Abstract:
In conjunction with a heat-set apparatus (10) for carpet yarns (17) which incorporates a plenum chamber (22) having a porous upper surface (22d) in combination with a forced draft system (33) for recirculating the heating medium throughout the length of the heat-set chamber (10), an improved design of the plenum chamber (22) and the distribution of the medium to compensate for a temperature gradient which has heretofore existed in the heat-set chamber (10) resulting from the introduction of cooled yarn (17) into the chamber (10). Such temperature gradient has been the cause of dye streaking which occurs when the yarn (17) is subjected to relatively cooler temperature adjacent to the entrance to the heat-set chamber (10) when the machine is stopped.