250

MODERN PAPEK-MAKING

The presses at first are small and fairly light, and are placed in rotation,
in steps, leading down to the main heavy press roll. These small presses are
generally called 'baby' presses (Fig. 105), and they serve to squeeze and in-
corporate the four webs of paper together gradually before the main pressure
is applied by the heavy press, which is usually of granite.

The 'baby' presses are of wood or metal, and are usually from five to seven
in number; the web passes straight through them and is not reversed. At the

[HJ. emd A. Cwlthurst, Ltd.
FIG. 106.—A BATTERY OF CHESTS FOR SUPPLYING STUFF TO THE VATS OF A MUITEPI&-VAT BOARD MACHINE

' presses another felt comes into action and is in contact with the upper
side of the paper during its passage through them.

Hie wet fell carries the web right to the main press roll; this wet felt passes
a fek washiag-tank and squeezing rolls before teturning to the vats
£ a foftfeer web of paper.

c iMJotky of papers made on board machines are either 'duplex7 or
* as a rale, a fece of pure sulphite and a back of a