Abstract: Synthetic yarn to be bulked and heat set is supplied to a plurality of ovens in coiled form and is subjected to an even hot flow of dry gaseous fluid to bulk and heat set the yarn as it passes successively through the bulking oven and the heat setting oven. Safety controls are provided to prevent damage to the yarn when the conveying system is shut down and the yarn is being conveyed through the system.

Abstract: A method of producing surface height patterned materials by application of streams of pressurized, heated fluid into surface areas of a relatively moving material having thermally modifiable surface components. The heated fluid streams are selectively activated and deactivated in accordance with pattern information to strike selected surface areas of the material to thermally shrink and compact the surface areas by a desired amount. Heated fluid stream flow is controlled by use of cooler pressurized fluid which is selectively directed into the heated fluid stream flow to block the same from striking the surface of the moving material. The temperature of selected of the heated fluid streams striking the material is controllably varied by rapidly introducing small amounts of cooler fluid which blend into the heated streams to correspondingly vary the height reduction of the surface of the material.