US2871511A - Melt spinning apparatus - Google Patents

Description

Feb. 3, 1959 R. H. sPEAKMAN MELT SPINNING APPARATUS Filed Aug. 24. 1954 pam v M440 T TOR/V676.

Rcymo BY @MM United States Patent MELT SPINNING APPARATUS Raymond Holden Speakman, Harpenden, England, assignor to Imperial Chemical Industries Limited, London, England, a corporation of Great Britain Application August 24, 1954, Serial No. 451,865' Claims priority, application Great Britain August 28, 1953 Claims. (Cl. 18--8) l This invention provides an improved method and apparatus for melt-spinning artificial iilaments, particularly A high, being of the order of 2000 lb. per square inch. This pressure is generated either by a screw or, more usually, a gear metering pump which feeds the melt to the spinning pack. As spinning proceeds the hydraulic pressure inside the pack increases. Under these high pressures leaks of the melt are liable to develop between the components of thel spinning pack, the hydraulic pressure of the melt tending to force the components apart. This tendency to leak is aggravated by the tendency of gasket material to creep under mechanical stress.

I now provide a method ot melt-spinning using a spinning pack assembly wherein these undesirable leaks of the melt are virtually eliminated, even during prolonged use and which has the added advantage that the spinning pack can be dismantled and reassembled easily and quickly.

According to my invention I provide an improved method of melt-spinning utilising a spinning pack wherein the hydraulic pressure of the melt inside the pack acts to seal some or all the joints between the components of the pack.

My invention also provides an improved melt-spinning apparatus comprising a spinning pack, some or all of the components of said spinning pack being capable of limited relative movement under pressure, so that the hydraulic pressure within the spinning pack acts to close some or all the joints between the components of the spinning pack, and means for feeding molten material to said spinning pack, under pressure.

The spinning pack components oder a large internal surface to the viscous melt inside the spinning pack assembly and are subjected to a high hydraulic pressure. The pressure is transmitted to the gaskets or similar jointing devices between the various components and is proportionally magnilied when the area of the joints is small compared with the area of the surface of-the component in contact with the melt, so that the gaskets or similar jointing devices are compressed further with rising pressure.

The drawing illustrates but does not limit the scope of our invention.

Fig. l'is a diagrammatic section through a spinning pack.

The spinning pack assembly comprises the cylindrical rsf"ice l container 1 of circular section which is provided with a shoulder 2 at its lower end. The shoulder 2 supports a gasket 3 (shown uncompressed), a spinneret 4, .a bridge plate 5 with channels 6, distribution plate k7, ganzes 10, sand pack 11 and upper distributor plate-12. The distributor plate 12 is attached by legs 1 2 to a pack lid 13, which rests on a ange 14, beneath a' gasket 15 (shown uncompressed) under a thread lock ring 16.v The parts of the pack are tted intov the barrel in the order listed and the lock' ring 16 tightened on the lid 13.

During melt-spinning, the melt ispumped by a gear lpump (not shown) into the pack via the entry port 17.

The pressure of the melt tends to lift the lid 13 against the gasket, thereby compressing it'against the ring 16. The melt iiows through the pack from the plate 12 to the spinneret 4 and the components are all forced by the hydraulic pressure against the spinneret 4, which compresses the gasket 3. Thus, the hydraulic pressure acts to seal the ljoints where melt might escape from the pack. The 'build-up of hydraulic pressure during spinning compresses the gaskets further and seals the joints more tightly.

To clean the pack when spinning is completed `and the hydraulic pressure released byl stopping the pump, the ring 16 is unscrewed and the components removed from the barrel. Thus, the process .of dismantling and relitting is essentially quickv` and simple.

In the drawing a cylindrical containery of circular section is illustrated. Such ashaped container is preferred because ot' its symmetry, ease of manufacture and cleaning, and the tact that the various other components of the spinning pack can easily bemade and fitted into such a container. Containers of other shapes may be used, if desired.

It is preferred that that part of the container whichencloses the other components of the spinning pack, should be in one piece to obtain the full advantage of our invention. If desired, however, this need not be so and the flange 2 for example, could be bolted, threaded or otherwise attached to a cylindrical tube.' In such a case care must be taken to avoid leakage round the joint.

The pack illustrated is one in which entrance of the melt is from the side. This enables both the gasket 15 at the top of the pack and the gasket 4 at the bottom of the pack to be subjected to pressure by the movable components. With certain spinning apparatus a side entry for the melt may not be possible, the melt coming vertically downwards into the pack, through the pack lid 13.' In this case it is preferred that the pack lid should not be movable but should be rigidly fixed in position before spinning starts. Care must be taken to ensure that this rigid joint does not leak under the high melt pressures involved.

The flat circular gaskets shown in the drawing may be replaced by gaskets of different section e. g. triangular section, if this assists the sealing of the mating surfaces. Any heat resistant material may be usedfor the gaskets, which does not tend to disintegrate under heat and pressure.

Using the method and apparatus of my invention the nuisance of leakage due to gasket creep is minimised (because the pressure on all jointing devices is continu- 3 continuously increasi t rg hydraulic pressure during spinning.i What I claim is: 1. An improved melt-spinning apparatus wherein all vthe pressure-resistant joints are sealed bythe hydraulic ,pressure of the melt comprising a spinning pack and a ductvfor transmitting melt thereto and connected therewith, said spinning pack comprising a vertical container having an inner wall and an annular flange at its lower end projecting inwardly, an annular gasket of relatively small cross-sectional area supported on said ilange, at least one other component of the spinning pack being loosely mounted in operative position in said container and resting on said gasket, said one other component being of relatively great cross-sectional area and extending substantially across the inner diameter of the pack, said inner wall being unbroken from said gasket to said duct and a pack lid closing the upper end of said container.

2. The apparatus of claim 1, in which the gasket is ldirectly below a spinneret, said spinneret being a component of said spinning pack.

3. An apparatus according to claim 1, wherein the duct enters the container horizontally below the pack lid, and the pack lid is capable of limited vertical movement against a gasket, mounted above the pack lid and between itand a rigid structure, whereby the vertical movement ,of the pack lid is caused by the hydraulic pressure of the melt.

`4. A spinning pack assembly for melt spinning including a tubular housing opened at at least one end, closure means engaged to the other end of said housing for sealing this end, a radially inwardly directed annular ange means joined to said housing adjacent said one end thereof, internal removable components including a spinneret assembly loosely mounted in operative position in said housing intermediate said closure means and said flange means for axial movement therein, an annular compressible seal sandwiched in between said ilange Ymeans and said spinneret assembly, and means including a duct for introducing a melt under pressure into said housing intermediate said closure means and said spinneret assembly so that the pressure of the melt will operate to eiect relative movement of said spinneret assembly toward said flange means thereby compressing said seal.

5. The structure dened in claim 4 wherein said closure means includes: an annular, radially inwardly directed member joined to said housing, a radially inwardly directed flange on said housing disposed adjacent to and axially inwardly of said member, a disc-like element loosely disposed in said housing intermediate said member and said last-named flange for axial movement therein, and an annulaicompressible seal intermediate said element and said member.

References Cited in the iile of this patent UNITED STATES PATENTS OTHER REFERENCES Rayon & Textile Monthly, February 1936 (page 52 (92)) relied on.

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