Abstract: Apparatus including a vessel for dyeing cellulose fibers in a bath containing a reactive dyeing agent and an alkaline material for fixation thereof, a pump for progressively adding the alkaline material to the bath in a continuous and automatic manner over a predetermined time interval, and an electronic control system for regulating the amount of alkaline material added, the amount being limited initially and increased in a final phase of addition until a sufficient amount is added to fix the dyeing agent. The pump is of the reciprocating piston type, the length and frequency of the strokes thereof being regulated by the control system.

Abstract: Method for dyeing cellulose fibers in a bath containing a reactive dyeing agent and an alkaline material for fixation thereof, by progressively adding the alkaline material to the bath in a continuous and automatic manner over a predetermined time interval, the amount of alkaline material added being limited initially and increased in a final phase of addition until a sufficient amount is added to fix the dyeing agent.