A sizing device that is usually part of the
papermaking machine. It is essentially a vat (tub)
which contains the size, and a set of vertically
oriented rolls. the lower part of the unit being
immersed in the size. The paper is sized as it
travels through the papermaking machine. Sometimes
a set of horizontally oriented rolls is used and
the size solution is then pumped into the "valley"
created on both sides of the paper. The tub-size
press is designed for relatively heavy
applications of size to paper. See also: SURFACE-SIZE PRESS .