Abstract: The invention describes a low tension relax process and corresponding apparatus, wherein a tension gate is incorporated into a relax zone in a yarn production process. The tension gate can be anything that produces a drag on the yarn threadline such as an air drag device, a liquid drag device, or a solid surface contact drag device, or a combination of these. A tension gate is a device which when used in a relax zone has an outlet yarn tension greater than the inlet yarn tension thus creating a tension differential. The tension gate provides a tension differential of at least 5 mg per denier. A relax zone is typical found in a spin-drawing process, a draw-twisting process, a draw-winding process, or a draw-bulking process. The invention describes a yarn making process with a tension gate in the relax zone wherein the tension gate creates a tension differential on said yarn of at least 5 milligrams per denier.

Abstract: An apparatus and process for the continuous manufacture of high stress, high denier industrial yarn spun from polyethylene terephthalate polyester. A control system continuously measures melt viscosity of the polymer both at the outlet from a polymerization zone and at a downstream location adjacent a manifold immediately preceding a plurality of spinnerettes through which the polymer is drawn into filamentary material. Adjustments are continuously made to a meaningful operating condition within the polymerization zone, such as the magnitude of the vacuum therein, whenever IV inferred from operating data strays from a pre-established level. Adjustments are also regularly made at discrete short term intervals, for example, minute by minute, whenever viscosity at the outlet from the polymerization zone strays from the pre-established level.