Abstract

The invention relates to an arrangement in drying sections intended for drying web material (2) which is arranged for movement through the drying section while supported by a plurality of air streams which impinge on the undersurface of the web and which extend parallel with, or substantially parallel with a plane allotted to the web, each of these air streams being given an exiting velocity and direction, via nozzle-like exit apertures (11, 11a) formed in a blow box (7), such as to maintain the web (2) in a suspended state above the blow box (7). Arranged in that end-part (8) of a blow box through which a flow of supply air (7a) is introduced thereinto is a means (20) operative in reducing and/or eliminating and/or over-compensating the influence of the velocity vector (7a') of the flow of supply air (7a) on the direction in which the air streams exit from the blow box through nozzle-like exit apertures (11,11a) formed therein and located adjacent the end-part (8) of the blow box. The interior of the blow box is divided into two chambers, a first chamber (71) intended for receiving the incoming flow of supply air (7a) and a second chamber (72) intended for receiving an air flow (7b,7c) separated from the incoming air flow, this separated air flow having a velocity vector which is considerably smaller than the velocity vector (7a') of the air flow entering the first chamber (71) and preferably having a direction opposite to the firstmentioned velocity vector.