll rotatably mounted adjacent said chelater roll and rotating in the same direction, a diffusion roll rotatably mounted adjacent said distributor roll and rotating in the opposite I direction, said rolls rotating at progressively higherspeeds, said diffusion roll imparting a centrifugal throwing force to the fibers passing through the apparatus, and shielding extending concentrically around the non-adjacent surfaces of said chelater, distributor and diffusion rolls and spaced not more than .020" therefrom, said diffusion roll having a minimum diameter of 6" with a minimum speed of 2000 rpm.

6. An apparatus for distributing fibers by centrifugal force in a non-parallel non-oriented relation, comprising a rotatably mounted chelater roll, a distributor roll rotatably mounted adjacent said chelater roll and rotating in the same direction, a diffusion roll rotatably mounted adjacent said distributor roll and rotating in the opposite direction, said rolls rotating at progressively higher speeds,

7 said diffusion roll imparting a centrifugal throwing force tween said feed and chelater rolls, shielding extending concentrically around the non-adjacent surfaces of said chelater, distributor and dilfusion rolls and spaced not more than .020" therefrom, said shielding beiug'internally ground and polished, a duct extending from said diffusion roll to receive the thrown fibers, and condenser means at the open end of said duct to form said fibers into a non-woven web, said diffusion roll having a minimum diameter of 6" with a minimum speed of 2000 rpm.

7. An apparatus for distributing'fibers by centrifugal force in a non-parallel non-oriented relation, comprising a rotatably mounted chelater roll, a distributor roll rotatably mounted adjacent said chelater roll and rotating in the same direction, a diffusion roll rotatably mounted adjacent said distributor roll and rotating in the opposite direction, said rolls rotating at progressively higher speeds, said diifusion roll imparting a centrifugal throwing force to the fibers passing through the apparatus, and shielding extending concentrically around the non-adjacent surfaces of said chelater, distributor and diffusion rolls and spaced not more than .020" therefrom, said chelater roll being covered with metallic clothing, said distributor roll having a roughened surface and being spaced not more than .002" from said chelater roll, said diffusion roll having a roughened surface and being spaced not more than .0005" from said distributor roll, said difiusion roll having a minimum diameter of 6 with a minimum speed of 2000 r.p.m.

8. An'apparatus for distributing fibers by centrifugal force in a non-parallel non-oriented relation, comprising a rotatably mounted chelater roll, a distributor roll rotatably mounted adjacent said chelater roll and rotating in the same direction, a diffusion roll rotatably mounted adjacent said distributor roll and rotating in the opposite direction, said rolls rotating at progressively higher speeds, said diifusion roll imparting a centrifugal throwing force to the fibers passing through the apparatus, a feed roll rotatably mounted infront of said chelater roll, an L- shaped feed plate extending beneath said feed roll, the vertical leg of said plate having a wedge edge extending between said feed and chelater rolls, shielding extending concentrically around the non-adjacent surfaces of said chelater, distributor and diffusion rolls and spaced not more than .020 therefrom, said shielding being internally ground and polished, a duct extending from said diffusion roll to receive the thrown fibers, and condenser means at the open end of said duct to form said fibers into a nonwoven web, said chelater roll being covered with metallic clothing, said distributor roll having a roughened surface and being spaced not more than .002" from said chelater roll, said dilfusion roll having a roughened surface and being spaced not more than .0005 from said distributor roll, said diifusion roll having a minimum diameter of 6" with a minimum speed of 2000 r.p.m.

References Cited in the file of this patent nil.

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