The Dyeing of Woollen Fabrics | Page 8

work the wool about too much, otherwise (p. 019) felting might ensue and this must be avoided. The felting of the wool is one of the troubles of the wool-scourer and is often difficult to avoid, it is mostly brought about by excessive working of the wool during the process, and by the use of too high a temperature in the scouring bath. The remedies are obvious to the practical man, as little handling of the wool as possible, and at as low a temperature as possible. Still it is necessary to see that the scouring liquor penetrates to every part of the wool which is being treated.
To ensure this, care must be taken not to scour too much at one time, so that the wool is loosely placed in the scouring tub, if placed loose in the latter, the workmen can by means of forks work it to and fro while in process of treatment. After the wool has been through these scouring liquors it is thrown on a scray to drain, and is next placed in cisterns which have perforated false bottoms. In these cisterns it is washed with cold water two or three times, the water being run off from the wool between each washing; it is then spread out in a room to dry. As a rule, a man can wash from 500?lb. to 600?lb. of wool in a day by this method. Another plan which is sometimes adopted so as to avoid handling the wool as much as possible, and thus prevent felting, is to place the wool in cages having perforated sides which will hold about 1?cwt. of wool. They are lowered by means of cranes into the washing liquors, and the wool in them is then worked for a quarter of an hour, when the cages and their contents are lifted out and the surplus liquor allowed to drain off. They are then lowered into the next bath, treated or worked in this, again lifted out and dropped into the wash waters.
There is by this plan a saving of handling, and more wool can be got through in the same time, but it requires two men to work it. These hand processes are only in use in small works, having been (p. 020) replaced in all large works by mechanical methods described below.
#Machine Scouring.#--Wool-scouring machinery has been brought to a high state of perfection by the successive efforts of many inventors, and by their means wool washing has been much simplified and improved. Wool-washing machinery is made by several firms, among whom may be mentioned Messrs. J. & W. McNaught, and John Petrie, Junior, Limited, both of Rochdale.
[Illustration: Fig. 6.--Wool-washing Machine.]
Fig. 6 shows one form of wool-washing machine. It consists of a long trough which contains the scouring liquor. In this machine the wool enters at the left-hand end, and is seized by a fork or rake and carried forward by it a short distance, then another rake seizes it and carries it further forward to another rake, and this to the last rake of the machine, which draws it out of the machine to a pair of squeezing rollers which press out the surplus liquor, and from these rollers the scoured wool passes to a travelling band for delivery from the machine. Sometimes the wool is not entered into the trough direct, but is put on a travelling apron which opens it and delivers it in a more open form into the trough. The movement of the forks causes some degree of agitation in the scouring liquor which facilitates the penetration of the liquor through the wool, and thus brings about a better scouring.
After the wool has passed through the machine it is taken and run once more through the machine. Some scourers use the same liquor, but it is better to use fresh liquors, after which it is washed in the same machine with water two or three times. With a single machine there is some time and labour lost in transferring the wool from one end to the other between the separate treatments, and in large works where a great deal of wool is scoured it is usual to place three or four of these machines end to end.
The first is filled with strong scouring liquor, the second with (p. 022) a weaker liquor, while the third and fourth contains wash waters, and the wool is gradually passed by the action of the machine through the series without requiring any manual aid. Between each machine it is passed through squeezing rollers as before, and finally emerges thoroughly scoured. A good plan of working in connection with such a series of machines is to have four as above, two washing machines and two soaping machines, the soap liquor is run through