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.
One of the most important operations following that of dyeing is the washing 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 finishing 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.
Washing 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 washing machines adapted to deal with the various kinds of fibrous materials and fabrics, in which they can be subjected to a current of water.
#Loose Wool.#--If this has been dyed by hand then the washing 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 washing can be done on the same machine.
[Illustration: Fig. 25.--Hank-washing Machine.]
#Yarn in Hanks.#--A very common form of washing machine is shown (p. 202) in figure 25. 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.