Pneumatic Force
Compressed air force measured in megapascals or bar propels the filling yarn into the weaving shed at the start of each insertion cycle on air-jet looms. In linen weaving, main nozzle pressure must be calibrated precisely to overcome the high friction and irregular hairiness of flax yarns. Insufficient pressure causes short picks or insertion failure, while excess pressure damages delicate flax strands or causes yarn bucking.
Pressure settings directly control initial pick velocity.
Insertion Mechanic
Acceleration of the weft tip depends on air velocity exiting the nozzle orifice during the valve opening window. Flax yarns present unique aerodynamic challenges because spun linen surfaces possess uneven friction profiles and loose surface fibrils. To achieve reliable insertion across wide loom widths, mill technicians balance main nozzle pressure with relay nozzle timing along the profile reed channel.
Higher pressure increases air consumption and energy costs, prompting weavers to find the minimum effective pressure that maintains stable pick trajectory. Automated pressure regulators adjust compressed air supply dynamically to offset fluctuations in main air line pressure.
Operating Boundary
Pressure limits are bound by yarn tensile strength and air supply capacity. Exceeding recommended pressure thresholds causes filament stripping or yarn breakage inside the nozzle tube. Standardized pressure curves match specific linen yarn counts to ensure consistent filling insertion without yarn degradation.
