Determining Venturi Nozzle Insert Sizing for Jet Dyeing Light Woven Fabrics
Determine light woven jet nozzle sizing by matching compressed rope cross-section plus forty percent liquor annulus area to prevent abrasion and creases.
Throat Diameter
Internal Geometry
Internal dimension measuring the narrowest cross-section of a jet dyeing nozzle assembly. The throat diameter determines fluid velocity and liquid pressure exerted on rope-form fabric passing through the dyeing cycle. Nozzle inserts feature converging conical profiles that accelerate dye liquor into a high-speed liquid stream at this narrowest point.
Matching this internal dimension to fabric rope thickness ensures efficient transport without mechanical clogging.
Hydrodynamic Pressure
Liquid acceleration through a restricted channel converts static pump pressure into dynamic kinetic energy. As liquor flows through a reduced throat diameter, fluid speed increases rapidly according to Venturi principles, pulling the fabric rope forward. Higher fluid speed increases liquid contact with yarn surfaces, promoting rapid dye liquor turnover and level color penetration.
Machine operators change nozzle inserts to adjust throat size when switching between heavy fleece and lightweight lining fabrics.
Fabric Clearance
Correct clearance between the fabric rope diameter and nozzle wall prevents structural damage. An oversized throat diameter reduces liquid flow velocity, causing fabric stagnation and tangling inside the machine vessel. An undersized opening compresses the fabric rope excessively, causing longitudinal friction marks, chafe marks, and rope creases along synthetic fabric surfaces.
Operational Limit
Nozzle wear from abrasive dyestuffs and high-velocity liquor gradually expands internal dimensions over time. Worn throat diameter profiles cause pressure loss across circulation pumps, requiring hardware replacement during scheduled maintenance.