US2763892A - Spinning apparatus - Google Patents

Description

Sept. 25, 1956 G. E. Moos ET AL PINNING APPARATUS 2 Shets-Sheet 1 Filed April 16, 1952 lNVENTOR Sp GILBERT E. MOOS JOHN R.SHOUP S Y E N R m A Sept. 25, 1956 G. E. Moos EITAL 2,763,892

SPINNING APPARATUS Filed April 16, 1952 2 Sheets-Sheet 2 Tij. v

INVENTORS 7 6 /48:??? 5 "005 By Joy/v A? Jyoup United States Patent fiice SPINNING APPARATUS Gilbert E. Moos, Cumberland, and John R. Shoup, Cresaptown, Md., assignors to Celanese orporation of America, New York, N. Y., a corporation of Delaware Application April 16, 1952, Serial No. 282,582

8 Claims. (Cl. 18-8) This invention relates to spinning and relates more particularly to an improved process and apparatus for the spinning of filamentary materials by the dry spinning process.

In the production of artificial filamentary materials by the so-called dry-spinning process, a dope or solution of filament-forming material in a volatile solvent is pumped or otherwise forced through a spinning jet, containing at least one spinning aperture, into a spinning cabinet wherein it is brought into contact with an evaporative medium. In the spinning cabinet, the filamentary materials are set and the bulk of the solvent is evaporated therefrom, following which the filamentary materials are drawn from the spinning cabinet and may be wound into package form or otherwise treated. The evaporative medium, containing the solvent which has been evaporated from the filamentary materials, is passed from the spinning cabinet to a solvent recovery system wherein the solvent is recovered for further use.

The properties of the filamentary materials produced by this process will depend, among other things, on the relative velocity of the filamentary materials and evaporative medium flowing through the spinning cabinet and the temperature gradient along the length of the spinning cabinet. They are also dependent on the temperature of the evaporative medium when it first strikes the filamentary materials emerging from the spinning jet. A number of serious practical difiiculties are encountered when it is attempted to control all of these factors simultaneously to obtain filamentary materials having certain desired properties. For example, where filamentary materials of a certain denier are being spun successfully in a spinning cabinet of given size and it is desired to reduce the denier of the filamentary materials, no change is normally required in the velocity of the evaporative medium simply because of the change in denier. However, a smaller amount of solvent is evaporated fromthe filamentary materials of reduced denier. As a result, the evaporative medium leaving the spinning cabinet will have a low concentration of solvent vapors and the recovery of the said solvent vapors will not be economically feasible. On the other hand, if it is desired to increase the denier, difiiculties are encountered because the volume of evaporative medium is not sufiicient to remove the bulk of the solvent from the filamentary materials. Similar difficulties are encountered when it is desired either to increase or to reduce the spinning speed. Because of these difficulties, it has hitherto not been possible, with the use of a spinning cabinet of given dimensions, to carry out the production of filamentary materials of diflerent deniers and at various spinning speeds by the dry-spin ning process under optimum conditions to produce filamentary products having certain desirable properties.

It is an important object of this invention to provide a process and apparatus for the spinning of filamentary materials by the dry-spinning process which will be free from the foregoing and other difficulties.

Another object of this invention is to provide a process and apparatus for the production of filamentary materials by the dry-spinning process under optimum spinning conditions which will enable filamentary materials having a wide range of deniers to be spun at various spinning speeds in a spinning cabinet of given dimensions.

Other objects of this invention, together with certain details of construction and combinations of parts, will be apparent from the following detailed description and claims.

According to the present invention, there is provided a spinning cabinet which may comprise a length of cylindrical, rectangular or other tubing equipped with suitable means including a spinnerette for the spinning of a filamentary material. The spinning cabinet is connected at its ends so as to form part of a complete loop through which a stream of evaporative medium may be circulated by means of a suitable means, such as a fan or the like, the evaporative medium flowing through the spinning cabinet in the same direction as the filamentary materials. Means are provided for continuously withdrawing to a solvent recovery system a portion of the evaporative medium circulating through said loop and for introducing an equal amount of evaporative medium into said loop. By regulating the proportion of evaporative medium withdrawn from said stream it is possible to control the concentration of solvent vapors in the evaporative medium to a level where recovery thereof is most economical without imposing any restrictions on the velocity of the stream of evaporative medium, the denier or the filamentary materials being spun, the spinning speed, or the like.

A heat exchanger is positioned in the loop through which the evaporative medium circulates so that the temperature of the said medium may be brought to its optimum value before it enters the spinning cabinet and contacts the freshly formed filamentary materials. Likewise, the spinning cabinet is equipped with suitable heat ing means so that the temperature gradient along the length of the spinning cabinet may be brought to its optimum value.

In order for spinning to be carried on successfully with this system, particularly at high spinning speeds when the evaporative medium flows into and through the spinning cabinet at relatively high velocities, it is essential that substantially all turbulence be eliminated from the stream of evaporative medium entering the spinning cabinet. If the stream of evaporative medium entering the spinning cabinet and coming into contact with the freshly formed filamentary materials, which are in a relatively plastic state, has any appreciable degree of turbulence, it will have an undesirable effect on the properties of the filamentary materials. break the filamentary materials and interrupt the continuity of spinning. To remove substantially all the turbulence from the stream of evaporative medium entering the spinning cabinet, there is provided, at a point adjacent to the entrance of the spinning cabinet, a streamlining unit which will cause the evaporative medium to enter the spinning cabinet in a stream having substantially laminar flow. While a streamlining unit of any design can be used for this purpose, particularly advantageous results are obtained with a streamlining unit of the design disclosed in application Serial No. 257,472,

members positioned coaxially of the spinnerette and form-' ing an annular passageway through which the evaporative medium flows into the spinning cabinet.

have positioned between them a plurality of streamlining fins extending longitudinally thereof.

Further to reduce the development of turbulence in the fiatented Sept. 25, 195.6.

In certain cases, it may even These spaced. members are advantageously of frusto-conical shape and 3 stream of-evaporative medium entering the spinning cabinet and to eliminate or minimize-the effects of other irregularities in said stream, there is provided a manifold positioned immediately in advance of the streamlining unit-and from which the evaporative-medium ilowsinto.

the streamlining unit. The manifold comprises a chamber which 'acts as a stabilizing reservoir-tojreruove any small ir regularities in the pressure or rate of flow of'the evaporative medium. "The manifold also includes means for distributing the-evaporative medium in substantially equal quantities to all portions of the periphery of the streamlining unit whereby the efliciency of said unit in eliminating turbulence from the stream of evaporative medium is increased.

The process and "apparatus of this invention areparti'cula'i'ly "useful in the spinning of filamentary-materials by the dry spinning'pro'ces's atspinning speeds above about 600 meters perminute, as'measurediatthe poiut'where the "filamentary materials are withdrawn from the spinning'cabinet, and-with velocities of evaporative medium through the spinning cabinet above about 15 meters per minute since at these high spinning speeds'the difficulties outlined-above become especially pronounced.

Among the filament-forming materials that may be spun in this manner are the organic esters and others of cellulose such as, for example, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose acetate propionate and ethyl cellulose, as well as such filament-forming materials as polyvinyl chloride,

polyvinyl acetate, polyvinyl alcohol and polyacrylonitrile.

Volatile solvents in which these materials may .be dissolved include, for example, acetone, methylene chloride, methanol, water and dimethylformamide. Evaporative mediums that may be used include, for example, carbon dioxide, nitrogen and the like, but it is the general practice to use air for this purpose in'the interest of economy.

A preferred embodiment of this invention is shown diagrammatically in the accompanying drawing wherein,

Fig. 1 is aside elevation-al'view of the spinning apparatus,

Fig. 2is a cross-sectional view taken 'onthe line22 in Fig. 1 in the direction of the arrows,

Fig. 3 is a cross-sectional view,-on an enlarged scale, taken on the line 3.3.in Fig. 1 in the direction ofthe arrows, and

Fig. '4 is a cross-sectionalyiewirt elevation of the manifold and streamlining unit.

Referring now tothedrawing, the reference numeral 11 designates a .spinningcabinet which, as shown,'may comprise alength. of cylindrical tubing. The spinningcabin-et 11 is providedlwith a'heating-coil 12 which permits the temperature along the length of said cabinet to beamtrolled. 'The heating coil 12 may be constructed ofa plurality .of sections, each 'under separate control, to permit the temperature gradient along the length of the spinning cabinet 11 to'be controlled in any desired manner. Positioned atLth-e upper endof'the spinning cabinet 11 is astreamlining uuit,'indicated generally by reference 13,'whose structure and function will'be "described more fully hereinafter. A .candle filter dope; preheater '14, to which'spinningidqpe is supplied through a-cnduit'15,-is mounted in thestrearnliningunitlB. The candle filter dope preheater'14 carries a spinnerette 16 from which'the spinning dope emergesin'theform ofa yarn'17. After emerging from the spinnerette "16, 'the yarn .17 passes through .the spinning cabinetll where the-bulk er the volatile solvent is vevaporated 'therefromfand'thence'into a chamber 18 from whichit is drawn bymeansofafeed wheel 19'which directs the yarn to a take-npidevice v .(not shown) or any .other desired textile apparatus.

'The evaporative medium, which removesthe'bulkof the solventfrom the yarn 17, flows downwardly through thezspinning cabinet 11 and into the chamber 218finjthe same'direc'tion as'thetsaidyarn. ,ItI is thenjilrawnirom thechatnbervls througha conduit20 into .a'chamberil which acts as a waste catcher in the event that the yarn 17 breaks and pieces thereof are carried along in the stream of evaporative medium. From the chamber 21 the evaporative medium is drawn through a conduit 22, to a fan 23 and is forced by said fan through a conduit 24 and a heat exchanger 25 to the midpoint of a semicircular distributor 26 and into a manifold indicated generally as 27 from which it flows to the streamlining unit 13 and back to the spinning cabinet 11. The cross-sectional area of the two branches of the semicircular distributor 26 is equal to the cross-sectional area of the conduit 24-t0 avoid any changes in the pressure or velocity .of the. evaporative medium flowing therethrough. A heat transfer medium, such as steam, from any suitable source (not shown) is supplied to the heatexchanger .25 through a conduit 28 and is discharged from said heat exchanger through a conduit 29. The temperature of the evaporative medium leaving the heat exchanger 25 is controlled automatically by means of a thermostat 31 which-regulates avalve '32 in conduit 28 to increase or reduce the flow of steam through-the said heat exchanger.

A portion of the evaporative medium is continuously withdrawn from the conduit 22 through 'a conduit 33 to a solvent recovery system (not shown) where the solvent vapors present therein are recovered for further use. To control the amount of evaporative medium going to .the solvent recovery system, the conduit 33 is provided with a valve 34'and a plate orifice 35 and a pressure .gage 36 which act -to measure the flow of evaporative medium. The plate orifice 35 and pressure gage 3'6 may, if desired, bereplaced with any other type of flow measuringdevice, such as, 'for example,a flowmeter. 'The'evaporative medium which is withdrawn from the conduit 22 is replaced by an equal amount of evaporative medium which enters the system through a dust filter 37 and a conduit 38, which conduit is provided with a plate orifice 39 and a pressure gage 41 or other flow measuring device so that the quantity of evaporative medium flowing therethrough may be measured. The evaporative medium entering the system through the dust 'filter 37 may be the evaporative medium that has passed through the .solvent recovery system, or, when air is employed as .the evaporative medium, which .isgenerally the .case, may simply be atmospheric air. .Byregulating the amount ofevaporativc medium withdrawn through the conduit 33 to the solvent recovery system, it is possible to keep the concentration ofisolvent vapors .therein at any desired level while simultaneously imposing no limitations upon the velocity and temperature of the evaporative medium'flowing through the spinning cabinet 11. In this way,.it is possible to maintain optimum spinning conditions at all times, regardless of changes in the denier of the filamentarymaterials or. in

the spinning speed.

Substantially all the turbulence is eliminated fromthe stream of evaporativemedium, particularly at the point where'it comes intocontact with the newly formed yarn 17 emerging from the spinnerette 16, through the com- .b'iuedaction ofthe manifold 27 and the streamlining unit member 43 at alevel alittle above thebase plate jis 7 forms a stabilizing reservoir, whichserves to.even ,out

small variations in the pressure ,of the evaporative medium passingthrough the. manifold. T Because .of the construction and arrangement of the manifold 27, the evaporative medium is distributed uniformly to all portions of the annular opening 47. d

The streamlining unit 13 into which the evaporative medium flows from the manifold 27 comprises a cylindrical member 48 of a diameter equal to' the outer diameter of the annular opening 47 which is butted up against the said opening. Extending downwardly from the cylindrical member 48 is an upwardly tapered, frusto-conical member 49, the lower end of which is of the same diameter as the upper end of spinning cabinet 11 and which is butted against the said spinning cabinet and is connected thereto by means of a sleeve 51.' Supported internally and coaxially of the cylindrical member 48 and the frustoconical member 49 by means of a plurality of fins 52 is a member 53 which comprises an extension of the cylindrical member 43. The member 53 includes an upper cylindrical portion 54 which is coaxial with the cylindrical member 48 and forms with said member an annular passageway 55 and a lower inwardly tapered, frusto-conical portion 56' which is coaxial with the frusto-conical member 49 and forms with said member an annular passageway 57. Advantageously, the wall of the frusto-conical portion 56 is inclined at a somewhat steeper angle than the wall of the frusto-conical member 49 so that the crosssectional area of the annular passageway 57 remains substantially constant although its diameter decreases. As a result, there is no change in the velocity of the evaporative medium flowing through the annular passageway 57 and no tendency for turbulence to develop therein. In addition, the cross-sectional areas of the annular passageway 46, the annular opening 47, the annular passageway 55, and the spinning cabinet 11 are also equal to the cross-sectional area of the annular passageway 57 further to reduce the development of turbulence in the stream of evaporative medium. If desired, streamlining fins may also be provided in the annular passageway 55.

During operation, a stream of evaporative medium is caused to circulate continuously by means of the fan 23 through the system comprising the spinning cabinet 11, the chamber 18, the conduit 20, the chamber 21, the conduit 22, the conduit 24, the heat exchanger 25, the manifold 27 and the streamlining unit 13. The velocity of this stream of evaporative medium in the spinning cabinet 11 is brought to its optimum value for the denier of the particular yarn 17 being spun and the spinning speed being employed by adjusting the speed of the fan 23 or in any other suitable manner. Similarly, the temperature of the evaporative medium first striking the yarn 17 is brought to its optimum value by suitable adjustment of the thermostat 31 and the heat exchanger 25, while the temperature gradient along the length of the spinning cabinet is brought to its optimum value by suitable adjustment of the heating coil 12. A portion of the circulating stream of evaporative medium is Withdrawn continuously to a solvent recovery system through the conduit 33 While fresh evaporative medium is introduced into the said stream through the dust filter 37 and the conduit 38. The spinning cabinet 11 is so designed as to have suflicient evaporative medium flowing therethrough to remove the bulk of the solvent from the heaviest denier filamentary materials it is desired to spin therein. Then, when it is desired to spin filamentary materials of lower denier, it is simply necessary to recirculate a greater proportion of the evaporative medium to remove the bulk of the solvent from said materials while building up the solvent concentration in the evaporative medium to an economical level for recovery.

The spinning cabinet of this invention may also be used without recirculation of the evaporative medium where it is desired simply to control the temperature of the evaporative medium first striking the filamentary materials and the temperature gradient along the length of the spinning cabinet. In this case, a valve or other means may be provided in the conduit 22 between the conduit 33 and the, conduit 38, which valve when closed will interrupt the recirculation of the evaporative medium.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of our invention.

Having described our invention, what we desire to secure by Letters Patent is:

1. In an apparatus for the production of filamentary materials by the dry-spinning process, the combination with a spinnerette through which a solution of a filamentforming material in a volatile solvent is forced to form the filamentary materials, of a spinning cabinet through which the filamentary materials pass, means connected to the spinning cabinet to form a loop, means for causing a stream of evaporative medium to flow through said loop and said spinning cabinet whereby the evaporative me dium will remove the bulk of the solvent from said filamentary materials as they flow through said spinning cabinet, means for dividing the evaporative medium in said loop into a plurality of streams, a manifold having a plurality of inlets for receiving said plurality of streams, said manifold comprising a stabilizing chamber communicating with said inlets and positioned at the entrance to the spinning cabinet to remove irregularities in the flow of the evaporative medium and having an annular outlet for the flow of said medium from said stabilizing chamber to said spinning cabinet, means for withdrawing solvent-vapor-containing evaporative medium from said loop, and means for introducing solvent-vapor-freeevaporative medium into said loop.

2. Apparatus as set forth in claim 1 in which said manifold comprises a cylindrical shell, an inner co-axial cylindrical member, and an annular plate fastened to said cylindrical member and extending almost into contact with said shell, the space enclosed by said shell, said inner member and said plate forming said stabilizing chamber, said apparatus also including means passing through the interior of said inner member for delivering said solution of said filament-forming material to said spinnerette.

3. Apparatus as set forth in claim 1 in which said cham ber is annular and concentric with said annular outlet.

4. Apparatus as set forth in claim 3, said apparatus further comprising a streamlining unit having a tapered annular passageway for the flow of said medium from said annular outlet into said cabinet, said passageway being co-axial with said outlet, said chamber and said spinnerette.

5. Apparatus as set forth in claim 1 in which said manifold comprises a cylindrical shell, an inner co-axial cylindrical member, and an annular plate fastened to said cylindrical member and extending almost into contact with said shell, the space enclosed by said shell, said inner member and said plate forming said stabilizing chamber, said apparatus also including means passing through the interior of said inner member for delivering said solution of said filament-forming material to said spinnerette, said apparatus also including a streamlining unit for introducing the evaporative medium from said annular outlet into that portion of the spinning cabinet adjacent to said spinnerette as a stream having substantially laminar flow, said streamlining unit comprising a pair of spaced frustoconical members positioned co-axially of the spinnerette and forming an annular passageway through which the evaporative medium flows into the spinning cabinet, and a plurality of streamlining fins positioned between said frusto-conical members and extending longitudinally thereof.

6. Apparatus as set forth in claim 5, said apparatus further comprising a heat exchanger positioned in said loop to control the temperature of the evaporative medium prior to its entry into said means for dividing the evaporative medium into a plurality of streams, and heating means positioned along the length of said spinning cabinet to control the temperature gradient along said spinning cabinet.

azaaeaa 7.1a a apparatus for-th pro ct of filam nt ry materials by the .dry spinning process, the combination with aspinuerette through which a s l i n of a fil en forrning material in a volatile -,solvent is forced to form the-filamentary materials, of a spinning cabinet through which the filamentary materials pass, means connected to the. ends of said'spinnin g cabinet to form a loop, external of said cabinet, means for causing a stream of evaporative medium to flow through said loop and through substantially the Whole length of said spinning cabinet and in the same direction as said filamentary materials whereby the evaporati-ve medium will remove thebulk of thetsolventlfrom. s idfilamen ary materialsas th y o hr gh said spinning cabin means ,f r withdr ng so v ntvap rcntaining evaporative medium from said 10 9, mean .fQr in ro ucing rsqlven -vape tree l apo a v medium int aid 1 0p d wns ream ot the w thdr l o a solvent-vapor-containing eyaponati-ve medium from said loop, and means for dividing the 'evaporative medium in sai -1 pa plu ality ofstreamsaf er tthe-intr du tian therein of said .solvent-vapor-free evaporative medium, a

:8 manit lsl h i ap u a ity n etst or rec i in s P ali y o st a i sa d,man fo d c mp n a s zin chamber communicating with said inlets and positioned at the entrance .to'the spinning cabinet ,to remove irregularitie sin the flow o f the .evaporative medium and having an annular outlet {or the flow of said medium from said stabilizing chamber to said cabinet.

.8. Apparatus as set forth in claim 7 in which said chamber isannular, saidfipparatus further comprising a streamliningvunit havinga tapered annular passageway for the flow of said mediumirom-said annular outlet into said cabinet, said passageway being .co-axial with said outlet, saidchamber and said spinnerette.

Referencesflited in the file of this patent U ITED ST TES PA E

Images