[0001] This invention relates to a distributor disc for molten thermoplastic material fed
to a spinning head for spinning plastic masses, to obtain synthetic yarn. The mass
to be spun is fed onto said distributor disc, so that in flowing over its conical
crown-like surface it is distributed uniformly by a plurality of concave radial grooves
in spoke arrangement, which converge with, and expel the molten thermoplastic material
into, grooves in the outer circumferential edge of the disc.
[0002] It is known to produce yarn from thermoplastic masses, such as polyesters, polyamides
etc., by the extrusion spinning method. In this respect, the mass of thermoplastic
synthetic material to form the yarn is preferably fed by an extrusion press along
a central channel to the inlet of a spinning head, from which the yarn emerges through
sized nozzles to be collected on winding devices.
[0003] The starting polymer in the solid state passes initially through a heating process
in which it is melted to the liquid state, after which it is fed by an extrusion press
or any other suitable member to the actual spinning block.
[0004] This spinning block comprises in practice a disc for distributing the molten polymer
entering the underlying filter block. In known constructions, this molten polymer
distributor disc has substantial drawbacks, related to the formation of static molten
masses, ie residual material which solidifies in the corners between the wall of the
spinning block and the surface of the distributor disc. The residual material which
solidifies during spinning on the one hand contributes hydrodynamic resistance to
the flow of the molten polymer, and on the other hand after a more or less lengthy
period of operation reduces the passage cross-section, to finally block the spinning
process.
[0005] Again, any residues which disintegrate and reach the seats of the underlying spinning
nozzles can negatively influence the spinning process underway. The applicant, after
careful research, has conceived a distributor disc for molten thermoplastic material,
the subject of the present invention, which obviates the aforesaid drawbacks by an
original solution which makes it impossible for any residual molten material to solidify
by stagnancy. Said distributor disc for thermoplastic material comprises a conical
crown-like surface in which there are provided a plurality of concave radial grooves
with their cross-section gradually increasing from the centre to the periphery at
the grooved outer circumferential edge. Said concave radial grooves are arranged as
spokes uniformly distributed over the conical crown-like surface of the disc, each
concave radial groove converging with and opening into a respective groove in the
grooved outer circumferential edge. Said grooves in the outer circumferential edge
are of substantially rectangular shape with sufficiently rounded corners.
[0006] The present invention will be more apparent with reference to the accompanying drawing,
which shows one embodiment of the claimed distributor disc.
[0007] The figure of the single accompanying drawing shows a schematic section on a vertical
axis though a spinning block comprising the distributor disc for molten thermoplastic
material of the present invention.
[0008] The polymer in the molten liquid state is fed under pressure in the direction 9 into
the central entry duct 3 of the spinning block 1. All this is well known to the expert
of the art. As is also known, the path for the molten polymer entering the spinning
block 1 must be made fluid-tight by gaskets 11 of suitable material. The molten polymer
flows under pressure through the central duct 3 in the block 7 and onto the conical
crown-like surface 6 of the distributor disc 8. Said molten polymer is distributed
circumferentially and flows uniformly along the direction 2 within the circumferential
space between the surfaces 6 and 4. On said surface 6 the molten polymer is obliged
to enter concave radial grooves 5 in spoke arrangement, said radial grooves 5 being
concave and with their cross-section gradually increasing in size from the centre
of the conical surface 6 to the periphery at the grooved outer circumferential edge
of the distributor disc 8.
[0009] The cross-section gradually increases in size in order to maintain the circumferential
passage section for the molten polymer substantially constant. This latter flows uniformly
into the discoidal space 14, to pass through the filter block 10 and then into the
underlying discoidal space 14, from which it leaves to pass through the plate 15 via
the sized passage holes 18, from which it emerges to flow firstly into the discoidal
space 20 and then through the sized nozzles 16 in the plate 19. From the plate 19,
which represents the actual spinning element, the molten polymer leaves in the direction
12 in its final spun yarn form to be collected on an underlying winding unit (not
shown).
[0010] The description is given by way of example only, it being apparent that modifications
in terms of detail can be made to the distributor disc according to the present invention,
but without leaving the scope of the inventive idea as claimed hereinafter.
1. A distributor disc for molten thermoplastic material feeding a spinning head for spinning
plastic masses, to obtain yarn or similar filiform elements, the molten mass being
fed to said disc by a screw press or pump via a duct delivering to the centre of said
disc a metered quantity of spinning mass, which flows over the curved conical crown-like
surface of the disc and into the underlying filter block, to pass under pressure to
a plate carrying a series of nozzles as the actual spinning implement, said distributor
disc being characterised by comprising in its conical crown-like surface a plurality
of concave radial grooves with their cross-section substantially in the form of a
circular arc which gradually increases in size from the centre to the periphery at
the grooved outer circumferential edge.
2. A distributor disc for molten thermoplastic material feeding a spinning head as claimed
in claim 1, characterised in that the concave radial grooves are arranged as spokes
uniformly distributed over the conical crown-like surface of the disc, each concave
radial groove converging with and opening into a respective groove in the grooved
outer circumferential edge.
3. A distributor disc for molten thermoplastic material feeding a spinning head as claimed
in claim 2, characterised in that the grooves in the outer circumferential edge are
of substantially rectangular shape with sufficiently rounded corners.
