Water Jet and Reed Profile Interaction
topic
Water-jet looms use flat reeds without the profiled channel of air-jet reeds because the water jet maintains a coherent stream across the full shed width without lateral diffusion guidance from reed channel walls, relying instead on the surface tension and inertia of the water stream to maintain yarn trajectory across the shed, with the interaction between water jet coherence and warp yarn contact determining the insertion reliability and warp damage risk from the water stream impacting warp ends at shed boundaries.
Role
Defines the aerodynamic and hydraulic mechanism governing yarn trajectory in water-jet insertion, with jet coherence maintenance across the shed width being the critical physical requirement that limits water-jet to fabric widths below 330 centimetres where jet dispersion does not become sufficient to cause insertion reliability problems, and with the simpler flat reed design being a cost and cleaning advantage compared to the profiled reeds of air-jet systems.