US2030972A - Apparatus for the production of artificial filaments and like materials - Google Patents

Description

H. DREYFUS 2,030,972

APPARATUS FOR THE PRODUCTION OF'ARTIFICIAL FILAMENTS AND LIKE MATERIALS Feb. 18,1936.

Filed May 2, 1953 \wwudw I Hymns 3 H? Patented Feb. 18, 1936 UNHTED STATES FATENT FFHQE TERIALS Henry Dreyfus, London, England Application May 2, 1933, Serial No. 668,926 In Great Britain May 19, 1932 4 Claims.

This invention relates to apparatus for the manufacture of artificial materials, and is particularly concerned with improvements in the spinning jets or nozzles used in the production 5 of artificial filaments or like extruded products.

The invention is of particular importance in connection with the spinning of filaments at high speeds and the spinning of fine filaments, whether at high speeds or otherwise.

Spinning jets for the production of artificial filaments are usually and most conveniently made of sheet metal, pressed or otherwise formed into the shape of a shallow cup, the fiat bottom of which is pierced with orifices for the extrusion of the filaments. A spinning solution is supp-lied inside the jets under pressure, and is thereby forced through the orifices to form the filaments, the faster the required rate of extrusion and the finer the orifices the higher being the pressure which must be applied to the spinning solution behind the face of the spinning jet. In spinning at high speeds therefore, and especially in the spinning of fine filaments the pressure behind the jet may be so high as to cause the jet to bulge outwardly. The phenomenon of jet bulging gives rise to many difiiculties. Thus for example, in a bulged jet, the spinning orifices point outwards and cause the extruded filaments to spread instead of proceeding as a parallel compact bundle. It is an object of the present invention to reduce or overcome the difiiculties outlined above, by reducing or preventing the bulging of the jets.

According to the present invention, a sheet metal jet for the purpose of spinning is thickened locally over areas not occupied by the spinning orifices, with the result that the sheet metal is reinforced and the tendency to bulging is reduced or avoided. At the same time the metal through which the orifices are bored is not increased in thickness, with the result that the length of the passages is not increased, a factor of some importance, not only bearing upon the pressure necessary to force the spinning solution through the orifices, but also having its eifect on the nature of the thread produced.

It is preferable that the metal of which the jet consists should be thickened in lines which run generally in radial directions, thus affording the greatest reinforcement against bulging. If desired, however, one or more circles of thickened metal concentric with the jet face may be employed in conjunction with the radial lines so formed, such circles helping to reinforce the jet between the radial lines. Thus, for example, it is a convenient practice to arrange the spinning orifices in a circle on the face of the jet, and such a jet may be strengthened by a circle of thickened metal inside and/or outside the circle of filaments and by radial ribs, which ribs may, if desired, terminate in a circle or boss within the circle of orifices.

The thickening of the sheet metal in the manner described above may be effected by any convenient method. Thus, for example, the sheet metal of which the jet is to be formed may be stamped or pressed, so that the desired pattern of thickened portions is produced, and such stamping may be effected at any convenient stage, but preferably before the boring of the orifices, which may be subsequently formed in the thin part of the metal.

The invention is of especial advantage in its application to jets having a large number of orifices, such as are usually employed in the spinning of fine filaments. The great number of orifices requires a greater area of jet face, and this results in an increased tendency of the jet to distort, especially where the orifices themselves are of small size and so necessitate a greater extrusion pressure. Further, the greater distance of the orifices from the centre of the jet resulting from the larger area of the jet face occupied by the orifices, increases the spreading of the filaments as they issue from the orifices. Again, jets of large face area may be used in order to accommodate a large filter member immediately above the jet, as is of especial importance in high speed spinning. These jets are apt to distort to a greater extent than jets of small face area, irrespective of the number, size or position of the orifices. While both the size of the jet face and that of the circles of orifices may be reduced as far as possible in such cases, the present invention is nevertheless of particular advantage when the extent to which such reduc- 40 tion can be carried out is limited.

While the spinning jet according to the present invention is applicable generally to the production of artificial filaments by extrusion, whether by the wet or coagulation method as usually employed in the spinning of viscose or cuprammonium filaments, or by the dry or evaporative method, as usually employed in the spinning of filaments of cellulose acetate or other organic derivatives of cellulose, the invention is especially useful in the production of filaments by the dry or evaporative method because of the high spinning speed and high concentration of spinning solution, generally adopted in this method .of 55 spinning and the resultant higher pressures on the jets.

Some specific forms of jet according to the invention will now be described by way of example with 'reference to the accompanying drawing, in which:

Figure 1 is an elevation in half section of a nozzle assembly embodying one form of spinning jet;

Figures 2 and 3 are a plan and sectional elevation respectively of the spinning jet shown in Figure 1; and

Figures 4 and 5 are views similar to Figures 2 and 3 of a further form of jet according to the invention.

Referring to Figure 1, a pipe I for the supply of spinning solution is provided at its lower end with a connecting piece 8 which is cut with screw threads 9 on its periphery and has a machined face II]. A large nut I I is screwed on to the piece 8 in order to secure against the face II] a filter I2 and a spinning jet I3. It will be noted that the connecting piece 8 expands to a relatively large diameter and that the filter I2 and jet I3 are consequently of large area.

As shown in greater detail in Figures 2 and 3, the jet I3 comprises a securing flange I4 and a face I5 in which are bored two concentric circles of orifices I6, I'I. Inside the inner circle of orifices H, the thickness of the jet is increased to form a boss I8 from which four ribs of thickened metal I9 run radially outwards to the edge of the face I5. Outside the inner circle of orifices I1 and inside the outside circle I6 is a circle of thickened metal 20 concentric with the face I5 and running into the ribs I9. The ribs l9 divide the orifices I6, I! of each circle of orifices into four quadrants, no orifices being bored through the thickened metal of the ribs I9. The provision of the ribs I9 provides a strong resistance against the bulging of the jet due to the pressure of spinning solution being forced through the orifices IS, IT. Further reinforcement is provided by the boss I8 and circle 20. By reinforcing the jet in this manner, the area of the jet, and in consequence the number of orifices which may be bored therein is considerably increased. The thickening of the jet is formed on the inside of the jet, so that the outside face remains smooth soas to be easily cleaned when necessary.

It will be understood that, in the drawing, the thickness of the metal of which the jet is formed is exaggerated for the purpose of clarity. A suitable thickness for the unthickened portions of the jet is about .01, while the thickened portions may be increased to any desired extent, e. g. from .02 to .1" or more. Likewise, the size of the orifices is much exaggerated.

In Figures 4 and 5, a spinning jet is shown having a single circle of orifices 23. The face I5 of the jet is reinforced with six radial ribs 26 dividing the circle 23 into six parts. The ribs 26 originate from a circle 21 of thickened metal inside the circle of orifices 23, and a further circle 28 of thickened metal is provided outside the circle of orifices. As in the jet shown in Figures 2 and 3, the ribs 26 and the circles 21 and 28 reinforce the face I5 of the jet against bulging.

What I claim and desire to secure by Letters Patent is:-

1. A spinning jet for the production of artificial filaments, yarns, threads or the like, said jet having a face of thin metal provided'on the inside of said face and integral therewith, over areas not occupied by spinning orifices with lines of increased thickness adapted to reinforce said face, the outer face of said jet being left smooth to facilitate jet Wiping.

2. A spinning jet for the production of artificial filaments, yarns, threads, or the like, said jet having a face of thin metal provided on the inside of said face and integral therewith, over areas not occupied by spinning orifices, with radial lines of increased thickness adapted to reinforce said face, the outer face of said jet being left smooth to facilitate jet wiping.

3. A spinning jet for the production of artificial filaments, yarns, threads or the like, said jet having a face of thin'metal provided on the inside of said face and integral therewith, over areas not occupied by spinning orifices, with circles of increased thickness concentric with said face and adapted to reinforce said face, the outer face of said jet being left smooth to facilitate jet wiping.

4. A spinning jet for the production of artificial filaments, yarns, threads or the like, said jet having a face of thin metal provided on the inside of said face and integral therewith, over areas not occupied by spinning orifices with radial lines and circles of increased thickness adapted to reinforce said face, the outer face of said jet being left smooth to facilitate jet wiping.

HENRY DREYFUS.

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