104 MODERN PAPER-MAKING
To save time in furnishing the engine all the bales of pulp required should
be stacked close round the beater, or on a wooden stage at the edge, and before
the previous lot of stuff has been emptied the hoops should be removed and
taken away.
As soon as the stuff is let down the white water is turned on and the pulp
thrown in—so many bales of sulphite followed by the required amount of
mechanical The proportion is usually in the neighbourhood of 20 per cent
sulphite to 80 per cent mechanical.
As soon as the pulp is properly broken up and mixed, say in about i hour,
the valve is drawn and the stuff let down into the refiner chest. Here it is
diluted to a consistency suitable for pumping through the refining engine. It
is during its passage through the refiner that the beating (such as it is) and
clearing of the stuff are effected, and the beaterman manipulates the disc of the
refiner in the same way as the roll of the hollander is manipulated when beating
cotton and linen rags.
The consistency of the stuff as it passes through the refiner is important,
just as it was in the beater, and the more concentrated the stuff the more 'beating*
will it get, and vice versa.
It is usual to have two refiners coupled together, the stuff passing through
the first and then straight through into the second and into the machine chests.
The chief requirements for the satisfactory production of newsprint stock
is absolute uniformity hour by hour and day by day, so that the machine can
be kept going at full speed for very long periods without breaks. Consistency
regulators should always be fitted, in order to check and maintain the uniformity
of the stuff.
Once the machine has started up and got into its stride it is up to the beater-
man to keep his stuff absolutely regular and at a uniform degree of 'freeness',
so that just sufficient water will be carried to enable the sheet to be put together
and no more. Once the web reaches the suction boxes it must part readily
with its water so that it may be easily couched.
The beaterman must see that his assistants use care in furnishing so that
no pieces of wood or foreign matter get into the beater, as these things, when
broken up by the refiner, pass into the web in the form of small splinters and
shive, and cause breaks.
Properly beaten with suitable tackle, sulphite wood pulp can be made to
produce beautiful banks and bonds; and thin tissues, down to a substance of
5 Ib. Double Crown, may also be made, their strength, and toughness being
comparable with tissues made from rags.
The production of these thin papers necessitates long and careful beating
and proper tackle; blunt bronze bars or, better still, stone rolls give the best