Operations Following Dyeing Washing Soaping Drying
After loose wool, or woollen yarns or piece goods of every description
have been dyed, before they can be sent out for sale they have to pass
through various operations of a purifying character. There are some
operations through which cloths pass that have as their object the
imparting of a certain appearance and texture to them, these are
generally known as finishing processes, of these it is not intended
here to spea
, but only of those which precede them but follow on the
dyeing operations.
These processes are usually of a very simple character, and common to
most colours which are dyed, and here will be noticed the appliances
and manipulations necessary in the carrying out of these operations.
#Squeezing or Wringing.#--It is advisable when the goods are taken out
of the dye-bath to squeeze or wring them according to circumstances in
order to express out all surplus dye-liquor, which can be returned to
the dye-bath if needful to be used again. This is an economical
proceeding in many cases, especially in working with many of the old
tannin materials, like sumac, divi-divi, myrobalans, and the modern
direct dyes, which during the dyeing operations are not completely
extracted out of the bath, or in other words the dye-bath is not
exhausted of colouring matter, and therefore it can be used again for
another lot of goods simply by adding fresh material to make up for
that absorbed by the first lot.
Loose wool and loose cotton are somewhat difficult to deal with by (p. 198)
squeezing or wringing, but the material may be passed through a pair
of squeezing rollers such as are shown in figure 24, which will be
more fully dealt with later on.
#Yarns in Hanks.#--In the hand-dyeing process of hank-dyeing the hanks
are wrung by placing one end of the hank on a wringing-horse placed
over the dye-tub, and a dye-stick in the other end of the hank, giving
two or three sharp pulls to straighten out the yarn and then twisting
the stick round; the twisting of the yarns puts some pressure on the
fibres thoroughly and uniformly squeezing out the surplus liquor from
the yarn.
#Hank-Wringing Machines.#--Several forms of hank-wringing machines have
been devised. One machine consists of a pair of discs fitted on an
axle, these discs carry strong hooks on which the hanks are placed.
The operator places a hank on a pair of the hooks. The discs revolve
and carry round the hank, during the revolution the hank is twisted
and the surplus liquor wrung out, when the revolution of the discs
carries the hank to the spot where it entered the machine, the hooks
fly back to their original position, the hank unwinds, it is then
removed and a new hank put in its place, and so the machine works on,
hanks being put on and taken off as required. The capacity of such a
machine is great and the efficiency of its working good.
Mr. S. Spencer, of Whitefield, makes a hank-wringing machine which
consists of a pair of hooks placed over a vat. One of the hooks is
fixed, the other is made to rotate. A hank hung between the hooks is
naturally twisted and all the surplus liquor wrung out, the liquor
falling into the vat.
#Roller Squeezing Machines for Yarn.#--Hanks may be passed through a
pair of indiarubber squeezing rollers which may be so arranged that
they can be fixed as required on the dye-bath. Such a pair of (p. 199)
rollers is a familiar article and quite of common and general use in
dye-houses.
#Piece Goods.#--These are generally passed open through a pair of
squeezing rollers, which are often attached to the dye-vat in which
the pieces are dyed.
[Illustration: Fig. 24.--Read Holliday's Yarn-squeezing Machine.]
#Read Holiday's Squeezing Machine.#--In figure 24 is shown a squeezing
machine very largely employed for squeezing all kinds of piece goods
after dyeing or washing. It consists of a pair of heavy rollers on
which, by means of the screws shown at the top, a very considerable
pressure can be brought to bear. The piece is run through the eye
shown on the left, by which it is made into a rope form, then over
the guiding rollers and between the squeezing rollers and into (p. 200)
waggons for conveyance to other machines. This machine is effective.
Another plan on which roller, or rather in this case disc, squeezing
machines are made is to make the bottom roller with a square groove in
the centre, into this fits a disc, the cloth passing between them. The
top disc can, by suitable screws, be made to press upon the cloth in
the groove and thus squeeze the water out of it.