Jacquard Repeat Length Priced as Card Time and Loom Hours
Pricing Jacquard repeat length requires balancing flat card preparation fees against loom hour rate increases caused by harness mass speed penalties.
Air Jet Shed Turbulence
Air Jet Shed Turbulence Measurement
Air jet shed turbulence is the aerodynamic disruption occurring within the weft insertion zone during high-speed pneumatic weaving operations. Operators record this phenomenon on the loom tuning log during baseline parameter checks for heavy linen yarn production. Rapidly expanding compressed air streams exiting the main relay nozzles collide with stagnant atmospheric pockets inside the channel.
Velocity differentials between the core delivery jet and surrounding boundary layers generate high-frequency pressure fluctuations across the reed line. These local pressure spikes deflect delicate long-vegetable-fibre filaments from their intended flight paths, causing premature contact with adjacent warp ends. Mechanical yarn fatigue accelerates when repeated pneumatic impacts force individual fibers outward from the parallel bundle before reed beat-up occurs.
Nozzle Pressure Drift
Compressed air delivery parameters dictate the stability profile of the pneumatic insertion corridor. Fluctuations in line pressure originate from compressor cycling variations and restricted filter housings upstream of the relay valves. Main nozzle timing intervals must match the rotational velocity of the main shaft within strict rotational tolerances.
Incorrect dwell settings permit residual vortices to linger inside the shed long after the pick has cleared the selvedge. Such residual vortex energy disrupts the smooth descent of the falling warp sheet during the subsequent shed closure sequence. Mill technicians adjust regulating valves until pressure decay curves match the specific weight parameters recorded on the lot acceptance certificate.
Warp Interaction Limits
High velocity airflow creates localized friction against adjacent warp threads during the transit phase. Unstable pneumatic profiles cause adjacent yarn segments to oscillate vertically beyond acceptable displacement thresholds. Dense flax yarns tolerate minimal lateral deflection before surface hairs raise and interlock with neighboring ends.
Warp tension settings on the loom beam must compensate for the disruptive force exerted by the moving airstream. Excessive aerodynamic disturbance forces the quality control inspector to downgrade the greige fabric classification from export grade to domestic utility standard.