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Dyeing Machinery And Dyeing Manipulations






Wool is dyed in a variety of forms, raw, loose wool; partly
manufactured fibre in the form of slubbing or sliver; spun fibres or
yarns, in hanks or skeins and in warps, and lastly in the form of
woven pieces. These different forms necessitate the employment of
different forms of machinery and different modes of handling, it is
evident to the least unobservant that it would be quite impossible to
subject slubbing or sliver to the same treatment as yarn or cloth,
otherwise the slubbing would be destroyed and rendered valueless.

In the early days all dyeing was done by hand in the simplest possible
contrivances, but during the last quarter of a century there has been
a great development in the quantity of dyeing that has been done, and
this has really necessitated the application of machinery, for hand
work could not possibly cope with the amount of dyeing now done.
Consequently there has been devised during the past two decades a
great variety of machines for dyeing every description of textile
fabrics, some have not been found a practical success for a variety of
reasons and have gone out of use, others have been successful and are
in use in dye-works.

#Hand Dyeing.#--Dyeing by hand is carried on in the simplest possible
appliances, much depends upon whether the work can be done at the
ordinary temperature or at the boil. Figure 10 shows round and oval
tubs and a rectangular vat much in use in dye-houses. These are (p. 041)
made of wood, but copper dye-vats are also made, these may be used
for all kinds of material--loose fibre, yarns or cloth. In the case of
loose fibre this is stirred about either with poles or with rakes,
care being taken to turn every part over and over and open out the
masses of fibre as much as possible in order to avoid matting or
clotting together. In the case of yarns or skeins, these are hung on
sticks resting on the edges of the tub or vat. These sticks are best
made of hickory, but ash or beech or any hard wood that can be worked
smooth and which does not swell much when treated with water may be
used. The usual method of working is to hang the skein on the stick,
spreading it out as much as possible, then immerse the yarn in the
liquor, lift it up and down two or three times to fully wet out the
yarn, then turn the yarn over on the stick and repeat the dipping
processes, then allow to steep in the dye-liquor. This is done with
all the batch of yarn that is to be dyed at a time. When all the yarn
has been entered into the dye-bath, the first stickful is lifted out,
the yarn turned over and re-entered in the dye-liquor; this operation
is carried out with all the sticks of yarn until the wool has become
dyed of the required depth. In the case of long rectangular vats it is
customary for two men, one on each side of the vat, to turn the yarns,
each man taking charge of the yarn which is nearest to him.

Woven goods may be dyed in the tub or vat, the pieces being drawn in
and out by poles, but the results are not altogether satisfactory, (p. 042)
and it is preferable to use machines for dyeing piece goods.

Plain tubs or vats, such as those shown in figure 10, are used for
dyeing and otherwise treating goods in the cold, or at a lukewarm
heat, when the supply of hot water can be drawn from a separate
boiler. When, however, it is necessary to work at the boil, then the
vat must be fitted with a steam coil. This is best laid along the
bottom in a serpentine form. Above the pipe should be an open
lattice-work bottom, which, while it permits the free circulation of
boiling water in the vat, prevents the material being dyed from coming
in contact with the steam pipe. This is important if uniform shades
are to be dyed, for any excessive heating of any portion of the bath
leads to stains being produced on the material in that part of the
bath. Figure 11 shows a vat fitted with a steam pipe. That portion (p. 043)
of the steam pipe which passes down at the end of the vat is in a
small compartment boxed off from the main body of the vat, so that no
part of the material which is being dyed can come in contact with it.
A closed steam coil will, on the whole, give the best results, as then
no weakening of the dye-liquor can take place through dilution by the
condensation of the steam. Many dye-vats are, however, fitted with
perforated, or as they are called, open steam coils, in which case
there is, perhaps, better circulation of the liquor in the dye-vat,
but as some of the steam must condense there is a little dilution of
it.





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Previous: The Chlorination Of Wool



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