extracting 77.8 75.5 82.3 86.0

In the practical working of hydro-extractors it is of the utmost
importance that the goods be carefully and regularly laid in the
basket--not too much in one part and too little in another. Any
unevenness in this respect at the speed at which they are driven lays
such a strain on the bearings as to seriously endanger the safety of the
machine.

After being wrung, squeezed or hydro-extracted the goods are ready to be
dried. In the case of yarns, this may be done in rooms heated by steam
pipes placed on the floor, the hanks being hung on rods suspended from
racks arranged for the purpose.

[Illustration: FIG. 41.--Automatic Yarn-dryer.]

Where large quantities of yarn have to be dried, it is most economical
to employ a yarn-drying machine, and one form of such is shown in Fig.
41. The appearance of the machine is that of one long room from the
outside; internally it is divided into compartments, each of which is
heated up by suitably arranged steam pipes, but the degree of heating in
each compartment varies--at the entrance end it is high, at the exit end
lower. The yarn is fed in at one end, being hung on rods, and by
suitable gearing it is carried directly through the various chambers or
sections, and in its passage the heat to which it is subjected drives
off the water it contains. The yarn requires no attention from the time
it passes in wet at the one end of the machine and comes out dry at the
other end. The amount of labour required is slight, only that
represented by filling the sticks with wet yarn and emptying them of the
dried yarn. The machine works regularly and well.

[Illustration: FIG. 42.--Truck Yarn-dryer.]

The drying is accomplished by circulating heated air through the yarns,
this heating being effected by steam coils, fresh air continually enters
the chambers, while water-saturated air is as continually being taken
out at the top of the chamber. One of the great secrets in all drying
operations is to have a constant current of fresh hot air playing on the
goods to be dried; this absorbs the moisture they contain, and the
water-charged air thus produced must be taken away as quickly as
possible.

[Illustration: FIG 43.--Drying Cylinders.]

Fig. 42 shows what is called a truck yarn-dryer, which consists of a
chamber heated with steam pipes and fitted with an exhausting fan to
draw out the air and water vapour which is produced. The ya