Sealed Indigo Dyeing Chambers for Lower Chemical Use
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional denim dyeing processes for warp chains using indigo and other colorants are inefficient, requiring multiple vats, high sodium hydrosulphite consumption, and resulting in significant yarn rejects and increased costs due to the need for precise chemical management and lengthy oxidation processes.
Innovation Solution
A continuous dyeing device with at least two hermetically sealed dyeing compartments and a squeezing element, equipped with heating/dehydrating means to enhance colorant diffusion and absorption, operating in an inert environment to reduce hydrosulphite and soda consumption, and capable of handling various colorants like sulphur, indanthrene, and reactive dyes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple dyeing vats (8 or more) are used in traditional continuous dyeing processes, then the color intensity and solidity are improved, but the device complexity and production costs increase significantly
Solution Approach 1:
The patent combines multiple dyeing functions into a single integrated dyeing vat with improved circulation and impregnation mechanisms. The dyeing bath is equipped with enhanced mixing systems and multiple impregnation zones that allow achieving the color intensity and solidity previously requiring 8+ separate vats, thereby reducing device complexity while maintaining manufacturing precision
Solution Approach 2:
The patent modifies key process parameters including extended immersion times, optimized chemical concentrations (sodium hydrosulphite and caustic soda ratios), and controlled temperature profiles within the dyeing vat. These parameter changes enable achieving dark blue denim with high solidity in fewer vats by improving the efficiency of each dyeing stage
2Reliability
If sodium hydrosulphite is continuously added to maintain reducing capacity in open vats, then the dyeing capacity is maintained, but the loss of substance and production costs increase
Solution Approach 1:
The patent employs a closed dyeing system with an inert or controlled atmosphere that prevents premature oxidation of sodium hydrosulphite by atmospheric oxygen. This eliminates the need for continuous chemical replenishment to counteract oxidation losses, thereby reducing substance loss while maintaining reliable dyeing capacity throughout the process
Solution Approach 2:
The patent implements a closed circulation system where the reducing agent remains continuously effective without interruption or degradation from air exposure. The controlled environment ensures the sodium hydrosulphite maintains its reducing capacity throughout the entire dyeing process, eliminating the need for periodic reintegration and reducing overall consumption
3Manufacturing precision
If lengthy oxidation stages (60 seconds exposure to air) are used after squeezing, then the color tone is darkened and intensified, but the production time and productivity are reduced
Solution Approach 1:
The patent optimizes oxidation parameters by controlling temperature, humidity, and chemical environment during the oxidation stage. By adjusting these parameters, the oxidation process achieves complete color development and darkening in reduced time, maintaining manufacturing precision while improving productivity through faster cycle times
4Manufacturing precision
If the dyeing line length is increased to accommodate multiple vats and oxidation zones, then the color intensity is improved, but the yarn rejects and start-up losses increase
Solution Approach 1:
The patent integrates multiple dyeing and oxidation functions into a compact, continuous process within a reduced line length. The merged system maintains color uniformity and intensity through improved bath circulation and controlled oxidation zones, while the shortened line reduces yarn exposure to variability and minimizes rejects during batch transitions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces yarn rejects and equipment costs, enhances colorant diffusion and absorption, and allows for more efficient and flexible dyeing of small batches, while minimizing hydrosulphite and soda usage, thereby improving the overall dyeing process efficiency and adaptability.
Implementation Method 1
at least one means for heating and/or dehydrating the yarn to increase the diffusion of the colorant in the fiber and the pick up of the colorant
Implementation Method 2
as a result of the bath/air contact, the sodium hydrosulphite reacts with the oxygen in the air losing its reducing capacity towards the indigo
Data Source
AI summary
A continuous dyeing device and related processes using indigo and/or other colorants for warp yarn chains and/or for fabrics, equipped with at least a first and a second dyeing compartments containing dyeing baths, the first and second dyeing compartments being enclosed, at least partially, in a hermetically sealed chamber. The device also includes at least one squeezing element interposed between the two dyeing compartments and a plurality of cylinders for heating and/or dehydrating the yarn and or the fabric, thereby increasing the diffusion and the absorption of the colorant. The cylinders are positioned downstream of the first dyeing compartment and squeezing element.