Sequential unloading results in more consistent grading and reduces dryer outfeed plug-ups and veneer sheet damage, especially at higher veneer processing speeds. Sheets are removed from the dryer as soon as they are detected, thus optimizing the system to its fullest, which is critical when operating at the highest possible dryer speeds.
Inch Rolls and Veneer Detection:
The infeed of the sequential unloader features two pairs of pinch rolls at each of the four vertical decks. The pinch rolls rotate faster than the dryer rolls, thus pulling the sheets from the dryer and creating a gap between the veneer sheet loads.
Typically, the veneer inside the dryer can have anywhere from a 6” gap between sheet ends or they can be butted up or “overlapped” by one inch or more.
If the unloader did not “pull” a gap between sheets, the multiple decks of the dryer would not merge evenly to one level, as we would sense a continuous flow of veneer on each deck and a bottleneck would occur.