Melt spinning apparatus

摘要

A melt-spinning apparatus comprises a feed passage leading to a melting unit which has a number of hollow individual heater members, e.g. hollow cores or pins, projecting from a support along the line of feed and spaced closely so as to impede passage of solid material whilst permitting passage of molten material to an outlet leading to the spinning pump. The heater members are heated by circulation of fluid through the interior thereof. The heater members may be set in a concave or convex support, preferably convex, and are preferably arranged so that their tips all lie in one plane. The solid material, e.g. polyethylene terephthalate in chip form, is preferably fed under pressure by a screw conveyer whose pressure is kept constant by a compressed spring or pneumatic piston which allows the screw to retract axially under excessive pressure. One example of a melting unit is shown in Fig. 4, wherein the conical heating members 24 are mounted in a concave support 23 and are heated by fluid introduced at 27 which passes into the interior of each member 24 and out at 27A. Molten material passes through the outlet 30 which is restricted by member 28 to prevent the passage of unmelted chips. Fig. 9 shows a complete melt-spinning apparatus in which polymer chips are fed from a hopper 32 to screw conveyer 33, driven by motor and reduction gear 44, 43, thence to melting unit 31. The molten material passes on to spinning pump 37, filter pack 38 and spinneret 39. The melting unit is heated by passing heating fluid in at 40 and out at 41; the hopper and barrel 34 of the screw conveyer may also be heated so as to pre-heat the chips before they reach the melting unit. The screw conveyer 33 rises against compression spring 35 in the event of excessive pressure build up. Fig. 10 shows a further example of a melt unit in which the pointed hollow heating elements 11 are mounted in a convex support 12 so that their points lie in one plane. Heating fluid enters at 12B, passes through tubes 11A into the interior of each heating element, into chamber 12C which opens into the hollow jacket 13A, and out at 16. Molten polymer passes through peripheral cavity 14 to outflow duct 15. The heating elements 11 may be arranged radially and their diameters may decrease towards the outside of the melting unit, or they may all be of the same diameter and spaced equi-distantly from one another.