US2302908A - Method of drying thread or the like - Google Patents

Description

Nov. 24, 1942. s FRYER ETAL 2,302,908

METHOD OF DRYING THREAD OR THE LIKE Filed Sept. 28, 1939 4 Sheets- Sheet 1 W\ U q Summers Z6 ou|s s. FRYER EMERSON B. HELM KENNETH M. McLELLAN BY iztomcg Nov. 24, 1942- s. FRYER ET-AL 2,302,908

I METHOD DRYING THREAD OR THE LIKE Filed Sept. 28, 1933 4 Sheets-Sheet 2- Jnoenfors LOUIS S. FRYER EMERSON B- HELM AND KENNETH M. McLELLAN Nov. 24, 1942. L, FRY R HAL 2,302,908

METHOD OF DRYING THREAD OR THE LIKE Filed Sept. 28, 1939 4 Sheets-Sheet 3 3 nuemors LOUIS S. FRYER EMERSON B. HELM AND BY KEZNETH M- McLELLAN fix i ittrney L. s. FRYER ETAL METHOD OF DRYING THREAD OR THE LIKE Nov. 24, 1942.

Filed Sept. 28, 1939 4 Sheets-Sheet 4 m D m Q m m Q a a a a a \\m and s w m. .Q. MHM. m Q mvR Q FQMM... 1 v 1 1 I, I. D N a 6? w 1 i UEN/ 8 Q wm IN a W v "a K R R R 5 m x NR x Nu m. N D R 9 ML 4 Q Q N R SE mum Na .QRQ QR 8%. w #8 5w n i d w m 6 Q l HQ J mm 3v m? R. MM QM gm 7 QR 6% m 6R. 8h Q mm 8% M 6 m Patented av. 24, 1942 STATES P and Kenneth M. McLe llan, Lakewood, Ohio,

assignors to Industrial Rayon Corporation, Cleveland, Ohio, a corporation of Delaware Application September 28, 1939, Serial No. 296,930'

. 4' Claims.

This invention relates to methods which may be used in manufacturing and/or processing strip material such as threador the like (hereinafter referred to as thread). More particularly, the invention is directed to methods which may be employed advantageously in the manufacture and/or processing of textile thread to control certain of the physical and physico-chemical properties thereof; e. g., shrinkage, dyeing and other characteristics. The invention is especially useful in the manufacture by a continuous process of multiple filament artificial silk thread; i. e., rayon.

The use to which a completed commercial textile thread is ultimately to be put is determinative of the nature of the physical and physicochemical properties imparted to the thread. Such properties are influenced largely by the type of treatment employed in the processing of the thread.- For example, a textile thread, to be commercially acceptable for general use in the weaving industry, must almost always possess a low residual shrinkage capacity. The term residual shrinkage capacity, as used hereinafter, is defined as the amount by which a dry, finished thread will shrink, if unrestrained in any manner, upon being rewet and redried.

Commercial textile thread employed'in weaving, particularly for use as a weft thread, should be of such low residual shrinkage capacity as to preclude the possibility that the fabric woven therefrom will shrink by more than a very small amount, if at all, during the subsequent finishing operations. The finishing operations ordinarily consist of w ne. dyeing, etc., after which the fabric is usually dried in rigid tentering frames which hold the fabric to the desired finished width. If the residual shrinkage capacity of the thread from which the fabric is woven exceeds very low limits, the tendency of the fabric to shrink stresses the thread, causing barr effects to develop in the fabric and in some cases causing the fabric to 'be torn from the tenteringframes. In either case, the commercial value of the fabric is seriously impaired.

Furthermore, weaving thread should have throughout its length a uniform, and preferably high; afllnity for dyestuffs. Uniformity of dye affinity is important inasmuch as a woven fabric formed of thread which does not possess the desired uniformity usually embodies defects of the type known to the trade as shiners or dye barre which deleteriously afiect the commercial acceptability of the fabric. produce a thread having high dye affinity be- It is desirable to' sodium cellulose xanthate (viscose). Coagulation is brought about by extruding the solution through a plurality of minute orifices into an. acid precipitating bath, an operation which gives rise to a delicate thread consisting of a plurality of filaments that, at least at this stage, are more or less gelatinous in nature. Subsequent to coagulation, the thread is ordinarily subjected before it is initially dried to suitable processing treatments including washing, desulphurizing, etc. During these operations and in fact until such time as it is completely solidified and dried, the thread is usuallyconsidered to be in a gel state.

Great care must be exercised in processing thread while it-is in the gel state inasmuch as its physico-chemical properties are markedly affected by the nature of the processing treatments, as well as by the manner in which the treatments are administered to the thread. It has been found, for example, that the manner of drying the thread initially; i. e., from the gel state, determines to a large extent the final char acteristicsof the finished thread, particularly its dyeing properties. This is equally true whether the thread ismanufactured by the so-called continuous process or according to the discontinuous methods of producaion by which, until recently, all viscose artificial silk thread was produced.

' Among other things, the tension imparted to the thread during its drying from the gel state affects the physico-chemical characteristics of the thread. For example, if thread is dried in the spool package in which it is collected in the spool-spinning process, uneven dyeing properties result. Such non-uniformity results from the fact that shrinkage of the innermost layers of thread is prevented by the presence of the spool, while the faster drying outer layers of thread are prevented from shrinking only by the slower drying intermediate layers. Different portions of the thread are differently stressed, resulting in widely varying dyeaflinities. As a rule, such irre ularities render spool-dried thread unfit for capacity taken to improve its uniformity.

To overcome these difficulties, it has been. the

usual practice in the manufacture of weaving thread by discontinuous processes .to dry the thread in the form of a skein containing several thousand yards of thread; The skeins are usually formed by unwinding the thread from the package in which it was collected and rewinding it into skein form, in which state the thread can be supported so that it hangs substantially freeof tension during drying. The thread can therefore shrink freely, wherefore it has a low residual capacity to shrink; however, even such skein-dried thread does not have absolute uniformity, this for the ireason that the outer windings ofthe thread in the skein tend to dry more rapidly than the intermediate windings and therefore subject the thread to tension differences which affect its dye aflinity.

On the whole, the discontinuous production of viscose weaving thread is unsatisfactory because of the high cost of production, the waste of the thread due to injuries resulting from repeated handling, and the long periods of time required in processing. The completed product does not possess the desired uniformity of shrinkage, dye:-

ing and other characteristics; so that in general it is not capable of measuring up to the extremely hi h standard of-quality which. is desired. For such reasons, to, produce viscose. weaving thread commerciall 'by'a continuous. process wherein 'such disadvantages 'are eliminated has long been recognized as a desideratum. However, the continuous production; of viscose artificial silk thread involves other problems not present in discontinuous methods of 'production. Such problems arise primarily ,out of the fact However, the present invention, in addition to obviating the numerous disadvantages of the discontinuous process, gives rise to a thread which is eminently suitable for weaving, which is of a particularly high degree of uniformity of physical and physico-chemical characteristics, and which is characterized by a permanently low residual shrinkage capacity. The invention makes these results possible by repeatedly drying and rewetting the thread in a continuous process while permitting it to shrink under predetermined conv ditions, all as more fully explained hereinafter. For convenience the invention will be described as applied to the manufacture of multiple filament viscose artificial silk thread on apparatus operating on the principle of thatshown, de-- scribed and claimed in Knebusch et. al. Patent v In the drawings, Figure 1 represents a sectional elevation of one form of apparatus in which the invention is embodied. Figure 2, whichrepresents a portion of the apparatus of Figure l on an enlarged scale, shows the means for repeatedly wetting and drying the thread according to the invention. Figure 3 illustrates on the same enlarged scale a similar portion of modified apparatus likewise embodying the invention. Figure 4 is an end elevation of one form of thread- -advancing reel employed to dry the thread. Figure 5 represents a sectional elevation of said reel from line 55 of Figure 4.- Figure 6 is a sectional elevation of another type of threadthat in the continuous process thread in the finished state is produced from liquid viscose in a very small fraction of the time required in dis.- continuous p.ocesses. Whereas in discontinuous; processes thousands of yards of thread wound' in a package are subjected to for many hours or even days, process not more than a few yards of thread are subjected to a given set of processing conditions simultaneously. In particular, the shortness of the time available for the initial drying of the thread from the gel state is a factor causing difficulties in the manufacture of thread by a continuous process.

,In the continuous process of manufacture, it has been found that the rapid initial drying of .the thread from the gel state does not give rise to a permanently low shrinkage capacity, this even if the thread is permitted to shrink during such drying'operation. The residual shrinkage of thread dried under such conditions is often .so high that the thread is not well adapted to weaving on looms producing fabrics of widths approximating the intended finished width of the fabric. This difiiculty is probably related to the fact that in the continuous process the thread is dried in only a few seconds or, at the most, a minute or two. Such difliculties are not found in the manufacture of weavingifim' ead by discontinuous processes.

It has therefore been continuous process constitutes a very great improvementoverthe discontinuous processes iii thought that, while the};

" cose from a spinneret 2 disposed in a coagulating.

processingconditions in the continuous advancing reel employed to dry threadafter intermediate rewetting.

- Figure 1 shows a complete machine for continuously manufacturing multiple filament viscose artificial silk thread of low residual shrinkage capacity in accordance with the teachings of thepresent invention. Said apparatus, a portion of which is shown in greater detail in Figure 2, is adapted to produce a large number of threads simultaneously, each by the extrusion of visbath 3 contained in trough 4. Each thread 1 passes to a thread-advancing reel 5, the same being the first of a concatenate series of threadadvancingreels designated 5 to H, inclusive.

. In the apparatus of Figures 1 and 2, the threadadvancing reels 5 to 14, inclusive, take the form of reels of cantilever construction operating on the' principle of that described in said Patent -2,225,643. Each of the reels 5 to [4, inclusive,

advances the thread toward the unsupported end 7 thereof in a large number of closely spaced, generally'h'elical turns. Onisaid reels suitable liquid processing operations such as washing, desul phurizing, etc., are performed on the thread,

, after which the thread is dried. From the last reel M, the thread passes to suitable collecting apparatus, such as the cap-twister |5,'Whi0h collects the finished thread ill package form.

. In said apparatus, each thread-producing unit comprises a'spinneret, a descending series of reels 5 to, inclusive, and an associated cap-twister.

The reels in each descending series are disposed in stepped arrangement with the unsupported or discharge end of each preceding reel in opposite relation. to the supported or receiving end of the succeeding reel, the unsupported ends of all reels extending inthe same direction. A plurality of such thread-producing units is disposed on each side of the apparatus; so that the apparatus as a whole has two operating faces, one on each side thereof. Corresponding parts of all units on each s de of the apparatus are therefore in correspondmg positions a wise thereof.

The use to which the finished thread is to be put is largely determinative of the nature of the processing treatments and the manner of administering the treatments to each of the threads I. In the illustrated apparatus, the thread I is drawn upward by reel 5, on which a relatively long length of the thread is continuously but temporarily stored in order to provide suificient time for the thread to achieve the desired degree of coagulation before it is subjected to subsequent processing treatments. The thread then passes from the unsupported end of reel to the supported end of succeeding reel 6.

On reel 8, the thread may, if desired, be subjected to the action of an additional coagulating liquid. Wash water may next be applied to the thread on reel I, after which any free sulphur which may be produced in the thread as a result of the regeneration process may be removed by the application to the thread on reel 3 of a suitable desulphurizing liquid. The thread may be washed again on reel 9 to free it of the desulphurizing medium and, if desired, may be bleached on reel III. The thread I then passes to reel II on which it may again be washed.

In the embodiment of the invention illustrated in Figures 1 and 2, the liquid to the action of which the thread is subjected on reel 6 is supplied from a reagent distributor I'I communicating with a supply pipe I8 which extends 1on7 gitudinally of the apparatus on each side thereof. Similarly, the liquid supplied to each of the succeeding reels 'I to II, inclusive, is applied to the thread from a reagent distributor I'I communicating with a conduit I9 which extends longitudinally of the machine, being formed integrally with the lower portion of collecting trough 2I disposed beneath the preceding reel. Collecting troughs M are disposed beneath all the reels. from which "liquid drips from the thread, such liquid being recirculated and reused.

The various processing liquids are applied to the thread on reels 6 to I I, inclusive, at the unsupported end of each reel in such manner as to form a travelling film of liquid extending uninterruptedly around the entire thread-bearing periphery of the reel. In the illustrated appa- .ratus, the reels are inclined to the horizontal in order that such film of liquid may travel along each reel from the-unsupported end toward the supported end thereof, thus providing a countercurrent flow of liquid which more effectively processes the thread. Although these condi tions'do not occur on reels I2 and I3, it is con-. venient from a constructional standpoint to tilt them also. According to the present invention, after the aforementioned treatments have been performed, the thread is dried on reels-I2, I3 and I4, as explained hereinafter.

After threadI-has been completely processed, it is passed from the last reel I4 to cap-twister 16 by means of which it is twisted and collected. The collecting apparatus comprises a continuous belt 22, driven by rotating drum 23, which belt, guided by suitable pulleys, passes around the whirls 24 of cap-twisters IS on opposite sides of the apparatus, thus rotating the bobbins 25 and claimed in Bergmann et a1. Patent 2,203,665.

According to the invention, thread which has been formed as above described but which is still in the gel state is subjected to repeated drying with intermediate rewetting on a plurality of reels under conditions permitting shrinkage of the thread in the course of at least one drying operation. During the time that the various liquid processing treatments are being administered to the thread on the reels prior to reel I2, the thread is always in the gel state. On reel I2, however, the thread is subjected to its initial drying operation, being dried by means of heat applied 'to the reel from the interior thereof. After being dried on reel I2, it is rewet, stored under conditions such that excess liquid carried by the thread may drip therefrom on reel I3, and dried once again on reel I l.

While various modifications thereof may be employed, the apparatus shown in Figure 2 has been found to be extremely satisfactory for these purposes.

In said apparatus, each of the drying reels I2 and It is formed of metal, being heated internally thereof by the means hereinafter described. The thread passing'from reel II to reel I2 is substantially completely dried on reel I2, but just before it leaves said reel at the unsupported end thereof it is subjected to the action of a small stream of an aqueous rewetting liquid supplied from reagent distributor 29.

The liquid thus applied to the reel is not sufiicient in amount to spread over the reel but only to wet the last few turns of thread on the reel; however, the amount of liquid is suflicient to wet the thread thoroughly. The wet thread then passes to the reel I3 which, in the embodiment of the invention illustrated in Figure 2, constitutes a drip reel.

No processing medium is applied to the thread on reel I3; instead, the liquid applied to the thread just before it leaves reel I2 is permitted to drip therefrom. In view of the length of thread which is stored in this manner, drops of excess moisture carried by diflferen't portions of Y the thread which would otherwise tend to immounted on the whirls of such cap-twisters.

' Such cap-twisting apparatus forms no part of v the present invention, but is shown, described pair the uniformity of the subsequent drying operation may be removed by simply permitting them to drip from the thread. A mild evaporative action also takes place due to the exposure of the thread to the air. Consequently, when the thread reaches the discharge end of reel I3, all portions of the thread have the same or substantially the same moisture content.

The thread passing to reel I4, having a substantially uniform moisture content, may be uniformly dried on reel I4 provided that uniform drying conditions are applied to the thread. To aid in maintaining uniformity of drying conditions, an enclosure 30 is provided surrounding each reel I4. Said enclosure comprises a stationary portion 3| and a hinged closure por-' tion 32. Slots 33 and 34 are provided at the junctions of the hinged and stationary portions to permit the thread I to enter and leave said chamber in passing to and from reel I4. If desired, a similar enclosure may, of course, be pro-. vided for reel I2.

Among other things, the invention contemplates that shrinkage of the thread shall be permitted to take place as hereinafter described for the purpose, for example, of imparting the desired low residual shrinkage capacity .to the thread.

During the initial drying of the thread-on reel I! a certain amount of shrinkage tends to occur in the thread. It has been found advantrolled shrinkage of the thread in this manner,

the dye aflinity of the thread is favorably influenced, the thread dyeing somewhat darker than otherwise would be the case.

It has been found that a slight elongation of the thread occurs when it is rewet. In the apparatus illustrated, this is compensated for by rotating the reel i3, to which the thread passes after it leaves reel H, at a peripheral speed sufiiciently greater than that of the discharge end of reel i2. With that in mind, reels i2 and iii are rotated at the same angular speeds, but the diameter of reel [3 at its supported end is slightly larger than that of reel l2 at its un-' supported end. Preferably, the ratio of the diameters is such that neither tension nor slack is developed in the thread passing from reel i2 to-reel IS. The same eifect may, of couse, be

obtained with reels of equal diameters by. imposing a suitable difference on the angular velocities of the reels.

vNo appreciable shrinkage of the thread occurs while it is stored on reel l3; conrequently, reel i3 may be formed with no variation in the diameter thereof.

Re'el I4, however, is preferably provided with a contour of a character such that as the thread dries it may shrink freely. This is accomplished by forming the periphery of the reel so that it conforms closely to the shape of the diminishing helix which thethread tends to develop as it shrinks. It is known, for example, that the thread does" not begin to shrink as soon as it comes into contact with reel I4, wherefore the reel may, as shown, he made substantially cylindrical for a considerable portion thereof.

During this portion of the drying operation, external moisture only is being removed from 'the thread, the removal of which does not result in shrinkage of the thread.

Thereafter the internal moisture is removed,

' which results in marked shrinkage of the thread;

accordingly, the reel I4 is tapered over the intermediate portion thereof. The minimum diameter of the tapered portion of the reel is. such that suf cientshrinkage is permitted by the'time the thread reaches the end of the tapered portion to impart to the thread the desired low residual shrinkage capacity. If desired, the tapered portion of the reel may be so formed that the dried thread has virtually no residual shrinkage capacity whatsoever.

1 The final portion of the reel, which is of substantially cylindrical form, serves among other things. to insure substantially equal drying of the thread throughout its length. For example. portions of the thread which have not been as completely dried as other portions are enabled to complete their drying on such cylindrical'portion before they leave the reel. In general, it is desirable that the thread leaving this portion of the reel have a final moisture content in the neighborhood of 10%, more particularly since a moisture content of this order, especially at elevated temperatures, greatly facilitates twisting the thread. I

Reel H, as also reel I2, may advantageously have a contour conforming generally to that shown and described in Kline et al. Patent 2,203,686. The reel of said patent is so designed that the diameter of the reel in effect diminishes in the direction of travel of the thread more rapidly than the diameters of the thread turns tend to diminish as a result of shrinkage of the thread. Consequently, substantially un restrained shrinkage of the thread is possible in spite of unintentional variations which sometimes occur in the intensity of the drying conditions to which the thread is subjected on the reel.

The apparatus as a whole may be so designed that little, if any, tension exists in the thread during the various drying, rewetting and redrying operations, such slight tension as happens to be present being substantially constant. This may be accomplished by relating the peripheral speeds of the various reels so that although slack due to elongation is taken up, no stretch is imparted to the thread. However, the amount of tension to which the thread is subjected and the amount of shrinkage permitted in the thread during the first drying operation; 1. e., while it is being dried on' reel H, has little efiect upon' 'the residual shrinkage capacity of the thread.

The features thus far described form the subject matter of Kline et al. Patent 2,286,213.

The present invention includes a further feature which is'extremely useful in producing low residual shrinkage capacities in thread which is being dried continuously; namely, maintaining the thread for asubstantial period of time at high temperatures under conditions of high moisture content. By such means, what may be called a cooking effect is imparted to the thread. This step of saturating the thread with liquid while at a high temperature apparently plays.

an important part in the re-orientation of the micellar structure of the thread necessary to obtain substantially complete shrinkage thereof at the high drying speeds employed in the con-' tinuous processing of thread. Best results are obtained if the thread is subjected to a cooking operation immediately after the initial drying of the thread, preferably before the thread has had time to cool aPDIeciably.

In the embodiment of the invention illustrated in Figures 1 and 2, a pronounced cooking effect is produced at the unsupported end of reel l2: at that point,.an aqueous rewetting liquid is applied to the thread while the threadis still I at the relatively high temperature of the reel.

To aid in thec'ooking effect, a higher temperature is employed'on reel l2 than on reel ll: indeed, it has been found desirable to maintain the temperature- 0f reel l2 considerably above the boiling point of the rewetti-ng liquid; 1. e.,

at a temperature in excess of 100 C. It has also been found desirable to maintain the temperature on reel H below the boiling point of the rewetting liquid, since this permits a more nearly complete shrinkage of the thread. The rewetting liquid may be either cold or-ho x but,

in accordance with the practicof this in '1- tion,- is preferably employed after being 1. st

heated to a temperature approaching the point of water.

boiling While the embodiment of the invention, shown in Figures 1 and 2 is preferred,apparatus embodying'the inventionin modified form may also be employed. Thus in Figure 3, which repre sents abortion of a continuous processing apparatus generally similar to that shown in Figure 2, the rewetting liquid is not applied to the thread on the reel 2, but is applied to the thread after it leaves said reel. More specifically, the rewetting liquid is applied to' the first few turns of thread on reel 3. It is applied by means of a reagent distributor 29a supplied fram 'a conduit I9 forming part of the trough 24 disposed below the preceding reel. The remainder of reel l3, on which portion no liquid of any kind is applied to the thread, serves as a drip stage fore equalizing the moisture content of the thread, precisely as has been explained above in connection with reel l3 of Figure 2.

The rewetting liquid applied to the thread on reel i3 may be at room temperature but preferably is heated, since this produces a cooking effect generally similar to that produced at the unsupported end of reel l2 in the embodiment of the invention shown in Figure 2. However, somewhat better results are obtained when the rewetting liquid is applied to the thread while the thread itself is heated. In the embodiment of Figure 3, the reel I2 is shown as having no taper to compensate for the tendency of the thread to shrink, each reel member being substantially cylindrical in form. As has been ex- A bolt 45, holding a washer 46 against the outer sealing member 43 at the unsupported end of the reel, is threaded into a plug 41 welded in the unsupported end of hollow shaft 31. A washer 48, -disposed on shaft 31 as by means of the snap ring 49 shown, bears against the outer sealing member 53 at the rear of the reel member 35, serving thereby to locate reel member 35 endwise on the shaft. As bolt is tightened, it forces the wedge-shaped members 43 together at both ends of the reel member 35, thus effectively sealing the reel member 35. The tight fits at these points on shaft 31 also provide the necessary driving engagement of member 35 with mounted concentrically upon a rotatably mountplained above, tapering reel l2 has relatively little eifect on the residual shrinkage capacity of the thread. In all other respects, the em-= bodiment of the invention shown in Figure 3 is similar to that shown in Figure 2.

As is apparent from Figures 4 to 6, inclusive, each of reels i2 and It comprises two wholly rigid reel members, each such reel member being of substantially circular cross section. Each reel member has a periphery made up of a plurality of longitudinally extending bar members which are interleaved with the bar members of the other reel-member. The two reel members rotate about axes displaced from and inclined to each other in such manner,v as to advance the thread in a large number of closely spaced, generally helical turns from 'the supported end to the unsupported end thereof.

Reel i2, as canhe seen from Figures 4 and 5, comprises two rigid reel members 35 and 36 each of which is substantially circular in cross sec- .tion. Member 35, which may be termed the concentric member, is mounted concentrically upon and for rotation with hollow drive shaft 31. Its periphery is made up of a plurality of spaced, longitudinally extending bar members 38. Member 36, which may be termed the eccentric member, is rotatably mounted with its axis inclined to but in a plane slightly offset from the axis of reel member 35. Its periphery includes a plurality of spaced, longitudinally extending bar members 39 alternately disposed with respect to bar members 38 of concentric reel member 35;

Concentric member 35 may be formed as shown with the bar members 38 integral with hollow body portion 58. In the illustrated reel, front and rear members 4| and 42, respectively, form fluid-tight junctions with hollow body portion 30. Said members also surround hollow shaft 31. Cooperating annular sealing members 43 disposed in recesses Min members 4| and 42, which sealing members are wedge-shaped in cross section, operate to prevent the escape of fiuid past the shaft from the interior of reel member 35.

bearings 6! and 62.

ed supporting member 5|, as by bolts 52. Rigid cagelike member 50. comprises the aforementioned bar members 39 which are fixed at their supported ends to an external annular supporting rib 53 by means of which the cagelike member is mounted on said supporting member 5|. An annular reinforcing member 58 is fixed to the bar members 39 at theirunsupiaorted'ends. Supporting member 5| is mounted on frame member 55 for rotation about an axis disposed in the desired offset and inclined relationship with respect to the axis of rotation of concen tric member 35.

Supporting member 5| is formed so that pro jecting boss 56 of frame member 55, on which said member 5| is rotatably mounted by means of spaced antifriction bearings 51, is disposed within the reel proper. To this end, the rear closure member 42 of the concentric member 35 is so positioned that the boss 56 can be disposed within the reel member 35. The purpose of this arrangement is to provide a construction such that, although the fiuid supply and removal means are associated with said frame member 55, the overall length of the reel and its supporting member is only slightly, if at all, greater than one of the liquid processing reels 6 to H, inclusive. Thus, a reel of this type can be substituted, if desired, for any one of the liquid processing reels.

Reel i2 is similar to the liquid processing reels in that its frame member 55 is provided with a flanged portion 58 adapted to be held by set screws 60 in a cup 59 fixed to frame 16 of the apparatus (Figure 2);

- Drive shaft 31, on which concentric member 35' is rigidly mounted, passes through frame member 55, being journalled therein by spaced In the reel illustrated in Figures 4 and 5, an annular, internally toothed member 63 fixed to the inner wall of hollow body portion 40 meshes with external teeth 64 formed on supporting member 5|, thus providing means for driving the eccentric member from the concentric member without contact of the bar members of the reel members. The bar members, being formed of a metal such as aluminum which is chosen for its high heat conductivity, would otherwise wear easily.

Bevel gear 65, fixed to the rear end -of shaft 31, meshes with bevel gear 66 mounted on vertically inclined drive shaft 61; similarly, each of the other reels 6 to M, inclusive, is driven from drive shaft 61.

Reel I2 is heated by the circulation of a suitable heating fluid through the hollow body'portion 40 of concentric reel member 35. As is stationary memberv 12 against which bears a Suitable Member 36a, which may be termed the eccentric member, is rotatably mounted with its axis slightly offset from and inclined to that of mem-- ber 35a. Its periphery includes a plurality of spaced, longitudinally extending bar members members 38a of reel member 35a.

rotatable bearing member 13 urged thereagainst by a spring 14, Spring 14 is compressed between a flexible annular sealing member 15 seated on member 13 and a support 16 rigidly fixed to the drive shaft 31, as by a set screw 11. The support 16 in compartment 68 serves both seals N therein, while the support I6 in compartment 69 serves a single seal. Said seals aid in locating. the drive shaft 37, and consequently the reel member 35,

endwise of the reel.

Compartment 6B is provided with an opening :18 through which heating fluid is supplied from tube 19 connected to' frame member 55. The

heating fluid passes through a port 80 in the wall ofhollow drive shaft 31, thence longitudinally of said drive shaft, and finally through port 82 into the interior ofhollow body portion 40.- The heating fluid passes out of said hollow body porshaft 31'which opening communicates with an interior tube 84 rigidly fixed in said drive shaft.

The plug 41 at the unsupported end of hollow drive shaft 31 serves to separate the inner tube and the drive shaft and to prevent fluid from passing directly from the.drive shaft to the .tube

,tion 40 through an opening 83 in hollow drive or vice versa. A similar plug 85 at the rear portion of said drive shaft 31 prevents the inter,- mixing of the entering and discharging fluid.

port 86 into the rear compartment 69, from which it passes out through opening 81 to a discharge In the apparatus shown in Figure 2, supply ,The fluid passes from said inner tube 84 through tube 19 is connected to a supplyconduit 89 which extends lengthwise of the apparatus in such -manner as to permit it to serve a plurality of reels I? disposed lengthwise oft-he machine as a whole. Similarly, discharge tube 88 communicates with a discharge conduit 90 which extends lengthwise of the apparatus to permit it to accommodate a plurality of reels l2. Regulating valves 92 may be provided, as shown, to control-the flow of heating fluid through the reel l2. The heating.

fluid may be hot water, steam or. any other suitable fluid which may be heated .and circulated through the system. Other heating and circulating means than that illustrated may of course be employed.

The reel member 35 and the bar members 38 thereof are thus directly heated by the fluid circulated therethrough. The other reel member 36, and particularly the bar members 39 thereof,

are heated by radiation and conduction from concentric reel member 35. This arrangement is particularly efficient for drying thread, which is the subject matter of Bergmann Patent 2,281,406. Reel I4 is similar in many ways to reel t2 and operates in a generally similar manner. .As appears from Figure 6, it comprises two wholly rigid reel members 35:; and 36a. Concentric member 35a, the periphery. of which is defined by a plurality of spaced, longitudinally extending bar Concentric member 35a is formed as shown with its bar members 38a integral with a hollow body portion 40a. Members Ma and 42a, forming fluid-tight junctions with said body portion 40a, not only close off the ends of said body portion but serve as means for mounting the reel member 351; on drive shaft 31a. Reel member 35a is held on drive shaft 310 against a collar 49a, fixed to-said drive shaft, by bolt 45a threaded into the end of said drive shaft. Packing 93, which is disposed in a recess 44a in member 42a, is compressed against collar 49a in order to prevent the escape of heating fluid from the interior of body portion 40a.

Eccentric reel member 36a is formed of a rigid cagelike member 500 concentrically mounted upon a rotatable supporting member 5la by means of bolts 52a. Rigid cagelike member a comprises the bar members 39a. fixed at their supported'ends to an external annular reinforcing rib 53a, by means of which said cagelike member 50a is mounted on rotatable supporting member 5Ia, 'and an annular reinforcing rib 54a fixed to the bar members 39a at their unsupported ends. Supporting member SM is mounted by means of spaced anti-frictionbearings 51a upon frame member 5512 for rotation about an axis disposed in the desired offset and inclined relation with respect to the axis of rotation of concentric member 35a. 5

An externally toothed member 6441 closure member 42a engages an annular internally toothed member 6311 on supporting member 5|a, thus driving eccentric reel member36a from concentricreel member 35a. 7

Drive shaft 31a is journalled in frame member- 55a by means of bearing Gla disposed at the unsupported end of said frame member and by means of antifriction bearing 62a supported in a cross member 94 fixed to the spaced, longitudinally extending members 95 forming part of frame member 55a. It is positioned against andwise movement between collar 49a and collar 96 hearing against the inner race of antifriction bearing 62a. Drive shaft 31a is rotated by means of a bevel'gear 65a mounted on said shaft between the longitudinally extending members 95. Bevel gear 65a meshes with a corresponding gear 'on inclined drive shaft 61. v Frame'member 55a is provided with a flanged portion 58a adapted to flt closely into and to be held in a cup member 5911' fixed to the frame of the apparatus, whereby reel II is demountably supported in the apparatus. I

The means for circulatin heating fluid through the reel is generally similar to that-above described. -A fitting '91 mounted on the longitudinally extendi'ng'members of frame member 5511 is provided with two compartments 68a and 69a. The drive shaft 31a projects into the forward compartment 68a, while tube 84a, fixed in said hollow drive shaft 31a, extends into rear compartment 691:. 'Suitable plugs 41a-and 95a are provided in said hollow drive shaft31a to support inner tube 84a .and prevent fluidfrom passing directly from hollow driveshaft 31a to members 38a, is mounted concentrically upon and for rotation with hollow drive shaft 31a.

on rear Heating fluid is supplied to compartment 68a through opening 18a and passes through ports 81a into the space between the inner tub 84a and the inner surface of hollow drive shaft 311:.

The fluid passes out of said hollow drive shaftthrough ports 82a into the interior of body por-,

tion 40a of concentric reel member 35a. After circulating through said body portion, the fluid passes through ports 83a into the interior of inner tube 84a, whence it is discharged into the rear compartment 69a. The heating fluid passes out of said compartment through port 81a.

In the embodiment of the invention shown in Figure 2, heating fluid is supplied through conduit 89a which extends longitudinally of the machine. Tube 19a conducts the heating fluid from conduit 89a to entrance port 18a of reels l4. After the heating fluid has circulated through the reel, it passes through a tube 88a connected to the discharge port 81a to a discharge conduit 90a extending longitudinally of the apparatus. The heating fluid for reels l4 may comprise any suitable medium such as hot water, steam or other suitable fluid.

Using the methods and apparatus of the invention, it is possible to produce by a continuous process viscose artificial silk thread having a highly uniform residual shrinkage capacity in the neighborhood of one per cent. The precise value in a given case depends upon various factors, but' will usually be found to be within the range between three quarters and one and one quarter per cent. All other physical and physlcochemical characteristics are likewise extremely uniform. The example which follows is illustrative of the practice of the invention, the apparatus employed being that illustrated in Figures 1 and 2.

Viscose artificial silk thread of 150 denier, 40 filaments, is delivered at a speed of 68 meters per minute to reel 12, which is preferably made of aluminum. Still in the gel state when it ,is passed to the reel, the thread has a moisture content of approximately 400%. The thread is at ordinary room temperatures before it is taken up by the reel, which is heated to at least 115 C.; so that it is subjected on the reel to a sudden rise in temperature of approximately 90 C.

At the high temperature to which the reel is heated, the moisture is' rapidly driven from the thread. The thread advances several turns before it begins to shrink; accordingly, the reel is of substantially cylindrical configuration for about 1.5" lengthwise of its thread-bearing periphery, measuring from the supported end of the reel. From this portion, where the reel is of 5" diameter, the reel is tapered to a diameter of approximately 4.9", this in order to allow forshrinkage of the thread during the phase of the drying operation during which the internal moisture is removed from the thread.

The last few turns of thread at the unsupported end of the reel; i. e., for a distance of about A lengthwise of the periphery of the reel, are rewet with an aqueous rewetting liquid after the thread has been dried but while it is still at an elevated temperature. The rewetting is preferably done by applying the liquid to the thread at the rate of about 30 cc. per minute, the rate being determined by the amount of moisture fabric.

which can be reabsorbed by the thread. The thread will ordinarily absorb the rewetting liquid only until it attains a moisture content slightly in excess of 200%.

The application of the rewetting liquid results in elongation of the thread, wherefore reel I3 is 5' in diameter at the portion on which the thread starts. It revolves at the same angular velocity as the preceding reel, the difference between the 5" diameter of reel l3 and the 4.9" diameter of reel 12 being suflicient to allow the thread to pass from reel i2 to reel I 3 without slackness or tension. Reel [3, being formed of hard rubber or other plastic material, is not heated, but is of the same type as reels 6 to II, inclusive. The reel is of substantially cylindrical configuration throughout its length, having a thread-bearing periphery in the neighborhood of 5" long.

As it leaves reel I3, the thread has a highly uniform moisture content of approximately 200%, based on the weight of the thread.

Reel [4, on which the flnal drying of the thread is accomplished, is ordinarily designed to be heated to a temperature not greater than 0., depending upon the nature of the thread being dried. In the instant example, it is heated to about 78 C. An initial length of 1.5" of the periphery of the reel nearest the supported end is substantially cylindrical. The next 3.5" of the length of the reel is tapered to allow for shrinkage of the thread in the absence of substantial tension. The last 1.5" is substantially cylindrical to allow for complete drying of the thread after completion of the shrinkage. reel I4 is of aluminum.

Under these conditions, no loops form in the thread during the second drying operation, this even though the thread permitted to shrink freely. The thread is characterized by straight filaments of highly uniformcharacteristics. By contrast, thread which is dried only once, even with substantially unrestrained shrinkage, is

characterized byloops in its filaments which not only impair the appearance of the thread but also introduce difiicuities in forming the thread into This fact, together with the fact that on rewetting the thread absorbs at most considerably less than its original moisture content; e. g., in the neighborhood of one-half of its original moisture content, indicates that a change in the structure of the thread takes place in the course of the first drying operation.

Both the methods and forms of apparatus above described as embodying the invention are susceptible of various modifications without departing from the spirit of the present invention. For example, more drying operations, with intermediate rewetting, may be employed than those specifically disclosed and other means for and methods of rewetting than those illustrated may be used. Either-as disclosed or as modified, the illustrated methods and forms of apparatus may be employed for other uses; for example, the drying of materials other than textile thread per se. The term thread" in the appended claims is intended to include similar materials capable of being operated on and handled according to the present invention.

It is intended that the patent shall cover, by suitable expression in the appended claims, what ever features of patentable novelty reside in the invention.

What is claimed is:

1. The method of continuously drying wet mul- Like reel l2,

tiple filament viscose artificial silk thread comprising the successively performed steps of applying heat to the thread while continuously but temporarily storing it in extended form in a series of generally helical turns, the amount of heat applied to the thread being suffici'ent to dry it substantially completely; continuously rewett-ing the thread with an aqueous liquid heated to a temperature near the boiling point of water, the thread being in extended form at the time the 11) 'essing medium of any kind,,the period of storage being long enough to permit excess liquid carried by the thread to drip therefrom; and, while continuously but temporarily storing the thread in extended form in a series of generally-helical turns at least some of which are of progressively decreasing diameter-{again applying heat to the thread inan amount sufilcient to dry it substantially completely. j

2. A- method as in claim 1 in which the rewetting liquid is-applied to the dried thread before it has had an opportunity to cool appreciably.

3. A method as in claim 1 in whichthe first drying operation is carried out at a temperature above the boiling point of the rewetting liquid. 4. A method'as in claim 1 in which the'second drying operation is carried outat a. temperature below the boiling point of the rewetting liquid.

' LOUIS S. FRYER.

EMERSON B. HELM. KENNETH M. McLELLAN..

QCERTI F ICATE OF comcwiom "'Novenber 2J4, 1%2, Louis s. FRYER, "ET AL. It '1s hereby ear-titled e rz pr eppear s-in the. pz ipted aficific'atiofi of the abovenmnb ered 'pzitent if equiring cdr recfiion asfollows; Page 2,1 sec- LeiEt QPafien t shpugld' be read with thf ls coi'recti'on' therein th at -the same may confionrto the record 91 the. ease in the Patent Office;

Signed and sealed this 29th da of December, D. 19%2.

v Henry Van-Ar'sdale (Seal) Acfiing- -c o mmiesioner ef- Patents.

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