Veneer dryer is a kind of plywood machine, is a continuous veneer drying equipment, is also an indispensable equipment for plywood manufacturer At present, the most widely used veneer dryers are mainly mesh belt type veneer dryer and roller type veneer dryer. Because the circulation of hot air is different, mesh belt veneer dryer and roller veneer dryer can be divided into many types. Although there are many types of dryers, their structure has many common features. Each dryer includes two parts: drying area and cooling area.
The drying area mainly heats the veneer and evaporates the moisture of the veneer through the circulation of hot air. The drying area is composed of multiple sub-chambers according to the output requirements, and the structure of each sub-chamber is the same. The longer the drying zone, the faster the speed of conveying the veneer, and the higher the output.
The function of the cooling zone is to allow the veneer to be cooled by ventilation during the transmission process that keeps the pressure. It can eliminate the stress in the board and make the board more flat. On the other hand, part of the water is evaporated using the temperature gradient of the veneer surface and the core layer. The cooling zone is generally composed of 1-2 sub-chambers.
There are generally two types of board transmission methods: one is to use upper and lower mesh bags for transmission. The lower layer of mesh bags is mainly used for support and transmission. The upper layer of mesh bags is used to give the appropriate compression force to the board to prevent The veneer is deformed during the drying process; the other is composed of a pair of upper and lower rollers, which rely on the rotation and friction of the roller to drive the veneer forward. The distance between the front and rear rollers should not be too small, so this This transmission method is suitable for single boards with a thickness of 0.5mm or more. The conveying and pressing force of the roller is relatively large, so the flatness of the veneer after drying is better than that of the mesh bag.
Most of the veneer dryers currently used use steam as a heat source. It is also possible to heat the cold air by burning processing residues such as gas, fuel oil, and wood. There are generally two types of hot air circulation, horizontal and vertical. The same veneer dryer uses different blowing methods, and the drying effect will be different.
The number of layers of the veneer dryer is 2-5 layers. The general air-jet mesh belt veneer dryer is usually 2 or 3 layers, because the wet board is dried and then cut, and the dryer needs to be equipped with a shear at the board end. Other roller veneer dryer and mesh belt veneer dryer shear first and then dry the veneer. In order to improve the production capacity of the veneer dryer, 5 more layers are used.
There are two longitudinal and transverse directions of the veneer dryer's plate feeding direction. If the direction of entering the board is the same as the fiber direction of the veneer, it is entering the board longitudinally. Generally, the mesh belt veneer dryer and the roller veneer dryer adopt the longitudinal feeding method. If the direction of the board feeding is perpendicular to the fiber direction of the veneer, it is called transverse board feeding, and the air-jet mesh belt veneer dryer adopts the method of transverse board feeding.
Longitudinal feeding must cut the veneer after rotation cutting into a single veneer before drying. Lateral feeding can dry the whole veneer first and then cut it. At present, jet-type mesh belt veneer dryer are widely used at home and abroad. The high-temperature and high-speed hot air flow is sprayed vertically from both sides of the veneer onto the veneer, which greatly speeds up the drying of the veneer and creates a continuous drying of the veneer. condition.
The above is an overview of the veneer dryer, I hope it will help you.