Alkali Dosing Profiles and Mass Transfer in Jet Dyeing
Controlled progressive alkali dosing matches jet fabric loop velocity to eliminate surface fixation spikes and secure level shade fixation on cellulosic cloth.
Linear Dosing
Constant Injection
Chemical delivery methods that provide a steady flow of additives into a process liquor at a fixed rate over a defined period ensure uniform exhaustion in dyeing machines. Linear dosing prevents the sudden shifts in pH or concentration that cause uneven colour distribution on the fabric surface. By spreading the addition of salt or alkali evenly throughout the cycle, the system promotes a slow and controlled migration of dye molecules into the fibre core.
Machine Control
Automated pumps manage the volume of liquid transferred from the addition tank to the main vessel. Unlike progressive dosing, where the speed increases over time, linear dosing maintains a flat profile that is easier to replicate across different machines. This consistency is necessary for maintaining the levelness of sensitive shades like pale greys or light tans where any patchiness is immediately visible to the eye.
Dye Levelness
Uniformity across the width and length of a fabric roll depends on the predictable arrival of chemicals. When a technician programs a linear dosing sequence for thirty minutes, the risk of localized over-fixation is reduced. This method is particularly effective for heavy fabrics where the liquor circulation time is long compared to the reaction speed of the dyestuff.
Practical Limitation
Systems using this approach may require longer overall cycle times compared to accelerated methods to ensure the same degree of penetration.