Abstract: An apparatus for treating yarn with fluid which is designed to allow a yarn consisting of an as-spun multifilament to run between first and second components which have inner walls arranged facing against each other with a specified gap provided between them and to interlace the filaments by a fluid in order to provide the yarn with coherence. The first and second components are provided with at least one fluid conduit which is opened in their inner walls. These fluid conduits form a yarn treating region with axes of the fluid conduits and the inner walls of the first and second components. These fluid conduits are provided between the axes of the fluid conduits with a specified distance between them in a section which is substantially orthogonal with a running direction of the yarn and are arranged aslant so that the fluid ejected from the fluid conduits is directed to the yarn treating region.

Abstract: Apparatus for imparting a good cohering property to a multifilament yarn by applying a continuous main jet stream of a fluid to a running multifilament yarn in a yarn treating zone, while impinging a subsidiary jet stream having a discontinuous pressure wave against the above-mentioned continuous main jet stream so as to expose the running multifilament yarn to the impinging jet stream having a resonance sharpness of at least 2 at the position outlet aperture of the yarn treating zone.