Airflow Porosimetry Calibration Parameters for Unhackled Dew-Retted Long Flax Bundles
Precise airflow porosimetry of unhackled dew-retted flax requires axial strick alignment, controlled 196 kPa compaction, and 12 percent regain normalization.
Wall Effect Channeling
Flow Disruption
Liquid bypass occurring at the interface between a fiber mass and the rigid walls of a processing vessel reduces the efficiency of chemical treatments. This wall effect channeling allows the dye liquor or bleaching solution to flow more rapidly through the low resistance gap at the edge rather than through the dense center of the flax package. It results in uneven color distribution and incomplete processing of the fibers in the middle of the batch.
Treatment Variance
Variations in fluid velocity create a temperature gradient across the width of the treatment tank. The wall effect channeling causes the fibers near the boundary to receive more chemical exposure than those in the center. To mitigate this, mill engineers use flexible seals or adjustable baffles to force the liquid back into the fiber bed.
Precise packing of the flax sliver into the canisters also helps to minimize the peripheral gaps. If the channeling is not controlled, the outer layers of the yarn may become over-processed and brittle while the core remains under-scoured.
Uniformity Requirement
Success in high volume linen production depends on achieving a homogenous result across every meter of fabric. Consistent pressure across the entire cross section of the vessel prevents the fluid from taking the path of least resistance.