| 摘要 |
The invention relates to a plant for drying a material web. Such plant includes a plurality of upper (3) and lower blow boxes arranged substantially mutually parallel and at right angles to the travelling direction of the web. The lower boxes are intended to support the web and are provided in their surfaces facing towards the web with orifices for blowing air in directions substantially parallel to the plane of the web. The air ejection velocity is thereby sufficient to maintain the web in a specified floating position above said boxes. The upper blow boxes (3) are situated on the other side of the material web and have orifices for blowing air substantially perpendicularly to the plane of the web. According to the invention, the distance (H) between the blowing orifices of the upper blow boxes and the web is variable. It is furthermore adjustable so that the relative energy requirement for the upper blow boxes may be brought closely into the region of the value 1. The variable distance (H) may be provided, in accordance with one embodiment of the invention, by the upper blow boxes (3) being at one end ( 6) pivotably mounted in a wall (7) of a compressed air chamber, while their other ends (8) are movable in height for adjusting the distance (H) to the underlying, fixed web-positioning blow box (4). |
