BEATERS

75

be separated out before the actual beating begins. There is also much less
cutting or reduction of the length of individual fibres, as they are much shorter
than rag fibres to begin with.

The final clearing of knots and the reduction of the longer fibres to a uni-
form length are often performed by a refiner or perfecting engine. This is
invariably the case in the beating of newsprint and cheap printings, and in
most cases where the object is to get the beaten stock as Tree working' as
possible.

BEATERS

There are a great many different designs of beaters in general use, but these
may be divided, broadly, into two classes—viz. those which depend for the

[Messrs. Bertrams Ud.

FIG. 16.—PLAN OF SOENNES PATENT HOLLANDER BEATER, SHOWING THE WELL-DESIGNED SHAPE OF THE TROUGH,
WHICH ELIMINATES DEAD SPOTS AND AIDS CffiCULATEON
circulation of the stuff on the beater roll itself, and those which have a separate
circulating apparatus, either pump, screw or propeller.
The first named are the most universally employed, and in fact they are
entirely satisfactory for making all kinds of paper. The second group are
used for those fibres which are not liable to form strings, and they find favour
with some paper-makers who use a large proportion of esparto grass.
The first and foremost of all beaters is undoubtedly the hollander (Fig. 16),
which is, so far as is known, the first advance which was made on the 'stam-
pers*, and it was, no doubt, originally invented when the necessity arose for