Dyeing vessel

The cheeses, cones, or other packages are loaded onto the perforated vertical tubes of the carriers (Fig. 13.14(a) and (b)) which drop into aseating in the dye vessel, connected to a centrifugal pump which circulates the liquor in a manner illustrated diagrammatically in Fig. 13.15. When the dye vessel is open to the atmosphere it is only practical to have circulation from inside to outside, because centrifugal pumps are less eflicient when used as... 

In order to obtain a two-way flow the dye vessel must be closed and capable of withstanding pressures of up to 20 lb per o lhe dyehig... 

On account of the readiness with which both the sulphur dyes and the alkali sulphides liberate hydrogen sulphide, the use of rnetal dye vessels, other than stainless steel, can be dangerous. Machines composed of copper or containing this metal in the form of fittings should never be used. Most metallic sulphides are insoluble and black or dark in colour and will stain the goods and flatten the shade. 

Transfer 0.5 mL of the gelatin solution to the reactive dye vessel. Invert a few times to frilly dissolve the dye. Stir the reaction mixture for 1 h at room temperature in the dark using a magnetic stirrer and the stir bar already provided in the vial. 

Top dyeing n. (1) The process of covering with an additional dye, not necessarily of the same color or class, to obtain the desired shade. (2) Fiber in top form is placed in cans and dyed in a batch-dye vessel with reverse cycling capability. An expensive process that is used primarily for fancy yarns. 

Max Load per dyeing vessel Average dyeing time Test performed... 

The dyeing machines are equipped with maximally 3 dyeing vessels and are connected to a COj recovery and supply imit. These three dyeing vessels are able to dye textile simultaneously, but sequentially pressurized or depressurized. A dyeing cycle is divided into five steps ... 

Step 0 Atmospheric - the dyeing vessel is not imder pressure Step 1 Pressurization - the dyeing vessel will be filled with CO ... 

Once the dyeing cycle is complete, the CO is gasified to recover the excess dye. Unburdened, the clean CO cycles back into the dyeing vessel for reuse, a manoeuvre that saves energy, water, and the heavy metals that comprise much of the toxic runoff into our planet s polluted waterways, according to DyeCoo. The process isn t without its limitations, however. DyeCoo is currently only able to dye scoured (or prewashed) polyester fabric, although the company notes that it s working on a version that will dye unscoured fabric, as well as reactive dyes for cellulosie textiles made from plants. 

Key words dyeing, dyes, textile fibres, dyeing quality, dyeing rate, levelness, dyeing vessels, package dyeing, dyeing automation, exhaustion profiles. 

Other designs for the vessel have attracted some attention. One of these designs introduces a horizontal dyeing vessel by OBEM. ... 

A typical schematic representation of a package dyeing vessel can be seen in Fig. 1.3. 

Some package dyeing machines are fitted with an external sampling tank. This is used to identify the problems that may occur during the dyeing. However, despite the care taken, it is extremely difficult to reproduce the exact conditions of the dyeing vessel, and therefore the diagnostics are not necessarily correct. Other methods have also been used, which are described elsewhere. ... 

Together with the continuity equation, they form a system of equations that have to be solved considering the proper initial and boundary conditions. The simulation results provided information on the static pressure and velocity distribution in every part of the dyeing vessel. 

Table 7.1 General specifications of a pilot-scale package dyeing vessel...

A PID system may be used for the control of the heating/cooling. The heat capacity of the heaters and the effect of the main circulating pump should be taken into account and the cooling rate of the machine should also be calculated. The response time of the system should also be measured. As indicated, the system described here is capable of controlling temperature in the dyeing vessel to 0.2 °C. 

A bypass pipe connection may be used to isolate the mixing tank from the rest of the dyeing vessel in this way low liquor ratios can also be established. The fluid flow loop through the pipes, however, can be controlled by means of pneumatic valves that direct the fluid from inside to outside, or vice versa, of yam packages. This may be done with the aid of a four-way valve located at the base of the kier. A ventilator valve may be used to direct the liquid in the top of the kier to the mixing tank, and once the kier is full this valve is shut off. Valves may be controlled manually via a control box or via connections to the interface, which in the example in Table 7.2 are BlTs 0-5 of PORT B. All pneumatically operated ball valves on the machine may be fitted with doubleacting actuators. The actuators may be controlled by solenoid/spring spool valves (e.g. 5/2). The term 5/2 denotes a valve with five ports and two positions. 

A pH meter is often incorporated in modem dyeing vessels to determine changes in pH during the dyeing process. Since control of pH is critical in many apphcations, this section addresses the process in more detail. The methods for reducing the consumption of chemicals and energy in the dyeing industry are based on ... 

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