Batch exhaustion process

Batch (Exhaustion) Processes. In jigger dyeing, the dyebath is charged with all the chemicals, and the dye and salt are added in steps at the desired temperature. After about six passages (or 60 min), dyeing is completed by rinsing and oxidation. 

Dyeing is carried out either as a batch exhaustion process, or as a continuous impregnation and fixation process. In exhaust dyeing, all the material is in contact with all the dye liquor from which the fibres absorb the dyes. The dye... 

Exhaustion Process. In batch dyeing, the preferred mode depends on the type of dyeing equipment, the type of material to be dyed, and the solubility and affinity of the dyes. The dye is dissolved in hot water and added to the dyebath. The electrolyte is added either during heating of the bath or after attaining the optimum dyeing temperature. The material is dyed at 80-90°C. Exhaustion is completed, if necessary, at somewhat lower temperature for a short time. After the dyebath has been drained, the fabric is quickly washed clear with cold water and generally subjected to aftertreatment (see Section 4.3.4). 

Batch Dyeing. Because of the low substantivity of leuco esters of vat dyes for cellulose, batch processes (exhaustion processes) are rather unimportant. 

The above equations are applicable strictly to batch (exhausted) dyeing processes only. Generally, continuous dyeing results in lower emissions than batch dyeing because of the... 

Batch processes deserve special consideration since, after each run, the entire treatment bath containing all auxiliaries and residual finishing compounds (e.g. dyes, finishes) is discharged to the sewer. Conventional exhaust processes thus... 

It is clear that the aim of pharmaceutical research is to achieve zero defects and zero batch rejections, and this can be verified by process validation. One must bear in mind that exhaustive finished testing of product is not a substitute for in-process controls and process validation. 

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