Abstract: A melt spinning pack, including a pack case, a spinneret having many spinning holes positioned at the bottom of the case, a pack cap having a polymer introducing hole at the center positioned at the top of the case, and a flow arranging plate having many flow arranging holes with restricted portions reduced in cross sectional area compared to the inlets of the holes positioned between the spinneret and the pack cap, satisfying the requirement that the contraction percentage R be 50% or less, respectively contained in the case.

Abstract: A heat treatment apparatus for yarn including a plurality of heat treatment apparatuses provided for a plurality of spindles, respectively, disposed at horizontally spaced intervals. The heat treatment apparatus provided for each of the spindles, includes a heat treatment tube through which at least one yarn passes, and a heat insulating jacket to surround the tube. An orifice having a throttling function is provided upstream of a part which provides communication between the heat insulating jacket and the heat treatment tube, while a nozzle for injecting a heated fluid is provided in the heat treatment tube downstream of the communication part. The throttling orifice is arranged to have a fluid resistance greater than the fluid resistance of the nozzle.

Abstract: This invention relates to a method and apparatus for producing a polyester fiber which cools a plurality of molten polyester fibers from a spinnert 2 to a temperature below a glass transition point, then takes up the fibers by a non-heating first godet roller at a take-up speed less than 4,000 m/min, heat-stretching the fibers between the first godet roller and a non-heating second godet roller 10 inside a normal pressure steam atmosphere (first heat-treating device 8) higher than the glass transition point of the polyester fiber, and heat-treats the fiber by a pressurized steam atmosphere (second heat-treating device 9) higher than 105.degree. C.

Abstract: A system for producing a drawn yarn having a durable mechanical and thermal stability in practical use from a fiber-forming polymer by means of a single continuous process is disclosed. A yarn extruded from a spinneret is first introduced into a liquid bath for cooling and subsequently to a hot chamber filled with a pressurized steam for heat-treatment, in which the yarn is drawn against a resistance caused by the liquid bath. The vessel of the liquid bath is provided with a yarn exit path adapted to allow the passage of the yarn but inhibit the leakage of the liquid and to remove a concomitant liquid from the yarn. The hot chamber is provided with inlet and outlet paths for the yarn also adapted to allow the passage of the yarn but inhibit the leakage of the steam. The system is suitable for producing for industrial use a yarn composed of thicker individual filaments.

Abstract: A process and an apparatus for simultaneously drawing and false-twisting a thermoplastic synthetic yarn, in or by which an undrawn or a partially drawn yarn is drawn under a dry hot condition in a condition of the yarn being false-twisted by twist transmitted from a false-twister and immediately thereafter heat-set under a wet hot condition prior to untwisting.The apparatus includes a yarn heater, which comprises a dry heater disposed on the side of a feeding device for the undrawn or partially drawn yarn and a wet heater on the side of a false-twister along the yarn passing direction.