US2586970A

US2586970A - Apparatus for spinning artificial filaments

Info

Publication number: US2586970A
Application number: US66027A
Authority: US
Inventors: Henry J Mcdermott
Original assignee: American Viscose Corp
Current assignee: Akzo Nobel UK PLC
Priority date: 1948-12-18
Filing date: 1948-12-18
Publication date: 1952-02-26
Anticipated expiration: 1969-02-26
Also published as: FR1001166A; BE492707A; GB675681A

Description

Feb. 26, 1952 J, MCDERMOTT APPARATUS FOR SPINNING ARTIFICIAL FILAMENTS Filed Dec. 18, 1948 INVENTOR. HEN/1?) J. McDERMOTT flaw/19% I Patented Feb. 26, 1952 APPARATUS FOR SPINNINGARTIFICIAL FILAMENTS Henry J. McDermott, Collingdale,

Pa., assignor to American Viscose Corporation, Wilmington, Del., a corporation of Delaware Application December 18, 1948, Serial No. 66,027

8 Claims.

1 This invention relates to apparatus for the manufacture of artificial filamentary material. In the manufacture of artificial filamentary material from viscose, for example, in accordance with the wet spinning method, viscose of a suitable viscosity is delivered from a tank or the like by a metering pump to a spinneret from which it emerges into an aqueous spinning bath in which the viscose is coagulated with accompanying at least partial regeneration of the cellulose. The spinneret is positioned below the level of the spinning bath and is connected with the viscose-containing header through a pump and candle filter located alongside, above, or below the bath by means of a pipe or rounder, conventionally, a piece of piping which provides as direct and undeviating a path for the viscose traveling to the jet as is possible.

The spinning apparatus is more or less standard but usually there exists a temperature di'fierential as between the spinning bath and the entering filaments of as much as C. or more.

It is an object of the present invention to pr vide an improved wet spinning system using a spinning bath between 40 and 100 0., in which the temperature difierential between the coagulating bath and the viscose as it issues into the bath is reduced by heat transfer between the bath and the viscose through a tortuous rounder. A further object is to provide a rounder having a tortuous channel which rounder is readily removable from the bath to interrupt heat transfer from the bath to the viscose when spinning is to be interrupted and the pumps are to be stopped for any reason. A further object is to provide a wet spinning system in which each spinneret is assuredly repositioned at the same depth in the bath every time it is returned to spinning position in the bath, thereby assuring that the same temperature differential between the bath and the viscose entering it is obtained so that the thread collected is as nearly uniform as possible in the individual wound package and in the several packages collected in succession, even though spinning may be interr'uptedat times and the spinneret be withdrawn from and returned to the bath, such as during the dofiing periods. Other objects and advantages of the invention will appear from the drawing and the description thereof hereinafter.

In the drawing, illustrative of the invention,

Figure 1 is an elevation of one embodiment of the invention, the bath container being in section,

Figure 2 is a similar view of amodification,

Figure 3 is a similar view of another modification, and

Figure 4 is a section on line IV-IV of Figure 3.

Briefly stated, the invention resides primarily in the provision of a novel pipe or rounder of special construction for connecting the spinneret with the tank or other supply from which the spinning solution is delivered. Generally speaking, the novel rounder, which is preferably circular in cross-section and formed from a heat-conductive material, consists of a length of piping which comprises a portion leading into the bath, a portion leading to the spinneret, and between the two and adjacent the spinneret a portion which provides a tortuous channel through which the spinning solution travels just prior to extrusion, theconstruction being such that the portion of the rounder providing the tortuous channel is submerged below the level of the spinning'bath when the rounder is in use. More specifically in the case of horizontal spinning, the fitting comprises a'length of piping, preferably circular in cross-section, which is bent through a angle to provide a generally vertical portion leading into the bath and a horizontal portion leading to the spinneret which is supported on the free end thereof, the horizontal portion comprising a tortuous convoluted or coiled channel in the form of a helix comprising a series of ovalshaped or circular convolutions, a spiral, or the like, adjacent its spinneret-supporting end. For vertical spinning, the construction is substantially the same except that the end of the horizontal portion is bent upwardly to provide another vertical portion extending therefrom, the spinneret being supported on the end of the second vertical portion. In either case, the tortuous channel is positioned below the level of the bath, when the pipe is in use, which serves to increase the area available for the transfer of heat from the bath to the spinning solution just prior to extrusion of the latter through the spinneret, advantage being taken of the increased time of exposure of the viscose traveling along the tortuous channel in the pipe to the heat of the spinning bath itself to control the temperature of the viscose, such exchange of heat'being efiected as closely as feasible to the spinneret so that the viscose thus heated does not have an opportunity'to cool prior to entering the spinneret. By thus increasing the area available for the conduction of heat'from the bath to the spinning solution, the bath and the entering filaments have about the same temperature, avoiding any substantial temperature differential as between the heated bath and the viscose, and insuring delivery of the solution to the bath in a smooth continuous stream or streams, and the obtention of even threads of uniform denier throughout.

The accompanying drawing is illustrative of the invention. In the drawing there is shown a tank 2, which may take the form of a trough extending the length of the machine, containing a spinning bath 3, in which is supported a spinneret 4, or a plurality of such spinnerets spaced along the trough. The spinneret is mounted on one end of a rounder pipe 5 which comprises a vertical portion 6 and a horizontal portion l. Portion 1 comprises a tortuous channel constituted by a plurality of helical turns 8 (four shown) which are submerged the spinning bath. The free end of portion 9 is threadedly or otherwise connected to a vessel, such as a candle filter 0 which is in turn connected to thedischarge outlet of a pump 10 by pipe H, which is in turn connected by a pipe IE to a"headr 13 which is connected to an outlet in a tank (not shown) containing the fiber-forming solution. The assembly of candle filter 9, rounder, and spinneret is mounted forswiv'elling about an axis I4 coincident with the axis oi the entry pipe for the filter 9 so that the rounder assembly can be swung upwardly out of bath 3 into a position in which the spinneret 4 drips into awaste container or trough 15 supported on one or more brackets it. The upper ed'ge H of the wastecontainer or the upper edge 18 of the trough 2, or both such edges, may serve to limit the extent of submerging of thereunder assembly. If desired, calibrations l9 maybe provided on the upstanding portion 5 of the rounder so that the depth of the assembly can beascertained and predetermined independently of the limiting edges i1 and L8. M

Viscose or other suitable spinning "solution is pumped through pipe 5, through thespinneret, from the orifices of which it issues as a plurality of streams which, under the action of the s'e'tting bath, are set up in the form of individual continuous filaments or threads. In the case of viscose, the setting bath is normally maintained at a temperature of about 40 to 50 C., although the temperature may vary up to 100 C. for special purposes. Experience has shown that, under normal conditions and using conventional devices, the temperature of the viscose entering the bath is usually from 10 to 20 C. lower than that of the bath, the higher the bath temperature, the greater the difierential. In the present case, on the other hand, using a pipe or rounder of the construction disclosed herein, the viscose entering the bath preferably has about the same temperature 'as the heatedba'th, or at least the temperature of the entering filaments more nearly approximates the temperature of the bath, the viscose being brought to'a temperature of at least 40 C. in normal spinning at bath temperatures up to 50 C. and the viscose being brought to at least 50 C. when higher bath temperatures up to 100 C., preferably 60 ,to 70 C., are used. This heating of the viscose results from exposure to the heating eflect of the bath during its travel along the tortuous channel in the pipe, which channel aifords ample time for the transfer of heat from the bath through the walls of the pipe 7 c v The length of rounder needed to be'submerged in he a h depends on the material oi which it 4 is made and the diameter of bore, as well as the extrusion rate. For the conventional 4" diameter glass rounder, a submerged length of at least two feet is needed to provide the minimum heat transfer requirement when the viscose has an initial temperature before heating of 28 C. or less, the bath temperature is 40C., and the extrusion rate is over 40 grams per minute through the holes of a single spinneret. Adjustments can be made for rounders of different diameters diiierent materials, and for different extrusion rates as well as for various difierentials between the initial viscose temperature and the spinning bath temperatures. When the spinning bath temperature is above 50 C., the rounder is designed to raise the temperature of the viscose to at least 50 C., whereas for spinning bath temperatures up to 50 C., the preferred procedure is to raise the viscose to substantially the same temperature, but in amy event,'when the bath tempera'tureis 50 or lower, the temperature of the viscose should be at least 40 C.

In Figure 2, the rounder 20 extends from the candle filter or vessel 2| mounted in 22 and comprises a plurality of helical convolutions 2 3' which may take the form either of a circular :or oval loop. These convolutions in this embodiment are considerably larger in diameter than the spinneret coupling and may be anywhere from 2 to 6 inches in diameter, preferably 3 or} inches. The convolutions extend back from the downwardly extending portion of the rounder 20 which is bent at 24 into a generally horizontal forwardly extending portion 25 which extends through the center of the loops and supports the spinneret 26 and its coupling 21 at the end. shown in Figure 1, the rounder is removably supported in a spinning bath container or trough 2 and a waste trough 15 may be provided to receive drippings when the assembly is swung out of the bath.

Figures 3 and 4 show a modification in which an individual container 30 is provided for each rounder assembly 3l. The rounder extends from the discharge connection 32 of a candle filter 33 carried on a bracket 34 pivotally mounted at 35. The viscose to be fed through the candle filter is led thereto by a pipe 36 which passes through a sealed rotary joint at the swivel connection 35. A tray 31 is provided to receive drippings from the spinneret 38 when the rounder assembly is swung out of the coagulating bath. In the container 30 for the coagulating bathya vertical partition 39 is provided and has an'opening 40 beneath the spinneret. A feed pipe 4| may be provided to supply the coagulating bath into the narrow space between this Vertical partition 39 and the adjacent wall so that the bath must flow through opening 40 into the container 30 beneath the spinneret therein. Another vertical partition 42 is provided and extends at right angles to the partition 39. This partition extends downwardly in the bath but its lower edge 42a is spaced a short distance from thefloor of the bath. The partition 42 is placed a short distance from the adjacent wall of the containerto provide a narrowehannel 43 through which the spent coagulating bath passes upwardly from under the edge 42:: and over the bottom of the weir 44. Back of the weir, 44,, there is provided a trough or basin 45 which is connected by apipe 46 to a header 41. The header may run the length of the machine which may comprise a plurality of these individual filament-coagulating set-ups.

The rounder has a downwardly extending portion 31a, a tortuous portion 3lb, comprising a number of helical convolutions (about 3 to 4 being shown) and a short upwardly extending portion 3Ic.to which the spinneret 38 is connected by the coupling 48. A projection 49 may be provided to act as a stop member to position the spinneret at the same level in the bath upon every submersion therein. For this purpose, the partition 39 is provided with a recessed portion, such as the shoulder or ledge 5i).

In all embodiments of the invention, the rounder assembly is adapted to be swung out of the bath so that whenever it is necessary to stop the spinning pumps for any reason, such as to allow operators to clean or repair the machine, or during weekend or holiday interruptions of the machine, it is only necessary to swing the rounder out of the bath and to flush the rounder with viscous at the temperature at which it is supplied before the pump or pumps are stopped. The derivation of heat for the viscose from the coagulating bath through the rounder which is swingable out of the bath, assures the proper heating of the viscose during the spinning operation, and at the same time prevents heating and consequent rapid hardening of the viscose in the rounder when spinning is not proceeding. Furthermore, by the practice of this invention, in accordance with which the heated spinning bath controls the temperature of the spinning solution being extruded, the viscose is maintained in the desired state of fluidity, the flow thereof through the spinneret is eased and higher extrusion rates and spinning speeds can be attained.

The present invention provides for the heating of viscose by a means which does not require addi tional parts, which is simple in construction, manufactured at insignificant increase in cost, which is extremely efiicient for the purposes intended, and which does not require any change in spinning conditions or arrangement of parts. When a pipe or rounder of the type disclosed herein is used to permit exposure of the spinning solution to the heating effect of the spinning bath itself, over a relatively prolonged period and just prior to extrusion of the solution, the spinning solution passing through the rounder associated with all of the many units of a conventional spinning machine is heated to approximately the temperature of the portion of the spinning bath surrounding each rounder. It is of the utmost importance that the present invention also avoids trouble arising from hardening of the viscose on the rounder when heating attachments are connected to the rounder and flow of viscose is interrupted for any reason. In the present invention, the prolonged heating of the viscose is avoided until it is about to be extruded and this heating is automatically stopped when the rounder is swung out -of the spinning bath and spinning is interrupted.

The novel pipe or rounder may be used in both vertical and horizontal spinning, it being only necessary that the portion comprising the tortuous channel between the portions leading, respectively, into the bath and to the spinneret be located as close to the spinneret as feasible, and adapted for positioning below the level of the spinning bath in use.

Various modifications may be made in the invention specifically described and illustrated,

without departing from the spirit and scope of 6 the invention which is not -to be limited, therefore, except as necessitated by the appended claims. V I

I claim:

1. Apparatus for spinning artificial filaments comprising a container having a closed bottom wall for supporting a heated liquid spinning bath, a spinneret normally positioned in the container during spinning, a spinneret coupling, a projecting lug secured to the spinneret coupling, a pipe, connected at one of its ends to the spinneret, formed from heat-conductive material and comprising a portionadjacent the spinneret-supporting end thereof bent into helical form and normally positioned in the container during spinning, means for mounting the pipe pivotally about an axis outside the spinning bath container whereby the spinneret and the helical portion of the pipe can be swung into and out of the spinning bath container, a vertical partition adjacent one wall of the container to provide a passage for the introduction of the spinning bath liquid and an opening at the lower end of the partition providing an intercommunicating passage between opposite sides of said partition so as to introduce fresh coagulating bath liquid into the container below the spinneret, said partition having a recessed portion adapted to cooperate with the projecting lug for positioning the spinneret.

2. Apparatus in accordance with claim 1 comprising another partition in the spinning bath container set at approximately right angles to the first partition and having its lower edge spaced from the fioor in the container to provide an extra passage to the coagulating bath.

3. Apparatus in accordance with claim 2 in I ing between the lower edge of the other partition and the fioor of the container.

4. Apparatus in accordance with claim 3 comprising a receptacle outside that wall of the container adjacent the second partition and a weir in the wall to allow overflow of the bath from the space between the second partition and the wall into the receptacle.

5. Apparatus for spinning artificial filaments comprising a container for a heated liquid spinning bath, a spinneret normally positioned in the container during spinning, means for conveying a fiber-forming solution to the spinneret comprising a pipe connected at one of its ends to the spinneret and having a tortuous portion formed into a plurality of convolutions or coils normally positioned in the container during spinning, means for mounting the conveying means pivotally about an axis outside the spinning bath container whereby the pipe and spinneret can be swung into and out of the spinning bath, means for introducing a spinning bath liquid into the container comprising a vertical partition adjacent one wall of the container to provide a chamber for the introduction of the spinning bath liquid and an opening at the lower end of the partition providing an intercommunicating passage between opposite sides of the partition to permit flow of fresh coagulating liquid from the chamber into the container below the spinneret, means for predetermining the position of the spinneret in the bath comprising a projecting lug secured to the spinneret and a recess in the vertical partition having a fixed surface adapted to be engaged by the lug.

6. Apparatus in accordance with claim 5 com- 7 prising another partition in the spinning bath container set at approximately right angles to the first partition and having its lower edge spaced from the floor in the container to provide an extra passage to the coagulating bath.

7. Apparatus in accordance with claim 6 in which the opening in the first partition is spaced at a higher level in the container than the opening between the lower edge of the other partitio and the floor of the container.

8. Apparatus in accordance with claim 7 comprising a receptacle outside that wall of the container adjacent the second partition and a weir in the wall to allow overflow of the bath from the space between the second partition and the wall 1 into the receptacle.

HENRY J. MGDERMQTT.

estate 8 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 823,009 Waddell June 12, 1906 1,835,956 v Lewis Dec. 8, 1931 2,243,116 Ostermann May 27, 1941 10 2,307,863 Soukup Jan. 12, 1943 FOREIGN PATENTS Number Country Date 364,081 Great Britain "a"; June 27, 1930