Main machines of plywood production: veneer drying

Whatever the method of veneer, eventually the veneer should be dried. The moisture content must be reduced to 5%-12%. The veneer moisture content is mostly more than 50% percent, so  the veneer drying step requires lots of energy. As we know, there are many machines used for veneer drying. We will introduce the four most commonly used veneer drying machines.

1. Veneer roller dryer machine. Comparing with other veneer dryers, the roller dryer behaves the best, the veneers go through the heated rollers, the rollers dry and press the veneers. The veneers dried in this way will get an excellent flatness; the thermal efficiency can reach 80%. But sometimes this dryer is not the first choice of customers, the cost of this dryer is too high, and it can only dry the veneers with a thickness more than 1.5mm, or the thin veneer will be shredded; apparently, it is not suitable for face veneer. And this machine will take larger places than other dryers.

2. Veneer belt dryer. This dryer is mainly used for face veneer drying, the belt transport the veneers into the drying cabin; then the veneers are dried by conviction. As the thickness of face veneer is very thin, the veneers can be well dried by convection. As the quantity of face veneer is not so much, many factories dry it together with core veneer in the same cabin, for example, the first and second layer are rollers for core veneer, the third layer is a belt for face veneer. And in many factories, they dry the face veneer with a simple iron cabin and iron wire conveyor.

3. Vertical type veneer dryer. This type of dryer is a new type of dryer. The heating cabin structure is the same as roller drying machine, but it uses vertical plate transmission instead of roller transmission. The veneer in the cabin is perpendicular to the bottom of the cabin. Compared with roller dryer, vertical type veneer dryer have the advantage of lower cost, large output, occupying less area.

4. Hot press type veneer dryer. The hot press veneer drying machine is just a hot press machine. It has the same structure to a hot press machine; its hot plate is specially designed so that the steam can get out fast. The veneer dried by this veneer dryer will have a supper flatness, and the machine will take a less area. But the cost of this machine is too high, and the drying capacity is not significant, only some factories who dry very thick veneer would like to prefer it. There is another innovation on hot press veneer dryer, some machine manufacturers use seamless steel pipe instead of the hot plate, and lower the pressure to reduce the weight of the machine, so the cost declines very much, and the facts prove that these innovations are very successful.