CENTRIFUGAL CLEANING MACHINES

149

they are unable to overcome the action of the centrifugal force, and climb
inwards over the lip. The water and lighter cellulose fibres pass this lip, and

are immediately flung out fur- \-----

ther into another ring, up • ~~

which they travel on account ! \ \

of the pressure behind them,
until they meet another pro-
jecting lip half-way up the
second ring. Here other im-
purities, less heavy than those
retained at the first lip, are
trapped, and the fibres and
water, passing over the lip, are
flung out still further into a
third ring of still greater diam-
eter. They proceed to climb
up the inner wall of the third
ring, where they meet yet
another projecting lip, and it is
in this ring where most of the
shive is caught. By the time the
fibres and water have reached
the end of this third ring they
are practically entirely free from
all foreign matter which is of
a higher specific gravity than
cellulose.

At this point it is possible to
remove lighter things, such as
rubber, cork, etc. This is done by
causing the nozzle of the skim-
mer to plough the inner surface
of the water and fibre just as it is
passing out of the final ring on
its way to the collecting trough
of the machine. This top skim-
ming contains, of course, valu-
able fibre, and it is at once led
into an auxiliary strainer, where the impurities are separated out of the stock;
which then goes back to the mixing-box chest or back-water supply service.

[VickcrysLtd.

FIG. 44>— VERTICAL ELEVATION AND PLAN OF THE
CENTKEFUGAL STOCK CLEANING MACHINE

This machine has three internal cylinders, and is very
accessible for cleaning