Significance and Function of Wood Drying
Wood has low density and high strength (high quality coefficient), acid and alkali corrosion resistance, good insulation, easy cutting, beautiful texture and color. In the construction, machinery, vehicles, ships, textiles, agricultural tools, furniture, musical instruments, aviation and other parts of the national economy need to use a large amount of wood. However, the quality of products made from undried wood can not be guaranteed, so the wood must be dried.
After drying, the following effects can be achieved:
(1) Improve the stability of wood and wood products.Wood will be wet and dry shrinkage when exposed to air for a long time, and uneven wet expansion and dry shrinkage of wood will often cause wood cracking and deformation, affect the use and cause waste. If wet wood or dry wood products (such as doors and windows, floors, furniture, etc.) are manufactured, it seems good when they are just finished, but after a period of time, with the drying of wood, there will be door frame skew, floor warping, tenon loosening or board surface cracking and other phenomena, causing great losses. If the production unit dries the wood to the required moisture content before use, it can ensure the structural stability of the wood products and make them beautiful and durable.
(2) Increase the strength of wood and wood parts. When the moisture content of wood is lower than the fiber and saturation point, the strength of wood will increase with the decrease of the moisture content of wood. After drying, the cutting conditions can be improved, and the strength of wood structural parts, bonding strength and surface decoration quality of wood products can be improved. The thermal conductivity and electrical conductivity of wood change with the change of moisture content. To improve the thermal insulation and insulation of wood, it is necessary to reduce the thermal conductivity and electrical conductivity by reducing moisture content.
(3) Preventing wood degradation and decay.If wet wood is stacked in open air for a long time, decay or insect pests will often occur if proper measures are not taken. When the moisture content of wood is lower than 20%, the damage of fungi and pests can be greatly reduced. Therefore, generally in the production unit, the wood is dried to about 8-15% moisture content. This not only guarantees the inherent properties and strength of wood, but also improves the corrosion resistance of wood.
(4) Reducing the weight of wood.The moisture content of newly cut wood is even more than its own weight. After short-term storage and natural drying, its moisture content is still very high. After wood drying, its weight can be reduced by about 30-50%, which is helpful to improve the carrying capacity of vehicles. In a word, after drying, the quality of wood products can be guaranteed, the performance of wood can be improved, and the service life can be prolonged, thus saving wood. Practice over the years has proved that wood drying is an indispensable process in production and has become a specialized subject in science.
