The Dyeing of Cotton Fabrics Part 33

_Orange and Violet._--Dye the cotton with 2 lb. Diamine orange D C and the silk with 1 lb. Formyl violet S 4 B.

_Dark Blue and Olive._--Dye the cotton with 1-1/2 lb. Diamineral blue R and 1/2 lb. Diamine azo blue 2 R, and the silk with 1 lb. Naphthol yellow B and 1 lb. Orange G G.

_Green and Pink._--Dye the cotton with 1-1/2 lb. Diamine fast yellow A and 1/4 lb. Diamine sky blue, and the silk with 1 lb. Erythrosine B.

_Brown and Blue._--Dye the cotton with 3 lb. Mikado brown 2 B, and the silk with 1/2 lb. Pure blue.

It is quite possible to produce two coloured effects containing blue in one bath by using Alkali blue as a const.i.tuent with a direct dye which works only on to the cotton, the alkali blue going on to the silk, as, for example, in the following recipes:--

_Orange and Blue._--The dye-bath is made with 3 lb. Mikado orange 5 R O and 1-1/4 lb. Alkali blue 6 B. After the dyeing the goods are rinsed, then pa.s.sed through a bath of 1-1/2 lb. sulphuric acid in 10 gallons water, washed well and dried.

_Olive and Blue._--The dye-bath is made with 1-1/2 lb. Diamine fast yellow A, 2-1/2 lb. Diamine orange DC, 1/4 lb. Diamine sky blue, and 1 lb. Alkali blue 6 B, After dyeing rinse, then acidulate as above and wash well.

CHAPTER VII.

OPERATIONS FOLLOWING DYEING.

WAs.h.i.+NG, SOAPING, DRYING.

After loose cotton or wool, or cotton and woollen yarns, or piece goods of every description have been dyed, before they can be sent out for sale they have to pa.s.s through various operations of a purifying character. There are some operations through which cloths pa.s.s that have as their object the imparting of a certain appearance and texture to them, generally known as finis.h.i.+ng processes; of these it is not intended here to speak, but only of those which precede these, 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 manipulation 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 circ.u.mstances, in order to press 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, myrobolams, and the modern direct dyes which in 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 of goods.

Loose wool and loose cotton are somewhat difficult to deal with by squeezing or wringing, but the material may be pa.s.sed through a pair of squeezing rollers, such as are shown in Fig. 31, which will be more fully dealt with later on. The machine shown is made by Messrs Read Holliday & Sons.

[Ill.u.s.tration: FIG. 31.--Squeezing Rollers.]

_Yarns in Hanks._--In the hank-dyeing process the hanks are wrung by placing one end of the hank on a wringing horse placed over the dye-tub, a dye stick on 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 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 pa.s.sed 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 rollers is a familiar article, and quite common and in general use in dye houses.

_Piece Goods._--These are generally pa.s.sed open through a pair of squeezing rollers which are often attached to the dye-vat in which the pieces are dyed.

_Read Holliday's Squeezing Machine._--In Fig. 31 is shown a squeezing machine very largely employed for squeezing all kinds of piece goods and cotton warps after dyeing or was.h.i.+ng. 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 waggons for conveyance to other machines. This machine is effective.

Another plan on which roller, or rather in this case disc, squeezing machines is made, is to make the bottom roller with a square groove in the centre, into this fits a disc, the cloth pa.s.sing 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.

=Was.h.i.+ng.=--One of the most important operations following that of dyeing is the was.h.i.+ng with water to free the goods, whether cotton or woollen, from all traces of loose dye, acids, mordanting materials, etc., which it is not desirable should be left in, as they might interfere with the subsequent finis.h.i.+ng operations. For this purpose a plentiful supply of good clean water is required; this should be as soft as possible, free from any suspended matter which might settle upon the dyed goods, and stain or speck them.

Was.h.i.+ng may be done by hand, as it frequently was in olden days, by simply immersing the dyed fabrics in a tub of water, shaking, then wringing out, again placing in fresh water to finish off. Or if the dye-works were on the banks of a running stream of clean water the dyed goods were simply hung in the stream to be washed in a very effectual manner.

In these days it is best to resort to was.h.i.+ng machines adapted to deal with the various kinds of fibrous materials and fabrics in which they can be subjected to a current of water.

[Ill.u.s.tration: FIG. 32.--Yarn-was.h.i.+ng Machine.]

_Loose Wool and Cotton._--If this has been dyed by hand then the was.h.i.+ng may also be done in the same way by hand in a plain vat. If the dyeing has been done on a machine, then the was.h.i.+ng can be done on the same machine.

_Yarns._--Yarn in the cop form is best washed in the machine in which it is dyed.

_Yarns in Hanks._--A very common form of was.h.i.+ng machine is shown in Fig. 32. As will be seen it consists of a wooden vat, over which are arranged a series of revolving reels on which the hanks are hung. The hanks are kept in motion through the water, and so every part of the yarn is thoroughly washed. Guides keep the hanks of yarn separate and prevent any entanglement one with another. A pipe delivers constantly a current of clean water, while another pipe carries away the used water.

Motion is given to the reels in this case by a donkey engine attached to the machine, but it may also be driven by a belt from the main driving shaft of the works. This machine is very effective.

[Ill.u.s.tration: FIG. 33.--Dye-house Was.h.i.+ng Machine.]

_Piece Goods._--Piece goods are mostly washed in machines, of which two broad types may be recognised; first, those where the pieces are dealt with in the form of ropes in a twisted form, and, second, those where the pieces are washed open. There are some machines in which the cloths may be treated either in the open or rope form as may be thought most desirable.

[Ill.u.s.tration: FIG. 34.--Cloth-was.h.i.+ng Machine.]

Fig. 33 represents a fairly well-known machine, made by Messrs. Mather & Platt, in which the pieces are treated in a rope-like form. It consists of a trough in which a constant current of water is maintained. At one end of this trough is a square beating roller, at the other a wooden lattice roller. Above the square beater, and out of the trough, are a pair of rollers whose purpose is to draw the cloth through the machine and also partly to act as squeezing rollers. As will be seen the cloth is threaded in rope form spirally round the rollers, pa.s.sing in at one end and out at the other, pegs in a guide rail serving to keep the various portions separate. The square beater in its revolutions has a beating action on the cloth tending to more effectual was.h.i.+ng. The lattice roller is simply a guide roller.

Fig. 34 shows a was.h.i.+ng machine very largely used in the wool-dyeing trade. The princ.i.p.al portion of this machine is of wood.

The internal parts consist of a large wooden bowl, or oftener, as in the machine under notice, of a pair of wooden bowls which are pressed together by springs with some small degree of force. Between these bowls the cloth is placed, more or less loosely twisted up in a rope form, and the machines are made to take four, six or eight pieces, or lengths of pieces, at one time, the ends of the pieces being st.i.tched together. A pipe running along the front of the machine conveys a constant current of clean water which is caused to impinge in the form of jets on the pieces of cloth as they run through the machine, while an overflow carries away the used water. The goods are run in this machine until they are considered to be sufficiently washed, which may take half to one and a half hours.

In Fig. 35 is shown a machine designed to wash pieces in the broad or open state. The machine contains a large number of guide rollers, built more or less open, round which the pieces are guided--the ends of the pieces being st.i.tched together. Pipes carrying water are so arranged that jets of clean water impinge on and thoroughly wash the cloth as it pa.s.ses through--the construction of the guide rollers facilitating the efficient was.h.i.+ng of the goods.

[Ill.u.s.tration: FIG. 35.--Cloth-was.h.i.+ng Machine.]

=Soaping.=--- Sometimes yarns or cloths have to be pa.s.sed through a soap bath after being dyed in order to brighten up the colours or develop them in some way. In the case of yarns this can be done on the reel was.h.i.+ng machine such as is shown in Fig. 32. In the case of piece goods, a continuous machine, in which the was.h.i.+ng, soaping, etc., can be carried on simultaneously, is often employed. Such a machine is shown in Fig. 36. It consists of a number of compartments fitted with guide rollers so that the cloth pa.s.ses up and down several times through the liquors in the compartments. Between one compartment and another is placed a pair of squeezing rollers. The cloth is threaded in a continuous manner, well shown in the drawing, through the machine. In one compartment it is treated with water, in another soap liquor, in another water, and so on; and these machines may be made with two, three or more compartments as may be necessary for the particular work in hand. As seen in the drawing, the cloth pa.s.ses in at one end and out at the other finished. It is usually arranged that a continuous current of the various liquors used flows through the various compartments, thus ensuring the most perfect treatment of the cloths.

[Ill.u.s.tration: FIG. 36.--Was.h.i.+ng and Soaping Vats.]

=Steaming.=--Sometimes it becomes necessary to subject dyed goods to a process of steaming, as, for instance, with steam aniline blacks, khaki shades, alizarine reds, etc., for the purpose of more fully developing and fixing the dye upon the fibre. In the case of yarns, this operation is carried out in the steaming cottage, one form of which is shown in Fig. 37. It consists of a horizontal cylindrical iron vessel like a steam boiler, one end is entirely closed, while the other is made to open and be closed tightly and hermetically. The cottage is fitted with the necessary steam inlet and outlet pipes, drain pipes for condensed water, pressure gauges. The yarn to be steamed is hung on rods placed on a skeleton frame waggon on wheels which can be run in and out of the steaming cottage as is required. The drawing shows well the various important parts of the machine. In the case of piece goods these also can be hung from rods in folds on such a waggon, but it is much more customary to employ a continuous steaming chamber, very similar to the ageing and oxidising machine shown in Fig. 38, and also used in the dyeing of aniline black.

[Ill.u.s.tration: FIG. 37.--Steaming Cottage.]

[Ill.u.s.tration: FIG. 38.--Steaming and Ageing Chamber.]

=Drying.=--Following on the was.h.i.+ng comes the final operation of the dyeing process, that of drying the dyed and washed goods. Textile fabrics of all kinds after they have pa.s.sed through dye-baths, was.h.i.+ng machines, etc., contain a large amount of water, often exceeding in weight that of the fibre itself, and to take the goods direct from the preceding operations to the drying plant means that a considerable amount of fuel must be expended to drive off this large amount of water.

It is therefore very desirable that the goods be freed from as much of this water as possible before they are sent into any drying chambers, and this may be done in three ways, by wringing, squeezing and hydro-extracting. The first two methods have already been described (p.

239, etc.) and need not again be alluded to; the last needs some account.

[Ill.u.s.tration: FIG. 39.--Hydro-extractor.]

Hydro-extractors are a most efficient means for extracting water out of textile fabrics. They are made in a variety of forms by several makers.

Essentially they consist of a cylindrical vessel, or basket, as it is called, with perforated sides so constructed that it can be revolved at a high speed. This vessel is enclosed in an outer cage. The goods are placed in the basket, as it is termed, and then this is caused to revolve at high speed, when centrifugal action comes into play, and the water contained in the goods finds its way to the outside of the basket through the perforations, and so away from the goods. Hydro-extractors are made in a variety of sizes and forms--in some the driving gear is above, in others below the basket; in some the driving is done by belt-gearing, in others a steam engine is directly connected with the basket. Figs. 39 and 40 show two forms which are much in use in the textile industry. They are very efficient, and extract water from textile goods more completely than any other means, as will be obvious from a study of the table below.

[Ill.u.s.tration: FIG. 40.--Hydro-extractor.]