Heater for running synthetic yarns especially operating above yarn melting point

摘要

A heater for a group of running synthetic yarns (11) has a slot shaped channel (10) formed by opposing heating surfaces (12,13). Several yarn guides (6,7) are spaced along at least one of the surfaces (12,13) so that the threadlines run in a plane through the channel (10). The yarn guides (6,7) are arranged so that the yarns (11) contact each guide and give a curvilinear thread path through the heater channel (10). Preferably the guides can be fitted along one surface only with an arc shaped thread path or they can be alternately on both surfaces, giving a zig-zag path. The guides can be pegs attached to the surface at right angles to the thread path, or they can be raised swages on a carrier fitted into the heating channel. The guides can be circular or elliptical in section for minimum contact or, where longer contact is required, e.g. with polyamides, a rectangular section can be used. Heating is provided by cartridge heaters (8,9), both surfaces (12,13) being at the same temperature. The heater can have several independently heated successive zones at different temperatures, e.g. for drawing and relaxing. To assist stringing up and cleaning, one of the walls can be made movable through a mechanical, electric, pneumatic or hydraulic actuator.