BEATING.
The process is called beating because it has displaced the original method of maceration by mallets and later by the machine described in [Chapter I] as a “stamper.”
The ultimate characteristics of the paper are dependent upon the handling of the beater roll and the character of the knives. For example, a blotting-paper is made by a quick beating with sharp knives. This cuts the fibers clean and short and leaves them in a most absorptive condition. The very same fibers, treated with dull knives and slowly beaten, would have an entirely different character. Their ends would be teased out and ragged, and in the process of manufacture they would part very slowly from the water absorbed. The paper produced would have the characteristics of a writing-paper, hard and strong. This instance will afford some idea of the wide variation in results which may be brought about by varying the treatment in the beaters. So important is this step in manufacturing that it has been said with a good deal of truth that “the paper is made in the beaters.”
After the process has been continued a sufficient length of time, the stuff is emptied into a chest called the “Jordan chest,” because it acts as a reservoir for another type of refining engine known as the “Jordan.” This engine is conical in shape and the inside is lined with knives. A cone-shaped plug, also shod with knives, fits into this shell, and by the turn of a screw may either be moved in or out, thus varying the space between the two sets of knives. By this adjustment the refining of the pulp which flows through the engine is regulated.
The stock passes through one or more of these “Jordans” into the machine chest. Thence it is pumped to a level higher than the machine, and flows through “sand settlers” to a screen. The “sand settler” is a long, open trough containing a series of baffle boards which collect any sediment, preventing it from getting into the paper.
Screens are of various types, the main feature consisting of bronze plates pierced with fine slots through which the fibers are forced. The object is to give uniformity to the stock which reaches the machine, and to exclude any knots of stock, strings or foreign substances.
The width of the slots is varied to suit different stocks—some slots being as fine as 10/1000 of an inch.
We have now described the process of paper-making up to the point where the stuff is formed into paper, and must pause for a description of the paper-machine itself.