US2541305A - Production of textile materials - Google Patents

Description

Feb. 13, 1951 w. I. TAYLOR 2,541,305

PRODUCTION OF TEXTILE MATERIALS Filed June 23, 1949 o 59] o o o o o If) I Q? FIGZ. FIG .I.

Inventor WI- TA YLOR Patented Feb. 13, 1951 PRODUCTION OF TEXTILE MATERIALS William Ivan Taylor, Spondon, near Derby,'England, assignor to Celanese Corporation of America, a corporation of Delaware Application June 23, 1949, Serial No. 100,883 In Great Britain July 2, 1948 25 Claims.

This invention relates to the production of textile materials and in particular to the production of artificial continuous filaments in the form of very heavy bundles, or tows of filaments, a form which is especially useful for the conversion of the continuous filaments into staple fibres.

One method of producing continuous artificial filaments is the method known as dry spinning, in which a film-forming liquid, e. g. a solution of cellulose acetate in a volatile solvent such as acetone, is extruded in the form of filaments through a spinning jet having a number of small orifices into a gaseous setting medium in which the filaments harden. It is anobject of the present invention to provide a dry-spinning apparatus of a form especially advantageous for the production of continuous filaments in the form of heavy bundles or tows suitable for conversion into staple fibres.

According to the present invention an apparatus for the production by dry spinning ofa heavy bundle or tow of continuous filaments comprises a vertical spinning cell, a plurality of ranks of multi-orifice jets in the upper part of said cell, one rank within another, each rank consisting of a number of jets arranged round the middle of said cell, the jets of each inner rank being at a higher level than those of the rank immediately outside it, and the top of the cell being stepped back so that all the jets are accessible through openings in the sides of the cell, the cell being formed at the bottom with a space common to the filaments from all said jets, and means for collecting all said filaments in tow form. Thus the cell is stepped back immediately above the first or outermost rank of jets, to render accessible the jets of the second rank, within and above the first. If a third rank is provided within the first two, it can be disposed at a higher level than the second rank, the top of the cell being again stepped back immediately above the second rank of jets, and so on. By these means a very large number of spinning jets, each producing a number of separate filaments, can be compactly accommodated in a single spinning cell occupying but little fioor space, while permitting ready access to each of the jets for servicing of the jets and for their replacement when nec essary.

In describing the invention in greater detail hereafter, reference will be made to the accompanying drawings which show, by way of example, one form of spinning apparatus according to the invention and in which,

Figure 1 is a front elevation, partly in section, of the spinning cell and,

Figure 2 is an inverted sectional plan taken on the line 2-2 of Figure 1.

The apparatus shown in the drawing comprises a vertical spinning cell I having a number of multi-orifice jets 2 in the upper part thereof, the jets being arranged round the middle part 3 of the cell in two ranks 4, 5, one Within the other. The jets of the inner rank 4, as shown in Figure 1, are at a higher level than those of the outer rank 5, and the top of the cell I is stepped back at 6, immediately over the outer rank 5, so that all the jets 2 of both ranks are accessible through openings I in the side of the cell I. The cell is formed at the bottom with a space 8, 9 common to the filaments Ill coming from all the jets 2 and means, generally indicated at I I, are provided beneath the cell for collecting all said filaments in tow form.

In the preferred form of apparatus shown in the drawings, the filament-collecting means are in the form of a single tow-collecting device for collecting all the filaments in the form of a single tow I2. The filaments emerge all together from a common outlet l3 at the bottom of the cell, pass through guides I4, round a flanged guide pulley I5 and on to a large drum l6 driven at constant peripheral speed so as to draw the tow I2 out of the cell and deliver it into a coiler can I1 of the kind commonly employed in the collection of textile slivers.

In order to promote uniformity of the filaments III produced, asbetween the different jets 2 in the cell I it is of advantage to divide the cell, for the upper part of its length, into sub-cells 20 all opening downwards into an undivided portion 8, 9 of the cell leading to the common outlet l3. For this purpose, and for general convenience in construction, the preferred spinning cell shown is made of square or rectangular crosssection; such a cell can readily be divided by sheet metal partitions as at 2! to form two or more concentric ranks of approximately square compartments 28 each containing a single jet 2. Cells of other than square or rectangular crosssection may be used, however, e. g. of hexagonal or octagonal cross-section, and the upper parts thereof can be divided into sub-cells of rectangular or other suitable shape.

The subdivision of the upper part of the cell in the manner described above is of particular advantage when the setting of the filaments I 0 is effected by the evaporation of a volatile solvent therefrom, in which case the character of the filaments, and especially the shape of their crosssection, is liable to be affected by small differences in the evaporative conditions obtaining in the very early stages of setting. Dividing the upper part of the cell i into sub-cells 20 reduces the likelihood of the different jets 2 receiving substantially different supplies of the gaseous setting medium, serving in this instance as an evaporative medium to carry off the solvent vapours from the filaments, and prevents the setting me dium that acts on the group of filaments ii? emerging from one jet 2 being already laden with solvent vapour through having been in contact with the filaments of another jet. Where setting is effected otherwise than by the evaporation of volatile so;vent from the filaments iii, e. g. by mere cooling of the filaments, the subdivision of the cell is advantageous as preventing cross draughts of setting medium in the top of the cell which are apt to have a harmlul effect on the filaments in the early stages of their setting.

For the same purpose of promoting uniformity, each separate jet 2 can be supplied with filmiorming liquid by its own individual measuring pump so that the total denier of the filaments from each jet is held constant. Alternatively, however, the jets in the cell may be divided into greater or smaller groups, each group being fed from a measuring pump common to all the jets of that group. The several measuring pumps, whether for-the supply 01" individual ets or of groups of jets, are preferably disposed outside the cell in a compact battery (not shown) conveniently situated near the top of the cell. The filters (not shown) employed for filtering the liquid supplied to individual jets or groups of jets are preferably disposed close to the pumps so as to reduce as far as possible the complication of the arrangements in the top of the cell itself.

The jets can be supplied from the pumps and filters by pipes 23 proceeding from the battery of pumps and entering the cell by a central space 3 in the top of the cell, free of spinning jets and enclosed by the inmost rank 4 of jets 2. The pipes 23 serving the outer rank 5 of jets 2 pass through passages 23 (Fig. 2) formed in the partitions 2i dividing the subcells of the inner rank 3 from one another.

If it is desirable that the liquid extruded from the jets should be hot, as is the case when the film-forming liquid is a solution of cellulose acetate in acetone and is spun into a current of cold air moving in the same direction as the filaments and serving as an evaporative medium, it can be heated by the provision of a steam coil 25, or other heating means, disposed in the central space 3 in the top of the cell by which the pipes 23 supplying the jets 2 enter the cell. The top of the cell l is provided with heavy lagging 26 to retain the heat in thhe central space 3, and the length of run of the pipes 23 through this space is relied on to enable the film-forming liquid passing through them to be heated to the required degree. This provides an extremely economical method of heating. Alternatively, however, the liquid can be heated by immersing the pumps, and/or the filters, in the heated baths or jackets. The pipes 23 leading from the filters to the jets 2, can also be jacketed and, where a single pump serves a group of jets, the temperature of the header supplying the several jets of each group can be maintained by running alongside it a, parallel pipe or passage through which is circulated a heating medium at an appropriate temperature.

The length of the spinning cell from the top to the common outlet [3 at the bottom depends on the nature of the filaments Ill and the action of the setting .medium thereon, and on the linear speed of spinnin and other spinning conditions. It may vary according to the circumstances, from less than 10 feet up to thirty feet or more. The cell should in any case be long enough for the filaments to be sufficiently set, by the time they reach the common outlet 13, not to stick to one another as they are brought into contact at the outlet, or in subsequent collection and storage. The division of the top of the cell into sub-cells 28 may extend down the cell to a distance of the order of two to five feet according to the total length or" the cell.

The common outlet l3 at the bottom of the spinning celli I is. preferably led into by causing the walls 2.! of the bottom part 9 of the cell to converge to a small area at 28 in which the outlet is provided. The bottom part 9 of the cell l is thus of the form of an inverted pyramid, whose apex is truncated to form the outlet area. In order to facilitate the passage of the filaments-l0 to the outlet area, the'convergence of the walls 2? is prei'eracly such that their angle to the horizontal is greater than the angle of repose of filaments resting thereon. In this way, the filaments It extruded from: the jets 2, falling vertically and striking the converging walls,2l, automatically find their Way to the outlet area 28 under gravity. The common outlet may be further reduced in area by providing a pair of swing doors 29 which can be opened to facilitate the initial emergence of the filaments, but subsequently closed so as to leave a reduced opening-l3. The guides ill can be in the form of forked guides mounted on the doors-253 so asto engage the filaments l8 and guide them into the form of a com pact tow l2 when the doors areclosecl. Springs 39 can be provided to hold thedoors 29 in the open or closed position. Windows 22' may be provided in the walls Zl for the illumination and inspectionof the inside of thecell.

The gaseous setting medium, contained with-' in the cell i for the purpose of setting the filaments ill after they are extruded, is preferably in the form of a current of air flowing in thedirection of the extrusion of the filaments Illand drawn off from the lower partoi' the-cell I. Thus, air may enter at the topof the cell through the openings which give access to the-spinning jetsZ or through suitable slots or other apertures. in access doors covering the said openings. f'he air passes down the cell and is withdrawn through a series of draw-oil pipes 31 disposed in an enlargement 32 of the cell i immediatelyabove the sharply tapered part e atthe bottom of the cell. The pipes 3| communicate with a suction duct 33 which extends round the cell and is connected by a duct 34 to a suction main: Openings may also be provided close to the outlet-at the bottom of the cell, as, at 35-, where there are shown gauze-covered openings,- one on each; wall 2? of the tapered part 9 of the cell, each opening 35 communicating with a common pipe 36., The pipe 38 has aconnection 3? by means ofjwhich air may be sucked off from, or additionalair introduced into, the neighbourhoed of the common outlet. By these means the taperedpartll can be continuously swept by-acurrent of air.

In order to reduce the volume of the -cell that is traversed by the. current of air drawn-off through the pipes 3!, the middle of the cell may be occupied by a closed shell '38, extending over the part 8 of the length of the cell, i. e. from the central space 3 at the top of the cell lto the level of the enlargementqEZ. The shell 38 isinot in communication with the, part. of the. cell l through which the filaments l pass, although, if desired, provision may be made for drawing 01f air centrally of the cell l by a suction pipe (not shown) extending up the middle of the shell 38.

The invention is of especial importance in relation to the spinning of filaments of cellulose acetate. It may, however, also be applied to the spinning of other film-forming materials capable of constituting the basis of a film-forming liquid that can be spun into filaments and set by the action on the filaments of a gaseous setting medium. Examples of other film-forming materials than cellulose acetate that can be used in solution in volatile solvent, are other esters and mixed esters of cellulose such as cellulose propionate, cellulose butyrate, cellulose acetate propionate and cellulose acetate stearate, and cellulose ethers such as ethyl and benzyl cellulose.

Having described my invention, what I desire to secure by Letters Patent is:

1. An apparatus for the production by dry spinning of a heavy bundle or tow of continuous filaments, said apparatus comprising a vertical spinning cell, a plurality of ranks of multi-orifice jets in the upper part of the cell, one rank within another, each rank consisting of a number of jets arranged round the middle of the cell, the jets of each inner rank being at a higher level than those of the rank immediately outside it, and the top of the cell being stepped back so that all the jets are accessible through openings in the sides of the cell, the cell being formed at the bottom with a space common tothe filaments from all said jets, and means for collecting all said filaments in tow form.

2. An apparatus for the production by dry Spinning of a heavy bundle or tow of continuous filaments, said apparatus comprising a vertical spinning cell, a number of multi-orifice jets in the upper part of the cell arranged round the middle of the cell in two ranks one within the other, the jets of the inner rank being at a, higher level than those of the outer rank, and the top of the cell being stepped back immediately over the outer rank so that all the jets of both ranks are accessible through openings in the side of the cell, the cell being formed at the bottom with a space common to the filaments from all said jets, and means for collecting all said filaments in tow form.

3. Apparatus according to claim 1, comprising a tow-collecting device for collecting the filaments from all the jets in the form of a single tow.

4. Apparatus according to claim 1, comprising partitions in the upper part of the cell, dividing said cell into sub-cells all opening downwards into the common space.

5. Apparatus according to claim 1 comprising a pair of doors disposed at the bottom of the cell to facilitate manipulation of the filaments, said doors, when closed, leaving a restricted outlet for the passage of the filaments.

6. Apparatus according to claim 1, wherein the bottom of the cell is in the form of an inverted pyramid whose apex is truncated to form an outlet for all the filaments.

'7. Apparatus according to claim 6 comprising principal suction means immediately above the inverted pyramid at the bottom of the cell and auxiliary means for the withdrawal or introduction of setting medium close to the truncated apex Of said pyramid.

8. Apparatus according to claim 1 comprising suctionmean's disposed nearthe bottom of the I cell for the withdrawal of gaseous setting medium from the cell.

9. Apparatus according to claim 1 comprising dope-heating means for heating the film-forming liquid to be extruded from the jets. 1

10. Apparatus according to claim 9, wherein the dope-heating meansare disposed in the top of the spinning cell within the area of the inner..- most rank of jets.

11. Apparatus according to claim9 comprising suction means disposed near. the bottom .of the cell for the withdrawal of gaseous setting medium from the cell.

12. Apparatus according to claim 1 comprising a closed inner shell, below and within the area of the innermost rank of jets, which is not in communication with the part of the cell through which the filaments pass.

13. Apparatus according to claim 12 comprising partitions in the upper part of the cell terminating part-way down the inner shell, dividing said cell into sub-cells all opening downwards into the common space surrounding said shell.

14. Apparatus according to claim 2 comprising partitions in the upper part of the cell, dividing said cell into sub-cells all opening downwards into the common space.

15. Apparatus according to claim 14 comprising suction means disposed near the bottom of the cell for the withdrawal of gaseous setting medium from the cell.

16. Apparatus according to claim 2 wherein the bottom of the cell is in the form, of an inverted pyramid whose apex is truncated to form an outlet for all the filaments, said outlet comprising a pair of doors to facilitate manipulation of the filaments, said doors, when closed, leaving a restricted outlet for the passage of the filaments.

17; Apparatus according to claim 2.. wherein the bottom of the cell is in the form of an inverted pyramid whose apex is truncated to form an outlet for all the filaments, said apparatus comprising principal suction means immediately above said inverted pyramid for the withdrawal of gaseous setting medium from the cell and auxiliary means for the withdrawal or introduction of setting medium close to the truncated apex of said pyramid.

18. Apparatus according to claim 2 comprising dope-heating means for heating the film-forming liquid to be extruded from the jets.

19. Apparatus according to claim 18 comprising suction means disposed near the bottom 01 the cell for the withdrawal of gaseous setting medium from the cell.

20. Apparatus according to claim 19 wherein the bottom of the cell is in the form of an inverted pyramid whose apex is truncated to form an outlet for all the filaments, said apparatus comprising principal suction means immediately above said inverted pyramid for the withdrawal of gaseous setting medium from the cell and auxiliary means for the withdrawal or introduction of setting medium close to the truncated apex of said pyramid.

21. Apparatus according to claim 20 wherein the dope-heating means are disposed in the top of the spinning cell within the area of the innermost rank of jets.

22. Apparatus according to claim 21 comprising a closed inner shell, below and within the area of the innermost rank of jets, which is not in communication with the part of the cell through whichthe filaments pass.

23. Apparatus according to claim .22 comprising partitions in the upper part of the cell, terminating part-waydown the inner shell, dividing said cell into sub-cells all opening downwards into the common spacezsurrounding said shell.

24;;Apparatus according to claim 23 comprising apair of "doors disposed at the bottom of the cell to facilitate manipulation of thefilaments, :said :d'oors, when closed, leaving a restricted outlet .for the passage of the filaments, and a towcollecting device for collecting, .in'the form of a single tow, the filaments from all the jets-emerg- "ing from said restricted outlet.

25. Apparatus according to claim 2 comprising a closed inner shell, below and within the area of the innermost rank of jets, which is not in communication with the part of the cell through whichithe'filaments pass.

WILLIAM IVAN TAYLOR.

No references cited.

Claims (1)

1. AN APPARATUS FOR THE PRODUCTION BY DRY SPINNING OF A HEAVY BUNDLE OR TOW OF CONTINUOUS FILAMENTS, SAID APPARATUS COMPRISING A VERTICAL SPINNING CELL, A PLURALITY OF RANKS OF MULTI-ORIFICE JETS IN THE UPPER PART OF THE CELL, ONE RANK WITHIN ANOTHER, EACH RANK CONSISTING OF A NUMBER OF JETS ARRANGED ROUND THE MIDDLE OF THE CELL, THE JETS OF EACH INNER RANK BEING AT A HIGHER LEVEL THAN THOSE OF THE RANK IMMEDIATELY OUTSIDE IT, AND THE TOP OF THE CELL BEING STEPPED BACK SO THAT ALL THE JETS ARE ACCESSIBLE THROUGH OPENINGS IN THE SIDES OF THE CELL, THE CELL BEING FORMED AT THE BOTTOM WITH A SPACE COMMON TO THE FILAMENTS FROM ALL SAID JETS, AND MEANS FOR COLLECTING ALL SAID FILAMENTS IN TOW FORM.

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