US2782623A

US2782623A - Apparatus for treating continuous filamentary bundles

Info

Publication number: US2782623A
Application number: US254752A
Authority: US
Inventors: Elvin L Coe; William P Dooley
Original assignee: American Viscose Corp
Current assignee: Akzo Nobel UK PLC
Priority date: 1951-11-03
Filing date: 1951-11-03
Publication date: 1957-02-26
Anticipated expiration: 1974-02-26

Description

Feb. 26, 1957 E. cos ETAL APPARATUS FOR TREATING CONTINUOUS FILAMENTARY BUNDLES Filed Nov. 3, 1951 qw g INVENTORS. ELVIN L. COE WILL/AM P. DOQLEY I: w l

Elvin L. Coe, Nitro, and William P.

United States atent" APPARATUS non ranarnso CONTINUOUS FHLAMENTARY BUNDLES Dooley, South Charleston, WV. Va., assignors to-American Viscose Corporation, Philadelphia, Pa, a corporation of Delaware Application November 3, 1951, Serial No. 254,752 7 Claims. (Cl.'68-181) fromfreshly-coagulated bundles or tows of viscose filaments.

It is an object of the present-invention to provide an improved and highly efiicient apparatus for washing a continuous filamentary bundle. of freshly spun and coagulated and/ or regenerated viscose. It is another object to obtain the materials removed by a washing; treatment in'sufiicient concentration to render recovery-thereof practical. A more specific object is 'toprovide' an apparatus for re moving carbon disulfide andspinning bath chemicals from large continuous: bundles or tows of viscose rayonfilaments. -It is-still anotherjobject to provide-apparatus ,which is easily laced and "mechanically simple yet capable of being adapted to a variety of operating conditions to obtain or recover materials in concentrations or quantities which Warrant the practice of the invention. Other/objects, features and advantages of the invention .will be apparent from the following description and the drawing relating thereto in which:

Fig. lis a diagrammatic elevation of staple fiber making equipment;

Fig. 2 is a fragmentary section through arnodifieddevice for washing a filamentary bundle;

' Fig. 3 is a section along line 'IIl-III of Fig; 2;

Fig. 4'is a top view of a portion of the apparatusillustrated in Fig. 1;

Fig. 5 is a perspective ofthe guides; I Fig. 6 is a view illustrating a modifiedsystem for raising and lowering the cover for the apparatus;

Fig. 7 is atransverse vertical section-in elevation of -modified apparatus for treating a plurality of strands; and

Fig. 8 is a fragmentary section of the apparatus shown in Fig. 7 taken along line VIII-VIII.

According to this invention, gaseous liquidor particulate materials, and especiallycarbon disulfide, whichare carried by a'continuous running bundle ofcoagulated viscose filamentary material are removed'by passing the bundle along a sinuous path extending repeatedly into and out of a heated liquid bath closed ofi' from the atmosphere.

Stripping elements for engaging the bundle are positioned along the path immediately after or beyond each submerged portion of the path and serve to direct. the bundle out of the bath and to express the'bath liquid from the bundle. 'Guide elements are arranged to guide the tow so that the portions of the bundle supported above the bath are at least as long and preferably substantially longer than the submerged portions.

Fig. 1 shows diagrammatically an apparatusfonmaking staple fiber from viscose spinning solution. A filamentforming viscose solution is extruded from the spinnerets-S into a'liquid coagulant'6 such asan aqueoussolution in a tank 7. The small streams discharged from the spin- -tained; i. e. around C.

2 nerets are, immediately ,coagulated into bundlesof filainents which travel a predetermined distance-through the bath and passaround guides 9 to godets 1t). Comb-like guides 11 are supported adjacent and laterally to each godet to space. the laps of the yarn axially on the godet. Preferably two or more laps are provided to establish sufficient frictionalcontact with the godets to stretch the yarns or the tow constituted of the yarns. Each yarn is wound two ormore laps around, its respective godet 10 and guide 11- and then vpasses to a guide 12 to be joined with the yarns'discharged from other godets to become a portion of a single tow 14.

The tow 14 carries a substantial amount of the liquid coagulating bath containing sulfuric acid, sodium sulfate, and apolyvalent metal sulfate, such as that of zinc, .magnesium or the like besides by-products, including carbon disulfide, hydrogen sulfide, and other sulfur compounds. The towsis; supported, by means such as one or more 1 guides, 15 as it, passes toward a container or trough 17 provided with a cover 19. The tow 14 is drawn through the container 17 by driven take-up means such as the pair -of'rolls 21 and 22 which have axes of rotation canted with respect to each-other for advancing a plurality of Wraps extending around therollsin adirection lengthwise of their axes. Rolls 21 and 22 may have a higher linear peripheral speedthan godets 1% so that stretching of-the filaments occurs alongthe path of the tow extending between the godets and the take-up rolls. Thus, by such a system, the stretching of the filaments constituting the strand or tow 14 and the-stripping thereof may be conducted .simultaneously. Moreover, the tension required for stretching effectively. promotes stripping action as the tow compacts tightlyin passing over the-variousguide andstripping elementshereinafter described. The rolls 21 and 22 may feed the tow intoa conventional rotary staple cutterr23. The tow enters an axially-extending passage of the rotor24 and'through a radially-extending passageway tobe dischargedthrough a port 25 in the peripheryrofithe rotor and-thence cut by a knife 26 into fibersiwhichrfall into a vessel 27.

Thecontainerontrough 17 contains a liquid having a level- 30. 1 Inthe' preferred practice of this inventiomthe liquid is heated by any convenient-means, such as the manifolds 31; 32, and 33 which may comprise perforated sections-for introducing a heated gas or liquid. The

manifolds'3l,"32, 33 whether perforated or nohmay-be connected with a steam supply (not shown). Temperatures of 80 C. to 'C. may be used. Preferably, the temperature-used is as high as can be practically'main- Other liquid, which is supplied to container 17 through the inlet 34, may merely be vwater or-it may be a dilute aqueous solution of sulfuric acid, with or without small amounts of the same salts that are carried-into the container 17 by the, bundle 14. The

liquid may be preheated-before entering container 17 and it is preferably introduced and discharged from the container 17 countercurrent to the direction of movement of the tow'14 through the container. As shown, the liquid inlet 34 is provided at the end of the trough 17 and connected with thelip 37b of the channel 37, through which the tow 14 is discharged. Liquid outlet duct 35 is.connected with the lip, 37d through" which. the tow 14 enters the container. The duct 35is.utilized to. maintain a pre- 65 .ward direction and terminatingat the desired level (see Figs.v 2;andf4, foranother type of overflow duct). The liquid discharged fromduct 35 may besentto. a. system determined level in'the container by extending in an up- ,for recovering the. materialsv therein,v such as sulfuric acid, sodium sulfate, zinc. sulfate.v or the like.

.During,operatiomthetinterior of the container is sealed fromthe outer atmosphere by the lid 19, the lower edge of which extends entirely around the upper edge of the trough 17 exteriorly thereof and within the peripheral channel, gutter, or moat 37. Liquid is free to pass from within the trough 17 to the peripheral channel 37 through the lips 37b and 37d, but, if desired, additional apertures may be provided in the trough wall to permit liquid flow between the channel 37 and the interior of the trough 17. The four edges of the cover 19 extend, when positioned for operation, into and below the level of the liquid in the channel 37.

A plurality of guides 40 each having an upwardlyfacing surface or rounded edge for engaging the tow are supported within the trough 17 at spaced positions from end-to-end of the container. Another series of guides 41, each having a surface or rounded edge which faces downwardly for engagement with the tow, are supported by the cover in spaced relationship with each other. A guide 42 is also supported at each end of the cover 19. The

guides

41 and 42 depress the tow into the liquid when the cover has been lowered into position. The

- guides 40 carry the running tow above the surface of the liquid and the change in direction of the bundle about the first of these guides compacts the bundle and strips off the liquid carried out of the bath by the bundle. A plurality of guides 39, having downwardlyfacing tow-engaging surfaces, are supported by the cover and engage the tow along the portions of its path which extend between guides 40 above the liquid. Any suitable means may be employed for supporting the

guides

39 and 40 in their positions shown in Figure 1, but preferably adjustable means, as for example as described hereinafter in relation to guides shown in Figures 2 and 3, are utilized. The guides 39 are supported at suflicient height to avoid forcing the tow into the liquid and serve primarily to increase the efiectiveness with which liquid is stripped from the tow by the guides 40. As shown, the guides 39 are arranged in alternate positions with respect to the

other guides

41 and 42 supported by the cover 19.

The upwardly-facing guides 40 and the downwardlyfacing guides 41 and 42 are arranged preferably to produce at least two submerged sections and at least two unsubmerged sections of the tow, the latter being of at least as great a length as the submerged sections.

In connection with the present invention, it has been discovered that filament breakage can be avoided or greatly reduced and that higher strength yarns can be produced from a system involving at least two submerged sections of the filamentary bundle with at least the first submerged section followed by an unsubmerged section in which stripping is effected substantially immediately after the bundle leaves the submerged section. In order to accomplish these benefits and at the same time obtain a high recovery efiiciency for the length of the equipment used, the total length of the submerged sections should not exceed the total length of the immediately following unsubmerged sections in which stripping occurs. The ratio between the lengths of the submerged and unsubmerged sections may be between 1 to 1 and 1 to 8 and preferably in the ratio range between 1 to 3 and l to 5. In a specific instance, the system may be operated with three submerged sections, each having a length of two feet and followed by an unsubmerged section of nine feet in length, making a total length of thirty-three feet through which the filamentary bundle may pass at such a rate of speed as to give a total time of submergence between one and four seconds. It has been found that by stripping off excess liquid at the beginning of each unsubmerged section, it is not necessary to maintain the filamentary bundle under the liquid for a long period of time or over a great distance in order to obtain high efliciency of recovery at speeds up to 100 meters or more per minute. Because of this discovery, the length of immersion in the heated liquid can be greatly reduced with a consequent reduction in the resistance encountered 4 in pulling the bundle through the system. It appears that this accounts for the improved strength in the product and its substantial freedom from filament breakage.

Ducts

43 and 44 carried by the cover 19, are provided for conducting the vapors and gases which are discharged from the tow into the enclosed space above the liquid.

Ducts

43 and 44 may be subjected to suction by conventional pumps, condensers, or other means (not shown). The vapors removed, such as carbon disulfide and hydrogen sulfide, may be passed through means, such as a condenser, to recover the carbon disulfide and an alkaline medium to remove the hydrogen sulfide.

The tow is led into the trough 17 through the notch or lip 37d in the end wall 38 of the trough 17. This notch extends below the surface of the liquid so that the guide 42 depresses the tow below the level of the liquid as it enters the container. This arrangement for introducing the tow into the container has the further advantages of reducing the length of the trough and the amount of liquid needed for the bath, since the tow gets an initial immersion in the lip 37d as it enters the container. Another guide 42 depresses the tow under the surface of the liquid in the lip 37b as the tow leaves the container 17. A final stripping of the tow is accomplished by the stripping element 37a, supported above the liquid level of the lip 37b.

The liquid of the bath may be directed or circulated in a direction generally counter-current to the movement of the strand 14, to increase the effectiveness of the liquid in washing the strand. For example, baflies 46, 47 and 48, which extend transversely of the interior of the chamber, and from the bottom thereof almost to the level of the bath, may be provided as shown to assure the movement of liquid through the container in a countercurrent direction. These baffies prevent the development of adverse. currents, and permit the feeding of the bath liquid to the container at a minimum rate to obtain satisfactorily cleaned tow, with the wash liquid discharged from the container carrying a maximum concentration of suspended and dissolved materials of value.

Fig. 2 illustrates, in section, the details of a modified discharge duct construction which may be adopted at the tow entrance of the container 17, shown in Fig. 1.

In the apparatus of Fig. 2, the tow 14 passes through an open-topped duct 50 connected or joined with the end wall of the container 17a. The tow 14 is depressed under the surface 30a of the liquid by

guides

41a and 42a. The duct 50 terminates in a rounded edge or lip 51 over which the excess liquid is free to pass into a drain duct 54. The upwardly-facing guides 40a are supported in U-shaped brackets or holders 55 which may be attached to the side wall of the trough 17a by bolts 57 and wing nuts 58. The side portions of the holders 55 are slotted to permit the guides 40a to be individually adjusted to any desired position relative to the surface of the bath. As shown in Fig. 3, holders 60, similar to the holders 55, support the guides 41a in a downwardlyfacing position. The holders 60 are adjustably attached to the roof of the cover 19a by the brackets 62 and 63. As shown in Fig. 3, the cover 19a is supported on a hinge which pivots at 64 with respect to a stationary mounting 65 to aid in raising and lowering the cover. The cover may be counterbalanced in conventional manner by a counterweight acting on a cable 67 attached to the cover 19a by a bracket 68. The cover 19a is provided with one or more short exhaust ducts 43a which move with the cover 19a when opened, and are connected, as by flexible duct 43b, with suction generating apparatus (not shown).

The guide holders 55 and 60 of the apparatus shown in Figs. 2, 3 and 4 are adapted (as shown in cross section Z by Fig. 2) to receive guides of non-abrasive and corrosionresistant material, such as the guide 70 shown in Fig. 5.

This guide is provided with side projections 71 which prevent the tow from escaping laterally from the guide surspasms face 72 Satisfactory materials for ceramic materials, and synthetic sapphire. are merely pushed into retaining flanges 55' and 60 and are readily replaceable.

Fig. 6 shows a modified'system for supporting the cover 19c of such an enclosed system. As shown, the cover issuspended from a stationary overhead support 75 by a plurality of cables 73 (two being'shown) which pass over pulleys 76 and are counterweighed by weights 77.

The apparatus illustrated in Figs. 2 and 3 is especially adapted for the rapid lacing of the tow between the upwardly-facing guides supported in the'container 17a and the downwardly-facing guides supported by the cover 19a. The oppositely-facing guides are separated when the cover is lifted and once the tow extended over the upwardlyfacing guides,the cover is lowered into position, lacing the apparatus for use; However, under some operating conditions, an arrangement may be preferred whereby the cover may beraised or'lowered without disturbing the path of thetow during its movement through the appa'ratus, that is, the movement of the cover should not affect the position of the downwardly-facing guides, such as guides 39, 41'and42 of Fig. 1, of which the

guides

41 and 42 force the towbelow the level of the bath. This arrangement would'permit the passage'of the tow through the container along its normal operating path during operation for the bath without substantially interfering With the treatment of the tow, even though the cover is raised.

In Figs. 7 and 8, a modified apparatus is illustrated in which all guides for the

filamentary tows

80 and 81 are attached to a liquid container 82 independently of a cover 83. A pair of downwardly-facing

guides

85 and 86, positioned transversely of the container 82 to separately engage

tows

80 and 81, are mounted in a single holder 87, adjustably securedto a post 88 by a stud 89 passing through a vertical slot 90 in the post 88. The holder 87 is provided with a saddle portion 91 engaging the periph eral surface of the post to maintain the holder in a fixed horizontal alignment. A wing nut 93 is threaded onto the stud 89 and turned tightly against'a saddle washer92, securingthe holder 87in fixed position on the post 88.

The holder 97, for supporting the upwardly-facing guides 95 and 96ymay be similar to that just described with regard to the

guides

85 and 86, except that its position is inverted with respect to that of the holder 87. The holder 97 is supported by a slotted post 98, similar to the post '88 and spaced lengthwise therefrom. Gaseous material separated from the tow may be withdrawn from the region over the bath enclosed by the cover 83 through a plurality of conduits, such as conduit 99, which extends upwardly through the bottom of the container 82 with its open end disposed above the bath. The various ducts 99 are connected with a manifold ltl'which conducts such gaseous materials away from the apparatus.

Thus, the present invention provides a simple and practical apparatus for washing and separating impurities from a freshly-spun multi-filament strand, involving pass ing the strand over a path whichleads into and out of a countercurrent stream of liquid according to an arrangement not heretofore known and appreciated. The invention is especially adapted for cleaning bulky strands, such as those known as tows, which comprise many thousands of regenerated'cellulose filaments, and to collect the materials washed therefrom in sufiicient concentration to render the recovery thereof practical. Moreover, the processing system provided is completely closed, a feature which reduces materially the exposure of personnel to obnoxious'and toxic gases and 'liquids'which accompany the preparation of such strands or tows of regenerated cellulose or staple fiber manufactured therefrom, for the trade. A primary advantage of the present invention is, of course, the economical use of factory space and labor.

While preferred embodiments of the invention have The guides 70 of the holders forming guides70 are cemented andffuse'd aluminum oxide, glass, glazed been'shown and de'scribed;itis"to be understood that changes-and variations may be made without departing from thespirit and scope of the invention as' defined-in the appended claims.

We claim 1. An apparatus for treatinga continuous running filamentary bundle including a container having a bottom wall and a pair of longitudinal side walls between which said filamentary bundle is adapted to travel, a plurality of longitudinally spaced bafiies extending between said side walls and dividing said container into a number of individual compartments, means at one end of said con tainer for feeding liquid into said container to a level extending above the top portions of said bafiles, means at the end of said container opposite said liquid feed means for discharging liquid from said container, said liquidfeed and discharge means cooperating to maintain the liquid level'in said container at an approximately constant plane and providing a liquid flow in a countercurrent direction to thetravel of said filtmentar-ybundle, afirst and a second series of stationary guide'elements extending transversely of said container, said guide elements each having a surface adapted to engage with the filamentary bundle during'its travel 'through said container, means for supporting the guideelements of said first series with their bundleengagingsurfaces extending downwardly toward the container bottom wall and below the liquid level planejsaidguide elements of said'first series being spaced apart longitudinally of said container with at least one guide element extendinginto each of said compartments, saidsecond series of guide elements being supported by said container with their bundle engaging surfaces extending' in an upward direction away from the container bottom wall and above the liquid level plane, said guide elements of said second series being spaced apart longitudinally of said container with at least one guide element extending above each compartment intermediate the guide elements of said first series and adjacent the bafile located therebetween, and means for tensioning the filamentary bundle whereby; said first and second series of guide elements are adapted to cause the filamentary bundle to travel a sinuous path through said container with the guide-elements'of said first-series sequentially depressing the bundle within each of said compartments while the guide elements of said second series elevate the bundle above the liquid level plane and strip the excess liquid therefrom after each such bundle depression.

2. An apparatus as set forth in claim 1 wherein at least one pair of guide elements of said second series extend above each compartment intermediate the guide elements of said first series and adjacent the bafile located therebetween, and further including a third series of stationary guide elements each having a bundle engaging surface, means for supporting the guide elements of said third series with their bundle engaging surfaces extending downwardly toward said bottom wall to a position intermediate the liquid level plane and a plane passing through bundle engaging surfaces of the guide elements of said second series, said guide elements of said third series being spaced apart longitudinally of said container with at least one of said guide elements of said third series being disposed between each pair of guide elements of said second series.

3. An apparatus for treating a continuous running filamentary bundle including a container having a bottom Wall and a pair of longitudinal side walls between Which said filamentary bundle is adapted to travel, means at one end of said container for feeding liquid into said container, means at the end of said container opposite from said liquid feed means for discharging liquid from said container, said liquid feed and discharge means cooperating to maintain the liquid level in said container at an approximately constant plane and providing a liquid flow in a countercurrent direction to the travel of said filamentary bundle, a first and a second series of stationary guide elements extending transversely of said container, said guide elements each having a surface adapted to engage with the filamentary bundle during its travel through said container, support means carrying the guide elements of said first series in spaced apart relationship longitudinally of said container with their bundle engaging surfaces extending downwardly toward the container bottom wall and below the liquid level plane, said second series of guide elements being supported by said container with their bundle engaging surfaces extending in an upward direction away from the container bottom wall and above the liquid level plane, said guide elements of said second series being spaced apart longitudinally of said container with at least one guide element being disposed intermediate adjacent guide elements of said first series, means for tensioning the filamentary bundle during its travel through said container whereby the filamentary bundle is caused to travel a sinuous path through said container with the guide elements of said first series sequentially depressing the bundle below the liquid level plane while guide elements of said second series elevate the bundle above the liquid level plane and strip the excess liquid therefrom after each such bundle depression, and means for moving said first series of elements and its support means upwardly relative to said second series of elements and said container to facilitate lacing of the apparatus along a horizontal plane.

4. An apparatus as defined in claim 3 wherein at least one pair of guide elements of said second series is disposed between adjacent guide elements of said first series, and further including a third series of guide elements, each having a bundle engaging surface, said guide elements of said third series being carried by said support means with their bundle engaging surfaces extending downwardly toward said botttom wall to a position intermediate the liquid level plane and a plane passing through bundle engaging surfaces of the guide elements of said second series, said guide elements of said third series being spaced apart longitudinally of said container with at least one of said guide elements of said third series being disposed between each pair of guide elements of said second series.

5. An apparatus for treating a continuous running filamentary bundle, a container having a bottom wall and a pair of longitudinal side walls between which said filamentary bundle is adapted to travel, means at one end of said container for feeding liquid into said container, means at the end of said container opposite from said liquid feed means for discharging liquid from said container, said liquid feed and discharge means cooperating to maintain the liquid level in said container at an approximately constant plane and providing a liquid fiow in a countercurrent direction to the travel of said filamentary bundle, peripheral channel means carried by the side walls of said container and communicating with the interior of said container at a level below said liquid level plane, a cover adapted to be disposed over said container with portions thereof received within said peripheral means, said cover cooperating with said peripheral means to enclose the portion of said container above the liquid level from the atmosphere, a first and a second series of stationary guide elements extending transversely of said container, said guide elements each having a surface adapted to engage with the filamentary bundle during its travel through said container, support means carrying the guide elements of said first series in spaced apart relationship longitudinally of said container with their bundle engaging surfaces extending downwardly toward the container bottom wall and below the liquid level plane, said second series of guide elements being supported by said container with their bundle engaging surfaces extending in an upward direction away from the container bottom wall and above the liquid level plane, said guide elements'of said second series being spaced apart longitudinally of said container with at least one guide element being disposed intermediate adjacent guide elements of said first series, means for tensioning the filamentary bundle during its travel through said container whereby the filamentary bundle is caused to travel a sinuous path through said container with the guide elements of said first series sequentially depressing the bundle below the liquid level plane while guide elements of said second series elevate the bundle above the liquid level plane and strip the excess liquid therefrom after each such bundle depression.

6. An apparatus as described in claim 5, further including exhaust means for expelling gas and liquid vapors from the enclosed portion of said container above the liquid level plane.

7. An apparatus for treating a continuous running filamentary bundle including a container having a bottom wall and a pair of longitudinal side walls between which said filamentary bundle is adapted to travel, means at one end of said container for feeding liquid into said container, means at the end of said container opposite said liquid feed means for discharging liquid from said container,

said liquid feed and discharge means cooperating to maintain the liquid level in said container at an approximately constant'plane and providing a liquid flow in a countercurrent direction to the travel of said filamentary bundle, a first and a second series of stationary guide elements extending transversely of said container, said guide elements each having a surface adapted to engage with the filamentary bundle during its travel through said container, support means carrying the guide elements of said first series in spaced apart relationship longitudinally of said container with their bundle engaging surfaces extending downwardly toward the container bottom wall and below the liquid level plane, said second series of guide elements being supported by said container with their bundle engaging surfaces extending in an upward direction away from the container bottom wall and above the liquid level plane, said guide elements of said second series being spaced apart longitudinally of said container with at least one guide element being disposed intermediate adjacent guide elements of said first series, means for tensioning the filamentary bundle during its travel through said container whereby the filamentary bundle is caused to travel a sinuous path through said container with the guide ele ments of said first series sequentially depressing the bundle below the liquid level plane while guide elements of said second series elevate the bundle above the liquid level plane and strip the excess liquid therefrom after each such bundle depression.

References Cited in the file of this patent UNITED STATES PATENTS 608,194 Greenwood Aug. 2, 1898 2,209,950 Nai Aug. 6, 1940 2,315,604 Ebert Apr. 6, 1943 2,494,468 Borzykowski Jan. 10, 1950 2,516,268 Spalding July 25, 1950 2,539,947 De Klerk Jan. 30, 1951 2,587,619 Hofmann Mar. 4, 1952 2,638,765 Quinn May 19, 1953 2,641,121 Belcher June 9, 1953 FOREIGN PATENTS 463 France of 1845 56,113 Netherlands Apr. 15, 1944