US1767216A - Apparatus for spinning solutions of cellulose ethers or esters - Google Patents

Description

MELITTA xLEi v, or VIENNA,

Patented June 24, 1930 PATENT OFFICE v AUSTRIA, ASSIGNOR T0 RUTH-ALDO COMPANY, INC.,

OF NEW YORK, N. Y.

APPARATUS FOR SPINNING SOLUTIONS OF CELLULOSE ETHERS OR ESTERS Application filed March 27, 1928, Serial No. 265,158, and in France June 22, 1927.

It is known that the spinning of cellulose ethers and esters is carried on in closed chambers or cells, in order to facilitate the collection and recovery of the volatile solvents employed.

It is also known that, with a view to ffiCllltating the evaporation of said solvents, sa d chambers or cells are usually heated by sultable means.

These arrangements are not a source of inconvenience when the spinning proceeds from below upwards, but, on the contrary, when the spinning proceeds from above downwards, the spinning nozzle is disposed right in the top part of the chamber or cell and thus in the hottest zone, the temperature of which upper zone is very high. Under these conditions, the cellulose issuing from the spinning nozzles is suddenly raised to this very high surrounding temperature, the effect of which is either to increase the fluidity of the spinning material and lower its viscosity, or to set up rapid evaporation of the solvent.

In all cases the resulting threads are defective and of inferior quality.

1 the chamber, in such a way that the cold air,

drawn towards the centre of the chamber, flows in a downward direction whereby the threads, as they issue from the spinning nozzle, are SubJected to a cold circumambient medium.

However, in order that this arrangement may be completely eflicacious, it is necessary to prevent airy considerable amount of hot air ascending from the bottom of the cell into the top. With this object, according to the invention, a diaphragm is disposed, at a suitable height, so as to divide the interior of the cell into two compartments and is mounted in such a way as to allow of the passage of the threads.

If, with a device of this kind, the aspiration drawing the air'laden with vapours of solvents from the cell into the recovery apparatus is properly regulated, the hot" air will not reascend from the zone below the diaphragm into the upper zone, but on the contrary, the cold air of the upper zone will be drawn through the hole provided, in the diaphragm, for the passage of the thread; and this cold air will pass into the lower zone, thereby facilitating the passage of the thread. In'this manner the spinning nozzle and the first portion of the path traversed by the thread can be maintained at the same temperature as theoutside air.

By way of example, a description will now be given of a spinning chamber provided with the improvements the principle of which has just been enunciated.

In the accompanying drawing, Fig. 1 is a vertical section through said chamber, Fig. 2 a plan of same, Fig. 3 a partial vertical section showing the diaphragm in the open position, and Fig. 4: a plan of the diaphragm.

Holes EE E are pierced in the top AB of the cell ABCD, for the admission of cold air. These holes, in convenient number, may be disposed circularly round the spinning nozzle F, situated in the centre of the top AB of the cell. The thread, represented diagrammatically by H, travels from above downwards and winds on the bobbin I located in the lower part of the cell. The aspiration is preferably eflected on a level with said bobbin I.

The diaphragm is indicated at MN. In the example under consideration, the diaphragm' is horizontal, and is composed of two portions, namely a fixed member MP, and another member PN adapted to pivot on a hinge P and resting, byv means of its edge N, on a projection 0 carried by the wall AC of the cell.

As can be seen in Fig. 4, the pivotal member PN of the diaphragm is provided with a notch TRS of such a shape that, when the apparatus is started, in commencing to spin, the movable member PN can be lowered and still leave room for the passage of the thread. In order to start the apparatus, this movable member is raised into the po-- sition shown in Fig. 3.

After theapparatus is started, the triangular notch TBS is closed, by an easily constructed and simple device, consisting of a sliding or rotating member, in such a way that onlythe small aperture necessary for the passage of the thread is left open in the diaphragm.

The heating may be efiected in any part whatsoever of the zone beneath the diaphragm. I

The device affords the advantage of keeping the first portion of the thread in continuous contact with cold air, this latter. merely absorbing the vapours (of the solvents) liberated in this first portion of the path of the thread. On the other hand, in the absence of a diaphragm, this portion of the thread travels in hot air, and, in the case of solvents whose vapours are lighter than air, is surrounded by an atmosphere highly charged with vapours.

Certain operations, such as drawing or stretching, can be carried out, under particularly favourable conditions, in a vapourladen medium. The presence of the diaphragm enables the intermediate and final portions of the ath of the thread to be precisely subjecte to these favourable conditions;

Finally, it will be understood that it is possible (and even advantageous in certain cases) to provide not only a single diaphra m but a plurality of diaphragms, dis pose thread. These enable the temperature, or the density of the vapours with whichfthe air is laden, to be regulated, according to requirements, at various levels in the cell.

I claim:

1. Apparatus for use in spinning artificial thread, comprising a spinning cell, means dividing the interior of the cell into superimposed zones adapted to be traversed successively by the spun thread, a spinning nozzle in the upper zone, means for admitting air to the uppermost zone about the spinning nozzle, and means'whereby hot air and solvent vapours can be drawn from the lowermost zone.

2. Apparatus for use in spinning artificial thread, comprising a spinning cell, at least one diaphragm dividing the interior of the cell into superimposed zones adapted to be traversed by the spun thread, a downwardly directed splnning nozzle in the upper zone,

means for admitting air to the upper zone about the spinning nozzle, and means,

whereby hot air and solvent vapours can be drawn from the lower zone.

3. Apparatus for use in spinning artificial thread, comprising a spinning cell, at least one diaphragm dividing the interior of the cell into superimposed zones adapted to traversed by the spun thread, a downwardly directed spinnin nozzle in the u per zone said diaphragm ein constituted y a fixed member and a notcied, movable member, means for admitting air to the up er zone about the spinning nozzle, an means whereby hot air and solvent vapours can be drawn from the lower zone.

' 4. Apparatus for use in spinnin artificial threads, comprising a spinning ce a downwardly directed spinning nozzle in the upper part of the cell, means for admitting cold air about the spinning nozzle and the thread issuing therefrom, and at least one diaphragm in the cell extending partly over the area thereof.

5. Apparatus for use in spinning artificial thread, comprising a spinning cell, a downwardly directed spinning nozzle in the upper part of the cell, means for admitting cold air about the-spinning nozzle and the thread issuing therefrom, at least one diaphragm in the .cell extending artly over the area thereof, and means w ereby hot air and solvent vapours can be drawn from the lower part of the cell below the diaphragm.

In testimony whereof I aflix my signature.

MELITTA KLEIN.

at various points in the path ofthe

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