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When wood is drying, the drying defects that often occur in wood drying include: internal cracks, surface cracks, end cracks, bending, shrinkage, charring, severe surface discoloration, and uneven drying.

Whether the sawn timber accumulation is reasonable or not directly affects the dry quality of the wood, and its importance cannot be ignored because the sawn timber accumulation operation is simple and heavy. There are some requirements for stacking operations as follows:

Drying benchmarks for new tree species need to be established. Before establishing new drying benchmarks, it is necessary to understand the structure of wood and its physical and mechanical properties, especially the relationship between wood density and drying shrinkage coefficient, and use the drying benchmarks of tree species with similar properties as a reference. . Or saw small samples and dry them in a drying box to observe their drying conditions. You can also put all kinds of wood to be dried together for drying experiments to observe the drying conditions of various test materials, and then according to various The reaction of sawn timber to drying is carried out by tree species. The steps are as follows:

The use of "carbonized wood" is divided into two categories: indoor use and outdoor use. Indoor use is mainly used for: floors, wall panels, interior decoration, furniture, doors and windows, blinds, window sills, sauna room floors and wooden structures, etc. Especially in the new residential buildings in northern my country, there are more and more ground heating floors. Too many cannot use solid wood flooring because of the unfavorable dimensional stability, and only laminate flooring or multi-layer solid wood composite flooring can be used. In the environment of floor heating, the release of formaldehyde from the adhesive layer of reinforced and composite floors causes indoor air pollution, which is a very difficult problem. The carbonized wood has good size performance and no air pollution, so it can be used for floor heating.

The advantages of dehumidification and drying: 1Save energy;. 2, due to the low drying temperature, so the design of the drying room and the use of materials are not high requirements, as long as reasonable air tight, waterproof box insulation. Factories can simply design and build drying chambers themselves; 3. The peak energy required in the drying process is low; 4, the use of electric energy, little pollution to the surrounding environment.

A wood vacuum dryer is a device that removes moisture from the interior of a container by drawing air from the container to achieve a predetermined vacuum. When dry, the canister is under vacuum. The jacket is heated with hot water (or steam or thermal oil). As the tank rotates at a low speed, the material continuously moves up and down, entering a "diamond-shaped trajectory" inside and outside the tank, and absorbs and evaporates.

The basic principle and drying essence of dehumidification drying and conventional drying are the same. Both rely on the convection heat exchange between the hot air in the wood drying room and the wood to be dried, and the air heats the wood and absorbs the moisture evaporated from the wood. The main difference between the two is the method of dehumidifying the air.

Air drying of wood is commonly known as natural drying. Air drying of wood is to stack wood in an open courtyard or under a ventilated shed, and use the heat in the atmosphere to evaporate the moisture in the wood to dry it. Although the method of air drying wood may seem simple, the drying process involves many physical laws, such as combining atmospheric drying with other drying methods, is a way to save energy.

Internal wood cracking occurs inside the wood, cracking along the wood rays, such as honeycomb, also called honeycomb cracking. There are no cracks on the surface, only sawing can be found. But it is usually accompanied by uneven appearance or significant shrinkage, or charring, or lighter weight. This is characteristic of over-drying.

Surface cracks are longitudinal cracks that occur along the wood rays on the outer surface of sawn timber (usually the outer cut surface of a chord-cut board). It is caused by excessive surface tensile stress in the early stage of drying