264 MODERN PAPER-MAKING

Another system, known as the Liebeck fibrator, is an attractive alternative
to the generally adopted breaker method. In this arrangement, bales are packed
together in line on a conveyor, but instead of being forced by the moving
conveyor direct against a disintegrating roll, the pulp falls, bale by bale, into
a large oblong concrete breaker chest capable of holding 5000 Ib. of stock
at 3 per cent consistency. The chest is fitted with a horizontal shaft, on which
are fitted large disintegrating propellers, and as the bales are fed in, they fall
some 10 or 12 feet either on to the shaft itself, or on to stationary horizontal
concrete baffles which protect the propellers. This heavy fall helps to split
the bales into laps, and then the propellers thrashing round are very effective
in breaking the laps down to slnsh form. These breakers require about 30
minutes, including loading time, to treat the stock. f'

Both the Sturtevant whole bale pulper and the Liebeck system are able to
handle pulp that is difficult to disintegrate rather more satisfactorily than con-
ventional breakers. Thus, the Liebeck breaker is able to handle frozen pulp
without any prior hacking and man-handling of the bales to separate the laps.
The Sturtevant pulper has been employed successfully to break up dry Kraft,
a task which is very difficult in an ordinary breaker. Both these methods of
pulping, however, suffer from the disadvantage that labour is still required to
load the pulp on to the conveyors, and to remove the baling wires. Perhaps
for this, among other reasons, these newer methods have not displaced the
breaker system to any appreciable extent for newsprint.

An arrangement for the breaking and preliminary treatment of pulp that
has operated satisfactorily in several news mills in this country has been to have
for each machine, making about 150 tons of paper per 24 hours, a battery of
three i-ton breakers for handling the groundwood, one i-ton sulphite breaker
and two i-ton sulphite beaters. The beaters, unlike the breakers, are fitted
with bed-plates, but they do very little real beating, and chiefly help to dis-
integrate die pulp further. The groundwood breakers operate independently
and discharge the stock into a common breaker chest. The sulphite breaker
may be arranged to discharge the stock direct to a pump which transfers the
stock to one of the two beaters, where the pulping treatment is continued for
about an hour. The sulphite beaters then discharge the stock into a sulphite
stock storage chest.

and sulphite pulp are thus, in modern practice, broken and
separately in die early stages. The breakers, in eadi case, are
tack-water obtaked by gravity from the back-water storage tank, and
^whoi'tbfc brokecHup ,$tod; is let down into the storage chests, additional badb-
"iKKtac is added to wash down die rather thick 5 to 6 per cent stock. This
"washing dilutes tfae stock to about 3 per cent, and in order to keep the