Louvered steam box for controlling moisture profile of a fibrous web

摘要

A steam box or hood for controlling the moisture profile of a fibrous web such as paper during forming and pressing is described. The steam hood includes a plenum filled with nonturbulent, substantially atmospheric pressure steam which delivers the steam into a series of side- by-side compartments which extend across the width of and adjacent to the web. Each compartment includes a damper, the position of which is individually controllable through a rod adjustment from the operating side of the machine. The position of the damper determines the amount of steam applied to the web from a compartment and hence the moisture content of the web adjacent to the particular compartment being adjusted. Each compartment is adjusted to achieve a desired uniform moisture content across the width of the web.