Abstract: An apparatus for treating a tow of filaments with a fluid, the apparatus forming a tow path therethrough and having a pair of guide surfaces positioned on opposite sides of the tow in series with each other in such a manner that the two path has at least two bends. Fluid nozzles associated with each of the guide surfaces are positioned in such a manner that fluid from these nozzles flows in layers along the guide surfaces and passes through the tow at the bends in the two path. This apparatus is capable of treating a tow under little or no tension, so that it can be used to anneal and shrink tows of certain filaments. The moving fluid advances the tow through the apparatus.

Abstract: The method of applying a finish to a tow of filaments, wherein the tow is advanced along a path through a housing having at least two bends in opposite direction to each other and passing a liquid containing a finish along the walls of the housing to the inside corners of the bends. The stream of liquid has a sufficiently high velocity that it clings in layers to the walls of the housing to the inside corners thereof, the bends being sufficiently great that the stream will separate from the walls of the housing and pass through the tow at a high velocity.

Abstract: The method of annealing a tow of acrylonitrile-containing filaments, wherein the tow is advanced along a path through a housing under tension less than the shrinking tension of the tow, the path having at least two bends in opposite directions to each other, and passing steam along the walls of the housing to the inside corners of the bends, the steam having a sufficient velocity that it clings in layers to the walls of the housing to the inside corners thereof, the bends being sufficiently great that the steam will separate from the walls of the housing and pass through the tow at a tow-forwarding velocity at the inside corners.