The working principle of the plywood dryer is mainly as follows:
Heat conduction drying
The board is preheated and dried under the clamp of the upper and lower two coils. The coils are heated by steam or heat conduction oil, and the heat is transferred to the board, so that the board is heated evenly, and the water evaporates during the benign physical process of wood contraction. After drying, the water content of the board is uniform, the wood is good color and the inside and outside are consistent, and no cracking, bending or deformation is generated. Suitable for drying poplar bark, pine bark, eucalyptus bark, etc.
Hot air drying
The centrifugal fan is used to send the hot air generated by the hot blast furnace into the upper and lower bellows, and then the hot air is blown to the upper and lower sides of the veneer by the nozzle of the bellows, so that the veneer is heated evenly and the effect of drying is achieved. When the board is working, the board enters the chassis through the feed port, and the chain drives the upper and lower rows of rollers to rotate. The board moves forward with the self-pressure of the upper rollers, and the hot air is blown to the board through the nozzle through the drying room to complete the drying.
Microwave drying
Using the thermal and biological effects of electromagnetic field, the water molecules in the plywood are polarized and oriented under the action of high frequency electromagnetic field, and the heat is generated by the friction between the molecules, so that the water evaporates quickly and the purpose of drying is achieved. At the same time, the microwave electric field can also change the permeability of the membrane cross section, so that the structure and function of bacteria and other microorganisms are disturbed, and play a bactericidal role.
High frequency drying
High frequency heating is used to achieve rapid temperature rise of the material, so that the water in the plywood quickly evaporates. High frequency drying has the advantages of fast heating speed, high drying efficiency, zero pollution emissions in the production process, and can make the drying quality of plywood better, ensure the bonding strength, and reduce the deformation rate.
