DYEING MACHINERY AND DYEING MANIPULATIONS.
Cotton is dyed in a variety of forms: raw, loose cotton, partly
manufactured fibre in the form of slubbing or sliver, spun fibres or
yarns wound in cop or bobbin forms, 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.
[Illustration: FIG. 6.--Rectangular Dye-tank.] [Illustration: FIG.
7.--Round Dye-tub.]
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. Figs. 6 and 7 show respectively a rectangular vat and a
round tub much in use in dye-houses. These are 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 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 cotton
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.
The turning over one lot of yarn is technically called "one turn" and
the dyer often gives "three turns" or "four turns" as may be required.
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 and it is
preferable to use machines for dyeing piece goods.
[Illustration: FIG. 8.--Section of Dye-vat.]
Plain tubs or vats, such as those shown in Figs. 6 and 7, 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. Fig. 8 shows a vat
fitted with a steam pipe. That portion 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 the dye-liquor in the vat.
DYEING MACHINES.
Dye tubs and vats, such as those described above, have been largely
superseded by machines in which the handling, or working of the
materials being dyed is effected by mechanical means. There have been a
large number of dyeing machines invented, some of these have not been
found to be very practical, and so they have gone out of use. Space will
not admit of a detailed account of every kind of machine, but only of
those which are in constant use in dye-works.
=Dyeing Loose, or Raw Cotton.=--Few machines have been designed for this
purpose, and about the only successful one is:
=Delahunty's Dyeing Machine.=--This is illustrated in Fig. 9. It
consists of a drum made of lattice work, which can revolve inside an
outer wooden casing. The interior of the revolving drum is fitted with
hooks or fingers, whose action is to keep the material open. One segment
of the drum is made to open, so that the loose cotton or wool to be dyed
can be inserted. By suitable gearing the drum can be revolved; and the
dye-liquor, which is in the lower half of the wooden casing, penetrates
through the lattice work of the drum, and dyes the material contained in
it. The construction of the machine is well shown in the drawing, while
the mode of working is obvious from it and the description just given.
The machine is very successful, and well adapted for dyeing loose, or
raw wool and cotton. The material may be scoured, bleached, dyed, or
otherwise treated in this machine.
The Obermaier machine, presently to be described, may also be used for
dyeing loose cotton or wool.
DYEING, SLUBBING, SLIVER OR CARDED COTTON AND WOOL.
[Illustration: FIG. 9.--Delahunty's Dyeing Machine.]
[Illustration: FIG. 10.--Obermaier Dyeing Machine.]
It is found in practice that the dyeing of loose wool or cotton is not
altogether satisfactory--the impurities they naturally contain interfere
with the purity of the shade they will take. Then again the dyes and
mordants used in dyeing them are found to have some action on the wire
of the carding engine through which they are passed; at any rate a card
does not last as long when working dyed cotton or wool as when used on
undyed cotton or wool fibres. Yet for the production of certain fancy
yarns for weaving some special classes of fabrics, it is desirable to
dye the cotton or wool before it is spun into thread. The best plan is
undoubtedly to dye the fibre after it has been carded and partly spun
into what is known as slubbing or sliver. All the impurities have been
removed, the cotton fibres are laid, straight, and so it becomes much
easier to dye. On the other hand, as it is necessary to keep the sliver
or slubbing straight and level, no working about in the dye-liquors can
be allowed to take place, and so such must be dyed in specially
constructed machines, and one of the best of these is the Obermaier
dyeing machine which is illustrated in Fig. 10. The Obermaier apparatus
consists of a dye vat A. In this is placed a cage consisting of an inner
perforated metal cylinder C, and an outer perforated metal cylinder D,
between these two is placed the material to be dyed. C is in contact
with the suction end of a centrifugal pump P, the delivery end of which
discharges into the dye-vat A. The working of the machine is as follows:
The slubbing or sliver is placed in the space between C and D rather
tightly so that it will not move about. Then the inner cage is placed in
the dye-vat as shown. The vat is filled with the dye-liquor which can be
heated up by a steam pipe. The pump is set in motion, the dye liquor is
drawn from A to C, and, in so doing, passes through the material packed
in B and dyes it. The circulation of the liquor is carried on as long as
experience shows to be necessary. The dye-liquor is run off, hot water
is run in to wash the dyed material, and the pump is kept running for
some time to ensure thorough rinsing; then the water is run off, and by
keeping the pump running and air going through a certain amount of
drying can be effected. This machine works very well, and, with a little
experience, constant results can be obtained. The slubbing or sliver may
be scoured, bleached, rinsed, dyed, washed, soaped, or otherwise treated
without removing it from the machine, which is a most decided advantage.
[Illustration: FIG. 11.--Holliday's Yarn-dyeing Machine.]
=Holliday's Yarn-dyeing Machine.=--In Fig. 11 is given an illustration
of a machine for dyeing yarn in the hank form made by Messrs. Read
Holliday & Sons, of Huddersfield. The illustration gives a very good
idea of the machine. It consists of a wooden dye-vat which can be
heated by steam pipes in the usual way. Extending over the vat are a
number of reels or bobbins; these are best made of wood or enamelled
iron; these reels are in connection with suitable gearing so that they
can be revolved. There is also an arrangement by means of which the
reels can be lifted bodily in and out of the dye-vat for the purpose of
taking on and off, "doffing," the hanks of yarn for the reels. A reel
will hold about two pounds of yarn. The working of the machine is
simple. The vat is filled with the requisite dye-liquor. The reels,
which are lifted out of the vat, are then charged with the yarn, which
has been previously wetted out. They are then set in revolution and
dropped into the dye-vat and kept there until it is seen that the yarn
has acquired the desired shade. The reels are lifted out and the hanks
removed, when the machine is ready for another lot of yarn.
There are several makes of hank-dyeing machines of this type, and as a
rule they work very well. The only source of trouble is a slight
tendency for the yarn on one reel if hung loosely of becoming entangled
with the yarn on one of the other reels. This is to some extent obviated
by hanging in the bottom of the hank a roller which acts as a weight and
keeps the yarn stretched and so prevents it flying about.
To some makes of these machines a hank wringer is attached.
[Illustration: FIG. 12.--Klauder-Weldon Dyeing Machine.]
=Klauder-Weldon Hank-dyeing Machine.=--This is illustrated in Fig. 12,
which shows the latest form. This machine consists of a half-cylindrical
dye-vat built of wood. On a central axis is built two discs or rod
carriers which can revolve in the dye-vat, the revolution being given by
suitable gearing, which is shown at the side of the machine. On the
outer edge of the discs are clips for carrying rods, on which one end of
the hanks of yarn is hung, while the other end is placed on a similar
rod carried near the axle. The revolution of the discs carries the yarn
through the dye-liquor contained in the lower semi-cylindrical part of
the machine previously alluded to. At a certain point, every revolution
of the discs, the rods carrying the yarns are turned a little; this
causes the yarn to move on the rods, and this motion helps to bring
about greater evenness of dyeing. The most modern form of this machine
is provided with an arrangement by means of which the whole batch of
yarn can be lifted out of the dye-liquor. Arrangements are made by which
from time to time fresh quantities of dye can be added if required to
bring up the dyed yarn to any desired shade. This machine works well and
gives good results. Beyond the necessary labour in charging and
discharging, and a little attention from time to time, as the operation
proceeds, to see if the dyeing is coming up to shade, the machine
requires little attention.
Many other forms of hank-dyeing machines have been devised: there is
Corron's, in which an ordinary rectangular dye-vat is used. Round this
is a framework which carries a lifting and falling arrangement that
travels to and fro along the vat. The hanks of yarn are hung on rods of
a special construction designed to open them out in a manner as nearly
approaching handwork as is possible. The machine works in this way: the
lifting arrangement is at one end of the vat, the hanks are hung on the
rods and placed in the vat. Then the lifter is set in motion and moves
along the vat; as it does so it lifts up each rod full of yarn, turns it
over, opening out the yarn in so doing, then it drops it again in the
vat. When it has travelled to the end of the vat it returns, picking up
the rods of yarn in so doing, and this motion is kept up until the
dyeing is completed. This machine is very ingenious.
A type of machine which has been made by several makers consists of an
ordinary rectangular dye-vat surrounded with a framework carrying a
number of sets of endless chains, the links of which carry fingers. The
hanks of yarn are hung on rods at one end of which is a tooth wheel that
when in position fits into a rack on the side of the vat. The action of
the machine is this: the hanks are hung on the rods and placed at the
entrance end of the vat, by the moving of the chains it is carried along
the vat and at the same time revolves, thus turning over the yarn which
hangs in the dye-liquor; when it reaches the opposite end of the vat,
the rod full of yarn is lifted out, carried upwards and then towards the
other end of the vat when it is again dropped into the dye-vat to go
through the same cycle of movements which is continued until the yarn is
properly dyed.
COP DYEING.
In weaving fancy-coloured fabrics the ordinary mode is to dye the yarn
in the hank form, then those which have to be used for the weft are
wound into the cop form for placing in the shuttles. The cop form is
that in which the yarn leaves the spinning frame, and necessarily apart
from the dyeing there is labour involved in reeling it into hanks and
winding it back again into the cop form, not only so but there is
necessarily some waste made in these operations. Many attempts have been
made, with more or less success, to dye the yarn while in the cop form
and so save the cost of the hanking and copping above referred to as
well as the waste which occurs. Cops cannot be satisfactorily dyed by
simple immersion in a boiling dye-bath, the outside becomes dyed but the
central portions as often as not remain quite white, and there is a
distinct grading of colour or shade throughout the cop, the outer
portions being deeply dyed while the middle portion will only have a
medium shade and the central portions either not being dyed at all or
only faintly tinted, much depending on the firmness with which the cop
has been wound. A soft, loosely wound cop is much more thoroughly dyed
than a hard, tightly wound cop. This uneven dyeing of the cops is not
satisfactory, and must be avoided if cop dyeing is to be a success. Many
dyers have turned their attention to this question of dyeing yarn in the
cop form, and many machines have been devised for the purpose; some of
these have not been a success, but a few have been found to yield
satisfactory results and proved in practice very successful.
In all machines for dyeing cops one principle has been adopted--that of
drawing or forcing the dye-liquor through the cop.
[Illustration: FIG. 13.--Graemiger Cop-dyeing Machine.]
=Graemiger's Cop-dyeing Machine.=--This is shown in section in Figs. 13
and 14. Although simple in its work it is somewhat complex in its
construction and difficult to describe. The machine consists of a
dye-vat to hold the requisite dye-liquors. In the upper portions of this
is an iron casting formed with four chambers, the two lower ones of
which are immersed in the dye-liquor while the upper chambers are above
it. The sides of this casting are formed of metal plates which fit
tightly against the casting and form as nearly air-and water-tight
joints with it as it is possible to make. These metal plates are on a
spindle and can be rotated. They are perforated and made to carry
spindles, on which are placed the cops to be dyed. The two lower
chambers are in connection with a pump which draws the air from them and
so creates a vacuum inside the chambers. To fill this, liquor from the
dye-vat passes through the cops and into the chambers, and is in turn
drawn through the pump and returned to the dye-vat. In this way there is
a continual circulation of dye-liquors from the vat through the cops,
chambers and pump back to the vat again.
[Illustration: FIG. 14.--Graemiger Cop-dyeing Machine.]
The left upper chamber is practically a blank chamber. Those portions of
the cop carriers in contact with it are filled with cops, which are
placed on perforated spindles; the discs are given a quarter revolution
which brings the cops into the dye-liquor and in connection with the
left lower chamber and are dyed. At the same time the section of the cop
carriers now in contact with the left top chamber is filled with a new
lot of cops, another quarter of a revolution is given to the cop
carriers, which immerse the new lot of cops in the dye-liquor. The third
quarter of the cop plates is filled with cops. A third movement of the
cop plates now takes place; this brings the first lot of cops out of the
dye-liquor and in contact with the right upper chamber, where the
surplus liquor is drawn out of them and returned to the dye-vat. Another
revolution brings the cops back to their first position, they are now
removed and a new lot substituted. These proceedings go on
continuously. Although not quite free from defects the machine gives
very good results, the cops being very uniformly dyed through.
[Illustration: FIG. 15.--- Beaumont's Cop-dyeing Machine.]
=Beaumont's Cop-dyeing Machine.=--This is illustrated in Fig. 15. It
consists of a copper hemispherical dye-vessel, which is provided with a
tightly fitting lid, although this is not needed in all cases. The
bottom of the vessel is in communication with the suction end of a
centrifugal pump, while the delivery end of the pump is attached to the
upper end of the dye-vessel, the action of the pump being to secure a
constant circulation of dye-liquor from the bottom to the top of the
dye-vessel. Arrangements are provided by a peculiar and ingenious
contrivance fitted in one side of the dye-kettle for introducing steam
to heat the dye-liquor to any required degree. As in most forms of
cop-dyeing machines, the cops are placed on perforated metal spindles.
The cops and spindles are inserted in holes in a perforated metal plate,
and over them is placed a thin metal plate, technically called the
antifloater, whose object is to prevent the cops from becoming detached
from the plate. This plate, full of cops, is now placed in the
dye-vessel and rests upon a flange which is provided for that purpose.
When the cop plate is in position the dye-vessel is divided into two
chambers--a lower chamber and an upper one, in the latter being the
cops.
The pump draws liquor from the chamber under the cop plate and so
creates a vacuum, which during the working of the machines ranges from
10 to 20 inches in degree. To supply this vacuum, dye-liquor is drawn
from the upper chamber through the cops. The pump returns the liquor to
the dye-vessel. A very rapid circulation of dye-liquor takes place, from
25 to 50 gallons per minute passing through the cops and pump. From five
to ten minutes is sufficient to dye the cops. The machine is simple in
its construction and gives good results, the cops being completely dyed
through. One important consideration in cop dyeing is to be able to dye
successive batches of cops to exactly the same shade, and this is quite
possible with this machine.
=Young & Crippin's Cop-dyeing Machine.=--So far as simplicity of
construction is concerned this lies between the two preceding machines.
It consists of four parts with some accessory mechanism. There is first
a dye-liquor storage tank at the base of the apparatus in which the
liquor is kept stored and boiling (if necessary) ready for use, above
this and at the front end is the dye-chamber, this communicates at its
lower end by a pipe with the dye-liquor in the dye-vat. Then there is a
large vacuum chamber, in which by means of an injector a vacuum can be
formed, this directly communicates with a liquor-receiving chamber
which again in turn is in communication with the upper part of the
dye-chamber. The cops are placed on perforated spindles as usual, and
these on a perforated plate and are kept in place by a plate which is
screwed down on them. The charged cop plate is placed in the dye-chamber
on which a cover is placed and screwed down. By means of a lever the
injector is set at work, a vacuum created in the vacuum and receiving
chambers, the consequence being that dye-liquor is drawn from the vat
through the cops in the dye-chamber into the receiving chamber. When a
certain quantity of liquor has passed through, by a movement of a lever,
the vacuum is destroyed, and the dye-liquor runs back into the dye-vat;
these operations are repeated until from past experience of the working
of the machine it is thought sufficient has passed through to dye the
cops, when the dye-chamber is opened and the cops taken out. This
machine works very well.
=Mommer's Cop-dyeing Machine.=--This is in use in several continental
dye-works. The central portion of this machine is a rectangular
dye-chamber, which can be hermetically closed by hinged doors, the cops
are placed side by side on trays provided with perforated bottoms, the
trays being placed one on the top of the other in the dye-chamber. From
the top of the dye-chamber passes a pipe to a centrifugal pump, and a
similar pipe passes from the bottom of the chamber to the pump. A
separate vat contains the dye-liquor which is used. The pump forces the
dye-liquor through the cops which take up the dye. Arrangements are
provided by which the direction of the flow of the dye-liquor can be
changed. This machine gives fairly good results, not perhaps equal to
those with the machines previously described.
=Warp-dyeing Machines.=--Although many warps, especially for fancy
fabrics, are prepared from yarns dyed in the hank or cop form, yet it
is found advantageous when a warp is of one colour, a self-colour as it
is called, to form the warp from grey or white yarns and to dye it after
warping. If the warp were so wound as to be able to go into a Obermaier
dyeing machine, it would be possible to dye it in that machine, but
generally warps are dyed in the open form and are passed through a
dyeing vat, commonly called a warp-vat which is constructed as shown in
Fig. 16. These warp-dyeing machines generally consist of a long
rectangular wooden dye-vat, divided by two partitions into three
compartments, each provided with steam pipes to heat up its contents;
between the first and second and between the second and third
compartments is fitted a pair of squeezing rollers, while the third
compartment is fitted with a heavier pair of squeezing rollers. Motion
is given to these rollers by suitable gearing, and they serve to draw
the warp through the machine. Guide rollers are fitted in the
compartment, and the warp being taken round these, it passes several
times up and down and through the dye-liquors contained in the
compartments. These warp-dyeing machines may be made of sufficient width
to take one, two, three or more warps at one time as desired.
[Illustration: FIG. 16.--Warp-dyeing Machine.]
The three compartments of the machine may contain different liquids or
all the same liquid according as the nature of the shade to be dyed
demands. The passage is done slowly so as to give the warp time to
absorb the liquors and take up the dye. When all the length of warp has
been sent through, it is said to have been dyed "one end". Sometimes
this will be enough, but often it is not, and so the warp is sent
through again, given another end, and still again if the full shade has
not been attained.
After being dyed in this machine the warp is sent through another one
containing various wash liquors to finish the process.
[Illustration: FIG. 17.--Warp-dyeing Machine.]
Fig. 17 shows a warp-dyeing machine similar to, but a little more
elaborate in construction than, the vats just described.
=Piece-dyeing Machines.=--Wherever it is possible it is far more
preferable to dye textile fabrics in the form of woven pieces rather
than in the yarn from which they are woven. During the process of
weaving it is quite impossible to avoid the material getting dirty and
somewhat greasy, and the operations of scouring necessary to remove this
dirt and grease has an impairing action on the colour if dyed yarns
have been used in weaving it. This is avoided when the pieces are woven
first and dyed afterwards, and this can always be done when the cloths
are dyed in one colour only. Of course when the goods are fancy goods
containing several colours they have to be woven from dyed yarns.
[Illustration: FIG. 18.--Dye-jiggers.]
[Illustration: FIG. 19.--Dye-jigger.]
The most common form of machine in which pieces are dyed is The Jigger,
commonly called the jig. This is shown in Figs. 18 and 19. It consists
of a dye-vessel made sufficiently long to take the piece full
width--wide at the top and narrow at the bottom. At the top at each side
is placed a large winding roller on which the cloth is wound. At the
bottom of the jig is placed a guide roller round which passes the cloth.
In some makes of jigs (Fig. 19) there are two guide rollers at the
bottom and one at the top, as shown in the illustration, so that the
cloth passes several times through the dye-liquor. In working, the cloth
is first wound on one of the rollers, then threaded through the guide
rollers and attached to the other winding roller. When this is done
dye-liquor is run into the jig, the gearing set in motion, and the cloth
wound from the full on to the empty roller. With the object of keeping
the piece tight, a heavy press roller is arranged to bear on the cloth
on the full roller. When all the cloth has passed from one roller to the
other it is said to have been given "one end". The direction of motion
is now changed, and the cloth sent in the opposite direction through the
jig, and the piece has now received another "end". This alternation from
one roller to the other is continued as long as is deemed necessary,
much depending on the depth of colour which is being dyed--some pale
shades may only take two or three ends, deeper shades may take more.
When dyeing wool with acid colours which are all absorbed from the
dye-liquor, or the bath is exhausted, it is a good plan to run the
pieces several more ends so as to ensure thorough fixation of the dye on
the cloth.
It is not advisable in working these jigs to add the whole of the dye to
the liquor at the commencement, but only a part of it; then when one end
is given, another portion of the dye may be added; such portions being
always in the form of solution. Adding dyes in powder form inevitably
leads to the production of colour specks on the finished goods. The
reason for thus adding the dye-stuff in portions is that with some dyes
the affinity for the fibre is so great that if all were added at once it
would all be absorbed before the cloth had been given one end; and,
further, the cloth would be very deep at the front end, while it would
shade off to no colour at the other end. By adding the dye in portions
this difficulty is overcome and more level shades are obtained; it is
met with in all cases of jigger dyeing, but it is most common in dyeing
cotton or wool with basic dyes like magenta, auramine, methyl violet or
brilliant green, and in dyeing wool with acid dyes like acid green,
formyl violets, azo scarlet, or acid yellow.
Some attempts have been made to make jiggers automatic in their
reversing action, but they have not been successful; owing to the
greatly varying conditions of length of pieces, their thickness, etc.,
which have to be dyed, and it is next to impossible to make all
allowances for such varying conditions.
[Illustration: FIG. 20--Jig Wince.]
[Illustration: FIG. 21.--Cloth-dyeing Machine.]
=The Jig Wince or Wince Dye Beck.=--This dyeing machine is very largely
used, particularly in the dyeing of woollen cloths. It is made by many
makers, and varies somewhat in form accordingly. Figs. 20, 21 and 22,
show three forms by different makers. In any make the jig wince, or
wince dye beck, consists of a large rectangular, or, in some cases,
hemicylindrical dye-vat. Probably the best shape would be to have a vat
with one straight side at the front, and one curved side at the back. In
some a small guide roller is fitted at the bottom, under which the
pieces to be dyed pass. Steam pipes are provided for heating the
dye-liquors. The becks should be fitted with a false bottom made of
wood, perforated with holes, or of wooden lattice work, and below which
the steam pipes are placed; the object being to prevent the pieces from
coming in contact with the steam pipe, and so preventing the production
of stains. Above the dye-vat, and towards the back, is the wince, a
revolving skeleton wheel, which draws the pieces out of the dye-vat at
the front, and delivers them into it again at the back. The construction
of this wince is well shown in the drawings. The wince will take the
pieces full breadth, but often they are somewhat folded, and so several
pieces, four, five or six strings as they are called, can be dealt with
at one time. In this case a guide rail is provided in the front part of
the machine. In this rail are pegs which serve to keep the pieces of
cloth separate, and so prevent entanglements. The pieces are stitched
end to end so as to form an endless band. When running through the vat
they fall down in folds at the back part of the beck, and are drawn out
of the bottom and up in the front. Each part thus remains for some time
in the dye-liquor, during which it necessarily takes up the dye.
[Illustration: FIG. 22.--Dye Beck.]
In the jig and wince dyeing machines the pieces necessarily are for a
part of the time, longer in the case of the jigger than in that of the
wince, out of the dye-liquor and exposed to the air. In the case of
some dyes, indigo especially, this is not desirable, and yet it is
advisable to run the cloth open for some time in the liquor, so as to
get it thoroughly impregnated with the dye-liquor, or to become dyed.
This may be done on such a machine, as is shown in Fig. 24, page 79, but
having all the guide rollers below the liquor, so that at no time is the
piece out of the liquor, except, of course, when entering and leaving.
[Illustration: FIG. 23.--Holliday's Machine for Hawking Cloth.]
The so-called hawking machines have also this object in view, and Fig.
23 is an illustration of Holliday's hawking machine, made by Messrs.
Read Holliday & Sons, of Huddersfield. There is the dye-vat as usual; in
this is suspended the drawing mechanism, whose construction is well
shown in the drawing. This is a pair of rollers driven by suitable
gearing, between which the cloth passes, and by which it is drawn
through the machine. A small roller ensures the cloth properly leaving
the large rollers; then there is a lattice-work arrangement over which
the pieces are drawn. In actual work the whole of this arrangement is
below the surface of the dye-liquor in the vat. The piece to be dyed is
threaded through the machine, the ends stitched together. Then the
arrangement is lowered into the dye-vat and set into motion, whereby the
cloth is drawn continuously in the open form through the dye-liquor,
this being done as long as experience shows to be necessary. This
hawking machine will be found useful in dyeing indigo on cotton or wool,
or in dyeing cotton cloths with such dyes as Immedial blacks, Cross-dye
blacks, Amidazol blacks, Vidal blacks, where it is necessary to keep the
goods below the surface of the dye-liquor during the operation.
[Illustration: FIG. 24.--Continuous Dyeing Machine.]
Fig. 24 shows a form of cloth-dyeing machine much used in the cotton
trade. It consists of a number of compartments fitted with guide rollers
at top and bottom, and round which the cloth is threaded, so that it
passes up and down in the dye-liquor several times. Between each two
compartments is a pair of squeezing rollers to press out all surplus
liquors. All the compartments may be filled with the same dye-liquor, or
with different dye-liquors and developing liquors, as may be most
convenient and required for the work in hand. Such a machine is used in
dyeing logwood black, aniline black, and many of the direct colours,
etc.
From the direct colours a large number of light shades are dyed on to
cotton cloth by the process known as padding; this consists in passing
the cloth through a liquor containing the dye-stuff, usually a little
phosphate of soda is added, then between squeezing rollers, and finally
drying the cloth. For this process there is used what is called a
padding machine. This is shown in Figs. 25 and 26.
[Illustration: FIG. 25.--Padding Machine.]
[Illustration: FIG. 26.--Padding Machine.]
It consists essentially of a trough, which contains two or more guide
rollers, and in this is placed the padding liquor. Above the trough is
fitted squeezing rollers, sometimes two as in Fig. 25, or three as in
Fig. 26. Besides these, there are winding and beaming and other guide
rollers. Fig. 25 shows the simplest padding machine, where the cloth
passes once through the liquor and through the squeezing rollers. In
Fig. 26 the cloth passes several times through the liquor and twice
through the squeezing rollers, thus ensuring a more perfect impregnation
of the cloth with the dye-liquor, and therefore a more uniform dyeing of
the cloth.