Patent GB-783522-A (GB)
Title: Improvements relating to apparatus for the production of filamentary material by melt spinning
Inventor: HUNTER WILLIAM
IPC: D01D1/04
Filed: 1954-04-29
Abstract: Apparatus for melt-spinning comprises a vessel divided into an upper and a lower part by an upwardly facing internal conical surface sloping downwards to a single opening leading from the upper to the lower part, means for supplying solid filament-forming material within the upper part to the uppermost portion of the conical surface, and means for supplying heat to the conical surface to melt solid filamentforming material in contact therewith, the conical surface being formed with one or more protrusions extending individually or collectively completely round the axis of the conical surface, over the higher sides of which protrusions the downward slope of the conical surface is substantially reduced or reversed. The single opening may be centrally located, the conical surface converging downwards towards it at a low angle to the horizontal, e.g. 10-30 degrees. Alternatively the single opening may be an annular opening close to the wall of the vessel, the conical surface then converging upwards at a low angle, being supplied at its apex with solid material and being preferably carried on a support extending up the axis of the vessel.  In either case, the opening is preferably formed with a lip extending downwards into the lower part of the vessel, from which lip the molten filament-forming <PICT:0783522/IV (a)/1> material drains away.  The protrusions on the surface may be continuous ring-like protrusions (preferably two or more) encircling the axis of the conical surface, or may be discontinuous about the axis of the vessel, being arranged at two or more levels in such a manner that the protrusions at one level overlap the gaps between the protrusions at another level.  The conical surface may be the upper surface of a hollow tray through which a heating fluid is circulated, or may be the inner surface of a massive annular block of metal having electrical heating elements wound round the outside.  As shown, solid particulate filament-forming material in the conical top section 5 of a cylindrical vessel 4 is discharged through the annular gap 15 between the conical baffle 14 (supported by four horizontal arms 16 lodged at their extremities in four cleats 18 on the inner wall of the vessel) and the wall of the cylindrical section 13 of the vessel and drops to the periphery of the upper surface 22 of the heated hollow conical tray 19.  The material during fusion by contact with the surface 22 is prevented from sliding down the surface while still in the solid state by the concentric ridges 23, while the fused material flows over the ridges down the surface 22 and through the opening 21 communicating with the bottom section 7 of the vessel.  The fused material dripping from the downwardly projecting lip 26 of the opening 21 collects in a pool 11 in the lower part of the section 7 of the vessel whence it is drawn away through passage 8 by a spinning pump 9.  Heating fluid enters the interior of the hollow tray 19 through a tangential inlet pipe 27 and leaves it through a tangential outlet pipe 28.  A current of an inert gas such as nitrogen is passed upwards through the vessel, entering through an inlet pipe 31 which is coiled round the bottom of the vessel at 32 to preheat the gas and is withdrawn through an outlet 34 at the top of the vessel.  The entire vessel and the heavy metal block 12 containing the pump 9, passage 8 and a filter and spinning jet (not shown) are surrounded by a layer of heat-insulating material 35 and rings 36, also of insulating material.  The conical top section 5 of the vessel is provided with a removable cover-plate (not shown). Extending through the side wall of the section 7 is a level-indicating electrode 29 in the form of an insulated conductor dipping into the pool of melt 11 and connected to the walls of the vessel through a circuit indicating the depth of the immersion of the tip of the electrode in the pool of melt, which has an appreciable electrical conductivity.  The circuit may also be arranged to control the supply of heat through the tray 19 (by controlling the pressure in a boiler supplying a hot vapour to the tray) and thus maintain the pool 11 at a constant predetermined level.